1. On 8 September 2025 the appellant employer, Central Tablelands Water lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Robin Alexander Mitchell, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 11 August 2025.
2. The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act):
   • the assessment was made on the basis of incorrect criteria, and
   • the MAC contains a demonstrable error.
3. The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made.
4. Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules.
5. The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed

1 March 2021 (the Guides) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5). "WPI" is reference to whole person impairment. "Baseline WPI" is a reference to the total WPI assessed before deduction for the effect of pre-existing injury, condition or abnormality pursuant to s 323 of the 1998 Act.

1. On 2 July 2025 this matter was referred to the Medical Assessor for an assessment of the cervical spine, relating to two injuries. The first date of injury was 6 February 2018 and the second date of injury was 12 March 2021.
2. Mr Lutherborrow was employed as a Network Operator when, on 6 February 2018, he was struck on the head by the tines, weighing between 40 or 50kg approximately, of a backhoe, which he was working on. He continued working until 12 March 2021 when he tripped over a garden hose, which caused an increase in the pain in his neck and lower back.
3. There had been intermittent episodes of neck and back pain between the two injury dates.
4. Mr Lutherborrow had previously come to a non-work-related lumbar laminectomy in March of 2017 with Dr Al -Khawaja.
5. Mr Lutherborrow came a C6 vertebrectomy and decompression at the C5/6 and C6/7 together with an anterior fusion from C5 to C7, with Dr Seex on 3 April 2023.
6. The Medical Assessor found there to be an entitlement of 28% WPI, which he divided equally between each injury, issuing a certificate for 14% WPI respectively.
7. He made no deduction pursuant to s 323 of the 1998 Act.

1. The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
2. As a result of that preliminary review, the Appeal Panel determined that it was not necessary for the worker to undergo a further medical examination, notwithstanding that the Medical Assessor had erred. The issue related to the application of s 323 and the relevant evidence was already before the Medical Assessor. A re-examination would not have assisted our deliberations.

1. The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination.

1. The parts of the medical certificate given by the Medical Assessor that are relevant to the appeal are set out, where relevant, in the body of this decision.

1. Both parties made written submissions which have been considered below by the Appeal Panel.

1. The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
2. In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.

1. As we have already indicated, the Medical Assessor found there to be a 28% WPI for the cervical spine condition.
2. At [10a] he explained that the 28% WPI:

"Should be apportioned equally between the 1st and 2nd injury dates described above...That is because the 1st incident described a significant blow to the head in a frank injury at that time, with no preceding symptoms and he continued to have ongoing neck pain from that time up until he had sustained a significant further aggravation at the time of the 2nd injury date that resulted in him having spinal fusion surgery.."

1. At the same point in his MAC the Medical Assessor referred to the opinions of the opposing medical experts, Dr Bentivoglio and Dr Bosanquet, noting that both experts had applied the provisions of s 323. He said:

"...They both reduced the assessed impairment level by 10% to take into account the preexisting changes identified radiologically. However, in my opinion, it would be more reasonable to attribute the impairment equally between the two injury dates, as explained above."

1. In discussing the opinions of the opposing experts at [10c], the Medical Assessor noted, without making any comment, that Dr Bentivoglio had deducted 10%.
2. With regard to Dr Bosenquet's opinion the Medical Assessor said:

"[Dr Bosenquet] also deducted the assessment by 10% because of the significant longstanding previously identified degenerative changes."

1. At [11] the templated question relating to any deduction the following appears:[1]

"11. DEDUCTION (IF ANY) FOR THE PROPORTION OF THE IMPAIRMENT THAT IS DUE TO PREVIOUS INJURY OR PRE-EXISTING CONDITION OR ABNORMALITY There is no deductible proportion, with the earlier long-standing degenerative changes considered a consequence of the 1st and frank injury of 6 February 2018, and not degeneration per se."

