Some writers have used the term facet syndrome to describe a painful state from facetal hypertrophy that gives rise to a lumbar radiculopathy, indistinguishable from that caused by a ruptured disc or spondylotic disease. Reynolds and colleagues have documented such cases. At operation, the spinal root is compressed against the floor of the intervertebral canal by overgrowth of an inferior or superior facet. Foraminotomy and facetectomy, after exploration of the root from the dural sac to the pedicle, have relieved the pain in some operated cases.
With the disappearance of oil based media for myelography, this is now infrequently encountered. It is a thickening and opaqueness of the arachnoid membrane of the lumbar spinal cord or thickening of the arachnoidal sheaths around the individual roots (normal roots have essentially no epineurium). According to one review, lumbar arachnoiditis even in the past was rare, having occurred in only 80 of 7,600 myelograms, and it should only rarely occur with modern group of water-soluble dyes for myelography if they are used a proper concentration. The clinical features are intractable low-back and leg pain and paresthesia, all positionally sensitive, in combination with neurologic abnormalities referable to lumbar spinal roots.
Multiple previous myelograms (largely a problem of the past), disc rupture, operative procedures, infections, and subarachnoid bleeding have been associated with the process. Some cases have followed spinal anesthesia and even epidural anesthesia by a period of months or years but the mechanism is often not clear. The presumption is that the dura had been breached and often there were clinical signs of aseptic meningitis soon after the procedure. In the absence of such an acute reaction, the later diagnosis of arachnoiditis rests on less-certain grounds.
The MRI shows eccentrically thickened meninges in the spinal canal with arachnoid adhesions and collections of CSF that displace nerve roots (Fig. 10-5). Abnormalities may be even more striking on CT myelographic studies in which the contrast is loculated and fails to outline the roots. Treatment is generally unsatisfactory. Lysis of adhesions under an operating microscope and administration of intrathecal steroids have been of little value, although some experienced surgeons claim otherwise. Epidural injection of steroids is occasionally helpful according to some of our orthopedic surgeon colleagues.
This disorder, referred to in the past as rheumatoid spondylitis and as von Bechterew or Marie-Strümpell arthritis, predominantly affects young adult men. Approximately 95 percent of patients carry the histocompatibility antigen HLA-B27 (which is present in only 7 percent of nonaffected persons of European extraction). Pain, usually centered in the low back, is the main early complaint. Often it radiates to the back of the thighs and groin. At first, the symptoms are vague (tired back, “catches” up and down the back, sore back), and the diagnosis may be overlooked for many years. Although the pain is recurrent, limitation of movement is constant and progressive and comes to dominate the clinical picture. Early in the course of disease there is only morning stiffness or an increase in stiffness after periods of inactivity similar to lumbar osteoarthritis but unusual for the affected age group. In advanced stages, a cauda equina compression syndrome may complicate ankylosing spondylitis, the result apparently of an inflammatory reaction and proliferation of connective tissue (Matthews). Limitation of chest expansion, tenderness over the sternum, decreased motion and tendency to progressive flexion of the hips, and the characteristic immobility and flexion deformity of the spine (“poker spine”) may be present early in the course of the disease.