Effects of diode laser setting for laryngeal surgery in a rabbit model
To study the damaging effect of different diode laser settings on vocal folds 7 days after injury in a rabbit model.
Twenty-one male New Zealand white rabbits were randomized into three groups with seven animals per group. A 980-nm diode laser was used to create a single spot injury in each vocal fold. Different modulation frequencies (10 Hz versus 1000 Hz) in pulsed mode, different powers (3 W versus 5 W), and distinct wave modes of radiation (pulsed versus continuous) were compared.
The extent of the inflammatory infiltrate and ablation crater were greater when using 5-W optical power compared with 3 W. The extent and depth of the inflammatory infiltrate, and the width and depth of the ablation crater were greater with continuous wave mode compared with pulsed mode. The density of collagen fibers only increased when using the laser in continuous wave mode.
The use of the 980-nm diode laser with an output power of 5 W produced an increased extent of thermal injury compared to an output power of 3 W and, more importantly, using continuous rather than pulsed wave mode significantly increased the extent and depth of thermal injury in rabbit vocal folds.
KeywordsLarynx Vocal fold Laser injury Wound healing Diode laser Endolaryngeal surgery
The authors would like to thank the Sao Paulo Research Foundation (FAPESP) for its financial support and Luciana Almeida Lopes for helping to choose the laser settings. We also thank the Research and Education Center for Phototherapy in Health Sciences (NUPEN) for the laser equipment and technical support.
This study was funded by FAPESP (Fundação de Amparo à Pesquisa de São Paulo—Grant number 2015/25095-0).
Compliance with ethical standards
Conflict of interest
The authors have no conflict of interest to declare.
The study was approved by the Ethics Committee for the Analysis of Research Projects of the University of Sao Paulo School of Medicine (research protocol no. 177/13). All applicable international, national, and institutional guidelines for the care and use of animals were followed.
- 3.Saetti R, Silvestrini M, Galiotto M, Derosas F, Narne S (2003) Contact laser surgery in treatment of vocal fold paralysis. Acta Otorhinolaryngol Ital 23:33–37Google Scholar
- 5.Fanjul M, García-Casillas MA, Parente A, Cañizo A, Laín A, Matute JA et al (2008) Diode laser application for the treatment of pediatric airway pathologies. Cir Pediatr 2008:79–83Google Scholar
- 18.Benninger MS, Alessi D, Archer S, Bastian R, Ford C, Koufman J et al (1996) Vocal fold scarring: current concepts and management. Otolaryngol Head Neck Surg 15:474–482Google Scholar
- 21.Newman J, Anand V (2002) Applications of the diode laser in otolaryngology. Ear Nose Throat J 81:850–851Google Scholar
- 22.D’Arcangelo C, Di Maio FDN, Prosperi GD, Conte E, Baldi M, Caputi S (2007) A preliminary study of healing of diode laser versus scalpel incisions in rat oral tissue: a comparison of clinical, histological, and immunohistochemical results. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 103:764–773CrossRefGoogle Scholar
- 24.Zhang Y, Cao L, Chen Q, Chen X, Xu W, Fang Q et al (2011) Experimental study on different power CO2 laser for vocal cord injury. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 46:1039–1041Google Scholar