Leo v ABC Mesh Pty Ltd

DETERMINATION OF APPEAL PANEL
CITATION:	Leo v ABC Mesh Pty Ltd [2022] NSWPICMP 516
APPELLANT:	Matrix Leo
RESPONDENT:	ABC Mesh Pty Limited
Appeal Panel
MEMBER:	Richard Perrignon
MEDICAL ASSESSOR:	Tommasino Mastroianni
MEDICAL ASSESSOR:	James Bodel
DATE OF DECISION:	16 December 2022
CATCHWORDS:	wORKERS cOMPENSATION - Appeal from assessment of cervical spine; whether Medical Assessor erred in selecting diagnosis related estimate (DRE) category II; whether DRE category III appropriate as a result of surgery at two levels; whether surgery resulted from injury; Held – assessment set aside and replaced.

BACKGROUND TO THE APPLICATION TO APPEAL

The appellant worker, Mr Leo, appeals from the Medical Assessment Certificate of Medical Assessor Kuru dated 1 September 2022.
The Medical Assessor assessed a 16% whole person impairment (5% cervical spine; 6% right upper extremity – shoulder; 6% left upper extremity –shoulder) as a result of injury on 30 November 2017, when Mr Leo injured his neck and right shoulder at work. He later developed a condition of his left shoulder as a result of his injuries on that date.
Mr Leo alleges demonstrable error and the application of incorrect criteria in respect of the assessment of 5% whole person impairment (cervical spine) because, among other things, the assessor selected a DRE Cervical category II impairment on the basis that cervical spine surgery conducted by Dr Seex on 30 August 2018 did not result from injury. He notes that both Dr Doig and Dr Machart, on whose assessments the worker and the respondent had relied respectively, selected a DRE Cervical category III impairment, on the basis that the surgery resulted from injury.
No error is alleged in respect of the assessment of either shoulder.
The Appeal Panel conducted a preliminary review of the assessor’s medical assessment in the absence of the parties and in accordance with the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment (4th edition) (the Guidelines).

Submissions

The parties made written submissions which have been taken into account. It is unnecessary to repeat them in full. A brief summary follows.
The appellant submits as follows.
(a)    On 30 August 2018, neurosurgeon Dr Seex performed a C3-C7 decompression and laminectomy. The need for surgery resulted from injury. So much was conceded by the insurer when it paid for the costs of that surgery.
(b)    That surgery should have been taken into account in selecting the category of impairment using the DRE criteria. Taking it into account would have compelled the selection of a DRE category III impairment, as assessed by Dr Doig and Dr Machart.
(c)    The Medical Assessor found that here was no causal connection between the surgery and injury. As a result, a DRE category II impairment was selected.
(d)    His finding that there was no causal connection between surgery and injury relied on opinions expressed by Dr Seex to the effect that:
(i)the acute disc prolapse caused by injury had been ‘essentially re-absorbed’ (13 February 2018), and
(ii)the aim of the surgery was to increase the size of the congenitally narrow spinal canal to minimise chances of further problems (5 April 2018).
(e)    The Medical Assessor misconstrued the first of these opinions. Dr Seex merely said the prolapse had been partially absorbed.
(f)    The Medical Assessor also misconstrued the second opinion. Properly construed, Dr Seex was of the view that injury had materially contributed to the need for surgery.
(g)    Neither opinion supported the proposition that there was no causal nexus between surgery and injury.
(h)    In the alternative, the Medical Assessor gave too little weight to the opinions of Dr Seex, Dr Doig and Dr Machart, to the effect that the surgery resulted from injury.
(i)    The making of a 1/10^th deduction for a pre-existing congenital condition was in error, because the pre-existing congenital condition had already been taken into account by omitting to assess impairment resulting from surgery for that condition.
(j)    The making of such a deduction would not otherwise have been in error.
The respondent submits as follows in reply:
(a)    The Medical Assessor did not misconstrue the views expressed by Dr Seex.
(b)    He took them into account, but formed his own conclusions as to the nexus between injury and surgery.
(c)    He was both empowered and entitled to do so.
(d)    He is not bound by the opinions of other clinicians as to the nexus between injury and surgery.

