Decision #111/10 - Type: Workers Compensation

Preamble

The worker is appealing a decision made by Review Office of the Workers Compensation Board ("WCB") which determined that her work duties as a shelf stocker did not have a clinical effect on or aggravated her bilateral carpal tunnel syndrome. A hearing was held on October 20, 2010 to consider the matter.

Issue

Whether or not the claim is acceptable.

Decision

That the claim is not acceptable.

Decision: Unanimous

Background

On February 14, 2007, the worker filed a claim with the WCB for pain in both forearms, wrists and hands which she related to her job duties as a night stocker which involved reaching, lifting and carrying heavy boxes of merchandise for seven and a half hours each shift. She stated that she wore gloves when working in the freezer but stopped working in the freezer section because of her hands about 3 or 4 months ago.

The worker reported that she first noticed symptoms around August or September 2006 while lifting heavy boxes at work. She noticed sharp pain in her hands and tingling sensations. She started dropping things and could not pick them up. She started losing feelings in her hands and had a hard time grasping things. Her fingers would swell and ache. She received a prescription from her doctor to wear a wrist brace on her right hand/wrist but this did not help. She would wake up at night from the pain and numbness.

The employer's accident report dated February 12, 2007 indicated that the worker needed carpal tunnel surgery and that there was no specific incident or accident that arose out of and in the course of her employment.

A doctor's progress report dated February 6, 2007 diagnosed the worker with carpal tunnel syndrome ("CTS") of both wrists.

In a decision dated February 16, 2007, the worker was told that the WCB was unable to establish a relationship between the development of her bilateral CTS condition and an accident as defined under subsection 1(1) of The Workers Compensation Act (the "Act"). The case manager indicated that CTS was a condition which can develop from both work related and non-work related factors. It was felt that the job duties performed by the worker did not require high repetition involving full flexion and extension. It was felt that the worker performed a variety of duties throughout the course of her shift.

A report from the treating physician dated March 7, 2007 indicated that the worker developed CTS from chronic repetitive action and activities with her wrists. The only place where the worker was exposed to this kind of activity was at work. "As you know carpal tunnel syndrome is not associated with acute injury or a specific incident that took place. She did not have carpal tunnel syndrome when she started to work in her current work. Her carpal tunnel syndrome is (in my opinion) work related."

On January 11, 2008 a worker advisor argued that there was enough evidence to support that the worker's job duties aggravated the worker's pre-existing or underlying CTS condition. The worker advisor noted that the worker's symptoms increased in February 2007 due to an increase in the volume of work duties performed over the Christmas season starting in November 2006. She stated that it was confirmed by the employer that the worker experienced difficulties with her wrists while in the performance of her work duties. There was also support from the treating physician dated December 20, 2007 that the increase in work duties was a factor in the worker's requirement for CTS surgery. It was also pointed out that the worker made ongoing complaints to four co-workers.

In February and March 2008, the WCB case manager obtained additional information concerning the exact nature of the job duties performed by the worker. The case manager also arranged for a WCB medical advisor to review additional medical information and to provide an opinion as to the diagnosis with respect to the worker's forearms/hands and the causative factors which would lead or contribute to the development of the diagnosis.

On April 16, 2008, the WCB case manager determined that the worker's job duties did not likely cause, aggravate or enhance her CTS condition as her duties were not consistent with those commonly associated with the condition. In making her decision, the case manager considered the following:

  • the worker sought medical attention on June 13, 2006 for right hand difficulties. On October 2, 2006, nerve conduction studies diagnosed the worker with moderate right CTS and the left hand was inconclusive. The worker was then referred for surgery on October 11, 2006 and on February 27, 2007, a right carpal tunnel release was carried out. It was noted that the worker was diagnosed and scheduled for surgery prior to November 2006;

  • with respect to the cause or aggravation of the worker's CTS, the following factors were outlined as being commonly associated with CTS and were also common in an aggravation or enhancement of the condition: "Forceful, repetitive or excessive hand grasping/gripping/pinching, prolonged fixed posture of the wrist, sustained awkward positioning of the wrist, prolonged exposure to vibratory tools or prolonged pressure to the base of the hand/wrist (palm side)".

