What is a spinal stenosis?
Spinal stenosis is a term used to described narrowing of the spinal canal that houses the neural elements. Narrowing is caused by wear and tear changes resulting in formation of bone spurs and overgrowth of soft tissue. Central stenosis refers to narrowing of the main hollow passage which contains the spinal cord in the cervical and thoracic segments or nerve fibers of the cauda equina in the lumbar segments. Foraminal stenosis is the narrowing of the exiting pathway for the segmental nerve roots. The image below is an illustration of a cross-section of a healthy spine. There is adequate space in the spinal canal where the spinal cord to resides.
Cross-section of a healthy vertebrae
The opposite can be seen in the next image. The spinal canal is narrowed due to the thickening of the ligaments, and deterioration of the intervertebral disc.
Narrowed spinal canal
WHAT ARE THE SYMPTOMS OF STENOSIS?
The symptoms of stenosis vary greatly depending on the location and degree of narrowing and whether the spinal cord or nerve roots are being affected.
Symptomatic spinal stenosis is most commonly encountered in the the lower lumbar spine. Central stenosis of the lumbar spine can cause aching back pain spreading to your legs (neurogenic claudication). Symptoms are typically worse with standing or working and are alleviated by sitting down. Patient with lumbar spinal stenosis can also experience "pins and needle" sensations in their buttocks, calves, and legs. Sometimes patients just feel that their legs are "weak".
Other areas in the lumbar spine that can be stenotic include the lateral recess, and foramina. These pathologies typically only impinge one single nerve and will present as radiating pain from the spine to the area supplied by the nerve (radiculopathy).
The pain can be relieved with with movements involving flexion at the hip or sitting.
Radicular pain and ways to reduce pain
Stenosis of the cervical spine can cause compression of the spinal cord, the patient may develop signs and symptoms of myelopathy. You may experience pain that feels like an intense electric shock from your neck to your arms or down your lower back to your legs. Sometimes the pain is accompanied by numbness or weakness. In severe cases you may experience loss of hand dexterity, difficulty walking, gait imbalance, multiple falls and/or loss of bladder or bowel control. Cervical foramina stenosis may also be present and can cause radiating pains from the neck to the arm or hand.
*If you experience extreme leg weakness or difficulty controlling bladder or bowel function, you should seek medical help immediately.
WHAT ARE THE CAUSES OF SPINAL STENOSIS?
Spinal stenosis can occur due to a combination of factors, some of which include but are not limited to arthritis, congenital stenosis, disc herniations, degeneration and collapsing of the intervertebral disc, buckling or overgrowth of surrounding ligaments, calcification of ligaments, overgrowth of surrounding bony structures, and trauma. Genetics, smoking, aging and several occupational and recreational activities may lead to early disc degeneration that results in spinal stenosis.
HOW IS A DIAGNOSIS MADE?
A health care provider will take a history of your symptoms and perform a physical exam. The history and physical will help determine the source of the pain and test for muscle weakness or numbness. If the findings from the history and physical are consistent and suggest a disc herniation, a magnetic resonance imaging (MRI) study is obtained to confirm the diagnosis. In certain circumstances your doctor may order additional studies such as: an X-ray, computer topography (CT) scan, or electromyography (EMG) study.
WHAT TREATMENTS ARE AVAILABLE?
The first line of treatment for a disc herniation is conservative, non-surgical therapy, which includes but is not limited to; pain management with medication, physical therapy, epidural steroid injections (ESI) and nerve blocks or alternative therapies. Non-surgical therapy treatments will result in significant improvement and return to normal activity in roughly 80% of people in about 6 weeks. If you don’t respond to conservative treatment, your doctor may recommend surgery. Surgery may also be recommended if you have signs of nerve damage, such as weakness or loss of feeling or problems with your bladder function.
WHAT SURGICAL TREATMENTS ARE AVAILABLE?
Surgical treatment of a herniated disc will vary due to multiple contributing factors that your surgeon considers before making a surgical plan. Some of these factors include but are not limited to your symptoms, the location and size of the herniation, your overall health, as well as your spine health and spinal alignment. Surgery for disc herniations can be performed in the cervical, thoracic or lumbar spine. Most disc herniation surgeries only require a decompression of the compressed neural structures, however some require a decompression and fusion procedure. These surgeries can be performed using an open traditional surgical technique, minimally invasive technique or a full-endoscopic technique.