Huynh and Australian Postal Corporation

[2008] AATA 179

Administrative Appeals Tribunal

DECISION AND REASONS FOR DECISION [2008] AATA 179

ADMINISTRATIVE APPEALS TRIBUNAL        )	No	N 200600263
)	2007/1767
GENERAL ADMINISTRATIVE DIVISION          )
Re	THUY NGOC HUYNH

Applicant

And AUSTRALIAN POSTAL CORPORATION

Respondent

DECISION

Tribunal Ms N Bell, Senior Member
Dr M Thorpe, Member

Date3 March 2008

PlaceSydney

Decision The decisions under review are affirmed.

[sgd] Ms N Bell

Senior Member

COMPENSATION – Bilateral Cervical Brachial Syndrome – Bilateral Carpal Tunnel Syndrome – Whether cervical brachial syndrome caused by nature and conditions of work – Whether carpal tunnel syndrome caused, or aggravated by work incident – Decision under Review is Affirmed

Safety, Rehabilitation and Compensation Act 1988

REASONS FOR DECISION

Ms N Bell, Senior Member
Dr M Thorpe, Member        

1.      Mrs Huynh, who has worked for Australia Post for some 16 years, complains of two physical conditions. The first affects her neck, shoulders and upper arms. When she lodged a claim for this condition in relation to the nature and conditions of her work, it was characterised as bilateral cervical brachial syndrome. Liability was denied and that denial was affirmed on 26 April 2007.

2.      The second condition complained of by Mrs Huynh is bilateral carpal tunnel syndrome. She claimed for this condition on 26 August 2005. Comcare affirmed its denial of liability on 25 January 2006.

3.      The parties agree, and we concur, that the two conditions, whatever their cause, are separate. Our reasons for that conclusion follow.

4.      Mrs Huynh contends that her cervical brachial syndrome is the result of her work as a mail officer over the period from 1990 to 2005, with specific incidents in 1996 and 2005. She also contends that her carpel tunnel syndrome arose following an incident in August 2005 when she lifted a heavy parcel. Mrs Huynh had surgery for her carpal tunnel syndrome in 2006 and she is now back to full-time work. She claims a period of incapacity for work of approximately 17 months.

issues

5.      The issues we must consider are whether Mrs Huynh’s cervical brachial syndrome was caused by the nature and conditions of her work and whether her carpal tunnel syndrome was caused, or aggravated, by the incident at work in August 2005.

6.      We consider the two conditions to be separate in their symptomatology and aetiology.   

7.      Dr Berry, General Surgeon, is the only medical practitioner who linked the two conditions together. He considered that the symptoms in the upper limb were not those of carpal tunnel syndrome, but due to an overuse syndrome. He then referred to a “secondary carpal syndrome” as part of the overuse syndrome secondary to the types of work she was doing. He relied on the fact that pain from carpal tunnel syndrome does not extend above the wrist, an opinion with which both Dr McGill and Professor Sambrook, Rheumatologists, disagreed. Dr McGill’s evidence was that pain from carpal tunnel syndrome can go up as far as the shoulder but not the neck. Professor Sambrook, by referring to the American Medical Association Guide No. 5, said that pain from carpal tunnel syndrome can extend beyond the wrist and involve the elbow and shoulder. Professor Sambrook did not accept the possibility of an overuse syndrome resulting in a secondary carpal tunnel syndrome. Dr McGill considered the concept of occupational overuse syndrome or Repetitive Strain Injury to be invalid. Dr Berry himself acknowledged that the diagnosis of overuse syndrome was not accepted by most of his colleagues. We accept Professor Sambrook’s and Dr McGill’s opinions that a secondary carpal tunnel syndrome cannot be part of an overuse syndrome and that the two conditions cannot be merged into one.

