SCIATIC-NERVE - PARADOXIC HYPERTROPHY AFTER AMPUTATION IN YOUNG-PATIENTS

PURPOSE: To evaluate the appearance of the sciatic nerve after leg amp utation.MATERIALS AND METHODS: Magnetic resonance (MR) images were obt ained in seven patients (age at amputation, 11-19 years) who underwent above-knee amputation to treat osteogenic sarcoma. Images were evalua ted for sciatic nerve enlargement. Findings were correlated with the t ime after amputation. RESULTS: All seven patients were found to have a markedly enlarged sciatic nerve in the stump of the amputated leg. Th e enlargement extended proximally from the point of nerve transection to a level posterior to the femoral neck (8-27 cm) depending on the le ngth of the stump. No evidence of sciatic nerve enlargement was found in the opposite leg or on preoperative MR images that were available i n three of the patients. Moreover, in one patient with a sarcoma who u nderwent a leg-sparing procedure, no sciatic nerve enlargement was see n postoperatively. The thickness of the distal sciatic nerve was relat ed to the time after amputation. CONCLUSION: Hypertrophy of the sciati c nerve occurred after above-knee amputation in young patients. This f inding differed from atrophy of the nerve that has been reported previ ously in older patients.