Spinal stenosis is a condition in which the spinal canal, which carries the spinal cord and spinal nerves, get narrowed. This causes various symptoms due to pressure on nerve tissue. Some patients have a narrow spinal canal since birth, which becomes symptomatic later on with minimal further stenosis caused by degeneration. This condition is called Congenital/ Developmental Spinal Canal Stenosis. However, in majority of the patients, spinal stenosis is the result of chronic degeneration of tissues in and around the spinal canal.
A herniated disc, arthritic facet joints, hypertrophied ligamentum flavum, all contributes in narrowing the spinal canal. Also, as disc height reduces due to progressive degeneration, the openings on the side, called neural foramen, gets constricted leading to pressure on exiting spinal nerves (foraminal stenosis). Similar to a disc herniation, poor posture, heavy laborious activities, obesity, injury to spine can all contribute to early degeneration of the spinal tissues causing spinal stenosis. Spinal stenosis can also be secondary to other major pathologies of the spine, e.g. spinal tumors, spinal infections, spinal tuberculosis, spondylolisthesis, spinal fractures etc.
In Lumbar Canal Stenosis, patients usually have Claudication, wherein patient is comfortable in resting, sitting, standing position; however, after walking a particular distance, they feel neurological symptoms in legs (Neurological Claudication) in the form of pain, tingling numbness, loss of sensation and weakness in legs. This can sometimes mimic symptoms from loss of blood supply to legs (Vascular Claudication). Though a careful history, physical examination and certain tests can differentiate one from the other. Spinal stenosis in thoracic spine might cause all the symptoms of lumbar canal stenosis with additional loss of balance and spasticity in both legs (Thoracic Myelopathy).
A Cervical Spinal Canal Stenosis will cause symptoms primarily in upper limbs. Along with typical symptoms of nerve pressure, patient will also experience loss of dexterity of hand functions and weakness of hand grip. Also, there will be significant spasticity in upper and lower extremities in severe cases (Cervical Myelopathy). Bladder-bowel can get affected in spinal stenosis at any level indicating severe dysfunction of spinal cord. Recovery in these advance cases is usually slow and incomplete, even after surgical intervention.
- History and physical examination,
- MRI Scan: Main diagnostic tool which will show level and severity of pressure on spinal cord,
- X-rays: to rule out bone abnormalities,
- CT Scan: A CT might be required to assess bone structure in detail. Also, C is recommended when MRI cannot be done (patients with heart pacemaker, ear cochlear implants, certain stainless steel orthopaedic implants),
- EMG-NCV: In cases where there is mismatch between MRI picture and patients symptoms. Also when other nerve related abnormalities need to be ruled out, e.g. diabetes, carpal tunnel syndrome, primary neuropathies and myopathies,
- Doppler test: To rule out vascular claudication.
- Blood Tests: Various blood tests might be required to rule out vitamin deficiency (B12), infection, and tumors.
- Other tests: Specific tests to confirm/ rule out infection and tumors might be required, if these conditions are suspected (CT guided biopsy, Histopathology, Culture and Sensitivity etc.)
Spinal stenosis is an irreversible pathology. However, patients symptoms may not correlate with degree of stenosis. Some patients have minimal symptoms even with significant spinal canal stenosis and others are severely symptomatic even with mild stenosis. Treatment for spinal stenosis is usually based on severity of patients symptoms and response to given treatment.
- Medical treatment: An initial course of pain killer medicines along with local application of pain relieving ointments are used to soothe pain. Other medications are given to make nerve more resistant to painful stimuli to reduce nerve related symptoms (radiculopathy, tingling, numbness). A spinal brace is given to eliminate excessive motion at painful spinal segment and to provide support to spine. Some amount of activity restriction is advisable to prevent worsening of symptoms. Physiotherapy helps in strengthening the back/ neck muscles and reduces muscle spasm.
- Epidural Injection: Similar to disc herniation, epidural injection can be tried in patients with spinal stenosis also for symptomatic relief. A small amount of anaesthetic medication and steroid are injected next to the spinal cord to reduce inflammation. This reduces nerve related symptoms. Epidural injection doesn’t reverse spinal stenosis and help patient buy time before they decide for a definitive treatment. Usually patients get about 4-6 months of significant pain relief; however this might last shorter or longer also. If symptoms recur, injection can be repeated 2-3 times. Epidural injections cannot be given to patients with uncontrolled diabetes and patients on blood-thinner therapy for heart conditions.
- Surgical Decompression of Spinal Cord: Patients who have severe symptoms to start with or those who don’t respond to above treatment with significant restriction of their day to day activities, usually need removal of pressure from spinal cord. This can be done in various ways-
- Micro-Lumbar Decompression: A Minimally Invasive Spine Surgery using a microscope is usually sufficient for majority of the patient. MIS spine surgery has the advantage of minimal post-operative pain, early hospital discharge and faster recovery.
- Endoscopic Spine Surgery: In selected cases, an endoscopic spinal canal decompression can be done. Some of these cases can be done under local anaesthesia also, which is useful for older patient with multiple medical problems where a full anaesthesia can cause side effects.
- Laminectomy: In patients with severe spinal canal stenosis, developmental stenosis and multi-level pathology, a formal laminectomy might be the best solution for relief of current symptoms and prevention of recurrence.
In patients with associated significant back pain/ neck pain, severe disc degeneration (spondylosis), slip of vertebra over other (spondylolisthesis), spine fracture (spondylolysis) and spine deformity (scoliosis/ kyphosis), a spine fusion/ instrumentation might also be advised by your spine doctor along with the removal of slipped disc.