OBJECTIVETo evaluate postoperative glottic area and vocal quality of three various surgical techniques for treating bilateral vocal cord paralysis, including laser arytenoidectomy (Group A, 24 cases), reinnervation of the posterior cricoarytenoid muscle by phrenic nerve (Group B, 9 cases) and arytenoidectomy accompanying lateral cordopexy by extralaryngeal approach (Woodman's procedure, Group C, 13 cases).

METHODS46 cases suffered from bilateral recurrent laryngeal nerve injury were included in our study. The pre-postoperative glottic measurement and vocal acoustic parameters were analyzed.

RESULTSThe decannulated cases in group A and group B and group C were 22, 8, 13 respectively. The post-operative mean maximal glottic area was (47.2 +/- 7.4) mm2, (78.3 +/- 16.0) mm2, (48.1 +/- 6.5) mm2 respectively. Group B cases glottic area was larger than that of group A and group C (t value were 4.46 and 3.85, P value were 0.000 and 0.001). No significant difference was found between group A and group C (t = 1.68, P = 0.101). After surgery, in group A, 17 cases voice quality was the same compared with that of before surgery, and 7 cases voice quality had become worse; In group B, the voice quality had become better in 5 cases, completely recovered in 1 case, and had not change in 3 cases; In group C, the voice quality had become deteriorated in 10 cases and no change in 3 cases. And in group B, ipsilateral diaphragm paralysis in 9 cases after surgery, whose vital capacity and forced vital capacity had decreased to 72%-84%, 76%-84% of that before the surgery respectively; and the diaphragm mobility had recovered by 35%-76% respectively, while vital capacity and forced vital capacity had become 93%-97%, 91%-98% of that before the surgery. In Group B, all cases' pulmonary function was normal half a year postoperatively.

CONCLUSIONSReinnervation of the posterior cricoarytenoid muscle by phrenic nerve seems to be best procedure with better post-operative voice and larger glottic area. Although the sufficient airway for decannulation can be acquired in Group A and Group C, but most of patients in Group A had pre-operative vocal level and badly abnormal in Group C.