Security Services Tasmania Pty Ltd - (Joined Party)

Workers rehabilitation and compensation - primary liability - Whether a disc prolapse is an injury in the primary sense or an injury which is a disease - Pathways to liability - Causation - Sufficiency of evidence to establish causal connection with employment

Workers Rehabilitation and Compensation Act 1988

TCN v Hays Specialist Recruitment (Australia) Pty Ltd [2024] TASCAT 150;

Bradshaw v Tasmania Networks Pty Ltd [2019] TASSC 41;

Vos Construction & Joinery Pty Ltd v Norton-Smith [2016] TASSC 38;

Zickar v MGH Plastic Industries Pty Ltd [1996] HCA 31; (1996) 187 CLR 310;

Attorney-General (Tas) v Smith, Mary Morrison [1994] TASSC 62;

Mary Morrison Smith v Attorney General of Tasmania [1994] TASSC 183;

Accident Compensation Commission v McIntosh [1991] VicRp 65; [1991] 2 VR 253;

Military Rehabilitation and Compensation Commission v May [2016] HCA 19;

Nazar v Hydro Electric Corporation [2022] TASFC 11;

Kooragang Cement Pty Ltd v Bates (1994) 35 NSWLR 452

The decision has been anonymised for the purpose of publication.

1. The worker contends that he suffered an injury to his low back while employed by Hays Specialist Recruitment (Australia) Pty Ltd (Hays), and while contracted by Hays to undertake work for Security Services Tasmania Pty Ltd (SST) pursuant to a labour hire agreement.
2. At the time of the injury the worker was 37 years old. He was employed by Hays on 3 February 2021. Pursuant to his employment with Hays he undertook work with SST commencing in March 2021. He claims to have suffered the work injury in mid-May 2021.
3. The worker made a claim for compensation under the Workers Rehabilitation and Compensation Act 1988 (the Act), which was disputed by Hays. Hays and the SST deny that the worker has suffered a compensable injury. While the existence of a work injury is a matter of dispute, for convenience I have referred to the alleged work injury in these reasons simply as the injury.
4. The worker has filed two referrals pursuant to the Act:

(a) a referral pursuant to s 42 seeking a determination that he is entitled to workers compensation in respect to the injury; and

(b) a referral pursuant to s 138AB seeking a determination that he has a whole person impairment of not less than 20%, as a threshold to enable him to pursue a common law claim for damages in respect to the injury.

1. The referrals were heard together.
2. SST was joined to the referrals by order of the Tribunal on the application of the worker: see TCN v Hays Specialist Recruitment (Australia) Pty Ltd [2024] TASCAT 150.

1. It was not contentious that the worker has experienced a significant, incapacitating low back condition, being an L1/S1 left foraminal disc bulge impinging the left S1 nerve root causing S1 radiculopathy. He underwent a left L5/S1 microdiscectomy on 22 June 2022, a revision microdiscectomy on 22 July 2022 and an anterior lumbar interbody spinal fusion on 20 September 2023. Despite those procedures he remains incapacitated for work.
2. The fact of the disc bulge and consequent incapacity was not in issue between the parties. However, causation of that condition was in issue. The worker contends that his injury has the relevant causal connection with his employment so as to entitle him to workers compensation. Hays and SST say that it does not.

1. The work with SST involved digging trenches, laying cables and filling in trenches around the perimeter of the Bryn Estyn Water Treatment Plant. Another worker would use an excavator to dig trenches which were approximately 700mm deep and 300mm wide. The worker would stand in the trench and spread sand to make an even base layer. Cabling in pipes would then be laid in the trench and another layer of sand laid on top of the pipes. A plastic layer would be laid on top of the sand. Blue metal gravel would then be used to fill the trench in layers, spread by the worker using a shovel and his feet. After each layer of gravel was spread out the worker would compact it using a hand operated vibratory rammer known as a wacker packer. The wacker packer used by the worker is a construction tool with a motor at the top and a shaft under the motor, at the bottom of which is a vibrating metal plate that would compact the gravel. The worker estimated the weight of the wacker packer he used at near 100kg. It required two people to lift it into and out of the trench. The gravel layers would be repeated until the trench was full and then a larger wacker packer would be used on the final layer.
2. The worker and his colleagues would complete approximately 50m of trench and cabling per day.
3. The worker's statement of evidence described the circumstances of his injury as follows:

I have been shown the records of the Healthology Medical Centre. I was shown that there is an entry on the 19th of May 2021 that shows I reported back pain to Dr Harney. I believe that I had attended on that day because one of my children needed to see a doctor. As I was already going, I think I made an appointment to get a repeat script for my antidepressant...

I believe I went to work as normal on Thursday and Friday that week.

I do not think I was in serious pain on the 19th of May 2021.

I had noticed a bit of pain in the back of my leg that week, I believe, and I remember during my work day I told one of my colleagues - Cameron I think - "I feel like I've been bitten in the arse cheek". I did not think I had actually been bitten, it was a just an expression because the pain had been sharp and came on suddenly. I told him this after I was out of the trench and we were walking to the lunchroom.

At the time I felt the pain, I was in the trench scraping sand with a shovel. I felt a sharp pain in my left buttock.

This was before I went to the GP on the 19th. I don't know how long before exactly.

I recall a specific incident when I had a specific pain in my left buttock, but I didn't have any back pain at that point. I recall the back pain came on gradually at first, but became very bad by the Friday the 21st of May 2021.

At first I thought the problem was with my hamstring.

I know I was working for some days after this incident. I think I mentioned it to Sam or Greg. I thought it was a muscle strain. I really thought it was going to go away on its own.

The symptoms got worse and worse very quickly. From that weekend (the 22nd and 23rd of May) onwards the pain increased. On the weekend I could barely walk, I was lying in bed and pretty much crying in pain from my leg and buttock.

I had no or very little back pain at first and that is why I thought it was my hamstring.

I went to the doctor who gave me a medical certificate and organised some scans. I was in a lot of pain by this point.

1. The worker's description of the circumstances of the injury in his evidence in chief was consistent with his statement.
2. The worker produced a timesheet stating that he had worked Monday 17, Tuesday 18, Thursday 20 and Friday 21 May 2021. He worked full days on each of those days.
3. The worker expanded on his account in response to a proposition put to him by SST's counsel that he could not remember what he was doing when the pain first occurred:

MR WILKINS: I want to suggest, this is a short way of dealing with it, I am going to suggest to you to start off with that you can't remember what you were doing when the pain happened for the first time.....I remember, yep, I do. > > ... > > ....I want to suggest that you told both Dr Bonkowski and Dr Khurana that you were walking through the trench....Yep... > > When you felt pain in your left buttock like a pinch or bee sting....Working through the trench yeah. > > Well, sorry, that's not what you say. You say you were walking. Walking and working are different, aren't they?....Yeah well... > > Were you just walking......No. Well, working in the trench. > > Why did you tell them you were walking if you were actually doing something?.....Because that's what you're doing, walking up and down the trench all day. You know, obviously with a shovel in your hand too. And you, it's not like I am just walking up and down the trench just for something to do. > > I am not suggesting that you were, but you need to get from one point to another.......Yeah, yeah. > > You could have walked along the trench, couldn't you?......Yeah, obviously. But. Yeah. If you... > > Well, you told Dr Whitby that you were pulling dirt back into the trench for the next bucket sweep.....Yeah, I could have been like in the trench. > > Could have been that?....Pulling just like in the trench. You have to pull the dirt off the side back into the hole so the tractor does not pick it up as well. > > Ok. So can you remember exactly what you were doing? Were you smoothing out the sand with the shovel? Were you pulling it back into the trench?.....I think I was.... > > Were you simply walking.....Think I was just dragging some stuff along the pipes. I just remember laying the next load of sand on top of the pipes. > > Using the shovel......See cos' when you put the first load down... > > I am trying to understand because I cannot visualise it.......when you put the first load down as well, then you put the pipes. So you are kind of standing on two pipes as well. Round pipes like this. So you're near rolling your ankles standing on the pipes while you've got to cover them as well. > > Is that what happened at this time?......Well I mean that's what I was doing. I was up to the stage covering the pipes and I was on pipes and yeah. > > So you were walking along the pipe but you weren't using a spade at that time?......Yeah I had the spade and scraping. I was doing me job. > > But as I understand the system of work, after the pipe goes in, there is another layer of sand or gravel that goes on top of it.......yeah. > > So why are you scraping rather than waiting for the next layer to go on?.....Well there could have been a pile ready on half of the pipes, so you got to drag them over and start covering them.... > > Okay, and so this....If you understand. > > And so that's about hip height.....Sorry? > > So you are working at about hip height with the shovel.....Hip height? Yeah well yeah. Well you are down in the hole really. > > You are not bending forward though.......A little bit, yeah. > > Okay, I am trying to visualise it. It's actually the position you say you were in when you felt this bee sting......yeah. > > Do you remember?......Yeah, well, all I remember is I was on the pipes dragging sand. And all I say is I was in the trench. > > Okay, so you were not walking as you describe to Dr Bonkowski or to Dr Khurana. You might have been pulling dirt back in.......Yeah > > Okay.....I say walking cos' you are walking down the trench, up and down constantly, you know. > > Can I, you weren't, let's just get some things straight. You weren't using the wacker packer?......No, not when I felt the bite. > > You were not using the rammer?......No. > > You weren't digging?......No, I was scraping at the time. > > Thank you, and what, what, what are we talking about in terms of the amount that you are scraping? Just a shovel full or half a shovel full?.....I guess sometimes there is, like a mound, you know, in the hole > > But you're not pushing it all at once.....Oh well, you gotta dig into it and drag so much. If you understand. Or sometimes cos' see if it is.... > > Is this from your memory or is this is the type of.....This is what you got to do. > > But is this what you were doing....Yeah. Oh, at the time? > > Yeah.....Yeah, well pretty much there was a mound there. I was dragging it back onto the pipes. > > Okay, but you can't remember how much was there?......No, you know, I guess because normally as well, once when they put the second load you start covering the pipes load by load by load, if you understand and you spread that. > > Okay.....Well, was only pretty much had the load so it was just about to start another run, if you understand. > > So I am just trying to understand each other. You say that you were using a shovel to bring some dirt in that was on the side of the trench into the trench. And this was about 10 days before you went to the doctor. You felt a sting.....Mm. > > Is that your memory?......Well, so this is, people word stuff different as well. And like my memory is I was working in the trench, got bitten on the arse cheek. I did not exactly remember the date, the time. I know it was before lunch because I remember walking over to the lunchroom and telling Cameron after it happened.

4. On Wednesday 19 May 2021 the worker saw Dr Harney, who is a general practitioner (GP). He then saw another GP, Dr Shaunagh Jones, on the following Monday 24 May. Earlier that morning he emailed Hays in the following terms:

Hi Orla just letting you know that I won't be able to make work today and most likely tomorrow, as I have pulled my hamstring in my leg and haven't been able to walk all weekend. I have let Greg know and I am trying to get into a doctor today.

