The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker filed a claim with the Workers Compensation Board ("WCB") for numbness and pain in her right hand/arm that she related to her employment activities as a cleaner. The claim for compensation was denied by primary adjudication and Review Office as both were unable to establish that the worker's right arm condition was caused by the nature of her job duties. The worker disagreed with the decision and an appeal was filed with the Appeal Commission. A hearing was held on February 3, 2011 to consider the matter.

Issue

Whether or not the claim is acceptable.

Decision

That the claim is not acceptable.

Decision: Unanimous

Background

The worker filed a claim with the WCB for numbness in the fingertips of her right hand which she related to her job duties that involved sweeping and mopping. She began to experience the symptoms on or about August 28, 2009. The worker indicated that as time went on, the pain spread to her right wrist and arm and up into her shoulder. From September 14 to 22, 2009, she shared her concerns with several co-workers. The worker noted that a large number of her required duties either started or aggravated her symptoms. These included opening garbage bags, pouring disinfectant into a pail, unplugging or plugging in the auto-scrubber, sweeping, opening doors, and lifting various items - anything that involved the use of her fingers.

Information obtained from the employer confirmed that the worker began to experience pain and a numbing sensation in her right hand/wrist on or about August 28, 2009. The employer provided the WCB with a job description that outlined the duties performed by the worker during the course of her employment as a cleaner. The employer noted that although the worker used both hands and arms performing her work duties, there was a variety of duties and flexibility that existed whereby the worker would not have to do a particular job for any prolonged or sustained periods of time during a regular 8 hour shift. There was also a sufficient range of heavy to light type duties such that no staff member would have to compromise their physical well being by performing repetitive heavy work putting undue and prolonged stress on any single part of their anatomy.

A doctor's first report dated September 23, 2009 noted that the worker had pain in the right arm and hand. The worker was mopping and sweeping and had nocturnal pain. There were positive Tinel's and Phalen's signs.

On October 2, 2009, the treating physician noted that the worker had a pinched nerve and carpal tunnel syndrome.

Primary adjudication gathered information from the employer and the worker in regard to the worker's job duties, work history and the onset of her right hand symptoms. File records showed that the worker had been employed as a cleaner with the employer since December 2005. On July 6, 2009, the worker started a new assignment which included the cleaning of a daycare area. She worked until July 10, 2009 and took vacation until August 4, 2009.

In a December 2, 2009 report, the treating physician noted that the worker was complaining of numbness of the right hand and thumb on November 4, 2009. There was some paresthesias and some nocturnal discomfort. The worker described a retrograde pain up into the right arm and forearm. The worker had involvement of both the right and left hand but the right hand seemed to be the dominant. Nerve conduction studies (NCS) were arranged.

An NCS report dated November 17, 2009 stated the following: "…the nerve conduction study was suboptimal but it appears the right median motor distal latency is within normal limits but the distal latencies of the right median sensory responses are mildly delayed which suggests right median neuropathy at or distal to the wrist (e.g. CTS). She declined nerve conduction study of the left hand."

In a decision dated December 10, 2009, the worker was advised that her claim for compensation was not acceptable as it was the WCB's opinion that there was no evidence that she was exposed to high force repetitive activity involving motions of the wrist such as twisting, gripping, pulling, pinch pressure or repetitive wrist flexion/extension that would result in the development of carpal tunnel syndrome. It was felt that although the worker's job duties could be considered repetitive in movement, the movements were not considered to be high force repetitive activity and there was enough variety between each job task for there not to be constant repetition in one specific movement for a long period of time.

In late December 2009, the worker provided the WCB with clarification in regards to her job duties and medical information from her attending physician to support that the repetitive high speed force work performed by the worker was responsible for the development of her CTS condition.

On January 6, 2010, a WCB medical advisor was asked to review the new information and to provide an opinion as to whether the worker's job activities led to her CTS condition. In a response dated January 28, 2010, the medical advisor stated:

The July/August duties document was reviewed. All of the activities require wrist flexion/extension and wrist radial/ulnar deviation. These are repetitive motions that are reported as being associated with the development of a carpal tunnel syndrome. Whether or not all of these activities represent high force repetitive activity can not be determined as a good definition of high force as regards the wrist is lacking. On probability scrubbing, cleaning and stripping floors would represent a medium force of repetitive activity. Repetitive activities have been variously defined as activities that are performed at 50% or greater portion of the work day. Other disciplines have defined repetitive motion as motion that exceeds 1000 motions per hour. From the job description it would appear that the identified activities are repetitive.

The tasks identified in the job description are varied but they all involve wrist flexion/extension and wrist ulnar/radial deviation movements. It is therefore the cumulative effect of these activities that may lead to the development of CTS.

It is not clearly known what anatomical changes will predispose to development of CTS. The CTS develops, on probability (sic) that the carpal tunnel has already been narrowed.

On probability [the worker] work related activities contributed to development of the CTS like symptoms, but not to the predisposing anatomical changes.

In a letter dated February 24, 2010, the worker was advised that:

New information you provided to the WCB indicated that you were responsible for applying wax and seal products to floors. The information obtained from you and your employer supports that on average, you may have applied a total of 6 coats of wax and/or seal products during an average shift. Given your estimation that it takes 20 minutes to apply one coat of either wax or seal, and noting the mechanism you described in order to apply the product, it appears the total amount of time spent on this task would be 2 hours of an 8 hours shift. It was noted the task did not have to be completed without interruption; there was opportunity to change to other tasks, as the product required drying or curing time between each coat.

Based on all information obtained from you and the employer, including the number of floors that would have been waxed per shift, the anatomical movement you described as having to perform in order to apply the products, and the estimated duration of time it would take during an 8 hour shift to complete the wax and seal task, it remains the opinion of Rehabilitation and Compensation Services that the amount of time, and movement required to wax the floor would not be considered to be high force repetitive activity.

On March 1, 2010, the worker asked Review Office to reconsider the decisions made to deny her claim. The worker maintained that her summer cleaning duties consisted of high force repetitive activity and was the cause of her CTS condition.

In a decision dated March 25, 2010, Review Office stated that it found no evidence to support that the worker suffered personal injury by accident arising out of and in the course of her employment. It was felt that the worker's work activities such as waxing, sweeping or washing floors did not involve any degree of high force and repetitive activity. Review Office noted that the worker's job as a cleaner did not involve long stretches of any specific activity or duties with significant amounts of mechanical stress or force. The job duties varied substantially and high force and repetitive activity was not evident. The worker disagreed with Review Office's decision and an appeal was filed with the Appeal Commission.

Following the February 3, 2011 hearing and discussion of the case, the appeal panel requested a narrative report from the treating physician and copies of all laboratory investigations. The panel also requested a copy of the worker's claim with a disability insurance carrier in relation to her right arm. The requested information was later received and was forwarded to the interested parties for comment. On April 18, 2011 the panel met further to discuss the case and render its final decision on the issue under appeal.

Reasons

Applicable Legislation:

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:

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. (emphasis added)

The key issue to be determined by the panel deals with causation and whether the worker’s right sided CTS arose out of and in the course of her employment.

Worker’s position

The worker was represented by a worker advisor at the hearing. The position advanced on behalf of the worker was that the evidence supported a causation relationship between the onset of the worker's CTS symptoms and her job duties. It was submitted that her work duties, and especially the seasonal work she performed over the summer, required a great deal of repetitive wrist flexion and extension, with varying degrees of force. As well, some activities, such as applying wax to floors, were performed for prolonged periods of time. The opinions of the treating physician as well as a WCB medical advisor were relied upon as support of a causal relationship.

Employer’s Position

The employer's human resources officer was present at the hearing. It was submitted that sufficient flexibility and variety of duties existed within the worker's job description such that it was not necessary for her to have to compromise her physical well being by performing repetitive heavy work that would place undue or prolonged stress on any specific part of her body, including her wrist. Further, in the worker's case, the symptoms were claimed to have developed within 24 working days of her starting at a new job location. She had worked for only five days before going on three weeks vacation. She returned to work on August 4, 2009, and within 19 working days, she began to experience symptoms of CTS which she solely attributed to work. It was submitted that even if the custodial duties in question were considered to be in the high force and repetitive range, the number of working days would not have been of long enough duration to have caused such severe CTS symptoms. Finally, it was submitted that if the symptoms were in fact caused by work, they would have subsided by the time of the hearing, given that the worker had been absent from work for the past 16 and one half months. It was noted that the worker was receiving private disability benefits, in part for a condition which was unrelated to the matter at hand, and further medical investigations were continuing. It was suggested that the panel may wish to obtain elaboration on the worker's current medical status.

