WORKPLACE SAFETY AND INSURANCE APPEALS TRIBUNAL DECISION NO. 1579/09

Transcription

1 WORKPLACE SAFETY AND INSURANCE APPEALS TRIBUNAL DECISION NO. 1579/09 BEFORE: T. Carroll: Vice-Chair HEARING: August 11, 2009 at Hamilton Oral Post-hearing activity completed on July 22, 2010 DATE OF DECISION: April 12, 2011 NEUTRAL CITATION: 2011 ONWSIAT 867 DECISION(S) UNDER APPEAL: WSIB Appeals Resolution Officer decision dated February 29, 2008 APPEARANCES: For the worker: Mr. J. Redshaw, I. U. O. E. Local 793 For the employer: Interpreter: Did not participate Not applicable Workplace Safety and Insurance Appeals Tribunal Tribunal d appel de la sécurité professionnelle et de l assurance contre les accidents du travail 505 University Avenue 7 th Floor 505, avenue University, 7 e étage Toronto ON M5G 2P2 Toronto ON M5G 2P2

2 Decision No. 1579/09 REASONS (i) Post hearing activities [1] The Vice-Chair post-hearing determined that he could not reach a final decision without further medical opinion. The Vice-Chair, after reviewing the Case Record materials and considering the worker s testimony, provided a finding of fact, including the worker s medical history, and the finding of fact is contained in Decision No. 1579/09I. [2] The Tribunal s Medical Liaison Office - after obtaining a CT scan dated January 2006, forwarded Decision No. 157/09I and all Case Record materials to Dr. G. J. Lloyd, orthopaedic surgeon, for his medical opinion in regard to the issues in dispute. [3] Dr. Lloyd s medical report is produced later in this decision. (ii) Issues [4] The Vice-Chair has to determine whether the worker s job duties in general as a heavy equipment operator, caused, or significantly contributed in causing, his lumbar spine condition. (iii) Background [5] As noted, the Vice-Chair s findings of facts are contained in Decision No. 1579/09I. [6] The Vice-Chair s findings are summarized below. [7] The worker, (date of birth October 18, 1948) was a heavy equipment operator from The worker s job duties required he operate a number of machines including bulldozers, back hoes, pipe-layers and cranes. [8] The worker s job duties, especially in the early years, required him to operate the equipment over rough and uneven ground in a sitting position. [9] The file information indicates that the worker, from 1979 to 2001, would not work a full year and often only four to six months. The worker would work beyond eight hours per day and often more than five days per week. [10] In August 1989 the worker injured his left hip at work and was diagnosed with trochanteric bursitis of the left hip. Due to the injury, the worker worked in September 1989 and missed work entirely in He returned to his regular work in June The worker was subsequently granted a 3% permanent impairment award that was increased to 8%, after a further medical assessment, in January [11] The worker continued to work until June The worker worked 10 months in He subsequently worked seven days in 1999 and 2 ½ months in The worker worked a few days in June 2001 when he retired.

