Tony Esber and Australian Postal Corporation
[2013] AATA 419
[2013] AATA 419
Division GENERAL ADMINISTRATIVE DIVISION File Number
2012/2167
Re
Tony Esber
APPLICANT
And
Australian Postal Corporation
RESPONDENT
DECISION
Tribunal Ms N Bell, Senior Member
Dr I Alexander, MemberDate 21 June 2013 Place Sydney The Tribunal affirms the decision under review.
.........[sgd]...............................................................
Ms N Bell, Senior Member
CATCHWORDS
WORKERS COMPENSATION - compensation for injuries - notion of whole person impairment - obligation to pay compensation in the event of a 10% degree of impairment - use of American Medical Association's Guides to the Evaluation of Permanent Impairment - decision under review affirmed
LEGISLATION
Safety, Rehabilitation and Compensation Act 1988 (Cth), ss 24, 24(7), 27
CASES
Comcare v Broadhurst [2011] FCFCA 39
SECONDARY MATERIALS
American Medical Association’s Guides to the Evaluation of Permanent Impairment (5th ed)
REASONS FOR DECISION
Ms N Bell, Senior Member
Dr I Alexander, Member
21 June 2013
Tony Esber is employed by Australia Post as a truck driver. Mr Esber sustained an injury to his back in 2009 and Australia Post accepted liability for “acute lower back strain”.
Mr Esber claimed permanent impairment under sections 24 and 27 of the Safety, Rehabilitation and Compensation Act 1988.
It is uncontroversial that, in order to be paid compensation for permanent impairment, Mr Esber must have a percentage of Whole Person Impairment of 10% or more (s 24(7)). It is also agreed between the parties, and we concur, that, for the reasons stated by the Full Federal Court in Comcare v Broadhurst [2011] FCFCA 39, the appropriate Table on which to assess Mr Esber’s claimed impairment is Table 15.3 of the American Medical Association’s Guides to the Evaluation of Permanent Impairment (5th ed) (AMA 5).
ISSUES
The sole issue for us to consider is whether Mr Esber has a permanent impairment of 10% or more under Table 15.3 of AMA 5.
The text of the relevant columns and their relevant parts in Table 15.3 is as follows:
DRE Lumbar Category I
0% Impairment of the Whole Person
DRE Lumbar Category II
5-8% Impairment of the Whole Person
DRE Lumbar Category III
10-13% Impairment of the Whole Person
No significant clinical findings, no observed muscle guarding or spasm, no documentable neurologic impairment no documented alteration in structural integrity, and no other indication of impairment related to injury or illness; no fractures.
Clinical history and examination findings are compatible with a specific injury; findings may include significant muscle guarding or spasm observed at the time of the examination, asymmetric loss of range of motion, or nonverifiable radicular complaints, defined as complaints of radicular pain without objective findings; no alteration of the structural integrity and no significant radiculopathy.
Significant signs of radiculopathy, such as dermatomal pain and/or in a dermatomal distribution, sensory loss, loss of relevant reflex(es), loss of muscle strength of measured unilateral atrophy above or below the knee compared to measurements on the contralateral side at the same location; impairment may be verified by electrodiagnostic findings.
It is clear from the Table that, in order to obtain an assessment at the required level of 10% or more, Mr Esber must attract a rating under Category III.
Therefore the essential question for us to answer is whether Mr Esber attracts a rating under Category III of Table 15.3.
DOES MR ESBER HAVE AN IMPAIRMENT OF 10% OR MORE?
Table 15.3 of AMA 5, which is described in the heading to the part containing the Table as a diagnosis-related estimates method (DRE), is introduced by commentary in the nature of instructions to examiners. It also contains a number of definitions including the following that are relevant to Mr Esber’s presentation:
Radiculopathy
Significant alteration in the function of a nerve root or nerve roots and is usually caused by pressure on one or several nerve roots. The diagnosis requires a dermatomal distribution of pain, numbness, and/or paresthesias in a dermatomal distribution. A root tension sign is usually positive. The diagnosis of herniated disk must be substantiated by an appropriate finding on an imaging study. The presence of findings on an imaging study in and of itself does not make the diagnosis of radiculopathy. There must also be clinical evidence as described above.
