CERVICAL SPINAL CANAL STENOSIS
Spinal canal stenosis is the narrowing of the spinal canal (the passageway that houses the spinal cord) located just behind the vertebrae, which squeezes the spinal cord (at various levels) as well as the nerve roots. Patients with this problem may have weakness, tingling, and numbness in their arms and/or hands. In more serious cases, loss of function and gait disturbance may be observed.
If the spinal cord compression is severe, patients may have symptoms such as difficulty or inability to do certain activities that require fine motor skills (inability to button up shirts or tie shoelaces). In cases where the disease also affects the legs, patients may become incapable of walking unaided or may have a spastic gait as well as urinary and fecal incontinence.
Increased reflexes on the arms and legs, loss of sense and strength in the hands and legs may be detected during examinations of patients. In addition, a group of abnormal findings called pathological reflexes in the hands and feet can be seen. Several or all of the mentioned findings can be found in a patient.
Deteriorations in the form of attacks in the cervical canal are seen more frequently. Patients feel comfortable or have few symptoms during the interim periods of such attacks. A very slow progression is observed in 25% of patients, while on the other hand, a sudden deterioration is seen in 2% of patients.
Alignment and radiological anatomical structures of the cervical vertebrae, diameter of the canals from where the nerve roots extend, degenerative changes, whether there are any vertebral slippage and the anatomical relationship of the cervical vertebrae and the head region are evaluated with a directed graph. Computed tomography of the cervical vertebrae or their computed tomography 3D reconstruction provides more detailed information about these. 3-D images also help defining (in a visual sense) the inner structure of spinal cord canal in more detail. Computerized cervical spinal cord tomography is also required for performing measurements intended for determining the extent to which the fixating systems such as screws and plates (sometimes need be used in surgical operations) will be used. However, the gold standard diagnostic method in recent years is to examine the region with magnetic resonance imaging. Magnetic resonance imaging (MRI) is an indispensable diagnostic method for evaluating the disc structures located in the intervertebral distances, the facet joints connecting the vertebrae to one another, the connective structures keeping the vertebrae together, the spinal cord as well as the anatomical condition of the nerve roots extending from it. The spinal cord injury (myelopathy) seen during this examination can be considered to be a sign that the disease has progressed to a considerable extent.
Electrophysiological examinations are electromyography (EMG) and somatosensory evoked potential (SSEP). EMG is used to evaluate peripheral nerves while SSEP is used to evaluate spinal canal pressure. Electrophysiological examinations are very useful diagnostic methods especially in the differential diagnosis of cervical spinal canal stenosis from other the similar diseases.
Injuries caused compression due to spinal canal stenosis, a condition called myelopathy, is one of the most important factors for surgical decision making. If there is no myelopathy, and if the weakness and loss of sensation in the arms, hands and legs are not at serious levels, nonsurgical procedures (physiotherapy, pharmacotherapy etc.) can be helpful for resolving the patient’s problem partly.
Surgical operations are intended to eliminate disc hernias that cause pressure on the spinal cord; osteophyte formation; calcification of the strong connective tissue passing between the vertebrae; enlargement of the yellow ligament (becomes apparent) at the back of the spinal cord; degenerative inward enlargement of the facet joints that connect the vertebrae to one another; and spinal canal stenosis that is a rare condition in which one vertebra slides over the vertebra below it. It is called decompression surgery, i.e. a surgical procedure intended for eliminating the compression.
Removal of the compression is possible with surgical operations performed with an anterior or posterior approach. However, the decision on which of these approaches would be appropriate will be taken by the neurosurgeon after the required examinations. In cases of compression caused by only the disc, the operation used to be performed on the disc, without intervening the two vertebrae adjacent to that disc. Sometimes the structure causing frontal pressure may be the calcification of a very strong ligament extending from the back of the vertebrae. In such a case, the vertebral body/bodies as well as the disk tissues are removed along the affected section. They are placed by bone graft materials or cage-type implants serving as vertebrae. Then, a fusion is performed from anterior side by using plates and screws.
In surgical operations performed with a posterior approach, the yellow ligament creating the compression and the lamina constituting the back of the spine may need to be completely removed. In such a case, it would be appropriate to perform a fixation (fusion) operation to strengthen the spine, by placing screws as well as rods that hold them in position. The spinal canal can also be expanded with ‘laminoplasty’, a surgical procedure performed with the help of an implant material inserted in the space after the surgical removal of a part of the lamina.