Spinal Stenosis

Author: Dr Sibel Demir-Deviren University of California San Francisco 2008-07-19

What is Spinal Stenosis? 

Spinal stenosis is defined as narrowing of the spinal canal (the canal in the center of the spine), lateral recess (the narrowing of the tunnels where the nerve roots exit the central spinal canal), or intervertebral foramina (holes in the vertebrae which nerve roots exit). It can occur at any age and is typically due to the degeneration and enlargement of the facet joints (small joints between upper and lower vertebrae), the protrusion or herniation of the intervertebral discs and/or ligamentum flavum hypertrophy (a strong ligament that connects the vertebrae together). The narrowing of the canals puts pressure on the neural elements of the spine, including the spinal cord and nerve roots. Pressure on the upper part of the spine (neck area) usually produces pain, numbness, tingling or weakness in the shoulders, or arms. Pressure on the lower part of the spine (low back area) usually causes similar symptoms in the legs.

Who Gets Spinal Stenosis?   

The chance of developing spinal stenosis increases in the fifth decade of life and occurs at a rate of 1.7-1.8% in the general population. It may also be seen in younger people who are born with a narrow spinal canal or after a trauma. Spinal stenosis occurs equally in both males and females.

What Causes Spinal Stenosis?   

Spinal stenosis is classified according to both anatomic location and cause of the narrowing. The major types of stenosis, based on the location of the narrowing in the spine, are central stenosis, lateral recess stenosis, and intervertebral foraminal stenosis. This narrowing can occur in any region of the spine, but typically affects the cervical (neck) or lumbar (low back) regions.  

Central stenosis is the narrowing of the spinal canal itself. Anything that causes the spinal canal to be narrowed can cause central stenosis. The most common causes of central canal narrowing include: disc space collapse and concurrent folding of the ligamentum flavum into the canal space, vertebral disc herniation, spondylolisthesis (forward slippage of one vertebra on top of another), enlargement of the facet joints, and degenerative cysts of the facet joints.  

Lateral recess stenosis is the narrowing of the tunnels where the nerve roots exit the central spinal canal. This is also caused by enlargement of the facet joints or disc herniation.  

Foraminal stenosis is narrowing of the hole where the individual nerve roots exit to the spine. As the disc height diminishes, facet joints enlarge which result in reduction in the foraminal volume. The most common place for cervical foraminal stenosis is at the fourth, fifth, and sixth cervical vertebrae. In lumbar spine, the fifth lumbar roots are compressed more frequently (75%), and the fourth (15%), third (5.3%) and second (%4) occur less often.  

The causes of spinal stenosis may be congenital (present from birth), be acquired, or include features of both. Congenital stenosis can be a normal variant or be associated with dwarfism. This type of stenosis usually results in a canal that does not develop normally with regard to size and shape. It is quite rare, and occurs in approximately 9% of cases. These patients typically seek treatment between the ages of 30 and 40. Acquired spinal stenosis is stenosis in which the spinal canal and vertebrae are developmentally normal, but, overtime, develop narrowed portions. This narrowing is nearly always the result of acquired conditions such as: degenerative/arthritic changes in the spine, spondylolisthesis (when a vertebra shifts out of place), disc herniation, fractures, infection, tumors, or systemic bone diseases such as Paget's disease. Patients with acquired spinal stenosis typically seek treatment in their 50s and 60s.

Lumbar (Low Back) Spinal Stenosis

Approximately 1.2 million Americans have back and leg pain that can be attributed to lumbar spinal stenosis. Lumbar spinal stenosis is the most common reason for adult lumbar spine surgery in adults older than 65. The most common place for spinal stenosis to occur in the lumbar spine is at the fourth and fifth lumbar vertebrae (L4-L5) or the third and fourth lumbar vertebrae (L3-L4).

What Are the Symptoms of Lumbar (Low Back) Spinal Stenosis?  

Most patients seek medical treatment for spinal stenosis due to pain or neurologic symptoms. Generally, the symptoms of spinal stenosis occur gradually. Low back pain is present in 65-95% of patients and is exacerbated by walking, standing, and bad weather. Although low back pain presents earlier, the “classic” symptom of lumbar spinal stenosis is leg pain. Eighty to 90% of patients with symptomatic lumbar stenosis report leg pain.  

