Probing Into The Regularity And Treatment For Recurrent Laryngeal Nerve Injuries

Objective To determine the Comprehensive prognostic value of spontaneous and evoked electromyography (EMG) in laryngeal paralysis. Methods The characteristics of laryngeal EMG of 91 cases with unilateral vocal cord paralysis (VCP) after thyroid surgery were assessed. All cases were divided into four groups according to the interval of laryngeal EMG after onset, which were group one (2 months shorter, n=13), group two (2 to 4 months, n=23), group three (4 to 6 months, n=36), group four (6 months longer, n=19). We examined and analyzed the waveform morphology and the amplitude of laryngeal EMG during voluntary tasks and the highest evoked compound muscular active potential (CMAP) of thyroiarytenoid muscles (TA). Thepotential amplitude was showed by the percentage of that of the healthy lateral. The criterion of evaluation on evoked potential was attained by calculating statistical confidence interval. Results The highest evoked CMAP in group one was significantly lower than that of the others (P<0.05), but no significant difference was observed between every two groups of the others three groups (P>0.05), so group two and group three were analyzed together. There were 2 recovered cases and 11 unrecovered cases in group one. On the basis of this criterion that a positive prognosis for laryngeal recovery was indicated when the evoked CMAP presented and there was no misdirect generated potential, correct prognostic rate was 92% (12/13). There were 11 recovered cases and 48 unrecovered cases in group two and group three. The highest evoked CMAP was much higher in the recovered than in the unrecovered, significant difference was observed between them (P<0.001). On the basis of the criterion that a positive prognosis for laryngeal recovery was indicated when the highest evoked CMAP was higher than 26.4%, correct prognostic rate was 90% (53/59). On the basis of the criterion that a positive prognosis for laryngeal recovery was indicated when there was no misdirect generated potential and the highest evoked CMAP was higher than 26.4%, correct prognostic rate was 93% (55/59). When the interval from onset to laryngeal EMG recording was longer than 6 months, none of these patients had return of vocal cord mobility whatever were the outcomes oflaryngeal EMG Conclusion Correct prognostic rate can be improved if the prognosis of VCP in different courses is judged respectively by analyzing comprehensively spontaneous and evoked EMGPart 2The display of different injuries of recurrent laryngeal nerve in laryngeal electromyographyObjective To study the display of different types injuries of recurrent laryngeal nerve (RLN) in laryngeal electromyography (LEMG). Methods Forty-seven patients (47 sides) with unilateral vocal cord paralysis (UVCP) after thyroid surgery were studied by LEMG before the operations in which the RLNs were explored. The condition of RLN injury and internal laryngeal muscles was observed and recorded during the operation. Results When RLN explored operations were performed in the 94 patients (94 sides) with UVCP after thyroid surgery the severe injuries of RLN were found. The types of injuries were listed as cut, ligation and adhesion. When the RLN of a patients was cut off or ligated, the waveform morphology of LEMG was recorded either single pattern and noevoked compound muscular active potential (CMAP) or mixed pattern and weak evoked CMAP. No electrical silence or interference pattern was shown. When the RLN was adhered to other tissue, the waveform morphology of LEMG presented either mixed pattern or interference pattern and the CMAP could be evoked out but the CMAP amplitude value was very weak. No electrical silence and single pattern was observed. Conclusions When the RLN was cut off, the waveform morphology of LEMG needn't present electrical silence and the weak CMAP might be evoked out in some cases. The clinical injury of RLN often is followed by inferior clilical innervation.Part 3Nerve exploration and decompression for traumatic recurrent laryngeal nerve injuries induced by thyroid gland surgeryObjective To express finding of recurrent laryngeal nerve (RLN) injury exploration and explore therapeutic effect, indication and timing of nerve decompression for traumatic RLN nerve injury induced by thyroid gland surgery. Methods Included in the present series of study were 87 patients with RLNinjury, including 65 for nerve exploration and 22 for nonsurgical treatment. During nerve exploration, the types, severity of RLN injuries and laryngeal muscular mass were observed, nerve decompression was performed in the patients who were operatively found to have compressing sutures or compression due to cicatricial hypertrophy. Results Injuries caused by thyroid gland surgery mostly are of suture ligation and nerve severance; simple scar compression was found only in 6 cases. Atrophy of the laryngeal muscles was not very serious in patients with a course less than 6 months. In 12 patients with a course less than four months, nerve decompression restored normal functional adductory and abductory motion of the vocal cord in 10 patients and motionless in two. Although functional motion of vocal cord was not seen in two patients with a course less than 4 months and two longer than 4 months, the mass and tension of the reinnervated vocal cord may become much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal cords and physiological phonation. Although nonsurgical treatment improved severe hoarseness, it didn't restore normal functional motion of the vocal cord and normal voice. Conclusions Early and mid-stage RLN exploration and decompression may restore normal motion of the glottis, while there is basis for laryngeal delayed reinnervation in patients with a course more than 6 months. Part 4An comparison of different surgical procedures for unilateral laryngeal paralysisObjective To compare therapeutic effect of recurrent laryngeal neurve (RLN) prosthesis and thyroplasty and vocal cord autologous fat injection. To explore indication and opportunity of operation for traumatic RLN injury inducing unilateral vocal cord paralysis (UVCP). Methods Included in the present series of study were 128 patients with RLN injury inducing vocal cord paralysis (VCP) within course 1 week to 24 months, including 89 for nerve anastomosis of RLNs and Ansa cervicalis, 20 for vocal cord lateral autologous cartilage plombage, 19 for vocal cord autologous fat injection. Therapeutic efficacy were appraised by laryngoscope and strobs-laryngoscope and voice evaluation and voice acoustics parameter analysis of pretreatment and post-treatment. Results 89 patients wth nerve anastomosis of RLNs and Ansa cervicalis all hadn't the recovery of vocal cord mobility, the mass and tension of the reinnervated vocal cord may become much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal...