1. On 10 March 2025 Margaret Cutajar (the appellant) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Tommasino Mastroianni, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on

11 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 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 Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5).

1. The appellant suffered an injury on 3 December 2021 in her employment as a canteen supervisor with Figtree High School P & C Association (the respondent).
2. The appellant lodged an Application to Resolve a Dispute in the Personal Injury Commission (Commission) dated 19 November 2024 in which she claimed lump sum compensation in respect the injury to her lumbar spine, left lower extremity and scarring.
3. The matter was referred to Dr Tommasino Mastroianni, Medical Assessor, for assessment of whole person impairment (WPI) of the lumbar spine and scarring/TEMSKI as a result of the injury on 3 December 2021.
4. The Medical Assessor examined the appellant on 5 February 2025 and assessed 16% WPI in respect of the injury to the lumbar spine and 0% WPI in relation to scarring (TEMSKI). The Medical Assessor deducted one tenth pursuant to s 323 of the 1998 Act, which resulted in an assessment of 14% WPI as a result of the injury on 3 December 2021.

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 there was sufficient information upon which to make a determination.

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. They are not repeated in full, but have been considered by the Appeal Panel.
2. The appellant's submissions include the following:

(a) Ground 1 - The Medical Assessor failed to assess and failed to find rateable pathology in relation to scarring.

(b) Although it can be argued that it is a matter for clinical assessment, ultimately the guides are statutory in nature; Elsworthy v Forgacs Engineering Pty Ltd [2018] NSWSC 1638. If they are wrongly applied, it is an error of law.

(c) Scarring is governed by the Table for the evaluation of minor skin impairment (TEMSKI), Table 14.1 of the Guidelines. The Medical Assessor noted a history that "she is very conscious of the scar". Consciousness of the scar is the first consideration in the third column of Table 14.1 which attracts 1% WPI, as compared with the second column which starts with matters in which a claimant is not conscious or barely conscious of the scar (which attracts 0% WPI).

(d) Ground 2 - The Medical Assessor made a deduction under s 323 that was not open.

(e) A deduction for pre-existing pathology at the rate of 10% is only available where it is "difficult or costly to determine" to determine. Other that stating the test, the Medical Assessor did not appear to actually find this to be so. If he did, there are no reasons.

(f) The threshold for a 10% deduction in lieu of a properly reasoned deduction based on clinical expertise does not arise unless a Medical Assessor finds the "difficult or costly" threshold to arise, and to say why.

(g) Ground 3 - The Medical Assessor failed to give adequate reasons.

(h) The 10% deduction contemplated by s 323 is not presumptive or default. It is the opposite. It only arises where a properly reasoned deduction cannot be made, namely because it would be "difficult or costly to determine" in the ordinary way. No reasons are given why the 10% discount applied as opposed to an actually reasoned out discount.

(i) Rather, at cl 11 the Medical Assessor simply states that he proposes to apply s 323(2) with no reasons.

(j) In relation to scarring, whilst the Medical Assessor briefly notes (at 10c) that

Dr Bodel found pigmentation, the Medical Assessor simply says he found no pigmentation. The existence or non-existence of pigmentation is a fairly significant difference. Why pigmentation might be present one day and not the next has not been explained. Whilst it is accepted that the Medical Assessor had to assess the worker as he found her on the day, it was also necessary to explain why his conclusions different - not merely to state the existence of different opinions.

(k) The MAC should be set aside and, in lieu thereof, WPI reassessed by the Panel.

1. The respondent's submissions include the following:

(a) Ground 1 - failure to Assess Scarring - it is a matter for the Medical Assessor's clinical judgement to determine if an assessment for scarring was warranted.

(b) The Medical Assessor stated in the MAC that whilst the appellant is very conscious of the scar, there is a good colour match with the surrounding skin, there are no trophic changes, no suture marks, the location is not clearly visible with usual clothing, no contour defect, no effect of ADL's, no treatment require and no adherence. As such, he utilised the best fit principle under the TEMSKI classification.

(c) The best fit principle in the Guidelines state that a medical examiner should assess the whole skin system against each criterion and then determine which impairment category best fits or describes the impairment.

(d) Based on this principle, the respondent acknowledges that the appellant is "very conscious of the scar" however, based on the other criteria assessed, which supported an assessment of 0% WPI, the Medical Assessor utilised his professional opinion and applied the assessment with the best fit, which was 0% WPI for scarring. This was open to him based on his findings on examination.

