The Appeal CommissionThe Workers Compensation Act of Manitoba

Introduction

This appeal deals with the causal relationship between the worker’s low back symptoms and his March 13, 2005 workplace accident.

Background

On March 13, 2005 the worker was in the course of his regular duties when he slipped on ice and fell. The mechanism of injury has been explained by the worker on multiple occasions:

• His March 14, 2005 accident report notes that he slipped and landed on his upper back and hit his head; 98% of his weight landed onto his shoulder blades.

• A May 12, 2005 WCB memorandum notes that the worker fell in a “C” shape with his head tucked.

• June 14, 2006 examination notes from a WCB medical advisor note that the worker slipped such that his feet went out in front of his body and above his head. As he realized that he was going to fall with considerable impact, he flexed his neck so as to avoid striking his head. He landed on his back with considerable impact and hit his head as well.

The worker was seen by several medical practitioners after his accident:

• A March 13, 2005 emergency report form notes that the worker complained of a stiff neck and upper back as well as a headache and neck pain. He was diagnosed with a muscular strain/contusion of the upper back.

• A March 15, 2005 report from the worker’s treating chiropractor notes that the worker injured his thoracic spine and there was clinical evidence of fixation at the T3-4 and T4-8.

At the hearing, the worker testified that after his accident he continued to experience a great deal of pain and stiffness in his neck and shoulders, though he missed very little work. He also had some stiffness in his lower back for which he sought chiropractic adjustments and did exercises. Toward the end of March, the stiffness developed more into pain and the chiropractic adjustments were no longer providing him with relief. His symptoms took a turn for the worse on about April 11, 2005 when he started having difficulties standing.

The evolution of the worker’s symptoms is recorded in several documents in the worker’s WCB file:

• An April 4, 2005 WCB memorandum to file notes that the worker returned to work on March 17, 2005 even though he was not feeling 100%. In the days preceding April 4, 2005 he felt something move out of place in his back and was uncomfortable ever since. He was not certain whether this was related to his workplace accident or not.

• An April 11, 2005 report from the treating chiropractor notes a new diagnosis of “thoraco-lumbar”. The report notes the worker’s complaints of chronic lumbar pain with right leg and thigh discomfort from weight bearing.

• An April 12, 2005 CT scan of the lumbar spine revealed mild annular disc prominence at L3-L4 and L4-L5.

• An April 22, 2005 progress report from the treating chiropractor notes yet another new diagnosis of L4 radiculopathy. The chiropractor noted the worker’s complaints of low back pain with difficulties with walking and standing up.

• A physiotherapy report dated April 28, 2005 listed the worker’s diagnosis as “discogenic low back pain”.

• A May 12, 2005 WCB memorandum to file notes that after returning to work, the worker had good and bad days since the accident and continued to seek chiropractic care as needed. On March 28, 2005 he was at work doing nothing out of the ordinary; he went for an adjustment after.

• June 14, 2006 examination notes from a WCB medical advisor note that immediately after his slip and fall the worker did not experience any leg symptoms. He continued to attend chiropractic care which seemed to alleviate the symptoms to some extent but the pain persisted. By the end of March 2005 he was experiencing pain in his mid-low back that felt like lightning bolt shots of pain and had difficulty standing and sitting as a result of the pain. He advised the WCB medical advisor that there was relative temporal continuity with his workplace accident. The low back pain persisted and on April 12, 2005 it had progressed to a severe “charley-horse” type of pain in his anterior right thigh which persisted until the end of June 2005.

• A June 18, 2005 MRI noted the following:

“At the L2-3 level there is desiccation of the intervertebral disc. There is mild right and left posterolateral disc protrusions with associated mild foraminal narrowing…

At the L3-4 level there is desiccation of the intervertebral disc. There is mild-to-moderate right posterolateral and lateral disc protrusion and associated anular tear. There is compression of the right L3 exiting nerve root with associated mild-to-moderate right foraminal narrowing. There is mild hypertrophy of the ligamentum flavum. Mild facet joint osteoarthritis is seen bilaterally.