1. The appellant employer did not contest the apportionment made by the Medical Assessor, confining its appeal to the failure by the Medical Assessor to make a deduction pursuant to

s 323, which it kindly has set out for us. 2. We were referred to the usual authorities regarding the application of s 323. Cole v Wenaline Pty Ltd_[2]_ was cited accurately as authority for the proposition that there must be evidence that a pre-existing condition contributed to "the impairment "- we assume was a reference to which the baseline WPI. 3. We were then referred to Fire & Rescue NSW v Clinen[3] and the cases cited therein, as authority for the requirement that any deduction had to be supported by evidence, and that assumption would not suffice. The appellant employer cited dicta from Campbell J that there had to be evidence acceptable to an Appeal Panel to actually support any connection between a previous condition and the baseline impairment. 4. We also referred to Vitaz v Westform (NSW) Pty Ltd[4] and Ryder v Sundance Bakehouse[5] as to the requirement that a deduction can be made only if the pre-existing condition had made a difference to the baseline impairment. 5. The appellant employer then referred us to the evidence that was before the Medical Assessor. Firstly we were referred to a CT scan of Mr Lutherborrow's cervical spine dated

10 September 2021[6]. It was submitted that this investigation demonstrated a "significantly degenerative cervical spine." 6. We were referred to a report by Dr Renata Abraszko of 17 September 2021, whose opinion confirmed that the CT scan demonstrated significantly calcified discs and foraminal stenoses. 7. We were further referred to the report of 14 February 2025 by Dr John Bosanquet, the appellant employer's expert witness. Dr Bosanquet, on looking at investigations dated

23 May 2021, concluded that they showed aggravation of "marked degenerative changes." Dr Bosanquet had deducted one third on account of the "significant" pre-existing degenerative changes. 8. We also referred to the report of Dr Neil Cochrane, retained by the employer, who found that there had not been any specific injury. He advised that there was a disc protrusion in the cervical spine of a degenerative nature which had progressed over some period, and which predated the subject work-related event. 9. Associate Professor Kevin Seex, the treating Neurosurgeon, also stated in a report of

2 March 2023, that there was significant disc degeneration. 10. Similarly Dr Peter Bentivoglio for Mr Lutherborrow, stated there were pre-existing degenerative disease which was exacerbated by the work injuries. 11. The appellant employer accordingly submitted that the Medical Assessor had erred in treating the issues of apportionment and deduction pursuant to s 323 as being mutually exclusive. They were separate and co-existing issues. 12. The pre-existing degenerative changes, it was submitted, were a material factor to the outcome in the case. The radiology demonstrated that there was structural compromise in the cervical spine, making it vulnerable to injury. It was submitted that "but for the advanced degenerative condition" the subject injuries would not have produced the same level of impairment, and Mr Lutherborrow would probably have only suffered temporary soft tissue injury. It was the vulnerability caused by the pre-existing degenerative condition that had led to progressive neurological involvement which required decompression and multi-level fusion. It was, the appellant employer argued, that surgery which had given rise to the assessed level of impairment. 13. By failing to apply a deduction in combination with the apportionment made by the Medical Assessor, it was submitted that he had conflated the two inquiries and thus fell into error. Apportionment addresses the division of liability between two compensable injuries, the appellant employer argued, but it did not negate any requirement to deduct that part of the impairment that was properly attributable to a pre-existing condition. 14. The appellant employer then submitted that the statutory assumption of a 10% deduction pursuant to s 323 (2), was plainly at odds with the available evidence. Such an assumption was not invariably to be applied, but rather was a matter for the clinical judgment informed by the evidence before the Medical Assessor. 15. We were referred to Lovelee v Sydney International Container Terminals Pty Ltd[7] where a Medical Panel emphasized the function of the Medical Assessor in determining the deduction (that authority was reversed on other grounds in the Supreme Court). It was submitted that treating and forensic specialists alike all accepted the presence of significant pre-existing degenerative pathology. The appellant employer noted that Dr Bosanquet had in fact made a one-third deduction, stating that 10% was inadequate given the severity of those changes. 16. Accordingly it was submitted that the application of the 10% statutory assumption would not properly reflect the evidence and submitted that Dr Bosanquet's opinion should be accepted.

