The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker has a claim with the Workers Compensation Board (“WCB”) for a low back injury that occurred in the workplace in early February 2008. His claim for compensation was initially denied by primary adjudication but was later accepted by Review Office based on the diagnosis of a strain superimposed on a pre-existing condition. Review Office further determined that the worker was entitled to 12 weeks of wage loss benefits in relation to his February accident and that any ongoing back complaints beyond the 12 week period were related solely to his pre-existing back condition. The worker disagreed with the decision and an appeal was filed with the Appeal Commission through the Worker Advisor Office. A hearing was held on January 28, 2010 to consider the matter.

Issue

Whether or not the claim should be accepted on the basis of a strain superimposed on a pre-existing condition; and

Whether or not the worker is entitled to benefits beyond 12 weeks.

Decision

That the claim should be accepted on the basis of a strain superimposed on a pre-existing condition; and

That the worker is not entitled to benefits beyond 12 weeks.

Decision: Unanimous

Background

The worker filed a claim with the WCB for a low back injury that occurred while working at a logging site on February 5, 2008.

On his application for compensation benefits, the worker reported that he first noticed low left back pain about mid January 2008 as well as pain in his neck and left shoulder. The worker commented that he had a previous 2005 WCB claim for right sided pain that went down to his right leg and ankle and that he had been off work for 2 years. On December 23, 2007, he returned to work with a different employer (the accident employer) performing the same type of work. The worker indicated that he tried to continue working from mid January to February 8 but had to stop work because he could not take the pain.

The file contains a report from a physical medicine and rehabilitation specialist dated December 10, 2007. He reported that the worker had a three year history of low back pain and that in March 2007, a fusion was performed at the L4-5 level. The worker had ongoing back pain and some mild leg pain with subjective decreased sensation in the L4 through S1 dermatomes in the right leg. His motor power seemed to be intact and there was no reflex loss. The specialist noted that it would be difficult for the worker to return to work because of the high physicality of his job. The worker was in a deconditioned state and would have increased pain when he did return to work.

A letter from the employer dated February 21, 2008, indicated that the worker was hired as a chainsaw operator but also worked the skidder. The employer indicated that they did not recommend operating the skidder as it was known that the worker had a previous back injury. Nevertheless, the worker wanted to work additional hours, and so he was given the opportunity to operate the skidder. On his first day operating the skidder, the worker was asked if he was experiencing any pain and he replied that things were okay. The worker worked until 12:00 p.m. on February 8 and was scheduled to return to work the following day. He did not return that day and did not call until February 13, stating that he would not be returning to work and was seeking medical treatment for his back pain. On February 21, 2008, the worker told the employer that he was applying for compensation as a result of his injury from two years ago and that his injury did not occur while working for the accident employer.

On March 13, 2008, primary adjudication asked the treating physician to provide a report related to the worker’s back complaints in January and February 2008. In a response dated March 20, 2008, the treating physician reported that he saw the worker on January 25, 2008 and his back had gotten worse since he starting working again. The worker suffered back pain when lifting and bending. He was prescribed medication and was instructed not to work. He was seen again on February 19, 2008 with the same problem of pain going down the right leg. On February 21, 2008 his back was not improving and he was sent for an x-ray and was referred to a specialist.

In a decision dated April 7, 2008, primary adjudication determined that no responsibility would be accepted for the worker’s claim. The adjudicator noted that the worker operated the skidder partial days for 1.5 weeks and that he was fine after operating the skidder on the first day. Given the short duration of operating the skidder and the delay in reporting the incident, the WCB was unable to confirm that the worker’s back difficulties arose out of his employment.

On April 9, 2008, the treating surgeon advised the family physician that the worker reported persistent low back pain since re-injuring his back in February 2008. Clinically, the worker’s forward flexion was limited with hands reaching down to his knees only and an extension pattern was noted. The neurological exam confirmed an L5 radiculopathy with toe weakness and sensory changes. The ankle reflex was absent on the right side and there was mild localized tenderness at the L5-S1 level. The surgeon concluded that the worker probably had an adjacent level disc herniation at L5-S1 below his previous L4-5 fusion. A MRI scan was suggested to define the problem.

On July 10, 2008, a worker advisor asked the WCB to reconsider its decision of April 7, 2008 based on the results of an MRI examination taken in May 2008 and a report from the treating surgeon dated June 24, 2008. The worker advisor submitted that these reports provided medical evidence to support that the L3-4 disc herniation was causally related to the worker’s job duties in January 2008 as a skidder operator.

The MRI results of May 28, 2008 were read as follows:

“…Since the previous examination of Apr. 2006, the patient has had a prosthetic disc inserted at the L4-5 disc space and internal fixation with posterior screws and rods in L4 and L5.