3 Page: 2 Decision No. 1579/09 [12] In February 2002 Dr. T. Tweedie, family physician, reported the worker continued to have left hip pain and referred him to Dr. V. Chari, a physiatrist, who examined the worker in September and October The worker was referred to Dr. Chari due to chronic hip pain. Dr. Chari ordered a x-ray and CT scan of the worker s lumbar spine. The x-ray showed mild degenerative disc and arthritic change of the lumbar spine. There was no new fracture of dislocation noted. The CT scan showed some acquired spinal stenosis at L3/4 and L4/5. [13] In September 2002 the worker was examined by Dr. P. Hart, the worker s new family physician. The worker reported pain and weakness in his hip and left leg. On examination, there was tenderness in the region of the left greater trochanter. [14] In a report of October 24, 2002, Dr. Chari commented in regard to the worker s chronic hip pain. He noted the results of the x-ray and CT scan. Dr. Chari felt the worker s pain was not referred pain from the back. [15] An MRI of February 2004 showed a mild degree of central stenosis at the L3/4 level which had not changed significantly since the previous CT scan. There was moderate narrowing of the L4/5 neural foramen with suspicion of mild nerve root compression. [16] In September 2004 the worker reported low back pain into both legs, left greater than the right, and neck pain. Dr. Hart diagnosed bilateral trochanteric bursitis and mild central spinal stenosis with left L4/5 nerve root compression. [17] In February 2006 Dr. R. Dunlop, orthopaedic surgeon, examined the worker. The worker s initial complaints were in the back and legs, predominately the left leg. The worker also complained of trouble with his shoulders, hands, low back, hips and legs. [18] Dr. Dunlop examined the MRI and the January 2006 CT scan. He noted that the CT scan showed multi-factorial spinal stenosis at the L3/4 level. The radiologist did not feel there was significant interval worsening of the spinal stenosis at the L3/4 level in comparison to the previous CT scan of September [19] Dr. Dunlop noted that the worker had diffuse symptoms not particularly related to a L3 root impingement although he felt it may contribute to the worker s problems to some extent. [20] Dr. Dunlop, noting the thickening of the worker s bursa at the elbows, wrists, hands and fingers, thought a generalized arthritic process could be involved. He recommended conservative care. He felt surgery was unlikely to benefit the worker. (iv) Medical comment and opinion [21] In November 2005 Dr. M. Pyskylwec, a doctor with the Occupational Health Clinics for Ontario Workers Inc. (OHCOW), examined the worker. The worker had complaints everywhere but they were concentrated in his back and hips.

4 Page: 3 Decision No. 1579/09 [22] Dr. Pyskylwec had a history of the worker operating heavy equipment for the past 40 years and the worker s hip injury in The doctor understood that the worker had back pain at the time of his 1989 accident and had back pain ever since. Dr Pyskylwec understood that the worker s pain had regressed over the last several years and said the worker had pain all over including the hips, back, wrists, shoulders, knees and neck. [23] After examining the worker, and noting the CT scan of September 2002 and the MRI of February 2004, Dr. Pyskylwec states, in part: This patient has a number of things going on. You have referred him regarding the work relatedness of his complaints, I think most importantly, he has some sort of chronic trochanteric pain on the left side for which he has received a permanent impairment award. However, beyond this it looks like he has some element of degenerative disc disease particularly of the L4-5 level. He has had chronic back pain for the last 15 years. This would be owing to his job as a heavy equipment operator. The constant vibration in the sitting posture has resulted in degeneration of his lumbar spine. As the MRI suggests and some of the clinical findings suggest, this patient has lumbar pathology and some evidence of a left-side radiculopathy. [24] In a report of April 2008 Dr. Pyskylwec reviewed various studies that involved heavy equipment operators, truckers and the and the relationship of these occupations to conditions of the lumbar spine. Dr. Pyskylwec states, in part: Thus, review of the literature implicates whole body vibration in driving as being associated with low back disorders. It remains that this patient worked as a heavy equipment operator for 40 years. A very significant part of his life was operating heavy machinery over rough ground while in a seated posture. He did such work for his entire adult life. It is often difficult to ascertain clear etiologies for medical conditions. I would acknowledge that degenerative disc disease of the lumbar spine may occur as part of the natural aging process. However it is also known that biomechanical risk factors may account for the development of this condition. ( ) In summary, I would reassert my original position that his occupation as a heavy equipment operator was a significant contributing factor to his degenerative disc disease. Many decades of wear and tear on the lumbar spine have likely caused this disorder. It is biologically reasonable that the driving test profession may contribute to lumbar degeneration. The literature supports such an association as evidenced by a number of systematic reviews. [25] Dr. Pyskylwec repeated his position in a report of July 9, He relied on the worker s work history of decades of heavy equipment operation along with the body of literature that associates driving occupations and whole body vibration with low back conditions, as the cause of the worker s degenerative disc disease first noted in Dr. Pyskylwec again noted the difficulty of attributing causation for medical conditions particularly those as common as lumbar degenerative disc disease. However he stated that it was difficult to ignore this patient s significant workplace exposures in assessing the contribution to his degenerative condition of the low back.

