Decision #51/11 - Type: Workers Compensation
Preamble
The worker suffered an injury to his low back in a work related accident on July 29, 2008. His claim for compensation was accepted by the Workers Compensation Board ("WCB") and benefits were paid to the worker until February 26, 2010, when it was determined that his current low back symptoms were not related to his compensable accident. The worker disagreed with the decision and an appeal was filed with the Appeal Commission. An appeal panel hearing was held on March 1, 2011, to consider the matter.
Issue
Whether or not the worker is entitled to wage loss benefits beyond February 26, 2010.
Decision
That the worker is not entitled to wage loss benefits beyond February 26, 2010.
Decision: Unanimous
Background
In an Accident Report submitted to the WCB the worker reported suffering an injury to his lower back on July 29, 2008 while employed as a labourer. He described tripping when carrying a pallet, twisting his body to the left, and immediately feeling a sharp pain. The worker was seen by a chiropractor on July 29, 2008 and was diagnosed with an acute L5-S1 strain.
On July 31, 2008 the worker presented at the hospital with increasing acute lumbago with pain going down the right leg. A July 31, 2008 X-ray report demonstrated mild lumbar spondylosis without disc narrowing, and showed normal lumbar alignment and disc spaces and normal facet and SI joints. The worker was treated in hospital for two days with traction, and prescribed pain medication. A doctor's first report referencing an examination on August 1, 2008 showed a diagnosis of a possible prolapsed disc. A CT scan of the lumbar spine dated August 18, 2008 identified a small central disc bulge at L5-S1 without root compression.
A WCB medical advisor reviewed the file on September 16, 2008. She noted the initial diagnosis by a chiropractor was an acute L5/S1strain. She indicated that the mechanism of injury and clinical information was most consistent with a low back strain. The CT did not confirm a significant disc injury and showed only a small disc bulge with no nerve impingement.
An MRI of the lumbar spine done on September 24, 2008 showed a shallow central protrusion and annular tear at L4-5 that did not affect the L5 roots. There was no significant disc protrusion at the L5-S1 level.
The WCB received information indicating that the worker had experienced back problems in the past. On August 8, 2008 the worker advised the WCB that he had prior left hip problems and “about 20 years ago back problems when the worker had a disc protrusion.” In a file note dated July 23, 2009 the case manager recorded the worker`s employment history as related to him by the worker. It included:
1996-2000 Oversaw a crew in building concrete foundations. He advised that he did not have any accidents with them, but “as this work was very physical he did have some back difficulties.”
2000-2001 Heavy equipment operator. “He did have some low back difficulties but denies any specific accidents.”
2003-2007 Exterminator. “This involved a lot of driving and he noticed the prolonged driving cause (sic) him low back pain as well.” He also recalled an accident when he slipped and fell on ice on his driveway. It “settled over time.”
A report from a chiropractor dated October 5, 2008 outlined ongoing treatment of the worker during the period from 2004 to 2008. CT scan results from 2002 and clinical chart notes were also obtained. The 2002 lumbar spine CT scan indicated small central disc herniation at L4-L5.
On October 14, 2008, primary adjudication referred the file to a WCB medical advisor to review the new information and to answer specific questions related to the worker's current medical status. The medical advisor noted that the MRI showed only an annular tear with shallow disc protrusion and there was no evidence of nerve impingement. Clinically, there was no mention of symptoms down either leg or positive straight leg raising/abnormal neurological findings to support a diagnosis of a significant disc injury. The compensable diagnosis remained a strain. It was noted that an annular tear can be traumatic in nature if the mechanism of injury increases intradiscal pressure. There was no such mechanism in this case.
The medical advisor indicated there were multilevel disc changes on the CT scan which was generally consistent with degenerative disc disease. In her view the injury would not have caused the annular tear, and this would be considered a pre-existing condition. The worker's symptoms and clinical findings were not consistent with an aggravation of his pre-existing conditions. As it was now past the recovery norm for a lumbar strain, it was most likely that the pre-existing degenerative condition was delaying the worker's recovery. The medical advisor stated there was no surgical lesion on the MRI, and the MRI findings were not particularly consistent with the worker's presentation.
