Decision #75/06 - Type: Workers Compensation
Preamble
An Appeal Panel hearing was held on April 20, 2006, at the request of the union representative, acting on behalf of the worker. The Panel discussed this appeal on the same day.
Issue
Whether or not the claim is acceptable.
Decision
That the claim is acceptable.
Background
On November 17, 2003, the worker contacted the Workers Compensation Board (WCB) to report an injury involving both her hands. The symptoms of that injury had become obvious to her on August 20, 2003. The worker did not report the injury to her employer until November 2003, because she was waiting to find out a diagnosis. The worker also delayed in seeking medical treatment as initially her symptoms were not that severe.
In a letter dated November 21, 2003, the worker’s doctor diagnosed the worker with bilateral carpal tunnel syndrome, moderate in the right and mild in the left.
On January 9, 2004, the adjudicator spoke with the worker to find out details of the injury. The worker noted that she feels that driving the school bus for the last 24 years attributed to her injury. It was stated that the worker has both hands on the wheel for 95% of the time; the other 5% of the time she is shifting with her right hand. This year most of her driving was urban which required a lot more shifting.
In a decision letter dated January 28, 2004, primary adjudication advised that the WCB was unable to accept responsibility for the worker’s hand injury. It was stated that the worker’s job duties as she described, would not have resulted in bilateral CTS because “although gripping is required for steering, this would not be considered highly forceful and any vibration involved in steering the vehicle would not be considered significant for the development of this condition”.
On February 17, 2004, the worker appealed this decision and her file was sent to Review Office.
In a decision letter dated May 21, 2004, Review Office determined that the claim was not acceptable. They stated that “the duties described by the worker, would not be considered highly forceful. With regard to exposure to vibration, we would be looking for significant vibration, involving duties similar to the use of drilling tools. Vibration from a steering wheel while driving would not be considered causal for the development of a CTS condition”.
In a letter dated December 28, 2004, the worker’s doctor stated that “the worker suffers from bilateral carpal tunnel syndrome, which I believe is a result of her occupation as a school bus driver”.
On May 24, 2005, a specialist sent a letter stating that “this patient suffers from bilateral carpal tunnel syndrome and her work as a bus driver may vary well be related to her carpel tunnel syndrome”.
On June 27, 2005, the worker’s union representative appealed Review Office’s decision and an oral hearing was convened before an appeal panel on April 20, 2006.
Reasons
Chairperson Walsh and Commissioner Leake:
The hearing of this appeal took place on April 20, 2006. The worker attended in person and was accompanied by a representative. The representative made an oral submission and led evidence from the worker herself.
The employer was represented by its Transportation Manager who also made a brief oral submission. Both parties responded to various questions from the Panel members throughout the course of the hearing.
The Panel heard evidence that the worker has been employed as a school bus driver for approximately 27 years. The worker testified that from 1988 on she was employed as a full time bus driver. This involved working an eight hour day which consisted of constantly picking up and dropping off students. The worker testified that during the course of one single day she would shift the gears on her bus at least 500 times.
On a normal route, she said, she would probably make 30 stops in the morning, 30 stops at night plus at least another 30 stops picking up students at schools midday. For each of those stops she was required to shift gears. She was also required to be constantly opening and closing the door. She testified she would have used the door opener 100 times a day.
Regarding the bus doors, she said some of them were very heavy and would be resistant to movement. To open the door she had to press down on a flat piece on the slip handle. She said that she grabbed the handle quite tightly. She also said that she held the steering wheel quite tightly.
The worker testified that her left hand would be on the steering wheel at all times except for when she operated the turning signal which was on the left hand side of the steering wheel and the four-way switches. She said she also activated the lights by using her left hand and thumb. These were overhead lights for stopping. Her right hand only left the steering wheel to change gears. Both hands, therefore, grasped the steering wheel 95% of the time.
She testified there was a great deal of vibration on the steering wheel. The stick shift that she used to shift gears also vibrated quite a bit. It was often very difficult to get into second gear when stopped on some buses. She said sometimes she would have to hit the gear shift with her hand hard, maybe two or three times, in order to shift properly.
