Todd v Ventia Australia Pty Ltd

DETERMINATION OF APPEAL PANEL
CITATION:	Todd v Ventia Australia Pty Ltd [2023] NSWPICMP 543
APPELLANT:	Margaret Todd
RESPONDENT:	Ventia Pty Limited
APPEAL PANEL
MEMBER:	Richard J Perrignon
MEDICAL ASSESSOR:	Mark Burns
MEDICAL ASSESSOR:	Drew Dixon
DATE OF DECISION:	1 November 2023
CATCHWORDS:	WORKERS COMPENSATION - Appeal from assessment of whole person impairment; whether examination for sensory loss in the median nerve was insufficient to support a negative finding; Held – Medical Assessment Certificate revoked and replaced.

BACKGROUND TO THE APPLICATION TO APPEAL

The appellant worker, Ms Todd, appeals from the Medical Assessment Certificate of Medical Assessor Kuru dated 3 April 2023.
On 13 February 2023, Ms Todd’s right upper extremity (wrist and hand) was referred for assessment of whole person impairment as a result of injury on 20 March 2019.
Reference was made in the referral to the Certificate of Determination dated
9 February 2023, which remitted the matter to the President for referral of the right upper extremity (hand, wrist) and TEMSKI. The latter is an acronym for the Table for the evaluation of minor skin impairment, which forms Table 14.1 of the Guidelines. For reasons that are not apparent to us, scarring was not referred for assessment.
Medical Assessor Kuru assessed a 1% whole person impairment (right upper extremity – wrist and hand) as a result of injury on 20 March 2019. He did so on the basis that he could find neither restricted range of motion on examination, nor sensory deficit.
The appellant submits that the Medical Assessor erred in failing to perform appropriate tests for sensory deficit in the median nerve distribution. She says that the Medical Assessor performed only the ‘light touch’ test, and failed to perform either the two-point discrimination test or the pinprick test. She asks that a member of the Appeal Panel examine her, and perform all relevant tests for sensory deficit.
No error is alleged in respect of the finding that there was no restriction in range of motion.
The Appeal Panel conducted a preliminary review of the Medical Assessment Certificate 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. They are not repeated in full, but are summarised briefly below.
The appellant submits as follows:
(a)    With respect to his assessment of the nervous system, the only reasons given by Medical Assessor Kuru for his assessment were there was 'No dermatomal sensory deficit to light touch’. He did not conduct any other testing.
(b)    AMA5 Chapter 16.3a directs an assessor to carry out clinical testing to examine the degree of functional loss of sensibility. Sensation to light touch alone cannot provide a conclusive assessment of sensory loss, and 'the presence of a normal light touch threshold does not necessarily indicate that two-point discrimination is normal in these cases': 16.5b, AMA5 at page 482.
(c)    Unlike the Medical Assessor:
(i)on 16 March 2022, Dr Assem who was qualified on behalf of the worker tested to light touch, pinprick and two-point discrimination, finding sensory deficit in the median nerve distribution;
(ii)Dr Lai tested with pinprick and two-point discrimination on 15 October 2019, finding sensory deficit, and
(iii)Dr McKessar, qualified by the insurer, reported on 30 April 2019 that there was ‘qualitative reduction in sensory appreciation in the right hand median nerve distribution and palmar territory’.
(d)    The failure to conduct two-point discrimination or pinprick testing in accordance with AMA5 amounted to demonstrable error and the application of incorrect criteria.
The respondent employer submits as follows:
(a)    The Medical Assessor ‘assessed her not to suffer from dermatomal sensory deficit on physical examination’.
(b)    Absent clear evidence to the contrary, ‘the regularity of the examination by the MA must be assumed’.
(c)    Though AMA5 says that two-point discrimination is the most widely used test, ‘AMA5 does not require a two point test to be followed’.
(d)    ‘It is also not apparent to the respondent (not being medically trained) that the examination performed by the Medical Assessor did not involve a test for two point discrimination’.
(e)    AMA5 provides that ‘only unequivocal and permanent sensory deficits are given permanent impairment ratings’. In this case, ‘the condition was not unequivocal’.
(f)    The Medical Assessor assessed the worker differently from Dr Assem, because she presented differently on the day of assessment: ‘The MA was required to carry out an assessment of the Appellant’s impairment, as she presented on the day. The MA may have regard to other medical opinions, but they are not bound by them …’.

Consideration

On 13 February 2023, Ms Todd’s right upper extremity (wrist and hand) was referred for assessment of whole person impairment as a result of injury on 20 March 2019.