Another WCB medical advisor saw the worker on February 24, 2009 for an assessment. The medical advisor noted that the September 2008 MRI reported a shallow central disc protrusion and annular tear at L4-L5. He commented that the duration and severity of the worker's current low back pain was not accounted for by a strain. A WCB physiotherapy consultant found no abnormality with regard to pelvic height asymmetry or leg length discrepancy in the worker's lower limbs. The medical advisor opined that there was no indication that the July 29, 2008 compensable injury aggravated the worker's pre-existing degenerative lumbar spine changes or that the worker's pre-existing degenerative lumbar spine changes were prolonging the duration of his reported symptoms. Based on the examination findings and radiographic investigations, the medical advisor indicated that the worker was not totally disabled.
In a narrative report to the WCB dated May 7, 2009, an orthopaedic surgeon noted that electrodiagnostic tests did not show a significant disc protrusion, and that an MRI showed no significant nerve root impingement or a disc protrusion. The worker had a positive Trendelenburg on the right but otherwise there was no indication of significant weakness or radiculopathy. He concluded that the worker would be allowed to return to work again. He referred to the worker as having a “back at risk,” and commented upon the worker’s history of prior injuries which included:
· having fallen off a ladder from a height of 11 feet in 1985 which resulted in him being off work for four months; and · a possible herniated disc or a “popped” disc and a related hip injury suffered in 2002 when working as a foreman, for which he received chiropractic treatment; In report dated June 15, 2009, a physical medicine and rehabilitation specialist (physiatrist) stated: "As you know, he has had recurrent episodes over the years, with the most recent reported episode back in 2002. At that time, per your records, he had a L4-5 disc herniation on CT . . . . The CT and MRI studies from 2008 were reviewed. The CT shows evidence of a small L5-S1 disc herniation, whereas the MRI scan shows an L4-5 disc herniation . . . . In summary, this patient has a non-specific clinical presentation with no ominous or neurogenic features. There are no classic symptoms or physical signs to correlate with the L4-5 or L5-S1 lesions documented on imaging. While it is possible that the presence of a disc herniation at L4-5 in 2002 supports the notion that this lesion was present ever since, it is also possible that it may have healed and recurred. Either way, there is no way to specifically link an L4-5 disc herniation to his current presentation. His clinical presentation is somewhat clouded by his response to an intramuscular injection of corticosteroid. Typically, the effect of corticosteroid takes several hours to days, whereas he reported relief within 10 seconds. This either suggests a non-specific/placebo response to injection or an atypical response. Either way, the source of pain was not clarified by his injection." A WCB medical advisor made the following comments on June 23, 2009: "As documented in [physiatrist's name] June 15, 2009 correspondence, there is no way to specifically link the L4-5 disc herniation to [the worker's] current presentation. That said, [the worker] has reported low back symptoms in the environment of a possible recurrent L4-L5 disc herniation after a reasonable mechanism of injury. It is not possible to state with certainty at this time whether [the worker's] low back pain is related to the L4-L5 disc without a provocative discogram which includes injections to assess areas adjacent to the suspected disc. Should [the worker] report that his pain is reproduced with the control injections at sites other than the L4-L5 disc site, then [the worker's] reported low back pain would not likely be accounted for by the known L4-L5 disc herniation. I will send authorization for a provocative discogram." A report to the WCB dated July 27, 2009 from the worker`s family physician stated “This gentleman has never had any symptoms prior to July 29th the last five years as it relates to his low back problems.” He enclosed a report dated May 12, 2009 from the same orthopaedic surgeon who had reported to the WCB on May 7, 2009. He noted a small disc bulge on the CT scan at L5-S1, and a shallow L4-L5 central protrusion on the MRI. There was no significant disc considered at the L5-S1 level. He saw no need for either surgery or further chiropractic treatments. In a report dated September 21, 2009, the treating physiatrist noted that the worker underwent a three level disc stimulation study on August 20, 2009. He said the results were indeterminate since pain was provoked at all levels tested, including the suspected L4-5 level. In summary, the specialist found the