Decision #183/99 - Type: Workers Compensation


An Appeal Panel hearing was held on August 30, 1999, at the request of a union representative, acting on behalf of the claimant. The Panel discussed this appeal on August 30, 1999.


Whether or not the claim for carpal tunnel syndrome is acceptable.


That the claim is not acceptable.


In May 1997, the claimant filed a workers compensation claim for left and right wrist problems which he related to his occupation as a bus driver. On August 29, 1997, an orthopaedic specialist diagnosed left wrist carpal tunnel syndrome (CTS) and recommended a carpal tunnel release. On September 12, 1997, the employer’s representative opposed the acceptance of the claim stating that the wrist activities involved in the operation of a transit bus would not cause CTS.

During a telephone conversation with the claimant on December 17, 1998, an adjudicator with the Workers Compensation Board (WCB) documented the following information:

  • the claimant felt his CTS was caused from the repetitive motion of driving a transit bus and turning the steering wheel. The symptoms were only in his left hand to start but over the last couple months he started to get symptoms in his right hand.The claimant indicated that he uses both hands equally while driving the bus and could not say that he used one hand more than the other while driving.
  • all buses have power steering and have had this for at least 12 years.The claimant did not feel the steering wheels are strenuous to turn but advised that some are stiffer than others.The steering is not as easy as a car.  
  • prior to starting with transit the claimant worked as a driver instructor and prior to that he worked for a company delivering produce.The claimant stated he had absolutely no hand conditions prior to June 1997.  
  • the claimant described driving activities as using the push/pull method. He operated a door lever with his left hand and hands out transfers with his right hand.The claimant could not think why his left hand would be worse than the right but advised that since it was his non dominant hand it may be weaker and more susceptible to injury.
  • the claimant described himself as 5’9” and weighed 245-247 pounds.He was diagnosed with a thyroid condition about 4-5 years ago.  X-rays of his hands were apparently normal.

Following consultation with a WCB medical advisor on December 18, 1997, primary adjudication wrote to the claimant on January 7, 1998. The claimant was advised that no further consideration would be given towards his claim until the results of nerve conduction studies were received.

On February 10, 1998, nerve conduction studies confirmed the presence of moderate left and mild right CTS. On March 18, 1998, a WCB medical advisor noted the results of the nerve conduction studies and stated that the claimant’s job duties could have caused the condition. The medical advisor also commented that the claimant had some arthritis, which may be contributing to his condition. As there was no external causes identified, the medical advisor was prepared to authorize surgery on the left side if the adjudicator was in favour of the claim.

Subsequent file documentation contained a report from the family physician dated June 3, 1998, which included a report from a physician specializing in occupational and environmental medicine dated April 16, 1998. The attending physician commented that the specialist confirmed that the claimant had bilateral CTS, which was worse on the left than on right. The specialist went on to state that in her opinion the claimant's duties as a bus driver may have played a partial, if not a major role in the development of his CTS. She did not feel that the claimant's well controlled hypothyroidism had any effect on the development of CTS. The specialist also suggested a second opinion regarding the need for surgery.

On June 8, 1998, physicians from the Hand Clinic indicated bilateral CTS had been established but that the claimant’s symptoms and physical findings were more acute on the left side. The claimant was placed on a waiting list for exploration.

In a report dated October 14, 1998, the hand specialist outlined his findings with regard to the left median nerve exploration that was performed on September 15, 1998 not received by the WCB until the end of November 1998.

On November 23, 1998, the claimant was advised that his claim for bilateral CTS was accepted and that left CTS decompression surgery was authorized. On March 8, 1999, the employer appealed the decision to Review Office.

In a decision dated April 9, 1999, Review Office determined that the claim for CTS was not acceptable. Review Office pointed out that from the available medical literature, CTS can be both work related as well as non-work related. It did not believe that the job tasks of a transit bus driver constituted continuous, repetitive tasks that would lead to the development of CTS. Review Office believed the hand activities of a bus driver are variable with the use of the hands for driving as well as for opening the door, providing transfers, pushing the fare box lever as well as pushing switches on a periodic basis. In the opinion of Review Office, these activities were variable and periodic in nature and are not performed on a sustained basis over a prolonged period of time. Review Office did not believe the occupation of a bus driver was a causal factor in the development of CTS.  The Review Office’s decision was appealed by the claimant’s union representative on March 23, 1999, and an oral hearing was arranged and held on August 30, 1999.

