1. The results of repair of the sciatic nerve and of its main divisions have been analysed in a series of 118 cases, the patients having been under observation for three to eighteen years (average 11·7 years).

2. A result was satisfactory if there was some return of sensibility throughout the autonomous zone (the area of skin supplied exclusively by the damaged nerve) and if the more important muscles of the leg were capable of contraction against gravity and resistance.

3. When the whole of the sciatic nerve is damaged it is necessary to present the results separately for the lateral and medial popliteal divisions.

4. Of forty-seven cases of repair of the medial popliteal nerve 79 per cent showed useful motor and 62 per cent useful sensory recovery. In three out of four cases the correspondence between the degree of motor and of sensory recovery was fairly close.

5. Of seventy-two cases of repair of the lateral popliteal nerve 36 per cent showed useful motor and 74 per cent useful sensory recovery. The latter figure must be regarded with some reserve because sensory "recovery" in the lateral popliteal zone may be due to the ingrowth of nerve fibres from contiguous normally innervated skin. Thus it is not possible to correlate motor and sensory recovery.

6. In eighteen cases of repair of the posterior tibial nerve, there was useful sensory recovery in the sole in twelve. But although there was evidence of recovery in the plantar muscles in eleven cases it was functionally valueless.

7. In repair of the medial popliteal nerve the result was better if suture had been carried out early. In repair of the lateral popliteal nerve there was no evidence that delay was harmful; but the proportion of good results was so low (as judged by motor function alone, sensory recovery being often extraneous) that this exception to a general rule cannot be taken very seriously.

8. Gaps of up to twelve centimetres–estimated after resection of the damaged nerve ends–could be closed without difficulty by the usual technique, and the extent of the gap up to that limit had no influence on the prognosis. The closure of larger gaps, when the knee must be flexed beyond a right angle, is not compatible with good recovery because the post-operative stretching of the nerve causes serious intraneural damage.

9. Nerve grafting has given poor results in repair of the sciatic nerve.

1. We have described what happens to patients a number of years after injury of the sciatic nerve or of its divisions; there were 329 who had been under observation for periods ranging from three to eighteen years. The neurological recovery was recorded in every case and, more important, the behaviour of the limb as appreciated by the patient.

2. Although it was generally true that good neurological recovery and good function went together there were remarkable discrepancies. Isolated paralysis of the medial popliteal or of the lateral popliteal nerve was often compatible with good function, though patients with lateral popliteal paralysis usually needed toe-raising apparatus. Even total sciatic paralysis sometimes gave little trouble.

3. Of the various types of injury, clean wounds and traction lesions led to rather better than average return of function.

4. Some degree of pain was present in about half the cases, and over-response–exaggerated and painful response to an ordinary stimulus–was present in one-third of the cases.

5. Repair of the posterior tibial nerve was rarely worth while; no less than eight out of twelve patients with this type of injury exhibited over-response.

6. One-third of the patients showed vasomotor and trophic disorders: coldness of the affected limb, erythema, thinness or pigmentation of the skin, changes in the nails or oedema.

7. Pressure sores were the most serious consequence of sciatic nerve injury and at some time or other were present in 14 per cent of our patients. The cause was deformity rather than insensibility of the sole.

8. Of the various palliative operations Lambrinudi's tarsal arthrodesis gave such disappointing results that we doubt whether the operation is worth doing. Tenodesis, revived as a time-saving expedient during the war, was a failure. For lateral popliteal paralysis anterior transplantation of tibialis posterior is excellent.

9. Amputation was done in only ten cases. When it was performed for fixed deformity with secondary ulceration the result was satisfactory. When it was done because of pain there was no relief. Amputation is, therefore, avoidable provided that vigorous steps are taken to prevent or correct deformity; it should not be done for the relief of pain.