The Appeal CommissionThe Workers Compensation Act of Manitoba

In this regard we note the following evidence:

• the initial diagnosis was a lumbosacral strain with a mechanical component. Impression on the x-ray revealed an L5 transitional segment, facet trophism and mild lumbar scoliosis;

• CT scan of the lumbosacral spine performed February 14, 1995 demonstrated:

“mild diffuse bulging of the L3-L4 and L4-L5 disc with no evidence of any deformity of the adjacent thecal sac or nerve roots. There is also diffuse posterior bulging of the L5-S1 disc which is more pronounced. The changes are slightly more pronounced on the right approaching the thecal sac and resulting in some minor posterior displacement of the right S1 nerve root. The spinal canal was also noted to be congenitally small at this level. There is also some mild hypertrophy of the ligamentum flavum and degenerative changes of the posterior facets at this level.”

• a WCB chiropractic consultant examined the claimant on January 19, 1995 and indicated that the claimant was deconditioned and after reconditioning could return to work, he stated:

“Following my examination and consultation with Mr. [the claimant] it is my opinion the result of the accident dated September 19, 1994 in all probability, is a musculoligamentous strain/sprain type of injury to the lumbosacral spine. I do believe there is a mechanical element involved in this injury involving the lumbosacral mechanism.”

• a WCB orthopaedic consultant was asked to review the file and comment on the CT results of February 14, 1995. In a memorandum dated March 29, 1995 the orthopaedic consultant indicated:

“ I don’t think ‘bulging discs’ are of much significance. Disc herniations are almost always at one level. The CT also showed facet joint degeneration and hypertrophy of the ligamentum flavum. This would be a pre-existing condition that may be aggravated by his work.

He may have a myofacial strain or an aggravation of the pre-existing condition.

He should have recovered by now from the “strain” or aggravation of the pre-ex. It was an unusual type of injury & that is more consistent with an aggravation.”

• in response to the question whether the lifetime restrictions suggested by the attending physician were related to the pre-existing condition, the medical advisor indicated that they would be related to the pre-existing condition;

• CT myelogram of the lumbar spine performed May 11, 1995 revealed:

“ There is diffuse bulging of the annulus at L4-L5. This together with hypertrophy of the ligamentum flavum and a moderate quantity of epidural fat results in a mild central spinal stenosis at this level. No focal disc protrusion or nerve root compression is identified.”

• in a report dated June 12, 1995 the attending physician indicated:

“1- regarding Mr. (the claimant’s) pre-existing condition which are a) lumbar type Vertebrae with incomplete Fusion of L5 to the sacrum b) Congenitally small Spinal Canal. c) Degenerative changes of the Posterior Facet at S1. Mr. (the claimant’s) degenerative bone disease appear to be generalized, since he showed Degen. Changes of the Medial Malleolus of his Rt. ankle (Jan.20/95) & Degenerative changes of the Rt. Acromio-clavicular Joint on May 2/88.

2/3- Mr. (the claimant) is still suffering from pain of the Lumbo-Sacral region, probably as a result of the accident which in turn aggravated the pre-existing conditions.”

• in a report dated September 25, 1995 a consulting specialist in rehabilitation and physical medicine indicated:

“Organ imaging to date has shown some degree of lumbosacral disc degeneration with a transitional first sacral segment which is lumbarized.”

• in a report dated May 29, 1995 a consulting orthopaedic surgeon indicates:

“Mr. [the claimant] had a lumbar myelogram at [a local hospital] on May 11, 1995. He has four lumbar type vertebra with the 5^th lumbar vertebra not being functional. All nerve roots filled out well on the myelogram. The previous CT Scan at [a local hospital] stated that the spinal canal was congenitally small. This indeed is true, but there was no evidence of disc displacement, nerve root entrapment or spinal stenosis. Hence he is suffering from mechanical problems to his back.” (emphasis ours).

• a CT scan of the lumbosacral spine performed June 25, 1996 revealed:

“The patient has four lumbar type vertebra with near complete fusion of the 5^th lumbar vertebra to the body of the sacrum. The L2-3 disc is mildly prominent posteriorly diffusely without focal disc protrusion or nerve root compression suggested. Similar changes are present at L3-4. At L4-5, there is diffuse shallow central disc protrusion which approaches the dural sac and may just approach the L5 roots. The lumbosacral level is unremarkable. The patient has a congenitally narrow spinal canal with diffuse central stenosis which becomes accentuated at the L4-5 level due to the central disc protrusion.”

