1. This, it was argued, established that the employer had accepted liability for the surgery, and that therefore the decision by the Medical Assessor that the surgery was unrelated to the subject injury could not stand. The consent orders gave "procedural and evidentiary context for the referral," it was said.
2. We have some doubts about that argument. Employers, through their insurers, often resolve claims within the Commission in the manner illustrated above. The parties on 2 April 2024 were prepared to accept a compromise that the insurer would meet the cost of the surgery, but recording that it did so on a voluntary basis in a note to the Order had the effect of leaving the question of liability in abeyance.
3. This ground fails.

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. In Donhad Pty Ltd v Asbury[5] Griffiths JA summarised the relevant authority regarding the application of s 323, from [52]:

"52. The task of a medical assessor under s 323 was described by Schmidt J in Cole at [38]:

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 judgment, knowledge and experience. Nevertheless, all stages of the statutory exercise must be taken in the light of the evidence and without the making of assumptions not provided for by the section.

1. Earlier in the reasons for judgment in Cole, her Honour made the following observations regarding s 323 (emphasis added):
   1. ... The section is directed to a situation where there is a pre-existing injury, pre-existing condition or abnormality. For a deduction to be made from what has been assessed to have been the level of impairment which resulted from the later injury in question, a conclusion is required, on the evidence, that the pre-existing injury, pre-existing condition or abnormality caused or contributed to that impairment.

30. Section 323 does not permit that assessment to be made on the basis of an assumption or hypothesis, that once a particular injury has occurred, it will always, 'irrespective of outcome', contribute to the impairment flowing from any subsequent injury. The assessment must have regard to the evidence as to the actual consequences of the earlier injury, pre-existing condition or abnormality. The extent that the later impairment was due to the earlier injury, pre-existing condition or abnormality must be determined. The only exception is that provided for in s 323(2), where the required deduction 'will be difficult or costly to determine (because, for example, of the absence of medical evidence)'. In that case, an assumption is provided for, namely that the deduction 'is 10% of the impairment'. Even then, that assumption is displaced, if it is at odds with the available evidence

1. ... Section 323 requires that a conclusion be reached as to whether or not any proportion of permanent impairment assessed resulted from an earlier injury, pre-existing condition or abnormality. In a case such as this, that conclusion must be reached on the evidence led as to the actual consequences of the earlier and later injuries, unless the assumption provided in s 323(2) applies.
2. This approach was endorsed and explained by Campbell J in Ryder v Sundance Bakehouse [2015] NSWSC 526 at [45] (emphasis added):

'What s 323 requires is an inquiry into whether there are other causes, (previous injury, or pre-existing abnormality), of an impairment caused by a work injury. A proportion of the impairment would be due to the pre-existing abnormality (even if that proportion cannot be precisely identified without difficulty or expense) only if it can be said that the pre-existing abnormality made a difference to the outcome in terms of the degree of impairment resulting from the work injury. If there is no difference in outcome, that is to say, if the degree of impairment is not greater than it would otherwise have been as a result of the injury, it is impossible to say that a proportion of it is due to the pre-existing abnormality. To put it another way, the Panel must be satisfied that but for the pre-existing abnormality, the degree of impairment resulting from the work injury would not have been as great.'

1. Finally, it is desirable to note the following observations by Wright J in Southwell at [49]-[50] which also approve the approach in Cole:

'49. On its terms, however, s 323(2) does not apply if it has not been determined that a deduction is to be made under subs (1) because a part or portion of the level of impairment suffered was due to the pre-existing condition. Subsection (2) relates only to 'the extent of a deduction under this section' not to whether such a deduction is required. As Schmidt J held, in effect, in Cole v Wenaline Pty Ltd [2010] NSWSC 78 (Cole) at [30] and [31], s 323(1) does not permit the assessment of whether a deduction is required to be made on the basis of an assumption or hypothesis, that once there is found to be a particular pre-existing condition, it will always, 'irrespective of outcome', contribute to the impairment flowing from any subsequent injury. Rather, the assessment of whether a deduction is required must have regard to the evidence as to the actual consequences of the pre-existing condition and whether any proportion of the permanent impairment present after the workplace injury was due to the pre-existing condition.

