DECISION NUMBER:

20240030

OBJECTING PARTY:

WORKER

REPRESENTED by:

WORKER REPRENTATIVE

RESPONDENT:

EMPLOYER

REPRESENTED by:

EMPLOYER REPRESENTATIVE

HEARING:

VIDEOCONFERENCE

HEARD by:

DATED:

D. BOWKER, APPEALS RESOLUTION OFFICER

MARCH 19, 2024

ISSUE

The worker objects to the eligibility adjudicator’s September 4, 2012 decision to deny initial entitlement to bilateral wrist carpal tunnel syndrome (CTS).

BACKGROUND

This frame assembler for a window and door manufacturer reported experiencing a gradual onset of symptoms in their bilateral wrists over the course of five or six years they attributed to job duties involving repetitively squeezing clamps onto window frames approximately 800 times per shift and the vibration of the screw gun. The worker was diagnosed with bilateral CTS on August 23, 2012.

The September 4, 2012 decision denied initial entitlement to CTS as the eligibility adjudicator could not establish the medical attention the worker sought on August 23, 2012 was related to the onset of symptoms they experienced over the course of five or six years. The eligibility adjudicator noted the worker continued working their regular job duties and did not report any ongoing symptoms to the employer prior to August 23, 2012.

The worker representative requested a reconsideration of this decision. On July 29, 2022, the eligibility adjudicator upheld the denial of initial entitlement as they could not establish the work duties the worker performed were compatible with the diagnosis of CTS. The eligibility adjudicator noted the majority of the worker’s job duties offered sufficient variation in their postures with the opportunity for rest and recovery between tasks. The eligibility adjudicator further found that, as the worker’s pre-existing paraesthesia and arthritis in their wrists remained unchanged following the CTS release surgery, their wrist symptoms were not due to CTS.

The objection to the denial of initial entitlement to CTS forms the basis of this appeal.

AUTHORITY

Operational Policy Manual

Published

11-01-01 Adjudicative Process

15-02-01 Definition of an Accident

November 3, 2008

October 12, 2004

Workplace Safety and Insurance Act, 1997

Workplace Safety and Insurance Appeals Tribunal Medical Discussion Paper: Carpal Tunnel Syndrome, Dr. Graham, March 2003.

ANALYSIS

I have carefully considered all of the available information, legislation and relevant operational policies in reaching this decision. I find in favour of the worker. My reasons for this follow.

Worker Position

The worker representative submits the diagnosis of CTS is compatible with the work duties as described by the worker. The representative maintains that on the balance of probabilities, the CTS is work-related.

The worker representative submits the worker was approximately 49 years old on the date of accident and had worked for the employer at that time for approximately 11-12 years building window frames. The representative submits the job duties were repetitive and the clamping duties in particular were the most physically demanding part of their job.

The representative notes the job duties as described by the worker required a strong grip with pressure to screw in nails, apply the clamps, caulk, and staple as the frames were built. The worker representative disagrees with the position the worker was always using a neutral body position and notes the job description provided by the employer did not include the necessary squeezing and maneuvering with the hands required to build the frames for each window.

The worker representative submits the July 2012 diagnostic electromyography (EMG) findings indicating bilateral to marked median neuropathy are confirmation of CTS in the worker’s bilateral hands. The representative notes the diagnosis of CTS continued to be echoed in the clinical evidence and the worker’s physician referred them to the Hand and Upper Limb Clinic once their WSIB claim was denied. The representative notes the clinical evidence continued to show bilateral neuropathies in the worker’s wrists with the right wrist greater than the left.

The worker representative notes the worker was assessed by a rheumatologist in November 2015 and the report following that assessment confirmed the worker did not have arthritis. The representative further notes the worker was later diagnosed with underlying osteoarthritis.

The worker representative submits the Workplace Safety and Insurance Appeals Tribunal (WSIAT) medical discussion paper on CTS defines the condition as numbness, tingling, and weakness of the hand caused by compression of the median nerve as it travels through the hand. The representative notes the paper identifies work-related activities that expose an individual to biomechanical strain including vibratory tools, flexion, and extension as risk factors leading to the development of CTS.

The representative notes that while CTS is associated with osteoarthritis, the conditions co-exist but do not cause each other.

The representative submits that given the worker’s reported paraesthesia of the hands, the work duties requiring forceful gripping for clamping and the use of vibratory tools over time, these work activities would induce CTS and were therefore the probable cause of the worker’s CTS.