  • the worker's job duties as described by her employer and confirmed by the worker were: "She places boxes from a pallet in the back of the store into a cart then wheels the cart to the front of the store. Opens box with a knife, takes the food items out of the box. Food items include oil, flour, canned foods. Then uses both hands to stock the shelves. Then pushes cart to back of the store to re-load it."

  • there were non-work related factors that can be associated with this condition: "female gender, age (especially if over the age of 50 years), body mass index greater than 29, diabetes, thyroid disorders, gout and certain arthritic conditions, genetic predispositions, smoking, menopause and skeletal injury".

Subsequent to the case manager's decision, further medical reports were submitted dated October 1, 2008, July 21, 2009 and August 7, 2009, concerning the worker's current difficulties with her right arm. In particular, the October 1, 2008 report from a pain management specialist stated:

  1. It is my medical opinion that [the worker's] activities that can aggravate her carpal tunnel syndrome do in fact include those that she was performing in the work place.
  2. It is my medical opinion on the balance of probabilities that [the worker's] work duties did in fact aggravate her carpal tunnel symptoms. I think that the proximity of the patient's symptoms to her increase in work function is the best evidence for a link. I would also add to this that the experience we have in dealing with other patients with similar work activities who note an exacerbation of their carpal tunnel symptoms.

On September 1, 2009 and September 4, 2009, a WCB case manager determined that the new information did not warrant a change to the decision of February 16, 2007.

On December 14, 2009, the worker advisor appealed the case manager's decision to Review Office. The worker advisor pointed to specific evidence on file to support the opinion that the worker's claim complied with subsection 1(1) of the Act and that the personal injury was an aggravation arising out and in the course of the employment activities.

On January 28, 2010, it was determined by Review Office that the worker's claim was not acceptable. Review Office stated, in part: "…for Review Office to accept the claim, it must consider that on a balance of probabilities, the weight of evidence supports the position that the worker's work activities had at least a temporary clinical effect on her CTS. Review Office is of the opinion that there is no evidence that it did. It also considers that the issue of whether the worker's CTS was enhanced by her work to be moot. If there was no aggravation, there can be no enhancement ("where a compensable injury permanently and adversely affects a pre-existing condition or makes necessary surgery on a pre-existing condition")". On February 9, 2010, the worker advisor appealed Review Office's decision to the Appeal Commission and a hearing was held on October 20, 2010.

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 bilateral 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 worker's performance of her duties placed stressors on her wrists which contributed to the increase in carpal tunnel symptoms, which ultimately necessitated a stoppage of work. The worker had no problems with her hands when she started her employment in December 2004. She first felt the onset of symptoms while she was performing her work duties in 2006 when she had pain in both wrists. From November 2006 to January 2007, there was a change in her work duties and an increase in her symptoms. The worker described this as a busier season and when it became busier, she was lifting more product. In January, 2007, the worker attended for treatment at a hospital emergency department because her hands became too sore and she could not move her fingers. At the hospital, the worker reported her difficulties were related to work. The worker's attending physician provided a report dated March 7, 2007. In this report, the physician supported that a relationship exists between the worker's duties involving chronic repetitive action and activities with her wrists, and the diagnosis of CTS. Further medical support of the relationship was provided by the worker's attending pain management specialist in his report of October 1, 2008. Overall, it was submitted that in this case, the weight of the medical evidence and the temporal connection between an increase in work duties and an increase in symptoms supported, on a balance of probabilities, a relationship between the work duties, which place stressors on the wrists, and the injury of CTS. The worker's claim should therefore be accepted.