5. On 26 May 2021 the worker had a CT scan of his low back, which showed the disc prolapse. It also showed mild degenerative changes and mild disc bulges at L3/4 and L4/5. He saw Dr Jones on 28 May 2021 and she told him the of the results of the CT, prescribed pain killers and referred him for physiotherapy.
6. In examination in chief the worker said that when Dr Jones reported the results of the CT scan to him she told him that he had three crushed discs, at L3, L4 and L5. In cross examination by SST's counsel the worker acknowledged the seriousness of that advice:

MR WILKINS: If I can also, you said very early on in your evidence when you were being cross-examined by Mr. Jackson that Dr. Jones had told you, I think on the 28th of May, after the CT scan came back, that you had three crushed discs in your back?....Yes. Something along the lines. Yeah.

Yeah, you would have been pretty concerned about that?.....Well obviously, yeah.

I mean, that's, that's very, very bad news, isn't it?.....Yeah, well...

Yeah, and did Dr. Jones tell you that that was a serious matter?....Yep.

You were casual, so you weren't getting paid?.....No.

And as Mr. Jackson said, it took you three months to make a claim....Yes.

I don't need an explanation. I just want to make sure that I have got that right....

1. On 1 June the worker emailed Hays in the following terms:

I wanted to confirm with you that I should be putting in an incident form in [sic] for my back. > > I cannot remember a specific event that an injury occurred unfortunately but I remember the aches and pains post working and thought at first it was just a pulled muscle so took time off work and attempted pain relief and symptom management for muscle concerns. > > Looking at the work that I was doing it definitely would have been the cause of the pain - If I was not working I would not have had this injury - therefore the physical repetitiveness of the work that I was doing for the period of the last few months would have been the 1 issue that has now caused this injury. > > I am certain that I should complete an incident form regarding this and just wanted to conform [sic] this with you and ask how I go about this.

2. On 3 June 2021 the worker was sent an incident report form. He completed the form on 15 July 2021 and emailed it to Hays the following day. In the form the worker gives the date of the incident as 21 May 2021 and then describes the incident:

Between May 18th - 21st of May 2021 working at Tas Water I injured my back. I was completing tasks designated to my job - which included working in trenches, laying pipes, refilling trenches with sand and gravel along with other hands on jobs. By Friday the 21st of May I knew I was injured - I felt stiff/sore with aches and pains and remember feeling like I had pulled my hamstring (I had increased pain in the back of my leg) and by late afternoon and over the weekend I was unable to walk properly due to the injury and required to take the following 2 days off work. I contacted Orla Fleming (my Hays consultant) and told her of the injury and that I was heading to the Dr's for further advice. I was then reviewed at the Dr's - who sent me off for further investigations - I also gained a medical certificate to cover until the 28/5/21. The Dr sent me for a CT scan - completed on the 26th of May 2021 - results show damage to my lower spine and nerves causing my L5 disk compressed on my S1 nerves - plus 2 other bulging disks.

3. In response to an email from Hays the worker provided a further short statement dated 2 August 2021, in which he said:

As per your email you wanted some further information pertaining to the original incident report I submitted on the 16th of July 2021. > > I am unable to remember the exact time of the incident. I recall complaining of feeling though [sic] I pulled a muscle in my leg and thought at the time that was the extent of my injury. I reported the pain to my colleagues at the time on Tuesday 18 May 2021. > > I was working at TasWater Bryn Estyn Water Treatment Plant at Glenora Road, Plenty. > > Over 3 days it became worse and by Friday I could not work/walk properly (please see original incident report for further details and [indecipherable]). > > I was completing hard labour - repetitive work in trenches, working on uneven surfaces, laying pipes, refilling trenches with sand and gravel. > > I worked as a labourer since 9/3/21 - up until my injury was sustained and I was unable to physically work again. > > I have been to numerous Dr's appointments - physio appointments and further F/up appointments. Please get in contact with me for further information.

4. On 25 August 2021 the worker completed and gave Hays a workers compensation claim form, together with an initial workers compensation medical certificate dated 23 August 2021.
5. The worker explained that he delayed making a workers compensation claim because he hoped to get better and return to work, and because he had previously had a difficult workers compensation claim that had resulted in him losing a job that he enjoyed.
6. In the claim form the worker described the circumstances of the injury as:

I was completing tasks designated to my job including working in trenches, laying pipes, refilling trenches with sand and gravel and as per medical certificate I felt stiff and sore - feeling like I had pulled my hamstring - (increased pain in the back of my leg) - inability to walk properly.

7. The worker left the part in the form for the date and time that the injury occurred blank but provided 10 May 2021 as the date that the injury was first noticed. Time sheets produced by the worker showed that he did not work on Monday 10 May 2021, but did work the following four days that week. The worker explained that by the time that he made the claim he did not really remember when he had injured himself, so he put 10 May 2021, after a discussion with his GP, as the earliest date that he might have suffered the injury.

1. The worker did not call either of the colleagues that he says he spoke to of the onset of pain at work. He called his partner, who is a clinical nurse consultant at a major public hospital. Her evidence was that she and the worker separated in 2023 but were together for 15 years prior to that, which would put the commencement of their relationship at about 2008.
2. In respect to the injury her evidence was:

I do not have a clear recollection of what he told me happened when he hurt himself, or exactly when that was. Looking back, I think it was in May 2021 because that is when he went to the doctor and I remember that. I remember I believed that Scott had hurt himself at work but I can't recall him telling me anything specific about how it happened. I knew he was doing hard physical work which he had enjoyed and told me about. I recall he came home one day and said he was a bit stiff and sore, in the leg initially. He said there was cramping. I can't remember any significant issues prior to that.

I recall that it was around the time of our daughter [redacted] birthday that Scott complained of back and leg pain to me. He was unable to help set up the birthday party we had organised due to the pain. The party was on 22 May 2021.

1. She recalled the worker attending a physiotherapist on several occasions for muscle spasms in his back and his use of a TENS machine, around 20 years ago. In cross-examination she said that she was not aware of the worker having any earlier issues with low back pain. She did not refer to the worker's prior history of back pain, as detailed below, but the most significant history, other than GP attendances in August and November 2020, would have occurred before she and the worker commenced their relationship. Given the period of their relationship, the physiotherapy and TENS machine use referred to by her must have occurred at least several years after the GP records ceased to note complaints of low back pain in 2005.

1. The worker's general practice medical progress notes were tendered. They are, as is usual for medical progress notes prepared by busy practitioners, written in an abridged form and use common abbreviations. Unless otherwise stated I will refer to the contents of the notes with the abbreviations expanded or as a summary of the meaning of the abridged notes.
2. The initial consultation for the injury was on Wednesday 19 May 2021 with Dr Harney. She recorded that the worker presented with left lower back pain down to his left knee for the past two weeks. She noted a history of low back pain, that the worker reported no trauma and that he worked as a labourer, digging. On examination she observed that he had a tender left lower back, good power and a negative straight leg raising test. Her impression was musculo-skeletal pain. She recommended conservative treatment and that the worker return if he was not improving in a few weeks. She did not give the worker a medical certificate, explaining in a letter to the worker's solicitors dated 16 May 2025 that she did not consider him unable to work at that time.
3. On Monday 24 May 2021 the worker saw Dr Jones in respect to two matters, one of which was low back pain. Dr Jones recorded that the worker presented with low back pain, with pain from his left buttock to the back of his left knee, which had been worse over the last two weeks. She noted some 'dythesia' from the left buttock to left knee, which I take as likely meaning dysesthesia. On examination she noted that his range of motion was limited as the worker was avoidant and experienced pain. She observed a reduced flexion and a straight leg raising test on the left of 30° compared to 90° on the right. She recorded her impression as sciatica and noted "past chronic pain complicated workers comp". She prescribed analgesic medication and referred the worker for a CT scan.
4. The worker's next consultation was with Dr Jones on 28 May 2021. She recorded that the CT scan showed a disc prolapse at L5/S1 with left S1 nerve root irritation. She adjusted the worker's medication and referred him for physiotherapy. The referral letter from Dr Jones to the physiotherapist dated 28 May 2021 states that the worker "presented with non-work related back pain radiating down L leg".
5. The next recorded visit was with another general practitioner, Dr Shaun Thayer, on 16 June 2021. Dr Thayer's notes describe new low back pain with left leg radicular pain for weeks.
6. The worker returned to see Dr Thayer on 8 July 2021. Dr Thayer recorded low back pain with left radicular pain worsening at times. He noted that the pain had been present for about two months and was debilitating. On examination Dr Thayer detected no abnormality in respect to power and reflexes associated with the left S1 nerve. He referred the worker to the Royal Hobart Hospital neurosurgery clinic.
7. At the next consultation on 14 July 2021, Dr Thayer again noted a two-month history of low back pain with debilitating left leg radicular pain and no weakness or reflex abnormality of the left S1 nerve root distribution.
8. The worker saw Dr Thayer again on 12 August 2021. Dr Thayer noted that the worker's pain was largely unchanged, that he was on a neurosurgical waiting list and that he was to trial a nerve root injection.
9. The worker next saw Dr Thayer on 23 August 2021. His circumstances were unchanged. Dr Thayer recorded that the worker "wants to try for workers compensation with injury". He noted "injury likely ~ 10/05/2021", and "working in trenches at the time with digging and lifting". Dr Thayer provided the worker with the initial workers compensation medical certificate.
10. In the certificate Dr Thayer noted the worker's presenting symptoms as "lower back pain with severe radiating pain down left leg. Difficulty mobilising". He provided a diagnosis of left central disc protrusion at L5/S1 with left S1 nerve root impingement. In respect to stated cause Dr Thayer wrote "an incident which occurred on 10/05/2021". He wrote that the worker had stated that the injury had occurred as "onset of pain after working in trenches with digging and lifting".
11. The medical records include a letter by Dr Thayer dated 22 November 2021 with no addressee, apparently written in response to a report obtained by Hays' insurer from by Dr Ashish Jonathan. In his letter, Dr Thayer stated that there was no evidence of the worker experiencing a pre-existing S1 nerve root compression by history, examination or imaging, and in conclusion said:

Sure [the worker] doesn't have a specific date and injury time and mechanism, but he does report worsening over a period of days with now classical radiculopathy symptoms and a scan that is in concordance.

1. In a report to Hays' insurer dated 9 September 2021 Dr Thayer wrote:

Going from the notes as I was not the initial doctor, Mr Menzies reported worsening lower back pain on a history of lower back pain, no particular traumatic event but worsening with work as a labourer with a lot of digging. Eventually this pain became severe.

1. The worker saw a number of health practitioners for medico-legal reviews. Each recorded a history given by the worker.
2. The first in time was a review for Hays by Dr Jonathan, a neurosurgeon, on 29 September 2021. In his report dated 11 November 2021 Dr Jonathan described the mechanism of injury as follows:

[The worker] could not provide an exact date of the work incident, he said it occurred in early May 2021. [The worker] could not specify an injury incident, nor could he describe a mechanism of injury. > > [The worker] said he experienced pain in his back in the tailbone region and in the left hamstring while working in the trenches.

3. The worker arranged an assessment by Dr Janusz Bonkowski, a neurosurgeon, on 16 March 2022. In a report dated 29 March 2022 Dr Bonkowski described the circumstances of the injury in the following terms:

On or about 20 May 2021, whilst walking through a 300-millimetre-wide trench, he felt a grabbing sensation in his left buttock which he described as "like a little pinch". He thought it was probably a muscle pain because he felt it also going down into the hamstrings.