8.      We heard and read evidence from Professors Sambrook and Connolly and Drs McGill and Berry and others on the question of the cause of each condition. Their evidence was divergent and, in some respects, irreconcilable. All went to the customary underlying causes of the conditions and to the probable underlying causes for Mrs Huynh, in particular.

cervical brachial syndrome

9.      Mrs Huynh’s neck, shoulder and arm problems date back to 1996 when she experienced pain when pulling a heavy bag of parcels at work. An MRI showed a C5/6 disc lesion, according to both Dr McGill and Dr Guirgis, Orthopaedic Surgeon. Dr McGill considered she had cervical spondylosis not related to her work and Dr Guirgis attributed the disc lesion to stress at work. In May 1999, Mrs Huynh consulted Dr White, Rheumatologist, complaining of discomfort in her neck. He noted mild degenerative changes at C5/C6. He considered her to have mild cervical spondylosis with symptoms that bother her from time to time but that would not be aggravated by her work or be complicated by progressive functional impairment.

10.     Mrs Huynh complained of pain running down her left arm from the shoulders, following an incident on 17 August 2001. She was seen by Dr McGroder, Occupational Physician, on 17 September 2001 who could find nothing objective on which to base Mrs Huynh’s symptoms of right neck, shoulder and arm pain. He noted an EMG suggestive of Carpal Tunnel Syndrome but regarded this as a false positive as she had similar electrophysiological findings on the right without symptoms. He thought that it was most likely she had suffered a muscle strain.

11. She was denied compensation in 2001 for her neck and arm symptoms, but on review liability was accepted for bilateral carpal tunnel syndrome under s14 of the Safety, Rehabilitation and Compensation Act 1988.

12.     In May 2002, Dr Chase, Occupational Physician, obtained a history of pain in the left shoulder and upper arm following the incident on 17 August 2001. The Claim for Compensation report of that incident describes the type of pain or injury as “pain running down the left arm from the shoulder, when sorting mail and printing labels”. Dr Chase made no definitive diagnosis other than mild carpal tunnel syndrome without any work restrictions.

13.     On 11 July 2002, Dr Boker, Orthopaedic Surgeon, obtained a history of left neck and shoulder pain beginning about August 2001, when Mrs Huynh was putting labels through a printer in a repetitive fashion. He noted an earlier history of neck problems in 1997, at which time an MRI showed a mild C5/C6 disc lesion. He considered her complaints to be cervico-brachial in nature. Examination of the cervical spine and shoulder revealed a full range of movement with mild tenderness over the cervical spine and left trapezius consistent with mild degenerative change.

14.     Professor Sambrook on 28 August 2006 obtained a history of pain on the left side of the neck and left arm since 1996 and that these symptoms had been intermittent until August 2005. The symptoms had become different in 2001 when she developed pain and numbness in the left hand. Concerning diagnosis, he considered that cervical disc disease probably explained her initial left upper arm and cervical symptoms in 1996 and may explain her current upper limb symptoms. He considered the cervical spondylosis to be constitutional in origin.

15.     Dr McGill originally saw Mrs Huynh on 20 March 1997. The history he obtained was that while opening parcels in about June 1996 she felt discomfort in the neck and shoulders with continuing intermittent discomfort in the neck and shoulders. He diagnosed cervical spondylosis at the C5/6 level with a mild posterior protrusion and the symptoms reported were consistent with cervical spondylosis. Dr Guirgis had first seen Mrs Huynh on 26 November 1996, obtaining a history of stressful activities with her neck and an arm on 12 June 1996. He described the stressful activities as consistent with post traumatic mechanical derangement of the neck caused by musculo-ligamentous strain/strain with implication of C5/6 intervertebral disc. He was in agreement with Dr McGill concerning the C5/6 disc lesion. Dr Guirgis attributed the C5/6 lesion to work whilst Dr McGill considered it to be constitutional.

16.     When Dr McGill saw Mrs Huynh seven years later on 18 October 2006, he considered that as she continued to have symptoms maximal in the left upper arm following successful carpal tunnel release, this was a reflection that most of her upper arm symptoms had not been due to a carpal tunnel. He considered the underlying cause of her current symptoms was cervical spondylosis. He considered her cervical spondylosis was constitutional in origin and he did not think her work activities had any potential to cause a more prolonged change in the level of symptoms experienced as a result of the cervical spondylosis nor to produce any change in the pathology. He recommended she avoid heavy lifting.

