LOCALISED ARACHNOIDITIS COMPLICATING LUMBAR DISC LESIONS

LOCALISED ARACHNOIDITIS COMPLICATING LUMBAR DISC LESIONS A. 0. RANSFORD and B. J. HARRIES, LONDON, ENGLAND From the Department of Neurosurgery, University College Hospital, London The possibility that arachnoiditis of the cauda equina may complicate prolapse of a lumbar disc was not raised until French published eight cases in 1946. We present five cases treated in the above unit during the last eight years. All our patients had intermittent symptoms of several years’ duration and physical signs consistent with a lumbar disc protrusion. There were no special clinical features to suggest the complication of arachnoiditis. Plain radiographs of the lumbar spine were generally unhelpful, but the possibility of the dual diagnosis was indicated by preliminary myelography. Insertion of Myodil in the L.4-5 or the L.5-S.1 space was difficult in three of the cases, a slow flow of cerebrospinal fluid being obtained with a poor rise and fall of pressure on jugular compression. It was necessary to insert the Myodil by cisternal puncture in two cases. Screening indicated that local arachnoiditis was the cause of the difficulties. A complete or partial block to the flow of the Myodil was present at the appropriate level and the adjacent nerve roots appeared thickened. The cerebrospinal fluid obtained before the insertion of Myodil was examined in all cases; the protein was raised when a block was present but there were no special features. The Wassermann reaction or its equivalent was negative in each case. At operation, laminectomy was performed at the appropriate level. The presence of a disc protrusion, of annulus “bulging” or of fibrotic scarring of the disc from an earlier protrusion was confirmed visually in all cases. In two cases the theca was opaque locally and in another it was locally constricted. On opening the theca the involved arachnoid was found to be thickened and opaque, forming a circumscribed cuff generally two to three centimetres in extent. The roots of the cauda equina were pink, swollen and matted together, with fine adhesions everywhere. Globules of contrast medium were trapped in the interstices of this fine meshwork. In all five cases no predisposing cause of the arachnoiditis other than the disc lesions could be implicated. In particular, the use of contrast medium could not be invoked. CASE REPORTS Two cases are given in detail. For brevity the other three cases are presented in tabular form. Case 1-A foreman aged fifty-eight attended in 1963 for intermittent low back pain and right-sided sciatica of thirteen years’ duration. For the last eight years he had noticed weakness of the right leg, worse on walking. On examination he held the lumbar spine stiffly; there was a tilt to the left and tenderness over the fifth lumbar spine. Straight-leg raising was full ; there was one centimetre of wasting of the right thigh and calf, with generalised weakness of the right leg. There was diminished sensibility over the right L.5 dermatome. The tendon reflexes in the legs were absent. Radiographs of the lumbar spine showed diminution of the L.4-5 disc space. Lumbar puncture was difficult, but entry was eventually successful in the L.5-S.l space (protein 535 milligrams per 100 millilitres, white cells 1 per cubic millimetre, Wassermann reaction negative). Manometry suggested a block. Accordingly, Myodil was introduced by cisternal puncture (protein 36 milligrams per 100 millilitres). The myelogram showed a partial block at L.4-5 with a lesser block at L.3-4, suggestive of extradural compression by annular bulging of the intervertebral discs. The streaky appearance of the cauda equina was characteristic (Fig. I). 656 THE JOURNAL OF BONE AND JOINT SURGERY

LOCALISED ARACHNOIDITIS COMPLICATING LUMBAR DISC LESIONS

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