At the L4-5 level there is a mild right lateral disc protrusion with no evidence of foraminal narrowing. Mild facet joint osteoarthritis is seen bilaterally…”

The radiologist interpreted the MRI as revealing degenerative disc disease at the L2-3, L3-4 and L4-5 levels.

The causal relationship between the worker’s March 13, 2005 workplace accident and his low back condition was explored by the WCB and commented on by several medical practitioners:

• On May 12, 2005, a WCB medical advisor commented that it was unclear how the worker’s low back complaints since early April 2005 related to the initial compensable injury of a thoracic sprain/strain.

• A May 12, 2005 WCB memorandum to file records a conversation between the case manager and the treating chiropractor. It notes that the treating chiropractor had treated the worker since the date of accident and on claims in the past. He felt the worker’s onset of low back pain was consistent with the mechanism of injury.

• The WCB medical advisor also spoke with the treating chiropractor. Her conversation is documented in a memorandum to file. She notes that the treating chiropractor thought that the worker’s low back complaints were related to the initial compensable incident. He stated the worker had initially reported thoracolumbar pain and was treated with manipulations. The worker had an increase in his pain with radicular features a few weeks later without any inciting or traumatic event. After this conversation, the medical advisor opined that there was a temporal relationship between the compensable injury and the radicular symptoms without any other reported accidents or incidents and that consequently, it was most likely that the worker’s current symptoms were related to the initial traumatic fall which occurred on March 13, 2005.

• Another WCB medical advisor reviewed the file on July 4, 2005 and commented on the causal relationship specifically with reference to the MRI results. He noted that the MRI showed both multilevel degeneration in the lumbosacral spine and an L3-4 disc herniation and right L3 radiculopathy. He did not think that the degeneration was related to the compensable injury but that there may have been an aggravation of this pre-existing condition. He did however think that the L3-4 disc herniation with right L3 radiculopathy could possibly be related to the compensable injury.

• On December 15, 2005, the treating chiropractor authored a report detailing his care, the progression of the worker’s symptoms and the causal link between the worker’s low back condition and his March 13, 2005 accident.

He noted that the worker saw him on March 15, 28 and 30, 2005 as well as on April 1, 4, and 18, 2005. On his first visit, the treating chiropractor noted mid-thoracic and lower thoracic discomfort. He also noted that the worker complained of numbness in the lower extremities on April 1, 2005, discomfort in his low back after sitting on the couch on April 4, 2005 and increasing stiffness after a 10 to 15 minute jog on April 10, 2005. It was his medical opinion that there was a causal relationship with the diagnosis of an L3 nerve root irritation as a result of a lateral disc protrusion to the right of the L3 disc to the March 13, 2005 compensable injury. He explained that the posture adopted by the worker during his fall would increase the mechanical factors at the thoracolumbar/upper lumbar spine. He clarified that the worker’s injury was not a lumbosacral injury but rather a thoracolumbar injury involving the third lumbar disc and slow onset of radicular symptoms with the L3 nerve root. He explained that an upper lumbar injury does not present with the same symptom picture as a typical lumbosacral disc injury, which would be discomfort in the leg particularly below the level of the knee. He added that it was not uncommon with a radicular injury to not lose the involved reflex until 2-4 weeks post injury or for nerve root irritation to become fully symptomatic.

The radicular symptoms reported by the worker approximately three weeks after the accident were therefore consistent with the presentation of a radicular disc type of injury. He noted the worker had no other reported traumatic type of events that occurred between March 13 and April 11, 2005 that would be of the extent to be a precipitating cause of the noted injury. The damage that was reported by the MRI would take a substantial force that in his opinion would fit with the fall the worker experienced on the day in question.

• Yet another WCB medical advisor reviewed the worker’s file on March 23, 2006 and commented that the compensable injury increasingly appeared to be an enhancement of the worker’s pre-existing condition.