Weakness and loss of sensation
To be valid, the sensory findings must be in a strict anatomic distribution, ie, follow dermatomal patterns. … Motor findings should also be consistent with the affected nerve structure(s). Significant, long-standing weakness is usually accompanied by atrophy.
Atrophy
Atrophy is measured with a tape measure at identical levels on both limbs. For reasons of reproducibility, the difference in circumference should be 2cm or greater in the thigh and 1cm or greater in the arm, forearm, or leg. The evaluator can address asymmetry due to extremity dominance in the report.
The instructions that appear in the relevant part include the following:
In most cases, using the definitions provided …, the physician can assign an individual to DRE category I, II or III. An individual in category I has only subjective findings. In category II, the individual has objective findings but no radiculopathy or alteration of structural integrity, while in category III, radiculopathy with objective verification must be present.
More general instructions are given to examiners under the heading ‘Principles of Assessment’ at page 374 and include the following:
History
The history should be based primarily on the individual’s own statements rather than on secondhand information. … It is not appropriate to question the individual’s integrity. If information from the individual is inconsistent with what is known about the medical condition, circumstances or written records, the physician should report and comment on the inconsistencies.
…
Examination
…
The physician should record and discuss any physical findings that are inconsistent with the history. Many physical findings are subjective, ie, potentially under the influence of the individual. It is important to appreciate this and not confuse such observations with truly objective findings.
…
More precise instructions are given, mainly in relation to straight leg raising, under the heading ‘Evaluation of Sciatic Nerve Tension Signs’.
Mr Esber told us that he injured his back in 2009 when he was exiting a truck and his knee gave way. He said he had pain initially in his lower back, down his buttocks and into both legs, but as time went by the pain became more severe in his left leg. He described his pain since then as being in his lower back, through his left buttock, in his left thigh, the outside of his left calf and then to his foot all the way to his toe. He said he has this pain all of the time and every ten minutes or so it becomes sharp and that sharpness lasts for about 30 seconds before it settles into its usual, less sharp level.
It is, of course, not for the Tribunal to perform the role of assessing medical expert. We must look to the expert medical evidence before us. Where, as here, we have a contest of assessments by medical experts, we must look to the extent to which each assessment has been informed by the relevant Table of assessment and the instructions for it.
In addition, there is the element of clinical judgment and experience of the medical expert. We must take this into account in any decision we make to prefer one assessment over another.
In this application, we are referred to two assessments by medical experts: first, the assessment of Dr Wallace, orthopaedic surgeon, of 11% under DRE Category III of Table 15.3 and, second, the assessment by Dr McGill, rheumatologist, of 8% under DRE Category II of Table 15.3.
The medical investigations background on which these experts’ opinions is to be considered is an MRI in November 2010 that showed L4/5 disc protrusion and nerve conduction and EMG studies in the same month that showed no neurogenic abnormality and no evidence of radiculopathy. Nevertheless, Dr Dowla, neurologist, who ordered the studies suspected a “mild L5 nerve root irritation”.
Dr Wallace reported on 29 November 2010 and 24 September 2012. In November 2010 he noted Mr Esber’s report of pain at the lumbar spine radiating to the paravertebral region, bilateral buttocks and posterior aspects of the lower limbs to the toes and feet bilaterally with intermittent paraesthesia and numbness at the posterior aspects of the lower limbs to the ankles bilaterally and weakness at his lower limbs and stiffness at his lumbar spine. He found on examination in November 2010 straight leg raising of 40 degrees on the right and 60 degrees on the left; calf circumference of 34 centimetres on the right and 35 centimetres on the left; equal and symmetrical reflexes; normal gait; decreased power of left great toe dorsiflexion; and decreased light touch sensation at the lateral aspect of the left calf.
In September 2012 Dr Wallace reported no pain radiating to the lower limbs. He noted intermittent paraesthesia on the lateral aspect of the left calf and the sole of the left foot. He recorded straight leg raising as 50 degrees on the right and 30 degrees on the left; equal and symmetrical reflexes; decreased power of the left great toe on dorsiflexion and decreased light touch sensation on the lateral aspect of the left calf and the sole of the left foot.