Spinal stenosis generally causes intermittent radiculopathy or neurogenic claudication. Radiculopathy is a term that can describe a variety of uncomfortable sensations, including of a feeling of heaviness, cramping, burning, weakness, or pins and needles radiating down the back, buttocks, thighs, and legs due to the compression or irritation of the nerve roots. These symptoms are bilateral (occur on both sides) in 40-50% of the patients, but are not necessarily symmetric. The pain gets worse by an upright posture. Most patients adopt a bending forward posture and frequently lean on a shopping cart, walls, or a cane. Bending forward temporarily increases the spinal canal size and decreases compression of nerves. Neurogenic claudication is a term used to describe the pain, often cramplike, and weakness that occurs in the legs of patients with walking. This pain is alleviated when the patient leans forward. Downhill walking is worse because it prevents patients from leaning forward. The distance required to cause symptoms or make symptoms worse is typically less than 100 meters, but it varies somewhat on a daily basis. Dysfunction in the urinary system has been reported in 12% of patients with long-standing spinal stenosis. This dysfunction may manifest as recurrent urinary infections, frequency, and incontinence, more rarely as urinary retention.  

The most common symptoms in patients with spinal stenosis are low back pain (95%), neurogenic claudication (91%), leg pain 80%), weakness (33%), and urinary system symptoms (12%). The severity of symptoms is not directly correlated with the amount of stenosis present.

How is Lumbar Spinal Stenosis Diagnosed?     

1) Medical history: All patients with symptoms of lumbar spinal stenosis require careful history to assess the severity of the symptoms and the impact the symptoms have on the patient’s daily activities, as well as to identify other clinical disorders that can cause patients to experience similar symptoms. The conditions that can have similar symptoms to spinal stenosis include: degenerative disc disease, facet arthropathy, spondylolisthesis, spondylolysis (a cracked vertebra), disc herniations, discogenic pain, sacroiliac joint dysfunction, myofascial pain (pain between the muscle and fascia), hip arthropathy (joint disease), polyneuropathy, and vascular claudication. Because of the overlap of symptoms among these various diseases, a thorough work-up of the patient must be performed.

2) Physical examination: Despite severe symptoms, patients with spinal stenosis have few physical findings. The neurologic examination is usually normal. When there is a weakness in the muscles, it is usually mild and typically affects the muscles innervated (supplied) by the L5 and S1 nerve roots. Changes in the sensation of skin are more common in an L4 or L5 distribution. Asymmetric reflexes at the knee or ankle are more common in patients with central spinal stenosis. Pathologic reflexes such as the Babinski reflex (where scratching the sole of the foot can cause fanning of toes with the big toe extending upwards) and clonus (when forced flexion of the ankle can cause a series of involuntary foot movements) are uncommon and their detection should warrant a workup for concurrent cervical or thoracic stenosis. The physician also performs nerve tension signs such as straight leg raise test (performed by having the patient lie or sit on a bed and raise their leg).  

3) Imaging Studies: Radiographic studies that correlate with the physical examination play an important part in determining if a patient has spinal stenosis. However, caution should be used when examining imaging studies because it has been shown that a larger percentage of patients with stenosis on radiographs are asymptomatic. Common types of imaging that may be used include: x-ray, computed tomography (CT) scans, magnetic resonance imaging (MRI), and myelography. X-rays can provide a lot of information about the possible causes of spinal stenosis. Disc degeneration, facet enlargement, sliding of the vertebrae, and the development of bone spurs can all be seen on x-rays. X-rays are also used to evaluate spinal alignment and to check for other bony abnormalities such as tumor, or fractures. MRI is the most common imaging study used to check for the presence of spinal stenosis. MRI affords both bone and soft tissue details and allows nerve root impingement to be well visualized. CT is a useful, cost effective tool used to diagnose spinal stenosis. However, CT without the combined use of myelography (the use of contrast dye) is not recommended for the usual evaluation of stenosis. CT myelography scans also allow the neural structures to be visualized and provides a good view of the central spinal canal as well as the lateral recesses and foraminal tunnels. These spaces are areas of the vertebra that often become stenotic.  

4) Other tests: Other tests that are clinically useful include nerve conduction studies and electromyography (EMG). These types of studies help the physician to determine if the radicular symptoms a patient is experiencing are caused by true radiculopathy or by other types of nerve problems.

What Are the Treatments for Lumbar Spinal Canal Stenosis?  

Spinal stenosis can be treated either non-surgically or surgically.  

1) Nonsurgical Treatment: Non-surgical treatments for spinal stenosis do not seek to “cure” the stenosis, but rather to alleviate symptoms caused by the stenosis. Non-surgical treatment goals are pain relief and improvement of daily function; the treatment is generally very successful. Studies have shown that 63-67% of patients who underwent non-surgical treatment reported “good to excellent” response to non-surgical treatments at their two-year follow-up.  

