The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker appealed the Workers Compensation Board ("WCB") decision that their claim is not acceptable. A hearing took place on June 11, 2025 to consider the worker's appeal.

Issue

Whether or not the claim is acceptable.

Decision

The claim is not acceptable.

Background

The worker provided their Worker Incident Report to the WCB on October 31, 2023 reporting injury to both hands that occurred at work on February 28, 2023. The worker described feeling numbness and tingling in the fingers of both hands while at work, which progressed to experiencing those symptoms even away from work and related this to their repetitive job duties. The worker stated they did not initially report their difficulties as they did not understand what was happening until they sought medical treatment in May 2023, at which time the treating family physician diagnosed bilateral carpal tunnel syndrome (“CTS”). The worker reported seeing a hand specialist on October 30, 2023 who diagnosed severe carpal tunnel syndrome and that, after attempting to work for 1.5 hours that day, they experienced numbness and tingling in their hands and left work.

The WCB received a May 4, 2023 chart note from the treating family physician noting the worker reported numbness and tingling upon waking, in their right hand "for a while now", with clinical findings of no atrophy, 5/5 power, normal pulse and a negative Tinel test. The physician also noted scarring from a previous trigger finger surgery. The physician diagnosed CTS and recommended a nerve conduction study, use of a wrist splint and refilled a prescription for a topical pain relief medication. In a handwritten note dated November 1, 2023, the physician indicated the worker also reported the same symptoms with their left hand.

The WCB also received a report from the neurologist who conducted a nerve conduction study of the worker’s right hand on October 6, 2023. The neurologist noted the worker’s report of “paresthesia and stiffness of the hands for approximately one year, worse when [the worker] wakes up in the morning.” The study findings indicated severe right CTS. An October 18, 2023 report from the same neurologist indicated findings of moderate to severe left CTS.

The WCB also received further nerve conduction study results from another neurologist dated October 30, 2023. The second neurologist noted the worker’s report that their symptoms began over 9 months earlier, and that they experienced paresthesia and numbness involving the whole hand, worse on the right than the left hand. The neurologist noted strength of 5/5, equal bilaterally, normal tone bilaterally and reflexes graded at 1/2, equal bilaterally, with a positive Tinel’s sign at the left wrist, and mild sensory loss in the median distribution of the hands. The EMG study findings indicated evidence of “severe carpal tunnel syndrome on the right and at least moderate [CTS] on the left.” The neurologist recommended wrist splints to be worn at night for 4 to 6 months and a referral for surgery.

On November 2, 2023, the employer provided an Employer's Accident Report confirming the worker’s report of October 30, 2023 that they began to feel numbness and tingling in their hands while working. The employer noted that October 30, 2023 was the first day following the worker’s two-week vacation and that the worker reported issues with their hands and left work after 1 hour. The employer also indicated the worker had not previously reported any difficulties with their hands.

On November 9, 2023, the worker advised the WCB that their symptoms began with numbness in their hands sometime in February 2023, which started getting worse as they constantly worked with their hands. The worker stated they are right hand dominant, and that their right hand symptoms are worse than the left, but they noticed the symptoms in both hands at approximately the same time. The worker provided details of their job duties, which require them to lift boxes of varied sizes and weights by gripping and lifting the boxes from underneath. The worker advised they believe they do not have strength to grip objects with their hands and that they feel those symptoms all day, especially when waking. The worker noted they performed the same job duties for 47 years.

The employer provided further information on November 9, 2023, including a Functional Abilities Form, completed by the worker's treating physician on November 1, 2023 indicating the worker was unfit for work for an unknown period of time. On November 10, 2023, the employer provided the WCB with the Physical Demands Profile and job description for the worker's position.

A WCB plastic surgery consultant reviewed the worker’s claim on November 19, 2023. The consultant noted the diagnosis of bilateral CTS, greater on the right and outlined the medical guidelines in relation to development of occupational CTS. The consultant concluded the medical evidence on file did not support a finding of total disability and that typical restrictions for carpal tunnel syndrome involve avoiding/limiting repetitive firmly resisted grasping. They also determined that the file documents did not indicate any significant pre-existing condition.

On November 27, 2023, the WCB advised the worker that the claim was not acceptable as it could not establish a causal relationship between the worker's hand difficulties and their job duties or any incident at work.

The worker's treating plastic surgeon provided a letter dated December 7, 2023 in support of the worker's claim that their CTS diagnosis was a job-related injury, noting the worker had "…both clinical and electrophysiological evidence of carpal tunnel syndrome" and that based on the worker's job description, they believed the worker’s job duties could have caused or exacerbated the worker's CTS. On December 12, 2023, the WCB wrote to the worker confirming the additional information was reviewed and there was no change to the earlier decision.

