The condition — known by the unwieldy name of cervical spondylotic myelopathy, or CSM — is estimated to affect about 20 per cent of Canadians, usually after age 50. About 10 per cent of those patients require surgery to alleviate progressively worsening symptoms.
"Cervical spondylotic myelopathy is the commonest cause of spinal cord impairment in the world, and it's a complication of arthritis," said Dr. Michael Fehlings, a neurosurgeon at Toronto Western Hospital, who led the study.
"If patients have arthritis, they may very well have this in the neck and it's very, very common," he said. "People will typically present with pain in the neck, but they may not necessarily be aware that they're at risk of developing paralysis."
CSM, which can occur in anyone but is particularly prevalent in people of Asian and South Asian descent, results from the narrowing of the spinal canal, creating pressure on the spinal cord. The condition can cause neck stiffness, arm pain and numbness in the hands.
In an estimated 30 to 50 per cent of cases, the condition gets progressively worse. Left untreated, CSM can affect the limbs, impairing the ability to walk or perform everyday tasks and eventually leading to paralysis.
"It can affect bladder and bowel function, it causes terrible pain, people lose their hand function, they lose their independence, they lose the ability to walk, they can develop all sorts of terrible complications," said Fehlings, medical director of the hospital's Krembil Neuroscience Centre.
Henry Wang's symptoms began in early 2009, with numbness in the pinky finger of his left hand and his baby toe. The tingling and needle-like pain then spread up his left side to the neck; his hand started cramping and his legs began to feel heavy, impeding his ability to jog or play recreational sports.
"The symptoms certainly spread very quickly," Wang, 53, said from his home in Pickering, Ont., just east of Toronto.
His family doctor and a specialist were baffled by what was causing his symptoms, even after an MRI scan.
"It was definitely not an enjoyable time," said the computer consultant. "Daily activities were becoming difficult and the numbing sensation I was experiencing made it hard to concentrate."
"Because I wasn't sure what was happening, I gave up any activity where falling could be a risk. This condition was really affecting my quality of life."
Wang was eventually diagnosed with CSM, caused in his case by a hardening of ligaments that had narrowed his spinal canal and were pressing on his spinal cord.
In late 2009, with 60 per cent compression of his cord, Wang underwent a decompression operation performed by Fehlings, who was heading the 12-centre North American clinical trial to assess the effectiveness of the surgery.
"What was amazing about it was right after surgery ... I didn't feel any symptoms," said Wang. He was back at work in two weeks, although physicians warned him that over time some symptoms could recur due to the extent of damage to his spinal cord.
That's why, said Fehlings, it's important that doctors and the public become more aware of CSM and seek treatment sooner rather than later.
"Time is spine," he said. "And once you lose it, you lose it."
Based on the study published Wednesday in the Journal of Bone and Joint Surgery, which evaluated post-surgical function and quality of life for 278 patients with mild, moderate or severe CSM, Fehlings said spinal decompression is a safe and effective means of alleviating symptoms.
The study showed the surgery improved health quality of life scores, often dramatically, comparable to those of cataract surgery or hip replacement.
"So in other words, it's a game-changing degree of improvement," he said, but stressed that the surgery has the greatest impact for patients in the earlier, milder stages of CSM.
"The more severe you are at the outset, the less optimal the degree of recovery, although all patients do show evidence of recovery."
Yet Fehlings said cervical spondylotic myelopathy is not on the public's radar nor that of many health providers.
Indeed, CSM has too often been misdiagnosed as carpal tunnel syndrome when a patient has numbness and clumsiness in both hands, even though the repetitive strain injury typically occurs only in one hand.
"It's important for the public and primary-care practitioners to know this because (CSM) is a very common and reversible cause of spinal cord impairment," he said.
"It's a preventable cause of paralysis, so instead of people ending up in a nursing home and unemployed, they continue to be productive citizens, continue to be independent. It makes the difference between somebody ending up in a wheelchair ... and somebody enjoying a highly productive life with excellent quality of life."
Wang is relieved to know the surgery has halted the steady progression to paralysis he was facing, a prospect he called of "very high concern."
"There was no other option for me but to have the surgery. If I hadn't had it, I don't know what state I would be in right now."