The effect of delayed disc surgery on muscular paresis.

A prospective study was carried out in 280 patients suffering from sciatica caused by myelographically verified disc prolapse. The patients were divided into three groups according to the following criteria: 1. The doubtful group, selected at random. Patients with doubtful indications for surgery. Treated operatively or not--by drawing lots. 2. Non-operated group. Patients with moderate symptoms and/or continued improvement. 3. Operated group. Patients with imperative indications for surgery. The muscle strength of the lower limbs was measured during maximal isometric voluntary contractions in all the patients 2 weeks after admission. Approximately 50 per cent had paresis. Control examinations of these patients 1 year later showed that operative treatment gave no better prognosis than conservative treatment with regard to the motor function, neither in the group chosen at random nor in the selected groups. The causative factors are discussed.