• in further reports dated August 13, 1996 and March 3, 1998 the consulting orthopaedic surgeon indicates respectively that:

“this man appears to have purely mechanical lumbar back pain, either from musculoligamentous strain or disc strain, there is no evidence of nerve root entrapment.”

“It was approximately two years after the tractor riding complaints before Mr. [the claimant] was seen. Therefore I can only state that historically the symptomatology appeared at the time of the tractor riding and seems to have persisted. There is no x-ray evidence of any pre-existing condition that may have been aggravated or enhanced.

It is difficult to state that all of Mr. [the claimant’s] ongoing symptomatology would be directly related to tractor driving in a ditch, however, there is no exact measure to decide this.”

• in a subsequent report dated May 29, 1997 the consulting specialist in rehabilitation and physical medicine further indicated:

“The second [principle presentation] was a continuing element of mechanical low back pain which remained after treatment at a reduced level. This discomfort appeared to be coming from the posterior vertebral joint and radiographically there were degenerative changes in these joints.

In my opinion, the nature of this patient’s work in cutting ditch slopes carried a high probability of rendering the degenerative joint changes symptomatic and, in particular, causing muscle overload to produce a regional myofascial pain syndrome in the muscles of the low back and pelvic girdle.”

• On March 17, 1998 a WCB orthopaedic medical advisor reviewed the file and indicated:

“The C.T. scan of the lumbar spine Feb. 15, 1995 reports OA of the posterior facet joints which is pre-existing and a more likely cause of ongoing back symptoms than any musculoligamentous strain that occurred as a result of the mower riding on an angled slope 3 ½ years ago.”

• in a report following neurophysiological testing carried out on April 14, 1998 a consulting neurologist indicates in his clinical notes:

“Chronic low back pain with prior history of degenerative disc disease and prolapse, surgery, chronic numbness involving heels bilaterally.”

The MRP was convened on May 15, 1998 and was asked to respond to ten questions. The panel indicated that the most probable diagnosis following the 1994 accident was a low back strain. To support this diagnosis the panel found little in the way of objective clinical findings, but noted a clear description of localized back pain and tenderness and a description of right leg pain which began in December 1994. The panel gave their further opinion that the claimant had no pre-existing spinal condition prior to the accident. Therefore the accident did not cause an aggravation or enhancement of a pre-existing condition.

The panel was asked to determine a diagnosis for the claimant when benefits were discontinued in April, 1995. The panel gave their opinion that the claimant had a localized low back pain and tenderness which had progressed to a chronic low back strain; and that the present diagnosis was low back pain which appeared to have its onset at the time of the compensable injury in 1994 and had progressed to a chronic type of low back pain. The panel were of the view that the claimant had not recovered from the effects of the injury and that his back pain has become chronic.

• A senior medical advisor to the WCB was asked to review the findings of the MRP, specifically that the panel found no evidence of a pre-existing spinal condition. The medical advisor commented on August 19, 1998:

“I find this extremely difficult to comprehend given the information on file and I note also, at the time of the Medical Review Panel, during the claimant interview, Mr. [the claimant] stated that following a 1986 accident he had made a full recovery and had no further problems until the compensable injury of September, 1994. If this were the case, I have difficulty in seeing the rationale of an attending physician requesting a CT scan of the lumbar spine in February, 1993, as I would not think that this would have been ordered without some symptomatology being given by the claimant to the attending physician.”

With regard to the specific statement above we concur with the claimant’s representative that the reason for the referral for a CT scan by the attending physician was directly related to a prior WCB claim for a low back injury in 1993.

• The medical advisor goes on to note that the CT Scan performed in February 1995 showed degenerative changes in the posterior facets as well as thickening of the ligamentum flavum and that for these changes to be present at that time would have certainly predated the date of the compensable injury. The medical advisor further evaluates the MRP findings by stating:

“The response to question #1 by the panelists indicated that in their opinion the probable diagnosis was that of a low back strain. As previously stated, this certainly is the most likely diagnosis and was that given by the attending physician. Although as previously stated, any such strain would have been minimal given that the activity which is alleged to have brought on this condition was due to riding on a mower maintaining ones back at an oblique angle and no strenuous physical activity was involved.

In question #7 the panelists state that the claimant has not recovered from the effects of his injury but this response, in my opinion, is based on the presence of ongoing symptoms which they wrongfully relate to the effects of the compensable injury due to their failure to recognize the presence of a significant pre-existing disease which is the primary causation of ongoing symptomatology and will continue to be so.”