Her evidence was that school buses are very different from city buses. They are parked outside in the winter so that the day starts with a cold stiff bus. The suspension on school buses is different than on city buses. City buses, for example, have air suspension whereas school buses have a solid spring suspension. That makes for a bumpier ride.
Further, on city buses the engine is located at the back of the bus while on school buses it is at the front. In fact on a school bus the driver sits with her feet immediately behind where the engine is and is subject to quite a bit of vibration. The transmission on school buses is a standard transmission and is also located just under the feet of the driver so that again there is a great deal of vibration both where the driver is sitting and up the stick shift.
With respect to her symptoms, the worker described experiencing a numbness in her fingers for many years which grew steadily worse. Although it was bad she never attributed it to carpal tunnel syndrome. She first experienced symptoms in her right hand and then later in her left hand. Because she is right handed she said she was more bothered by the pain in that hand. It had been getting steadily numb for at least 10 years up to the time that she was diagnosed with carpal tunnel syndrome. The symptoms in the left hand started about 5 years before that diagnosis.
She described waking up in the middle of the night and finding that her hand was numb. As soon as she would start to do anything during the day where she was holding something she would also experience the numbness. During the course of the day the numbness would come and go. Every day was pretty much the same but on August 20, 2003 the pain was so bad she thought she was having a heart attack. Pain went up her arms and her hands felt like they were on fire. She went to the hospital where, after tests were performed, she was told she had carpal tunnel syndrome.
The worker was referred to a plastic surgeon and underwent carpal tunnel surgery on her right hand on November 16, 2004. The surgeon who performed the operation wrote about the worker in a medical report dated May 24, 2005 saying that "… it is very likely that her occupation has contributed to her carpal tunnel symptoms as she is holding the steering wheel while working and also operating controls on the bus. In summary, this patient has bilateral carpal tunnel syndrome and her work as a bus driver may very well be related to her carpal tunnel syndrome."
In a medical report dated December 28, 2004 the worker's physician certified that the worker suffered from bilateral carpal tunnel syndrome which the physician believed was as a result of the worker’s occupation as a school bus driver. The physician referred to the fact that the worker's job entailed holding a steering wheel all day, repetitively shifting gears and opening and closing the school bus door.
At the hearing of this appeal the worker's representative gave a detailed submission identifying that in his opinion the Board had been too dismissive of links that exist between school bus drivers and carpal tunnel syndrome. The representative admitted that there is not what he called conclusive proof demonstrating a link between school bus drivers and carpal tunnel syndrome but there is a developing body of research and evidence which does establish such a link. The representative brought forward a number of studies which show there is growing evidence demonstrating a link between vehicle drivers and an increased risk for developing carpal tunnel syndrome. He submitted that this awareness will probably lead to more research in the future.
Among the research which the worker's representative did provide was a study from the California Department of Health which has a program called The Occupational Health Evaluation in which physicians report to their Department of Health about conditions they believe to be occupationally related. The evidence in that study showed that 3% of all occupational carpal tunnel syndrome cases involved steering and driving and identified local passenger transportation as one of the higher risk industries in California for carpal tunnel syndrome.
Next, the representative highlighted a document from the Delaware State Education Association. It was a pamphlet entitled School Bus Drivers at Risk which talked about an increasing number of school bus drivers who were reporting difficulties with their wrists and difficulties with carpal tunnel syndrome. The panel's attention was also directed to a document from the Neurology Channel where the observation was made that bus drivers, taxi drivers and truck drivers are occupations that are at a significant risk for developing carpal tunnel syndrome.
Finally, the worker's representative submitted a document from the Brigham and Women's Hospital which is a hospital affiliated with Harvard Medical School where the research identified that vehicle drivers as a group are at increased risk for developing carpal tunnel syndrome.
In reviewing this evidence submitted on behalf of the worker, we note that the material also identified repetitive activities involving the fingers and contact pressure at the base of the palm as risk factors for developing carpal tunnel syndrome. This is consistent with many of the work related activities described by the worker.
It was the submission of the worker's representative that occupational factors were more likely the cause of the worker's carpal tunnel syndrome than any personal risk factors which the worker might have.
With respect to personal risk factors it was admitted that the worker is a woman who has an underactive thyroid condition and who does drink coffee on occasion.
