| Bilateral paralysis of the recurrent laryngeal nerve (RLN), most often caused by cervical operation, trauma and tumor, brings the vocal cords to a fixed paramedian position that results in a severe impairment of respiration. Relief of the inspiratory dyspnea is currently obtained either by tracheostomy or by surgical procedures such as arytenoidectorry or arytenoidopexy. Those patients, however, pay for the respiratory improvement both with the discomfort of a permanent tracheostomy and with the losing of the phonatory function. So, a more convenient approach to rehabilitation of bilateral paralysis of the larynx seems to be that aimed at reestablishing the inspiratory opening of the glottis through reinnervation of the posterior cricoarytenoid muscles (PC AM).Many researchers agree that it should selectively restore the function of laryngeal muscles. The operation method, suturing the phrenic nerve(PN) to the distal stump of the RLN after intralaryngealsectioning of its adductor branch, was widely adopted in this area. But it can't be used to bilateral paralysis of RLN. The ideal method is to obtain reinnervation of the PCA muscles and intact phrenic nerve. It can be obtained by end-to-side neurorrhaphy technique.There was no same report about reconstructing the function of PCAM by end -to- side neurorrhaphy. The aim of this research is to study the feasibility and effect of RLN-PN end-to-side neurorrhaphy, compared with RLN-PN end-to-end neurorrhaphy and RLN anastomosis, in order to find a rational operation for bilateral paralysis of the RLN.Methods: Sixty rats were divided into four groups at random: RLN-PN end-to-side neurorrhaphy (Group A ), RLN-PN end-to-end neurorrhaphy (Group B ), RLN anastomosis (Group C),Control group(Group D),every group has 15 rats. Under the operative microscope, the right RLNs were separated and cut to prepare the model of unilateral paralysis of RLN. To every anastomotic group, the RLNs were dissected distally to its terminal branches, where the adductor-abductor sorting out occurs. Then the adductor branches were cut. To Group A, after exposing the right PN at cervical part, a window was opened at the PN epineurium, then suture the distal RLN (45?angle bevel) to the window .To Group B, the right PNs were cut at the entrance of thorax, the distal end of PNs were reversed and sutured to the distal end of RLNs end-to-end. To Group C, the RLNs were sutured directly. To control group, the RLNs were severed and ligated.After operation, all the rats were examined by fiberolaryngoscope to confirm that the right RLNs were fixed at paramedian position. After 2 months, the recovery of abduction was investigated and recorded by fiberolaryngoscope. Then, the electromyogram of bilateral PCAMs were examined by electromyograph, obtained the recovery ratio of induced active potential latency and peak value. After these examinations, the PCAMS were resected, fixed and stained to evaluate the musle atrophy, obtained recoveryResults: (l)Two months after operation, fiberolaryngoscope was used to examine the recovery of right vocal cords' movement, showing that Group C was the best, Group D was the worst .There were significant differences between Group A, Group B and Group C (P<0.05 ). There were no significant difference between Group A and Group B (P>0.05). (2)Three anastomostic group can record spontaneous and induced myoelectric activity. Group D could only record fibrillation potential. The recovery ratio of latency and peak value showed that Group C was the best. There were significant difference beween Group A, Group B and Group C (p<0.05) There were no significant difference between Group A and Group B(P>0.05). (3)Histological examination showed that there were apparent myoatrophy among Control group. The tap between muscle fibers became wide and connective tissues proliferated. Under the microscope, computing the fiber mumbers in each high power field showed that Group C had recovered to normality. There weresignificant differences between Group A, Group B and...
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