4. In a subsequent report dated 11 August 2022 Dr Bonkowski said the worker "had an initial "twinge" one day while shovelling". In cross -examination he said that that history was not obtained from the worker but from a report given to him, which he did not identify.
5. The worker arranged an assessment by Dr Farhan Shahzad, an occupational physician, on 26 May 2022. In his report of 30 May 2022 Dr Shahzad described the circumstances of the injury as:

He was putting up fences and digging 750-millimetre-deep trenches with a shovel. Once the pipes containing the electric cabling had been laid, the trenches were required to be filled with sand and gravel and packed with a Wacker Packer. The bobcat would bring the sand and gravel shovelled it into the trenches. There were a lot of large rocks and dirt which required to be shovelled out of the trenches whilst they were being excavated. [The worker] had been in [sic] the Wacker Packer for 5 minutes when he felt a sudden pain in the left buttocks and lower back. He was unable to walk due to extreme pain.

6. The worker arranged a review by a consultant psychiatrist, Dr Rajiv Siotia, on 11 May 2023. In his report of 1 June 2023 Dr Siotia set out an extensive history taken from the worker which included the following:

[The worker] was injured in a workplace incident on 20 May 2021. He was digging trenches with a shovel to lay electrical cable when "I felt like something suddenly bit me in the ass cheeks when I was in the trench". "I thought it was a hamstring and I pulled a muscle", he said.

7. The worker was assessed by Dr Louise Whitby, a certified professional ergonomist, on 11 July 2023. The purpose of the assessment was to provide him with an opinion on the ergonomics and work health and safety standards in the worker's work place. Dr Whitby undertook a detailed assessment of the work undertaken by the worker prior to his injury. In a report dated 11 September 2023 she described the circumstances of the injury as follows:

On or about 20 May 2021, it was a routine day. The team were constructing a trench for a perimeter fence. > > Just prior to lunch, [the worker] experienced what he described as a 'twinge' in his left buttock. The work he was doing at the time was following the excavator, pulling dirt back into the trench for the next bucket sweep.

8. SST arranged for the worker to be reviewed by Dr Gautam Khurana, a neurosurgeon, on 2 October 2024. In his report of 7 November 2024 Dr Khurana set out a description of the work that the worker was doing and then, in respect to the onset of symptoms and sequence of events, he said:

[The worker] said there was no particular injury incident or accident and no fall. He could not specify the exact date of any injury either. He said his symptoms occurred "around May" in 2021. He was working for TasWater and he was doing trench work. He was walking in the trench and he felt pain in the left buttock.

1. The worker had a history of low back problems prior to the injury. His evidence concerning this was:

I first saw a doctor about back pain in 2004. I had some back pain that I had been having on and off for a couple of years and he arranged some scans and some physiotherapy for me.

The physiotherapist diagnosed some issues with my back and leg muscles which we worked on and I had no further symptoms after that which I associated with that same issue.

I remember doing a few scans. I have been shown some reports from 2004.... I recall I went through a pain management program of some sort but don't really remember the details. I think I did physiotherapy at a clinic in Sandy Bay. My recollection is that they told me the problem was with my hamstrings and my back was ok.

I did some physiotherapy sessions, possible over a few weeks, but it could have been weekly for a few months or something like that. I think I had some exercises to do at home as well.

After that I recovered. I didn't have any ongoing treatment or persistent pain or restriction. It didn't stop me from working at all after the treatment.

1. The GP medical progress notes show that on 27 May 2004 he saw Dr Jones who recorded low back pain with full range of motion, normal straight leg raise and no neurological abnormality. He returned to see Dr Jones on 28 June 2004 complaining of ongoing severe back pain, again with full range of motion and no neurological abnormality. He asked for an x-ray. On 5 July 2004 Dr Jones noted a lumbo-sacral spine x-ray with no abnormality detected.
2. On 26 August 2004 the worker saw Dr David Ridgers who recorded "chronic low back pain no radiation two years possibly exacerbated twelve months ago green corp lifting rock".
3. On 31 August 2004 he saw Dr Tanya Schramm to discuss mechanical back pain. On a consultation on 1 September 2004 Dr Schramm noted that the worker had had many presentations with low back pain and had stated that he had had it for two years.
4. On 16 September 2004 he saw Dr Ridgers with persistent low back pain and spasm in his thoraco-lumbar region. Dr Ridgers recorded good range of motion with some pain on lateral flexion and no pain on rotation. He saw Dr Ridgers again on 4 October 2004, and was referred for a CT scan. He returned to Dr Ridgers on 31 October 2004, who noted that the CT scan was normal. The worker had a bone scan and saw Dr Ridgers on 28 October 2004 who recorded the results of the bone scan as no abnormality detected. In respect to the worker's lumbosacral spine the report of the bone scan included the following:

The bone scan does not demonstrate evidence of active skeletal pathology to explain the patient's current symptoms and particularly providing strong evidence against an active spondyloarthropathy. The very mild skeletal changes in the endplates of L5/S1 are of dubious clinical significance and may reflect mild endplate/disc pathology.

1. The worker subsequently saw Dr Ridgers for back pain on each of 30 November 2004, 7 February 2005, 9 May 2025 and 26 May 2005. Dr Ridgers referred the worker to a pain specialist at the pain clinic at the Royal Hobart Hospital. In the referral letter dated 2 November 2004 he stated that the worker "for several years has been persistently troubled by lumbar spine back pain with some minor posterior thigh radiation" and wrote "in spite of the normality of clinical examination and investigations [the worker] I think gives a fairly impressive history of significant low back pain".
2. The worker saw various GPs on quite a number of occasions in the years after May 2005 without any reference to back pain being recorded until 29 October 2015 when he saw Dr Jones, complaining of thoracic back pain following a lifting incident while working at a laundry, but made no complaint of lumbar back pain. It appears from the GP records that the worker made a workers compensation claim in respect to that injury, and received a clearance from Dr Jones on 11 December 2015.
3. The worker continued to see GPs from time to time after that, but did not make any further complaint of back pain until 6 August 2020. He made a workers compensation claim for a shoulder injury which Dr Jones recorded in a note on 24 March 2016 as having occurred on 20 March 2016. That injury required ongoing management over a period of around two years, during which none of the progress notes recorded low back pain.
4. On 6 August 2020 the worker saw Dr Jones for two matters, one of which was low back pain. Dr Jones recorded the history as "has been moving boat, lifting children, no specific event".
5. On 6 November 2020 the worker saw Dr Columbine Mullins for two matters, one of which was low back pain. Dr Mullins recorded the history as "lumbar back pain mainly on the left. Was moving a table this week and exacerbated pain". He noted flaring of pain, and pain radiating down both legs. He recorded muscle spam and undertook a physical examination with no abnormality detected.
6. The worker's next consultation for low back pain was the attendance on Dr Harney on 19 May 2021 in respect to the injury.
7. This history was not given in full to the medico-legal assessors, and in some cases is inconsistent with the history provided to the doctors. Dr Jonathan reported that the worker said that he had experienced low back pain and leg pain in 2004. Dr Bonkowski reported that the worker told him that he had some episodes of spasms in his back in 2004/2005 and had been pain-free as far as his back was concerned for 15 years. Dr Shahzad reported that the worker said that he suffered from back pain in 2004 and 2005. Neither Dr Siotia nor Dr Whitby made reference to any historic low back pain, but that probably reflects their focus on the worker's mental state and the ergonomics of the workplace respectively. Dr Khurana recorded being given a history of no spinal injuries or any major medical diagnoses.

1. Dr Jonathan, Dr Bonkowski, Dr Shahzad, and Dr Khurana gave evidence at the hearing. Reports of each were tendered, in which they each recorded and had regard to history provided by the worker, radiological investigations and a clinical examination.
2. Dr Jonathan considered that the worker did not suffer an injury, but rather a degenerative disease to which his employment did not contribute. In his report of 11 November 2021 he had particular regard to the absence of a precipitating event, concluding:

In my opinion, [the worker] has not suffered an injury, no injury date or time could be specified, no injury event was specified, and no injury mechanism was described.

[the worker]' condition is explained by the pre-existing degenerative disease of the lumbar spine causing an L5/S1 left paracentral disc protrusion which is causing compression of the traversing left S1 nerve root, resulting in a left S1 radiculopathy.

... ln my opinion, [the worker's] condition arises as a result of the degenerative disease of his lumbar spine. In my opinion, his employment with Hays Recruitment has not contributed to his. condition. I am of this opinion as [the worker] does not report a date of injury, injury incident or injury mechanism) He has pre-existing symptoms consistent with degenerative disease of the lumbar spine.

1. In a supplementary report dated 22 February 2023 Dr Jonathan stated that he had reviewed medical records which included radiological investigations and records of the microdiscectomy and revision microdiscectomy procedures. He said:

The operative findings and the pre-operative course indicate that the cause of [the worker] symptoms was the compression of the left S1 nerve in the narrowed left L5/S1 lateral recess.

This narrowing of the lateral recess was not caused by trauma. It was caused by the degenerative broad-based L5/S 1 disc bulge and the degenerative hypertrophy of the left L5/S1 facet joint. This confirms my previously expressed opinion that [the worker's] condition is caused by the degenerative disease of the lumbar spine and is unrelated to the alleged work injury.

I continue to maintain my opinions regarding causation and that [the worker] employment has not contributed to his need for surgery and treatment for his spinal condition.

1. In a supplementary report dated 28 February 2025 Dr Jonathan referred to Dr Harney's notes of the consultation on 19 May 2021, and said of them:

In my opinion this clearly indicates that in relation to the onset of back symptoms in May 2021 there was no injury at the workplace or elsewhere. This has been confirmed by 3 independent medical doctors.

Furthermore, the surgery consultation on 19 May 2021 clearly states that the straight leg test was negative and no neurological deficits. This clinical picture is inconsistent with an acute disc prolapse as postulated by Dr Bonkowski.

Experiencing symptoms caused by a pre-existing degenerative disease of the lumbar spine in the absence of a consistent injury event and mechanism of injury does not constitute a work injury. The symptoms [the worker] attributes to the "work injury' were symptoms that he had experienced in the past. The surgery consultation notes on 6 August 2020 indicate that [the worker] suffered back pain after moving a boat and lifting his children. On 6 November 2020 he experienced "lumbar back pain mainly on the left" which was exacerbated by moving a table and the pain was "radiating down both legs".

1. He did not consider that the worker had experienced an acute disc prolapse. He referred to the CT scan 26 May 2021 and said:

In my opinion there is L5/S1 disc degeneration characterised by loss of disc volume due to desiccation and bulging of the posterior disc annulus. There are no features to suggest that it is acute. There are multilevel degenerative changes affecting the intervertebral discs and facet joints. This is consistent with long standing degenerative disease of the lumbar spine and not an acute injury.

1. In a report dated 11 August 2022 Dr Bonkowski explained the process of a disc prolapse:

A disc prolapse occurs because the gelatinous central core of the disc (known as the nucleus pulposus) breaks through a rent or a defect in the binding and encircling tissue known as the annulus fibrosus; sometimes these fragments of disc material get stuck in amongst the annular filaments and it is then known as a contained disc prolapse. However, in other cases, the nuclear material ruptures through the annulus completely. It can then be constrained partially by a further membrane known as a posterior longitudinal ligament but, if it bursts through that, then it extrudes into the spinal canal where it lodges, often jammed against the nerve root and causing sciatica. This is known as a fully prolapsed or extruded disc.