(e) Further, it is well established that the Medical Assessor is not bound to accept the assessments given by other assessors. Instead, the Medical Assessor is required to undertake their assessment on the basis of the worker's presentation on the day (see cl 1.6(a) of the Guidelines). Further, in Parker v Select Civil Pty Ltd [2018] NSWSC 140, it was found that a difference in opinion was insufficient to amount to a demonstrable error or incorrect criteria for the purposes of s 327(3) of the Act.

(f) Ground 2- Section 323 Deduction - the action of the Medical Assessor applying the 1/10th deduction for the pre-existing condition is self-explanatory and does not require extensive reasons. He applied this deduction based on the Guidelines which state "for the injury being assessed, the deduction is 1/10th of the assessed impairment, unless that is at odds with the available evidence".

(g) The Medical Assessor reported that the appellant suffered an aggravation of pre-existing lumbar spondylosis (Page 4 of the MAC) and there was evidence of underlying degenerative disease of the lumbar spine with a history of a back injury which left her with intermittent back pain (Page 6 of the MAC). He considered that the persistent symptoms related to the work injury and the underlying degenerative disease and was of the opinion that the pre-existing degenerative disease is a component of the current impairment (Page 6 of the MAC).

(h) It was open to the Medical Assessor to apply the one tenth deduction as that was the deduction he considered to be appropriate based on the clinical picture available to him and his own examination. As such, this is not a demonstrable error nor is the lack of reasons an error as the Guidelines set the circumstances in which this deduction is to be applied and is a well-known standard deduction.

(i) Further, in Merza v Registrar of the Workers Compensation Commission [2006] NSWC 939, Hoeben J stated that a "demonstrable error" is an error which is readily apparent from an examination of the medical assessment certificate and the document referring the matter to the AMS for assessment. Hoeben J also stated that a "demonstrable error" would essentially be an error where there is no information or material to support the finding made rather than a difference of opinion. In this matter, the Medical Assessor clearly diagnoses an aggravation of a pre-existing condition in the lumbar spine and applied a one tenth deduction for same, which is the standard procedure as per the Guidelines.

(j) The Medical Assessor not addressing the specific issue of "difficult or costly to apply a deduction," does not form the basis for an appeal under s 327(3)(c) as this does not fall within the meaning of demonstrable error as noted in Merza.

(k) Ground 3 - failure to provide adequate reasons - the Medical Assessor has provided sufficient reasons on page 6 of the MAC as to why he considered that a one tenth deduction was warranted and any other deduction would be difficult or costly to determine, thus he applied the standard one tenth deduction under s 323.

(l) The appellant also states that Dr Bodel found pigmentation in the scarring, whereas the Medical Assessor found no pigmentation and there has been no explanation for same. They say that it is necessary for the Medical Assessor to explain why his conclusions are different and not state the existence of different opinions.

(m) The obligation of the Medical Assessor to explain his or her assessment requires them to reveal the actual path of reasoning by which they arrived at their opinion in sufficient detail such that an Appeal Panel can ascertain whether there is any error in the reasoning. This obligation does not require the Medical Assessor to explain why they did or did not form an opinion, even if that opinion differs from those of other examiners.

(n) The Medical Assessor is also not required to choose between competing medical opinions put forward by the parties (in accordance with Wingfoot Aust Partners Pty Ltd v Cocak [2013] HCA 43 and State of New South Wales (NSW Department of Education) v Kaur [2016] NSWSC 346). The Medical Assessor stating that he found no pigmentation is an explanation in itself and no further explanation is required for same, noting it is merely a description of the scar's appearance. The Medical Assessor also set out in detail in the body of the MAC his examination of the scarring, which formed the basis of the assessment of 0% WPI for scarring.

(o) The Medical Assessor is also not required to explain why his conclusions are different to either IME in respect of scarring noting that he has based his assessment on the clinical picture assessed by him in February 2025 compared to Dr Bodel's assessment in August 2023 and Dr Deshpande in February 2024.

(p) The above comments show that the Medical Assessor turned his mind to the question of whether there was any impairment resulted from the scarring and whether a deduction for the preexisting condition was required, and that he used his clinical judgement as well as the available evidence to determine that both were applicable in this matter.

(q) Having regard to the whole report and the statement of the Medical Assessor that he utilised his own examination to justify his assessment, the Medical Assessor has not failed to provide reasons to justify his assessment in respect of scarring or the s 323 deduction.

