In the context of the normal aging process, the spine presents progressively degenerative lesions in the vertebrae (bones), intervertebral discs, muscles and joints that anatomically compose the spine.
All these degenerative changes lead to spinal stenosis.
A stenosis is often the final result of several degenerative diseases, such as osteoarthritis (spinal arthropathy) and/or degenerative spondylolisthesis and/or disc herniation.
In the case of stenosis, the spinal nerves coming out of the intervertebral foramens cause symptoms at the lower extremities. Spinal stenosis is the most common spinal condition in people over 60 years of age with spinal arthropathy, while in younger patients disc herniation is the most common one.
SYMPTOMS
The typical symptom is lower extremity pain and lameness (neurogenic lameness) which can significantly reduce the patient’s level of activity. Patients with lumbar spine stenosis do not report symptoms at rest, but they cannot walk for long distances with no leg pain, which immediately subsides as they rest again.
For most patients the symptoms vary widely, with periods of recession and exacerbation.
The severity and duration of symptoms varies from patient to patient and essentially dictates treatment (conservative or surgical). They usually develop gradually over the years (over 50 years) and include:
- Lower extremity pain (sciatica)
- Walking lameness and pain
- Weakness and numbness that reflects on the buttocks and legs
- As the vertebral stenosis gets worse, the symptoms become more severe, causing major problems in the patients’ daily lives. It is estimated that in the United States 400,000 people suffer from back pain and sciatica due to lumbar spine stenosis.
CAUSES
The causes of vertebral stenosis in the lumbar spine are directly linked to aging. The facet joints tend to deform and become hypertrophic after gradual dehydration and loss of the intervertebral disc’s height (discitis), causing compressive effects on the spinal cord and spinal roots. In addition, the ligamentum flavum is thickened due to inflammation and, in turn, it also puts pressure on the nerve roots.
Rarely, lumbar spine stenosis may occur in young people with curvature in the spinal foramens or after spinal cord injury.
In general, patients do not report any particular problems when seated. Finally, it is important to note that lumbar spine stenosis does not cause serious injury and therefore the final decision for surgery is the patient’s (discitis).
DIAGNOSIS
When a patient experiences typical symptoms of lumbar stenosis (leg pain with or without back pain that worsens during walking), a definitive diagnosis is made by using imaging examinations (e.g. MRI or CT). Physical examination alone cannot provide a definitive diagnosis.
There are three main types of stenosis:
- Oblique stenosis. It is the most common type of stenosis and occurs when a nerve root that has exited the spinal canal is compressed by an edematous disc, a disc herniation or osteophytes.
- Central stenosis. It can lead to compression of the cauda in the lower part of the spinal cord.
- Foraminal stenosis. In this case the spinal root is compressed in the intervertebral foramen mainly due to osteophytes.
TREATMENT
CONSERVATIVE TREATMENT
Typically, the initial treatment of vertebral stenosis in the lumbar spine involves:
Modification of daily activities: Patients usually feel more comfortable when they bend slightly forward. For example, many patients are relieved when they lean on a walking cane or a stroller.
Exercise: Recommended as part of treatment for most patients with vertebral stenosis. A targeted exercise program under the guidance of an experienced physiotherapist or orthopedist can prevent further progressive degeneration and ensure patient comfort. For example, a static bicycle can be considered a beneficial treatment option because patients stand slightly bent forward during exercise.
Non-steroidal Anti-Inflammatory Drugs (NSAIDs): Since inflammation is a common component of vertebral stenosis, NSAIDs such as ibuprofen or COX-2 inhibitors can alleviate symptoms.
Epidural Steroid Injection: These injections can be administered in outpatient clinics; the procedure lasts 15-30 minutes and requires no hospitalization. The doctor guides a special needle to the epidural space. Once the needle is inserted in the correct position, the steroid is injected slowly. Epidural injections use steroids as a powerful anti-inflammatory agent and often include a rapid-acting local anesthetic agent for temporary pain relief.
Surgical treatment
Surgery for lumbar spine stenosis should be considered on the basis of the patient’s inability to participate in their daily activities and the effort to relieve chronic pain. For most patients, surgical treatment of lumbar spine stenosis is associated with lifestyle choices:
- If patients have had to quit many of their daily activities, they may need to consider the possibility of surgery.
- If patients continue to maintain a high level of functionality with no particular symptoms, there is no need to subject them to the additional risk of surgery.
The time for surgery does not modify the final clinical outcome.
In general, patients who have delayed for years the surgical treatment have the same results as those who underwent immediate surgery.
LAMINECTOMY
Elective surgery for lumbar spine stenosis is laminectomy. The modern techniques used allow for smaller incisions. However, the goals remain the same: The compression-inducing bone (osteophytes) is removed along with soft tissues, such as the hypertrophic ligamentum flavum. Laminectomy is used at the level of the lumbar and cervical spine.
In patients with concomitant spinal instability or with such a degree of spinal stenosis that will require significant decompression causing instability, laminectomy is accompanied by spinal fusion with supporting materials. Laminectomy is essentially an open decompression surgery and is performed to relieve the pain caused by vertebral stenosis.
Lumbar laminectomy differs from microdiscectomy in that the incision and detachment of the tissues is greater.
Initially, and after the level of operation has been precisely determined, a midline incision of about 8-10 cm is performed. An incision and detachment of the dorsal muscles (erector spinae) follows on both sides on multiple levels.
After approaching the vertebrae, the surgeon gently removes part of the lamina bilaterally (laminectomy), exposing the nerve roots, as well as part of the hypertrophic ligamentum flavum.
Finally, a very small piece of the facet joints is cut to provide more space to the nerve roots.
Postoperatively, patients are hospitalized for one to two days, and the mobility that the patient regains depends on his preoperative condition and age. Patients are encouraged to walk straight after laminectomy for lumbar stenosis. However, it is recommended to avoid excessive flexion and extension of the torso for six weeks to avoid re-opening of the surgical trauma.
The success rate after laminectomy is very high and is generally admitted to relieve patients’ pain. After laminectomy, about 70 to 80% of patients report a significant improvement in their daily activities and a reduction in the pain associated with spinal stenosis.
LAMINOTOMY – FORAMINOTOMY
If the removal of the lamina is partial, the surgical procedure is called laminotomy. In the attempt to decompress the spinal stenosis, the foramina may also be released (Foraminotomy). In the case of stenosis on one side and one level, the decompression can be performed by the method of minimally invasive decompression (Micro-decompression).