1. Dr Bonkowski explained the significance of the pinch in his buttock as described by the worker, in the light of the CT scan:

It seemed self-evident to me that the initial pinching sensation was the fragment of disc material initially beginning to extrude itself from outside of the normal confines of the disc space. So it was the first harbinger of the disc prolapse.

1. In his report of 29 March 2022 Dr Bonkowski said that the left-sided L5/S1 disc protrusion shown on the CT scan of 26 May 2021 had the characteristic appearances of an acute disc prolapse. He summarised his opinion as:

[The worker] is a previously fit and healthy 39-year-old man who has developed an acute left-sided L5/S 1 disc protrusion with left S 1 sciatica. He has clinical evidence or motor and sensory under-functioning of the S1 nerve root distribution with sensory loss in the sole of the foot and weakness of plantar flexion of the left foot. Both the CT and the MR confirm a large focal protrusion.

The degree of degenerative change which would have pre-existed the prolapse is fairly minor and no more than I would consider normal for a man of his age who has done heavy physical work for most of his adult life. There is no doubt that there is an acute disc protrusion and I am of the opinion that the acute disc protrusion is as a result of his heavy physical work digging and filling in trenches whilst working on-site at TASWater. There is no history of any other non-work related events which could have precipitated the disc prolapse and it strains credulity to postulate such a large acute disc prolapse occurring either spontaneously or purely on the basis of fairly minor degenerative changes reported by the radiologist.

I am therefore of the opinion that the disc prolapse is directly related to his work.

1. Dr Bonkowski provided further explanation in the report dated 11 August 2022, saying:

Therefore, an acute disc prolapse has a density very close to the normal density of the cauda equina (the nerve containing sac which is largely water-like) on CT imaging; it can be so close at times that it can be difficult to distinguish and we are often reliant on loss of fat planes to see the disc. The disc material is also somewhat ill-defined or vague in its outline. That is exactly the appearance of the CT in [the worker's] case.

Once the disc has been present for some weeks to months, a gradual inflammatory and repair response results in the disc prolapse shrinking; it becomes more dense and becomes both smaller, develops a sharper outline, and a denser appearance. Eventually, it will even start calcifying. [the worker's] disc on CT was definitely not a chronic disc prolapse.

1. In oral evidence Dr Bonkowski said the following:

DEPUTY PRESIDENT: Dr. Bonkowski just hopefully a fairly simple question. There seems to be some disagreement between you and Dr. Jonathan as to whether, there are signs of acute disc prolapse or not. Can you just summarise for me very simply what, radiological signs indicate either acute disc prolapse or chronic disc prolapse and whether there are any other signs that differentiate between the two....Well, I think I summarised them in one of my supplementary reports. But essentially when a disc prolapses initially it is very hygroscopic. Hygroscopic means that it actually imbibes more water and so a disc prolapse once it's actually escaped from the disc space, it actually swells. It swells quite markedly, and as it swells and absorbs more water, its density on either CT or MR imaging becomes almost water like. Now the spinal canal is 90 per cent water or CSF, and so an acute disc prolapse looks very much quite similar to the CSF that it's jammed up against. And then what happens with time is that the disc prolapse then slowly shrinks up as the body mounts an inflammatory response. And as it shrinks up, it slowly becomes darker. And eventually once it becomes truly chronic, it often becomes calcified. So actually it has bits of calcium in it. It can almost ossify and all of this can be seen on a CT scan. Most of it can be seen on an MRI scan so that in fact there are differentiators between a chronic disc prolapse. I am talking about something that is 2 or 3 years old. I mean it depends on when, when does acute become chronic? I would have said that [the worker's] disc definitely looked in the acute category that if I had aged it, I would say at worst it would be months rather than years old. So when Dr. Jonathan, I mean when Dr. Jonathan disputed that there was an acute disc prolapse, I looked at the CT scan and I said, that's a bizarre opinion. I mean, it is uh, I was, I was I was quite amused by Dr. Jonathan's opinion. I still do not understand it. I have not had a coherent explanation from Dr. Jonathan why he disputes that it's an acute disc prolapse.

1. Dr Bonkowski said that his opinion could be verified by a radiologist's opinion, MRI or the surgeon's notes, but no specialist radiological opinion was provided, the material in evidence did not indicate an MRI in respect to the injury before 9 March 2022, and the surgeons' notes of the procedures were not in evidence, observing that the first surgery was in June 2022, both well after the period indicated by Dr Bonkowski for the gradual inflammatory and repair response. Dr Bonkowski's general comments on acute disc prolapse would put the prolapse within months of the CT scan, which was undertaken within a week after the worker's initial presentation at his GP, and his explanation of the significance of the pinching sensation as the harbinger of the disc prolapse would put the prolapse within the immediate period of the worker's work with SST prior to the CT scan.
2. Dr Bonkowski explained that a disc prolapse need not necessarily be a singular event:

It is a sequence of events consisting initially of a tear in the annulus followed by a herniation of disc material into the tear which can progress in a stepwise fashion to a full extrusion and the extrusion can then become increasingly symptomatic due to swelling by imbibing water and then an inflammatory response. Therefore, [the worker] had an initial "twinge" one day while shovelling, his sciatica started within a day or so, and over a period of days in a stepwise fashion he became increasingly bed bound with the large acute disc extrusion causing back pain and sciatica.

1. Dr Bonkowski described the primary cause of disc degeneration as genetic, but said that the degeneration would remain asymptomatic until something else happened, such as a disc prolapse.
2. Dr Thayer gave evidence. His medical career prior to entering general practice involved two and a half years as a radiology registrar at the Royal Hobart Hospital, and he was invited by counsel without objection to comment on the worker's radiology. He considered that the radiology prior to 2021 showed only mild degeneration. He was referred to an MRI of the worker's spine taken in 2015 in connection with the worker's thoracic back injury. He observed that it showed very mild lumbar disc narrowing. He said the following in cross-examination by SST's counsel in respect to differences between what was shown on the 2015 MRI scan and the 2021 CT scan:

MR WILKINS: But certainly by the time we get to these images, and I think you have agreed there is there's signs of degeneration....Yeah. Mild

Mild degeneration. And by the time we get to 2021, when the CT is taken at least in the levels above at three four and four five, there are bulges and there is there's degeneration, whether you call it mild or moderate or significant, I suppose there is going to be a matter of argument....Yeah, it might be.

And so something has I think you have just agreed with my learned friend that something has happened between 2015 on that high resolution MRI and the moderate resolution CT scan....Yeah, I would.

There is there is there is some, some process has gone on....Absolutely.

And I think you just said, we do not know whether that process is as a result of, a gradual degeneration process or a sudden degenerative process....Yeah, I would say, yes you don't in general. And I guess the only clue you get is the, the history and then you have to sort of go by that, but certainly when someone starts to report, I think I have gone over this, but report that sort of left leg going down to the ankle, then you start alarm bells ringing for an S1 nerve compression.

I think we can we can agree that, at some time in May there has been an event where, the disc has commenced to press on the nerve....Yeah, absolutely.

There is some at some point, some moment in time that's occurred....The history would be, would agree with that.

That because you do not get those full radicular symptoms down the left leg until there is that pressure....Absolutely.

And am I right in saying that the disc may be protruding but never get to that point?....Absolutely.

So it can be if we are looking on a continuum from 1 to 100, it might only ever get to 99 and it never presses on the disc....Yep, and you see that in spines, absolutely.

Yes. And so to take you but so in in these circumstances, can I suggest to you that we, we do not know in that moment before [the worker] symptoms came on where we were on that continuum?....No. 'Cos there's no objective findings, there is not even a subjective one, is there.

We simply do not know. Does the symptoms that are occurring in the, late in 2020 with the two incidents my learned friend took you to in August. Do they give us any indication that there might be some early signs that this is starting to become a bit of a problem?....No. There is there is at least ten things, probably more that can cause localised back pain. And so it could be a disc. It could be it could be ligament, it could be tenderness, it could be muscular. So it's hard to pinpoint that a disc is getting worse when people have when they present with worsening back pain like because there is a number of things that could.

And so when, when, and I think we've got some evidence of this from Dr Bonkowski who said that sometimes patients might just turn over in bed at night and have those symptoms....Well, well, that's a possibility because as we as we have already established that the disc can push and can get further and further and it might not touch a nerve yet. So you do not get those, those symptoms yet. That is a possibility.

It is that final moment that causes the symptoms....It can be. Yeah.

[The worker] reported to you that that final moment occurred whilst he was at work?....Yeah. Over a period of time, though, it seems as though in terms of looking at, there was a window of, of, of worsening and...

Over a short period of time....But yeah. Short in comparison. Yeah, yeah. If we are looking back at the 2004 incidents.

DEPUTY PRESIDENT: Just on that last point, Dr. Thayer in in your report or your proof of evidence at paragraph 12, you say [the worker] initially saw Dr. Jones a GP in our practice on 24th May 2021 reporting a two week history of worsening lower back pain. When you describe that history of worsening lower back pain, are you describing a history of worsening within that two week period or.... Yeah, I just went off her notes there. I had to go off her notes and yeah within a yeah that is what I deducted I guess. That it was a worsening lower back pain during that period,

In that two week period....Yeah, two week period, yeah.

1. Dr Shahzad addressed causation in his report of 30 May 2022:

In my opinion, [the worker's] complaints are caused by the abovementioned incident on 20 May 2021 whilst he was working with TASWater. His tole involved putting up fences and digging 750-millimetre deep trenches with a shovel. He was working on a Wacker Packer on a repetitive basis when he noticed the onset of left-sided lower back pain. This is causally connected and related due to the physical and manual handling nature of his role which requires him to be in a bent, forward posture and absorb significant vibrations. He has been heavily exposed to the use of a Wacker Packer whilst engaging in a physically demanding role.

1. In cross-examination by Hays' counsel Dr Shazad confirmed that the history described in his report, of the injury manifesting while the worker was operating the wacker packer, which was is contrary to the other evidence, was given to him by the worker. The following was put to Dr Shahzad by SST's counsel:

MR WILKINS: Thank you doctor. I am just going to repeat that question. If the history as to the onset of pain in May 2021 was wrong, would that necessarily make your opinion less valuable?....So if this happened, would that happen? Speculations. If the history provided to me was wrong or incorrect, would that change my opinion? It would change my opinion on causation, but not on the diagnosis.

1. Hays' counsel took Dr Shahzad to a reference in his report to the CT scan of 26 May 2021:

Now, at the top of page six, that recitation of that report continues and it speaks of facet joint degenerative changes at L3/4 and a generalised disc bulge, correct?....Yes.

At L4 five level. A generalised disc bulge and facet joint. Degenerative changes. You see that?....Yes. Yes.

And an L5/S1 a left central disc protrusion that causes compression of the traversing left S1 nerve root, etc.....Yes.

Now, forget about the L5/S1 level for a moment. Just concentrating on the degenerative changes and disc bulges referred to in respect of the L3 and L4 five level. Given, given that worker had told you that he suffered an injury on the 20th of May and this scan was done on the 26th of May six days later....Yes.

Those degenerative changes and those generalised disc bulges would not have occurred within that six days, would they?...Degenerative changes are generally are seen in long standing cases.

