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The 2004 Annual Meeting (January 14-20, 2004) of OASYS_NEW |
Not yet assigned to a slot - 4:00 AM
Peripheral Nerve Compression Due to Intraneural Hematoma: Experimental Study in Rats
Scopel GP1, Scopel S1, Faria JCM1, Busnardo F2, and Ferreira M3. (1) Division of Plastic Surgery, Univesity of Sao Paulo, Rua do Paraíso 719 apt 71, São Paulo, Brazil, (2) Division of Plastic Surgery, University of Sao Paulo, R Joao Moura,870 ap 122A, Sao Paulo, Brazil, (3) Plastic Surgery Division, University of Sao Paulo, Rua Mario de Azevedo 338, Sao Paulo, Brazil
Introduction: Intraneural hematoma may result from trauma or clotting disturbances. Treatment option range from clinical observation to surgical release. The authors used an experimental model in rats in order to evaluate the effects of intraneural hematoma and the results of surgical decompressions. Materials and methods: Forty (40) male Wistar rats were divided into 4 groups. The sciatic nerve was wrapped around in all groups with a silicone tube. In GROUP A (control) the sciatic nerve was wrapped by silicone tube. The same procedure was performed on GROUP B, with subepineural injection of 0.2 ml of autologous blood. In GROUP C, after formation of a hematoma, the silicone tube was removed and epineurotomy performed. In GROUP D, only the silicone tube was removed after formation of a hematoma. Nerve recovery was evaluated periodically for 61 days using the walking track method and the Sciatic Function Index (SFI) of Bain-Mackinnon-Hunter. The SFI varies from 0 to -100, zero being the normal function of nerve and -100 being the total loss of function. At the end of the study, a histological assessment of the nerve was performed at 3 levels: proximal, middle and distal to compressed site. Results: GROUP A (control) presented function deficit of 21% (SFI=-21) and returned to initial values on the 7th post-operative day. GROUP B (hematoma and extrinsic compression) exhibited the worst function (SFI= - 83) after surgery and recovered in 31 days. GROUP C (removal of silicone tube and epineurotomy) had 44% loss of function (SFI = -44) and returned to normal on 15th post-operative day. GROUP D (only removal of the silicone tube) presented SFI -26 and recovered on the 7th post-operative day. Statistical analysis of the SFI showed significant differences between expectant option versus surgery (p<0.0001), with better functional recovery observed in GROUP D. Conclusion: In this study, intraneural hematoma with extrinsic compression causes a significant loss of function with recovery of the sciatic function in 31 days. Surgical release results in shorter functional recovery period (7 days). Compared to clinical observation, decompression with epineurotomy showed significant improvement of the sciatic function.