worker's clinical presentation to be somewhat unclear. He noted that the worker's previous response to an intramuscular injection of corticosteroid was a non-specific/placebo response, or an atypical response, and questioned whether that may again be the case. If the disc pain did arise from L4-5, he noted that management options would include IDET, spinal fusion and disc replacement surgery. On October 13, 2009 the WCB medical advisor reviewed the physiatrist's report of September 21, 2009 and the August 20, 2009 three level discogram. He opined that it was unlikely that the worker's current reported low back symptoms were related to the L4-L5 annular tear or to the July 29, 2008 compensable injury. He noted that annular tears are a common occurrence in the worker’s cohort, and concluded that it was more likely that the worker's reported low back symptoms were related to the natural history of his pre-existing back condition that had necessitated ongoing chiropractic follow-up. In a decision dated October 19, 2009, primary adjudication advised the worker that wage loss benefits would be paid to October 26, 2009 inclusive as it was felt that his current reported low back symptoms were related to the natural history of his pre-existing back condition as opposed to his original compensable injury. On October 30, 2009, the worker appealed the decision to Review Office. In a further letter dated November 13, 2009, the family physician advised the WCB that the worker was attempting to return to work as it was his desire to do so. He said the worker suffered from chronic lumbago and neuralgic symptoms relating to the overuse of his back at work. The worker was referred to an orthopaedic surgeon for review. At the request of Review Office, a WCB orthopaedic consultant was asked to review the file and respond to specific questions related to the worker's claim. In a response dated January 20, 2010, the consultant concluded that the compensable injury was probably a strain of the lumbar spine causing non-specific low back pain and radiating pain to the right lower limb. In his opinion the worker's current symptoms were probably caused by a combination of the non-specific low back pain and by degenerative lumbar disc disease, including an annular tear and small disc protrusion at the L4-5 level. He commented that a single site of pain generation at the L4-5 disc level was not probable, based on current medical evidence that the protrusion was small and no nerve root compression was demonstrated. He found no objective medical evidence to demonstrate that the compensable injury caused aggravation of the pre-existing degenerative condition. However, the low back pain had reportedly continued without resolution from the time of the compensable injury, and so he suggested the issue might be resolved by a pending report from an orthopaedic spine specialist. In a decision dated January 26, 2010, Review Office determined that the worker was entitled to wage loss benefits beyond October 26, 2009. Review Office indicated that it found sufficient medical evidence on file to support that on a balance or probabilities, there was a causal relationship between the worker's current difficulties and the compensable injury. It noted that the worker's continued eligibility for wage loss benefits would be reviewed by primary adjudication when the orthopaedic surgeon's report of January 12, 2010 and the MRI of January 16, 2010 was on file. The MRI scan report of the lumbar spine dated January 16, 2010 demonstrated minor degenerative disc desiccation at L5-S1, and to a lesser extent at L4-L5. It also noted “a small annular tear posterocentrally at L4-L5. Tiny posterior disc bulge at L5-S1 without significant central foraminal stenosis or disc herniation." In a report to the family physician dated January 26, 2010, the orthopaedic surgeon referred to the same MRI scan which he reported as showing a “large” annulus tear at L4-5 that he indicated had not changed much from a previous MRI. He further noted that the L5-S1 level showed a “small central disc herniation but some collapse of the posterior annulus and also a chronic disc narrowing at L5-S1.” He advised that surgery would proceed for an L4-5 anterior discectomy and pro-disk replacement. It would be determined interoperatively whether arthroplasty was suitable at the L5-S1 level. On February 17, 2010, the file was reviewed by the WCB orthopaedic consultant who made the following findings: "[The treating orthopaedic surgeon], in his letter dated 26 Jan 2010, described the MRI as showing a large annulus tear at L4-5 and a small central disc herniation at L5-S1. In contrast, the radiologist's report of the same MRI indicated a small annular tear of L4-5 with mild diffuse disc bulging, and mild diffuse disc bulging at L5-S1 level. A haemangioma was noted in the body of L2 vertebra. The