At the hearing, the worker gave evidence regarding her duties as a merchandise stocker. She described a fast paced environment where everyone worked hard to get the product out fast. Her hands were in constant motion. The worker would be required to move boxes of product from pallets in the aisles onto a cart which she would then push to the appropriate shelf space. She would then open the boxes with a utility knife and place the product on the shelves. The worker worked primarily in the pantry department, which involved items such as oil, flour and canned goods. She later had an opportunity to move to another aisle in the pantry department, and for the last part of her employment, she stocked candy and cereal. On occasion, she was required to help out in other departments or load boxes and move pallets from the back of the store to the front. A majority of her work, however, involved putting product on shelves. At the hearing, the worker demonstrated her usual hand motion, which involved lifting product out of the box by holding the top with a pinch grip, then moving her hand to the side of the product to place it on the shelves. It was estimated that she typically unloaded from 5 to 7 skids of product per seven hour shift.

Employer’s Position

A representative from the employer participated in the hearing by teleconference. It was submitted that the employer's position was that the worker's CTS which was initially diagnosed in 2006 was not causally connected to her work duties. The job duties identified by the worker were not consistent with the type of duties typically associated with the onset of carpal tunnel or the symptoms. The worker's activities were not repetitive in nature and were of low force. The worker also had a number of non-work related factors associated with the development of CTS, including menopause, smoking, and gender. The accepted factors of forceful and repetitive hand motions, awkward positions, mechanical stress at the base of the palm, vibration, high force and high repetition were not evidenced in the description of the worker's job tasks. It was therefore submitted that the worker's development of CTS was not related to the performance of her job duties. It was also the employer's position that the job duties did not enhance or aggravate her medical condition.

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 bilateral CTS arose out of and in the course of her work duties. Based on the evidence before us, 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 or aggravated her CTS.

After considering the evidence before us, the panel is of the opinion that the worker’s CTS is not causally connected to her work duties. The job duties identified by the worker are not consistent with the type of duties typically associated with the onset of CTS symptoms. For the most part, the worker’s wrists were not required to be in an extended position for any sustained period of time, and there was little requirement for either high force or high repetition. She had to put the product out quickly and efficiently, but she did so one box at a time. After emptying the product from one box, she would knock the box off onto the floor. She estimated that it would take her about five to ten minutes to empty each box. Periodically, she would have to gather the boxes, collapse them, and put them in a grey bin at the end of the aisle. Given the varying duties and ability to self-pace, the panel finds that the worker was not required to do repetitive work for prolonged periods of time without an opportunity to rest. Although the worker was required to constantly use her hands to place the merchandise on shelving, none of the actions involved in her work appeared to be causative of CTS (ie. no awkward positioning, high force, or exposure to vibration).

In her submission, the worker advisor argued that an increase in duties from November 2006 to January 2007 caused the worker's condition to worsen. This is not, however, consistent with the worker's history of first consulting her physician for CTS in June, 2006 and being referred for surgery in October, 2006. The worker had already been referred for surgery prior to the reported increase in job duties. Further, the worker's evidence was that she had switched to the lighter duties of stocking candy and cereal during the latter part of her employment which are lighter items requiring a less forceful grip. In the circumstances, the panel does not accept that there was a correlation between a worsening CTS condition and an increase in duties.

The worker relies on two medical reports from her attending physicians which relate her CTS to repetitive work involving her wrists and hands. The physicians do not, however, engage in any detailed discussion of the actual hand and wrist movements involved in the worker's job duties. The report of the WCB medical advisor gives specific consideration to whether or not the job duties involve any of the activities associated with CTS. In view of the more specific analysis regarding the presence of aggravating activities, the panel places greater weight on the opinion of the WCB medical advisor.

Overall, on a balance of probabilities, the panel is unable to relate the worker’s bilateral CTS symptoms to the work duties which were being performed by her, either as a causative factor or as an aggravation or enhancement. The worker’s appeal is therefore denied.

Panel Members

L. Choy, Presiding Officer
A. Finkel, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kosc

L. Choy - Presiding Officer

Signed at Winnipeg this 30th day of November, 2010

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