1. Mr Lutherborrow submitted that the Medical Assessor had in fact considered the question of the deduction pursuant to s 323, as demonstrated by the content of [11] of the MAC, and had justified that opinion by his finding that the degenerative changes were in fact a consequence of the first injury.
2. Mr Lutherborrow submitted that both injuries involved the same pathology and thus the only question was as to apportionment.
3. There was in fact a deduction made, but the Medical Assessor had not used the correct form. Mr Lutherborrow argued that in finding 14% for each injury, the Medical Assessor had in reality made deductions of 50% for each injury, as he had found that that there was 28% whole person impairment, but had deducted 50% in the case of the earlier injury for the effects of the subsequent injury and in the case of the subsequent injury, 50% for the effects of the first injury pursuant to s 323.
4. We referred to Cullen v Woodbrae Holdings Pty Ltd[8] as authority for the accepted proposition that an assessor must be satisfied that any pre-existing condition did in fact pre-exist the injury. It was submitted that no such conclusion could be drawn in the facts of this case. The first evidence of any pre-existing condition it was submitted was not shown until the "MRI scan" of 23 May 2021 which was over three years subsequent to the occurrence of the first injury.
5. Moreover Mr Lutherborrow's evidence was that he had been asymptomatic regarding his neck until the first injury on 6 February 2018.
6. There was, it was submitted, no evidence to support the existence of any degenerative condition prior to 6 February 2018.
7. There was no evidence that there was any degenerative change prior to that date.

1. Section 323 of the 1998 Act provides relevantly:

"(1) In assessing the degree of permanent impairment resulting from an injury, there is to be a deduction for any proportion of the impairment that is due to any previous injury (whether or not it is an injury for which compensation has been paid or is payable under Division 4 of Part 3 of the 1987 Act) or that is due to any pre-existing condition or abnormality.

(2) If the extent of a deduction under this section (or a part of it) will be difficult or costly to determine (because, for example, of the absence of medical evidence), it is to be assumed (for the purpose of avoiding disputation) that the deduction (or the relevant part of it) is 10% of the impairment, unless this assumption is at odds with the available evidence."

1. It is well accepted that there are three steps to be considered in the application of this section. In Cole v Wenaline Pty Ltd[9] Schmidt J held that firstly the level of impairment caused by the subject injury should be assessed. In the present case it was 26% for the lumbar spine, and that assessment has not been challenged. Her Honour said:

"What s 323 required, however, was that the evidence be considered, so that it could be determined, firstly, what the level of impairment after the second injury was. Secondly, whether a proportion of that impairment was due to the first injury. Thirdly, what that proportion was. Undoubtedly in undertaking this exercise, the medical members of an Appeal Panel must utilise their medical judgement, knowledge and experience. Nevertheless, all stages of the statutory exercise must be undertaken in the light of the evidence and without the making of assumptions not provided for by the section."

1. Schmidt J's case concerned a 'previous injury,' and hence her reference to "first injury" and "second injury". In the present case the issue is whether a 'pre-existing condition 'contributed to what Her Honour described as the "second injury," the baseline WPI, as we describe it.
2. The Medical Assessor found that there was no proportion of the baseline WPI that was due to any pre-existing condition, and the appellant employer argued that he fell into error by doing so. It is necessary to consider evidence that was before him, therefore.
3. Mr Lutherborrow made a statement dated 22 December 2021. He stated immediately:

"Prior to 6 February 2018 I was unaware of any problems with my neck at all. However I had a history of issues with my lower back."[10]

1. Mr Lutherborrow explained that he underwent a laminectomy for his back in 2017 and that he thereafter returned to work and was "perfectly fine" with regard to his lumbar spine. He described the work he was doing as arduous:

"Essentially water services work ...includes attending water breaks in relation to supply of water other than private and residential property. A lot of my work is involved in excavating trenches and laying of pipes. I am often working in muddy and tightly confined position[s] and constantly climbing into and out of trenches and carrying and lifting objects including tools of the trade and sections of pipe and earth and rubble. It can be heavy and difficult work [too]".