(r) The MAC should be confirmed.

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.
3. The Appeal Panel reviewed the history recorded by the Medical Assessor, his findings on examination, and the reasons for his conclusions as well as the evidence referred to above.

1. The appellant submits that the Medical Assessor has incorrectly applied the SIRA Guidelines by not assessing scarring and that this is an error of law.
2. Under "Present symptoms" the Medical Assessor noted: "When I examined her back and measured the scar, she said she does not like having the scar and later said she is very conscious of the scar."
3. Under "Findings on physical examination" the Medical Assessor wrote:

"Examination of the back reveals normal spinal curve. There is a 5cm scar over the L3/4, L4/5 level. It is a fine pale scar. There was no pigmentation, no trophic changes and suture marks were not visible. There was no tethering".

1. Under "Reasons for Assessment" at part 10 a of the MAC, the Medical Assessor wrote:

"The claimant has a scar in the back which in my opinion best fits the descriptors for 0% WPI under the best fit principle of the TEMSKI classification. She states that she is very conscious of the scar, there is good colour match with the surrounding skin, there are no trophic changes, I could not see any suture marks, the location of the scar is not clearly visible with usual clothing, there is no contour defect, no effect on ADLs, no treatment is required and there is no adherence".

1. In commenting on the other medical opinions at Part 10 c of the MAC, the Medical Assessor wrote: "Dr Bodel assesses 1% WPI for scarring, and on examination he said the scar is slightly pigmented. I found no pigmentation. I assessed 0% WPI (see 10a)."
2. Dr James Bodel, consultant orthopaedic surgeon, in his report dated 24 August 2023 noted on examination: "There is a healed midline scar which I rate as a 1% Whole Person Impairment under the TEMSKI scale. It is slightly pigmented. It is tender to touch and is irritated by tight clothing. It is not tethered to underlying deep structures".
3. Dr Bodel assessed 1% WPI for scarring and wrote: "The only other rating is the scarring, and as I have indicated above, the scar is rated as a 1% Whole Person Impairment under the TEMSKI scale for the reasons I outlined in the 'Examination' section".
4. Dr Sham Rao Deshpande, consultant orthopaedic surgeon, in his report dated 28 February 2024 noted: "Spine: A 6cm long scar which is well healed, not sensitive, and no discolouration." He also wrote: "Her scar is hardly visible and has no discolouration or increased sensitivity". Dr Deshpande made no assessment for scarring.
5. Paragraph 14.8 of the Guidelines provides:

"The TEMSKI is to be used in accordance with the principle of 'best fit'. The assessor must be satisfied that the criteria within the chosen category of impairment best reflect the skin disorder being assessed. If the skin disorder does not meet all of the criteria within the impairment category, the assessor must provide detailed reasons as to why this category has been chosen over other categories."

1. The Appeal Panel noted that the Medical Assessor had considered and made findings in respect of all of the criteria in Table 14.1 of the Guidelines. Table 14.1 uses the principle of "best fit" and the Appeal Panel was satisfied that the Medical Assessor assessed impairment of the whole skin system against each criterion and then determined which impairment category best fits, that being 0% WPI.
2. The Medical Assessor noted that the appellant had a scar on her back and she stated that she was very conscious of the scar. However, the Medical Assessor found that there was good colour match with the surrounding skin, no trophic changes, no visible suture marks, the location of the scar was not clearly visible with usual clothing, there was no contour defect, no effect on ADLs, no treatment was required and there was no adherence.
3. The Appeal Panel considered that the Medical Assessor applied the principle of "best fit" and apart from finding that the appellant was very conscious of the scar, found based on the other criteria assessed, the "best fit" supported an assessment of 0% WPI. In so doing, the Medical Assessor utilised his professional opinion this assessment was open to him based on his findings on examination.
4. The findings on examination by the Medical Assessor were, in the view of the Appeal Panel, inconsistent with a 1% impairment category in Table 14.1.
5. The Appeal Panel considered that the Medical Assessor provided sufficiently detailed reasons for why this category was chosen over other categories. The Medical Assessor provided a very clear description of the scar in the lower back region and had considered the various factors that he was required to take into account in making his assessment.
6. Dr Bodel noted on examination slightly pigmentation of the scar. However, Dr Bodel's examination was in August 2023, some 15 months after the appellant's surgery to her lumbar spine on 25 May 2022. Likely scar improved since that assessment and the Medical Assessor found no pigmentation.
7. The Appeal Panel finds that the Medical Assessor made no error in respect of the assessment of scarring. This ground of appeal is not made out.

