[The effect of neurolysis on the recovery of experimentally induced entrapment neuropathy].

While chronic entrapment neuropathy is a common problem in orthopaedic practice, controversy remains over which is the most appropriate surgical procedures. There have been few experimental studies addressing this problem. This study was undertaken to compare the effects, as well as the risks, of various surgical procedures on experimentally induced chronic entrapment neuropathy in rat. Ninety adult male Wistar rats (250-300 g) were used as the experimental animals. The sciatic nerves were wrapped by silastic tubes each 10 mm long with an internal diameter of 1.5 mm. At eight months later, after the nerves had demonstrated changes compatible with clinical chronic entrapment neuropathy, the tubes were removed and simple decompression, external or internal neurolysis was carried out on the entrapped nerve. Nerves at 1, 2, 4 and 6 months after surgery were morphologically and functionally examined. Electrophysiological and histological changes were gradually ameliorated after simple decompression. The externally neurolysed nerve showed improvements in the normal nerve functions. Internal neurolysis on chronically entrapped nerves produced a deterioration in the nerve functions, as well as in the nerve structures. We concluded that more favorable results were achieved by the external neurolysis, whereas internal neurolysis was a very harmful procedure for chronic entrapment neuropathy.