Flexible endoscopic laser surgery on vocal folds How can we minimize thermal damage?

Researchers at Radboudumc have investigated an innovative approach to treating vocal fold lesions using flexible endoscopic laser surgery with local anesthesia, replacing the traditional method that relied on rigid endoscopic surgery under general anesthesia.

Advancements in flexible endoscopy have allowed the procedures of treating vocal fold lesions to shift from the operating room to the outpatient clinic. This offers several benefits, including reducing healthcare costs and improving patient care. During the procedure, patients receive local anesthetics in the nose and throat. A flexible endoscope with a laser guidewire is inserted through the nose, allowing the surgeon to visualize and treat the vocal folds. Afterward, patients can go home the same day, avoiding the need for general anesthesia and long waiting lists for operating rooms. This approach has already proven safe and effective for benign vocal fold lesions, though the potential thermal effects of flexible lasers on delicate vocal tissue had yet to be studied.

Researchers Anouk Schimberg, Gijs Heldens, David Wellenstein, Ruud Verdaasdonk, and Guido van den Broek, under the leadership of Robert Takes and Henri Marres from the Otorhinolaryngology and Head and Neck Surgery Department, have extensively studied the thermal effects of four types of flexible lasers. Their findings, published in Journal of Voice in September 2024, emphasize the importance of minimizing thermal damage to the vocal folds, which could lead to permanent voice disorders.

The study employed a unique thermal imaging technique using a human tissue-mimicking gel. Over 1,100 experiments were conducted, analyzing how different settings—laser power, duration, and fiber distance—affect the surrounding tissue. The research found that laser duration had the greatest impact on thermal expansion and incision depth, stressing that laser exposure should be kept as short as possible to prevent damage.

Building on these results, the team is now investigating whether flexible endoscopic laser surgery could also be effective in treating vocal fold cancer. This study formed part of Anouk Schimberg’s PhD thesis, which she successfully defended in May 2024.

Read the study here

Schimberg AS, Heldens GTN, Klabbers TM, van Engen-Van Grunsven ACH, Verdaasdonk RM, Takes RP, Wellenstein DJ, van den Broek GB. Thermal Effects of CO2, KTP, and Blue Lasers with a Flexible Fiber Delivery System on Vocal Folds. J Voice. 2024 Sep;38(5):1237-1246. doi: 10.1016/j.jvoice.2022.03.006. Epub 2022 Apr 10. PMID: 35418349.