1. The appellant submits that the Medical Assessor does not provide sufficient reasons to justify his 1/10th deduction for the pre-existing condition in the lumbar spine and why it was "difficult or costly to apply a deduction".
2. The Guidelines at Part 2 under "Deductions for pre-existing conditions or injuries" at Guidelines 1.27 and 1.28 provide:

"1.27 The degree of permanent impairment resulting from pre-existing impairments should not be included in the final calculation of permanent impairment if those impairments are not related to the compensable injury. The assessor needs to take account of all available evidence to calculate the degree of permanent impairment that pre-existed the injury.

1.28 In assessing the degree of permanent impairment resulting from the compensable injury/condition, the assessor is to indicate the degree of impairment due to any previous injury, pre-existing condition or abnormality. This proportion is known as 'the deductible proportion' and should be deducted from the degree of permanent impairment determined by the assessor. For the injury being assessed, the deduction is 1/10th of the assessed impairment, unless that is at odds with the available evidence."

"(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.

Note. So if the degree of permanent impairment is assessed as 30% and subsection (2) operates to require a 10% reduction in that impairment to be assumed, the degree of permanent impairment is reduced from 30% to 27% (a reduction of 10%).

(3) The reference in subsection (2) to medical evidence is a reference to medical evidence accepted or preferred by the medical assessor in connection with the medical assessment of the matter.

(4) The WorkCover Guidelines may make provision for or with respect to the determination of the deduction required by this section."

1. The approach to be taken in assessing the s 323 deduction was considered by the Supreme Court in Cole v Wenaline Pty Ltd (2010) NSWSC 78 (Cole). Schmidt J said:

"29 ... 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.

1. 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.
2. The reason for this statutory approach can readily be seen. It is entirely possible that a person could suffer such a catastrophic injury, that the presence or absence of any previous injury, pre-existing condition or abnormality, would make no difference at all to the impairment which resulted from the later injury. An injury which results in death, is an obvious example, albeit not one which would arise for consideration under this section. A more relevant example, in this case, is a second injury which severed the spine. Or, as was discussed in the authorities, an earlier injury which was asymptomatic, may or may not contribute to the impairment which results from a second injury. That is a matter of fact to be assessed on the evidence led in each case. An assumption of the kind here made, namely that surgery to the lumber spine, irrespective of outcome, must always result in a level of residual impairment which contributes to the level of impairment which follows a later injury, has no role to play in that assessment. What must be determined on the evidence is whether any proportion of the permanent impairment present after the second injury was due to the earlier injury."
3. The Appeal Panel reviewed the evidence in this matter.
4. The Medical Assessor noted under "Details of any previous or subsequent accidents, injuries or condition" the appellant said that "she has always had back pain". He wrote:

"She said that she had a motor vehicle accident some 20 years ago and has had back pain on and off since. She said that she has had intermittent back pain usually related to activities. For the back pain she would take over-the-counter medication."

1. The Medical Assessor noted that in the MRI scan report dated 12 July 2021, Dr Adewumi reported multilevel disc degeneration and bulge.
2. Under "Summary of injuries and diagnoses" the Medical Assessor wrote:

"The claimant sustained a disc lesion and aggravated pre-existing lumbar spondylosis. She developed sciatica post-injury and she had surgery on 8 June 2022. She had bilateral L3/4 and L4/5 laminotomy and foraminotomy, rhyzolysis and left L4/5 micro lumbar discectomy."

1. In Part 8 of the MAC, the Medical Assessor wrote:

"e. Is any proportion of loss of efficient use or impairment or whole person impairment, due to a previous injury, pre-existing condition or abnormality? Yes

f. If so, please indicate which body part/system is affected by the previous injury, pre-existing condition or abnormality. Lumbar spine."

1. Under "Reasons for Assessment" the Medical Assessor wrote:

"The claimant has a history of back pain which in my opinion contributed to the need for surgery and for the persisting symptoms. Being guided by the history of intermittent back pain for some 20 years, the radiology at the time of the examination and the need for a cortisone injection to the facet joint post op. I have deducted one-tenth for her pre-existing condition applying the provision of section 323. This equates to 1.6% WPI. The claimant therefore has 14.4% WPI which rounds off to 14%."

