[Display of different injuries of recurrent laryngeal nerve in laryngeal electromyography].

OBJECTIVE: To study the display of different types injuries of recurrent laryngeal nerve (RLN) in laryngeal electromyography (LEMG). METHODS: LEMGs of one hundred and forty-seven patients (147 sides) with traumatic unilateral vocal cord paralysis (UVCP) were studied. After LEMGs, the RLNs exploration operations were performed. The condition of RLNs injury and laryngeal muscles was observed and recorded during the operation. RESULTS: The severe injuries of RLNs were found during operation. The types of injuries were listed as ligation (58 cases), adhesion (28 cases) and cut (61 cases). The waveform morphology of LEMG was recorded less in the patients with the RLNs cut than that in the patients with the RLN ligation or adhesion, respectively. 75.4% RLNs cut showed spontaneous waveform while 96.4% RLNs adhesion and 94.8% RLNs ligation. When the RLN was cut off, single pattern was showed oftener. When the RLN was adhered or ligated, mixed pattern was showed oftener. 92.9% RLN adhesion showed misdirect-regeneration-potentials while 70.7% RLN ligation and 24.6% RLN cut. There were significant difference between two types, but the compound muscular active potential (CMAP) amplitude wasn't significantly different. Evoked amplitude could be recorded in 91.4% patients with ligation and its amplitude was (23.6 +/- 8.1)%, in 85.7% patients with adhesion and its amplitude (16.3 +/- 5.2)%, in 29.5% patients with cut and its amplitude (2.6 +/- 4.2)%. CONCLUSIONS: The display of different injuries of RLN in LEMG presents significant difference. If RLN was cut off, the CMAP might be recorded in most cases. The clinical injury of RLN often is followed by sub-clinic reinnervation.

[Preventing recurrent laryngeal nerve lesions by anastomosing it during thyroid surgery].

OBJECTIVE: To study how to prevent recurrent laryngeal nerve (RLN) lesions by anastomosing it during thyroid surgery. METHOD: In the present study 517 patients with thyroid diseases underwent thyroid surgery from January 1993 to May 2005, with RLNs of 163 cases (187 sides, A group) anatomized and RLNs of 354 cases (438 sides. B group) not anatomized. The RLN in B group were protected generally during thyroid surgery. RLNs of A group were anatomized partly or totally. RESULT: (1) In A group RLNs of 123 cases were partly anatomized and 64 totally. None of all RLNs was injuried. (2) B group 3 sides of 3 cases of all RLNs was injuried. The rate of RLN's lesion is 0.7%, which is significantly higher in A group than in B group. CONCLUSION: Anastomosing RLN during thyroid surgery may prevent its lesions. The length of anatomized RLN must vary with the area and position of thyroid pathological changes. The RLN needn't be anatomized in these patients with the benign thyroid pathological changes which is far away trachea-oesophagus channel.

[Reinnervation of the posterior cricoarytenoid muscle by the phrenic nerve for bilateral vocal cord paralysis in humans].

OBJECTIVE: To reestablish the respiratory abduction of the paralyzed vocal cord through reinnervation of the posterior cricoarytenoid(PCA) muscle by the phrenic nerve in humans. METHODS: In six cases with bilateral recurrent laryngeal nerve paralysis, the phrenic nerve was anastomosed to the anterior branch of recurrent laryngeal nerve, while the adductor branch of recurrent laryngeal nerve was severed and its proximal end was implanted into the PCA muscle belly in one side, for the other side nerve-muscle pedicle technique was used. All cases had been subjected to preoperative and postoperative video laryngoscopy, stroboscopy, electromyography, voice recording and acoustic analysis. RESULTS: Among the 6 patients, it is observed in five cases' phrenic nerve reinnervation side the inspiratory abducent motion evidently recovered, and the abducent range was from 3 to 5 mm, While only slight abductent motion or no motion could be recorded on the other side reinnervated with nerve-muscle pedicle technique, and the vocal cord excursion on this side was less than 1 mm in all cases. It is because the glottis is broad enough for the patients to have daily activities without short of breath, so all of them were decannulated postoperatively. The reinnervated PCA muscle by the phrenic nerve showed typical inspiratory high frequency discharge with 100-200 ms delay as compared with the other side, indicating the phrenic motoneuron pattern. No long-term diaphragmatic paralysis and lesion of respiratory function was found. All cases' voice was not weakened, and no aspiration occurred. CONCLUSION: The phrenic reinnervation is feasible clinically for treating vocal cord paralysis, and it is found to be more effective for restoring inspiratory abducent function than the nerve-muscle pedicle technique.