Analysis

To accept the worker’s appeal, we must find on a balance of probabilities that she suffered injury by a workplace accident within the meaning of subsection 4(1) of the Act. In order to do so, we must find that her right sided CTS was causally related to her work duties. On a balance of probabilities, we are not able to make that finding.

CTS is defined as the impairment of the motor and/or sensory function of the median nerve as it traverses through the carpal tunnel. It is caused either by intrinsic swelling of the median nerve or by extrinsic compression of the median nerve by one of the many surrounding structures of the wrist. CTS has a variety of causes. It can be caused by underlying systemic conditions such as rheumatoid arthritis, osteoarthritis, hypothyroidism and diabetes. Middle aged females, individuals with a high body mass index, smokers and people genetically pre-disposed to the development of CTS are also at increased risk for the development of CTS. It can also be caused by some work activities. There remains considerable debate in the medical literature as to what work factors may cause CTS. Occupational factors most commonly accepted to be associated with CTS include a wrist injury, frequent use of vibrating hand tools or any repetitive, forceful motion with the wrist bent, especially when done for prolonged periods without rest. It is generally considered that the greatest frequency of occupationally related CTS is found where the job duties involve high force and high repetition.

To decide this appeal, the panel must carefully examine the worker’s job duties to determine whether, on a balance of probabilities, they might have caused her CTS.

At the hearing, the worker was asked to give a summary of the regular and seasonal duties which she believed resulted in her CTS. The worker indicated that during summer clean-up, she had to do a lot of the cleaning that had been neglected over the year. This involved extensive scrubbing. The worker specifically identified having to do a lot of hard, fast scrubbing of a freezer chest, stove and fridge using detergent and a cloth with her right hand. She also did scrubbing and scraping with her right hand in other areas, including a sink and a shower room.

The other main task identified by the worker was washing long hallway walls, washrooms, change rooms and showers using a broom brush/mop with a long handle. She would dip the head in a pail of water, then use both hands to grasp the handle and splash water on the wall to scrub it. A mop was also used to wax the floors, which was done at a fast pace as the worker wanted to finish as many rooms as possible.

After considering the nature of the work duties performed, the panel is not convinced that the duties the worker performed during the summer of 2009 were causative in the development of the right sided CTS which was detected in the nerve conduction studies of November 17, 2009. In the panel's opinion, the development of this condition was unrelated to her job duties as we are not able to indentify sufficient repetition or loading of the worker's wrists while in a flexed or awkward position which would, in and of itself, tend to cause CTS to develop. There was sufficient flexibility in her job to permit the worker to rest or change motions when required. The panel also acknowledges the employer's evidence that the worker had only been performing the duties for a limited number of days before the first onset of symptoms, with an intervening three week period of vacation. In our opinion, the limited duration of time she performed the motions further supports that the CTS was not caused by the job duties.

Following the hearing, the panel obtained further information regarding the worker's medical status. A second nerve conduction study had been performed on April 22, 2010. The results were considered more reliable than the earlier study as there was less resistance on account of pain. The results from the April 2010 study indicated evidence of bilateral CTS (mildly delayed) with the right wrist symptoms greater than the left side. An MRI performed January 19, 2011 indicated a right paracentral disc protrusion at C5-6 which impinged on the anterior aspect of the cord. The treating physician opined that the worker had a disability related to CTS and indicated that she may also have a cervical radiculopathy which would only amplify and compound the disability, weakness and symptoms related to her condition.

The new medical evidence reveals that the worker's CTS condition has now been diagnosed as a bilateral condition. This information further supports the panel's disinclination to find a causal relationship as a bilateral condition is often considered indicative of a non-work related etiology. The worker's evidence regarding job duties was also that she always used her right hand to perform the repetitive scrubbing work and that the only time she used both hands was to use the mop. In view of this evidence, it is questionable how left sided CTS would develop. If we assume that the left sided CTS is of idiopathic etiology, we are inclined to make the same assumption as pertains to the right side as well.

It is noted that the new medical evidence was not available at the time the WCB medical advisor and the treating physician considered causation, and this reduces the reliance the panel places on their opinions.

In the panel's opinion, the weight of the evidence supports the conclusion that the worker's right sided CTS was not caused by her job duties. We therefore find that her claim is not acceptable. The worker's appeal is dismissed.

Panel Members

L. Choy, Presiding Officer
P. Marsden, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kosc

L. Choy - Presiding Officer

Signed at Winnipeg this 9th day of June, 2011