Long standing cases. Yes. Thank you. Did you look at the actual scans or did you just go on the report?....I went on the report.

Yes, thank you. At page six of your report under the heading Summary and Assessment you refer in the first line to an acute left sided L5/S1 disc protrusion. Why did you come to the opinion that that protrusion was an acute protrusion? As opposed to the long standing general disc bulges at L3/4 and L4/5?....So, so this is a gamut of observations with subjective and objective findings rather than just a sole reliance on imaging. When you are correlated history provided by the patient with the mechanism of injury with the onset of symptoms which were not pre-existing, which warranted him to have a scan and the scan to identify the source of the problem which did not exist before this injury. So that's how I come to the clinical judgement that it's an acute onset L5/S1 disc protrusion which corresponds to the physical findings. So the decision was made based on history, examination and observation of imaging findings rather than solely on what the scan shows.

1. Dr Khurana reviewed the history and the worker's radiology in his report of 7 November 2024 and noted that the worker has scoliosis and a congenitally narrow lumbar spinal canal with lumbar spondylosis which was present years prior to the injury. He expressed the opinion that there was, at some time around May 2021, an acute aggravation at left L5/S1, by way of a foraminal disc protrusion with left S1 root compression. In respect to the CT scan on 26 May 2021 he commented that it showed:

Multilevel lower lumbar spondylosis, spinal stenosis from probable congenitally narrow lumbar spinal canal, and what appears to be a relatively recent left-eccentric disc herniation/aggravation at L5/S1, beyond the pre-existing broad shallow disc-osteophyte.

1. Dr Khurana concluded that the worker's low back condition is a structural disease that had been present for many years and became symptomatic 20 years ago. He considered that it is constitutional and age-related, and was accelerated by chronic smoking, a congenitally narrow lumbar spinal canal and scoliosis. In the absence of a verifiable date or mechanism of injury he considered that the worker's short period of work with Hays out of a career of 20 years of manual work made no material contribution to his outcome. His report included the following assessment:

My diagnosis is symptomatic L5/S1 spondylosis. There is a substantial pre-existing structural and symptomatic history in relation to the lower lumbar spine. There has been longstanding low back pain and bilateral leg radicular symptoms, confirmed by Dr Thayer. I do not believe surgery at L4/5 has anything to do with the workplace, and I am not at all convinced that the L5/S1 ALIF was required as a result of the workplace injury, as opposed to predominantly pre-existing factors and some perineural granulation worthy of indirect foraminal decompression via the ALIF. There are intercurrent spinal structural developmental anomalies, including a narrow lumbar spinal canal and scoliosis. There is acceleration of spondylosis from the narrow canal, as well as the chronic smoking. There is now substantial functional overlay and catastrophising (all of this is well explained across a gamut of subspecialities, in the attached literature). In brief, I do not believe there was a lumbar spinal injury from Hays employment.

Aetiologically (see the attached articles for my general approach), I have considered Mr Menzies' age, his long-term smoking status (ongoing until at least 2022), the absence of a date and mechanism of injury (yet, known exacerbations/aggravations outside of the workplace as documented in what appears to be 2020, and also a history of life-long labouring work, in addition to relatively short duration of employment with Hays), the eventual progression of symptoms somewhere in May 2021 and the CT from May 2021 and its findings (see Imaging Analysis). I have also considered my observations and clinical examination (and interobserver variations), the documentary metadata (including evidence of out-of workplace spinal exacerbations and aggravations), the relevant literature (examples of which are attached), and my own professional training and experience. The key factors associated with the breakage in the chain of workplace causation in this matter are stated in the grey-highlighted text at the top of page 4 of my report.

From an apportionment perspective, I (like Dr Jonathan) am not convinced that there was a bona fide workplace injury here. I do appreciate/acknowledge that labouring activities were being undertaken with that employer, but they were also being undertaken lifelong for a period of up to a few decades before Hays, and that vastly outnumbers the trench digging and wacker packer activities in the mere two months of Hays employment preceding the workplace injury reporting. Again, all of this is also without specific mechanism/event or known date (as opposed to a range of dates), and so forth, and with a treating GP clearly and relatively contemporaneously documenting that no trauma was involved. This all needs to be considered in the context of the longstanding history and the imaging findings of chronicity and constitutional factors (see Imaging Analysis). I do not believe there is a material contribution from the Hays employment to the current diagnosis, that is, nothing beyond 10%. I believe there is an at least 90% contribution from a work-unrelated factors, that include: (i) the pre-injury longstanding symptomatic lumbar spondylosis with recurrent leg radiculopathy (substantially downplayed by Mr Menzies); (ii) the congenital spinal canal narrowing, scoliosis, and chronic smoking that accelerates the spondylosis present in this man (see attached articles); and (iii) probable further lower lumbar spinal aggravations (circumstances undisclosed by the assessee) leading to 2nd and 3rd surgeries being carried out. Those latent and probable aggravations were well after cessation of employment with Hays, and likely occurred during mid 2022 and in 2023.

1. Dr Khurana's opinion was informed by a number of learned journal articles, including articles authored or co-authored by him, supporting a contention that disc degeneration is primarily determined by genetic influences rather than aging, routine physical loading and mechanical insults and injuries. Dr Khurana considered that the worker had a degenerative process in his spine and that the precipitating event may be "very much a sort of a straw that breaks the camel's back".
2. Dr Khurana's evidence included the following:

DEPUTY PRESIDENT: Dr. Khurana, you said that [the worker] had chronic degenerative disease prior to May 2021, and then in May there was something which precipitated the focal left L5/S1 herniation. Would that the onset of that herniation be immediately apparent to the patient, and if so, would it appear immediately significant?....Am I addressing Deputy President?

You are. You cannot see me. I am off to the right.....Okay. Thank you. Sir, Deputy president, the extent of that disc herniation appeared rather large. The acute component, so I would have expected that had the, had it been suffered at a particular, doing a particular activity or whether it be anywhere that it would have been immediately apparent and it would have been immediately reported. It is large enough and compressive enough and acute appearing enough to have warranted that opinion.

1. He went on to say that he would not expect an amelioration of symptoms from a prolapse such as the worker's within a short period after the injury. That would be consistent with the worker suffering the injury in the week leading up to the weekend of 22 May 2021, but inconsistent with him not being immediately aware of a significant event.
2. The weight of the expert opinion is that the worker suffered the acute disc prolapse in May 2021 on a background of degeneration in his lumbar spine. In this respect I prefer the evidence of Dr Bonkowski and Dr Khurana, which is supported by Dr Shazad's opinion on diagnosis, to that of Dr Jonathan insofar as Dr Jonathan contends that there was no acute prolapse.

1. Under s 25(1) of the Act, an employer's liability to pay compensation arises from the suffering of an injury with a relevant causal connection to employment. Section 25(1) provides:

25. Liability of employers to compensate workers for injuries > > (1) If in any employment - > > (a) a worker suffers an injury, not being a disease, arising out of or in the course of his employment; or > > (b) a worker suffers an injury, which is a disease and to which his employment contributed to a substantial degree, within the meaning of section 3(2A) - > > his employer is, except as is otherwise provided by this Act, liable to pay compensation in accordance with this Act...

2. Section 3(2A), which is referred to in s 25(1)(b), provides:

(2A) For the purposes of this Act, employment contributed to a disease to a substantial degree only if it is the major or most significant factor.

1. 'Injury' has an inclusive definition in s 3:

(b) the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease where the employment was the major or most significant contributing factor to that recurrence, aggravation, acceleration, exacerbation or deterioration...

Paragraph (b) of the definition is commonly referred to as the extended definition of injury. Primary injury that is not an injury which is a disease or an injury within the extended definition is not defined.

1. In Bradshaw v Tasmania Networks Pty Ltd [2019] TASSC 41, a decision affirmed on appeal in Bradshaw v Tasmania Networks Pty Ltd [2020] TASFC 2, Brett J explained at [58] that the formulations 'the major or most significant factor' in s 3(2A) and 'the major or most significant contributing factor' in the definition establish "the necessity for employment to be the predominant contributing factor to the disease, or the aggravation or exacerbation of the disease, if the injury is to fall within s 25(1)".
2. In Vos Construction & Joinery Pty Ltd v Norton-Smith [2016] TASSC 38 Pearce J observed the following at [19]:

There are some observations which may immediately be made about these and associated provisions:

• there can be no liability unless a worker has suffered an injury;
• there are two categories of injury: an injury (not a disease) and an injury which is a disease;
• the statutory definition of injury is inclusive. It extends, but does not attribute a meaning to, the term injury when used in its primary sense;
• if an injury is not a disease, there is no liability unless the injury arises out of or in the course of the worker's employment. The words of connection to employment are disjunctive - it must have a causal or temporal connection with the worker's employment;
• if the injury is a disease, there is no liability unless the worker's employment contributed to it to a substantial degree. By s 3(2A), employment contributed to a disease to a substantial degree only if it is the major or most significant factor;
• a recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease is an injury, but only where the employment was the major or most significant contributing factor to that recurrence, aggravation, acceleration, exacerbation or deterioration.

1. In Bradshaw v Tasmania Networks Pty Ltd at [22]-[23] Brett J described three pathways to compensation arising from s 25(1):
   1. The effect of s 25(1) is that the employer's liability to pay compensation will arise where the worker has suffered an injury as defined, in the circumstances prescribed by that section. In respect of the two pathways to liability created by the section, Pearce J, in Vos Construction & Joinery Pty Ltd v Norton-Smith (above), said at [23]:

"[23] There is no dichotomy between an injury which is a disease and an injury which is not a disease. A worker is entitled to recover if he or she falls within either head of recovery_: Zickar v MGH Plastic Industries Pty Ltd_ (1996) 187 CLR 310 per Kirby J at 351, applied by McHugh, Gummow and Hayne JJ in Kennedy Cleaning v Petkoska at 310 [73]."

1. The authorities also establish that when regard is had to the extended definition of injury contained in subpar (b), there are in fact three available pathways to liability arising from s 25(1). These are:

(a) The worker suffers an injury in the primary sense, that is an injury which is not a disease, but is "something that can be described as a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state". See Military Rehabilitation and Compensation Commission v May [2016] HCA 19, 257 CLR 468, as discussed by Pearce J in Vos Construction v Norton-Smith. Such an injury will be compensable if it arises out of or in the course of the worker's employment.

(b) The worker suffers a disease to which his employment contributed to a substantial degree within the meaning of s 3(2A), that is, only if it is the major or most significant factor.

(c) By virtue of the extended definition of injury and its interaction with s 25(1)(b), an aggravation etc of a pre-existing injury or disease is an injury, but only where the employment was the major or most significant contributing factor to that aggravation. In the case of the aggravation of a pre-existing disease, it is the aggravation, not the underlying disease, which must be causally connected to the employment in the required sense: Long v Kmart Australia Ltd [2016] TASSC 6, 25 Tas R 237, per Porter J at [52].