Assessment of the upper extremity is governed by Chapter 2 of the Guidelines, which applies AMA5 Chapter 16 subject to modifications. AMA5 Tables 16-15, 16-10 and 16-11 are to be used to evaluate peripheral nerve lesions: Guidelines at [2.9]. Table 15 provides a range of upper extremity impairments from 3% to 39% in respect of nerves above and below the mid forearm.
At [5], Medical Assessor Kuru found as follows:
“There was no dermatomal sensory deficit to light touch.”
At [10b], he explained:
“I could not detect rateable impairment on the basis of restricted wrist range of motion or sensory deficit.”
At [10c], he explained the differences between his assessment and that of Dr Assem:
“With respect to the report by Dr Assem dated 16 March 2022, I did not find restricted range of motion, nor did I detect a sensory deficit and hence, have not assessed impairment for these.”
His reasons indicate that he tested for sensory deficit by using the ‘light touch’ method. There is no mention in the Medical Assessment Certificate of any other testing for sensory deficit. We are not satisfied that any other testing was used, including two-point discrimination or the pinprick test.
AMA5 Section 16.5 deals with impairment of the upper extremities due to peripheral nerve disorders. Section 16.5b provides:
“The methods for clinical assessment of sensibility are detailed in Section 16.3.”
Section 16.3a provides:
“All clinical tests used to examine the degree of functional loss of sensibility are related to cutaneous touch-pressure sensation. At present, the two-point test for fine discrimination sensibility is most widely used, followed by the monofilament touch-pressure threshold test. The pinprick test can be useful to determine whether pain protective sensation is intact and to identify discrepancies between dermatomal findings and reported symptoms. …
…
The static Weber two-point discrimination test is most valuable ...’
Section 16.3b provides:
“Only unequivocal and permanent sensory deficits are given permanent impairment ratings. Sensory impairment is rated according to the sensory quality and the distribution of the sensory loss.
The sensory quality is based on the results of the two-point discrimination test carried out on the distal palmar area of the digit …”
Section 16.5b provides:
“… In individuals with nerve lacerations, the presence of two-point discrimination usually indicates significant return of function. However, in conditions such as radiculitis, causalgia, and entrapment or compression neuropathy, normal two-point discrimination does not exclude the presence of abnormal light-touch/deep-pressure thresholds and anormal conduction studies. Conversely, the presence of a normal light-touch threshold does not necessarily indicate that two-point discrimination is normal in these cases. The use of the Semmes-Weinstein touch-pressure threshold monofilament test may be a helpful adjunct to the two-point discrimination test to help assess changes in light-touch sensibility.”
With respect to peripheral nerve impairment, the task of the Medical Assessor was to assess sensory loss of the right wrist and hand, by conducting a through physical examination and using his clinical expertise and judgment. The mere fact that there is no deficit to light touch did not compel a conclusion that there is no sensory deficit. A finding that there is no sensory deficit must be supported by all relevant tests. The light touch test, the two-point discrimination test, the monofilament touch-pressure threshold test and the pin prick test are all reasonably available and widely used. Of them, the ‘light touch’ test is by no means the most sensitive. As s 16.5b implies, circumstances may require a combination of these tests.
At the very least, the two-point discrimination test should have been deployed in this case before any reliable finding of ‘nil deficit’ could be made. So should Phalen’s Test and/or testing for Tinel’s Sign have occurred, both of which test for median nerve irritation (inflammation or compression), and are normally performed when examining for Carpal Tunnel Syndrome. In this case, reliance on the ‘light touch’ test alone is, in our view, insufficient to support a finding of no sensory deficit, because it did not exclude the possibility that the two-point discrimination test, Phalen’s test or testing for Tinel’s sign would reveal sensory deficit in the median nerve.
It follows that the examination was insufficient, either to assess whether there was sensory deficit, or to assess whether the deficit, if present, was ‘unequivocal and permanent’ in terms of Chapter 16.3b.
The reasons are insufficient to support the finding, demonstrating error, and requiring that the certificate be set aside.
We accept the respondent’s submission that the Medical Assessor was not obliged to accept or agree with the assessments of previous assessors, but that does not cure an insufficiency of examination or reasons.
As insufficient testing was conducted by the Medical Assessor to enable the Panel to make its own assessment, the Panel referred the worker to one of its members, Medical Assessor Dixon, for assessment of peripheral nerve impairment. His report follows.
“Report of Medical Assessor Dixon
1.   The workers medical history, where it differs from previous records
This 62 year old claimant had worked as a commercial cleaner at Kingswood TAFE for over 8 years and developed right carpal tunnel syndrome for which she had carpal tunnel decompression on 22 June 2020 by Dr Rohit Kumar at Nepean Private Hospital. Her recovery was uneventful except that she developed a ganglion at the volar aspect of her wrist next to her carpal tunnel surgical scar.
2.   Additional history since the original Medical Assessment Certificate was performed
Nil.
3.   Findings on clinical examination
There was altered sensation with a 4mm 2 point discrimination involving the thumb, index, middle and half the ring finger of her right hand, grade 4 out of 5, and there was weakness of thenar power, grade 4 out of 5 and wasting of the thenar muscle. Her Tinel’s sign over the median nerve was negative but the Phalen’s test was positive.
Her sensory impairment assessment is as follows:
That for her grade 4 out of 5 carpal tunnel syndrome on the right is from Table 16-15, Page 492, AMA V, 25% of 45%, giving 11% upper extremity impairment.
4.   Results of any additional investigations since the original Medical Assessment Certificate
Nil.”

Assessment

Having regard to his specialist expertise and clinical experience, the Panel accepts the clinical findings of Medical Assessor Dixon. Notwithstanding the negative Tinel’s sign, the combination of the positive Phalen’s test, the positive result on administering the two-point discrimination test, and Medical Assessor Dixon’s findings on weakness of thenar power and wasting of the thenar muscle together demonstrate that there was sensory deficit in the median nerve distribution. Having regard to the results, the Panel assesses an 11% upper extremity impairment (right wrist and hand).
When combined with the 2% upper extremity impairment assessed by Dr Kuru, this yields 13% upper extremity impairment, which equates to 8% whole person impairment (right upper extremity – wrist, hand).
The Medical Assessment Certificate of Medical Assessor Kuru is revoked and replaced with the attached Medical Assessment Certificate.

PERSONAL INJURY COMMISSION

APPEAL PANEL

MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

Matter number:	W8222/22
Applicant:	Margaret Todd
Respondent:	Ventia 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:

Table - whole person impairment (WPI)

Body Part or system

Date of Injury

Chapter,

page and paragraph number in WorkCover Guides

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

% WPI

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

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

Right upper extremity (wrist, hand)

20 March 2019

Chapter 2

459 16.18,

16.8a and 16.8b

460 16.9

438 16.1

439 16.2 and

16.3

nil

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

[2023] NSWPICMP 543

1 November 2023