The worker representative submits the delay in reporting symptoms does not mean there is no entitlement as the date of accident in a gradual onset disability injury is the date of first medical attention noting the latency between the onset of symptoms and the worsening to the point where a worker seeks medical attention.

The representative notes the CTS diagnosis has always been attributed to the work duties and the worker’s report of their work duties has remained consistent throughout the file history. The representative submits this is evidence the worker was also reporting their job duties accurately to their physician.

The worker representative is seeking the overturning of the decision to deny initial entitlement to CTS.

Employer Position

The employer submits the decision to deny entitlement is correct and the worker’s underlying medical condition is the cause of the worker’s CTS

The employer submits the cause of the worker’s CTS was not work-related. The employer notes the worker remains off work at this time and they would expect the worker’s symptoms would have resolved with this layoff.

The employer notes the EMG report of 2012 identified a 10-year history of paraesthesia with marked arthritis but did not indicate a specific diagnosis of CTS. They note that while the August 23, 2012 Health Professional’s Report (Form 8) indicated a diagnosis of CTS, this was not corroborated by the EMG test results.

The employer submits the worker’s regular job duties were more routine than repetitive and notes the eligibility adjudicator also found the job duties were routine rather than repetitive as they did not require repetitive manoeuvres of the wrist.

The employer further submits the employer is a manufacturer of custom window and door processes that do not involve short cycle times or require sustained, awkward postures.

The employer is seeking no change to the original decision to deny initial entitlement to bilateral CTS.

Worker Testimony

The worker testified they were hired by the employer in 1999 and their job duties remained the same throughout their employment.

The worker testified their job duties involved building frames for windows. The worker stated they would begin by cutting wood to the length of the window with a chop saw with a 10-inch blade, cutting 45° angles on the corners. The worker noted the chop saw did vibrate. They would use one hand to hold the wood against the fence and one hand to stabilize the wood.

Following that, the worker testified they would put the corners of the wood together with a caulking gun, using both hands to squeeze the trigger of the caulking gun. They would clamp the corners together, using a hand clamp that was squeezed by their right hand to tighten onto the frame. The worker testified this required 16 clamps in total. Following this, the worker stated they put screws in to secure the window. The worker would turn the window and put a screw into each corner.

The worker testified they used a brick mould around the exterior of wooden windows. The brick mould was made of wood and required cutting to fit around the window. The sill of the window slid into the brick mould. They stated they used a nail gun to nail the brick mould onto the frame. The worker noted they applied caulking at the top to put it together before clamping it so it would not move.

The worker stated a hole was drilled into each top corner and a screw added. They noted the bottom of the sill had holes drilled and nails added to the bottom, usually between every 8 to 10 inches. The worker used a chop saw to cut the brick mould.

The worker testified the brick mould sat against the window frame as it went up against the house. They stated if the brick mould was twisted, it had to be clamped to ensure it did not move so it would be square to the frame. The worker testified the nail gun would “jump” when it was squeezed and would move a ½ inch. They noted they were steadier with their right hand than their left.

The worker stated they had to spin the window on the bench to rotate it. They stated they repositioned the window so it was right in front of them to avoid stretching and reaching as much as possible.

The worker testified they would add a jamb extension and this required flipping the window so the brick mould was facing downward. The worker explained they cut a piece of wood to length and attached it with glue, clamped the piece down and a jamb extension gun/brad nailer was used to attach the jamb extension to the frame. The worker estimated they were required to use the clamp approximately 20 times to attach the jamb.

The worker testified aluminium windows required cutting and the aluminium had to be manipulated in place to be straight and then clamped to ensure it was over the frame. There was no brick mould for aluminium windows but the worker noted they had to use a specific type of adhesive tape and screw the aluminium to ensure it was watertight

The worker testified they built approximately 25-30 windows per day and worked eight hours Monday to Friday and six hours on Saturdays. The worker noted they regularly worked overtime and would often go in an hour early. They estimated they had to perform approximately 10,000 squeezes of the clamps per month.

The worker testified they felt all their job duties contributed to their wrist symptoms. They felt squeezing the clamps repetitively was a particular contributor to their symptoms. They noted the clamp required pressure to squeeze and they were required to use force with both of their hands to apply the clamp.

