1. Excision of a lumbar intervertebral disc protrusion is required in only a small proportion of patients with this lesion. 2. A careful clinical and radiological examination of cases of lumbago and pain in the lower limb provides good evidence not only of the presence of a lumbar intervertebral disc protrusion but also of its anatomical level, size and relationships. Such examination is essential for the selection of the patients requiring surgical treatment. 3. In most of these selected cases, a carefully performed operation designed to relieve the affected nerve fibres from forces which stretch and compress them will give satisfying relief of symptoms. In the series reported, 92 per cent of patients were either completely free from symptoms or very greatly improved after operation. 4. The spinal and tension signs present before operation largely disappeared after it. Persistence of a pre-operative neurological deficit after operation is, however, relatively frequent, though seldom disabling. 5. The incidence of post-operative recurrence of symptoms of such severity as to indicate re-operation in the series was 2 per cent.