1. In commenting on the other medical opinions, the Medical Assessor noted that Dr Bodel made no deduction for pre-existing condition and wrote: "In my opinion a deduction is applicable for pre-existing condition (see 10a)". The Medical Assessor commented on

Dr Deshpande's report and wrote: "I agree with Dr Deshpande that a deduction is applicable for pre-existing condition". 2. At part 11 of the MAC, the Medical Assessor wrote:

"The worker has evidence of underlying degenerative disease of the lumbar spine, and a past history of back injury which left her with intermittent back pain. In my opinion the persistent symptoms in the back are as a result of the injury sustained at work and the underlying degenerative disease. I am of the opinion that the pre-existing degenerative disease is a component of the current impairment. I have deducted one-tenth as outlined under 10a applying the provision of s323(2) as a deduction is difficult or costly to determine."

1. The report of the MRI of the lumbar spine dated 12 July 2021 from Shoalhaven Medical Imaging, noted after "Clinical Details" the following: "Severe pain in lower back radiates to leg ? cause assess back". The comment at the end of the report is as follows: "Multilevel disc degeneration and bulge. L4/5 moderate canal stenosis and left L5 nerve root impingement. Multilevel facet arthrosis and hypertrophy."
2. Dr Bodel, in his report dated 24 August 2023, made no reference to any history of back pain and wrote: "There is no indication clinically of any pre-existing abnormality or condition which is contributing to this level of impairment, and therefore, there is no basis for a deduction for pre-existing impairment".
3. Dr Deshpande, in his report dated 28 February 2024, noted that the appellant suffers from "multilevel disc degeneration, local spinal stenosis in the lumbar spine". He noted that the appellant said that she had "no symptoms of back pain before March 2021".
4. In assessing WPI, Dr Deshpande wrote: "I also believe that she suffered from extensive pre -existing disc degeneration and stenosis. This will deduct 10% from the final WPI".
5. In a report dated 5 February 2022, Dr Ravi Kumar Cherukuri, treating neurosurgeon, noted that the appellant first noticed back pain in 1998 when she was "ear-ended" in a car accident and this worsened over the years including March 2021.
6. The clinical notes of Warrawong General Practice include the following entries:

(a) on 5 July 2021, Dr Romesh Sarvanandan noted: "Struggling with back pain, radiation to legs, wanting MRI to check";

(b) on 12 July 2021, Dr Romesh Sarvanandan noted "having MRI this afternoon of lower spine", and

(c) on 13 August 2021, Dr Romesh Sarvanandan noted "struggling with back pain and thinks is not able to work".

1. In the clinical notes of Illawarra Rehabilitation Clinic dated 17 February 2022, Nick Kontopoulos, exercise physiologist, noted that the appellant had a long history of back pain and "MVA some years ago then injured at work".
2. The appellant submits, firstly, that the Medical Assessor does not provide sufficient reasons to justify his one tenth deduction for the pre-existing condition in the lumbar spine. The Appeal Panel considers that the Medical Assessor provided adequate reasons for making a deduction of one tenth.
3. The Medical Assessor found that the appellant had evidence of underlying degenerative disease of the lumbar spine, an aggravation of pre-existing lumbar spondylosis, and a prior history of back injury which left her with intermittent back pain for some 20 years. The Medical Panel notes that the appellant consulted her general practitioner, several times in the six months before the injury at work on 3 December 2021 about back pain and had undergone an MRI scan to investigate the cause of that back pain. The Medical Assessor expressed the opinion that the persistent symptoms in the back were as a result of the injury sustained at work and the underlying degenerative disease. The Medical Assessor then expressed the opinion that the pre-existing degenerative disease was a component of the current impairment.
4. Secondly, the appellant submits that the Medical Assessor did not give reasons as to why it was "difficult or costly to apply a deduction". The Appeal Panel considers that the MAC needs to be read as a whole. The Medical Assessor found that the appellant had a pre-existing injury (motor vehicle accident) and condition (degenerative disease) in the back. The Medical Assessor was satisfied on the evidence that a proportion of the permanent impairment present after the injury was on 3 December 2021 was due to the earlier injury and the pre-existing condition.
5. The Medical Assessor then applied s 323(2) as he was of the opinion that it was too difficult or costly to apply a deduction. It is reasonable to infer from the MAC that the Medical Assessor believed that he did not have sufficient evidence, for example, medical records relating to the motor vehicle accident, on which he could make a different deduction.
6. The Appeal Panel was satisfied that the pre-existing condition contributed to the impairment assessed because of the extent of deterioration found in the investigations. The Appeal Panel also considered that a one tenth deduction was appropriate under s 323(2) as it was too difficult to determine the precise proportion that was caused by the pre-existing condition given the limited medical evidence in relation to the symptoms and complaints in relation to the lumbar spine before 2021. On balance, the Appeal Panel did not consider that a one tenth deduction was at odds with the evidence. This ground of appeal is not made out.