1. In respect to an injury in the primary sense, Pearce J said in Vos Construction & Joinery Pty Ltd v Norton-Smith at [21]-[22]:
   1. If there is no injury (which is a disease), then consideration is to be given to whether there has been an injury in the primary sense. Although the Act does not define the meaning of the term "injury" in that sense, its meaning has recently been considered by the High Court in Military Rehabilitation and Compensation Commission v May [2016] HCA 19. At [52] the majority pointed out that whether there is such an injury will generally be determined by asking whether a worker has suffered something that can be described as a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state. The majority applied the reasoning of Gleeson CJ and Kirby J in Kennedy Cleaning Services Pty Ltd v Petkoska [2000] HCA 45, 200 CLR 286. Both cases considered legislation which is comparable, though not identical, to the Tasmanian legislation. In Kennedy Cleaning v Petkoska, at 300 [39], Gleeson CJ and Kirby J explained:

"[C]onsideration [must] be given to the precise evidence, on a fact by fact basis, concerning the nature and incidents of the physiological change accepted at trial. If this evidence amounts, relevantly, to something that can be described as a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state, it may qualify for characterisation as an 'injury' in the primary sense of that word."

1. See also the passages in their Honours' reasons in Kennedy Cleaning Services Pty Ltd at 298-299 [35] and 300-301 [40]. Their Honours earlier explained at 296 [28] that because of the disjunctive formulation in the phrase "out of or in the course of employment" many injuries "are compensable simply because they have occurred during the protected period of work hours, although they have no other connection with the worker's employment". They continued at 300 [39] by pointing out that if a physiological change in the sense described "happens within the protected period of employment, it is ordinarily compensable without proof of a specific causal connection with the workers' employment".
2. In respect to an injury within the extended definition Pearce J said at [24]:

24. In the event that the evidence does not establish an injury which is a disease or an injury in the primary sense, it may then be necessary to ask whether the case is one involving a recurrence, aggravation, acceleration, exacerbation or deterioration of a pre-existing injury or disease within the operation of par (b) of the s 3 definition. The concept of a par (b) injury was considered in detail by Porter J in Long v Kmart Australia Ltd [2016] TASSC 6. That case concerned a pre-existing disease, and not a pre-existing injury, but many of his Honour's observations, and the authorities he referred to, are applicable to both. In Tasmania, the terms "recurrence, aggravation, acceleration, exacerbation or deterioration of a pre-existing injury or disease" were introduced into par (b) of the definition of "injury" by amendment in 2001. The terms are commonly used in workers' compensation legislation in Australia. Judicial consideration of the terms is more commonly by reference to pre-existing disease rather than pre-existing injury. The terms recurrence, aggravation, acceleration, exacerbation and deterioration, when applied to a pre-existing injury, mean something which results in an increase or intensification of symptoms: Federal Broom Co Pty Limited v Semlitch [1964] HCA 34; 110 CLR 626 per Kitto J at 634 where his Honour considered what amounted to exacerbation of a disease. A recurrence, aggravation or exacerbation may arise as a result of external stimuli, or as a result of natural progression of the condition or symptoms: Cook v Midpart Pty Ltd [2008] NSWCA 151, 6 DDCR 316 at [41]- [49].

Injury in the primary sense or injury which is a disease?

1. In his statement of facts issues and contentions the worker contended that his injury is an L5/S1 disc prolapse caused by the aggravation, acceleration, exacerbation or deterioration of a pre-existing disease in relation to the disc. The worker did not contend that the underlying disease process was causally related to his employment with the Hays or work with SST.
2. However, in closing submissions the worker contended as his primary position that the prolapse was a primary injury that he had suffered in the course of his employment, and in the alternative that he had suffered an extended definition injury. The statement of facts issues and contentions is not a pleading and, subject to any issues of procedural fairness, does not restrict the case that the worker may advance.
3. It is undisputed that the worker has suffered a disc prolapse, and I have found that it was an acute prolapse. The evidence gives rise to the possibility that the worker may have suffered an injury in the primary sense or by an aggravation, acceleration, exacerbation or deterioration of a pre-existing underlying disease in the worker's low back. It was not contended that any such pre-existing underlying disease was caused by his work with SST or his employment with Hays.
4. The circumstance of a disc prolapse as an end-point rupture of a morbid condition is analogous to the rupture of a congenital cerebral aneurysm considered in Zickar v MGH Plastic Industries Pty Ltd [1996] HCA 31; (1996) 187 CLR 310. In that case the rupture had no discernible external cause, but it occurred while the worker was at work. Toohey, McHugh and Gummow JJ, who formed the majority with Kirby J, said jointly at 334-336:

The word "disease" has been considered by this Court in a number of decisions, including Favelle Mort Ltd v Murray [1976] HCA 13; (1976) 133 CLR 580 at 587 where Barwick CJ said:

"The word 'disease' is itself a word of some difficulty in this context, particularly in the expression 'contraction of a disease'. Properly used, disease denotes a morbid condition of the body. It may be initiated by some external cause or be idiopathic or autogenous."

But the word must be seen in the context in which it appears and be related to the circumstances of the case. To say that the aneurism was a disease does not answer the question whether the rupture itself can fairly be described as an injury.

Thus in Darling Island Stevedoring & Lighterage Co Ltd v Hankinson [1967] HCA 10; (1967) 117 CLR 19 a worker suffered pain and later paralysis caused by the collapse of one or two infected vertebral bodies. The consensus of medical opinion was that the infection, unless discovered and treated successfully, would in the ordinary course of events have progressed ultimately to produce a collapse of the vertebrae and incapacity. The Workers' Compensation Commission treated the matter as an aggravation, acceleration, exacerbation and deterioration of a pre-existing disease. However this Court held that the collapse of the vertebrae was an "injury" in the ordinary sense without resort to the extended definition in s 6(1)(b) of the Workers' Compensation Act 1926 (NSW). The decision is mentioned in Hockey v Yelland [1984] HCA 72; (1984) 157 CLR 124 at 137 per Gibbs CJ, 145 per Wilson J without any doubt being cast on its correctness.

In O'Neill v Lumbey (1987) 11 NSWLR 640 the respondent suffered a rupture of two aneurisms which occurred in his right cerebral artery, causing haemorrhaging into the intracranial space. The Court of Appeal (Priestley and Clarke JJA, Kirby P dissenting) held that the respondent had received an injury in accordance with the definition of injury in s 6(1) of the Workers' Compensation Act 1926 (NSW), that is, personal injury within the unextended meaning of that term. It is clear enough that Kirby P would have reached the same conclusion had he not felt constrained by authority, particularly Slazengers' Case.

In Accident Compensation Commission v McIntosh [1991] VicRp 65; [1991] 2 VR 253 the Appeal Division of the Supreme Court of Victoria held that it was open to the Accident Compensation Tribunal to find that the sudden rupture of blood vessels and consequent cerebral haemorrhage, arising from an arteriovenous malformation, was a "physical injury" under the relevant Victorian statute. Murphy J, with whom Crockett and Cummins JJ agreed, pointed out that there was general agreement that if some external agency precipitates a rupture, it is a physical injury. But, as his Honour observed:

"If the rupture is due to blood pressure, arteriosclerosis, arteriovenous malformation, or any other congenital or diagnostic aetiology, it is nonetheless a rupture - something quite distinct from the defect, disorder or morbid condition, which enables it to occur."

We respectfully agree with this observation and, in our view, nothing in Hockey v Yelland or in any other decision of this Court precludes its acceptance.

1. Both Hays and SST submitted that the prolapse was an injury which is a disease. Hays' contention was that some identifiable external trauma was required for the prolapse to be an injury. No authority was advanced for that requirement. In Attorney-General (Tas) v Smith, Mary Morrison [1994] TASSC 62 at [18] Zeeman J made the following obiter statement, which was endorsed by Underwood J on appeal in Mary Morrison Smith v Attorney General of Tasmania [1994] TASSC 183 at [17]- [18]:

Where an injury finds its origin in an external traumatic event causing immediate injury and is unrelated to any condition from which the worker is suffering, it is not an injury which is a disease because it cannot be said to have developed. That view is consistent with the approach taken by Crawford J in FAI General Insurance Company v Morrisson [1993] TASSC 115.

1. However, it does not follow from the fact that an external traumatic event causing immediate injury is not a disease that the absence of an external traumatic event means that the injury is a disease. Such a conclusion would be contrary to the approach taken in Zickar v MGH Plastic Industries Pty Ltd.
2. SST advanced submissions based on the approach in Mary Morrison Smith v Attorney General of Tasmania. In that case the Court determined that an idiopathic acute aneurismal subarachnoid haemorrhage, essentially the same type of injury that was considered in Zickar v MGH Plastic Industries Pty Ltd, was not an injury in the primary sense. The case was decided before Zickar v MGH Plastic Industries Pty Ltd. Counsel for SST pointed out that there was no relevant definition of disease in the Workers Compensation Act 1987 (NSW) which was considered in Zickar v MGH Plastic Industries Pty Ltd. I note, however, that the passage from the decision of Accident Compensation Commission v McIntosh [1991] VicRp 65; [1991] 2 VR 253 which was applied by their Honours in Zickar v MGH Plastic Industries Pty Ltd used the phrase "defect, disorder or morbid condition", which is materially similar to the definition of disease in the s 3 of the Act, which is "any ailment, disorder, defect, or morbid condition, whether of sudden or gradual development".
3. Counsel also submitted that a distinction arose from the inclusion of disease in the definition of injury in the NSW Act, while s 25(1) distinguishes between injury in a primary sense and disease. The definition of 'injury' in the Act as set out above is inclusive, and to my mind not materially different to that in s 4 of the NSW Act as considered in Zickar v MGH Plastic Industries Pty Ltd, which was:

(a) means personal injury arising out of or in the course of employment;

(i) a disease which is contracted by a worker in the course of employment and to which the employment was a contributing factor; and

(ii) the aggravation, acceleration, exacerbation or deterioration of any disease, where the employment was a contributing factor to the aggravation, acceleration, exacerbation or deterioration;...

1. As noted above, in Vos Construction & Joinery Pty Ltd v Norton-Smith Pearce J applied the observation of Kirby J in Zickar v MGH Plastic Industries Pty Ltd that there is no dichotomy between an injury which is a disease and an injury which is not a disease. Counsel for SST relied on the following passage from Pearce J at [20]-[21] to contend that the absence of an injury which is a disease is a condition precedent to finding that an injury is an injury which is not a disease:

20. In considering whether there is an injury which is a disease, the tribunal of fact is to consider whether the evidence establishes what may properly be described as an "ailment, disorder, defect, or morbid condition". If so, the tribunal of fact must then consider whether the worker's employment is the major or most significant factor contributing to the disease. If the evidence establishes both questions in the affirmative, then the condition is an injury.

21. If there is no injury (which is a disease), then consideration is to be given to whether there has been an injury in the primary sense....

1. If a worker establishes the existence of an injury which is a disease then there is no need to consider separately whether the injury is an injury which is not a disease but I do not take his Honour as stating that an injury which is a disease has primacy or must be excluded before consideration of the existence of an injury which is not a disease. His Honour's approach would remain as cogent if it were reversed in order. In Zickar v MGH Plastic Industries Pty Ltd at 351-352 Kirby J said:

A worker is entitled to succeed if he or she can bring a claim within either head of recovery. Logically, the first question to ask, including in cases which might otherwise be classified as manifestations of a "disease", is whether, notwithstanding that manifestation, the case falls within the primary definition of "injury" as a "personal injury arising out of or in the course of employment". In that context, the word "injury" should not be given a narrow meaning. It should have an ample application, in no way read down because Parliament, additionally, has provided a separate head of recovery for cases of work-related diseases.

