Why are my fingers numb? Part 4


NUMBNESS IN THE fingers is often due to nerve compression. This final segment on numbness discusses cervical spinal stenosis. Spinal stenosis in the neck has the potential to compress both the spinal cord and nerves exiting the spine that go to the upper extremity. Numbness in the hands, weakness in the arms and legs, and balance—all critical functions for life on two wheels— may be affected!

Stenosis means narrowing, and in the case of cervical spine stenosis the passageway for the spinal cord and the nerves that exit the spinal cord become smaller, compressing the nerve elements. There are special congenital anatomic features that may contribute to spinal stenosis, but the most common cause is age-related wear and tear in the spinal column in the neck, called degenerative disc disease. Because these changes occur slowly over time, cervical spinal stenosis is most commonly diagnosed in those over 60.

DEGENERATIVE DISC DISEASE begins relatively early in life. MRI scans of the spines of individuals without spine symptoms in their second, third, fourth, fifth and sixth decade of life show progressive degenerative change, which is a normal part of the aging process, including the following elements: narrowing and bulging of the disc toward the spinal cord; narrowing and a telescoping collapse of the facet joints; infolding of the ligamentum flavum; bone spur formation from the vertebral bodies and facets. In spinal stenosis, not only is the spinal cord compressed, but the nerves exiting the spine are also compressed, similar to a herniated disc. Symptoms of spinal stenosis can include stiffness and discomfort in the neck, upper back discomfort about the shoulder blades, deteriorating balance and dexterity, and weakness and numbness in the upper extremities. If the patient’s history and physical exam point toward spinal stenosis, the diagnosis is usually established with X-rays and an MRI scan.

TREATMENT OF SPINAL stenosis often begins with conditioning and therapy. Cervical traction may help. Injection therapies, such as steroid injections about the spinal cord or roots exiting the spinal cord, can be done. Surgical treatment is tailored to specific anatomic features. Some of these include the number of spine levels involved, the presence of instability between the vertebral bodies, the presence of osteoporosis, and the presence of any deformity of the normal spine curvature due to the degenerative disease. Treatment goals include opening the canal for the spinal cord and roots, as well as stabilizing the spine. This often includes a fusion, which, in some cases, is done from both the front and back. The prognosis after surgery for the spine often correlates with the amount of permanent damage to the spinal cord itself. The MRI is sometimes predictive of this and can reveal abnormalities of the cord itself that might limit recovery. In addition, loss of neck motion correlates with the number of spine levels fused.

WHETHER OR NOT the patient can safely return to riding after treatment of spinal stenosis will likely be related to the degree of loss of balance, upper extremity function loss, the number of levels fused, and the degree of osteoporosis of the bone. Modifying the riding activity may be advised and that discussion is not always well received, but we aim to return riders to their sport and the patients must make the choice for themselves. We’ve had senior motocross racers return to the track. We have also had patients with significant balance issues return to enjoyable cross-country touring on a motorcycle equipped with a sidecar. However, like recurrent head injuries, the reward of riding again must be compared with the risk of further injury.