Induction of tumor necrosis factor-alpha in Schwann cells after gradual elongation of rat sciatic nerve.

BACKGROUND: Although limb lengthening has become a common treatment, the biochemical responses underlying the adaptation of elongated nerves are unclear. The purpose of this study was to clarify whether expression of cytokines and neurotrophins is altered in gradually elongated peripheral nerves. METHODS: Left sciatic nerves of adult rats were elongated by lengthening the femur up to 20 mm at a rate of 1, 2, or 20 mm/day. The ipsilateral and contralateral sciatic nerves of each group were resected 1, 4, 8, and 16 days after 20 mm of lengthening. mRNAs for interleukin-1beta, interleukin-6, tumor necrosis factor-alpha (TNFalpha), nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4/5 were semiquantified by reverse transcription-polymerase chain reaction. Histological changes were assessed by immunoperoxidase and immunofluorescence staining. RESULTS: Expression of TNFalpha mRNA was markedly induced in the ipsilateral sciatic nerves of the gradually elongated, 1 mm/day and 2 mm/day groups, although to a lesser extent than in the acutely elongated, 20 mm/day group. In contrast, mRNAs for other factors remained undetectable. The mRNA level for TNFalpha in each group was highest 1 day after 20 mm of lengthening. The highly up-regulated level in the acute group declined rapidly within 4 days and slowly thereafter; in contrast, the decrease in the gradual groups was always slow. Even 16 days later, the levels in all groups remained significantly elevated. Unexpectedly, TNFalpha mRNA expression was also induced in the contralateral side of all groups. Immunohistochemical staining showed that TNFalpha-immunoreactive cells in gradually elongated nerves were also positive for S-100 protein but negative for proliferating nuclear cell antigen, indicating that TNFalpha was produced by nonproliferating Schwann cells. CONCLUSIONS: Gradual nerve elongation by limb lengthening induces production of TNFalpha in Schwann cells. Presumably, TNFalpha plays a critical role in the adaptation of peripheral nerves to elongation.

Nodular fasciitis of the ulnar nerve at the palm.

A 42-year-old woman complained of progressive induration in the right palm. As the mass was impossible to separate from the ulnar nerve, we excised the mass together with the digital nerve and grafted 4cm of the sural nerve. The final diagnosis was nodular fasciitis.

Intramedullary bone cementing for the treatment of Colles fracture in elderly patients.

Eighteen patients with Colles fractures, mean age 70 years (range 55-91), were treated by intramedullary bone cementing. The best indication for this technique was an unstable extra-articular Colles fracture with osteoporosis. Bone cement was packed into the canal that was made by curettage of intramedullary cancellous bone from the dorsal fracture site. Intramedullary cementing caused little bleeding from the medullary canal and no irritation of the extensor tendons. Because of rigid fixation, patients could use the affected hand for light activities without any external orthosis the day after surgery. Cortical healing was seen in all cases within three months and there was no cement loosening or other complications during the mean 28 month (range 6-43) follow up period. Intramedullary bone cementing is one of the optimal treatments for Colles fractures in elderly patients.

Posterior interosseous nerve injury complicating ulnar osteotomy for a missed Monteggia fracture.

We describe a 6-year-old boy with a posterior interosseous nerve injury after an ulnar osteotomy for a chronic Monteggia lesion. Although the first consultant did an ulnar osteotomy to reduce the radial head, the posterior interosseous nerve palsy did not recover. Next we found that the posterior interosseous nerve had been drawn into the radiocapitellar joint. It is important to confirm interposition of the nerve at the radiocapitellar joint during corrective osteotomy for a chronic Monteggia lesion.