1. More persuasively, SST contends that the facts establish that the condition was one that developed without any precipitating incident or any sudden and ascertainable physiological change, and that on that basis it should be considered an injury which is a disease. Dr Bonkowski's explanation of the process of a disc prolapse as a rupture of the annulus fibrosus and the posterior longitudinal ligament resulting in the nucleus pulposus of the disc extruding into the spinal canal; and the view by Dr Bonkowski and Dr Khurana that the size of the prolapse indicated a precipitating event; and Dr Khurana's opinion that the disc herniation would have had an immediate effect, together indicate a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state of the disc, using the well-known formulation referred to by Pearce J in Vos Construction & Joinery Pty Ltd v Norton-Smith, and consistent with the approach in Zickar v MGH Plastic Industries Pty Ltd. However, SST points to the progression from initial symptoms to incapacity over a number of days and the history of a two-week worsening given to Dr Jones. The definition of disease in s 3, being "any ailment, disorder, defect, or morbid condition, whether of sudden or gradual development", contemplates a condition which develops, whether suddenly or gradually. Dr Bonkowski's description of the worker having an initial twinge, then sciatica starting within a day or so, with increasing pain over a period of days in a stepwise fashion supports this contention.
2. In Military Rehabilitation and Compensation Commission v May [2016] HCA 19 the High Court considered the significance of 'sudden' in the phrase sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state. French CJ, Kiefel, Nettle and Gordon JJ said at [47] (emphasis in the original):

47. However, as the Full Court correctly held, "suddenness" is not necessary for there to be an "injury" in the primary sense. A physiological change might be "sudden and ascertainable". A physiological change might be "dramatic". The employee's condition might be a "disturbance of the normal physiological state". That an "injury" in the primary sense can arise, and can be described, in a variety of ways does not mean that "suddenness" is irrelevant. As the Full Court said, "suddenness" is often useful where there is a need to distinguish a physiological change from the natural progress of an underlying (and in one sense, closely related) disease (as occurred in Zickar v MGH Plastic Industries Pty Ltd and Kennedy Cleaning). But it is the physiological change - the nature and incidents of that change - that remains central. (Footnotes omitted).

52. ...The third question is - does the evidence demonstrate the existence of a physical or mental "injury" (in the primary sense of that word)? Generally, that will be determined by asking whether the employee has suffered something that can be described as a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state. However, that judicial language is not to be construed or applied as if it were the words of a statute defining a necessary condition for the existence of an "injury (other than a disease)". The language of judgments should not "be applied literally to facts without further consideration of what is conveyed by the reasoning" in the cases from which it is derived, or without regard to the text and scheme of the Act.

1. The physiological change, being the central issue identified in Military Rehabilitation and Compensation Commission v May, is in this case the rupture of the disc and the extrusion of the nucleus resulting in impingement of the S1 nerve root. Notwithstanding that that process might not have been sudden in the commonly accepted sense of that word, or that it can be seen to have developed, I am satisfied that the disc prolapse is, in this circumstance, a dramatic physiological change and an injury in the primary sense to be considered under s 25(1)(a).