On March 27, 2024, the worker requested Review Office reconsider the WCB's decision to deny their claim. In their submission, the worker noted the only non-work related risk factor for development of CTS was their age, and restated their belief that more than 40 years performing the same job duties for the employer led to the development of CTS. On June 14, 2024, Review Office determined the worker's claim was not acceptable. The worker's representative filed an appeal with the Appeal Commission on February 18, 2025.

Reasons

Applicable Legislation and Policy

The Appeal Commission and its panels are bound by the provisions of The Workers Compensation Act (the "Act"), regulations under that Act and the policies established by the WCB's Board of Directors. The provisions of the Act in effect as of the date of the worker’s accident are applicable.

The Act sets out the definition of an accident in s 1(1) as including:

(a) a chance event occasioned by a physical or natural cause, 

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

(c) an event or condition, or a combination of events or conditions, related to the worker's work or workplace, 

that results in personal injury to a worker, including an occupational disease, post-traumatic stress disorder or an acute reaction to a traumatic event.

A worker who is injured as a result of an accident at work is entitled to benefits under s 4(1) of the Act.

The WCB has established Policy 44.10.20.10, Pre-Existing Conditions (the “Policy”) which provides that “The fact that the worker has a pre-existing condition does not disentitle them to compensation for their workplace injury. However, the workers compensation system is designed to compensate workers for workplace injuries, not all injuries. It is often necessary, therefore, to distinguish between a worker's pre-existing condition and their workplace injuries.” The Policy defines pre-existing condition as:

…any medical condition the worker had prior to their workplace injury. Pre-existing conditions may contribute to the severity of a workplace injury or significantly prolong a worker's recovery. Workplace injuries can also have an effect on pre-existing conditions. When a worker’s pre-existing condition is temporarily worsened because of a workplace injury, this is considered an aggravation of a pre-existing condition. When a worker’s condition is permanently worsened because of a workplace injury, this is considered an enhancement of the pre-existing condition.

Worker’s Position

The worker appeared in the hearing with a worker advisor. The worker advisor provided an oral submission on behalf of the worker, and the worker provided testimony through answers to questions posed by their representative and members of the appeal panel.

The worker’s position is that as a result of the various repetitive tasks they undertake in the course of their employment over the many years of that employment, including lifting, grabbing, holding and lifting items of various sizes and shapes, in a cold environment during three out of five of their weekly shifts, they developed bilateral carpal tunnel syndrome early in 2023, which worsened as they continued to work until October 30, 2023. As such, the worker believes their claim should be accepted as an injury arising out of and in the course of their employment, and the appeal should be granted.

The worker advisor also submitted, in the alternative, that the worker’s claim should be accepted as an aggravation or enhancement of a pre-existing condition.

Employer’s Position

The employer was represented in the hearing by an advocate who made an oral submission on behalf of the employer.

The employer’s position is that the worker’s claim should not be accepted as the evidence does not support a finding that the worker’s bilateral CTS arose out of the performance of their job duties, which do not involve or require the degree of high force, high repetition hand motions or awkward postures as are known to increase the risk of developing occupational CTS.

Analysis

The issue for the panel to determine is whether the worker’s claim is acceptable. For the worker’s appeal to succeed, the panel would have to determine on the standard of a balance of probabilities that the worker was injured as a result of an accident as defined by the Act, arising out of and in the course of their employment. In other words, we must find that it is more likely than not that the worker sustained an injury caused by an event or condition, or a combination of events or conditions, related to the worker's work or workplace, for the claim to be acceptable. The panel was unable to make such a finding for the reasons detailed below and therefore concludes that the worker’s claim is not acceptable.

This is an appeal about the worker’s development of bilateral CTS, which they believe developed as a result of their participation in their various job duties over the course of more than 45 years. The panel accepts and relies upon the medical evidence that confirms diagnosis of bilateral CTS, supported by the diagnostic testing in October 2023. We note that the diagnosis is severe CTS on the right and at least moderate CTS on the left hand.

In considering whether the worker’s diagnosis of bilateral CTS is causally related to participation in their employment activities, the panel reviewed the medical opinions and reports. We noted that the only report indicating a causal relationship between the worker’s diagnosis and their job duties is the treating plastic surgeon’s letter to the WCB advocating for a review of the claim denial, dated December 7, 2023. In that letter, the surgeon set out that the worker’s job duties “…certainly could have caused…carpal tunnel syndrome and at the very least, have exacerbated them.”

