A 50-year-old nurse presented with suboccipital pain, numbness in the hands and fingers, and gait instability worsening for the past several years. She had bilateral brisk reflexes, positive Romberg’s sign, and numbness in C7 dermatomes bilaterally. An MRI showed evidence of significant canal stenosis from C3-7, for which she underwent cervical laminoplasty C3-6. At her two-week follow up, she reported significant improvement in her symptoms and returned to work in about four weeks.
Spinal stenosis, a very common neurosurgical condition, can be associated with spondylosis, ligamentous hypertrophy, and disc osteophyte complexes. Stenosis often presents as myelopathy (compression on the spinal cord) or radiculopathy (compression on the nerve root).
Cervical stenosis causes spinal cord compression, which presents as myelopathy (brisk reflexes, gait instability, loss of hand dexterity) or radiculopathy (radiating pain, shoulder pain, numbness, paresthesia) or as a combination. Interscapular pain is a very common feature of C4 or C5 nerve root involvement. Lumbar stenosis often presents as neurogenic claudication (pain in the legs while walking relieved by leaning forward). Paracentral and foraminal stenosis often affect a single nerve root resulting in a radiculopathy. Weakness is usually later in onset and can be only seen after prolonged standing or walking. Thoracic stenosis is quite uncommon and can present with features of myelopathy.
The diagnosis of spinal stenosis is confirmed with an MRI. For example, the average normal AP diameter of the cervical canal is 17 mm; a value of 10 to 13 is a relative stenosis, while less than 10 mm is absolute stenosis. Additionally, flexion extension X-rays of the cervical of lumbar spine can also find dynamic instability causing symptoms.
Various surgical treatment options for cervical stenosis include anterior or posterior approaches. The posterior approaches include laminectomy alone, laminectomy with fusion, foraminotomy, or cervical laminoplasty. Older patients or patients with a focal stenosis can be considered for laminectomy alone. Laminectomy with fusion is preferred in patients who have a higher chance of developing postoperative kyphosis. With a laminoplasty, the cervical canal is expanded while keeping the posterior elements (ligaments, lamina, spinous process) intact. Laminoplasty preserves most of the movements and reduces occurrence of degenerative changes at the adjacent levels as seen with a fusion. An anterior surgery is often considered with a predominant anterior compression and can be either a discectomy with fusion, disc replacement, or corpectomy (removal of vertebral body).
Lumbar stenosis usually requires a laminectomy and foraminotomy to free the nerve roots. When there is gross hypertrophy of the facets and stenosis of the lateral part of the neural foramen, a complete facetectomy would be required which destabilizes the spine and thus requires a fusion of the adjacent segments. Spondylolisthesis or dynamic instability on flexion/extension films can also be an indication for fusion.
Thoughtful clinical decision making is required when evaluating a mild or asymptomatic patient with cervical stenosis. I usually consider the degree of stenosis, age, associated medical morbidities, and lifestyle, and then hold an extensive discussion with the patient and family. A significant consideration is the risk of developing a spinal cord injury from a minor neck injury. With underlying spinal stenosis, a whiplash injury or fall may result in permanent injury. I distinctly recollect one of my patients with cervical stenosis who was rightfully cautious about surgery who then developed a central cord syndrome after a slip and fall. He became quadriparetic for several months and then recovered with residual deficits after surgical decompression.
A properly chosen procedure in an indicated patient usually has a high success rate for patient satisfaction. Most patients with spinal stenosis feel immediate improvement after a surgery when adequate decompression is done. I recollect one of my patients telling me few hours after the lumbar decompressive surgery, “Doc, I think I have a new pair of legs!”