L3-4: No significant abnormality is seen.

L4-5: The previous left central disc protrusion is no longer seen. There is some artifact from the metallic rod. No other significant abnormality is seen.

L5-S1: There is mild facet joint osteoarthritis and a very small central disc protrusion, which does not appear to be affecting the thecal sac or nerve root. There is no enhancing scar tissue. No other significant abnormality is seen.”

In his June 24, 2008 report to the worker advisor, the treating surgeon stated the following:

“The patient did in fact return for the MRI scan on May 28. This confirms an additional problem at the L3-4 level. This is the level above his previous operation. There is certainly significant stenosis at this level. In addition, there is a very small central disc herniation at L5-S1, the level below his previous surgery. At the level of his previous operation, no additional pathology is noted.

Please note also quite a large far lateral disc herniation at L3-4 which certainly will explain the patient’s left-sided leg pain.

The patient, therefore, has chronic spinal stenosis with an L3-L4 disc herniation for lateral. This probably is related to the injury as described in February 2008. The far lateral disc herniation on the left side would certainly explain that. At the moment no further surgery is prescribed and we hope to contain his pain with conservative measures.”

On August 26, 2008, the family physician reported that the worker was seen on December 5, 2007 for a refill of pain medications for his low back pain. He said he saw the worker in September and October 2007 for the same complaint.

X-rays of the lumbar spine dated September 4, 2008 showed a metallic prosthesis in the L4-5 disc space and that the posterior screws and rods in L4 and L5 had remained unchanged from May 2007.

On September 4, 2008, a WCB medical advisor outlined the opinion that it was more than probable that the worker had an L5 radiculopathy in April 2008 that was not present on December 10, 2007.

On September 10, 2008, the treating surgeon reported the following to the worker’s family physician:

“The patient was seen again with more intense pain to his back and leg. He indicates the pain now is a scale of 8/10. The back pain is worse than the leg pain. The back pain is typically in the mid lumbar area. The leg pain affects the right side and affects especially the L4 dermatome. This is associated with loss of pain sensation which was confirmed clinically.

As mentioned before he does have a far lateral disc herniation at L3-4. I notice from my reports that the radiologist did not mention this in his report…”

Due to discrepancies in the interpretation of the April 26, 2006 and May 28, 2008 MRI results, an independent radiologist attended the WCB on October 2, 2009 to review the MRI images. His findings were documented as follows:

“Comparison is made with the previous exam from April 26, 2006. In the interval an L4-5 discectomy has been performed. There are now posterior surgical rods and screws transfixing the L4 and L5 vertebra. The metal artefact from the surgical instrumentation degrades image quality. A prosthetic L4-5 intervertebral disc is now identified. There is some shallow posterior disc bulging without definite evidence of residual recurrent disc herniation without evidence of spinal stenosis or nerve root compression. There does not appear to be any significant post surgical epidural scar tissue. There has been no other interval change. Specifically, at the L3-4 level there is no evidence of a lateral disc herniation and no other significant abnormality is noted.”

On November 3, 2008, a WCB case manager determined that no change would be made to the original decision of April 7, 2008. The case manager stated that she found no medical evidence to support that the worker sustained a new injury or worsening of any pre-existing injury during his employment with the accident employer and therefore the WCB was unable to establish that the worker sustained an injury that arose out of his employment. On November 24, 2008, the worker advisor appealed the decision to Review Office.

On December 4, 2008, Review Office determined that the claim was acceptable as a strain and that the worker was entitled to 12 weeks of wage loss benefits.

Review Office took the position that the worker’s back was predisposed to injury and at risk due to his underlying lumbar condition and being inactive for two years prior to his employment with the accident employer. Review Office believed that the expectations placed on the worker’s lumbar region in the six weeks he had been at work for his new employer had produced a lumbar strain superimposed on a back at risk. Review Office felt that the worker was entitled to 12 weeks of benefits based on the recovery norm for a lumbar strain superimposed on a back which had the conditions evident through the MRI evidence. Review Office felt that the worker’s back condition beyond the 12 week period was related to his pre-existing back condition and that the worker would be back to the lumbar status he was prior to December 2007.

On March 20, 2009, the worker advisor asked Review Office to reconsider its decision of December 4, 2008. The worker advisor’s position was that the January 28, 2008 injury was not a strain/sprain injury but rather a disc herniation at L3-4. Included with the submission was a report from the treating orthopaedic specialist dated January 27, 2009 which stated:

“He still complaints of persistent back and leg pain. The leg pain is typically in the L4 dermatome. As mentioned, he does have a far lateral disc herniation which was not mentioned by the radiologist. I recommend that the Workers Compensation Board request a review of the MRI as I believe there is a lateral disc herniation at L3/4 causing his symptoms at this stage.”