radiologist did not describe disc herniation. [The treating orthopaedic surgeon] has proposed disc arthroplasty at L4-5 and disc arthroplasty or fusion at L5-S1. He noted that the long term prognosis for arthroplasty is somewhat unknown, a statement that is supported by the medical literature. It is apparent that [the treating orthopaedic surgeon] considers the disc disease at both levels to be the cause of symptoms. It is more probable that the degenerative disease of the lumbar spine is the cause of the symptoms, and the degenerative disease affects facetal joints as well as intervertebral discs, and it is reasonable to predict that the proposed surgery will not permanently improve the condition with respect to comfort and function. It would appear that the proposed surgery is directed at pre-existing degenerative lumbar disc disease. The surgery is not related to the CI [compensable injury] which was a strain of the lumbar spine." In a letter to the orthopaedic surgeon on February 18, 2010 the WCB orthopaedic consultant stated that “The injury that occurred in July 29, 2008, was a low back strain causing non-specific low back pain. It is considered that the proposed surgery for L4-5 disc arthroplasty and L5-S1 disc arthroplasty, or alternatively fusion at L5-S1 is related to the pre-existing degenerative lumbar disease.” In a decision dated February 23, 2010, the worker was advised by primary adjudication that the WCB was unable to relate the surgery and his current symptoms to the workplace accident and that wage loss benefits would be paid to February 26, 2010 inclusive. The worker disagreed with the decision and an appeal was filed with Review Office. On September 8, 2010, Review Office confirmed that the worker was not entitled to wage loss benefits beyond February 27, 2010. Review Office was of the opinion that the evidence on file which included the diagnosis of a lumbar strain, the diagnostic test results, the opinion of the WCB orthopaedic consultant and the time that had passed, did not support a causal relationship between the worker's current difficulties and the compensable injury of July 29, 2008. On October 1, 2010, the worker appealed the decision made by Review Office to the Appeal Commission and a hearing was arranged. A May 27, 2010 operative report was submitted which showed that the worker underwent an anterior discectomy and prodisc replacement at L4-5 and L5-S1. In a report to the family physician dated December 20, 2010, the orthopaedic surgeon reported that the worker’s symptoms had greatly improved following his double level arthroplasty at L4-5 and L5-S1. He still had some complaints of pain in his right hip and in the upper part of his spine, but had a good range of motion in his back.
Reasons
The worker attended at the hearing before this panel, and responded fully and completely to questions from the panel in the course of the hearing. No one appeared on behalf of the employer.
Applicable Legislation
The worker is employed by a federal government agency or department and his claim is therefore adjudicated under the Government Employees Compensation Act (GECA). Under the GECA, an employee who suffers a personal injury by an accident arising out of and in the course of employment is entitled to compensation. The GECA defines accident as including “a willful and an intentional act, not being the act of the employee, and a fortuitous event occasioned by a physical or natural cause.”
Pursuant to subsection 4(2)(a) of the GECA, a federal government employee in Manitoba is to receive compensation at the same rate and under the same conditions as a worker covered under The Workers Compensation Act (the WCA).
The Appeal Commission and its panels are bound by the WCA, regulations and policies of the Board of Directors.
Section 39 of the WCA provides that where an injury to a worker results in a loss of earning capacity, wage loss benefits are payable until the loss of earning capacity ends.
Where that loss of earning capacity is caused in part by a compensable accident and in part by a non-compensable pre-existing condition, or the relationship between them, WCB Policy 44.10.20.10 (the Policy) requires the WCB to accept responsibility for the full injurious result of the accident.
The Policy provides in part:
(b) Where a worker has:
1) recovered from the workplace accident to the point that it is no longer contributing to a material degree, to a loss of earning capacity, and
2) the pre-existing condition has not been enhanced as a result of an accident arising out of and in the course of the employment, and
3) the pre-existing condition is not a compensable condition, the loss of earning capacity is not the responsibility of the WCB and benefits will not be paid.
The panel is satisfied that the above noted provision of the WCA and the Policy are applicable to cases under the GECA.