1. The appellant submits that the one tenth deduction under s 323 is not presumptive or default and only arises when properly reasoned deduction cannot be made because it would be "difficult or costly to determine" in the ordinary way. The appellant argues that no reasons are given as to why the one tenth discount applied as opposed to an actually reasoned out discount. The appellant submits that the Medical Assessor simply states that he proposes to apply s 323(2) with no reasons.
2. The Appeal Panel notes that the Medical Assessor does state that it was "difficult or costly to apply a deduction". Reading the MAC as a whole, the Appeal Panel considers that the Medical Assessor provided adequate reasons for the application of the one tenth deduction pursuant to s 323(2) of the 1998 Act.
3. As noted above, the Medical Assessor reported that the appellant suffered an aggravation of pre-existing lumbar spondylosis and there was evidence of underlying degenerative disease of the lumbar spine with a history of a back injury which left her with intermittent back pain. He considered that the persistent symptoms related to the work injury and the underlying degenerative disease and was of the opinion that the pre-existing degenerative disease is a component of the current impairment.
4. The Appeal Panel considers that it was open to the Medical Assessor to apply the one tenth deduction as that was the deduction he considered to be appropriate based on the clinical picture available to him and his own examination. The Appeal panel agrees with the respondent that as such, this is not a demonstrable error nor is the lack of reasons an error as the Guidelines set the circumstances in which this deduction is to be applied and is a well-known standard deduction.
5. Further, in Merza v Registrar of the Workers Compensation Commission [2006] NSWC 939, Hoeben J stated that a "demonstrable error" would essentially be an error where there is no information or material to support the finding made rather than a difference of opinion. In this matter, the Medical Assessor clearly diagnoses an aggravation of a pre-existing condition in the lumbar spine and applied a one tenth deduction, as per the Guidelines.
6. The Appeal panel agrees with the respondent that the Medical Assessor not addressing the specific issue of "difficult or costly to apply a deduction," does not form the basis for an appeal under s 327(3)(c) as this does not fall within the meaning of demonstrable error as noted in Merza.
7. In relation to scarring, the appellant submits that whilst the Medical Assessor briefly notes (at 10c) that Dr Bodel found pigmentation, the Medical Assessor simply says he found no pigmentation. The appellant argued that the existence or non-existence of pigmentation is a fairly significant difference and why pigmentation might be present one day and not the next has not been explained.
8. The Appeal Panel consider that the Medical Assessor stating that he found no pigmentation is an explanation in itself and no further explanation is required as it is merely a description of the scar's appearance.
9. Further, the Appeal Panel notes that it is obvious from the dates of the various assessments that this was not a situation where one doctor found pigmentation and the Medical Assessor found it was not present "the next" day. Dr Bodel's examination took place in August 2023, some 15 months after the appellant's surgery on 25 May 2022. The Medical Assessor examined the appellant on 5 February 2025, more than two and a half years after the surgery on 25 May 2022. It appears that there had been improvement in the scarring, as would be expected, and particularly the pigmentation since the examination by Dr Bodel in August 2023.
10. The Medical Assessor found no pigmentation on his examination. This was consistent with the comments made by Dr Deshpande in his report of 28 February 2024.
11. The appellant submits that while it is accepted that the Medical Assessor had to assess the appellant as he found her on the day, it was necessary to explain why his conclusions differed and not merely to state the existence of different opinions. The Appeal Panel does not accept this submission in respect to the finding of no pigmentation. The Medical Assessor had to provide his examination findings and then provide reasons for his assessment and comment on any difference with the other medical opinion, and this is what he did.
12. The Appeal Panel does not accept that the Medical Assessor failed to provide adequate reasons. This ground of appeal is not made out.
13. For these reasons, the Appeal Panel has determined that the MAC issued on