Prior to considering the appeal brought forward by the worker advisor, Review Office obtained the following opinion from a WCB orthoapedic consultant dated April 1, 2009:

“I have reviewed the entire file. In his letter dated January 27, 2009, the orthopaedic surgeon stated, in part, “I believe there is a lateral disc herniation at L3/4 causing his symptoms at this stage.” Both interpretations of the MRI by the reporting radiologist and the orthopedic surgeon are mutually exclusive. Only one can be correct. It was appropriate to have an expert radiologist review the MRI and determine which interpretation was correct. This step has been completed. The weight of credibility is with the experienced radiologist. There is no benefit with respect to resolution of the dispute in seeking further opinions on the interpretation of the MRI.”

On April 2, 2009, Review Office confirmed its previous decision that the diagnosis related to this claim was a strain superimposed on the pre-existing condition and that wage loss benefits to the worker should not extend beyond 12 weeks. Review Office noted in its decision that it agreed with the opinion expressed by the WCB orthopaedic consultant. It stated that the point made by the consultant was that an expert in the field of interpretation of the imaging study had already been involved in the claim and thus, there was no one in the medical community that had standing above an expert radiologist regarding interpreting an MRI. Review Office indicated that the philosophy used in its decision of December 4, 2008 should not be altered.

On May 28, 2009, the worker advisor asked Review Office to reconsider its decision of April 2, 2009. The worker advisor quoted the following opinion from a “head radiologist” outlined in his report of May 27, 2009:

“I reviewed the MRI study of the lumbar spine with contrast dated May 28, 2008 on [the worker].

IMPRESSION: Right lateral disc protrusion at L4-5 extending just below the level of the disc as well as some right far lateral disc material in the neural forament, best demonstration on the sagittal views. Irritation of the exiting right L4 root and the traversing right L5 root may be present and should be correlated with clinical findings.”

The worker advisor indicated that the above report provided medical evidence of a relationship between the worker’s ongoing lumbar difficulties and the January 28, 2008 injury.

In a memo to file dated June 10, 2008, the independent radiologist outlined his opinion as follows:

“I have re-reviewed the MRI scans from [source] dated April 2006 as well as May 2008.

The MRI scans were of the lumbar spine. My report from the examination from 2006 is correct as it stands. Re-reviewing the post-operative MRI scan from 2008 as well as the report from [head radiologist], I would note that at the L4-5 level, a left sided discectomy has been performed successfully without residual recurrent left sided disc herniation. On the sagittal images, there is some right posterolateral disc bulging or a tiny disc herniation which persists unchanging the pre-operative scan but the disc material is quite small in size and does not extend into the right L4-5 intervertebral foramen. As mentioned on the 2006 report, the disc material approaches the right L5 nerve root but I do not believe there is convincing evidence of compression of the right L5 nerve root by the disc material given its small size and the disc material on the right is essentially unchanged from the pre-operative scan. Clinical correlation of course would be helpful in this regard.”

In a letter dated July 7, 2009, Review Office outlined its opinion that on a balance of probabilities, the worker’s compensable strain situation from early February 2008 had not produced a significant diagnosis which would currently be the cause of his ongoing subjective complaints of pain and impaired function. After reviewing all the evidence, Review Office felt that the worker had been adequately compensated for the results of the trauma to his low back in early 2008. Review Office indicated that it placed significant weight on the fact that the worker was attending medical treatment for his back condition pre-dating this claim which showed that he had significant lumbar back problems. On July 14, 2009, the worker advisor appealed Review Office’s decision to the Appeal Commission and a hearing was held on January 28, 2010.

Following the hearing, the appeal panel requested additional medical information from two of the worker’s treating physicians. On May 5, 2010, the information received from the two physicians was provided to the interested parties for comment. On May 21, 2010, the panel met to render its final decision on the issues under appeal.

Reasons

In the panel’s opinion, it is clear that the worker had pre-existing symptomatology prior to the February 2008 accident, which was steadily worsening. In the absence of any convincing evidence of a significant injury to the lumbar spine, the panel finds on a balance of probabilities that the injury suffered by the worker in respect of this claim was limited to a strain superimposed on a pre-existing condition. It follows that the worker is not entitled to benefits beyond 12 weeks on the claim. The worker’s appeal is therefore dismissed.

Panel Members

L. Choy, Presiding Officer
A. Finkel, Commissioner
P. Walker, Commissioner

Recording Secretary, B. Kosc

L. Choy - Presiding Officer

Signed at Winnipeg this 5th day of July, 2010