Effects of tension at the site of coaptation on recovery of sciatic nerve function after neurorrhaphy: Evaluation by walking-track measurement, electrophysiology, histomorphometry, and electron probe X-ray microanalysis

Abstract

The effects of tension at the site of coaptation on recovery of sciatic nerve function after neurorrhaphy were studied by evaluating walking-track measurements, nerve conduction velocity measurements, histomorphometry, and electron probe X-ray microanalysis. Forty adult male Lewis rats underwent right sciatic nerve (SN) transection followed by one of four different nerve repair procedures (N = 10 rats per group). In Group 1, the gap was repaired by end-to-end epineural coaptation. In Group 2, a 5-mm segment of SN was resected, and the defect was repaired under high tension by epineural neurorrhaphy. In Group 3, a 5-mm segment of SN was resected, and the defect was repaired with a 5-mm interposition nerve graft. In Group 4, a 5-mm segment of SN was resected. Then, to lessen the tension that follows neurorrhaphy, an anchoring suture was added. Finally, end-to-end coaptation was performed. Walking-track analysis showed better functional recovery in Group 1 than in Group 2, and better recovery in Group 3 than in Group 2. Group 4 showed a tendency toward better recovery comparing with Group 2. Electron probe X-ray microanalysis revealed higher Na, Cl, and K peaks in axoplasm accompanied by increase in the endoneural fluid pressure (EFP) in Group 2 than those of Group 1. This higher level of Na, Cl and K may be due to impairment of axonal sodium and potassium transport mechanism in Group 2. Increase in EFP may affect nerve regeneration.

Factors that influence peripheral nerve regeneration: An electrophysiological study of the monkey median nerve

“…Though other studies in the primate have found that regeneration under mild tension did not affect the final outcome,45 we found that recovery of the CMAP was slowed when repair was carried out under slight tension (see Fig 3) and the time of reinnervation of the CSAP was delayed (see Fig 6). The adverse effect of tension on regeneration20 may be the result of interference with the blood supply to the nerve,48 and our findings support that even small nerve gaps should be bridged to avoid even modest tension.…”

Differential Effects of Coating Materials on Viability and Migration of Schwann Cells

“…Tensionless coaptation of nerve stumps is known to be inevitable for successful nerve healing [3,4]. However, the recoil of nerve stumps due to debridement or delayed surgical care causes nerve gaps which frequently impede this tensionless nerve repair and remain a great challenge in clinical practice [5].…”

Effects of eliminating tension by means of epineural stitches: a comparative electrophysiological and histomorphometrical study using different suture techniques in an animal model

“…An alternative way to correct such an imperfection is to anchor epineural stitches at a distance, so as to draw the two stumps closer together and avoid concentrated tension at the nerve suture site itself, displacing all tension to parts further away from the nerve. This suture technique is no novelty, having already been described in several papers 13,14 . The results of the experiment described in this paper showed that regarding motor latency, there was no statistical difference when employing this technique (epineural suture under tension) when compared with the use of grafts.…”