1. He said on the occasion of the first cervical injury on 6 February 2018 as indicated above he was struck by the tines of a backhoe that weighed between 40 and 50kg which he said "slammed down on to the very top of my head".
2. He said that he was aware of pain all over his head and his neck going down his back as well. Whilst his skull had been the subject of a CT scan, his neck and his lower back were not imaged.
3. He said that he became aware of pain and stiffness that affected his neck which affected him periodically and was worse at times.
4. Dr Peter Bentivoglio, neurosurgeon, retained on behalf of Mr Lutherborrow, reported firstly on 22 June 2022:[11] Dr Bentivoglio noted that the only scans of the cervical spine were dated

"I would have to say that I agree that the work injury initially in February 2018 has certainly exacerbated his neck condition....

I believe the sort of work that [Mr Lutherborrow] has done has contributed to the development of the significant degenerative disc disease and its exacerbation starting back on 6 February 2018..

He undoubtedly has significant pre-existing degenerative disease both in his cervical and lumbar spine and undoubtedly the injury in 2018 and in 2021 have been the main exacerbating and aggravating factors of these problems." [12]

1. He said further at [6] that he believed the original injury of 6 February 2018 exacerbated pre-existing degenerative disease and may have caused the initial disc protrusion at C6/C7. This had slowly but surely deteriorated since that time. Dr Bentivoglio said:

"... Undoubtedly the blow on his head could have caused a flexion injury to his neck and was the start of the worsening of his neck problem"

1. In a supplementary report dated 11 October 2024 Dr Bentivoglio stated[13]:

1. Dr Bentivoglio diagnosed that Mr Lutherborrow had persistent neck pain secondary to multilevel degenerative disease. He said:[14]

"I do believe that he did have some pre-existing degenerative disease which was exacerbated by the work injuries in 2018 and 2021."

"I was not able to see any scarring because he had a beard, but he did have some pre-existing degenerative disease, and I would deduct 10%."

1. Dr Christopher Oates, consultant occupational physician, noted in his report of 10 November 2021[16] that the force of the blow on Mr Lutherborrow's head made it look flattened from its normal shape. Mr Lutherborrow was so concerned because of that shape that he went to Grenfell Hospital and then to Forbes Hospital where the CT scan was taken of his head. He noted that no imaging of the cervical spine was taken until Dr Al-Khawaja, the treating surgeon for Mr Lutherborrow's lumbar spine condition, obtained MRI scans of both the lumbar and cervical areas of the spine on 23 May 2021. He noted that Dr Al -Khawaja was unable to see Mr Lutherborrow and that he saw Dr Renata Abraszko, acting as locum for Dr Al Khawaja. Dr Abraszko obtained a CT scan of the cervical spine on 10 September 2021.
2. Dr Oates recorded that Mr Lutherborrow had not had any previous problems with his neck[17]
3. For the employer Dr John Bosanquet issued a report dated 14 February 2025[18].
4. Dr Bosanquet also recorded that there was no other history of injury to the cervical spine, finding that there had been an aggravation of underlying degenerative changes as a result of the injury on 6 February 2018. He also noted the MRI scan of 23 May 2021, and the CT scan of 10 September 2021 dealing with the cervical spine.
5. Dr Bosanquet said:[19]

"There is a deduction to be made. I have deducted one-third due to the pre-existing degenerative changes."

1. He regarded the 10% deduction made by Dr Bentivoglio on 11 October 2024 to be inadequate.
2. We can thus be satisfied that prior to the injury of 6 February 2018, Mr Lutherborrow had not been aware that he had a degenerative disease in his neck. We note that there were no radiological investigations of the cervical spine prior to 23 May 2021 and that none of the medical specialists gave any reasons as to why they diagnosed that Mr Lutherborrow had a degenerative disease in his cervical spine at the time of the subject 2018 accident. It may be assumed, however, that these diagnoses were based upon the contents of both the MRI scan of 23 May 2021, and the subsequent CT scan of 11 October 2021, being the earliest investigations made of the cervical spine following the injury on 6 February 2018. Subsequent investigations of the cervical spine confirmed the presence of degenerative disease.
3. The MRI scan of Mr Lutheburrow's cervical spine of 23 May 2021 was not before us, however it was consistently reported by the medical specialists. Dr Bosanquet described both the MRI and CT scans as follows:[20]

**"**Cervical spine, 23 May 2021. Comment: Moderate C6/7 spinal canal stenosis due to 4 mm right subarticular disc osteophyte complex. There is moderate bilateral C5/6 foraminal stenosis with potential impingement of the C6 nerve root. There was mild to moderate right C6/7 foraminal narrowing.