Following the August 30, 1999, hearing, the claimant's union representative was given the opportunity to submit a response with respect to the new and additional evidence that was provided by the employer's representative at the hearing. Responses were received from both the union and employer's representatives dated September 8, 1999, September 22, 1999, and October 4, 1999.

On October 7, 1999, the Panel met again to discuss the case with respect to the union and employer representative’s submissions along with the new and additional information that was submitted at the hearing. Consequently, the Panel requested that the case be referred to a medical advisor at the WCB for a further opinion with regard to the October 14, 1998, report from the treating hand specialist. A response from the medical advisor dated November 2, 1999, was forwarded to the interested parties for comment.

In the interim, the union representative requested that the Appeal Panel postpone its upcoming meeting as he was consulting with the treating hand specialist for an opinion with respect to the operative findings outlined in his report dated October 14, 1998.

Subsequently,the Panel received the union representative’s submission dated November 24, 1999, which included a copy of the hand specialist’s report dated November 22, 1999. This was then forwarded to the employer’s representative for rebuttal argument, which was later received on November 26, 1999. On December 14, 1999, the Panel met to render its decision, which took into consideration a final submission from the union representative dated December 2, 1999.


The issue in this appeal is whether or not the claim for bilateral carpal tunnel syndrome is acceptable. The relevant subsections of The Workers Compensation Act (the Act) are subsections 1(1) which defines accident and subsection 4(1) which provides for the payment of wage loss benefits to a worker where the worker sustains personal injury by accident arising out of and in the course of employment.

In accordance with the Act it must be established initially that the worker sustained an accident within the meaning of subsection 1(1).

Subsection 1(1) states:


1(1) In this Act,

“accident” means a chance event occasioned by a physical or natural cause; and includes

(a) a wilful and intentional act that is not the act of the worker

(b) any

(i) event arising out of, and in the course of, employment, or

(ii) thing that is done and the doing of which arises out of, and in the course of, employment, and

(c) an occupational disease

and as a result of which a worker is injured:

Subsection 4(1) states:

Compensation payable out of accident fund

4(1) Where, in any industry within the scope of this Part, personal injury by accident arising out of and in the course of the employment is caused to a worker , compensation as provided by this Part shall be paid by the board out of the accident fund, subject to the following subsections.

The worker has been diagnosed as having moderate left and mild right carpal tunnel syndrome confirmed by Nerve Conduction Studies ( NCS) performed February 10, 1998 and has undergone a surgical decompression procedure for the left carpal tunnel syndrome. The claimant has attributed his bilateral condition to the performance of his duties as a bus driver since 1975. His claim was initially accepted by claims but was denied at the Review Office, the second level of adjudication at WCB. The worker has appealed that denial.

In order for the claimant’s bilateral carpal tunnel condition to be accepted as an accident, it must be demonstrated on a balance of probabilities that the condition arose out of and in the course of employment, or as the claimant’s advocate has argued in the circumstances of this case as an enhancement of a pre-existing condition.

We have reviewed all the evidence, given at the hearing and received during the course of the hearing process and have concluded that the evidence supports a finding, on a balance of probabilities, that the claimant’s carpal tunnel syndrome is not associated with his work place activities. In coming to this conclusion we noted the following evidence:

  • the claimant submitted a claim to the WCB for bilateral carpal tunnel syndrome which he related to his duties as a bus driver and indicated that in these activities he used both complete arms and hands, he further indicated that he was right hand dominant, was taking thyroid medications and was 5 foot ten and weighed 245 lbs;

  • a WCB memorandum to file dated December 17, 1997 which was sought in response to the WCB’s request for information on the claimant’s specific job description and work history records that the claimant had no problems with his hands prior to 1997.

