1. On 3 March 2025 the appellant, Workers Compensation Nominal Insurer (A.C.N. 147 142 765 Pty Ltd deregistered), lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Alan Home, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 14 February 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 17 December 2024, this matter was referred to the Medical Assessor for an assessment of WPI arising from injury to the left lower extremity and lumbar spine caused by an injury on 2 April 2018.
2. Mr Warner was employed as a removalist offsider when on 2 April 2018 he sustained injuries to his left knee whilst walking up a ramp that tilted and caused him to fall on his left leg.
3. He came to an anterior cruciate ligament reconstruction on 5 February 2019, which was followed by further arthroscopic surgery, and removal of a cyclops lesion on 6 August 2019.
4. Because of his abnormal gait thereafter, he developed low back pain, within six months.
5. He underwent an anterior lumbar interbody fusion at L5/S1 on 23 February 2023.
6. The Medical Assessor found a combined table value of 29% consisting of 22% WPI for the lumbar spine, 8% for the lower extremity and 1% for scarring. He made no deduction in his Table 2 certificate pursuant to s 323, but appeared to have indicated that a deduction should be made for the lumbar spine condition at [11] of the MAC.

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 because the remaining issue raised in this appeal, the provisions of s 323 of the 1998 Act, was dependent on evidence already before the Medical Assessor.

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 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. There are two issues raised in the MAC. The first is conceded by Mr Warner, the respondent, that the 1% WPI rating for scarring should be deleted as it was not the intention of the parties that it be assessed by the Medical Assessor.
2. The remaining ground relates to the application by the Medical Assessor of s 323 of the 1987 Act.
3. After examining the lumbosacral spine and the investigations, the Medical Assessor noted that the claim for the lumbar spine was consequential due to an abnormal gait. He said at [7] of the MAC:[1]

"The worker has undergone a spinal fusion procedure to manage discogenic back pain. The diagnostic imaging demonstrated a focal disc protrusion at L5/S1 but no significant disc disease at the remaining levels.

There was a lateral x-ray of the lumbar spine performed in November 2021, demonstrating mild endplate irregularity in the lumbar spine with preservation of disc space height and no evidence of active endplate or facet joint degeneration.

It is not apparent therefore that the L5/S1 disc pathology occurred against a background of contributory underlying degenerative changes."

1. At [10a] the Medical Assessor found there to be a 22% WPI for the lumbar spine and that a rating was justified by reference to the appropriate guidelines.
2. The Medical Assessor then said:[2]

"I have considered a deduction for underlying degenerative changes. I do not find evidence of degenerative change in the lumbar spine on the initial imaging.

Whilst I note that Dr Powell made a significant deduction of three quarters due to what he perceived as a contribution of underlying degenerative change. I do not find there is evidence of significant underlying degenerative change prior to the workplace knee injury. [sic]

1. Whilst considering the opinions of other medical practitioners within the evidence before him, the Medical Assessor noted that Dr Khong had not made any deduction pursuant to s 323. He said:[3]

"The report of Dr Khong opined that there should be no deduction made as the worker was a furniture removalist for 15 years. He opined that the heavy and repetitive nature of the work life caused an acceleration of degenerative changes which were asymptomatic. After the knee injury, altered weight bearing caused an exacerbation of the degenerative changes leading to persistent lower back pain.

Again, I do not find evidence on the imaging of any significant underlying degenerative

1. At [11] the Medical Assessor found that there was a pre-existing condition being "asymptomatic arthritis at L5/S1". He said:[4]

"I find that the underlying condition contributed to the development of back pain due to the abnormal gait arising from the left knee injury.

The extent of the deduction is difficult or costly to determine so in applying the provisions of s.323(2) I assess the deductible proportion as one tenth. This is not at odds with available evidence."

1. The appellant employer referred to the comments made by the Medical Assessor regarding the lumbar spine condition. At [10a] he did not find evidence of significant underlying degenerative change but at [11] he found that the underlying condition contributed to the development of back pain and that a one tenth deduction should be made.
2. We were referred to Cole v Wenaline Pty Ltd[5] in support of the unremarkable submission that a deduction can be made even where the condition was asymptomatic prior to the subject injury.
3. The error, it was submitted, was that he neglected to include the 1/10th deduction in the Table 2 Certificate.

