The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

An Appeal Panel hearing was held on May 6, 2003, at the request of a union representative, acting on behalf of the claimant. The Panel discussed this appeal on May 6, 2003 and again on June 9, 2003.

Issue

Whether or not the claim is acceptable.

Decision

That the claim is acceptable.

Background

In July 2001, the claimant contacted the call center at the Workers Compensation Board (WCB) to file a claim for compensation benefits relative to carpal tunnel syndrome (CTS), which she related to work activities as a customer service representative. The claimant noted that she worked at a call center and that she received about 100 calls per day. She used six computer applications in her work and was continually using a mouse and keyboarding. It was the occupational health nurse's opinion that her work station was not ergonomically correct.

In order to adjudicate the claim, a WCB adjudicator spoke with the claimant on October 3, 2001 to gather additional information regarding her work history with the accident employer, details concerning her job duties, the onset of her hand difficulties, reporting of the accident, medical treatment she received, etc.

On October 17, 2001, the employer's representative provided the WCB with medical literature pertaining to the topic of CTS. The employer was opposed to the acceptance of the claimant's CTS condition as being a consequence of her employment. In further correspondence dated December 10, 2001, the employer's representative submitted a work station assessment with respect to the claimant. He suggested that the claimant's duties did not require 'high force repetitive activity involving motions of the wrist such as twisting, gripping, pulling, pinch pressure and wrist flexion/extension.'

On January 17, 2002, the WCB adjudicator again contacted the claimant to clarify certain aspects of her job duties. The adjudicator also confirmed with the claimant's supervisor the job duties performed by the claimant.

Following consultation with a WCB medical advisor on February 4, 2002, primary adjudication advised the claimant on February 6, 2002 that her claim was not acceptable. Primary adjudication stated that it was unable to establish an exposure to significant work related factors in the development of her CTS and could not relate her condition to her work activities. On July 3, 2002, the claimant's union representative appealed this decision to primary adjudication and, as primary adjudication found no basis to rescind its previous decision, the case was forwarded to Review Office for consideration.

On November 15, 2002, Review Office considered all file information which included a submission by the employer's representative dated August 12, 2002 and a further submission from the union representative dated September 23, 2002. Review Office ultimately determined that the claim was not acceptable.

Review Office noted that there was a general consensus regarding the nature of the work duties performed by the claimant and there was no debate that the claimant suffered from right CTS. There was, however, much debate in the medical community regarding the role of work duties in the development of CTS.

Review Office was of the view that the activities of keyboarding and general computer usage was not causative in the development of CTS as it was generally accepted by the WCB that for a claim to be approved it must be shown that the job duties of the worker must involve repetitive flexion and extension of the wrist against resistance. Accordingly, the worker's appeal was denied.

On May 6, 2003, an oral hearing was held at the Appeal Commission at the request of the union representative who appealed Review Office's decision. Following the hearing and discussion of the case, the Appeal Panel obtained a general information package that was prepared by the medical advisor with the Office of the Registrar with respect to CTS, along with a study entitled, "The Frequency of Carpal Tunnel Syndrome in Computer Users at a Medical Facility." Both the union and employer representatives were provided with a copy of this information package and were asked to provide written comments to the Panel. On June 9, 2003, the Panel met further to discuss the case and took into consideration submissions from the union and employer respectively dated May 21, 2003 and May 22, 2003.

Reasons

Chairperson Williams and Commissioner Day:

This is a case of two analytical solitudes.

a. The Claimant's Perspective

The claimant emphasized the temporal relationship between her injury and a change in the nature of her job. In her oral testimony, she dated the onset of her symptoms to a material change in her duties as a customer service representative in June, 2000. Her representative argued that "the switch of duties, along with the staffing shortages within the branch greatly increased the volume of work that the claimant was required to perform at that time." Only a few months later in November 2000, she was diagnosed with right CTS. In her oral testimony, she noted that she now experiences some difficulty with her left hand and wrist but that the situation remains worse on her right.

The claimant emphasized the dramatic change in her workload on a daily and annual basis that began in June, 2000. "Day-to-day inquiries just increased dramatically" and now its "12 months of the year where we (are) busy".

The claimant's new workplace reality meant that she spent between 70 and 80 percent of her day on the computer. While she averaged about 90 calls a day, her daily volumes have gone as high as 137 calls. Her duties involved both a significant degree of typing and frequent mousing using her right hand. On any given call, as many as six computer applications might be required. Unfortunately, as the Occupational Health Nurse observed in a 4/01 interoffice memorandum, "she (did) not always take her breaks at the assigned times".

An assessment of her workplace identified a number of problems with both the ergonomics of her work station and her work pattern. Once the claimant took action to increase her rest period between calls as well as to place her arms and wrists in a more relaxed position and to minimize the strain associated with reaching for her mouse, her problems improved somewhat.

