The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker is appealing the decision made by the Workers Compensation Board ("WCB") that his claim is not acceptable. A hearing was held on February 28, 2018 to consider the worker's appeal.

Issue

Whether or not the claim is acceptable.

Decision

The claim is acceptable.

Background

The worker filed a Worker Incident Report on December 4, 2014 reporting an injury to both his wrists, described as:

I have to use power tools about once or twice per week.

I drive a grader for 10-12 hours per day that includes overtimes, I drive the grade (sic) for at least eight hours per day. I feel this is causing my injury. I have to always pulling (sic) levers with both hands every couple seconds.

The worker had attended at the emergency room of the hospital on October 7, 2014 and was diagnosed with "CTS (carpal tunnel syndrome)" and was referred for a nerve conduction study.

The nerve conduction study was conducted on November 3, 2014 with the following conclusions:

Abnormal study. 

Moderate impairment of Median conduction across both wrists. The electrodiagnostic criteria for Carpal Tunnel Syndrome were fulfilled bilaterally. 

The findings were discussed with the patient. Treatment including surgical release and medications for neuropathic pain were briefly discussed. He will follow-up with his primary care physician.

The worker was examined by his primary care physician who provided the following medical note:

The above named 46 year old male has been diagnosed with Moderate impairment of median conduction across both wrists.

Investigations were carried out and the electrodiagnostic criteria for Carpal Tunnel Syndrome were fulfilled bilaterally.

It appears that the etiology (cause) of his symptoms and signs may well be related to constant vibration when operating a grater (sic) six to eight hours per day.

He will be referred to a plastic surgeon and has an appointment on January 13, 2015 and will likely require bilateral surgery which will likely impair his ability to return to full duties involving use of his hands.

On December 17, 2014, the worker discussed the nerve conduction study with his primary care physician. The worker was diagnosed with bilateral moderate carpal tunnel syndrome and referred for surgery.

The WCB medical advisor provided the following opinion on December 22, 2014:

The file was reviewed. I was not able to determine from the description on file whether those tasks would be associated with the development of carpal tunnel syndrome.

Carpal tunnel syndrome most often arises idiopathically. There has not been a well demonstrated relationship between any job tasks and the development of carpal tunnel syndrome. There is felt to be some relationship between job tasks involving highly repetitive forceful grasping carried out over a significant part of the day. An example of such tasks would be prying forcefully with pliers on an assembly line, uninterrupted for a significant part of the day.

The WCB advised the worker on December 29, 2014 that his claim was not acceptable as it could not establish a link between the worker's condition and an accident as defined under the Act. The WCB noted:

Carpal Tunnel Syndrome is considered to be a condition that can develop from both work related and non-work related risk factors. The accepted work related risk factors would include jobs requiring highly forceful and repetitive activity involving motions of the wrist such as twisting, gripping, pinch pressure, as well as repetitive/forceful wrist flexion/extension. An example would be prying forcefully with pliers on an assembly line uninterrupted for a significant portion of the day.

There are also a number of non-work related risk factors that can include, but are not limited to obesity, skeletal injury to the wrist, age, gender, smoking, caffeine intake and idiopathic origin (unknown case/origin).

It is difficult to account for the onset of symptoms in relation to the low force demand duties of operating a grader which have been performed for many years without incident. The new inciting incident or influence which "triggered" the onset of symptoms is not apparent. In particular, a specific provocative workplace factor is not recognized.

The worker's representative requested reconsideration of the WCB's decision on February 15, 2017 and submitted further medical evidence. The worker's representative felt that the worker's claim should be accepted as the worker was exposed to a number of wrist factors through his job duties which was felt to be responsible for the onset and progression of the worker's carpal tunnel syndrome.

On May 2, 2017, the WCB advised the worker that they had conducted a review of his claim, including obtaining further information regarding his work activities. Based on their review it was determined that there was no new evidence provided and their previous decision remained unchanged. The worker's representative requested consideration of the WCB decision by the Review Office on June 13, 2017 as it was felt the physical demands of the worker's job duties including "prolonged exposure to vibration, as well as repetitive and forceful gripping" contributed to the worker's development of bilateral carpal tunnel syndrome.

Review Office upheld the WCB's decision on August 16, 2017. Review Office relied on a WCB medical advisor's report dated April 27, 2017 which provided:

There is some weak evidence that vibration may be associated with the development of carpal tunnel syndrome. Where this issue has been studied, the source of the vibration has most often been handheld vibratory tools where the exposure has been applied without interruption for considerable periods of time.

The vibration associated with the controls described in this case would likely be of considerably lower magnitude compared with a handheld vibratory tool. In addition, the development of bilateral carpal tunnel syndrome in a given individual is regarded as evidence that the condition is idiopathic.

Review Office acknowledged that some parts of the worker's job duties involved vibration however, did not find that the vibration was sufficient enough in volumes to cause the worker's bilateral wrist issues.

The worker's representative filed an application with the Appeal Commission on August 17, 2017. An oral hearing was held on February 28, 2018.

Reasons

Applicable Legislation and Policy:

The Appeal Commission and its panels are bound by The Workers Compensation Act (the “Act”), regulations and policies of the Board of Directors.

Subsection 4(1) of the Act provides that where a worker suffers personal injury by accident arising out of and in the course of employment, compensation shall be paid to the worker by the WCB.

The term “accident” is defined in subsection 1(1) of the Act as follows:

(a) willful 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

(iii) an occupational disease,

and as a result of which a worker is injured.