With respect to her thyroid condition the worker testified that for the last seven years she has been on medication which is checked every six months. She has been advised by her physician that her thyroid condition is under control.
While there was some reference in the worker's medical documentation to her having diabetes the worker testified that in fact she does not have diabetes and therefore that is not a personal risk factor in this case.
With respect to coffee consumption the worker testified that she drinks at least two cups of coffee during the day. With respect to hobbies she said she used to bowl but has not bowled for two years. When she did bowl she would do so once a week. She has never done any needlework. Her computer use is limited.
The worker's representative submitted, therefore, that the worker's personal risk factors were minimal as compared to her occupational risk factors.
The employer's representative supported the worker's claim. He admitted that although the school bus industry is improving there is still a long way to go for prevention of these types of injuries. He did not feel that the worker's evidence was in any way an exaggeration of her job requirements.
The worker's representative concluded by submitting that the Board in its previous decision had erred when weighing the evidence and had failed to place sufficient significance on the worker's occupational risk factors for developing carpal tunnel syndrome.
Analysis
Based on the totality of the evidence including the fact that for 24 years each day the worker: traveled 160 kms while driving the school bus; kept her hands on a large vibrating steering wheel for 95% of the time; shifted an often stiff and vibrating stick shift 500 times; and opened doors which often offered resistance, 100 times, we are of the opinion that the worker's bilateral carpal tunnel syndrome did arise out of and in the course of her job requirements.
Section 4(1) of The Workers Compensation Act provides:
Compensation payable out of accident fund
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.
"Accident" is defined in the Act as being:
“a chance event occasioned by a physical or natural cause; and includes
(a) 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
(c) an occupational disease,
and as a result of which a worker is injured.”
Based on the foregoing reasons, we find, therefore, on a balance of probabilities that the worker did experience personal injury by accident arising out of and in the course of her employment.
Accordingly the worker's claim is acceptable.
Panel Members
S. Walsh, Presiding Officer
A. Finkel, Commissioner
W. Leake, Commissioner
Recording Secretary, B. Miller
S. Walsh - Presiding Officer
(on behalf of the panel)
Signed at Winnipeg this 8th day of June, 2006
Commissioner's Dissent
Commissioner Finkel’s dissent:
The worker has applied to the WCB for benefits, relating the onset of her bilateral carpal tunnel syndrome (CTS) condition to her job as a school bus driver. Her claim was denied, and she has appealed that decision 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 WCB, 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 her bilateral CTS condition is 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 worker’s job duties would not have resulted in the development of a bilateral carpal tunnel syndrome.
Evidence and argument:
The worker’s evidence was that prior to her filing her claim in November 2003, she had been driving a school bus in an urban/residential area for 24 years. Her shifts were 8 hours per day, and involved a series of pickups of students from pre-determined residential locations and deliveries of students to schools. As well, there was a series of between-school deliveries during the day, before students were returned to their residential areas at the end of the day. There were approximately 100 stops during the day, as well as stops for stop signs and traffic lights.
The streets were all concrete and asphalt, and there was no highway driving or high speed zones on her route. The roads were in good repair, and there were no concerns about potholes or significant vibration caused by road conditions.
The worker attributed the onset of her bilateral CTS condition to how she drove the bus. She asserts that certain job duties were causative of her CTS condition. She relates her right hand symptoms to her constant use of a stick shift and to the use of a handle to open and close the school door, up to 100 times per day. Her left hand was only used to operate an emergency brake and turn signals, and to activate the overhead lights. The bus had power steering, and she regularly drove with her hands gripped in a 10 o’clock and 2 o’clock position.
As to her CTS symptoms, the worker advised that her symptoms first appeared a few years earlier, more or less simultaneously, with right symptoms greater than left. She worked only during the school year, and thus had stopped work at the end of June 2003. She was not working in July and August 2003. On August 19, 2003, she awoke in the middle of the night with extremely sore hands, which was later diagnosed as being CTS.
In support of the causal relationship between the worker’s job duties and the development of CTS, the worker’s representative provided literature from the California Dept of Health indicating that 3% of all instances of occupational CTS in California involve driving and steering. The same study notes that “local passenger transportation had a 104/100,000 rate of CTS incidence.” He also cited a Delaware State Education document noting that “there are also reports of hand/wrist injuries like carpal tunnel syndrome” for bus drivers.
