The Appeal CommissionThe Workers Compensation Act of Manitoba

Introduction

This appeals deals with the causal relationship between the worker’s ongoing symptoms after May 3, 2006 and his August 3, 2005 compensable injury in the context of a pre-existing low back condition (L5-S1 isthmic spondylolytic spondylolisthesis) and a prior compensable claim with the same employer in March 2004.

Background

The worker suffered his first compensable injury to his low back on March 4, 2004 after cutting and piling wood. He complained of pain in his low back and shooting pains into his legs. He was diagnosed with lumbar sprain/strain and returned to his full-time regular duties on March 22, 2004. Despite returning to his regular duties, the worker continued to seek chiropractic care for what the worker referred to at the hearing as “nagging” back pain and shooting pains into his legs. He testified that prior to this 2004 accident he had never had any back complaints.

Then on August 3, 2005, the worker had another workplace injury. He was crouched down with his feet planted squarely on the ground with his buttocks underneath him and his back straight, tightening a bolt with a 3 foot wrench that required approximately 100 pounds of torque. His left hand was on top and his right hand on the bottom, levering the wrench upwards at about a 45 degree angle. As he was almost finished tightening the bolt, he forced hard and felt a shooting pain across his back that made him feel like vomiting. He testified that the pain he felt was similar in nature to the 2004 accident but much more intense.

He was initially diagnosed with an acute lumbosacral facet joint sprain/strain but an x-ray taken on August 11, 2005 revealed the worker’s pre-existing condition of Grade I to Grade II spondylolisthesis and spondylosis at the L5-S1. The WCB determined that the 2005 workplace accident aggravated this condition.

The worker was referred for physiotherapy. A December 7, 2005 report outlines his visits. It is noteworthy that the worker attended approximately twice a week until he returned to alternate duties on September 26, 2005. He stopped attending physiotherapy until October 20, 2005.

On October 18, 2005 the worker returned to his family physician. The medical report reads as follows:

“has history of spondilolisthisis [sic], well until today. Had been well for about 2 weeks, then woke up this am with severe back pain.”

The worker returned to physiotherapy for two visits on October 20 and 21, 2005 and then irregularly thereafter. At the hearing he testified that he avoided going to physiotherapy because he felt it increased his symptomotology.

The worker spoke to his WCB case manager on November 4, 2005. He described his symptoms as pain radiating down both legs and buttocks and stated that he had never experienced these symptoms before the compensable injury. He later added that he had not had any problems with his back at all before the 2004 claim.

The worker’s file was reviewed by a WCB medical advisor on November 24, 2005. She commented that the worker appeared to have aggravated his pre-existing condition. She also noted a phone conversation with the worker’s family physician where he indicated that the worker did not have any evidence of spondylolisthesis before the August 2005 workplace accident.

On January 5, 2006, a CT scan was taken of the lumbosacral spine. The report indicated there was minimal central disc protrusion indenting onto the thecal sac anteriorly without definite evidence of nerve root involvement at L4-L5. At L5-S1 there was Grade I spondylolisthesis secondary to pars defect of L5. There was facet hypertrophy and osteoarthritic changes.

The worker was then referred to an orthopaedic surgeon who saw him in January 2006. The worker complained of an onset of low back pain, left worse than right, and dysesthesias 4 to 5 months prior to the visit. He stated that his leg pain was constant and had been getting progressively worse. The back pain was sharp but more intermittent in nature. The surgeon diagnosed the worker with L5-S1 isthmic spondylolytic spondylolisthesis with approximately 25% translation, moderate disc space narrowing, and no lumbosacral kyphosis. He thought that the worker’s condition was due to a fatigue fracture through the pars at L5 and S1 that had been present for a prolonged period of time. He felt however that the workplace accident had exacerbated it. Though there had been some slight improvement in the worker’s condition it was not satisfactory. Surgery was recommended and later agreed to by the worker.

On February 14, 2006, the WCB medical advisor reviewed the file. It was her opinion that the workplace accident only aggravated the worker’s pre-existing spondylolisthesis and did not enhance it.

The file was also reviewed by a WCB orthopaedic consultant on April 18, 2006. It was his opinion that the worker’s symptoms were consistent with the natural history of spondylolisthesis – onset of symptoms in late teens, early 20s. He also thought that this workplace accident as well as the one in 2004 were simply aggravations of the pre-existing condition. He did not believe there had been an enhancement.