5 Page: 4 Decision No. 1579/09 [26] As noted earlier, in 2010, Dr. G. J. Lloyd, orthopaedic surgeon, was provided with the Vice-Chair s finding of fact, the worker s complete file, including a January 2006 scan of the worker s lumbar spine. Dr. Lloyd s medical report is repeated, in part: Background and Understanding of Medical Issues [The worker] is currently aged 62 or thereabouts. There are a number of general medical issues which could be affecting his longevity in the workplace, specifically a reference to cataract surgery in February of 2006 and references to his alcohol intake. As a matter of record, I note that for a lengthy period of time he has had symptoms attributable to trochanteric bursitis. Dr. Brett Dunlop, in a report dated the 14th of February 2006, raised concerns that he had a generalised arthritic process, in addition to the undoubted changes that were present to his lumbar spine. There is clear documentation that he had degenerative disc disease affecting his lumbar spine, particularly at the L3-4 and L4-5 levels, which were causing impingement on the left 3rd lumbar nerve root, together with spinal stenosis. This would add legitimacy to the complaints he was making in February of 2006 to his back (presumably his lumbar spine and his left leg). At that stage then, he would be designated as having (in the context of his lumbar spine) mechanical symptoms, probably nerve root irritation to his left lower limb, and symptoms attributable to cauda equina claudication, although this is uncertain. There clearly was, in all probability, a contributory background in the form of generalised osteoarthritis, given the fact that he was receiving care from a rheumatologist. Also in the documentation, there is reference to him having diabetes mellitus, which was probably contributing to symptoms to his lower limbs, given the fact that (again) Dr. Dunlop in February of 2006 noted an absence of pedal pulses, suggesting that there could be a vascular component to the claudication type symptoms. Review of Literature Provided and Reports I would have concern regarding the report of Dr. Pysklywec dated the 21 st of April 2008, who (in paragraph three) indicates that he had been a heavy equipment operator for forty years with constant exposure. As I review the documentation, this very significantly overstates the longevity of his exposures. There is a document provided by J. Redshaw, Director of Social Services, International Union of Operating Engineers, entitled A Review of the Scientific Evidence. Whist an initial reading gives the impression of being an impressive document supporting the position that there is a causal link between back disorders, driving occupations and whole body vibration, I would have considerable concerns regarding the validity of the conclusions. Whilst an extensive amount of literature was searched, relying on their statement as it relates to text word searches of articles titles and abstracts, no attention appears to have been paid to a review of the incidence of degenerative disc disease and its complications affecting the lumbar spine (and after all this is what we are talking about) in the population at large. This is obviously of considerable importance in making any determination, as degenerative disc disease is known to evolve in the absence of any industrial provocation. There is a very large body of evidence in support of this. I am enclosing two of many potential abstracts in support of this statement. In addition, the analytical methods used in formulating the conclusions do not subscribe to the conventional methodology of meta-analysis, which is the best available standard. I am taking the liberty of appending some information to introduce this concept. The conclusion under the heading of Executive Summary that seems to

6 Page: 5 Decision No. 1579/09 categorically state that, The data support a causal link between back disorders and both driving occupations and whole body vibration should be viewed, at best, equivocal and (for the reasons I have given above) potentially flawed. The reality is that one is dealing with a patient who, in all probability, has generalised inflammatory arthritis, which is a causative factor for the degenerative changes to his lumbar region, who has a condition which is exceedingly common in his age group in patients who are not subjected to vibration. During his working life he has been subject to vibration; however, not for the extended period of time that is referred to in Dr. Pysklywec s report. Response to Questions Posed 1. What is the diagnosis of the worker s present low back problems? He undoubtedly does have degenerative disc disease, together with some of the complications of degenerative disc disease (in the context of the statements I have made above). 2. From the medical reports in the worker s file, and the Vice-Chair s finding of fact and review of the medical reporting and diagnostic testing, is it likely that the worker s job duties operating heavy equipment, that included HPV, caused, or significantly contributed in causing, the worker s diagnosed low back condition? Please explain how you reached your conclusions. This is a very difficult question to categorically answer, for reasons which are apparent above. Subject to these reservations, I think it is improbable that the worker s duties of operating heavy equipment significantly contributed to the evolution of the underlying pathology. 3. If your answer to question 2 is in the negative, is it likely that the worker s job duties as a heavy equipment operator aggravated the worker s diagnosed low back condition such that it accelerated the development of that condition? Please explain how you reached your conclusions. Whilst I think it is improbable that the job duties as a heavy equipment operator aggravated the structural changes or accelerated the structural changes, relying on the patient s subjective commentary, they appear to have aggravated his symptoms. 4. Is (here any other medical information which you feel would be of assistance to (he Vice-Chair and the parties in understanding (he aetiology of the worker s low back condition? The only other information that might add assistance would be to develop a better understanding of the degree to which he has an inflammatory arthritis affecting multiple joints, probably in the hands of the treating rheumatologist. I note your comments regarding examining the patient. I think it is unlikely to change any of the opinions I have expressed. It would simply document his current situation, which is clearly well documented in the material that you provided. I trust these observations are helpful. [27] The Vice-Chair also referred to a Tribunal Discussion Paper entitled Back Pain, by Dr. W. R. Harris, orthopaedic surgeon, and Dr. J. F. R. Fleming, neurosurgeon. [28] Under the heading Aging Change Lumbar Spine the paper states: Aging Change Lumbar Spine Any discussion of back pain is often dominated by the term "Degenerative Disc Disease". This is an inappropriate phrase because what is being described is usually not

