Disorders of the lumbar intervertebral discs are a major source of disability and economic loss. They usually occur in the 35-45 age groups, men being affected marginally more than women. They are less often seen in adolescence, when there is an in creased incidence in boys, and the condition tends to run a more protracted course. Analysis of numerous reports indicates that injury is a prime factor in the onset of lumbar disc prolapse in only 12-14?o of patients. Injury is usually only a precipitating factor, as a biochemical defect is the underlying basic cause on which mechanical stresses are superimposed. Thus many closed methods of treatment are likely to be beneficial in view of the self-limiting nature and expected propensity of the lesion to resolve spontaneously if additional stress or strains on the lumbar spine are removed or minimised. These may take the form of bed rest, an efficient method if applied seriously, or immobilisation of the lumbar spine in a plaster jacket or Gold thwait type of belt. Alternatively, the stress on the lumbar spine may be relieved by traction, especially if combined with continuous bed rest. Epidural hydrocortisone also helps. Goldthwait in 191 11 first described the syndrome of lumbar disc herniation, diagnosing the presence of a disc protrusion to account for the development of paraplegia in a patient under going manipulative treatment for sciatica. No operation was performed, and the diagnosis was confirmed at necropsy. Belated recognition of this important lesion followed the description by Mixter and Barr2 of the results of surgery for lumbar disc prolapse. As the diagnosis was made with increasing frequency, surgical invervention became extensively and often unnecessarily employed, but with further experience of the spontaneous resolution that occurs in the syndrome in most cases and the relief produced by conservative measures in many patients, there is now a more balanced view of the need for surgical treatment. There is a wide variation of symptoms and signs from minor degrees of backache to the fully developed picture of lumbo sacral nerve root radiation, with neurological and orthopaedic signs (see figure). In many cases, the disc disorder is contained within the annulus-that is, there is a disturbance in the nucleus, biochemical in nature, which results in an increased intradisc pressure or minor incomplete annular ruptures, and these produce defective function of the disc and its segmental spinal joint. This is associated with backache, which may radiate to the buttock and as far distally as the greater trochanter of the femur. This limited radiation of pain posterolaterally should a b c d