Effect of resection depth of early glottic cancer on vocal outcome: An optimized finite element simulation

Abstract

Objectives/Hypothesis To test the hypothesis that subligamental cordectomy produces superior acoustic outcome than subepithelial cordectomy for early (T1-2) glottic cancer that requires complete removal of the superficial lamina propria but does not involve the vocal ligament. Study Design Computer simulation Methods A computational tool for vocal fold surgical planning and simulation (the National Center for Voice and Speech Phonosurgery Optimizer-Simulator) was used to evaluate the acoustic output of alternative vocal fold morphologies. Four morphologies were simulated: normal, subepithelial cordectomy, subligamental cordectomy, and transligamental cordectomy (partial ligament resection). The primary outcome measure was the range of fundamental frequency (F0) and sound pressure level (SPL). A more restricted F0-SPL range was considered less favorable because of reduced acoustic possibilities given the same range of driving subglottic pressure and identical vocal fold posturing. Results Subligamental cordectomy generated solutions covering an F0-SPL range 82% of normal for a rectangular vocal fold. In contrast, transligamental and subepithelial cordectomies produced significantly smaller F0-SPL ranges, 57% and 19% of normal, respectively. Conclusion This study illustrates the use of the Phonosurgery Optimizer-Simulator to test a specific hypothesis regarding the merits of two surgical alternatives. These simulation results provide theoretical support for vocal ligament excision with maximum muscle preservation when superficial lamina propria resection is necessary but the vocal ligament can be spared on oncological grounds. The resection of more tissue may paradoxically allow the eventual recovery of a better speaking voice, assuming glottal width is restored. Application of this conclusion to surgical practice will require confirmatory clinical data.

Voice outcome after unilateral ELS type III or bilateral type II resections for T1‐T2 glottic carcinoma: Results after 1 year

“…It has been shown that the postoperative voice outcome in limited resections such as subepithelial and subligamental resections (type I‐II according to the European Laryngological Society [ELS] classification) is normal or near to normal and that voice outcome for TLM and RT in these lesions is comparable . However, the postoperative voice is generally poorer in more extended resections (type III‐IV) than in superficial resections (type I‐II) . This is consistent with greater glottal insufficiency due to tissue loss .…”

“…However, the postoperative voice is generally poorer in more extended resections (type III‐IV) than in superficial resections (type I‐II) . This is consistent with greater glottal insufficiency due to tissue loss . Moreover, when the tumor extends to the anterior commissure (AC), poorer voice outcome is seen, regardless of the treatment modality .…”

Human Speech: A Restricted Use of the Mammalian Larynx

“…For humans who do not vocalize out of the context of speech, however, the vocal ligament may become superfluous. Surgeons have found that removal of the ligament (known as a cordectomy) may not have a profound effect on conversational speech (Hillel et al, 2013; Mau et al, 2015). Caution should be used, however, in applying this perspective to current surgical management of the vocal ligament.…”

Transoral Laser Microsurgery in Early Glottic Lesions

“…A computer model published by Mau in 2015 provides theoretical support for this finding although the authors state that further clinical data are required to support this conclusion [105•].…”