Reasoning of the Medical Assessor

Medical Assessor Kuru took a history of injury on 30 November 2017, and of C3-C6 laminoplasty on 30 August 2018 at the hands of Dr Seex.
At [4], he noted the following explanation in Dr Seex’ letter to Allianz of 5 April 2018:
“[The proposed surgery] is to increase the size of the spinal canal and minimise chances of further problems. Given he has had one spinal cord injury from a disc prolapse with residual problems that may well be permanent, I think his capacity to withstand further injury is such that prophylactic surgery in this instance is reasonable. This is not a constitutional, degenerative condition or age-related change but is a congenital stenosis and he had a work-related disc prolapse.”
He offered the following diagnosis at [7] – emphasis added:
“… Mr Leo sustained a C3/4 disc protrusion with a cord contusion at the time of injury. The disc protrusion has essentially reabsorbed and Mr Leo has made significant neurological recovery with time.”
At [10b], he explained his reasons for selecting a DRE Cervical category II impairment – emphasis added:
“I understand Mr Leo has undergone a multiple level cervical decompression and according to SIRA Guidelines, page 29, paragraph 4.37 decompressive procedures should be assessed as DRE Cervical Category III with a further impairment assessed for multiple levels of surgery. As noted above, the Treating Surgeon has indicated that the role for decompression was due to underlying congenital stenosis and was a prophylactic procedure rather than being surgery related to the work-related injury. This being the case and assessing the work-related injury, I assess Mr Leo according to AMA-5, page 392, Table 15-5 as DRE Cervical Category II on the basis of his injury with non-verifiable radicular complaints.”
At [10c], he referred to Dr Doig’s selection of a DRE Cervical category III impairment, and explained:
“This assessment has been made on the basis of the decompression being undertaken to treat an injury which was not the case.”
He notes that Dr Machart had assessed DRE category III on the same basis.
At [11] he indicated a deduction of 1/10^th for pre-existing ‘cervical spine congenital stenosis and degenerative spondylosis’.

