Complex Spinal Surgery
Low Back Pain
Low back pain is the second most common reason for people to seek medical attention, and may be considered a nearly universal human condition. Up to 90% of people will experience low back pain at some point in their lives.
Although there are many causes of low back pain which can be effectively addressed by surgical intervention, a large proportion of low back pain has no precise identifiable anatomic cause, and is usually related to strain of the muscles and ligaments around the spine. This is called musculoskeletal or mechanical low back pain, and may commonly result from traumatic insult such as may occur with heavy lifting or falls.
The majority of low back pain, whatever its cause, will resolve spontaneously with several weeks of bed rest, where ambulation is limited to visits to the bathroom and eating, and strenuous activity is avoided. We advocate this initial approach for most types of back pain. However, if pain does not resolve after a trial of bed rest, or it is associated with leg pain, sensory changes, or leg weakness, further investigation and surgical consideration may be indicated. It is also important to realize that back pain may be a symptom of other serious disorders which would not seem related to the back, such as abdominal tumors or abdominal aneurysms. This is something which should always be considered if back pain is constant for prolonged periods or rapidly worsens, or if it is unrelated to physical activity or position.
In order to better understand the nature of low back pain, a brief description of spinal anatomy may be useful. The spinal column consists of 24 to 25 spinal bones, or vertebrae, which are arranged vertically and separated by intervertebral discs, which are thin, rounded soft tissue structures. At the lower end of the spinal column is the sacrum, a single bony structure which evolved from fusion of several vertebral bodies. The spinal column acts as a protective casing for the delicate spinal cord, which is the nervous system structure which carries information to and from the body. The spinal cord is surrounded on all sides by the bony structures of the spinal column. The spinal cord projects further into the body by paired nerve roots which exit either side of the spinal column through openings called foramina. In the low back region, called the lumbosacral spine, the spinal cord ends, but sends nerve roots further down the spinal canal to exit at each vertebral level. Several degenerative processes may occur in the spinal column, leading to impingement on nervous structures and pain.
There are several routine radiological exams which are employed to determine the cause of back pain. The most common exams include the MRI, or magnetic resonance, which demonstrates soft tissue such as disc and nerve roots with great clarity, and produces multidimensional views of the spine. The CT, or computerized tomography scan, is most useful for bony anatomy. The myelogram is a test in which a small needle is inserted into the spinal canal and dye is injected into the sac containing the spinal cord and nerve roots. By taking X-rays the flow of dye can be visualized, providing important information about nerve root compression. The CT myelogram, a combination of the CT scan and the myelogram, provides even more detailed information by clearer visualization of dye flow. These tests may demonstrate a herniated lumbar disc, spinal stenosis, and spondylolisthesis, as well as other conditions.
Lumbar Disc Herniation
Lumbar disc herniation is one of the more common surgically treatable conditions causing back pain. The intervertebral discs are composed of a soft inner pulp surrounded by a tough outer ring. With trauma or degenerative change in the disc, the central pulp may bulge outward through the ring and exert pressure on one or more nerve roots. Compression of a nerve root by a disc fragment causes radiculopathy, which may include weakness of muscles controlled by that nerve root, pain in the distribution of the root, or sensory changes such as numbness, tingling, or hypersensitivity in the same area. Back pain is often experienced in conjunction with these symptoms.
Sciatica is a term used to describe pain which occurs in the distribution of the sciatic nerve, a major nerve in the leg made up of several nerve roots in the lower spinal cord. Sciatica may occur with lumbar disc herniation, but may also be seen in certain other spinal disorders. The most common disc herniation syndromes cause shooting pain in the lateral or posterior aspect of the leg which may reach the foot and toes, or sometimes anterior thigh pain and groin pain. This pain may be associated with weakness of the quadriceps muscle, calf muscle, or a foot drop caused by anterior lower leg weakness. Pain caused by disc herniation will often resolve with bed rest, as described above, but if this pain does not resolve, or if muscle weakness is severe or progressive, surgery may be indicated. If the physical exam findings correlate well with radiographic findings, lumbar discectomy will usually provide relief of symptoms.
For a lumbar discectomy, a small (about one inch) vertical incision is made over the spine at the level of the herniation. The tissues are dissected so that the herniated disc is visualized, and any fragments compressing the nerve root are removed. This is usually done with a microscope so that tissue dissection is minimized. For most lumbar discectomies, the patient may be discharged home the day after surgery.
Another commonly encountered cause of low back pain is spinal stenosis. Spinal stenosis is a condition caused by arthritic degeneration of the spine, and is more common with advanced age. In this condition, the bones, joints, and ligaments which surround the nerve roots of the spinal cord become enlarged as a result of arthritis. In this manner, these structures compress one or several nerve roots, causing neurologic symptoms. These may include low back pain, leg pain, and leg numbness. Another characteristic symptom of lumbar stenosis is neurogenic claudication, meaning progressive leg muscle weakness with exercise. This is due to compression of nerve roots which control muscle function, with compression preventing the nerve root from adequately stimulating leg muscles under the increased physiologic demand which occurs during exercise. These symptoms may also improve with bed rest, but if this fails a decompressive lumbar laminectomy will usually provide relief. The aim of this procedure is to decompress the nerve roots by removing portions of hypertrophied bone, joints, and ligaments. The incision is similar to that used in a lumbar laminectomy, although it may be slightly longer depending on the number of levels involved. Patients may be up and walking the day after surgery, and may possibly be discharged home that day.
Low back pain may also be caused by spondylolisthesis, which is defined as a slippage of one vertebral body anteriorly in relation to one below. Usually this occurs where the lumbar and sacral spines meet. This slippage may be caused by degenerative changes in the spine, congenital defects of the spine, or trauma. The result is pain caused by nerve root compression, with symptoms similar to those seen in lumbar stenosis, or irritation of nerve endings at the joints, which results in back pain. These conditions may be treated by decompressive lumbar laminectomy, or laminectomy combined with fusion. In this procedure, instrumentation typically consisting of metal rods and screws is used to stabilize the spine and prevent further slippage. The procedure used depends on the nature and severity of symptoms as well as the cause of the spondylolisthesis. In a similar fashion, spinal instrumentation may be used to treat severe instability, which is defined as excessive motion of one spinal body in relation to another. This usually will cause symptoms by accelerating degenerative changes in the spine, leading to stenosis. Due to the more extensive surgical dissection which must be carried out and the longer operative time required when spinal instrumentation is employed, the recovery period in the hospital may range from several days to a week. However, the patient is still encouraged to get out of bed and begin walking as soon as possible, often on the first postoperative day.
The disorders described here are some of the most common conditions causing low back pain, although there are multiple other processes which can be responsible.
This page is intended to give a simple description of some of the most common conditions which are treated by the neurosurgeon.
Surgeons in the department of neurosurgery at Columbia-Presbyterian medical center have highly specialized training in the management of most spinal disorders, and offer the most up to date state of the art surgery.