1. Mr Warner did not engage with the submission that the Medical Assessor had appeared to contradict himself by his comments. Mr Warner submitted that the appellant employer's submission was "misconceived" and raised three matters in support thereof. These will be dealt with in the following discussion.
2. Mr Warner concluded by submitting that against the background of minor radiological findings, it was open to the Medical Assessor to make no deduction under s 323.

"323 Deduction for previous injury or pre-existing condition or abnormality

(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. The three factors relied on by Mr Warner were firstly that his back had been asymptomatic prior to the subject knee injury. This is not in dispute.
2. The second submission related to a report by the appellant employer's medical expert,

Dr Richard Powell, dated 8 May 2024 in which Dr Powell allegedly described an MRI scan of the lumbar spine dated 18 December 2020 as revealing "minor" degenerative change. This is not wholly accurate, with respect. Dr Powell did not refer to the 18 December 2020 MRI scan at all in his report of 8 May 2024, although he acknowledged it in an earlier report dated 12 April 2021. He in fact said that the results of the 2020 scan reported a "normal" lumbar spine.[6] 3. In his report of 8 May 2024, Dr Powell did make reference to "minor degenerative changes," but that was in reference to the left knee condition.[7] In this report, Dr Powell had available six investigations for review, dating from 7 July 2022 to 26 February 2024.[8] Five of these related to the lumbar spine. In his diagnosis as to the lumbar spine he said relevantly:[9]

".... Investigations revealed evidence of minor L5/S1 disc lesion...."

1. Mr Warner also referred to the Medical Assessor's summary at [7] of the MAC, which we have reproduced above. Mr Warner relied upon the Medical Assessor's statement that the L5/S1 disc pathology did not occur against a background of contributory underlying degenerative changes. Mr Warner submitted therefore that, within the terminology of s 323, the Medical Assessor had found that the pre-existing lumbar condition was "not a contributing factor."
2. The third factual matter raised by Mr Warner was that he was only 37 years of age at the time of the accident and had been working as a furniture removalist for various employers without any lumbar complaint since 2002.
3. The submissions by Mr Warner did not engage directly with the point raised by the appellant employer, that the Medical Assessor appears to have made a typographical error in either recording at [11c] that there was a deductible proportion of one tenth, or recording in his Table 2 Certificate that no deduction was called for. It is clear however that Mr Warner supported the proposition that the error lay in what was recorded at [11c].
4. The Medical Assessor said in his diagnosis that the lateral X-ray of the lumbar spine in 2021 showed open "mild endplate irregularity in the lumbar spine with preservation of disc space height and no evidence of active endplate facet joint degeneration." [10] His comment that "it is not apparent therefore, that the L5/S1 disc pathology occurred against the background of contributory underlying degenerative changes" is a clear finding that there was no contribution to the baseline impairment from any pre-existing degenerative changes.
5. He repeated that opinion having dealt with Dr Khong's report - namely that he did not find evidence on the imaging of "any significant underlying degenerative change."
6. This evidence makes the content of [11] of the MAC difficult to comprehend. There is no support for a diagnosis of "pre-existing asymptomatic arthritis at L5/S1" which is recorded at [11a(i)]. Similarly, the finding that the pre-existing asymptomatic arthritic condition "contributed to the development of back pain due to the abnormal gait arising from the left knee injury" does not correlate with the evidence that was before the Medical Assessor. There was no suggestion in the investigations that Mr Warner was suffering from a pre-existing arthritic condition. Indeed, the Medical Assessor emphasised in his diagnosis at [7] that, to repeat:

"It is not apparent therefore, that the L5/S1 disc pathology occurred against the background of contributory underlying degenerative changes."

1. The solution to this typographical puzzle is that the contents of [11] may well inadvertently relate to another similar case. The template for this paragraph is somewhat confusing, and we note that the template for [11c] states:

"The extent of the deduction is difficult or costly to determine so in applying the provisions of s 323(2)ISS the deductible proportion as one tenth. (can only be used when not at odds with available evidence.)"

1. The possibility that a determination of a one tenth deduction might inadvertently be included because of that wording cannot be discounted.
2. Thus, we find the Table 2 certificate to accurately reflect the Medical Assessor's determination. The MAC will be revoked to delete the award for scarring.
3. For these reasons, the Appeal Panel has determined that the MAC issued on

14 February 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 Alan Home, 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)

[5] [2010] NSWSC 78.