| Part one: Selective reinnervation of posterior cricoarytenoid muscles by upper root of unilateral phrenic nerveObjective: To explore the experimental results of selective reinnervation of posterior cricoarytenoid muscles by upper root of unilateral phrenic nerve.Methods: Eight Beagle dogs were used in this experiment.The left recurrent laryngeal nerves were severed and anastomosed with upper root of phrenic nerve,and the intralaryngeal adductor branch was cut down and sutured to the left PCA muscle.The left side were used as experimental group.The right RLNs were kept intact,and were used as control group.Videolaryngoscopy and electromyography(EMG)were performed at preoperative,immediately after surgery and,6 months after surgery.After all completion of physiologic testing,the dogs were sacrificed and bilateral PCA muscles and intralaryngeal part of recurrent laryngeal nerves were harvested,then histological examination was carried out for comparative analysis.Results:Preoperatively,the movement of bilateral vocal folds were normal in all dogs.The left vocal folds were fixed immediately after surgery.6 months after surgery,the left vocal folds in all 8 dogs recovered inspiratory abductive movement,and the abductive excusion has no significant difference between left and right sides(P>0.05).Spontaneous and evoked electric potential of the PCA muscles could be observeded in 8 dogs during inspiration preoperatively.The left PCA muscles were electrical silent during normal inspiration,and evoked activities were not induced immediately after surgery.Spontaneous electrical activities and evoked electrical activities were recorded 6 months after surgery,and have no significant difference when compared with postoperative data(P>0.05).There was no significant difference in the cross-sectional area of the bilateral posterior cricoarytenoid muscles fibers after the Masson staining.Muscle collagen relative cross-sectional area and collagen relative cross-sectional area and muscle/collagen cross-sectional area ratio difference were not statistically significant(P>0.05).The laryngeal nerve was stained with toluidine blue and the morphology of the axons was observed under light microscope.Nerve pulp numbers of left and right sides of the recurrent laryngeal nerves have no significant difference.(P>0.05).Conclusion:Selective reinnervation of posterior cricoarytenoid muscles by the upper root of unilateral phrenic nerve can restore inspiratory vocal fold abduction to a satisfactory extent and avoid aberrant regeneration.Conclusion: Selective reinnervation of posterior cricoarytenoid muscles by upper root of unilateral phrenic nerve can restore inspiratory vocal fold abduction to a satisfactory extent and avoid aberrant regeneration.Part two:Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerveObjective: To explore the experimental results of Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerve.Methods: Eleven Beagle dogs were used in this experiment.The left recurrent laryngeal nerves(RLNs)were severed and anastomosed with upper root of phrenic nerve And a reanastomosis of the left TA with left thyrohyoid branches of the hypoglossal nerve with the help of an interposition-free nerve graft.the intralaryngeal adductor branch also was cut down and sutured to the left PCA muscle.The left side were used as experimental group.The right RLNs were kept intact,and were used as control group.Videolaryngoscopy were performed at preoperative,immediately after surgery,6weeks,8 weeks,10 weeks,12 weeks,16 weeks,24 weeks fter surgery,and electromyography(EMG)were performed at preoperative,immediately after surgery and 24 weeks after surgery.After completion of all physiologic testing,the dogs were sacrificed,then bilateral PCA muscles and TA muscles and intralaryngeal part of recurrent laryngeal nerves were harvested,then histological examination was carried out for comparative analysis.Results:Preoperatively,the movement of bilateral vocal folds were normal in all dogs.The left vocal folds were fixed immediately after surgery.At 24 weeks after surgery,the left vocal folds in all 11 dogs were recovered inspiratory abductive movement and phonatory adductive movement,and the abductive excusion and adductive excusion have no significant differences between left and right sides(P>0.05).Spontaneous and evoked electric potential of the PCA muscles could be observeded in 11 dogs only during inspiration and the TA muscles also only could be observeded in all dogs only during pronunciation preoperatively.The left PCA muscles and TA muscles were electrical silent during normal inspiration and pronunciation,and evoked activities were not induced immediately after surgery.Spontaneous electrical activities and evoked electrical activities were recorded 24 weeks after surgery,and have no significant difference when compared with postoperative data(P>0.05).There was no significant difference in the cross-sectional area of the bilateral posterior cricoarytenoid muscles and thyroaytenoid muscles fibers after the Masson staining.Muscle collagen relative cross-sectional area and collagen relative cross-sectional area and muscle/collagen cross-sectional area ratio difference were not statistically significant(P>0.05).The laryngeal nerve was stained with toluidine blue and the morphology of the axons was observed under light microscope.Nerve pulp numbers of left and right sides of the recurrent laryngeal nerves have no significant difference.(P>0.05).Conclusion: Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerve can reinnervating the PCA muscle to trigger abduction during the respiratory cycle and preservation of good voice by strengthening the adductor muscles as well as prevention of laryngeal synkinesis.Part three:The synchronize of Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerve.Objective: To explore the experimental results of Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerve.Methods: Eleven Beagle dogs were used in this experiment.The left recurrent laryngeal nerves were severed and anastomosed with upper root of phrenic nerve And a reanastomosis of the left TA with left thyrohyoid branches of the hypoglossal nerve with the help of an interposition-free nerve graft,the intralaryngeal adductor branch also was cut down and sutured to the left PCA muscle.The left side were used as experimental group.The right RLNs were kept intact,and were used as control group.Videolaryngoscopy and electromyography were performed at preoperative,immediately after surgery,6 weeks,8 weeks,10 weeks,12 weeks,16 weeks,24 weeks fter surgery.Once recorded spontaneous electrical activities the dogs were sacrificed immediately after completion of videolaryngoscopy testing,then bilateral PCA muscles and TA muscles and intralaryngeal part of recurrent laryngeal nerves were harvested,then histological examination was carried out for comparative analysis.Results:Preoperatively,the movement of bilateral vocal folds were normal in all dogs.The left vocal folds were fixed immediately after surgery.at different time points after surgery,the left vocal folds in all 11 dogs were not observed abductive movement and adductive movement.Spontaneous and evoked electrical activities of the reinnervated PCA muscles could be recorded in all cases during inspiration and TA muscles could be recorded in all cases during pronunciation preoperatively.The left PCA muscles and TA muscles were electrical silent during normal inspiration and pronunciation,and evoked activities were not induced immediately after surgery.2 at 6 weeks,spontaneous electrical activities of the reinnervated PCA muscles and TA muscles could be recorded,4 at 8 weeks,4 at 10 weeks,and the last one at 12 weeks spontaneous electrical activities of the reinnervated PCA muscles and TA muscles could be recorded in all cases.Spontaneous electrical activities of the left PCA muscles and TA muscles were recorded at different time points.Electrical activities of the left PCA muscles were recorded only on inspiration and of the left TA muscles were only recorded on pronunciation,no abnormal regeneration electrical activities were observed.The dogs were sacrificed immediately after spontaneous electrical activities were recorded for the first time.Both the adductor and abductor muscles were able to observe the fluorescent staining of synaptophysin.The proportion of recovery synaptophysin was different in each animal,but amounts of synaptophysin of left TA and left PCA were no significant difference(P>0.05).Conclusion: Selective reinnervation of laryngeal abductor and adductor muscles by upper root of unilateral phrenic nerve and hypoglossal nerve can reinnervating the PCA muscle to trigger abduction during the respiratory cycle and preservation of good voice by strengthening the adductor muscles as well as prevention of laryngeal synkinesis. |
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