In the patient with acute pain, the treatment should begin with activity restriction. A 48 hour period of complete rest is the maximum for any patient with acute pain. Excessive bed rest is associated with loss of strength, flexibility, and aerobic fitness which only becomes more pronounced with time. Medications are also given to decrease the pain. The initial medication recommended is acetaminophen (Tylenol) because of its excellent safety profile. However, the patient must be cautioned against taking excessive doses (greater than 4000 mg/day) because it may lead to liver complications. Non-steroidal anti-inflammatory drugs (NSAIDs) (e.g., ibuprofen, naproxen, diclofenac) are preferred in patients who can tolerate these medications. Gastrointestinal side effects are the most common. If the patient ends up taking recommended dose of a NSAID regularly everyday, liver and kidney functions tests should be done regularly every couple months to prevent any injury to liver or kidneys. In those patients in whom gastrointestinal problems are concern, celecoxib (Celebrex) is the choice of NSAID. If the patient has paraspinal muscle spasm, muscle relaxants are also recommended for a short period of time. For more severe pain, narcotics are only for short term usage. Other medications that have proven to be successful in the treatment of nerve pain are also used in patients with leg pain. The most commonly used medications for nerve pain include amitriptyline (Elavil), gabapentin (Neurontin), pregabalin (Lyrica) and duloxetine (Cymbalta).  

Physical therapy modalities may be of use in the acute or chronic stage of pain; to decrease the pain before the therapeutic exercises, some use ice packs or heat depending on which is more comfortable.  

Lumbar pelvic traction in its various forms has been employed with variable degrees of success in the management of low back pain and spinal stenosis. Therapeutic efficacy of lumbar traction remains controversial.  

It has been consistently shown that therapeutic exercises are effective. The goal of strengthening is to decrease the extension force on the lumbar spine and increase core muscle strength, cardiovascular fitness, and flexibility of leg muscles while decreasing excess weight or obesity. A basic exercise program should be individually planned and tailored to the patient’s disability. If the patient is unable to do any floor exercises, pool therapy is beneficial. The exercise therapy shouldn’t increase patient’s pain. The inability of the patient to perform these exercises because of lack of motivation may often indicate that the patient is not a good surgical candidate who will not follow through with the postoperative rehabilitation.  

In patients who show slowly progressive disease or for whom surgical treatment is contraindicated, lumbar epidural corticosteroid injections are helpful. Epidural corticosteroid injections are used in patients who do not get enough relief from the above therapies or in patients who are limited in their activities of daily living and can not exercise because of pain.  

Other common non-medication based treatments include: massage therapy, TENS (transcutaneous electrical nerve stimulation), orthoses (bracing), and alternative medicine (acupuncture, spinal manipulation, relaxation therapy, hypnosis, and magnet therapy). Based on the studies, therapeutic efficacy of these modalities remains controversial. 

2) Surgical Treatment: If non-surgical treatment of spinal stenosis does not improve the symptoms within eight to12 weeks – or if a patient develops cauda equine syndrome (a rare disorder affecting the bundle of nerve roots at the lumbar end of the spine) or progressive neurologic deficits – it is appropriate to consider surgical treatment. Surgical treatment has been shown to provide better short term outcomes, but long term results of non-surgical and surgical treatment are very similar. The surgical treatment for lumbar spinal stenosis is a procedure called a decompression. During a decompression, the surgeon will remove bone and ligaments around the area that is stenotic. This allows the compressed or impinged nerves to have more room.   

There are different kinds of decompressions that can be performed, depending on the area of the spine that is stenotic or narrowed. For central stenosis, a procedure called a laminectomy is performed to relieve the stenosis. If a patient has lateral recess stenosis or foraminal stenosis a laminectomy or foraminotomy may be performed. Because lateral recess stenosis and foraminal stenosis can occur on either the right or left side of the vertebra, if only one side of the vertebra is affected, then the procedure need only be performed on that side.  

Cervical (Neck) Spinal Stenosis

Spinal stenosis of the cervical spine has causes similar to lumbar spinal stenosis and can occur in the same area of the vertebra: central canal, lateral recess, or intervertebral foramen. The most common place for spinal stenosis to occur in the cervical spine is at the fourth, fifth, and sixth cervical vertebrae.

What Are the Symptoms of Cervical (Neck) Spinal Stenosis?  

The most common symptoms of cervical spinal stenosis are radiculopathy or myelopathy. Radiculopathy is a symptom usually caused by lateral recess or foraminal stenosis. Patients describe sharp pain, tingling or burning sensation in the area supplied by the cervical nerve root or roots. Patients typically have severe pain and arm pain that precludes them from getting into a comfortable position. The most common symptoms and signs in patients with cervical radiculopathy are arm pain (99%), sensory deficits (85%), neck pain (79%), reflex deficits (71%), weakness (68%), scapular pain (52%), and headache (9%). Myelopathy is a set of symptoms caused by compression of the spinal cord itself. The symptoms of cervical myelopathy include a deterioration of fine motor skills, intermittent shooting pain into the extremities (especially when their head is bent down), inability to walk quickly, heavy feeling in the legs, arm pain, loss of balance, and bowel and bladder dysfunction.