The WCB’s plastic surgery consultant set out in their opinion of November 19, 2023, that they consulted the AMA Guides to the Evaluation of Disease and Injury Causation (2014), an evidence-based review of the medical literature regarding a variety of conditions, including CTS and that the AMA Guides conclude, with respect to CTS:

• That there is very strong evidence that work duties involving a combination of i) force and repetition or ii) force and posture represent risk factors for CTS…. 

• That highly repetitive work alone had “conflicting (insufficient) evidence” to categorize such duties as a risk factor for CTS; 

• That awkward postures alone were considered low risk; and, 

• That there is insufficient evidence to relate keyboard activities as a risk factor for CTS.

The WCB plastic surgery consultant further outlined that the AMA Guides indicate that many of the reviewed studies on CTS define high force, high repetition and awkward posture as follows:

• High force was defined as more than 4 kilograms of force (per hand); 

• High repetitions was defined as a cycle time of less than 30 seconds or alternatively, more than 50% of the cycle time involved in performing fundamentally the same activity; and 

• Awkward posture was defined as more than 45 degrees of wrist flexion or extension without excessive radial or ulnar deviation.

The panel accepts and relies upon this evidence as a scientific basis upon which to establish an occupational cause for the development of CTS. We therefore considered these parameters in relation to the Physical Demands Profile for the worker’s job as provided by the employer to the WCB and relied upon by the parties in the hearing. The panel also considered the worker’s testimony and information provided to the WCB in relation to how they do their job, noting that both the worker and employer confirmed there were no changes in the worker’s job duties in early 2023, and that the worker had been doing the same job over the course of more than 45 years at the time of symptom onset. The panel further noted the evidence that the worker is right hand dominant and that the worker described symptom onset in their right hand initially, but soon after, bilateral symptoms, and that the worker’s job duties require use of both hands. 

Considering the totality of the evidence, the panel is not satisfied that the worker’s job duties involve the required combination of repetitious and forceful gripping, or forceful gripping with awkward wrist postures as are known to increase the risk of development of CTS. While the panel agrees that the worker’s job duties do involve a variety of wrist and hand movements that require gripping and repetitive activities as well as some awkward wrist positions, the evidence does not establish that these activities involved sufficient force, repetition, or use of awkward positioning so as cause development of bilateral CTS as defined in the AMA Guide relied upon by the WCB plastic surgery consultant. In particular, the panel noted that the worker’s duties in each shift include a variety of tasks, and that the gripping and lifting and carrying tasks all involve a variety of sizes and weights of items gripped, lifted, and carried. While the panel agrees that these tasks consume a significant portion of each shift, we note the worker also must necessarily intersperse those activities with other tasks such that the evidence does not support a finding that the job duties as a whole involve high force and high repetition, nor high force and awkward positioning as defined in the AMA Guides.

In reaching this conclusion, the panel also considered the brief opinion provided by the treating plastic surgeon in support of the worker’s claim. We noted the opinion outlined is based on a description of the job duties but does not reference the detailed requirements set out in the Physical Demands Profile, and further, it provides only that there could be a causal relationship between the duties described by the worker and their diagnosis. The standard of balance of probabilities requires that the panel be satisfied that it is more likely than not that there is such a causal relationship; therefore, it is not sufficient to find only that a causal relationship is possible. As such, this opinion, while supportive of the worker’s appeal in general, does not persuade the panel based on the totality of the evidence considered.

The panel is also satisfied that the evidence does not support the worker’s alternative position that their job duties caused an aggravation or enhancement of a pre-existing condition. We noted that the treating family physician indicated the worker’s symptoms first arose at some point early in 2023 and further, that the diagnosis of bilateral CTS was proposed in May 2023 and confirmed in October 2023. While the treating plastic surgeon suggested the job duties could cause exacerbation of a pre-existing condition, they did not outline any basis for that opinion nor confirm the existence of such a condition, and as such, the panel gives little weight to this conclusion, unsupported by other evidence. We also note the WCB plastic surgery consultant’s conclusion that the evidence does not support that the worker had any significant pre-existing condition.

Considering the totality of evidence before us and on the standard of a balance of probabilities, the panel is unable to find that the worker sustained injury arising out of and in the course of their employment. Therefore, the worker’s claim is not acceptable, and the appeal is denied.

Panel Members

K. Dyck, Presiding Officer
J. Peterson, Commissioner
M. Kernaghan, Commissioner

Recording Secretary, J. Lee

K. Dyck - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 16th day of June, 2025