What is Lumbar Spinal Stenosis?
Lumbar Spinal Stenosis (LSS) is a type of medical condition which is characterized by the narrowing of the spinal cord that effectively causes the medulla spinalis and the nerves located at the lumbar vertebra level to compress. LSS can develop as a congenital condition of varying degrees in the lumbar (lower back) and cervical (neck) region. It can also cause pain in the thighs, legs, feet and buttocks or cause loss of bladder and bowel control.
Lumbar Spinal Stenosis Causes
This condition occurs primarily due to spinal degeneration that commonly accompanies the process of aging. It can also be caused by various other factors such as osteoporosis and spinal disc herniation.
Picture 1 – Lumbar Spinal Stenosis
Although some individuals are born with small spinal canal, the majority of the cases of spinal stenosis develop due to certain factors that reduce the space within the spine. The various causes of spinal stenosis include:
Overgrowth of bone or bone spurs
Wearing and tearing of the spinal bones can lead to the development of bone spurs in the spinal canal. Deterioration of the cartilage around the joints leads to the formation of osteophytes. They may also develop due to Paget’s disease or arthritis.
There are several soft cushion-like structures that function as shock absorbers. They are present within the vertebrae and naturally have a tendency to dry out as a person ages. Cracking, rupturing, swelling or bulging of the exterior of the disk might allow a small portion of the inner soft material to get out and cause pressure on the medulla spinalis or the nerves. Although a herniated disk can be very painful, it does not always lead to the formation of a lumbar spinal stenosis.
The numerous tough cords that assist in binding the spinal bones together can grow thick and stiff over time. The structure of the ligamentum flavum might change to occupy more space within the spinal canal. These thickened ligaments can protrude into one’s spinal canal.
Enlarged facet joints
If the facet joints within the spine get enlarged, it may cause narrowing of spinal canal.
Tumors or abnormal growths can develop inside spinal cord, inside the membranes covering spinal cord or within the space between medulla spinalis and vertebrae.
Spondylolisthesis is the process which involves forward slippage of a vertebra over another within the spine. This might lead to narrowing of spinal canal and cause pinching of the various nerves.
Fractures or dislocation of a single or more vertebrae can be caused by car accidents or other major traumas. Displaced bone from spinal fracture might damage the inner contents of spinal canal. The swelling of the adjacent tissues right after a back surgery can also put pressure on the nerves or the spinal cord.
Lumbar Spinal Stenosis Risk Factors
The various risk factors that increase the chances of developing a degenerative lumbar spinal stenosis include:
- Paget’s disease
- Cushing’s syndrome
- Ankylosing spondylitis
- Degenerative osteoarthritis
- Congenital narrowing of spinal canal
Lumbar Spinal Stenosis Symptoms
The various symptoms and signs of this spinal condition are mentioned below:
Individuals having spinal stenosis might or might not experience back pain. The intensity of pain depends on the progression of the arthritic condition that has developed.
Sciatica or burning pain in legs or buttocks
The pressure caused on the spinal nerves can cause pain to the areas supplied by the nerves. The pain is usually an aching or a burning sensation. It generally starts around the buttocks and then gradually radiates down one’s legs. The pain down one’s legs is frequently referred to as sciatica.
Numbness or tingling sensation in legs or buttocks
With increasing pressure on the nerves, a sense of numbness and a tingling sensation frequently accompanies the burning pain. However, burning pain is not always followed by numbness and tingling in each and every patient.
“Foot drop” or weakness in legs
As nerve pressure reaches a critical point, weakness can develop in either or both the legs. Some patients will experience a foot drop, a feeling that one’s foot is slapping the ground while he or she is walking.
Less pain as one sits or leans forward
Patients may experience less pain while sitting or leaning forward as they expand the space that is available for nerves. On the other hand, standing up straight or walking may actually cause more pain.