50. Thus, it has been held, in cases such as Elcheikh v Diamond Formwork (NSW) Pty Ltd (in liq) [2013] NSWSC 365 at [126] (Schmidt J) and Secretary, Department of Communities and Justice v Lewandowski [2023] NSWSC 334 at [52] (Griffith AJ), that what must be determined under s 323 involves, at least, three enquiries:

• Firstly, what the extent of the resulting impairment is.
• Secondly, whether the pre-existing condition contributed to the impairment.
• Thirdly, if it did, what proportion of the impairment was due to the pre-existing condition."

1. The first enquiry - which we have referred to as the baseline impairment - was assessed at 26%. It has been challenged on peripheral grounds but for present purposes a baseline assessment of 26% WPI may be accepted.
2. The second and third enquiries however are more problematic, and require an examination of the evidence.
3. Ms Greening made her first statement on 27 February 2024.[6] She stated that she commenced work with the respondent on 16 July 2015. At [7] she described the nature of her duties as a retail sales assistant which involved a significant amount of heavy lifting, pushing and pulling large furniture, bending to assemble bed frames, dismantling bed frames, pulling down king mattresses onto a handmade wooden trolley with no brakes. The delivery men would simply unload the truck and leave the stock stacked on the handmade wooden trolley.
4. At [18] she did not describe the onset of her symptoms but simply said that she went to see a general practitioner (GP) on 24 September 2019 and complained of hurting her back the day before.
5. The statement thereafter was really a chronology of her medical treatment and appeared to be made for the purpose of supporting Ms Greening's application to have the insurer approve the cervical spinal surgery which resulted in the consent orders of 2 April 2024.
6. However, the chronology did demonstrate that Ms Greening's initial complaint was of injury to the lumbar spine, which was investigated by MRI scan on 30 September 2019. On 25 October 2019 Ms Greening complained of pain in the middle of her spine, and an MRI scan was taken of the thoracic spine on 2 December 2019. Exacerbations of Ms Greening's back condition were reported on 27 August 2020 and 3 September 2020 whilst she was back at work.
7. Ms Greening ceased work on about 9 September 2020, and a further MRI of the lumbar spine was carried out on 29 September 2020. Further investigations and treatment were performed regarding the thoracic spine and at [44] Ms Greening first mentioned her neck on 28 January 2021. An MRI scan of the neck was carried out on 12 March 2021.
8. Ms Greening returned to work on light duties on 24 June 2021 and she underwent pain management until on 18 March 2023 a further MRI scan of her neck was performed.
9. It is not clear that this statement was comprehensive, as Dr Coughlan, the treating surgeon first made mention of the neck condition on 11 November 2022,[7] notwithstanding that he had been treating her for both her lumbar and thoracic symptoms since 8 April 2020.
10. Dr Courtenay. Ms Greening's qualified expert, took a history on 3 August 2023 that Ms Greening had been experiencing cervical spine problems for "the past 12 months."[8] His supplementary report of 1 February 2024 advised the cervical spine surgery was indicated in view of the relief that injections gave her[9] and in his final opinion of 5 March 2025 he said:[10]

"Ms Greening has certainly had improvement following the C5/6 fusion and decompression. She does have some problems at other levels and there is an underlying general pre-existing condition, leading her to developing more spondylosis and I certainly do acknowledge that.

However, from her history, Ms Greening did a lot of physical activity. She did tenpin bowling, she worked for Sleeping Giant where she had to carry beds and move them and put them on trolleys and do a lot of other heavy physical activity and she has no history of any other pre-existing symptoms into her neck, other than one short episode which never led to anything.

Therefore, I certainly do acknowledge the pre-existing (sic), but I also acknowledge that she has had significant improvement in her symptoms from that surgery."

1. Dr Bosanquet, qualified by the employer, gave a history on 20 November 2024 that Ms Greening had experienced low back pain at the time of the subject injury on 24 September 2019, but that "she then, without a triggering factor, developed pain in her cervical spine in mid-2022..."[11]
2. His opinion was:

"Anne Greening is a 55-year-old woman who worked at the Sleeping Giant in retail. She sustained an injury to her thoracolumbar spine on 24/09/19 with aggravation of pre-existing degenerative changes on a background of DISH syndrome. She has also developed pain in her neck with aggravation of pre-existing degenerative changes for which a C5-6 anterior cervical decompression and fusion has been carried out."

