On the Merits of Using Angled Fiber Tips in Office-based Laser Surgery of the Vocal Folds

Office-based endoscopic laser surgery is an increasingly popular option for the treatment of many benign and premalignant tumors of the vocal folds. While these procedures have been shown to be generally safe and effective, recent clinical studies have revealed that there are a number of challenging locations inside the larynx where laser light cannot be easily delivered due to line-of-sight limitations. In this paper, we explore whether these challenges can be overcome through the use of side-firing laser fibers. Our study is conducted in simulation, using three-dimensional models of the human larynx generated from X-ray microtomography scans. Using computer graphics techniques (ray-casting), we simulate the application of laser pulses with different types of laser fibers and compare the total anatomical coverage attained by each fiber. We consider four fiber types: a traditional "forward-looking" fiber - not unlike the ones currently used in clinical practice - and three side-firing fibers that emit light at an angle of 45, 70, and 90 degrees, respectively. Results show that side-firing fibers enable a similar to 70% increase in accessible anatomy compared to forward-looking fibers.