Long used in a number of medical specialties, lasers offer a minimally invasive way to treat a variety of benign and malignant conditions. Otolaryngology-head and neck surgery is one of the first areas of surgery to successfully employ a number of types of lasers for medical and cosmetic purposes.
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April 2007Using light energy or photons to produce a tissue effect, a laser (which is an acronym for Light Amplification by Stimulated Emission of Radiation), consists of three main components: lasing medium, which is either gas or solid; power or excitation source; and mirrors. Popular perception of lasers in otolaryngology may focus on their cosmetic benefit-to resurface a face, reshape a nose-but lasers are more than smoke and mirrors. Their benefit to treat a wide range of benign and malignant otolaryngological conditions is well documented in many studies that show the superiority of lasers over other surgical techniques in terms of hemostatis and edema, in their potential to reduce wound infection, and in their ability to induce less scarring and improve wound healing because of the minimal damage done to surrounding tissue.
The pulsed dye laser is a safe and effective tool to treat a variety of laryngeal pathology through a flexible laryngoscope in the office without anesthesia. This instrument ushers in…the golden age of laryngology.
-Peter C. Belafsky, MD, MPH, PhD
For many years, the carbon dioxide (CO2) gas laser has been-and it continues to be-the most common type of laser used in otolaryngology. Novel ways to deliver the CO2 laser, as well as completely new emerging technologies, are expanding the possible uses of lasers in this field. As these technologies are increasingly used in office-based practices, the need to educate clinicians about the appropriate clinical applications of lasers as well as safety issues may become more pressing.
CO2 Laser: The Workhorse for Otolaryngologic Procedures
A variety of lasers are currently used in clinical practice, including the Nd Yag [neodymium-doped yttrium aluminum garnet], pulsed KTP [potassium titanyl phosphate], and pulsed dye laser. According to Stanley Shapshay, MD, Professor in the Division of Otolaryngology at Albany Medical College in Albany, NY, the pulsed dye and pulsed KTP are best used for vascular lesions of the larynx and facial plastic surgery (port wine stains and facial telangiectases), and the Nd Yad is used for coagulation of abnormal nasal blood vessels (hereditary hemorrhagic telangiectasia) and photodestruction of low-flow venous malformations of the head and neck as well as destruction of tumors in the airway.
Of all the lasers currently in use, however, the CO2 laser is the most commonly used and remains the standard of care. The CO2 laser is the ‘workhorse’ for the otolaryngologist because of its precise soft tissue interaction with minimal collateral damage, said Dr. Shapshay, adding that it provides for good hemostasis, photocoagulating capillary-sized blood vessels. Other lasers such as the YAG, KTP, and pulsed dye are useful for coagulation; however, they are not as precise as the CO2 laser, which has the best soft tissue interaction of any currently available lasers.
Introduced to the field of otolaryngology in 1972 by Jako and Strong at Boston University, the CO2 laser was first used to ablate respiratory papillomatosis. Since then, the laser has also been used for a variety of head and neck procedures, including excising skin tumors, treating malignancies of the upper aerodigestive tract, treatment for polyps and papillomas in the larynx, capillary hemangiomas in the upper airway, removal of stapes footplate from the middle ear for treatment of otosclerosis, and even for tonsillitis and snoring.
The CO2 laser currently remains the laser of choice for most otolarynatologists, according to Dr. Shapshay.
Refinements to the CO2 Laser
Despite the success of this technology, as well as its availability for more than 30 years, the CO2 laser remains limited because it relies on a direct line of vision of the surgical site. According to F. Christopher Holsinger, MD, of the Department of Head and Neck Surgery at the University of Texas M. D. Anderson Cancer Center in Houston, this is a particular difficulty for head and neck surgeons who are trained in doing operations in open surgical fields. But use of the CO2 laser surgery in the hands of head and neck surgeons across institutions in the United States has expanded significantly over the last ten years-largely based on promising single-institutional studies in Europe, he said.
Improving the ability to deliver the CO2 laser in ways that allow the surgeon to maneuver the laser around a corner or to contour the resection with precise three-dimensional margins will expand the use of the laser in oncologic surgery, said Dr. Holsinger; this would be particularly effective for endoscopic transoral laser resections for laryngopharyngeal carcinomas. To have something that allows the head and neck surgeon to wield the laser as a scalpel is a natural transition from the open surgical approach, he said.
For Dr. Shapshay, improving the use of lasers to treat conditions that include the airway has been a particular concern for quite some time.
For many years, the ‘holy grail’ for those of us using the CO2 laser in the airway has been the development of a suitable fiber to allow CO2 laser transmission in the airway, he said. Up to this point, we have been limited by the lack of a fiber able to transmit this wavelength-particularly in the tracheobronchial area.
