Purpose: An intraneural hematoma can result after trauma or in relation to clotting disturbances. The decision for clinical observation or descompressive surgical thecniques is still controversial The aim of this study is to compare the evolution of nervous function in three situations: intraneural hematoma; intraneural hematoma droned through epineural neurolysis and surgical exploration of the sciatic nerve without hematoma (CONTROL). Methodology: Thirty Wistar rats, divided in three groups were used in this study. In group A (n=10), an intraneural hematoma was produced through injection of 0.2ml of blood in the right sciatic nerve. In group B, after the production of intraneural hematoma as in group A, epineural neurolysis with consequent blood drainage was accomplished. The last group (CONTROL) was used for evaluation of the isolated effects of surgical manipulation under the nervous function. In this group it was made exposition of the nerve without compression. The evaluation of nervous function was made by “walking track” analysis and use of the sciatic functional index (SFI) of Bain-Mackinnon-Hunter. SFI varies from 0 to -100, representing 0+10 the normal nerve function and -100 total absence of function. Results: The group with isolated hematoma (A) presented initial deficit of 28% (SFI = -28,43) of sciatic function, with total recovery of the damaged nerve function in five days. The group with hematoma in which epineurolysis was accomplished (B) presented initial SFI of -14.42, reaching a normal index since the first postoperative day. There was a significant difference (p<0,05) between the functional indexes among the group A and B until the fifth postoperative day. The functional evaluation of the control group (C) showed an initial SFI similar to preoperative “status”. Conclusion: The isolated presence of intraneural hematoma provokes functional deficit, with recovery of the function in 5 days. The drainage of the hematoma by epineurolysis generates faster recovery, with a normal sciatic function index since the first postoperative day.

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