L4-5 Disk Extrusion

In patients in whom further treatment is necessary because of pain or neurologic deficit, surgery must be considered and must be preceded by imaging of the lumbosacral spine to rule out a destructive lesion or an anomaly such as spondylolisthesis. The important tests are spinal magnetic resonance imaging (MRI) or, less often, computed tomography (CT) myelography.

If no destructive lesion is present and test results show that the pain and neurologic deficit are caused by the herniated disk, surgery is indicated. The surgeon must keep in mind that the important structure is the nerve root. Adequate exposure is essential to expose the root cephalad and caudad to the extruded fragment and to the lateral margin of the spinal canal. This allows maximal exposure of the disk and nerve root, which can be minimally manipulated. The extruded disk is removed and foraminotomy is done. The root is then retracted medially, the annulus is exposed, and the disk is removed from the interspace to reduce the chance of recurrence. The patient is discharged 1 to 3 days postoperatively and can return to a sedentary job in 2 weeks. Diskectomy, with use of the operating microscope, is also a satisfactory procedure if done at the correct level to adequately expose the root.

The midline disk herniation is a much more serious problem. The entire cauda equina can be compressed at the level of the rupture. Because of the danger of irreversible neurologic damage, bilateral sciatica demands more urgent evaluation than unilateral sciatica. Any suggestion of sphincter disturbance should lead to urgent spinal MRI or CT myelography, and, if necessary, to decompressive laminectomy with disk removal.

Conservative treatment for lumbar spinal stenosis includes weight loss, physical therapy (to improve posture, strengthen abdominal muscles, and increase lumbar flexion) and nonsteroidal anti-inflammatory agents. Surgery may be required to relieve symptoms or prevent further deterioration and usually involves single or multilevel decompressive laminectomy, sometimes with lumbar fusion.

The patient who does not improve after surgery should be reevaluated to rule out a recurrent disk fragment and to establish that surgery was done at the correct level. If no surgical lesion is found, the patient should be encouraged to exercise and to return to work and attempt to live with the symptoms. Analgesic drugs, especially narcotics and tranquilizing medications, should be avoided. Pain clinics have been helpful in rehabilitating some of these patients. Those with persistent lumbar disk signs but no clinical or radiographic findings should not have any type of surgery. Rehabilitation should be attempted.

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