[Clinical characteristics and efficacy of vocal fold epidermoid cysts coexisting with sulcus vocalis]

Objective: To investigate the clinical characteristics and voice outcomes after laryngeal microsurgery for vocal fold epidermoid cysts coexisting with sulcus vocalis. Methods: The clinical data of 115 vocal fold epidermoid cysts coexisting with sulcus vocalis patients in Shandong provincial ENT hospital, were retrospectively analyzed, including 49 males and 66 females, aged 17-70 years old, and the duration of hoarseness ranged from 6 months to 30 years. All patients underwent surgery through suspension laryngoscope and microscope under general anestgesia. Ninety-four patients were treated with microflap excision of sulcus vocalis, cyst wall, and contents.And 21 patients that occulted with mucosal bridges were applied mucosal bridges resection (2 cases) and mucosal bridges reconstruction (19 cases) respectively. Videolaryngoscopy, subjective voice evaluation (GRBAS), objective voice evaluation, and Voice Handicap Index(VHI) were performed before and after surgery. All patients underwent histopathologic examination and follow-up after the procedure. The preoperative acoustic parameters of patients with vocal fold epidermoid cysts coexisting with sulcus vocalis were compared with those of vocal fold mucus retention cysts and simple vocal fold epidermoid cysts by independent samples t-test. The patients were compared by paired t-test for preoperative and postoperative parameters. Results: Significant reduction or lack of mucosal waves were shown via videolaryngostroboscopy in all 115 cases.In addition, vascular changes including dilation, tortuousness, increased branches, and abrupt direction change were shown on the cystic area. Eighty-one patients were detected cysts and/or sulcus vocalis by preoperative laryngoscopy, and intraoperative microscopic findings in the remaining 34 patients. The intraoperative microscopic examination revealed a focal pouch-like deficit plunging into the vocal ligament or muscle. The deep surface of the mucosal bridges was sulcus vocalis, and that in 89 cysts was lined with caseous content. Histopathology demonstrated a cystic cavity structure lined with squamous epithelium and caseous keratin desquamation inside the cystic cavity. Four of 115 patients were lost at follow-up and excluded from the analysis of voice outcomes after surgery. There was no significant mucosal wave and the voice quality in all but 14 patients 1month after surgery. Except for the fundamental frequency and noise harmonic ratio, all other voice parameters[ G, R, B, A, VHI-10, jitter, shimmer, maximum phonatory time (MPT) ]showed a significant improvement 3 months after surgery(t=15.82, 20.82, 17.61, 7.30, 38.88, 7.84, 5.88, -6.26, respectively, P<0.05). Then mucosal waves and the voice quality were gradually improved and became steady in 6 months after surgery. The subjective and objective voice parameters[G, R, B, A, VHI-10, jitter, shimmer, noise to harmonic ratio(NHR), MPT], except for the fundamental frequency, were all significantly improved(t=23.47, 25.79, 18.37, 9.84, 54.45, 10.68, 8.07, 3.24, -9.08, respectively, P<0.05). In addition, there were 2 patients with no significant improvement after the operation. Steady function with no complications was observed during the 12 months (up to 3 years in 34 patients) follow-up period in 111 patients. Conclusion: Ruptured vocal fold epidermoid cysts can result in sulcus vocalis and mucosal bridges. Characteristics changes in preoperative videolaryngoscopy are effective diagnostic tools. The complete excision of the cyst wall and repair of the lamina propria can lead to satisfactory long-term effects.