Occult lumbar spinal stenosis.

Twenty-eight patients presenting with low back pain, associated with sciatic or femoral neuropathy, were found to have lateral recess stenosis occurring as a result of hypertrophy of the facet joints, with preservation within normal limits of the sagittal AP diameter of the lumbar canal. Pathology was believed to be traumatic in origin, and the variable nature of the adhesions suggested recurrent inflammation; the hypertrophy of the facet joints may have been the result of traumatic inflammatory hyperaemia. Radiological investigations were unhelpful. The diagnosis of the condition was made at the time of surgical exploration by the findings of alteration of the facet joints, adhesions and fixity of the nerve roots, normal sagittal AP diameter of the canal, and absence of other significant lesions. Gratifying results were obtained with decompression by wide laminectomy with excision of overhanging facet joints and release of adhesions.