The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

This appeal deals with the causal relationship between the worker’s ongoing back complaints and her compensable injury of February 17, 2003.

On February 17, 2003 the worker suffered an injury to her back when she lifted her right leg over her left. She filed a claim with the Workers Compensation Board (the “WCB”) which was accepted. She received benefits until November 8, 2004 when the WCB determined that she was able to return to her regular duties. The worker disagreed with this decision and appealed it to the Review Office which upheld the termination of benefits. It is in this context that the worker filed an appeal with the Appeal Commission.

An appeal panel hearing was held on September 19, 2006. The worker appeared and provided evidence. She was represented by a union representative. The employer also appeared and was represented by an advocate.

Issue

Whether or not the worker is entitled to wage loss and medical aid benefits beyond November 8, 2004.

Decision

That the worker is not entitled to wage loss and medical aid benefits beyond November 8, 2004.

Decision: Unanimous

Background

Reasons

Introduction

As stated in the Preamble, this appeal deals with the causal relationship between the worker’s ongoing back complaints and her February 17, 2003 workplace accident. More specifically, it deals with whether the disc conditions at the L3-4 and L4-5 levels are related to the workplace accident and whether they caused her a loss of earning capacity after November 8, 2004.

The worker says that the workplace accident caused her a disc herniation at the L3-4 level and a disc protrusion at the L4-5 level. She says that she has suffered from the effects of both of these conditions since the workplace injury to the extent that they are painful and prevent her from returning to her regular duties. She says that the WCB has essentially ignored her L4-5 injury which continues to digress.

The employer disagrees. It says that the worker’s ongoing back complaints are more likely related to her pre-existing degenerative back condition than her compensable injury. It points to the relatively minor mechanism of injury, the diagnosis, pre-existing back problems and the radiographic evidence that the worker’s disc herniation was resolving to support its position that the worker had long recovered from her compensable injury.

Background

On February 17, 2003 while at work, the worker lifted her right leg over her left leg to put on a shoe when she felt immediate pain in her lower back through the front of her pelvic region. She experienced difficulty standing up and walking. It was initially thought that the worker had suffered a back strain on top of a pre-existing degenerative back (which was confirmed on x-ray). However, when the worker continued to be symptomatic and complained of increased pain upon returning to work in April 2003, a CT scan was performed which revealed a disc herniation at L3-4 and disc bulging at L4-5:

“At L3-4, there is a central and left sided disc herniation which is significantly indenting the thecal sac at this level, and displaces [it] posteriorly. There may be left sided foraminal involvement at L3-4 by disc material. The herniated disc extends inferiorly from the disc level approximately 1.5 cm.

There is mild central disc bulging at L4-5, but no evidence of focal disc herniation.”

Despite these findings and the worker’s continuing pain complaints, the worker’s treating physical medicine and rehabilitation specialist found her clinical presentation to be relatively normal and her symptoms few, though some could have been attributable to an L3-4 disc herniation. He commented that the worker reported that she was getting better but was still “self-limiting her activity”. He thought that this self-limitation was “in part responsible for her current level of function”.

This was essentially the opinion of the WCB medical advisor in November 2003. Indeed, he thought that the workplace accident possibly caused a back strain and an aggravation to a pre-existing degenerative back. He did not think the mechanism of injury was typical for a disc herniation. He thought that the worker should return to work with temporary restrictions of no lifting greater than 25 pounds, and no repetitive bending or lifting, with an ability to change position as needed.

It is in this context that the worker gradually returned to work at light duties on December 4, 2003. A call-in examination with the WCB medical advisor one month later revealed that the worker was dealing with her return to work adequately and was physically able to gradually increase her hours to full time followed by a gradual increase to her regular duties. It also revealed that there was no nerve root involvement. The WCB medical advisor thought that this finding suggested that the disc herniation might simply be incidental and that the cause of the worker’s pain complaints might be due to mechanical back pain with some myofascial component.

The gradual increase in work hours and duties was endorsed by the treating physical medicine and rehabilitation specialist in a March 9, 2004 report. At that time, he also stated that he could not provide a precise anatomic diagnosis for the worker’s symptoms.

Despite the advice of the WCB medical advisor and the treating physical medicine and rehabilitation specialist to increase her hours and work duties, the worker, with the approval of her family physician, remained at a reduced work day on light duties until late summer 2004 when she began working 2 hours of regular duties in addition to 4 hours of light duties. The worker found these regular duties increased her symptoms. She saw her family physician who recommended a return to only light duties.

This return to light duties was put to the WCB medical advisor on September 9, 2004. He disagreed with limiting the worker to light duties only and thought that the graduated return to work with mixed regular and modified duties was reasonable. He was also at a loss to explain the worker’s ongoing symptoms:

“There is no anatomical explanation to describe her ongoing symptoms as they relate to the [compensable injury]. The L3/4 prolapse could possibly be causing symptoms however I do not feel that the [mechanism of injury] would have caused a disc prolapse.”

