The efficacy of end-to-side nerve anastomosis of autonomic nerve to somatic nerve vs. end-to-end nerve anastomosis on restoration of bladder function

Abstract

Objective To compare the efficacy of end-to-side nerve anastomosis of autonomic nerve to somatic nerve vs. end-to-end nerve anastomosis on restoration of bladder function and its influence on the donor nerve and its functions. Methods Thirty young adult male Sprague-Dawley rats [mean weight (230±28) g] were randomly divided into 3 groups: control group (n=10), end-to-side anastomosis group (n=10), and end-to-end anastomosis group (n=10). In control group only a L3-L6 laminectomy was performed, in end-to-side anastomosis group the distal end of left L6 ventral root (L6VR) was sutured in an end-to-side fashion to left L4 ventral root (L4VR), and in end-to-end anastomosis group, the distal end of L6VR was sutured in an end-to-end fashion to proximal L4VR. Sixteen weeks after operation cystometry was performed, left tibialis anterior muscle electromyogram (EMG) was recorded, left L6VR nerve segments were resected and stained with toluidine blue for nerve fiber count, L4 nerve innervated tibialis anterior muscle wet weight were measured and hematoxylin and eosin (HE) staining was used to observe muscle morphology. Results In control group, end-to-side anastomosis group and end-to-end anastomosis group, the recorded intravesical pressure was (61.7±2.7), (28.3±3.2), (44.5±4.3) cmH2O (1 cmH2O=0.098 kPa) respectively. Only in end-to-end anastomosis group the lower extremity muscle EMG displayed muscle denervation changes. The average number of myelinated axons of the left L6VR in control group, end-to-side anastomosis group and end-to-end anastomosis group was 1 375±183, 669±164 and 892±175 respectively. The muscle wet weights in control group, end-to-side anastomosis group and end-to-end anastomosis group were (0.688±0.061), (0.694±0.059) and (0.394±0.119) g, respectively. There was significant difference in muscle wet weights between end-to-end anastomosis group and the other two groups (P<0.05). Conclusion Both end-to-side and end-to-end anastomosis can realize micturition function. End-to-side anastomosis shows less effect on donor nerve and its functions than end-to-end anastomosis. Key words: Somatic nerve; Splanchnic nerve; End-to-side nerve anastomosis; End-to-end anastomosis; Nerve regeneration