• all diagnostic tests were referred to an independent radiologist for an evaluation. In a report dated March 11, 1999 the independent radiologist submitted his evaluation and comparison of the various diagnostic test results. In particular we note the following from the report when the CT Scans dated respectively February 23, 1993 and June 20, 1996 were compared:

With respect to 1993:

“Again identified is the sacralization of the L5 vertebra. The L2-3, L3-4 levels appear unremarkable. There is a broad, shallow posterior disc bulging without definite evidence of disc herniation. The combined effect is a very minor central spinal stenosis, almost certainly of no clinical significance. The disc material contacts the L5 nerve roots bilaterally without definite evidence of displacement or compression of the L5 nerve roots.

At the L5-S1 level, there is no evidence of disc herniation, spinal stenosis or nerve root compression.”

With respect to 1996:

“At the L4-5 level there is mild congenital narrowing of the central spinal canal. There is a broad, shallow posterior disc bulging without definite evidence of disc herniation. The combined effect is a minimal central spinal stenosis, almost certainly of no clinical significance. The disc material contacts the L5 nerve root bilaterally without evidence of displacement or compression of the L% nerve roots.

At the L5-S1 level there is no evidence of disc herniation, spinal stenosis or nerve root compression. There has been no interval change since 1993.” (emphases ours).

• The independent radiologist further concludes that his review of the multiple radiological examinations on the claimant indicated that there was no interval change between 1993 and 1996. He states:

“The plain x-rays, CT scans and myelogram demonstrate sacralization of the L5 vertebra. In addition, at the L4-5 level, there is mild congenital narrowing of the central spinal canal. There is broad, shallow posterior disc bulging without definite evidence of disc herniation, significant spinal stenosis or focal nerve root compression. The remaining disc levels appear unremarkable. There is no evidence of malalignment or instability. The radiologic abnormalities in the lumbosacral spine appear to have predated the patient’s injury which was sustained on September 19, 1994 following the initial plain x-rays and CT scan.”

We note, following our analysis of the file, that the focus of the adjudication process in this case became completely directed toward the existence of a pre-existing condition and to it being the cause of the claimant’s ongoing symptomatology. In this regard, we find that this focus detracted from the analysis and comprehensive adjudication of the claim.

As supported by radiological, diagnostic and clinical evidence, we are of the view that the claimant does have conditions in his lumbosacral spine which pre-existed the compensable event of September 19, 1994 namely, sacralization of the L5 vertebra with mild congenital narrowing of the central spinal canal at L4-5 and broad disc bulging. However it appears to the panel that these pre-existing conditions were not thought to be of clinical significance to the MRP orthopaedic consultants, and as suggested by the opinions of the independent radiologist, and the consulting orthopaedic surgeon. We do recognize, however, that other physicians involved in this case have expressed an opposite view and that in this respect it is difficult to know whether there is any clinical significance with respect to the role, if any, that these abnormalities have in the etiology of the claimant’s symptoms.

Based on the evidence we are of the opinion that the claimant sustained a relatively minor injury based on the mechanism of accident as described by file documentation. In this regard we concur with the opinion expressed by the WCB senior medical advisor who stated on August 19, 1998:

“Although as previously stated, any such strain would have been minimal given that the activity which is alleged to have brought on this condition was due to riding on a mower maintaining one’s back at an oblique angle and no strenuous physical activity was involved.”

We find based on the weight of evidence that the most likely diagnosis resulting from the compensable event was a musculoligamentous sprain/strain injury as initially diagnosed by the claimant’s attending physician, the WCB orthopaedic and chiropractic specialists, and as confirmed by the MRP consultants. We also concur with the evidence outlined which suggests that the claimant’s ongoing symptomatology would be consistent with a diagnosis of mechanical back pain.

In support of this diagnosis, we note the claimant’s testimony at the hearing:

Q. Could you tell us what sort of activities start off the pain in your low back, sir?

A. It’s not like anything in particular. I’ve tried to pinpoint something which might do it and I – whether it’s a lifting or a moving, and I can’t point to any one thing.

I can be just sitting in a chair and all of a sudden notice the back pain. I can be standing in the kitchen finishing up the dishes and notice a back pain.

It just happens. Like I don’t have to do anything. It’s just for some reason the muscles tighten up and you end up with a back ache. It’s just – I don’t know what causes it.

In light of a diagnosis of mechanical back pain and the minimal objective findings reported by the MRP specialists we are led to conclude that the claimant had recovered from the compensable injury of September 19, 1994. In this regard we accept the evidence of the WCB orthopaedic consultant as recorded in a memorandum to file dated March 27, 1997 that: