[Comparative study on simultaneous bilateral and unilateral posterior vocal cord resection using CO2 laser for bilateral vocal cord paralysis].

Abstract

Objective: To compare and analyze the efficacy of bilateral and unilateral posterior vocal cord resection with CO₂ laser under endoscopy in the treatment of bilateral vocal cord paralysis. Methods: This case series study retrospectively analyzed the data of 110 patients with bilateral vocal cord paralysis who underwent endoscopic CO₂ laser posterior cordotomy at the Department of Otolaryngology-Head and Neck Surgery, the First Affiliated Hospital of Naval Medical University, from October 2016 to January 2023. The cohort consisted of 36 males [mean age (45.5±9.1) years, range 24-72 years] and 74 females [mean age (47.2±10.1) years, range 22-67 years]. Among them, 47 patients underwent simultaneous bilateral posterior cordotomy (bilateral cordotomy group), while 63 patients underwent unilateral posterior cordotomy (unilateral cordotomy group). Pre-and postoperative indicators, including swallowing function, glottal size, and vocal function (subjective and objective assessments), were compared between the two surgical approaches. The Wilcoxon signed-rank test was used to analyze changes in swallowing function, glottal size, and vocal function (subjective and objective assessments) within each group before and after surgery, whereas the Mann-Whitney U test was utilized to assess differences between groups. Results: Postoperative follow-up was 1-5 years [median follow-up time was 1.6 (1.3, 2.0) years].The one-time extubation rate was 71.4%(45/63)in the unilateral posterior vocal cord resection group and 87.2%(41/47)in the bilateral posterior vocal cord resection group, significantly higher in the bilateral group (χ2=3.94,P<0.05). One week after surgery, the swallowing function score of unilateral cordotomy group was 2 (1, 2.5) points, which was significantly better than that of bilateral cordotomy group [2 (1.5, 3) points, Z=-2.118,P<0.05], and the swallowing function score of both groups returned to normal 3 months after surgery. There were no significant differences in preoperative glottic closure during inhalation, auditory perceptual evaluation (GRBAS), objective voice analysis, and Voice Handicap Index-10 (VHI-10) between the two groups (P>0.05). Postoperatively, the maximum transverse diameter of the posterior glottis during inspiration in the unilateral cordotomy group was 4.49 (4.24, 4.77) mm, significantly smaller than that in the bilateral cordotomy group, which was 5.05 (4.52, 5.62) mm (Z=-4.103, P<0.05). Among the GRBAS parameters, G (grade of hoarseness), B (breathiness), and A (asthenia), as well as VHI-10 scores and objective voice analysis parameters [jitter, shimmer, harmonic-noise ratio (HNR), and maximum phonation time (MPT)], were significantly better in the unilateral cordotomy group compared to the bilateral cordotomy group, with statistically significant differences (P<0.05). Conclusions: Unilateral posterior vocal cord resection using CO₂ laser is simple and feasible for the treatment of bilateral vocal cord paralysis, with shorter recovery time, maximal preservation of laryngeal phonatory function, and fewer complications compared to bilateral resection. However, the one-time extubation rate is higher with bilateral resection, reducing the need for a second surgery and associated patient discomfort. This study offers guidance for clinical decision-making in the surgical management of bilateral vocal cord paralysis.