The orthopaedic surgeon disagreed with this opinion. On May 17, 2006, he wrote:

“…He did mention that he had had back symptoms for approximately 4 years, however, he also mentioned a work-place injury that occurred approximately 4-5 months prior to the visit that exacerbated the symptoms.

…the etiology of this spinal deformity is one of a fatigue fracture through the parts (sic) of L5 and S1, and it has been present for a prolonged period of time. However, in the recent past, there was clearly an exacerbation of symptoms, which [the worker] did associate with a lifting incident at work.

Because of the clear differentiation of symptoms between his chronic pain, and the exacerbation with the lifting incident at work, it is my impression that the work-place incident contributed to the worsening of his symptoms.”

The WCB orthopaedic consultant remained adamant about his opinion. On June 27, 2006, he confirmed his initial opinion that there had been no enhancement of the pre-existing condition. He added that the worker’s accident report only referred to him using a wrench to tighten bolts at work.

The orthopaedic surgeon attempted to explain his position further in a November 14, 2006 report that he drafted after having performed surgery on the worker in September 2006:

“There were no additional findings during surgery that could have been a direct result of a workplace lifting injury. [The worker’s] underlying diagnosis of an L5-S1 isthmic spondylolytic spondylolisthesis is a pre-existing fracture of the L5 vertebral body that [the worker] probably sustained at a very early age. This is normally found in an approximate 5% of the asymptomatic population. It is very common for these pre-existing injuries, however, to be exacerbated by either a major or minor trauma, and these symptoms persist to the point where surgical intervention is necessary. This appears to be the situation with [the worker]. Whether [the worker’s] pre-existing condition would have deteriorated to the point that it did if the workplace injury did not occur, is speculative. I do not feel it is reasonable for me to comment as to the natural history of an ischemic spondylolytic spondylolisthesis as it is extremely variable. I think it is clear, however, that in [the worker’s] case, the injury that occurred in the workplace had a very temporal relationship to the onset of his symptoms, and even though he may have had a pre-existing condition, the injury that he sustained at work was responsible for the symptoms that led to the surgery.”

A second WCB orthopaedic consultant reviewed the case at Review Office’s request. In response to questions posed by Review Office, the consultant was of the opinion that the compensable injury aggravated the worker’s pre-existing condition leading to an exacerbation of the worker’s back symptoms and that there was no medical evidence that the compensable injury enhanced the worker’s pre-existing condition. No rationale was provided for this opinion.

At the worker’s request, a spine fellow who worked with the orthopaedic surgeon provided an April 5, 2007 report concurring with the treating orthopaedic surgeon’s opinion.

Worker’s Position

The worker says that his appeal should be accepted as he never recovered from the effects of his August 3, 2005 accident. He says that although he had some fairly good days, these were simply days where he could get up and walk around. At no point did his symptoms abate to the point they were at prior to the accident. He also says that this workplace injury caused an enhancement of his pre-existing condition.

Employer’s Position

The employer says that the worker’s appeal should not be accepted. It says that the evidence suggests that the worker only suffered an aggravation of his pre-existing condition which had resolved before October 18, 2005.

Analysis

To accept the worker’s appeal we must find on a balance of probabilities that the worker’s ongoing symptoms after May 3, 2006 are causally related to his compensable injury. We are able to make that finding.

The evidence before us is that the worker suffers from a pre-existing back condition known as spondylolytic spondylolisthesis. As stated by the orthopaedic surgeon and the WCB orthopaedic consultant, this condition can be either symptomatic or asymptomatic and can, through natural progression of this condition, deteriorate to the point of requiring surgery. It can also be exacerbated by either a major or minor trauma to the point where surgical intervention is necessary.

In the case before us, we must determine whether the worker’s symptoms after May 3, 2006 were due simply to the natural progression of his condition or his compensable injury or a combination of both. The worker’s back condition prior to and after his compensable injury is essential to this determination.

The worker says that prior to 2004, his first compensable injury, his back was asymptomatic. Though the orthopaedic surgeon made reference to a 4 year history of back complaints, the worker’s family physician noted that there was no prior history. The worker did concede however that after his 2004 accident he did continue to seek chiropractic care for back complaints. We note however that the worker continued to work at his regular duties despite his complaints. We also note that this changed dramatically after the August 3, 2005 workplace accident. Since that date, the worker’s back condition took a turn for the worse and continued to deteriorate to the point that he used a wheelchair after May 2006 for ambulation.