In oral evidence Dr Wallace agreed that straight leg raising can be feigned. However, he maintained that it was immaterial that, on examination by Dr Wallace in 2010 Mr Esber’s straight leg raising was worse on his right side, his good side, than on his left. When it was pointed out to him that Dr McGill had found straight leg raising normal on both sides and that Dr Dowla had found 80 degrees straight leg raising on both sides just 16 days after Dr Wallace’s examination, Dr Wallace said he had found no reason to conclude fabrication by Mr Esber. Dr Wallace said that if he had been concerned about fabrication he would have repeated the straight leg raising testing with Mr Esber in a seated, rather than supine, position. He said he did not do so on either examination.
Dr Wallace said that his finding that Mr Esber did not have classic L5 dermatomal distribution, in that his sensory loss included the sole of his foot, did not give him cause for concern either. He said that distribution would not exclude radiculopathy. He said he did not have Mr Esber close his eyes when testing for light touch sensory loss.
Dr Wallace also agreed that at a time of increased symptoms (which gave rise to a referral to Dr Dowla and a further MRI and electrodiagnostic studies) there would have been likely to be positive findings in the electrodiagnostic studies performed if radiculopathy was present. Dr Wallace also agreed that there is a difference between nerve root irritation, as suggested by Dr Dowla in the absence of positive electrodiagnostic findings, and radiculopathy. He agreed that Dr Dowla’s examination of Mr Esber, 16 days after his own examination, was normal in respect of all signs for radiculopathy.
Dr Wallace also said in answer to questions from the Tribunal that Mr Esber’s reported pattern of pain (pain at the lumbar spine radiating to the paravertebral region bilaterally to the left buttock with no radiation to his lower limbs with weakness of the left leg) was, in the absence pain behind the knee and sciatica, unusual. Dr Wallace also said that the pattern of pain Mr Esber described to the Tribunal (in his lower back through his left buttock, down his thigh, to the outside of his calf, down the top of his foot and into his big toe, constant but with a frequency of sharpness of 30 seconds every 10 minutes) was not the pattern of pain Mr Esber described to him in each of his consultations. He also said it would be unusual to have that frequency and severity of pain.
Dr McGill, rheumatologist, reported in December 2010 and February 2013. In 2010 he reported on examination that Mr Esber complained of pain in the lumbar region radiating to both buttocks with altered sensation of the lateral aspect of the left leg and small intermittent pains under the left foot with occasional pins and needles. He found normal gait, symmetrical lower limb muscle development, symmetrical and normal reflexes, full power in all muscle groups in the lower limbs – despite initial demonstration of give way weakness of dorsiflexion and plantar flexion of both great toes at different times before being asked to “try hard”; “subjective alteration” of sensation of the lateral aspect of the left leg and the whole of the left foot with normal sensation on the right. Dr McGill said this alteration of sensation involved both the L5 and S1 nerve root distributions. Straight leg raising was at 80 degrees bilaterally.
In February 2013 Dr McGill reported that Mr Esber complained of a pressure sensation in his low back which he likened to someone pushing on his back and fluctuating pain; pain in the low back, left buttock, left calf and toes after sitting for an extended period, but no pain in his thigh. He had a normal gait; symmetrical reflexes; full bilateral straight leg raising; and good symmetrical muscle development in the lower limbs. Dr McGill described the following in relation to testing for muscle power:
When tested on the right side he demonstrated excellent strength in all muscle groups in the right lower limb. When tested individually on the left side he demonstrated marked give way weakness of left great toe dorsiflexion, left great toe plantar flexion, left ankle dorsiflexion and left ankle plantar flexion. When great toe and ankle dorsiflexion were tested concurrently (left and right at the same time) he demonstrated give way weakness bilaterally.
Dr McGill considered this demonstrated a non-organic pattern of behaviour which, together with a pattern of sensory alteration that included the S1 and L5 nerve root distributions, indicated falsification. He found no radiculopathy.
In oral evidence Dr McGill explained the value of testing great toe and ankle dorsiflexion concurrently on both sides and the difficulty of feigning unilateral weakness. He considered it significant that on this concurrent testing Mr Esber showed weakness on the right side as well as the left even though when tested individually the right side had been strong. He concluded Mr Esber has no motor radiculopathy at L5.
