Abstract
1. The risk of injury to the sciatic nerve during closed ischio-femoral arthrodesis by nail and graft has been assessed on the basis of clinical evidence and of anatomical studies in the living and in cadavers.
2. The margin of safety for the nerve is nearly always small.
3. The risk of injury to the nerve is prohibitive when there is marked deformity or hypoplasia of the pelvis. The risk is also increased when the buttock is compressed against the table and, because of the technical difficulties that are entailed, when the hip is in marked flexion. The risk is probably greater in children than in adults.
4. In properly selected cases in which none of these adverse factors is present it is submitted that the risk of nerve injury can be eliminated by proper attention to surgical technique and by the observance of certain definite precautions.
5. When there is doubt in the surgeon's mind about his ability to complete the operation without injuring the nerve the closed technique should be abandoned in favour of the open posterior approach.