  • the memorandum further confirms that the symptoms were worse in the claimant’s non dominant left hand and that the claimant reported once again that he used both hands equally when driving buses and could not say that he used one hand more than the other;

  • the same memorandum records the claimant’s comments that all the buses have power steering and have had this for “at least twelve years”, that he had driven buses for this employer since 1975 and that prior to 1975 his past employment was as a driver but with different types of vehicles not buses. The claimant described which bus route he was on and indicated that he had driven a route for the last year and a half [prior to date of memo December 17, 1997] which was “ generally rut free and pothole free” with one avenue sometimes getting bumpy. The claimant further advised that this route was a very easy route and was not very strenuous which is why he had stayed on it for 1 ½ years;

  • an attending physician’s first report of injury dated October 24, 1997 confirms pain and numbness in both wrists left greater than right and diagnoses left carpal tunnel syndrome;

  • a WCB memorandum to file dated December 17, 1997 confirms again that the claimant uses both hands equally in his job, using his left to operate the door and his right to hand out transfers, that symptoms developed in June 1997, and that the claimant did not have any change in job duties or bus route. A WCB medical advisor when asked what was the most likely diagnosis responds “It may be CTS from history.” When asked to review the claimant’s job description with respect to a causal relationship to the condition the medical advisor responded “highly unlikely.”

  • Nerve Conduction Studies (NCS) performed February 10, 1998 confirmed “moderate left, mild right CTS.”

  • following the NCS results, the same WCB medical advisor, when asked whether the job duties would have caused the condition, responded “It could have caused the condition” and also states that “ as no external causes have been identified I would be prepared to authorize L side… .” (emphasis ours)

  • the claimant was seen by an attending occupational and environmental physician who in a report dated April 16, 1998 indicated “Thus it is likely that workplace factors contributed at least partially to the carpal tunnel syndrome that has resulted,” she further concludes on the basis of the evidence before her that “ workplace factors played at least a partial role if not a major role." She noted the claimant had had hypothyroidism for 8-10 years which she identified as a non-work related risk factor for the development of CTS but also indicated the hypothyroidism was currently well controlled. She also noted a family history of hypothyroidism and that the claimant “ had some peripheral edema and has been on diuretics, but no other chronic disease of note.”

  • on the recommendation of the occupational and environmental physician the claimant was referred to a specialist at the hand clinic with reference to the need for surgery. Specialists at the hand clinic indicated in a report dated June 8, 1998 that the claimant had, “established carpal tunnel syndromes bilaterally but both his symptoms and physical findings are more acute on the left side.” They further indicate that:

“ The more proximal Tinel’s seems to be adjacent to a transverse blood vessel at the wrist and therefore more proximal and careful exploration is required.”

  • we note that literature on “Repetitive Strain Injuries” authored by the above occupational and environmental health specialist submitted with this claim indicates at page 4:

“ … and certainly some medical conditions have also been associated with CTS, which must be ruled out. These include chronic disorders (including diabetes mellitus, hypothyroidism and gout… . Trauma, non-occupational activities, small wrist size and congenital anomalies must also be considered.” (emphasis ours)

  • following the left decompression surgery the hand specialist submitted a narrative report dated October 14, 1998 to the WCB which was not received until on or about November 30, 1998 in which the specialist indicated:

“ There was a strongly positive Tinel sign, which is actually 5cm. proximal to the carpal tunnel and extended distally into the tunnel giving rise to the suspicion that there was entrapment of the nerve by an anomalous muscle… . Accordingly, on September 15th, on a day surgery basis the nerve was explored. There were in fact two anomalous muscles; one a reverse palmaris longus that could produce some constriction to the nerve with an hourglass deformity of the nerve at that site. This was resected. There were also two anomalous muscle bellies of the flexor superficialis to both the left index and little fingers and these were retracted and sewn back onto themselves away from the nerve. In addition, a standard carpal tunnel release was performed. In addition, a full external neurolysis was carried out… .” (emphasis ours)

  • following the hearing, the Appeal Panel referred the file back to the WCB medical advisor who had given opinions on the file with respect to the claimant’s potential risk factors for the development of CTS and for his current opinion in light of the operative findings reported by the hand surgeon, the WCB medical advisor in a memorandum dated November 2, 1999 indicated in part:

“It is unfortunate that the information provided by Dr. [the hand specialist] in his narrative report but not received by the WCB until December 3 was not present on the file prior to the authorization [for surgery] being provided as it is clear from said report that the etiology of the carpal tunnel problem in fact relates to an anomalous musculature over the flexor aspect of the wrist. On a balance of probability, there is no causal relationship between this individual’s work activity and the development of the condition.”

  • with respect to the potential risk factors the WCB medical advisor indicates that the claimant’s body mass index represented a low risk in the development of CTS; that the hypothyroidism, in his opinion, was not a risk factor [as well controlled as shown by blood tests for the prior year ]; that the claimant’s age “by and of itself” was not a risk factor, and that with respect to oedema, upper extremity oedema might be significant but there was no wrist oedema documented on file.