17.     Both Dr McGill and Professor Sambrook consider Mrs Huynh’s cervical spondylosis to be constitutional in origin and not work-related. On balance we consider the cervical spondylosis to be the cause of her shoulder and arm symptoms dating back to 1996. The cervical spondylosis is constitutional in origin and not arising from the nature and conditions of employment.

18.     It follows that there is no liability to pay compensation in respect of this condition.

carpal tunnel syndrome

19.     Mrs Huynh has suffered from bilateral carpal tunnel based on her clinical symptoms and EMG studies, since at least 2001. There was one mention of carpal tunnel syndrome in her clinical notes in 1996 by a local practitioner, but none further until 2001. We note that Dr McGill said she "probably" suffered from carpal tunnel syndrome, which was surprising. In part this may reflect Dr McGill’s opinion that there be a non-organic nature of behaviour during physical examination. She has had electrophysiological studies confirming the diagnosis and she came to surgery by Dr Yee, Hand Surgeon, in March 2006, to relieve the left carpal tunnel syndrome. Subsequent to surgery her left carpal tunnel was effectively cured, with a normal EMG. The right carpal tunnel has remained essentially asymptomatic despite EMG findings similar to the left.

20.     We realise that there has been difficulty separating the symptoms from the neck and arm and the symptoms from the carpal tunnels. In particular, the Delegates have had difficulty separating the two and not unreasonably have included carpal tunnel in the neck and upper arm assessment.

21.     This claim emanated from an incident at work on 19 August 2005 when Mrs Huynh described an exacerbation of pain and numbness in her hands which her local doctor Dr Clayton, referred to as bilateral cervico-brachial syndrome and bilateral carpal tunnel syndrome.

22.     Differing opinions were provided by the specialists concerning the contribution of her work toward the carpal tunnel syndrome. We do not accept the opinion of Dr Berry for the reasons previously outlined. Dr Chase quoted an article on the Mayo Clinic Web site denying any relationship between repetition, lifting and carpal tunnel syndrome. Professor Sambrook also referred to the same Mayo Clinic Web site which said:

"Although it is not clear which activities can cause carpal tunnel syndrome, if your work or hobbies are hand intensive – involving a combination of awkward, repetitive wrist movements or finger motions, forceful pinching or gripping or working with vibration tools – you may be at a higher risk of developing the condition.”

23.     Professor Sambrook is of the view, based on the articles by Moustafa and Stapleton and in part endorsed by the Mayo Clinic, that repetition and force are significant risk causation factors for carpal tunnel syndrome and apply to Mrs Huynh.

24.     Dr Stapleton was quite forthright that force and repetition had no role to play in the genesis of carpal tunnel syndrome and stated in his December 2007 report:

“There is no evidence that repetitive activities aggravate the pathology of carpal tunnel syndrome. Professor Sambrook disagreed and considered Dr Stapleton drew a distinction between symptoms and pathology.”

25.     Professor Sambrook said that if a patient is experiencing chronic symptoms and continues to perform the same activities long term, it is reasonable to have long term consequences. The mechanism by which this may occur is either by tenosynovitis or chronic ischaemia. He also referred to Professor Connolly's report of 20 October 2005 which refers, at page 3, “An increase in flexor synovial content as being a factor which could aggravate the problem”.

26.     Professor Connolly had considered Mrs Huynh's carpal tunnel mostly arose from a constitutional condition but some work duties, such as lifting, loading and twisting of the wrist can be an aggravating factor. He stated “her employment and the injury could be regarded perhaps as a 10% aggravating factor", an opinion he changed when he obtained an earlier four year history of carpal tunnel. He did not elaborate on the reason for his change of opinion.

27.     Professor Sambrook referred to each of the tendons traversing the carpal tunnel as having a thin lining, called tenosynovium. He said that if they become thickened or if there is inflammation and fluid enters into the canal, an increase in pressure results. Alternatively, the increase in pressure could be due to ischaemia of the nerve which may or may not be related to the alterations to the synovium.