The other symptoms that are caused by LSS include:
- Dull cramping
- Loss of sexual functions
- Stiffness in legs and thighs
- Loss of bowel and bladder control
- Loss of motor functions of the legs
Lumbar Spinal Stenosis Diagnosis
A doctor would first discuss the case of a patient and study his or her medical history. This will be followed by a detailed examination of the back. The doctor will then recommend conducting certain imaging tests which would include:
- CT myelogram
- Magnetic resonance imaging (MRI) scans
Lumbar Spinal Stenosis Differential Diagnosis
A number of arthritic and spinal conditions show signs and symptoms similar to that of LSS. The diagnostician needs to differentiate these conditions from spinal stenosis in order to settle on the optimum treatment method to manage this condition. The differential diagnoses for LSS includes conditions such as:
- Pott disease
- Spinal tumors
- Myofascial Pain
- Epidural abscess
- Rheumatoid arthritis
- Traumatic lumbar strain
- Mechanical low back pain
- Lumbar facet arthropathy
- Peripheral vascular disease
- Inflammatory arachnoiditis
- Large central disc herniation
- Lumbar compression fracture
- Lumbar degenerative disk disease
- Developmental or congenital scoliosis
- Diffused idiopathic skeletal hyperostosis
- Lumbar Spondylolisthesis and Spondylolysis
Lumbar Spinal Stenosis Treatment
The management of lumbar spinal canal stenosis is carried out by laminectomy and non-operative therapies. Not much information is available for the doctor to recommend specific non-surgical treatments. Conservative treatment consisting of medications, activity modification, physical therapies, home exercises and spinal injections can be carried out. The patients are normally advised to stay away from activities that might cause stress of the lower back area, particularly having the spine extended. The patient might also be subjected to a physical therapy program that allows core strengthening as well as aerobic conditioning.
Picture 2 – Lumbar Spinal Stenosis Image
Not much evidence is available for the effective treatment for LSS through medical intervention. Injecting non-nasal calcitonin might be helpful in bringing short-term pain relief. Pain may also be reduced temporarily by epidural blocks, although their long-term effectiveness is still in question. Cortisone injections can reduce swelling and pain, although they should not be used for more than 3 times in a year. Application of steroids does not necessarily improve the results of these injections. There is widespread debate and controversy surrounding the usage of the ESIs or epidural steroid injections. NSAIDs (non-steroidal anti-inflammatory drugs), opioid analgesics and muscle relaxants are frequently used to treat lower back pain, although substantial evidence as to their effectiveness is lacking and should only be used to a limited extent.
Lumbar traction might help to alleviate the symptoms of pain in some cases.
This is an effective method to reduce pain associated with lumbar stenosis. However, special care needs to be taken if the patient has disk herniation or osteoporosis as the manipulation of spine in these instances might cause worsening of the symptoms or lead to other injuries.
This therapeutic procedure can be helpful in reducing the pain in less severe forms of lumbar stenosis. Although the process is safe, its long-term effectiveness has not been proven successfully.
Surgery is commonly reserved for patients having a poor quality of life due to excessive pain and discomfort. Sufferers might have difficulty in walking or performing other movements, and it is especially in these circumstances that the doctor recommends surgery. There are 2 types of surgical procedures that can be conducted to treat LSS:
This involves removal of the bones, bone spurs, and the ligaments that cause compression of the nerves. It is also technically referred to as a decompression procedure. Laminectomy can be conducted as an open surgery in which a single, large incision is used to access the spine. It can also be done by an alternate, minimally invasive method that involves making several smaller incisions.
If the arthritis has advanced to cause spinal instability, spinal fusion is carried out. This involves combining decompression and stabilization methods. In this procedure, 2 or more vertebrae get permanently fused together. The bone graft used in the fusion of the vertebrae is taken from the hip or pelvis. Fusion minimizes motion between the vertebrae and prevents slippage from worsening once surgery is over. Rods and screws might be used to hold the spine of patients in proper place while the bones are being fused.
Lumbar Spinal Stenosis Prognosis
The condition of most individuals having mild to moderate signs and symptoms do not worsen over time. The outcome of LSS depends on several factors and may vary from one patient to another. Although many patients improve shortly after surgery, this improved state does not last long and somewhat decrease with time. Various factors present prior to the surgery can influence the post-surgical outcome. People suffering from scoliosis, depression and cardiovascular diseases generally do worse than individuals having more severe stenosis but otherwise have a better overall health.