The worker testified they tried to adjust their work as their symptoms progressed but it was difficult to

self-modify. They noted they would take breaks more frequently. The worker stated there was no specific quota per day but if they completed less than 20 windows per day, the employer would not be happy.

They noted there were many orders to complete and they were able to complete two windows to any other co-worker’s one window as they were fast at building windows.

The worker stated they also used a jamb extension gun (staple gun). They stated this was not heavy but the aluminium stapler “had a little kick to it” as it was a heavier gun requiring a push to it. They noted they mostly stapled with one hand but sometimes would use two.

The worker noted the wood for the windows was in pieces and the weight depended on the size of the window. The worker further noted that as items such as brick mould or aluminium were added to the frame, the weight increased.

The worker stated that once the window was built, it was taken off the bench and either put on the floor or slid across to the next bench to continue being assembled.

The worker testified they first began to feel symptoms in their wrists five or six years after they started working. They noted they began to wake up in the night with numbness in their fingers. The worker stated they went to their doctor, were sent for an EMG and it came back with a diagnosis of CTS.

The worker testified they were given braces to wear at night while they slept to keep their wrists straight. They noted these braces did not help their symptoms. The worker noted their symptoms worsened and they were having difficulty doing their job at work. They would drop the gun as their hands and fingers were numb. They would stop, shake out their hands and fingers and continue on with their work.

The worker testified they would build two to three frames in a 10-minute period. They estimated they used the clamps 450 times per day for the wooden window frames alone and when the brick mould, jamb extension or aluminium windows were being built this was even higher.

The worker noted a typical shift was eight hours with two 15-minute breaks and a half hour lunch. They stated they worked overtime every other Saturday and approximately two to four hours during the week. The worker noted they worked approximately 50 hours per week.

The worker testified they had CTS release surgery in 2018 and stopped working for the employer after their surgeries. The worker testified the surgery healed their CTS. They testified they stopped working for reasons unrelated to their wrist. The worker confirmed they were advised they did not have rheumatoid arthritis but CTS.

The worker testified they were no longer working. They noted they continued to experience symptoms related to arthritis including swelling, inability to close a fist and bent fingers. The worker explained these symptoms differed from the numbness and tingling they experienced in their fingers due to CTS. They stated those symptoms resolved following their CTS release surgeries.

The worker noted they continued working following their diagnosis as they did not receive any financial assistance and they had to continue working to pay their bills. They confirmed they did a period of modified duties in 2012 after they reported their injury before returning to their regular work duties. The worker noted they have a high pain tolerance that allowed them to continue working.

Assessment of the Evidence

When deciding on initial entitlement in a claim for WSIB benefits, policy 11-01-01 Adjudicative Process

states an allowable claim must have the following five points:

• an employer

• a worker

• personal work-related injury

• proof of accident, and

• compatibility of diagnosis to accident or disablement history

It is undisputed there is an employer and a worker in this claim. The issue before me are whether proof of accident can be established and if so, is the worker’s diagnosis of CTS is compatible with their accident history.

WSIB policy 15-02-01 (Definition of an Accident) provides three types of accidents:

• a willful and intentional act, not being the act of the worker,

• a chance event occasioned by a physical or natural cause, and

• a disablement arising out of and in the course of employment.

There are two types of disablements: a condition that emerges gradually over time (also called a disablement gradual onset), and an unexpected result of working duties (also called a disablement unexpected result).

The worker’s accident history is neither a wilful and intentional act nor a chance event. The accident history is that of a disablement as the worker is claiming their bilateral CTS emerged over time due to the physical demands of their regular work duties. Therefore, initial entitlement in this claim turns on the medical compatibility of the diagnosis to the accident history.

Section 13(2) of the Workplace Safety and Insurance Appeals Act states if the accident arises out of the worker’s employment, it is presumed to have occurred in the course of the employment unless the contrary is shown. If it occurs in the course of the worker’s employment, it is presumed to have arisen out of the employment unless the contrary is shown.

Since the worker’s claim is a disablement, they do not have the benefit of this presumption. As the accident is neither a willful and intentional act nor a chance event, while it occurred in the course of employment, it cannot be presumed that it arose out of the employment. Therefore, the onus is on the worker to prove the work-relatedness of the claimed bilateral wrist injuries.

The test for determining causation in WSIB claims is that of a significant or material contribution. A significant or material contributing factor is one of considerable effect or importance. It need not be the sole or even primary contributing factor.

