Effects of Two Different Meshes Used in Hernia Repair on Nerve Transport

BACKGROUND: We aimed to investigate the effects of two different types of mesh used in hernia repair on nerve transport and neural injury. STUDY DESIGN: Forty-five Wistar-albino rats were randomly allocated to three groups. Basal neural transport on the index of the left sciatic nerve was performed in all groups before surgery. In the control group, only sciatic nerve manipulation was performed. Other groups received a cuff around the index sciatic nerve. The second group received a monofilament polypropylene and the third group received a polytetrafluoroethylene mesh. Effects of entrapment on neural transport were evaluated by electromyography on the 28th day. Tissue samples from sciatic nerves were taken for evaluation of nerve injury. RESULTS: There was no significant difference between basal latency and amplitudes (p = 0.609 and p = 0.152, respectively). But latency was significantly different 4 weeks after the operation (p < 0.0001). At post hoc evaluation, entrapment groups had longer latency times compared with those in the control group (p = 0.006 and p < 0.0001, respectively). But the increase in latency between entrapment arms was similar on the 28th day (p = 0.601). Both initial and late term amplitudes were similar (p = 0.364 and 0.913, respectively). Histologic evaluation by Masson's trichrome staining revealed high fibrosis scores and increased collagen deposits, especially in the polypropylene group (p < 0.0001), and increased inflammation in the polytetrafluoroethylene group (p < 0.001). CONCLUSIONS: Our results showed that the two most commonly used meshes in tension-free hernia surgery have different effects on nerve physiology and morphology. We concluded that alterations in nerve physiomorphology are from the properties of the mesh and may be the source of postoperative pain in hernia surgery. (J Am Coll Surg 2008;207:670-675. (C) 2008 by the American College of Surgeons)