Worker’s Position
The worker argued that the injury that he sustained on July 28, 2008 led to chronic dessication of the L4-L5 and the L5-S1 disc spaces with chronic annulus rupture, and that the injury ultimately necessitated his surgery on May 27, 2010. In his view his benefits should be reinstated to the date of his recovery from surgery which took approximately six months post-operatively.
Analysis
For the worker to be successful we must be satisfied that the compensable injury or the compensable injury in concert with the worker’s pre-existing injury contributed to a material degree to his increased loss of earning capacity after February 26, 2010. We are unable to make that finding. After having reviewed all of the evidence before us, we find on a balance of probabilities that the worker had recovered from the effects of his workplace injury by February 26, 2010, and that his continuing lower back symptoms were related to a pre-existing condition, and not his compensable injury. We make this finding on the basis of the mechanism of injury, the medical evidence subsequent to the July 29, 2008 injury and a review of the worker’s extensive medical history.
Neither the CT Scan of August 18, 2008 nor the September 24, 2008 MRI demonstrate a significant disc injury. We have placed considerable weight on the opinions of the WCB medical advisors who considered those results. On October 14, 2008 a medical advisor noted that the multilevel disc changes on the CT scan were generally consistent with degenerative disc disease, and that the mechanism of the injury would not have caused the annular tear. That opinion was supported by the February 24, 2009 opinion of another WCB medical advisor who concluded that the compensable injury neither aggravated the pre-existing degenerative lumbar spine changes nor prolonged the duration of the worker’s symptoms. In a subsequent report of April 29, 2009 he commented: “As such, the anular tear reported at L4-L5 seen on the September 23, 2008 L/S spine MRI is equally likely to have been pre-existing related to a prior injury as related to the July 29, 2008 CI, and may not in fact, in spite of its presence, be the pain generator in [the worker’s] case." On January 10, 2010 the WCB orthopaedic consultant thought that a single site of pain generation at the L4-5 disc level was not probable, based on current medical evidence that the protrusion was small and no nerve root compression was demonstrated.
We think it significant that the worker had an extensive history of work and non-work related injuries and suffered from low back pain over a 23 year period as evidenced by both his medical records and his prior WCB claims. The WCB requested and obtained copies of the worker’s medical chart information for treatment provided to the worker by his family physician. A chart note dated October 16, 2002 refers to the worker having “chronic back pain 4 years. Fall from wall 14-15 years ago. Presently going to chiro 1/week with NSAIDS but looking for more permanent cure and no ongoing meds.” In a letter on the same file dated October 18, 2002 his physician reported the worker as having “long standing low back pain since the fall after a high wall about 14 years ago. At that time he had no acute fracture but did suffer a disc protrusion. His pain has been ongoing, a few years ago we did manage to settle his symptoms with anti-inflammatories but his symptoms do persist in spite of that.” He reported a recent CT scan which showed a small central disc herniation of L4-L5. A 2002 CT scan on file also showed that the L5-S1 was unremarkable. An earlier scan on April 9, 2001 reported no disc narrowing and normal SI joints. A February 16, 2001 report from the worker’s physiotherapist advised that the worker had received physiotherapy for “low back and right posterior hip pain that has been episodic in nature for the past 4-5 years. History of a fall 15 years ago causing disc protrusion caused problems for a year, but settled for some time.”
In a report dated October 15, 2008 the worker’s chiropractor provided a detailed assessment of his treatment of the worker commencing in August 2004. At that time he reportedly complained of intense low back pain caused by moving furniture in his home. He reported to the chiropractor that he had a history of low back pain which he related to his employment as an exterminator that required him to drive for long hours in a truck. He reported that his pain was aggravated by lifting, sitting and driving. He had been told by a medical doctor that he had degenerative disc disease in his low back. He was diagnosed at that time by his chiropractor with an acute left sacroiliac injury and irritation to his L5, S1 lumbar facet joints. The worker reattended the chiropractor on multiple occasions throughout the period from August 2004 to May 2008 complaining of low back pain.