How is Cervical Spinal Stenosis Diagnosed?  

1) Medical History: In order to determine if cervical spinal stenosis is causing a patient’s symptoms, a thorough history must be undertaken.  

2) Physical Examination: The physician will check patients’ gait, balance (Romberg test), cervical spine range of motion, skin sensation, muscle strength, reflexes, and pathologic reflexes. The patient’s symptoms are usually aggravated by extension and lateral rotation of the head to the side of the pain, known as the Spurling test. When the patient flexes and extends the neck, it may produce a feeling of electric shock, known as Lhermitte’s sign. For patients with severe cervical spinal stenosis, physicians should check whether the patient has any signs of cervical myelopathy; these are known as long tract signs (because myelopathy affects the nerve tracts that run inside the spinal cord known as the long tracts). Long tract signs include hyperreflexia (over-active reflexes), pathologic reflexes in the lower extremities that include Babinski reflex and clonus (as described above), Hoffman reflex in upper extremities (flicking the middle finger may cause the thumb and index finger to involuntarily flex), and spasticity (increased muscle tone). Myelopathic gait appears somewhat broad based with disruption of smooth, rhythmic, normal function of gait. The first change in the gait is difficulty with turns.  

3) Imaging Studies: Similar imaging studies to those run for lumbar spinal stenosis are run for cervical spinal stenosis. X-ray, CT scan, CT myelography, and MRIs are all commonly done in cases where cervical spinal stenosis is suspected.

What Are the Treatments for Cervical Spinal Canal Stenosis?

Spinal stenosis can be treated either non-surgically or surgically. 

1) Nonsurgical Treatments: Non-surgical treatment is typically limited to patients with radiculopathy. Non-surgical treatments goals and options are similar to lumbar spinal canal stenosis with few exceptions.  

It has been shown that cervical traction is effective in patients with arm pain.

Patients with severe cervical spinal stenosis and with cervical myelopathy should avoid neck extension (bending backward) activities. For patients with severe cervical spinal stenosis, range of motion exercises should be avoided during physical therapy.   

There is not any hard evidence of clinical effectiveness of manipulative therapy on the cervical spine. Moreover, manipulation of cervical spine carries significantly more risk than manipulation of the lumbar spine because of the greater mobility and the presence of spinal cord in the cervical region. Absolute contraindications for spinal manipulation include vertebral fracture or dislocation, infection, malignancy, spondylolisthesis, myelopathy, cauda equine syndrome, Marfan’s and Ehlers-Danlos syndromes (genetic disorders that affect connective tissue), osteomalacia (bone softening) and osteoporosis (a disease in which bones become more fragile), spondyloarthropathies, severe diabetes mellitus, anticoagulation therapy, and objective signs of spinal nerve root compression. 

2) Surgical Treatment: If non-surgical treatment of spinal stenosis does not improve radicular symptoms or if a patient exhibits frank myelopathy, it is appropriate to consider surgical treatment.  The surgical treatment for cervical spinal stenosis is a procedure called a decompression.  During a decompression, the surgeon will remove bone and ligaments around the area that is stenotic.  This allows the compressed or impinged nerves to have more room.

There are different kinds of decompressions that can be performed, depending on the area of the spine that is stenotic or narrowed.  A decompression can be done with several different approaches, including anterior (front), posterior (back) or combined.  Laminectomy and laminoplasty are the most common posterior surgical techniques used to treat cervical spinal stenosis.  During a laminectomy, the surgeon removes part of the back of the vertebra in order to accommodate the compressed nerves.  A laminoplasty is a similar procedure; however, it removes less bone from the vertebra.  Anterior discectomy (with or without fusion of the vertebrae) is a common procedure used to decompress single level cervical stenosis. Anterior corpectomy with structural bone grafting and stabilization is a common treatment when multiple vertebral levels are stenotic.

What Are the Major Risks of Surgery for both Lumbar and Cervical Spinal Stenosis?

Decompression, with or without fusion, like any other surgical procedure, is not without risks.  Possible complications include but are not limited to:  persistent pain, infection, neurologic injury, prominent implant under the skin after the surgery, instrument breaking or pulling out of the bone in which it has been implanted, urinary tract infection, stroke, pneumonia, deep vein thrombosis (clotting), pseudoarthrosis (vertebrae do not fuse together), and further progression of the stenosis.  In general, however, complications are uncommon. 

More Information

Web Resources 

American Academy of Orthopaedic Surgeons

North American Spine Society

Scoliosis Research Society