Spine Concepts- Lumbar Spinal Stenosis
Lumbar spinal stenosis is the narrowing of the spinal canal and narrowing of the intervertebral foramen (nerve root canal). There are two types of lumbar spinal stenosis — central and lateral. Hypertrophy of the facet joints, hypertrophy of the ligamentum flavum, disc degeneration, or arthritis are all examples of conditions which constrict the nerve root canals, causing compression of the spinal nerves and sciatica. The patient will have back pain that is better with flexion, or leaning forward. The pain will be worse with extension of the back. Leaning forward increases the foramen size by about 12%. Leaning backwards reduces the foramen size by about 20%. A neurological exam is normal in about 50% of patients.
Central canal stenosis is responsible for giving neurogenic claudication. The patient may have leg pain, back pain, buttock pain, weakness, cramps of the calf, and a heavy sensation. The grocery car sign (flexion of the back) may also be present. The patient history is key for making the diagnosis of spinal stenosis. Lateral Recess Stenosis will give radicular symptoms and can occur in the nerve root canal. Neural foraminal stenosis occurs in the intervertebral foramen. The physician should look for other conditions such as: hip problems, metastatic tumors, or vascular conditions. Pulses should always be examined. Neurogenic claudication and vascular claudication may coexist. Walking is bad for both neurogenic and vascular claudication. Sitting will relieve the symptoms in both conditions. Stopping and standind still is good for the vascular claudication, but still causes symptoms for lumbar spinal stenosis. Using a stationary bicycle will relieve symptoms of lumbar spinal stenosis; however, it will aggravate the symptoms in vascular claudication. With vascular claudication, pain starts within the calf and leg. With neurogenic claudication, pain starts proximally and then spreads distally. It seems like postural changes of the spine will make the neurogenic claudication worse; however, this will not affect the vascular claudication. Vascular claudication will be affected by muscle movement or muscle function, such as walking or riding a bicycle. In neurogenic claudication, leaning over while riding the bicycle will relieve the symptoms in the same way as the shopping cart sign.
Treatment of spinal stenosis consists of operative treatment. For central canal stenosis, a decompression by laminectomy will be performed. Lateral recess stenosis will require a medial facetectomy. A fusion may be added for instability, or if more than 50% of the bilateral facets are removed. X-rays and MRIs should be observed for slips in the vertebrae. If a slip is found, a fusion should be done in addition to the laminectomy. The risk of pseudoarthrosis is increased 500% by smoking. Depression, as well as other comorbidities can affect the outcome. In two years, patients who are treated with surgery are better in pain and function than the patient who is treated conservatively. The most common reason for failed surgery is recurrence of the disease.
If a patient is found to have low back pain and a gait disturbance (hyperreflexia), then the patient may have an upper motor neuron lesion. Think of the cervical spine! The physician will want to order an MRI of the cervical spine after examining the patient. Cervical spine myelopathy should be remembered because lumbar stenosis does not give these findings! A patient with spinal stenosis, spondylolisthesis, or facet disease will have pain with extension of the lumbar spine. Pain with lumbar spine flexion will suggest a disc related disorder.
The Faber test is helpful in determining the presence of sacroiliac (SI) joint problems. The sacroiliac joint is one of the most neglected areas that may cause low back pain. The sacroiliac joint is always forgotten, unappreciated, and misunderstood as a possible source of low back pain. There are give categories of tests included in the Waddell’s sign:
· Simulation tests
· Tenderness tests
· Flip test
· Nonanatomic weakness and sensory findinns
· Overreaction- This is controversial and deals with patients who may be malingering or exaggerating their symptoms for the purpose of secondary gain.
The patient may have a Trendelenburg gait involvement due to the spine. A posterolateral L4-L5 disc herniation will affect the gluteus medius and gluteus minimus muscles. If the patient has a lumbar spine burst fracture, and the fracture is stable with no neurological deficit, the orthosis and surgery are equivalent to the clinical outcome. A patient with a burst fracture should be placed in the orthosis and ambulated. The absolute indication for emergency surgery is progression of neurological deficit with spinal canal compression. When you have a low lumbar burst fracture and a laminar fracture, you may have trapped nerve roots. There may also be a dural tear. Treatment will be in the form of a laminectomy, reduction, and fixation. As for seat belt lumbar spine injuries, the physician should also be aware of possible abdominal injuries and colon injuries in children.
Anterior surgery can cause retrograde ejaculation and it can be caused by surgery due to injury of the sympathetic. Injury to the parasympathetic may cause erectile dysfunction and usually does not occur due to anterior surgery because the parasympathetic is deep within the pelvis. This injury is common found from a fractured pelvis with urethral tears. The dominant contributing factor with intravertebral disc degeneration is genetics. The risk factors for the development of adjacent segment degeneration is laminectomy adjacent to the fusion. Adjacent segment disease can be slipped instability disc herniation, facet arthritis, or a fracture. 30% of lumbar fusion will develop adjacent segment degeneration 10 years after surgery. Some physicians believe that lumbar total disc replacement reduces the incidence of accelerated degeneration of the adjacent segment.
Thoracic spine disc problems usually occur in males. These issues are radicular pain that radiate to the ribs and anteriorly at the same level. These patients will have gait disturbance but a normal upper extremity examination. A lower extremity examination will show upper motor neuron findings (Clonus and Babinski). Plain x-rays should be ordered prior to an MRI (MRIs have a high false positive rate). Surgery is done if the patient has myelopathy; laminectomy is contraindicated.
Patients with low back pain and urethral discharge should be assessed for Reiter’s syndrome. HLA-B27 is positive in over 80% of cases. The sedimentation rate may be high. The physician should check for small joint arthralgia, Achilles tendonitis, or plantar fasciitis.