The claimant's conclusions as to the causal relationship between her workplace and her injury were supported by her orthopaedic surgeon who noted that her work required a repetitive or sustained hand grip as well as a flexion or extension of her wrists. In his mind, there was "no doubt" that her injury was related to repetitive movement of the wrist. The orthopaedic surgeon ruled out other potential causes of her injury. He noted that her avocational interests did not involve repetitive use of the hands and that the claimant had no past history of diabetes, hypothyroidism, rheumatoid arthritis, collagen vascular disease, obesity or pregnancy. In his view, "I cannot see the patient has any condition other than repetitive movement to cause this median entrapment at the wrist."

In his representations to the panel, the claimant's representative also made reference to a number of scientific articles which he interpreted to suggest that "repetitive, prolonged and intense use of computers along with work stations that are not ergonomically correct and the absence of proper work rest cycles are all contributing factors in the development of carpal tunnel syndrome." In his view, these factors led directly to the claimant's carpal tunnel syndrome.

b. The Employer's Perspective

The representative of the employer begged to differ.

In his submission, he asserted that "the balance" of the occupational medical literature reported no correlation between repetitive workplace duties such as typing/keyboarding and the production of carpal tunnel syndrome. While he acknowledged that there is no unanimous opinion on the topic he noted that it goes without saying that, regardless of the medical issue, there will always be differing opinions relating to the etiology of same. He took the position that it was incumbent upon the users of this epidemiological evidence to determine both the conclusiveness and credibility of each available study and reiterated his opinion that the preponderance of credible evidence refuted the purported relationship between the development of carpal tunnel syndrome and computer usage.

The employer's representative felt his views were buttressed by the opinion of two physicians from the Board who reviewed the file and concluded that there was no relationship. He pointed out that a large number of CTS cases were idiopathic in nature and that the absence of identifiable avocational and biological causes did not lead invariably to the conclusion that the workplace had caused the injury.

The employer's representative rejected the characterization of the claimant's duties as requiring a repetitive or sustained hand grip and suggested that if the claimant's work was a contributing factor, the condition would have appeared many years previously.

c. The Empirical and Medical Evidence

The analysis and literature presented to the panel offered a widely divergent spectrum of views on the relationship between CTS and work and in particular, on the correlation between CTS and typing/keyboarding work. In the words of one expert, the body of literature is "deeply polarized and lacks consensus." Neuromusculoskeletal Conditions of the Upper Extremity: Are They Due to Repetitive Occupational Trauma/ (2000, p. 686).

While the employer's representative asserted that the balance of the occupational medical literature reports no correlation between repetitive workplace duties such as typing/keyboarding and the production of carpal tunnel syndrome, our review of the evidence has not led us to the same conclusion.

Some of the material reviewed raises concerns in terms of its methodology or its inconsistency with clinical reality (Carpal tunnel syndrome study stirs controversy in the Lancet, 2001) while other materials cited do "not specifically address the effect of occupational hand use" (Natural History of Median Nerve Sensory Conduction in Industry: Relationship to Symptoms and Carpal Tunnel Syndrome in 558 Hands over 11 Years (November 1997).

Just as importantly, there are a number of studies before the panel which would appear to come to a different conclusion as to the correlation between CTS and typing/keyboard work. (Carpal Tunnel Syndrome: what is attributable to work?, The Montreal Study (1997), Surveillance of Work-Related Carpal Tunnel Syndrome in Massachusetts 1992- 1997 (2001), Risk Factors for Musculoskeletal Disorders among Computer Users (1999) and Carpal Tunnel Syndrome as a Repetitive Motion Disorder, (1998).

We would note that some studies point to a spectrum in terms of the relative frequency of carpal tunnel syndrome in the workforce. This literature suggests that the prevalence of was lowest among workers on "low force-low-repetitiveness" jobs and highest among workers on "high-force, high repetitiveness jobs" with repetitiveness appearing to be a stronger risk factor than force. (Occupational Factors and Carpal Tunnel Syndrome, p. 353) That being said, it appears difficult to determine from the empirical studies a particular volume for a particular person at which a particular repetitive use may constitute a hazard. As the general text points out, "little is known about the degree and duration of wrist and hand activity needed to cause synovial changes in the carpal tunnel." Carpal Tunnel Syndrome and Other Disorders of the Median Nerve, (1993, pp. 245 and 242) See also Neuromusculoskeletal Conditions of the Upper Extremity: Are They Due to Repetitive Occupational Trauma, (2000, p. 682)

While our analysis should be guided by the wider body of scientific literature, it also requires consideration of the specific situation of the claimant. In the words of an expert whose article was cited with approval by both parties: "Generalizations based on assessment of relative risks and statistical trends, while adequate for summarizing the large population experience may contain information, which when applied at the individual level, could result in erroneous determinations as to causation." Neuromusculoskeletal Conditions of the Upper Extremity: Are They Due to Repetitive Occupational Trauma, (2000, p. 689).