  • the worker’s advocate asked for time to have the hand specialist comment on his operative findings, the hand specialist provided a report dated November 22, 1998. In this report the hand specialist indicates in part:

“ Mr. [the claimant] did have a strongly positive Tinel’s which indicates irritation of the nerve which was slightly proximal to the carpal tunnel and this made me suspect that the cause of the compression was not within the carpal tunnel itself, but due to some other form of compression in the distal forearm i.e. a vestigial muscle which is a congenital problem and which is in an abnormal site and therefore, causes compression as it gradually develops and enlarges…

It would be a gray area for the Worker’s Compensation Board to decide whether this is compensable or not… . It could be argued that the effects of work would cause the muscle to gradually hypertrophy and in turn eventually leads to compression although it would be difficult to prove this conclusively.”

With due respect to the arguments of the representatives for both the worker and the employer which have been ably presented to the panel by both parties, we find that the evidence supports a finding that the claimant’s bilateral carpal tunnel syndrome was not related to an accident which arose out of and in the course of employment or as a result of an enhancement of a pre-existing condition.

It is well documented in the literature submitted by both parties that carpal tunnel syndrome can be both work related and non work related and that the etiology can also be idiopathic. It is also well documented that there are identified risk factors which can contribute to the development of the condition. We also concur with the Review Office that it is generally accepted that in order for employment to be causal there must be high force, repetitive activities involving motions of the wrist of extreme twisting, gripping, pulling, pinching pressure and wrist extension and flexion.

We have reviewed this particular workers job description as submitted by the claimant to the WCB as recorded in memoranda to file and as presented to the Appeal Panel and have concluded that the job tasks as described do not constitute continuous highly repetitive, high force tasks such that would lead to the development of carpal tunnel syndrome. The duties as described are regular but also variable and periodic.

The claimant has acknowledged that for some time prior to the onset of symptoms he was driving a route that was not strenuous. We note that the claimant has driven buses and other vehicles before that for more than 22 years prior to the onset of symptoms which first occurred June 1997, relatively recently.

We concur with the employer that the literature supports a more likely onset in the dominant hand in relation to work activities and we note that the claimant has been shown to have a congenital condition in his non dominant hand in which an earlier and greater problem in symptomatology was confirmed clinically, by diagnostic testing and by the claimant.

In this regard the left operative procedure has revealed that the claimant had a congenital problem of anomalous musculature which was causing the compression of the nerve at the wrist and which necessitated surgical intervention. We find that the hand surgeon’s suggestion that this anomalous musculature could gradually hypertrophy from work to be speculative at best, especially as he himself indicated that “it would be difficult to prove this conclusively”, and that “this would be a gray area for WCB”. Therefore we find that we cannot place much weight on this area of speculation by the hand specialist.

We also note that some of the opinions on this file were necessarily given without any knowledge of the subsequent operative findings. We therefore place weight on the opinion of the WCB medical advisor, having reviewed the file in light of the operative findings, and as outlined in his report of November 2, 1999 where he indicates, that in his opinion, there is no relationship between the claimant’s work and the development of this condition.

We also recognize that the claimant has been identified to have risk factors for the development of CTS even if identified as low or even individually probably non-contributory. The WCB medical advisor has indicated that the claimant's body mass index represents a low but by implication not a zero risk. He has further identified that the claimant’s age by and of itself is not a risk factor; the claimant’s hypothyroidism with approximate onset since 1990 has been noted as a risk factor and discounted as the condition is well controlled with medication. A family history of hypothyroidism has also been documented and also that the claimant has been reported to have episodes of peripheral oedema for which medications have been prescribed. The claimant’s congenital condition would also be classified as a risk factor for the development of CTS.

We note notwithstanding their individual assessment these risk factors are occurring concurrently in the same individual along with a pre-existing congenital wrist condition around the time of onset of the claimant’s condition. We have concluded that the evidence in this case, on a balance of probabilities, supports a finding that this claim for bilateral carpal tunnel is not acceptable. Therefore the claimant’s appeal is denied.

Panel Members

D.A. Vivian, Presiding Officer
A. Finkel, Commissioner
R. Frisken, Commissioner

Recording Secretary, B. Miller

D.A. Vivian, Presiding Officer - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 22nd day of December, 1999