28.     Professor Sambrook said that carpal tunnel syndrome can become chronic and irreversible and if patients have such severe carpal tunnel they get wasting of muscles in the thumb. Even if the carpal tunnel is reversed that wasting may never go away.

29.     Dr McGill reported:

“I think the published studies support the conclusion forceful repetitive duties will increase the likelihood of a person experiencing carpal tunnel syndrome. Light repetitive duties such as keyboard work do not increase the likelihood of someone experiencing carpal tunnel syndrome. The duties she performed were repetitive and would have involved a moderate amount of wrist movement.”

Dr McGill’s opinion was that because Mrs Huynh’s symptoms did not improve and in fact worsened when the aggravating work related features were removed from her environment (ie when she was on restricted duties for only four hours a day), and that indicates her problems were constitutional and not related to work. We note Mrs Huynh’s oral evidence confirming this worsening.

30.     Dr McGill further reported that:

“If the activities are forceful enough and repetitive enough that you may not only get an increase in symptoms at the time of doing those activities but you can also have a permanent effect causing ongoing symptoms.”

31.     The issue for the Tribunal was narrowed to one of whether, if the aggravating factors were removed and the symptoms persist or worsen, this indicates that the condition is constitutional rather than work related. Professor Sambrook considered this to be a matter of degree. If the condition was entirely work related the symptoms would go away and if the changes had not become chronic one would expect some improvement. If it was partly work and partly constitutional, it would be hard to know and depend on how long the insult, whether it be constitutional or work-related, had been compressing the nerve and whether the changes had become chronic. This is because if the changes had become chronic in the nerve, then any inciting activity may not allow improvement in the symptoms. Also, the longer the history, the more likely it is to be chronic.

32.     Dr McGill relied on the history given by Mrs Huynh that the symptoms of carpal tunnel became worse after she was placed on restricted light duties. He maintained that if the work activities were responsible for the symptoms of carpal tunnel syndrome one certainly would not expect them to deteriorate during the period when the activities were being restricted. Dr McGill agreed that forceful repetitive activities can cause a thickening of the tenosynovial membrane. But if the person reduces those activities, the synovial membrane gets thinner and goes back to normal. In examination in chief he said:

"It can happen with force or repetitive activities and it steadily and quickly improves when these activities are reduced. It did not make sense for symptoms of carpal tunnel syndrome to actually progressively increase during a period of reduced activity".

33.     Professor Sambrook and Dr McGill elicited different clinical findings subsequent to surgery. Professor Sambrook described diminution of pinprick in the left hand principally in the distribution of the median nerve but no alteration in two point discrimination. By contrast, Dr McGill's testing had Mrs Huynh reporting a variable pattern of subjective sensory alteration, clearly inconsistent with median nerve dysfunction. These examinations were subsequent to a normal EMG 12 June 2006.

34.     As a matter of logic, it is difficult to escape the conclusion that Mrs Huynh’s increased carpal tunnel symptoms were not due to her work. The fact relied on by Dr McGill, that her symptoms became worse after her work was lightened, is persuasive. The theories offered by Professor Sambrook, of chronicity due to ischaemia or permanent thickening of the tenosynovium, remain theories and there is no evidence to suggest that these phenomena occurred in relation to Mrs Huynh.  Any chronicity of carpal tunnel syndrome appears to be unaffected by Mrs Huynh’s work activities.

decision

35.     The decisions under review are affirmed.

I certify that the 35 preceding paragraphs are a true copy of the reasons for the decision herein of Ms N Bell, Senior Member and Dr M Thorpe, Member.

Signed:   
  [sgd]
  Mark Dowsett
  Associate

Dates of Hearing  22 August 2007, 12 December 2007 and 13 December 2007 

Date of Decision  3 March 2008

Counsel for the Applicant         Mr Leo Gray
Solicitor for the Applicant          Michael Coorey, C & M Lawyers

Counsel for the Respondent     Mr Geoffrey Johnson 
Solicitor for the Respondent     Graham Jones, Graham Jones Lawyers