Consideration

AMA 5 Table 15-5 sets out the criteria for assessing impairment of the cervical spine. Paragraph 4.37 of the Guidelines provides that, notwithstanding those criteria, surgical decompression for spinal stenosis merits DRE category III.
On 30 August 2018, Mr Leo came to surgical decompression for spinal stenosis at C3-C6.
Unlike Dr Doig and Dr Machart, Dr Kuru declined to assess DRE Cervical category III, on the basis that there was no causal connection between injury to the cervical spine and surgery.
The appellant alleges that Dr Kuru erred in finding there was no causal nexus between injury and surgery. As his reasons make plain, Dr Kuru did make that finding. He had power to make it, because it was his task to assess the level of permanent impairment, and to determine whether all or any part of the impairment resulted from injury. That includes a finding as to whether all or any of it resulted from surgery which itself resulted from injury.
The first issue is whether it was reasonably open to the Medical Assessor to find that there was no causal nexus between injury and surgery on 30 August 2018.
Dr Kuru reasoned:
(a) that the disc prolapse caused by injury had been ‘essentially reabsorbed’ prior to surgery, and
(b) that surgery was necessary to address a pre-existing canal stenosis rather than the effects of injury.
He did not explain why he reached the first conclusion. He did not suggest that either the history taken, the results of clinical examination or radiological studies formed a basis for it. In the circumstances, it is a reasonable inference that he relied on the opinion expressed by Dr Maharajan and Dr Seex in their report dated 13 February 2018, concerning their examination of the patient that day, which was before the Medical Assessor :
“We told him [Mr Leo] that he could have developed an acute disc prolapse which has partially resorbed.”
The authors concluded their report by indicating their intention to ‘discuss the [existing] MRI with our colleagues on Thursday morning and we will review him again after the x-ray and discuss further management plans including surgery …’.
That passage indicates that what they told Mr Leo represented a hypothesis subject to further discussion, investigation and review. Neither its terms nor its context suggests that it represented a concluded view.
On 5 April 2018, Dr Seex provided the following further explanation to Allianz, of which only part is reproduced in the Medical Assessment Certificate – emphasis added:
“I think he had a cervical disc prolapse which, given a degree of congenital cord narrowing, has resulted in damage to his spinal cord. The mechanism of injury is consistent with this diagnosis and the MRI has shown a cord contusion around the level of the disc consistent with this so I believe the whole picture is consistent here. The Tl sequence was suggestive of residual posterolateral disc herniation at C3/4.
I think he has clearly suffered a spinal cord injury as a result of this and the acute event likely to have been a disc prolapse but there is a congenital predisposition because of his canal stenosis and it's the rationale for laminoplasty, which is like a laminectomy, hopefully minimising the chances of kyphotic deformity. This is to increase the size of the spinal canal and minimise chances of further problems. Given he has had one spinal cord injury from a disc prolapse with residual problems that may well be permanent I think his capacity to withstand further injury is such that prophylactic surgery in this instance is reasonable. This is not constitutional degenerative condition or age related changes as [sic, so much as] a congenital stenosis and he had a work related disc prolapse. I think his work did contribute to this injury.
I am less concerned about the C3/4 disc, which has partially resolved, I suspect he will have some degree of ongoing problems.”
We interpret Dr Seex to mean that the worker suffered a disc herniation at C3/4, which in turn impacted upon and injured the spinal cord, that the presence of pre-existing canal stenosis at that level rendered the worker more susceptible to this kind of injury than he otherwise would have been, and that decompression was needed to address an ongoing vulnerability of the spinal cord to such contusions from an already injured - and therefore weakened - disc.
By indicating that the condition of the disc had only ‘partially resolved’, Dr Seex made it plain that he considered there was residual disc pathology, consistent with the results of the TI sequence to which he referred. The danger to the spinal cord, therefore, emanated from the combination of canal stenosis and a weakened and injured disc with residual pathology.
It follows that, in Dr Seex’ view, there was a causal connection between injury to the disc, and the ongoing risk of further injury to the spinal cord. It was this risk that the surgery was designed to address. It also follows that Dr Seex considered there was a common sense chain of causation between injury and the need for surgery. He would not otherwise have requested to the insurer to approve the surgery and pay for it, as he did.
Dr Kuru appears to have misconstrued Dr Seex to mean that there was no causal nexus between injury and the need for surgery. In our view, his understanding of Dr Seex’ report was in error.
He gave no other reasons for making the finding that he did. In our view, the finding he made was not reasonably open to him, either on a fair reading of Dr Seex’ opinions, or on the basis of any other evidence before the Medical Assessor.
It does not matter whether the disc material had been partially resorbed, as Dr Seex seems to have thought, or ‘essentially reabsorbed’ as Dr Kuru put it. The purpose of the surgery was to address the risk of injury to the spinal cord from further disc herniations, in circumstances where the disc was affected by residual pathology resulting from injury.
The finding that surgery did not result from injury was essential to the assessment of a DRE Cervical category II impairment. That finding was not reasonably open on the evidence. It demonstrates error on the face of the certificate, requiring that the certificate be set aside and replaced by a Medical Assessment Certificate assessing a category DRE III impairment.
It is unnecessary to consider whether the deduction of 1/10^th was in error, as the appellant does not submit that it would be, in circumstances where a DRE category III impairment is assessed.
The range of impairment permitted within DRE II is 5% to 8%. From this range, Dr Kuru selected the lower amount of 5%. No error was alleged in respect of this selection, save that the assessment should have been DRE III. In accordance with the Medical Assessor’s clinical findings, in the allowable range of 15% to 18% for DRE III, we select 15%, and add 1% for the effects of daily living (as did the Medical Assessor, Dr Machart and Dr Doig) and 2% for surgery at two levels, yielding 18%. After deducting 1/10^th for a pre-existing condition (as did the Medical Assessor), and rounding to the nearest integer, whole person impairment in respect of the cervical spine is 16%.

Conclusion

For the reasons given, the Medical Assessment Certificate dated 1 September 2022 is revoked and replaced by the attached Medical Assessment Certificate.

APPEAL PANEL

MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

Matter Number:	W3362/22
Applicant:	Matrix Leo
Respondent:	ABC Mesh Pty Limited

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act1998.

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

Body Part or system	Date of Injury	Chapter, page and paragraph number in NSW workers compensation guidelines	Chapter, page, paragraph, figure and table numbers in AMA5 Guides	% WPI	WPI deductions pursuant to S323 for pre- existing injury, condition or abnormality (expressed as a fraction)	Sub- total/s % WPI (after any deductions in column 6)
Cervical spine	30/11/17	Page 28 Para 4.34 Page 29 Para 4.37	Page 392 Table 15-5	18	1/10	16
Right upper extremity (shoulder)		Page 476 Fig 16-40 Page 477 Fig 16-43 Page 479 Fig 16-46 Page 439 Table 16-3	7	1/10	6
Left upper extremity (shoulder)			7	1/10	6
Total % WPI (the Combined Table values of all sub-totals)					26

[2022] NSWPICMP 516

16 December 2022