CT of the cervical spine, 10 September 2021**.** Conclusion: Spondylotic changes of cervical spine more evidenced at C6/7 with moderate disc osteophytic protrusion and possible marked compression, right C7 nerve root."

1. The CT scan of 10 October 2021 noted:[21]

Intact craniocervical junction. Osteoarthritis of atlanto-axial articulations noted.

There is no remarkable paraspinal soft tissue lesions at the visualised images. CONCLUSION:·

Spondylotlc changes of cervical spine more evident at C6/7 level with moderate disc osteophytic protrusion and possible marked compression right C7 nerve root as described."

1. In Wingfoot Australia Pty Ltd v Kocak,[22] the plurality discussed the function of an Appeal Panel, which comments also apply to a Medical Assessor. At [47] the Court said:

"...The function of a Medical Panel is neither arbitral nor adjudicative: it is neither to choose between competing arguments, nor to opine on the correctness of other opinions on that medical question. The function is in every case to form and to give its own opinion on the medical question referred to it by applying its own medical experience and its own medical expertise."

1. The Medical Assessor had before him the medical opinions that Mr Lutherborrow had aggravated a degenerative disease in his cervical spine at the time of his mishap on

6 February 2018. He did not agree, and neither was he obliged to agree with those opinions. 2. Mr Lutherborrow was asymptomatic at the time of the first injury on 6 February 2018, and the opinions of the medical specialists appear to be based on the first radiological examination, the MRI scan, that was not taken until over three years later, on 23 May 2021. It was indeed possible that the degenerative changes in the neck could have been caused by the mishap of 6 February 2018. 3. That is the conclusion that was reached by the Medical Assessor. He was aware of the opinions of Dr Bentivoglio and Dr Bosanquet but, using his expertise and experience, preferred to diagnose that the asymptomatic cervical spine did not contain any degenerative disease until the shock of the accident. 4. Bearing in mind the severity of the incident of 6 February 2018 when indeed his head was hit with such force that he thought it had been flattened, and X-rays were taken at the hospital only of the skull, it is quite medically consistent that such a severe blow could have started the degenerative problems from which he now suffers. Moreover, Mr Lutherborrow was only 39-years-old at the time of the 2018 accident and at that age it cannot be said that an assumption was available that degenerative changes would probably have been present. 5. Accordingly, it was open to the Medical Assessor to find that the degenerative changes apparent on the radiology, had been caused by the injury of 6 February 2018. 6. Thus, no deduction pursuant to s 323 was applicable. The Medical Assessor found that, as he presented on the day of consultation, Mr Lutherborrow was entitled to 28% WPI, and he explained how that assessment had been calculated. Whilst the surgery of 3 April 2023 followed the second injury on 12 March 2021 when Mr Lutherborrow simply tripped over a garden hose, it was the severity of the first injury of 6 February 2018 that caused the degenerative changes in his cervical spine, and which led to the said surgery. 7. Section 22 of the 1987 Act provides relevantly:

(b) a permanent impairment suffered by a worker as referred to in Division 4 of Part 3, or

(c) a liability under Division 3 of Part 3 to a worker,

results from more than one injury to the worker, liability to pay compensation under this Act is to be apportioned in such manner as the Commission determines."

1. In all circumstances, we find no error in the approach taken by the Medical Assessor. There were two injuries, and the severity of the first injury was a material factor in the requirement for Mr Lutherborrow to undergo cervical surgery following the second injury.
2. For these reasons, the Appeal Panel has determined that the MAC issued on 11 August 2025 should be confirmed.

[2] [2010] NSWSC 78.

[3] [2013] NSWSC 609.

[4] [2011] NSWCA 254.

[5] [2015] NSWSC 526.

[7] [2021] NSWPICMP 179.

[8] [2015] NSWSC 1416.

[9] [2010] NSWSC 78 at [38].

[22] [2013] HCA 43.