Decision #113/99 - Type: Workers Compensation


An Appeal Panel hearing was held on July 6, 1999, at the request of a union representative, acting on behalf of the claimant. The Panel discussed this appeal on July 6, 1999.


Whether or not the claimant is entitled to further wage loss benefits and medical service after February 6, 1998, in respect to her work-related injury of April 1, 1997.


That the claimant is entitled to further wage loss benefits and medical service after February 6, 1998, in respect to her work-related injury of April 1, 1997.


On September 16, 1997, the claimant, a long-term laundry attendant, filed a claim for workers compensation benefits. The worker reported that "the pain started off slowly, but it progressed to a point now that I can barely move my arms when I finish my day".

Initial medical reports described diminished strength and function involving both wrists and hands. The initial diagnosis was reported as possible tendonitis or questionable carpal tunnel syndrome. Nerve conduction studies performed on October 1, 1997, did not show evidence of carpal tunnel syndrome either side. A conservative treatment program including splints and physiotherapy was prescribed. On November 4, 1997, the Workers Compensation Board (WCB) accepted financial responsibility for the claim. The claimant then received payment of wage loss benefits retroactive to October 16, 1997.

In December 1997, a graduated return to work program was initiated. This program arranged for the claimant to return to work on a graduated basis commencing the week of December 29, 1997, with an anticipated resumption of full duties on February 9, 1998. By letter, dated January 28, 1998, the WCB advised the claimant that she would continue to receive wage loss benefits, up to February 6, 1998, inclusive and final.

A physical medicine and rehabilitation specialist, in a report of January 27, 1998, noted complaints of bilateral hand, neck pain, weakness, headaches and shoulder pain. The impression was a repetitive strain syndrome complicated by mechanical and myofascial pain syndrome of the neck and shoulder girdle muscles. Treatment was initiated.

In a subsequent report, dated February 7, 1998, from the physical medicine and rehabilitation specialist, x-rays received showed evidence of bilateral cervical ribs. He indicated significant improvement in the neck and shoulder pain and that the claimant was able to continue her full time work. The report also noted that the claimant had thoracic outlet syndrome due to cervical rib clinically on the right side.

In a report, dated February 16, 1998, a thoracic surgeon reported complaints of pain in both wrists, with progression to the arms and shoulders, as well as occipital headaches. The surgeon believed that the worker suffered from thoracic outlet syndrome. Removal of the cervical ribs was suggested and surgery was planned for March 9, 1998.

On March 9, 1998, surgery was performed. The file was discussed with the physical medicine and rehab consultant to the WCB who indicated there was no significant objective evidence of a thoracic outlet syndrome present, in relation to the cervical ribs on either side. There was no supporting evidence that the claimant's job duties or physical demands would result in symptoms to the cervical ribs which were present since birth.

On May 27, 1998, an adjudicator advised the worker that wage loss benefits would not be paid after February 6, 1998. The adjudicator stated that following a complete review of file, including consultation with the healthcare department, the WCB was unable to relate the recent surgery to the job duties.

On September 8, 1999, based on a request and submission received from the worker's union representative, the case was referred to Review Office. The submission contended that the claimant's symptoms and disablement subsequent to February 6th should have prompted ongoing benefits, because

  • She continued to suffer the effects of the repetitive strain syndrome, complicated by myofascial pain; and
  • Her pre-existing condition (i.e. cervical ribs) had been enhanced by work-related activities, and resulted in thoracic outlet syndrome.

On October 30, 1998, the case was considered by the Review Office. Following review of file documentation, the Review Office advised that payment of benefits up to February 6, 1998 had been appropriate to address the results of the claimant’s compensable injury (myofascial pain syndrome). The claimant’s injury, diagnosed as thoracic outlet syndrome, did not (on a balance of probability) result from an accident or increased risk which arose out of and in the course of her employment and further benefits and/or medical service (after February 6, 1998) were not payable for the consequences of this thoracic outlet syndrome.