The expert recommended "applying a common sense approach to each worker's problem" to override "the fluctuating currents of philosophic thought and avoid reacting to sweeping statistical, philosophic and partisan generalizations." (p. 689)

His words echo the advice of the majority of the panel in Decision 47/96. "We do not accept the argument that CTS is solely an occupational disease and we equally reject the argument that CTS is solely an ordinary disease of life. The litany of medical literature and medical opinion presented to the Panel has led us to conclude that CTS can be work related and also non-work related. Each case must be decided, on a balance of probabilities, in accordance with its own unique set of facts." (p. 22)

It is noteworthy that similar advice was offered in another paper replied upon by the employer's representative. While the author of that particular paper remained to be convinced of the statistical relationship between CTS and computer key pad use, he suggested that "where a clear temporal linkage between the development of symptoms and their relief, in relation to a given exposure can be reliably and repeatedly identified, then a major criterion for causality may be met." (Carpal Tunnel Syndrome, discussion paper prepared for The Workplace Safety and Insurance Appeals Tribunal, 2001, p. 3/10)

A general reference on CTS offers similar advice. "The temporal relationships between the suspect activities and symptoms of carpal tunnel syndrome often provides the best clues to answering the difficult question of causation." "Timing of symptoms in relation to changes in job tasks, vacations, days off and changes in employment can be relevant." Carpal Tunnel Syndrome and Other Disorders of the Median Nerve (1993, p. 246)

Given this analysis, it is worth noting that the material change in the claimant's job duties which took place in June, 2000 does not appear to be have been noted in the WCB assessment of the case. There is no reference to the dramatic increase in work load in the October 3, 2001 or Jan 17, 2002 memos of the adjudicator. Likewise, while the reference to the WCB specialist dated September 26, 2002 mentions that the Claimant had worked as a customer service representative since November 1998, there is no reference to the change in the nature of her duties shortly before her condition was diagnosed. The weight given to the advice of the Board physicians must be tempered by the fact that they do not appear to have been aware of the material change in the claimant's duties which took place in June, 2000.

d. Conclusions

We are satisfied, on a balance of probabilities, that the claimant's work duties are responsible for her CTS. In making this decision, we place particular emphasis on the material change in the claimant's work duties in June, 2000 which bears a close temporal relationship with her diagnosis with CTS. Based upon her evidence which we accept, there appears to have been a "dramatic" upsurge in her volume of work. We note that the claimant's duties involved a significant volume and duration of keyboarding and mousing in which she used both hands for keyboarding and her right hand for mousing. Although we make no finding on this point, it may be that the more extensive difficulties with her right hand stem from her frequent use of the mouse.

Our conclusion is reinforced by the roughly contemporaneous evaluation of her workplace which identified problems both with her work station and her work patterns. We would note that the claimant's symptoms abated somewhat after certain ergonomic corrections were made and the claimant began to take more frequent rest breaks.

We also placed weight on the orthopaedic surgeon's evaluation of the factors which put the claimant at risk. He specifically considered and rejected a number of biological and avocational triggers and pointed to the claimant's work activities as the likely cause of her injuries.

After weighing the entirety of the record, the WCB files, the evidence of the worker, and the able submissions of both representatives, we find that on the balance of probabilities, the claimant's work duties are causally related to her injuries and her claim is therefore acceptable.

Panel Members

B. Williams, Presiding Officer
A. Finkel, Commissioner
M. Day, Commissioner

Recording Secretary, B. Miller

B. Williams - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 22nd day of July, 2003

Commissioner's Dissent

Commissioner Finkel’s dissent:

The claimant in this case has asserted that her bilateral carpal tunnel syndrome (CTS) has arisen out of her job duties as a call center representative with the employer. Her claim has been denied at the adjudicative and review levels of the Workers Compensation Board (WCB) and she has appealed those decisions to this panel.

Sections 1(1) and 4(1) of the Workers Compensation Act set out the circumstances under which claims for injuries can be accepted by the Board, and state that the worker must have suffered an accident that arose out of and in the course of his employment. Once such an accident has been established, the worker would then be entitled to the benefits provided under the Act.