Analysis
CTS is a unique medical condition that can arise from work-related activities, and also from non-work related factors. Medical literature points to such factors as age (40s and up), gender (female), body mass index, diabetes, and hypothyroidism amongst others, as factors leading to the development of CTS in the general population. Many CTS cases are idiopathic in origin (that is, they have no known cause), with some literature suggesting that up to 50% may fall into this category.
Where work duties are suggested to be the source of the problem, there is considerable medical literature focusing on the specific types and frequencies of body mechanics that could lead to the development of CTS. It does not simply arise out of general physical work. The factors most commonly cited as leading to the development of CTS are high force/high repetition activities involving the hands or activities involved with awkward bending of the wrist or forceful pinching and gripping, or direct pressure on the carpal tunnel area of the palm or wrist. Of decreasing causal significance are high force/low repetition activities of the hands, followed by low force/high repetition activities.
It is clear from the medical literature that CTS cases are considered to be “acute” events with an accumulation of micro-traumas over time. This is in contrast to an occupational disease where claims may be established by demonstrating significant increases in the prevalence of a particular disease in a specific workforce in a specific industry in comparison to a general population. As such, it is critical that the analysis of CTS claims be made on a case-by-case basis: what were the specific job duties and how did the worker perform them? Did they have the occupational hazards typically associated with the development of CTS?
In this context, the studies presented by the worker’s representative have little value. Epidemiological studies are more appropriately considered in claims involving occupational disease, but have no value in dealing with a specific event-type claim. Stated differently, a broad conclusion that 104/100,000 people in local passenger transportation have been diagnosed with CTS, does not break down the types of vehicles or steering systems or road conditions, or bilateral versus right CTS conditions, or provide insight on whether there were other factors involved (for example, we do not know whether CTS was caused by those duties or was there an aggravation of a pre-existing condition, were other contributing factors – body mass index, diabetes, age, gender, hyperthyroidism – also in play? Were these based on accepted worker’s compensation claims or on reports from disability insurers?). As such, these external sources, while interesting regarding an occupational trend, have no impact in the decision as to whether this particular worker’s CTS condition specifically arose out of her specific job duties.
Dealing with the worker’s job duties, I found that they are not causative of her bilateral CTS condition. The simultaneous onset of a bilateral CTS condition (when it first arose a number of years ago and when it flared up bilaterally on August 19, 2003) is not a common phenomenon arising out of work place duties. It is strongly suggestive of a systemic non-work-related source, but it can nonetheless arise from work, if 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 each hand.
My review of the evidence does not find this to be the case. In particular, the worker’s evidence is that her dominant job duty for the left hand was to steer the bus. Her left hand was used in an ergonomically correct position on the steering wheel while driving. The bus had power steering, the route was urban/residential with low speeds, and there were many stops on the routes which would have allowed for short rest breaks. The condition of the roads was not a factor. The only other job duties for the left hand involved the use of turn signals, the emergency brake and overhead light, which the worker indicated were inconsequential activities.
Given this evidence, I do not see, within the left hand job duties, the types of CTS occupational hazards that I noted earlier. As the left and right hand conditions arose simultaneously, I conclude that the onset of the worker’s bilateral CTS symptoms several years ago was not as a result of her job duties. I further note that the worker did not report any change in her symptoms in the months preceding the end of the school year in June 2003, and had not worked for approximately seven weeks before her acute flare-up of symptoms on August 19, 2003. This strongly suggests that this aggravation or flare-up was also not related to her job duties in June 2003 or earlier.
Although it is not necessary to establish an alternative source for the worker’s medical condition, I would again note that the simultaneous development of a bilateral CTS condition strongly suggests a non-compensable, non-work-related source. There are also a number of other general factors leading to CTS as noted above, that are present in this case, in particular age, gender and a thyroid condition.
Conclusion:
Based on this analysis, I find, on a balance of probabilities, that the worker’s job duties were not causative of her development of bilateral carpal tunnel syndrome. Accordingly, I would deny the worker’s appeal.
A. Finkel, Commissioner
Signed at Winnipeg, this 6th day of June, 2006.