Background: We conducted a prospective study to investigate voice quality after transoral endolaryngeal laser surgery in terms of ability to communicate effectively. Eighty patients with T1 or T2 glottic carcinoma were enrolled in the study. The main objective was to identify the influence of type and extent of surgery on postoperative voice parameters after endoscopic laser surgery.
Material and methods: The postoperative mechanism of phonation was assessed by videostroboscopy six months after surgery at the earliest. A phonetogram was produced and its area calculated (relative phonetogram, RP) in relation to a gender-specific normal phonetogram. A speech therapist (ST) and a trained otolaryngologist (TO) rated each voice independently for communication ability in a grade from 1 (poor) to 6 (near normal).
Results: After simple cordectomy the mean values were as follows: RP = 24.8%, TO = 3.26, ST = 3.33. When the anterior commissure was completely preserved mean results were better (RP = 34%, TO = 3.92, ST = 3.83). Results were worse following extended cordectomy (RP = 14.7%, TO = 2.82, ST = 3.00) and transglottic resection (RP = 13.7%, TO = 2.30, ST = 2.86), but similar within these two groups. The parameters RP, TO, and ST do not differ significantly between the group who had speech therapy after surgery (N = 33) and the group who did not (N = 47). Voice production at glottic level yields better results for every parameter than supraglottic substitute phonation. The amount of tissue removed was less significant.
Conclusion: We conclude that postoperative phonatory results correlate with the postoperative mechanism of phonation. There is no linear correlation with the amount of tissue removed. Comparing similar types of resection preservation of the anterior commissure plays a key role. From the data in this study there is no evidence of a significant benefit from speech therapy. The parameter RP is an effective and relatively simple parameter to complete auditive voice assessment.