In order for this worker’s claim to be acceptable, I would have to find that the claimant’s bilateral carpal tunnel syndrome is indeed causally related to her employment. I have carefully reviewed the evidence available in the file and presented at the hearing, and have concluded on a balance of probabilities that the claimant’s job duties would not have resulted in the development of a bilateral carpal tunnel syndrome. In reaching this conclusion, I have placed particular weight on the following evidence:

• The claimant describes her job as answering telephone calls with a headset at a call centre from customers. From 1998 – 2000, she responded to billing inquiries and arranged payment schedules. In 2000, she moved to a new position where she dealt with general inquiries related to municipal services, including recycling, garbage, and water repairs. While on the telephone, she uses her computer to bring up information, to record the call, and to ensure that the appropriate follow-up actions are taken by the responsible department. The claimant handles 75-100 calls per day. Each call averages four minutes in length, with a one minute break between each.
• Up to six computer programs are used each day, accessed by a mouse used in her right hand. The claimant’s evidence is that she clicks into the programs as she interviews the caller. The typing (use of both hands) for an average call occurs when she types in the caller’s address in one of the screens, and later types a brief computerized report. At the hearing she described a typical memo as follow: “ ‘Resident has phoned. Blue box was out on time. Sorted as usual. Please check out the information.’ Then I put in your name and address, your telephone number.” Following that message, two more clicks are required to complete the computer activity.
• The claimant’s condition developed in both wrists at the same time, becoming very noticeable in late 2000, with symptoms greater in the right wrist than the left. The evidence does not disclose any significant change in job duties at the workplace before or around the time that the condition arose bilaterally in the claimant’s wrists.
• The claimant worked at a workstation that required some ergonomic changes. I note, though, the claimant’s evidence at the hearing that her wrists are in the same position keyboarding currently as they were before the ergonomic changes, suggesting that any deficiencies in the workplace setup were not factors in the development of CTS .
• Medical literature suggests that high force/high repetition activities or those involved with awkward bending of the wrist or forceful pinching and gripping can be associated with the development of carpal tunnel syndrome. Of decreasing causal significance are high force/low repetition activities, followed by low force/high repetition activities. Keyboarding falls into this last category. The specific role of keyboarding has been reviewed in the medical literature, and a package of medical literature was distributed to the parties for comment in this regard. This material augmented the general articles on CTS and its causes that had been presented by the parties. Of particular interest is a literature review, “Risk Factors for Muscoloskeletal Disorders among Computer Users (Tittiranonda, Burastaro, Rempel, 1999), as it points to very high levels of keyboarding activity as being necessary to be a possible cause of CTS. The authors suggest that “When operating a keyboard, repetitive key entry (50,000-200,000 keystrokes per day may cause irritation to the membranes surrounding the extensors tendons (synovial sheaths) or the tendons themselves…” (page 28).
• The medical literature also notes that carpal tunnel syndrome can arise from a number of other known factors (which are not present in this case), and that perhaps 50% of diagnosed CTS cases can be idiopathic (unknown cause) in origin.
• Dealing with the medical opinions on this file, I note that the only supporting medical opinion of the work-relatedness of the claimant’s bilateral CTS condition is that provided by her treating orthopaedic surgeon. He describes her job as “++ typing involved” in a CTS questionnaire prepared on October 16, 2001, and later states “No doubt this is related to repetitive movement of the wrist as the patient works in computer and typing for the last 20 years” in a letter dated May 15, 2001.
• However, these impressions of the claimant’s job do not correlate with her evidence; the typing is intermittent and brief, going back and forth between the mouse and keyboard, and the volume of typing is very low in each call. In comparing the actual volume undertaken by the claimant to the volumes that the medical literature proposes as being necessary, I note that the volumes of keyboarding activities undertaken by the claimant are far, far below the 50,000-200,000 keystrokes suggested in the medical literature.
• A WCB medical advisor reaches a similar conclusion, on the facts of this case, in a memo dated February 4, 2002, stating: “The balance of occupational medical literature reports no correlation btw repetitive workplace duties such as typing/keyboarding and the prod’n of CTS. What is accepted is the use of the hands, wrists, in altered pos’n, against force, or concomitant use of power or vibratory tools – none of which apply to this clmt.”
• As well, the Acting Head of WCB Healthcare Services has reviewed this file, and states in an undated memo:

“In reality CTS is in many parts of the world considered idiopathic with no identifiable causation. It is true that repetitive stressful work against force can cause the condition. Many computer operators complain of the condition and such claims often seem to be accepted notwithstanding the fact that their regular work duties do NOT have the required evidence of causation. However acceptance of a claim is an adjudicative decision and not the responsibility of the [unfinished sentence].

In this case in my opinion the appropriate criteria have not been met. The fact that no other causes have been identified is irrelevant given my initial comment that the condition is widely held to be idiopathic.”

In this particular case, based on my review of the evidence, I find that the claimant’s job duties do not involve a volume of keyboarding sufficient to have triggered the development of a bilateral carpal tunnel syndrome. I therefore conclude, on a balance of probabilities, that the claimant’s development of a bilateral carpal tunnel syndrome was not caused by the claimant’s performance of her job duties, and that her medical condition did not arise out of and in the course of employment, as required by the Act. On this basis, I find that the claim is not acceptable, and would deny the claimant’s appeal.

A. Finkel, Commissioner