Dr McGill said Mr Esber’s sensory assessment was not in keeping with L5 radiculopathy. He agreed there is a variability of dermatomal distribution but said there are some areas within those distributions that are very reliable, for example, the lateral border of the foot is almost invariably S1 and the medial border of the great toe is almost always L5. However, where the dermatomes overlap there can be variability. For that reason it is important to test in the middle of the dermatome. Dr McGill said he asks people to close their eyes when he tests for sensation.
Dr McGill also said that while a normal nerve conduction study might not necessarily exclude mild radiculopathy, a normal EMG would necessarily exclude radiculopathy causing weakness because an EMG is an electrical measure of motor function, although he conceded that these tests do not have perfect sensitivity. He agreed that evaluation in clinical practice and under the AMA 5 requires a holistic approach, with no one sign or test being sufficient to determine whether radiculopathy is present.
Dr McGill also confirmed that, in relation to the test for muscle power, Mr Esber was not trying. He also agreed that the test for sensory loss or abnormality is a very subjective test, dependent on a subject’s responses.
When the Tribunal recounted to Dr McGill the pattern and frequency of pain described by Mr Esber in his oral evidence, Dr McGill described it as an extraordinarily unusual pattern of symptoms and not one he had ever heard of before.
We have greater confidence in the clinical examination performed by Dr McGill than that performed by Dr Wallace. In particular, Dr McGill’s testing of muscle power, by testing both great toes and both ankles at once, allowed detection of cerebral drive as a cause of apparent weakness. We accept there was no motor radiculopathy at L5. The normal result on EMG confirms this for the reasons given by Dr McGill.
The area of sensory abnormality is a far less objective indicator, reliant as it is on responses of subjective feeling by the subject of the test. However, we are mindful of Dr McGill’s findings of a confused pattern of dermatomal distribution, involving both L5 and S1. Dr Wallace concluded a clear pattern of L5 distribution of sensory loss even though on his second examination he found sensory loss on the sole of Mr Esber’s foot, an area that does not feature in the L5 dermatomal.
In relation to straight leg raising, we are troubled by the unusual results obtained by Dr Wallace, especially so close in time to the normal results obtained by both Drs McGill and Dowla. The results obtained by Dr Wallace seem anomalous and we are not inclined to rely on them.
No medical expert found abnormal reflexes, unilateral atrophy or electrodiagnostic abnormalities.
The language used in AMA 5 is confusing in parts, particularly in relation to the possible distinction between “objective findings” in Category II and “significant signs” in Category III and the apparently variable objectivity of some measures and tests, acknowledged by the instructions themselves. Some light is cast by the instructions in AMA 5 that “in Category III, radiculopathy with objective verification must be present”. More light is cast by the definition of “weakness and loss of sensation” as requiring for valid findings of loss of sensation “a strict anatomic distribution, ie, follow dermatomal patterns” and that “(m)otor findings should also be consistent with the affected nerve structure(s). Significant, long-standing weakness is usually accompanied by atrophy”. Neither medical expert found such a loss of sensation and we prefer the findings of Dr McGill in relation to weakness.
We are not troubled by the research we were directed to on the variability of dermatomal patterns in individuals. Dr McGill readily agreed that such variations exist and explained that he allows for them in his testing by ensuring that he tests at the middle of the dermatome to avoid the variable as much as possible.
In addition, there is the ingredient of clinical judgment to consider. For the reasons we have given, we prefer the judgment of Dr McGill whose judgment appears to us to be based on a greater depth and rigour of analysis and a more effective testing practice.
For these reasons, we do not find that Mr Esber attracts a rating under DRE Lumbar Category III of Table 15.3. It follows that he does not have a Whole Person Impairment of 10% or more and an amount of compensation for permanent impairment is not payable to him.
DECISION
The Tribunal affirms the decision under review.
I certify that the preceding 39 (thirty -nine) paragraphs are a true copy of the reasons for the decision herein of Ms N Bell, Senior Member, Dr I Alexander, Member. ........[sgd]................................................................
Associate
Dated 21 June 2013
Date(s) of hearing 13 and 14 March 2013 Counsel for the Applicant L Grey Solicitors for the Applicant Carroll & O'Dea Lawyers Counsel for the Respondent M Gollan Solicitors for the Respondent Sparke Helmore
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