The standard of proof applied is the “balance of probabilities”. A speculative possibility does not meet this standard, which requires a fact or a causal link to be “more probable than not”.

The July 25, 2012 EMG test indicated the worker had a 10-year history of paraesthesia in their fingers bilaterally, initially only at night that had progressed to being fairly constant. There was marked arthritis of the thumbs bilaterally. The EMG studies were abnormal and there was electrophysiological evidence for bilateral marked to moderate median neuropathies at the wrist. Nocturnal splinting, rest and possible flexor retinaculum release were recommended.

According to the Employer’s Report of Injury/Disease (Form 7), the worker reported increased pain in their wrists and hands from their regular job duties on August 22, 2012. The employer stated the worker advised they had seen their physician in February for their wrist injury but did not report this, as they “did

not want to bother anyone”. The worker further advised they had first noticed their pain approximately five years prior.

On August 31, 2012, the worker explained to the eligibility adjudicator they squeezed clamps onto window frames and then screwed the window frames together with a screw gun throughout their eight-hour shift. The worker estimated they squeezed a clamp approximately 800 times per shift.

The employer submitted a physical demands analysis on July 25, 2022 confirming the work tasks were based on a cycle time of eight minutes and 50 seconds, resulting in seven cycles or frames produced per hour as a maximum. The employer noted the physical demands of the frame assembly job included standing, walking, sitting, lifting, carrying, some pushing and pulling and using tools such as clamps and pneumatic screw guns.

The employer’s submission included pictures from a video of an employee completing the job duties. A coloured avatar over the employee’s body applied by their ergonomic software indicated whether their posture was good, not neutral or awkward. The employer explained the purpose of the software was to prevent subjective evaluations of an individual’s body posture.

I note there was one instance in the documentation where a red line was applied to a forearm extension while the employee leaned forward to reach and move the frame on the bench. For the remaining 10 photographs depicting the job duties the worker performed, there were no indications the work involved awkward postures.

The Workplace Safety and Insurance Appeals Tribunal (WSIAT) medical discussion paper Carpal Tunnel Syndrome notes CTS has been associated with work activities that involve extreme positioning of the wrist and high force and /or sustained vibration. The paper indicates these tasks are typically repetitive and the highest prevalence of CTS was noted in workers with high-force, high-repetitive manual movements. Specific threshold limit values or definitions for the number of repetitions, amount of force, or excessive use remain difficult to define.

The paper further states CTS is more likely to be a concurrent issue as opposed to a secondary condition in conjunction with osteoarthritis of the hand or wrist and is rarely a cause-and-effect issue. CTS causes numbness and/or weakness of the hand due to compression of the nerve.

In this case, I am persuaded it is more probable than not that the job duties as described by the worker were a significant contributing factor to the development of bilateral CTS in their wrists. While I acknowledge the employer’s physical demands analysis did not indicate there were sustained or awkward postures, the testimony provided by the worker is compelling.

I found the worker to be a forthright and credible witness who described the job duties they performed in great detail. I am placing more weight in the worker’s description of their job duties rather than the physical demands analysis provided by the employer as the worker’s description was provided during sworn testimony and was based on their direct experience. The employer’s physical demands analysis did not provide a similar level of depth of detail regarding the duration, force and frequency of the hand movements and positions required to assemble window frames.

I note the worker described repetitive and forceful use of their hands, fingers and wrists with exposure to vibration from the tools they were using to assemble windows, leading to repetitive overuse of their hands and wrists. I find it reasonable an individual frequently forcefully and repetitively squeezing clamps, using

tools such as a screw gun, nailer, stapler, and a caulking gun throughout their shift would develop pain in their wrists and hands.

I also note the worker’s testimony regarding the speed they build windows when compared to their co- workers and their regular overtime hours as further evidence the worker regularly engaged in forceful and repetitive postures.

I am further persuaded the EMG findings of bilateral median neuropathies at the wrist are compatible with the job duties as described by the worker. It is my understanding that CTS is caused by entrapment of the median nerve at the wrist and these findings on the EMG are demonstrative of CTS.

I therefore find the worker has initial entitlement to bilateral CTS.

CONCLUSION

The worker’s objection is allowed. I find the worker has initial entitlement to bilateral CTS. This claim is remitted to the operating area to determine the nature and duration of the benefits flowing from this decision.

DATED MARCH 19, 2024

D. Bowker

Appeals Resolution Officer Appeals Services Division