A second CT scan was taken of the worker’s lumbosacral spine on September 21, 2004 which revealed the following:

“1. Significant interval improvement in the previously identified L3-4 disc herniation.

 2.  Mild to moderate central spinal stenosis at L4-5 secondary to broad-based posterior disc bulging and a tiny central disc herniation as well as facet degenerative changes and mild ligamentum flavum prominence.”

The worker was then called in for an examination by the WCB medical advisor and a WCB physical medicine and rehabilitation consultant on November 25, 2004. These two medical advisors also questioned the causal relationship between the workplace injury and the disc herniation. Simply, they did not think that the mechanism of injury was likely to cause one. They thought it more likely that the worker had a pre-existing degenerative back condition that was aggravated by the workplace injury and that this aggravation had resolved to the point that she was able to return to her full time duties with restrictions.

The worker continued to complain of back pain and was supported by her family physician in her reduced physical capacity. He referred her to an orthopaedic specialist who ordered a CT lumbar myelogram that revealed the following:

“At L3, L4 there is left posterior and paracentral disc prominence with mild compression of the left anterior surface of the thecal sac. No appreciable nerve root compression or spinal stenosis is identified.

At L4, L5 there is a small to moderate sized central disc protrusion with compression of the anterior surface of the thecal sac. No appreciable root compression is identified.

The L5-S1 level in unremarkable.”

Bilateral lumbar facet blocks at the L4-5 and L3-4 levels were done without any resolution of the worker’s pain complaints. The orthopaedic specialist ultimately concluded that the worker’s ongoing back complaints were due to mechanical back pain. He recommended that she continue to stretch and exercise as best able.

An orthopaedic consultant to the Review Office, who reviewed the file on November 25, 2005, essentially agreed with this assessment of the reasons for the worker’s ongoing back complaints. He opined that the ongoing symptomotology was caused by pre-existing degenerative disc disease and residual symptoms related to her disc herniation. However, he did not agree with the previous comments about the injury caused by the workplace accident. Indeed, he thought that the mechanism of injury was typical for a disc herniation.

Analysis

To accept the worker’s appeal, we must find that her ongoing back symptomotology is related to her compensable injury and that it caused her a loss of earning capacity after November 8, 2004. We are unable to make these findings.

Though there is some suggestion by the WCB medical advisor and the WCB physical and rehabilitation specialist that the mechanism of injury was unlikely to have caused a disc herniation, the orthopaedic consultant to the Review Office says that it is a typical mechanism of injury.

Disc herniations can be caused by degeneration or by an acute injury. In this case, the worker described her injury as a loud pop in her back with immediate excruciating pain and symptoms into her legs. Given the absence of radiographic testing before the workplace injury, it is impossible to say precisely whether the workplace accident caused a disc herniation. That said, the onus of proof is only on a balance of probabilities. In other words, we must find it more likely than not that the workplace injury caused a disc herniation at L3-4. We find, based on the worker’s description of her accident and her symptoms immediately thereafter, that the mechanism of injury more likely than not caused a disc herniation at the L3-4.

We do not however, make that finding with respect to the disc bulging at the L4-5. Indeed, disc bulging is typically degenerative in nature. Though the union representative submitted that the disc bulging must have been caused by the workplace accident and that it was simply ignored by the WCB, we are unable to accept that. Indeed, all of the medical practitioners that examined the worker or her medical file were privy to the CT scan results. The fact that it was not specifically mentioned might have more to do with the insignificance of this finding or its relationship to the workplace accident. We also note that the treating orthopaedic specialist did facet blocks in this particular disc with no change to the worker’s reported symptoms.

In any event, we find that neither of these conditions caused the worker to suffer a loss of earning capacity after November 8, 2004. Indeed, the reports of the medical practitioners, with the exception of the family physician, all indicate that the worker was physically capable of working full time as of November 8, 2004. The only thing preventing her from doing so was her own self-limitation. This self-limitation was, as mentioned, accepted by the family physician. Unfortunately, no sufficient rationale was provided by him for limiting the worker’s functional capacity. We therefore place less weight on his recommendations and we would therefore not place any compensable medical restrictions on the worker.

We have turned our minds as to whether the worker’s ongoing symptomotology and pain complaints are related to the compensable injury. The main of the medical evidence is that the worker suffers from mechanical back pain as a result of her pre-existing degenerative disc disease and that her symptomotology cannot be accounted for by her physical condition. We did not note any medical evidence that would suggest that the worker suffered from a chronic pain syndrome. We therefore find that there is insufficient evidence to demonstrate that the worker’s pain complaints are causally related to the workplace accident.

Given the foregoing we find on a balance of probabilities that the worker is not entitled to wage loss and medical aid benefits beyond November 8, 2004.

Accordingly the worker’s appeal is denied.

Panel Members

L. Martin, Presiding Officer
A. Finkel, Commissioner
M. Day, Commissioner

Recording Secretary, B. Kosc

L. Martin - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 2nd day of November, 2006