7 Page: 6 Decision No. 1579/09 a disease but normal aging change. A better description would be "age related" change. This normal process produces typical x-ray and CT or MR changes which are commonly misinterpreted by physicians as being evidence of something abnormal. In turn this may lead to unnecessary investigation and, sometimes, surgery. With gradual aging, there is loss of water from the nucleus pulposus with resulting thinning of the disc space between the adjacent vertebrae and this can be seen on plain x- rays. The narrowing of the disc space causes the annulus fibrosis to "bulge" and this can be seen on CT or MR scans. It does not usually cause symptoms but if the bulging is excessive one or more nerve roots may be compressed with resultant symptoms. The bulge is centrally located and as there is usually plenty of room in the spinal canal nerve roots are rarely compressed. A lateral bulge, if very large, may sometimes compress a nerve root. This process of bulging is not the result of trauma. Aging is often associated with the formation of a bony out growth (spur, osteophyte, exostosis) at the periphery of the vertebral body. Another result of the height loss is that the facet joints are distorted. This can cause wear and tear changes in them (described as "facet arthritis"). Sometimes the disc narrowing is accompanied by backward ("retrospondylolisthesis") (Fig. 6) or forward (degenerative or pseudo spondylolisthesis) displacement of the upper vertebra on the lower. These tongue twisters simply mean slipping of a vertebra (spondylos=vertebra, listhesis=slip, retro=backwards). (True as opposed to pseudo spondylolisthesis is the result of a bony defect in the structure of the vertebra and will be discussed later {Figs. 7,8}). The incidence of these aging changes is affected by heredity and race. Some families are predisposed to develop marked changes at an early age. Aging change is commoner in Caucasians than in Negroes and Orientals. There is no convincing evidence that these changes which are so obvious on the x-ray or scans cause pain. In most people who have back pain in the presence of aging change, the pain is the result of ligament or muscle strain and not because of the age change seen in the x-ray. There are three conditions in which aging may cause symptoms: 1) a disc problem (herniated, sequestrated, ruptured disc); 2) spinal stenosis (narrowing of the spinal canal); and 3) facet arthritis. ( ) In spinal stenosis (Fig. 11), the gradual formation of bony outgrowths narrows the spinal canal and the openings through which the spinal nerves emerge. This condition is not caused by trauma. In people who have a small diameter spinal canal to begin with, the nerve roots are more vulnerable to compression. This narrowing of the spinal canal produces numbness and weakness ("my legs feel rubbery") in the legs, typically brought on by walking and disappearing slowly with rest. If the symptoms are severe and disabling, surgery to decompress the affected nerve roots may be required. [29] The Vice-Chair also noted the following summary regarding degenerative disc disease found in Decision No. 258/97: Generic information about degenerative disc disease is found in discussion papers and reports prepared for the Tribunal and included in several Tribunal decisions. (See, for example, Decision Nos. 430/89 (November 8, 1989), 324/93 (January 31, 1995), 252/88 (December 13, 1988) and 36/90 (1990) 13, W.C.A.T.R. 325.) Degenerative disc disease occurs in the general population at large and it is generally accepted that it is an aging process in the spine which may be more advanced in some individuals than in others at the same age. Degenerative disc disease is often a progressive idiopathic condition. The process may begin as early as the 20s, with more frequently occurring episodes of pain in the 30s and 40s. It is not fully understood why disc changes occur at an earlier age in some people than in others or why some people experience more back pain from degenerative changes than others. The incidence of