It is evident that the worker had sustained injuries on a number of occasions and sought treatment for lower back symptoms for more than two decades. Yet in a letter to the WCB dated October 30, 2009 appealing from the termination of his benefits, the worker minimized his medical history significantly:
Although I had a back problem in the past (85-88), your answer to my problem was go see a chiropractor and you ultimately started me seeing chiropractors.
The back injury was caused by heavy lifting on a daily basis. Fridges, stoves, freezers, wood, furniture, branches, filing cabinets etc. Since 2002 and including 1 visit to [the chiropractor’s] office, I have been to the chiropractor`s office 30 times with a few for a shoulder injury. So in the past seven years, 84 months, roughly 27 visits were recorded over that period. That works out to just about 4 visits a year according to my calculation.
That history is not consistent with either the worker’s advice to the WCB medical advisor on February 24, 2009 that “on average that since 1985, he has seen his chiropractor three times per month for maintenance therapy”, or the worker’s WCB claims history. A review of the worker’s former WCB claims files discloses that in fact the worker’s medical history extended well after the period from 1985 to 1988 and that he had sustained a number of injuries prior to July 29, 2008.
WCB records confirm that on July 22, 1985 the worker injured his lower back when he hit a rock while shoveling gravel. He was diagnosed with multiple lumbo/sacral sprain/strain and treated with chiropractic adjustments and traction between July 24 and August 13, 1985. On October 3, 1988 he sustained an injury to his lower back and was off work for two weeks with pain in his back and legs. He was seen in 1989 by a neurologist for “low back pain which radiates into both anterior thighs . . . present since October 1988 when he was pulling electrical cables at work and he felt a sudden pain in his back.” Although he was treated by a chiropractor the pain increased and he stopped working on March 13, 1989. In the same report the neurologist refers to “a previous work related injury in 1984. At that time he had back pain and was off work for four months. His pains continued till about August 1988 and he claims that his pains were completely gone by the time of the October 1988 injury.” Between November 10, 1988 and April 6, 1989 he attended on a chiropractor for treatment on 27 occasions. The worker also sustained an injury on March 15, 2007 when he slipped and fell on his driveway. He complained of intense low back pain and thoracic spine pain, and was diagnosed with an acute low back strain. Although there does not appear to be a WCB file pertaining to a fall from a wall in approximately 1984, there is consistent reporting of such an occurrence both in the medical records and in the worker’s own evidence before the panel.
We are not persuaded by the opinion of the worker’s orthopaedic surgeon rendered December 20, 2010 that the injury sustained in 2008 led to chronic desiccation of the L4-5 and L5-S1 disc spaces with a chronic annulus rupture. It is not consistent with the worker’s medical history, the opinions from the WCB medical advisors or from other treating physicians. In a report dated May 7, 2009 an orthopaedic surgeon consulted by the worker’s physician noted that electrodiagnostic tests did not show a significant disc protrusion, and that an MRI showed no significant nerve root impingement or a disc protrusion. The physical medicine and rehabilitation specialist reported on June 15, 2009 that “Either way, there is no way to specifically link an L4-5 disc herniation to his current presentation.” While there is disagreement between the worker’s orthopaedic surgeon and the WCB medical advisor with respect to the size of the anular tear we note that the January 26, 2010 MRI refers only to a “small annular tear”. In any event we accept the opinion of the WCB medical advisor of October 14, 2008 that the anular tear would not have been caused by the mechanism of injury.
While the worker sustained a strain on July 29, 2008, having considered all of the evidence we find it more probable than not that the worker’s symptoms beyond February 26, 2010 were attributable to a pre-existing condition and not to his compensable injury of a lumbar strain. We find no basis upon which to include that his pre-existing condition was enhanced by the compensable injury. As the worker's ongoing back complaints as of February 26, 2010 are not causally related to the worker's 2008 compensable injury, there is no entitlement to wage loss benefits beyond that date.
The worker’s appeal is therefore dismissed.
Panel Members
K. Dangerfield, Presiding OfficerA. Finkel, Commissioner
G. Ogonowski, Commissioner
Recording Secretary, B. Kosc
K. Dangerfield - Presiding Officer
Signed at Winnipeg this 27th day of April, 2011