Lasers in Οtolaryngology: A Laser Odyssey From Carbon Dioxide to True Blue

Abstract

In this special issue of the Ear Nose and Throat (ENT) journal entitled Lasers in Otolaryngology, we attempted to cover and accommodate different experiences from around the globe on both established and some not so well-known techniques and indications for Lasers in most ENT subspecialties. Despite the COVID 19 pandemic, authors from all over the world have expressed their interest in publishing their Laser experiences with ENT journal and for this we are very grateful.

Ever since their invention by Theodore Maiman in 1960, ¹ lasers have been widely used in almost all surgical specialties for treating a wide variety of pathologies. ² It was the development of the CO₂ laser though by Patel in 1963 that is considered to be a milestone in Ear Nose and Throat (ENT) practice, followed by the work of Bredemeier in 1967 on an endoscopic laser delivery system. Jako used this in 1968 to perform a laser-assisted laryngeal operation on a canine. ^{1 -3} Strong’s publication on laser excision of a laryngeal tumor in 1975, as well as studies by other pioneers, such as Jako and Vaughan in the 70s, created a new generation in ENT surgery. ^3,4 Other types have since been developed and used, such as the argon laser, the diode laser, the KTP, the Nd: YAG, the Ho: YAG, the pulsed dye, and the true blue, all of which have been used as an alternative—and sometimes an equal or better solution—to the CO₂.

Shortly after its invention, CO₂ laser was introduced worldwide and is still considered the first choice or an excellent alternative to conventional cold steel dissection, due to its smaller trauma surface, minimal collateral damage, efficient hemostasis, and reduction in postoperative edema and pain. ^1,2

Transoral CO₂ laser microsurgery under anesthesia or in the setting of office laryngology in awake patients has been used for both benign and oncological laryngeal work. ⁵ Early laryngeal carcinoma can be successfully treated both with laser surgery and radiotherapy, yet the latter may have some undesirable long-term side effects, whereas laser cordectomy offers quick recovery and the possibility of second look when healthy margins are in doubt. Better and more accurate staging systems for endoscopic laser cordectomies have meant better understanding and communication between surgeons and pathologists. ⁴ Despite carbon dioxide’s immense popularity though, the same operation can be achieved with other lasers, such as diode laser, KTP, PDL, and Nd: YAG. ^4,5 Different types of lasers offer different tissue manipulation and in some cases have a superior outcome in comparison to the standard CO₂ laser. ⁵ Diode laser, KTP, and PDL cause better photocoagulation and, by extension, better hemostasis. ^2,6,7 Other technical characteristics, such as flexibility and portability, make these lasers preferable and more cost-effective in some cases of laryngeal surgery. ⁵ KTP and PDL are no longer manufactured and more recently a new laser, the so-called true blue, has emerged in laryngeal practice, combining photoangiolytic and cutting properties. This new 445-nm wavelength laser, the so-called “blue laser,” proves to show tissue effects comparable to the KTP laser and is also capable of treating subepithelial vessels, it can coagulate and carbonize at higher energy levels, and can be used via glass fibers in noncontact and contact mode for in-office procedures. ⁸

The application of lasers in the nose began in the late 70s when Lenz firstly used argon laser for inferior turbinate reduction. ³ Ever since, different types of lasers have been used for a variety of nasal pathologies, such as epistaxis, inferior turbinate hypertrophy, nasal and paranasal tumors, skin lesions, and pathologies of the nasopharynx as well. ³ CO₂ laser is rarely used in such operations, due to the fact that the complexity of intranasal anatomy restricts its straight beam direction. ³ Instead, argon laser, diode laser, KTP, Nd: YAG, Ho: YAG, and Er: YAG lases have been used with success. ³ Alibri et al in a systematic review compared the effectiveness of argon, KTP, and diode laser in managing epistaxis caused by hereditary hemorrhagic telangiectasia. ⁹ There was a superiority of argon laser, yet the success of the other 2 systems was not significantly lower in comparison, rendering all of them great tools for the treatment of this disease. ⁹ Argon laser, as well as diode laser, CO₂ laser, KTP, and Nd: YAG, can been used for inferior turbinate reduction. Lippert and Werner compared the biological effects of CO₂ and Nd: YAG lasers in 1997. The direction of CO₂ laser beam only allowed the anterior third of the inferior turbinate to be treated, whereas Nd: YAG could be used for the entire turbinate’s body. CO₂ laser’s postoperative course was better and shorter than Nd: YAG’s and was chosen for the cases of a hyperplastic turbinate head, when all the rest were treated by Nd: YAG laser. ¹⁰ Newman and Anand in 2002 used diode laser for the treatment of the aforementioned pathologies on a small group of patients with relatively good results attributed to great photocoagulation which was achieved by the penetrating depth of this laser. ¹¹ Nasal polyps are also successfully treated by diode laser in contact mode until their complete vaporization is achieved. ¹²

Lasers are also used in otology as a precise cutting tool. External auditory canal stenosis, myringotomy, and stapedotomy may be performed by CO₂, diode, KTP, and argon lasers. ³ In 1980, DiBartolomeo and Ellis suggested that argon laser can be used at either low or high intensity, thus selectively penetrating the target tissue and leaving unharmed the adjacent structures. Lack of vibrations during operation and the previously mentioned features make this laser a great tool for temporal bone microsurgery. ¹³

Oral cavity and oropharyngeal lesions, such as hypertrophic gingivitis, chronic tonsillitis, benign and malignant tumors, or other pathologies have successfully been treated by lasers, such as the CO₂, the KTP, the argon, and the diode laser, offering better hemostasis, reduced postoperative edema, and greater cutting precision than others conventional methods of surgery. ¹²

Lasers are also used in many other fields of otolaryngology including facial plastics and tracheal work and are also robot-friendly and can be used for major robotic laryngeal and oropharyngeal work.

Future innovations in these systems could increase their potential and extend even more their applications in all aspects and subspecialties of ENT surgery. Of course, as with any skill, there is a learning curve and a need for continuous training and recertification for both juniors and seniors, especially as technology is changing rapidly. Lasers are fun to use, but not toys, and the Hippocratic oath “primum non nocere” that is “first do no harm” applies to laser surgery as with any kind of surgical–medical practice.

In this special issue of the ENT journal entitled Lasers in Otolaryngology, we attempted to cover and accommodate different experiences from around the globe on both established and some not so well-known techniques and indications for Lasers in most ENT subspecialties. Despite the COVID-19 pandemic, authors from all over the world have expressed their interest in publishing their Laser experiences with ENT journal and for this we are very grateful!