8 Page: 7 Decision No. 1579/09 these degenerative changes is affected by heredity and race. Changes evident on x-rays and scans do not necessarily mean that a person will experience pain. The progressive symptoms of degenerative changes are not necessarily caused by external events such as accidents. There is support in the medical literature both for and against a relationship between degenerative changes in the spine and heavy manual work. [30] The Vice-Chair also considered a 2008 Medical Discussion Paper entitled Osteoarthritis by Dr. M. Tile, orthopaedic surgeon and Professor Emeritus, Department of Surgery, University of Toronto. [31] Dr. Tile states that osteoarthritis rises as one ages. The symptoms usually begin at age 50. He notes that 80% of the population over the age of 50 have x-ray evidence of osteoarthritis in one or more joints. [32] On page 21 of the Paper Dr. Tile answers the question: Does employment in heavy work for many years cause osteoarthritis? [33] In reply, Dr. Tile states that although there is extensive literature on this subject, there is no compelling evidence linking occupations requiring heavy work and arthritis. Dr. Tile completes his answer by stating, Individuals that do heavy work are no more likely to develop OA than those that do sedentary work: however, the heavy work may render the joint more symptomatic, creating the impression that the osteoarthritis is more common in these worker s. (v) The Vice-Chair s analysis [34] The worker is claiming that the operation of heavy equipment [including exposure to whole body vibration (WBV)] caused, or was a significant contributor in causing, the worker s degenerative low back condition (i.e., the worker is claiming an accident in the nature of a disablement). [35] The Vice-Chair considered the worker s claim in the context that the relationship between low back conditions and heavy equipment operators is controversial in the medical/scientific literature. However, the Vice-Chair notes that a number of Tribunal decisions have determined that, based on the individual facts of a case and in the context of the medical/scientific literature, that there can be a causal relationship between occupations as truck drivers, heavy equipment operators and low back conditions. [36] The Vice-Chair notes that each case must be based on its individual facts, and in the context of the accepted medical/scientific understanding that degenerative disc disease (DDD) - osteoarthritis - is common in the general population without exposure to heavy work. Symptoms, together with diagnostic evidence of osteoarthritis, increase with age and usually begin in the 5 th decade. [37] There are two medical opinions that speak directly to this issue. Dr. Pyskylwec finds that the worker s length of time operating heavy equipment, caused, or significantly contributed to the worker s degenerative condition as first demonstrated by diagnostic testing in September Dr. Pyskylwec, to a considerable extent, relied on the findings of a number of studies that link HBV to low back conditions including osteoarthritis.