1. The classification of the worker's injury will identify the relevant test of causation, but does not itself establish a causal connection with his employment.
2. Even allowing for the fact that the worker was not particularly eloquent and described his memory as 'crap', and that some of his engagement with reporting doctors occurred well after the occurrence of the injury so as to potentially blur recollection, the circumstance he advances are so vague and inconsistent with contemporaneous and other records as to timing, occurrence and mechanism of injury that for the reasons set out below I am unable to discern a sufficient case causally connecting the injury, however classified, to his employment.
3. Section 25(1)(a) uses the common formulation "out of or in the course of employment" as the test for a primary injury. 'Out of' requires a causal connection with employment, while 'in the course of' requires only a temporal connection: Vos Construction & Joinery Pty Ltd v Norton-Smith at [19], Nazar v Hydro Electric Corporation [2022] TASFC 11 [8], [14]. Thus, if the disc prolapse is a primary injury the worker will be entitled to compensation if the work undertaken in his employment caused the injury, applying a common sense evaluation of the causal chain as described by Kirby P in Kooragang Cement Pty Ltd v Bates (1994) 35 NSWLR 452 at 463-464, or if he was engaged in employment when the injury occurred.
4. The salient feature of this case is the vagueness and variability of the evidence as to the date, circumstances and mechanism of the injury, even on the worker's case.
5. The worker was uncertain as to precisely when the injury occurred. He experienced pain before he saw Dr Harney on 19 May 2021 but he did not know how long before. He said that the injury occurred when he was in a trench scraping or dragging sand with a shovel and manifested as a sharp pain in his left buttock. He had noticed a bit of pain in the back of his leg that week and recalls telling a colleague that "I feel like I have been bitten in the arse cheek". He did not have pain in his back at that time but rather pain in his left buttock. The worker continued to work. He initially thought that he was having a problem with his hamstring, and then a muscle strain. He had no or very little back pain at first and that is why he thought it was his hamstring. He was not in serious pain when he saw Dr Harney on Wednesday 19 May 2021. He said that the back pain came on gradually at first but that it was very bad by Friday 21 May. Despite that, he worked a full day on the Friday, and did not make any complaint to his colleagues, Hays or SST. He said that by the following weekend of 22 and 23 May he was in significant pain. He contended that on that weekend he could barely walk and was lying in bed with very significant pain in his leg and buttock and that from that weekend onward the pain increased.
6. The worker was generally vague in his recollection, and his oral evidence as to the circumstances of the injury lacked detail and had a sense of reconstruction rather than memory. There is no contemporaneous record of the circumstance described by the worker, either in his reports to his employer or his medical records. Indeed they tend to contradict the worker's evidence as to the particular circumstances of the injury.
7. The worker's description of the onset of his symptoms was inconsistent with Dr Khurana's opinion that the extent of the disc protrusion was such that it would have been immediately apparent and significant. The worker's evidence is more consistent with Dr Bonkowski's description of a progressive process, which further muddies identification of a precipitating event.
8. The worker's evidence was not corroborated by his partner in respect to some significant matters that she might have been expected to confirm. She made no reference to the worker describing a sudden sharp onset of pain in his buttock, or identifying any incident, just that he was a bit stiff and sore. She did not describe a progressive worsening of his condition over the period identified by the worker. The birthday party that she used to identify the onset of his complaints was on the Saturday of the weekend that the worker contended that he was bed-ridden and crying in pain. His partner made no reference to that. Given her profession as a nurse the lack of detail in her evidence in respect to an episode that, if the worker is accepted, was the beginning of a very significant episode in their joint life is somewhat surprising.
9. The worker said that he told to his co-workers of the instance of his buttock pain. They were not called by him. The worker's explanation for not calling his co-workers was that they were employed by Hays or SST, who could have called them. However, their significance was raised by the worker and his failure to call them gives rise to an inference that they would not have assisted his case.
10. The worker's contemporaneous reports to Hays differ to his evidence at the hearing. They do not identify a precipitating event, or expressly refer to the sharp sudden pain, or refer to the initial acute pain occurring in his buttock, or in the first instance identify any link with work. On Monday 24 May 2021 the worker emailed Hays to say that he had pulled a hamstring. He did not advise that he had done so at work. On Friday 28 May he was told by his GP that he had a disc prolapse, which he understood to be three crushed discs and to be a serious matter. On Tuesday 1 June 2021 he emailed Hays indicating for the first time that his problems were caused by work. He referred to his back, but did not refer to the disc injury. He did not refer to the sudden sharp onset of pain he described in his evidence. He described remembering "aches and pains post working". He could not identify a particular causal event and put his problems down to physical repetitive work over the previous few months. He did not identify an incident where he felt a sudden sharp pain or the onset of symptoms while scraping or dragging sand with a shovel or any other circumstance.
11. The worker was provided with an incident report form on 3 June 2021 but did not return it until 16 July 2021, almost six weeks later. In the incident report the worker identified the incident date as 21 May 2021, but stated that he was injured between 18 and 21 May 2021. Again, he did not identify a particular incident or refer to the sudden onset of pain, but rather to having increased pain in the back of his leg. On that occasion he did refer to the low back pathology identified by the CT scan. In a further statement to Hays on 2 August 2021 the worker said that he reported pain to his co-workers on 18 May 2021 and referred to completing hard labour without reference to a particular acute onset of pain or saying that it occurred when he was scraping or dragging sand with a shovel.
12. In the claim form the worker described his work broadly and did not refer to scraping or dragging sand as the precipitating event.
13. The worker was uncertain as to the date of injury, variously identifying it as 10 May, between 18-21 May and 21 May 2021.
14. In none of the reports did the worker describe his injury in the way he put it to the Tribunal in his evidence.
15. The history recorded in the GP medical records as being given by the worker also differs in significant respects to the worker's evidence. In considering this I have had regard to the abridged nature of notes in medical records and the likelihood that the doctors were interested in information relevant to diagnosis and treatment rather than legal causation.
16. On 19 May 2021 Dr Harney recorded that the worker had had low back pain for two weeks with no traumatic cause. This was the worker's first GP attendance, which on his evidence occurred within a day or two of the injury, with no recorded reference to the sudden onset of sharp pain or to the problem occurring while scraping or dragging sand. He saw Dr Jones on 24 May 2021, the Monday following the weekend, which on his evidence the worker had spent lying in bed crying in pain. Dr Jones' note does not reflect that history, and refers to low back pain being worse over the preceding two weeks, rather than a sudden sharp onset the week before. Dr Jones' referral for physiotherapy expressly referred to the worker presenting with non-work related back pain.
17. By Friday 28 May 2021, following his consultation with Dr Jones on that day, the worker was aware that the CT scan had shown a serious condition in his lumbar spine. By then he had had a week of serious incapacitating pain. He was a casual employee and was not paid while he was off work. He had previously made workers compensation claims in earlier employment for a thoracic back injury and a shoulder injury. Despite his understanding that he had a serious condition and his awareness of workers compensation he did not make a claim for some three months. Neither the worker nor his partner gave evidence of them discussing whether he should delay making a claim. There is no evidence that he discussed making a claim with his doctors before the appointment with Dr Thayer on 23 August 2021.
18. There was no reference in the medical progress notes to any connection with work until the appointment with Dr Thayer on 23 August 2021 when Dr Thayer noted that the worker "wanted to try for workers compensation", which even allowing for the nature of GP progress notes is somewhat equivocal. Dr Thayer did not record an incident of sudden onset of sharp pain, or the activity of scraping or dragging sand with a shovel, but he did record that the worker was working in trenches with digging and lifting. In his letter of 22 November 2021 Dr Thayer noted that there was no specific date, time or mechanism of injury. There is no explanation in Dr Thayer's notes for the express and implied absence of a causal link with work in the earlier notes by himself or the other GPs seen by the worker. In his report to Hays' insurer Dr Thayer described the worker as experiencing worsening lower back pain on a history of lower back pain that eventually became severe. Dr Thayer and the Worker worked out that Monday 10 May 2021 was the earliest date for the injury, but there is no explanation as to their reasoning for that date. The worker did not work on 10 May 2021. He worked the following Tuesday to Friday, and Monday, Tuesday, Thursday and Friday the following week before having time off. He used 10 May 2021 in his claim form notwithstanding the other dates he previously provided to Hays.
19. The health practitioners reviewing the worker for medico-legal purposes provided varying accounts of history given by him. They are largely consistent in respect to an initial sensation in the left buttock or hamstring, but vary as to the description of that sensation and the activity being undertaken at the time.
20. Dr Jonathan stated that the worker could not identify a date, incident or mechanism of injury. That history should be considered with care. In cross-examination Dr Jonathan explained that he had asked the worker how he was injured, and the worker had said working in the trenches. Dr Jonathan did not ask further questions to follow up that general response. The worker's counsel was critical of what he described as Dr Jonathan's reticence to make further inquiries of the worker, and referred to several previous cases involving Dr Jonathan in support of that criticism. Dr Jonathan said that he believed that he could only have probed that issue further by asking leading questions which he considered would put words in the worker's mouth. That is, with respect, a surprising and erroneous belief in an experienced medico-legal consultant. It is entirely appropriate for an examining doctor to follow up a general response with open ended questions to elicit further detail, or even leading questions where appropriate. However, Dr Jonathan was the first doctor to assess the worker for medico-legal purposes, within six months of the injury, and the history taken by him, of no incident or mechanism of injury is consistent with the worker's contemporaneous reports to Hays following the accident.
21. Dr Bonkowski describes being given a history of a grabbing sensation like a pinch while the worker was walking in a trench. That history indicates a temporal relationship with work, but not a mechanism of injury.
22. Dr Shahzad recorded a history in which the worker was injured while operating a wacker packer. No other evidence, including the worker's, supports the worker experiencing the initial pain when he was operating the wacker packer. No other evidence, including the worker's, referred to the worker experiencing extreme pain on the occurrence of the injury or being unable to walk due to the pain. Given Dr Shahzad's concession in cross-examination concerning history and causation his evidence is of little value in considering causation.
23. Dr Siota and Dr Whitby were not directly concerned with physical causation. They did not attend the hearing and were not cross-examined. Dr Siota recorded that the worker was digging when he felt a sensation like a bite in his left buttock. Dr Whitby's description that the worker felt a twinge in his left buttock while pulling dirt back into a trench is the account most consistent with the worker's evidence of scraping or dragging sand and the first, and only, record in the evidence of the version that the worker advanced in his evidence.
24. The last doctor to medico-legally review the worker was Dr Khurana. Dr Khurana recorded a history that was essentially the same as that recorded by Dr Bonkowski.
25. Setting aside the histories reported by Dr Siota and Dr Whitby, and the clearly erroneous history taken by Dr Shahzad, none of the doctors who assessed the worker recorded a history of a particular time or date of injury, a precipitating event or a mechanism of injury. None were given a history in the terms of the worker's evidence given at the hearing.
26. The reports of each of the experts were available to the worker in advance of the hearing. He did not give evidence as to what he told the various doctors or evidence to address or dispute the varying histories or inconsistencies with his account of the circumstances of the injury.
27. There is a great deal of confusion and no certainty as to the date on which the worker first experienced the claimed sudden onset of pain. The worker himself was uncertain. The initial GP records refer to a history of two weeks of pain, or worsening pain in contradiction to the worker's evidence.
28. There is also uncertainty in respect to the onset of symptoms. The sudden sharp pain, or pinch, or bite, he described as experiencing in his buttock was not recoded in his medical notes, or his reports to Hays. The first reference appears to be in the history recorded by Dr Bonkowski in March 2022. Dr Bonkowski's opinion as to the cause of the disc prolapse actually being the work undertaken by the worker relies on that history. The reports to Hays refer to pain in the back of his leg. The initial GP notes record low back pain for two weeks, and expressly note that there was no trauma. When Dr Jones referred the worker for physiotherapy she considered that the condition was not related to the worker's work despite being aware of the labouring nature of the work. I am not satisfied that the sudden onset of symptoms occurred in the circumstances as described by the worker. Even if it did occur, it was not associated with the immediately apparent serious consequences of a significant disc prolapse as described by Dr Khurana. It would be more consistent with being a harbinger of prolapse as described by Dr Bonkowski, which on that scenario logically must have subsequently progressed to a frank prolapse.
29. There is also uncertainty as to the mechanism of injury. The worker says that there is no evidence of any event outside work that could be said to have precipitated the disc prolapse. That is not to the point: an absence of evidence is not evidence of absence. The worker says that the initial injury occurred while he was pulling sand into a trench with a shovel. That history was not given to his doctors, his partner, Hays or the medico-legal doctors actually looking at causation. Dr Harney recorded no trauma and described a worsening of low back pain by reference to the worker's history of low back pain. Dr Jones apparently formed the view that the injury was not related to work. The first record of that circumstances advanced by the worker was the history recorded by Dr Whitby in July 2023, or, less specifically, by Dr Siota in May 2023.
30. Dr Khurana described the primary cause of disc degeneration and prolapse as genetic. Dr Jonathan agreed that it is no longer accepted that heavy manual work correlates with degeneration, but said that a manual worker would be more aware of problems than a sedentary worker. Dr Bonkowski described the primary cause of disc degeneration as genetic, but said that it would remain asymptomatic until something else happened, such as a disc prolapse. Dr Khurana considered that the worker had a degenerative process in his spine and that the precipitating event may be "very much a sort of a straw that breaks the camel's back". Dr Thayer described that final event as occurring over a period of time, which he described as a window of worsening that was short, but contextualised that shortness by comparison to the worker's previous experience of low back pain in 2004.
31. None of the medical opinion explained that the activity of scraping or dragging sand actually described by the worker precipitated the injury. Dr Bonkowski and Dr Khurana considered that an event would have precipitated the disc protrusion, but that event and the mechanism by which it precipitated the disc prolapse is not apparent from the history given to them by the worker or the accounts in the GP records by several different doctors. It is not surprising that no doctor causally linked scraping or dragging sand to the disc prolapse, as the worker did not provide that history.
32. In view of the contemporaneous accounts given by the worker to his doctors and Hays and his subsequent accounts to medico-legal assessors, and the absence of corroborating evidence from his co-workers and partner, I do not accept the worker's evidence as to the sudden sharp pain occurring at work as he described or that the injury occurred while he was scraping or dragging sand with a shovel. It is implausible that within a few days of this occurring he would tell Hays that work caused his injury but he could not recall a specific event and that he simply remembered aches and pains post working. There is no explanation for why he did not provide the description given in his evidence to his doctor, Hays or the medico-legal assessors. It was not given to Dr Thayer when the worker discussed with him making a claim. If the circumstances described by the worker occurred, given the serious incapacitating nature of the injury, the worker's explanation for delaying the making of a claim is implausible. I consider that his description is likely a product of him reconstructing a plausible circumstance in the context of the disputed claim, a description that developed over time and was informed by hindsight.
33. I am not satisfied that the disc prolapse occurred in the course of the worker's employment, and in particular the work he undertook with SST, or that that work caused the disc prolapse or substantially contributed to it.
34. In the event that I am wrong that the disc prolapse is an injury in the primary sense, I will also consider whether it satisfies the causation requirements for an injury which is an aggravation, acceleration, exacerbation or deterioration of the underlying disease process. For convenience I will refer to an aggravation, acceleration, exacerbation or deterioration collectively as an aggravation.
35. The evidence showed that the disc prolapse occurred in the context of a history of low back pain and degeneration as disclosed in the CT scan. Radiological investigations prior to 2021 disclosed some mild disease process in the worker's spine. The GP records disclose a history of significant low back pain for a period of about two years up until mid-2005, which was serious enough to result in a referral to a pain clinic, then a period of about 15 years without complaint. At some time during that period the worker received physiotherapy and used a TENS machine. The worker then twice had consultations for low back pain or an exacerbation of low back pain serious enough to warrant raising with his GP within roughly nine months before the injury. On 6 August 2020 Dr Jones recorded low back pain with no specific event and undertook an examination. Dr Mullins recorded left sided lumbar back pain on 6 November 2020, six months before the injury. He noted that the worker "was moving a table this week and exacerbated pain", which presupposes existing low back pain, and that the pain radiated down both legs. The worker saw another GP on 24 November 2025 with no reference to low back pain being recorded, and Dr Mullins did not include that condition in a Centrelink form identifying the main medical conditions affecting the worker's capacity to work. These facts suggest that the condition was not severe, but it was sufficient for Dr Mullins to undertake a full examination and to record having discussed "red flags" with the worker. The medical progress notes were available to the worker prior to the hearing, but his evidence in chief did not address this, and his evidence when cross-examined as to this attendance was vague. Despite the temporal proximity to the injury this history was not provided to the assessing doctors.
36. It was not contended by the worker or suggested in any other evidence that the underlying disease process or earlier complaints of pain were caused by the worker's employment with Hays. However, if I am wrong as to the injury being an injury in the primary sense, the worker's case raises the possibility of an aggravation of an existing condition as a result of an external stimulus. The injury represents a significant worsening of underlying problems. In particular, as explained by Dr Thayer, although there are some records of neurological symptoms and radiation of pain into the worker's legs prior to the injury, the radicular symptoms consistent with the S1 nerve root impingement apparently relate to the occurrence of the injury, as does the worker's incapacity. If the disc prolapse constituted an aggravation it will be compensable if the worker's employment was the major or most significant contributor to that aggravation.
37. SST submitted that in order for there to be an aggravation of a disease there needs to be existing symptoms that are increased or intensified, and that there can be no injury within the extended definition as the worker's evidence was, despite the medical records, that he did not have pre-existing symptoms. It would seem surprising that an aggravation of a previously incapacitating disease would be compensable but an aggravation of a clinically silent disease or non-incapacitating process would not. It may be that the operation of s 3(5) of the Act, which deems an injury which is a disease to occur when it results in partial or total incapacity, means that an aggravation of a clinically silent condition resulting in incapacity would be simply be considered under s 25(1)(b), which would also require meeting a test that employment was the most significant contributor to the incapacitating condition. I do not see a material difference between worsening of existing symptoms of a condition to cause incapacity and worsening the condition to cause symptoms causing incapacity. However, given my conclusions as to causation I do not need to determine the issue.
38. The factors contributing to the disc prolapse identified on the evidence were the worker's genetics, his chronic smoking, his congenitally narrow lumbar spinal canal and scoliosis, and the likelihood of some precipitating event, which might be a last straw event. The only relevant factor that might arise from the worker's employment is the precipitating event.
39. For the same reasons that I am not satisfied the injury arose out of the worker's employment, in the absence of evidence establishing a precipitating event I am not satisfied that his employment was the most significant contributor to any aggravation constituted by the disc prolapse.
40. The onus of proving an entitlement to workers compensation lies with the worker: s 49(2) of the Act. The case for a relevant causal link between the injury and the worker's employment is at best speculative, whether the test of causation is that applying to a primary injury or to an injury within the extended definition.

1. I am not satisfied that that the worker has met his onus of proving that it is more probable than not that the injury occurred out of or in the course of the worker's employment, or that the employment was the major or most significant contributing factor to the injury.
2. Issues were raised at the hearing as to the proper approach to an assessment of whole person impairment taking into account pre-existing impairment, and whether a jurisdiction arose in respect to payment of medical expenses before the expenses were claimed in accordance with the Act. Given that the worker has failed to establish primary liability it is not necessary to consider those matters.
3. Accordingly:
   1. The worker's referrals are dismissed.