Review Office did not consider there had been significant evidence (historical or medical) to indicate that the claimant’s job activities, or any accident arising out of and in the course of employment, had contributed materially or dominantly to the cause of the thoracic outlet injury. Review Office was satisfied that the worker’s thoracic outlet syndrome was more likely than not an inevitable result of her pre-existent cervical ribs, and would have occurred regardless of speculative risks attributed to her employment activity. Review Office decided that the worker was not entitled to benefits under the Act for the thoracic outlet injury and its subsequent effects.

A union representative appealed the Review Office decision and a hearing took place on July 6, 1999. The union representative contended that the worker was entitled to further wage loss benefits and medical service after February 6, 1998, in respect of her work-related injury of April 1, 1997.


The claimant's bilateral symptoms have been attributed to a thoracic outlet syndrome by two of her treating physicians. The orthopaedic consultant to the WCB acknowledged that "the claimant's initial symptoms could have been due to a thoracic outlet syndrome." This condition refers to compression of the neurovascular structures in the region between the anterior and middle scalene muscles and the first rib. According to an article on the subject authored by Novak and Mackinnon, "Thoracic outlet syndrome ... is now commonly used to describe patients with symptoms attributed to compression of the brachial plexus and subclavian vein and artery in the region correctly termed the thoracic inlet." The authors caution, however, that "this syndrome remains extremely controversial with respect to its existence, diagnosis, conservative management, and surgical treatment."

The Review Office of the WCB determined that the claimant was not entitled to benefits for her thoracic outlet injury and its subsequent effects. In the opinion of the Review Office the claimant's job activities had not "contributed materially or dominantly to the cause of this thoracic outlet injury." The Review Office relied heavily on the opinion expressed by the WCB's orthopaedic consultant that the claimant did not appear to have an occupation which would lead to or influence the development of a thoracic outlet syndrome.

The claimant underwent surgery for her symptomatic right and left thoracic outlet syndrome. The surgeries were carried out by the Head of thoracic surgery at the Health Sciences Centre. Both of his post-operative reports confirmed the initial diagnosis of thoracic outlet syndrome. The claimant testified that she could feel the improvement in her condition following the surgeries. We accept the opinion of the treating physician contained in a letter, dated August 24th, 1998, that "While there can be no doubt that the anatomy is a congenital finding, the repetitive and cumulative nature of [the claimant's] work directly contributed in a causal way to the compensable injury."

In arriving at our decision, we attached considerable weight to the conclusions reached by Novak and Mackinnon in their previously referenced article, which states:

"TOS [thoracic outlet syndrome] remains controversial and complicated by work-related issues. The concepts of cumulative trauma disorders or repetitive strain injuries are not, in and of themselves, a diagnosis, but rather a mechanism of injury and would be better classified as cumulative and repetitive with specific diagnoses based on the musculoskeletal and neural structures involved. The relationship of this to work must be put into context within the life experience. We believe TOS is a true entity of brachial plexus nerve compression and muscle imbalance in the cervicoscapular region. The causes are multifactorial, however, including poor posture, obesity, abnormal sleeping postures and systemic diseases that may aggravate symptoms, as well as jobs that require excessive repetitive or overhead extremity use. Management of patients with TOS should be directed toward altering factors that aggravate symptomatology. Modification of the workstation, rotation of activities, and weight loss should be considered, but it may not be possible to address postural abnormalities and muscle imbalance without correct physical therapy. Surgery should be considered in those few patients with significant continued symptoms who are unable to relieve symptoms with conservative management."

We find, in accordance with the weight of evidence, that the claimant's thoracic outlet syndrome is, on a balance of probabilities, causally related to the compensable injury. It should be noted that the employer subsequently modified the claimant's work site by increasing the height of her folding table. In addition, the claimant has been working full time at her pre-accident duties since January 18th, 1999, without any further problems or difficulties. We further find that the claimant is entitled to wage loss benefits and medical services after February 6th, 1998. Therefore, the claimant's appeal is hereby accepted.

Panel Members

R. W. MacNeil, Presiding Officer
A. Finkel, Commissioner
B. Leake, Commissioner

Recording Secretary, B. Miller

R. W. MacNeil - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 5th day of August, 1999