9 Page: 8 Decision No. 1579/09 [38] Dr. Lloyd on the other hand, questioned the findings of the various studies provided by Dr. Pyskylwec. Dr. Lloyd concluded, based on other studies/literature that DDD is prevalent in the general population and those individuals not exposed to HBV or who operate heavy equipment. He relied on a study that showed 40% of individuals at 30 years of age have degenerative disc disease and 90% of the population have DDD at age 50 to 55. He concluded that the operation of heavy equipment did not cause, or significantly contribute, to the worker s degenerative condition of his low back. He felt the worker s condition was likely as a result of aging. [39] The Vice-Chair, in considering the two medical opinions prefers that of Dr. Lloyd as he had the Vice-Chair s finding of fact (Decision No. 1570/09I) and the worker s work history (since 1969) and a complete medical history, including a 2006 CT scan that was obtained by the Tribunal Medical Liaison Office. [40] There is no doubt that the worker had operated heavy equipment for a considerable period of time stated by Dr. Pyskylwec. However, Dr. Lloyd had a more discrete understanding of the actual months the worker worked after The worker s work history shows that he did not work a complete year after 1979, and, most often, considerably less than 12 months a year. The worker also had a period when he did not work operating heavy equipment (i.e., October 89 to June 91) as a result of a left hip injury. The worker s work history also shows that the worker worked for only seven days in 1999, two and one-half months in 2000 and for part of one month in 2001, when he retired. [41] The Vice-Chair also notes that Dr. Pyskylwec s opinion is based, to a significant degree, on the understanding that the worker, at the time of his 1989 hip injury, felt low back pain and he had chronic back pain ever since (medical report of November 2005). The Case Record materials do not support this understanding. [42] A review of the worker s family physicians medical notes (Dr. T. Tweedie), from January 1982 to March 28, 2002, show that the worker did not complain of low back problems/pain during this time period. There is no indication that the worker was treated for a low back condition nor was he diagnosed with spinal stenosis or any other form of low back degenerative disc disease. There is no indication of ongoing back injuries or loss of time from work due to back problems. [43] In January 2002 the worker was reporting problems with his hips (left worse than the right) that made the operation of heavy equipment and walking difficult. The medical diagnosis continued to be trochanter bursitis that was consistent with the worker s 1979 accident. There was no reference to back pain. [44] In September 2002 the worker was referred to Dr. V. Chari, physiatrist, for his hip problems. The worker denied any low back pain prior to the examination. A subsequent low back x-ray showed the presence of degenerative disc disease. The worker s first report of low back pain was to Dr. D. Dorcas, a Pension Medical Consultant at the Board, during a hip impairment assessment in January The worker reported that he had some low back pain without paraesthesias.

10 Page: 9 Decision No. 1579/09 [45] The Vice-Chair finds it significant that there is no temporal connection between the worker s back problems and the time he was exposed to HBV while a heavy equipment operator. There is a lack of dose-response. The worker did not report back pain or ongoing micro injuries. There is no evidence of a disease process related to his heavy job duties. [46] The Vice-Chair also finds it significant that the first evidence of DDD, by diagnostic testing, was in September 2002 approximately two years after the worker had had any significant exposure to HBV. The worker had worked 2 ½ months in 2000 ending in October of that year. The worker s first complaint of back pain was in January 2003 when the worker was 54 years old. The diagnostic testing and back complaint are consistent with the accepted medical opinion that osteoarthritic pain/problems usually occur in the general population in the fifth decade. [47] The Vice-Chair also notes that the x-ray and CT scans in 2002 did not demonstrate an advanced arthritic condition. The x-ray showed only mild DDD and arthritic changes while the CT scan showed some acquired stenosis at L3/4 and L4/5 disc spaces (emphasis - the Vice- Chair s). [48] These minor medical findings are not, in the Vice-Chair s opinion, referring to the Tribunal s Discussion Paper and the comments of Dr. Lloyd, inconsistent with degenerative findings in a 54 year old individual in the general population. It is worth while noting that Drs. Harris and Fleming did not believe that spinal stenosis was caused by trauma. [49] The worker s DDD condition of the low back has gradually worsened since leaving work in The January 2006 CT scan shows that the neural foramen is somewhat narrowed due to osteophytes and degenerative bony changes resulting in mild impingement on the left L3 nerve root. This finding is consistent with the worker s reports to Dr. Pyskylwec in November 2005 and in his testimony at the hearing. The worker testified that his back symptoms had worsened after he left work. The worker had advised Dr. Pyskylwec that his back condition had progressed over the last number of years. The worker testified that his pain symptoms increased after leaving work when he was no longer exposed to HBV. [50] The Vice-Chair concludes, based on all the evidence and for the reasons previously stated, that it is more probable than not that the worker s low back degenerative disc disease (osteoarthritis), first observed by x-ray in 2002, was as a result of a gradual aging process and not his operation of heavy equipment and exposure to HBV.

11 Page: 10 Decision No. 1579/09 DISPOSITION [51] The worker s appeal is denied. [52] The worker s job duties as a heavy equipment operator did not cause, or significantly contribute, to the worker s lumbar spine condition. DATED: April 12, 2011 SIGNED: T. Carroll