1. There is some minor inconsistency as to when Ms Greening first experienced symptoms in her cervical spine, as both medico-legal experts nominated some time in 2022, whereas the first complaint mentioned in Ms Greening's statement was in January 2021. It can be seen therefore that she did not injure her cervical spine in the episode of 24 September 2019, but rather that her symptoms developed some time later, on a background of degenerative change, which was common ground.
2. The respondent accepted liability for Ms Greening's injury on the basis that the frank injury to the lumbar spine on 24 September 2019 had also aggravated her cervical spine, as no demur was made to the claimed injury date.
3. The difficulty facing the Medical Assessor was accordingly to quantify the contribution made to the baseline assessment by Ms Greening's pre-existing degenerative condition. This problem was considered in Elcheikh, referred to by the respondent.
4. Mr Elcheikh had been born in 1970 and been working as a labourer (and subsequently, a leading hand) since 1990. His deemed date of injury was 1 January 2007, although he began experiencing symptoms in 2004, but worked on until 2008, when the employer went into liquidation. The Medical Assessor deducted 50% from the baseline impairment, which had benefitted from the increased impairment assessment for surgery provided by AMA 5 and the Guides.
5. Schmidt J said at [104]:

"The Appeal Panel approached what it had to determine by adopting what the medical specialist had asked himself as to whether the underlying condition was a necessary factor in the decision to carry out the surgery undertaken in 2010. He concluded that it was, observing that 'if not for the underlying Scheuermann's disease, there is no way that surgery would have even been considered'. If this was a relevant consideration in the factual circumstances, what clearly also required consideration, given that the condition had been asymptomatic, was whether, without the impact of his heavy work the pre-existing condition would have required such surgery."

"...The legislative scheme required the medical specialist to determine Mr Elcheikh's deductible proportion, not by reference to his workplace injury, but rather by determining what contribution the pre-existing condition had made to the permanent impairment which had resulted from that injury."

1. The Medical Assessor has made the same error in the present case. It is not the fact that Ms Greening required surgical treatment, nor the fact that the surgical treatment has resulted in significantly increased entitlements, that is relevant in the assessment process. The relevant fact is that Ms Greening was injured by the work she was required to do for the respondent. Without having to do that arduous work, she may well never have aggravated her underlying condition. She was asymptomatic prior to her injury, and she had been active in her sporting field of ten pin bowling. She would no doubt have preferred not to have to endure the surgical procedure she underwent, but because of her injury she was not left with much choice. What benefit a claimant is entitled to is not a relevant consideration in the assessment process. The second enquiry is simply concerned with whether any prior injury, or pre-existing condition or abnormality contributed to the baseline impairment.
2. The third enquiry relates to the quantum of the deduction, bearing in mind our above findings. As we have noted, Ms Greening was asymptomatic at the time of her injury. She was active and fully employed when she suffered her injury. Consequently, there is a dearth of medical evidence about her degenerative condition prior to 24 September 2019, and its extent is speculative, based as it is on intensive investigation that post-dated her injury. In that regard we note that the first MRI investigation of the cervical spine did not occur until 12 March 2021, after she had been investigated for other spinal complaints, and the appearance on that scan and subsequent investigations make the extent of the deduction difficult to determine, as the degenerative condition therein shown may have deteriorated or accelerated since 24 September 2019. The statutory assumption of 10% afforded by s 323(2) is accordingly the appropriate deduction.
3. For these reasons, the MAC will be revoked.

1. We note Ms Greening's submissions regarding these modifiers. The modifiers for both the increments for the restrictions in daily living set out in Chapter 4.33 and following in the Guides, and for scarring pursuant Chapter 14.8 of the Guides are discretionary, and we find no error in the assessment, or the clarity of the reasons for them. They depended on the Medical Assessor's clinical judgement, and whilst other minds might differ, no error of fact has been demonstrated.
2. This ground is dismissed.
3. For these reasons, the Appeal Panel has determined that the MAC issued on 13 August 2025 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act 1998.

The Appeal Panel revokes the Medical Assessment Certificate of Medical Assessor Rob Kuru and issues this new Medical Assessment Certificate as to the matters set out in the table below:

Chapter, page and paragraph number in NSW workers compensation guidelines

Chapter, page, paragraph, figure and table numbers in AMA 5 Guides

Proportion of permanent impairment due to pre-existing injury, abnormality or condition

Sub-total/s % WPI (after any deductions in column 6)

Total % WPI (the Combined Table values of all sub-totals)

[1] [2013] NSWSC 365.

[2] [2010] NSWSC 78.

[3] [2015] NSWSC 526.

[4] Skates v Hills Industries Ltd [2021] NSWCA 142.

[5] [2025] NSWSC 1548.