WCB Policy 44.10.20.10, Pre-Existing Conditions (the “Policy”) provides that a claim can also be accepted if there is a work-related aggravation or enhancement of a pre-existing condition. That Policy states:

The Workers Compensation Board will not provide benefits for disablement resulting solely from the effects of a worker’s pre-existing condition as a pre-existing condition is not “personal injury by accident arising out of and in the course of employment.” The Workers Compensation Board is only responsible for personal injury as a result of accidents that are determined to be arising out of and in the course of employment. The 

Policy further provides:

When a worker’s loss of earning capacity is caused in part by a compensable injury and in part by a non-compensable pre-existing condition or the relationship between them, the Workers Compensation Board will accept responsibility for the full injurious result of the compensable injury.

The Policy gives the following definitions:

Aggravation: The temporary clinical effect of a compensable injury on a pre-existing condition such that the pre-existing condition will eventually return to its pre-accident state unaffected by the compensable injury.

Enhancement: When a compensable injury permanently adversely affects a pre-existing condition.

Worker’s Position:

The worker was represented by his union representative, who made a presentation on his behalf. The worker’s position was that he performed a variety of job related duties which caused increased pressure on his median nerve, which pressure either caused him to develop bilateral carpal tunnel syndrome (“CTS”) or, in the alternative, enhanced a pre-existing CTS.

The worker reported that he began to notice his symptoms sometime in late 2013. He initially experienced numbness in his hands which spread to his fingers. He subsequently began to experience swelling and burning in both hands which became progressively worse and eventually caused him to seek emergency medical assistance. He was diagnosed with CTS. He attributes the development of CTS to the use of power tools at work, exposure to vibration while operating a grader and repetitive lever manipulation while operating the grader.

The worker relied on the reports of an independent ergonomist as well as the worker’s plastic surgeon, both of whom supported the conclusion that a causal link existed between the worker’s job duties and the development of CTS. It was submitted that recurrent exposure to aggravating factors can result in the progression of CTS. In this particular case, the vibration endured by the worker while operating a grader was prolonged. While the intensity from the grader controls may not have been strong, it was coupled with exposure to intense vibration from impact tools and gas-powered trimmers, among others. The worker also noted that he was required to hold his wrists in awkward positions and to undertake movements which likely caused irritation of his wrist tendons and eventually compression of his medial nerve. There was no evidence that the worker had any of the non-occupational risk factors normally associated with the development of CTS.

The worker therefore submitted that the evidence supported the conclusion that his bilateral CTS was either caused by or made worse by the physical demands of his employment and, consequently, his claim should be accepted.

Employer’s Position:

The employer was represented by a workers compensation coordinator who submitted that the worker’s job duties neither caused the worker’s bilateral CTS, nor aggravated or enhanced a pre-existing condition. As such, the Review Office decision should be upheld.

The employer’s representative submitted that the evidence of both the ergonomist and the worker’s plastic surgeon was not persuasive. The evidence from the ergonomist was couched in general terms and was not specific to this particular situation. There was no indication that the ergonomist had reviewed or attempted to specifically test the degree of force or gripping associated with the worker’s job duties, including the operation of the grader. The surgeon, in turn, acknowledged not knowing what the physical demands of the worker’s job included. Without knowing the degree to which the worker had to grip the levers on the grader or the amount of grip strength and vibration involved in the worker’s job duties, there was no way for the surgeon to establish that any specific job duties were responsible for the development of CTS.

The representative also relied on evidence of employees who had previously performed the worker’s duties or who were familiar with the job requirements. They provided evidence that the amount of pressure experienced as well as the amount of force used in operating the grader was not significant. Although the employees did acknowledge repetitive use of levers, it was submitted that repetition alone would not be responsible for CTS symptoms.

The representative therefore submitted that, given all of the evidence, on a balance of probabilities, there was no causal link between the worker's CTS symptoms and his work duties. As such, the appeal should be dismissed.

Analysis:

The issue on appeal is whether the claim is acceptable. For the worker’s appeal to be acceptable, the panel must find, on a balance of probabilities, that the worker’s bilateral CTS arose out of and in the course of his employment. The panel was able to make that finding.

The panel notes that CTS has a number of causes. Some of the most commonly accepted occupational factors associated with CTS include: wrist injury, frequent use of vibrating hand tools, and repetitive or forceful motion with the wrist bent, particularly when done for prolonged periods. Typically, CTS is found in cases where the job duties involve high force or high repetition. Where the CTS is bilateral, it is more often associated with systemic or non-work related factors. It can, however, be found to be related to work where the evidence shows that both hands and wrists were exposed to the types of occupational hazards that could lead to the development of CTS in both hands.

In this case, during the hearing, the panel carefully reviewed with the worker the nature of his employment duties and had him describe his workday. The vast majority of his time was spent operating a grader usually for several hours each day and some days for as many as 12 hours at a time along long stretches of rural roads. The operation of the grader involved a constant exposure to vibration in both hands as well as regular repetitive manipulation of the grader levers by both hands. Vibration levels were frequently exacerbated by hitting rocks and uneven ground. In addition to the grader operation, the worker also performed regular maintenance of the grader and equipment, which frequently involved repetitive hand movements and awkward hand positioning, as well as the operation of power tools, trimmers and other devices which generated vibration.

After considering the evidence before us, the panel is satisfied that on a balance of probabilities, the mechanism of injury is consistent with the development of CTS. The majority of the job duties in operating and maintaining the grader involved persistent vibration at a frequency that would result in CTS symptoms. Other job duties were also contributory to the development of CTS.

The panel therefore finds that the worker’s claim is acceptable. The worker’s appeal is therefore allowed.

Panel Members

K. Wittman, Presiding Officer
A. Finkel, Commissioner
M. Kernaghan, Commissioner

Recording Secretary, J. Lee

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

Signed at Winnipeg this 27th day of April, 2018