• In a January 24, 2007 report, an occupational health doctor commented on the mechanics of the worker’s injury. He noted that the worker had fallen around the T7 level of his spine while the spine was flexed and the head was tucked. He felt that the hard landing on his upper back was not the principal cause of his injury. Rather he thought that with the impact on the pavement, the worker’s lower limbs and body would have continued to arc as the back and hops flexed, delivering a significant ballistic stretch to the long extensors attaching to the sacrum and hips, with the lumbosacral spine and hips ending in full flexion/hyperflexion, which resulted in significant compressive forces applied to the lumbar spinal elements. To his mind, this was the likely biomechanical cause of the right L3-4 annulus disruption.

Two orthopaedic specialists disagreed with these opinions on the causal link:

• A June 1, 2006 report from an orthopaedic specialist retained by the accident employer states:

“Given that [the worker’s] initial injury was very much limited to the upper back and neck area, it was relatively minor and he only missed one shift from work, he was able to return to work in full capacity involving the lifting of patients onto stretchers on several occasions, there was a significant gap in the chiropractic treatment between March 15 and 28, 2005 and there was no mention of a low back issue until April 12, 2005, I cannot really associate his initial injury of March 13, 2005 with his subsequent low back problem of almost a month later. There is no medical evidence establishing a relationship between his workplace accident and his low back symptoms a month later.”

• A September 5, 2006 report from an orthopaedic consultant to Review Office notes:

“There certainly would be immediate low back pain when a disc is injured/herniated. The onset of any associated radiculopathy due to nerve root involvement by a herniation can be delayed 2-3 weeks. The file does not indicate any immediate low back problems. The MRI reports multilevel [degenerative] disc disease including two disc herniations at L3-4 and L4-5 levels and [osteoarthritis]. In my opinion this was all pre-existing. Furthermore the reported disc herniation at L3-L4 would not encroach on the L3 root as it has already exited the spinal cord. It may however compress the L4 [nerve] root.”

He also opined that the worker’s lumbar complaints from the second week in April 2005 were not related to his March 13, 2005 compensable injury. He added that based on the historical record and the subsequent investigations, the worker’s lumbar complaints were due to multilevel degenerative disc disease and osteoarthritis.

Worker’s Position

The worker says that his low back condition of April 2005 is causally related to his March 13, 2005 compensable injury as it is consistent with his mechanism of injury.

Employer’s Position

The employer says that the worker’s low back condition of April 2005 is not causally related to his March 13, 2005 compensable injury as there is no credible evidence that the low back was injured at the time of the workplace accident or that the worker suffered low back symptoms immediately following the workplace accident.

Analysis

To accept the worker’s appeal we must find on a balance of probabilities that his low back condition is causally related to his March 13, 2005 workplace accident. Considering the worker’s biomechanics during his workplace accident and the progression of his low back symptoms, this panel is able to make that finding.

The evidence before us is that the worker slipped and fell on some ice while in the course of his duties. Though he reported landing on his upper back and hitting his head, the majority of the impact was to his upper back. At the hearing (and to WCB personnel and medical practitioners), the worker explained that he landed in this manner as his feet flew out from beneath him and went above his head, which he tucked to avoid a serious head injury. Despite the employer’s dispute as to this mechanism of injury, the panel accepts this evidence as it is consistent throughout the file.

The effect to the worker was back discomfort. This was reported initially as being to his upper back and neck which is consistent with the impact of his fall. Though the medical reports do not specifically report low back symptoms until April 2005, the treating chiropractor clarified later that the worker did complain of low back stiffness as of the first visit. At the hearing, the worker explained that he was receiving chiropractic adjustments in March for his low back which seemed to relieve his low back discomfort for approximately one week. The nature of these low back symptoms changed to include radicular symptoms in April 2005.

Though the employer disputed the accuracy of the treating chiropractor’s later clarifications as to the onset of his low back symptoms, the panel does not find any sufficient evidence that he erred or misrepresented this information. Indeed, the panel notes that the chiropractor relayed this information orally and in writing. It is also consistent with the fact that the worker did receive chiropractic adjustments to his low back in March 2005.