Recent development of a photonic bandgap fiber assembly, developed by the OmniGuide Company in Cambridge, MA (www.omni-guide.com ), has led to the development of a novel way to deliver the CO2 laser through a flexible endoscope. Different names are used to describe this assembly, including the CO2 waveguide and the flexible fiberoptic CO2 laser.
Two studies recently presented at the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) annual meeting reported promising results with this new delivery approach. One study, coauthored by Dr. Shapshay, retrospectively analyzed the medical records of 14 patients treated with the CO2 waveguide or pulsed dye laser for lesions in the upper aerodigestive tract (UADT). Most patients were treated for papilloma (n = 8); of these, two patients recurred two months after surgery and two patients had stable papillomas at five months. No perioperative complications were noted, including respiratory distress, dysphonia, or dysphagia.
According to Dr. Shapshay, who is on the Scientific Advisory Board of the Omniguide Company and a paid consultant, this was the first time we were able to deliver the CO2 laser efficiently and safely using a flexible fiber through a flexible fiberoptic laryngoscope.
Further refinements to this laser are currently under development by OnmiGuide, he said. The CO2 laser waveguide needs to be refined for laryngeal applications in the office for benign lesions such as polyps and nodules, he said. In the near future there will be a smaller-diameter fiber with a 250-micron spot size with a suitable aiming light providing higher power density and greater precision.
In another study presented at the AAO-HNS conference, Dr. Holsinger and his colleagues from M. D. Anderson Cancer Center retrospectively analyzed a number of patients treated for a variety of conditions using the newer fiberoptic delivery system. The study found that the flexible fiberoptic CO2 laser had advantages over the older CO2 system for situations with difficult laryngeal exposure, in conservation laryngeal surgery, and for diagnostic biopsy.
We found the flexible fiberoptic CO2 laser to be ideally suited for head and neck oncologic surgery, said Dr. Holsinger. In our hands, it performed equally as well as the line of sight, or free-beam, CO2 laser. It allowed us to use the flexible CO2 laser to get oncologically sound resections with less time.
He also added that it is also expected that use of the flexible laser will reduce patient pain, but prospective analysis of this is still under way.
Although the flexible CO2 laser has been called an emerging technology by some, for Peak Woo, MD, of the Grabscheid Voice Center at Mount Sinai Medical Center in New York, one of the coauthors of the study on the CO2 waveguide with Dr. Shapshay, the flexible CO2 laser is not properly called a new emerging technology. It is not new, he said. It is still CO2 laser surgery-you’re just using a new delivery technology. In that way, the application, although novel, should not be considered radical. The only difference is the method of delivery. The one is through a fibroscope that does not need anesthesia and the other is through an operating microscope, which requires anesthesia.
As an otolaryngologist who deals primarily with head and neck cancer, Dr. Holsinger did clarify that although general anesthesia is indeed not needed with the flexible CO2 laser for many benign lesions of the larynx, and particularly for lesions of the vocal cords such as respiratory papillomas, general anesthesia is required for treatment of malignancy using the CO2 laser.
Pulsed Dye Laser (PDL): The Golden Age of Laryngology
According to Peter C. Belafsky, MD, MPH, PhD, Director of the Center for Voice and Swallowing at the University of California, Davis, a new era of laryngology has begun-and the instrument driving it is the pulsed dye laser (PDL). The pulsed dye laser is a safe and effective tool to treat a variety of laryngeal pathology through a flexible laryngoscope in the office without anesthesia, he said. This instrument ushers in…the golden age of laryngology.
The CO2 laser is the ‘workhorse’ for the otolaryngologist because of its precise soft tissue interaction with minimal collateral damage.
-Stanley Shapshay, MD
With highly vascular selective properties that allow the laser to target blood vessels within the vocal fold while sparing normal laryngeal tissue, the PDL acts as a smart laser, said Dr. Belafsky, adding that its efficacy has been well established in treating a number of laryngeal abnormalities such as laryngeal papilloma, polyps, varices and ectasia, leuoplakia, and dysplasia.
Recent evidence on the efficacy of the PDL was presented at the AAO-HNS conference by Dr. Belafsky and colleagues. In a retrospective analysis of 32 patients who underwent 88 PDL treatments for recurrent respiratory papillomatosis (n = 16), Reinke’s edema (n = 5), vocal fold leukoplakia (n = 3), granuloma (n = 3), polyp (n = 3), varix (n = 1), and vallecular cyst (n = 1), ablation of all visible disease was achieved for the majority of the procedures performed (85%). Early termination of a procedure occurred in 15% of the procedures, largely because a comfortable level of anesthesia was not achieved. Of the 32 patients, 7 (22%) received general anesthesia at least once during their treatment. Overall, the authors concluded that papillomas are easily and safely treated but remain highly recurrent. Reinke’s edema and vocal fold polyps respond very well to the effects of the laser but may require multiple treatments.
[The PDL] is very amenable to use in an unsedated patient through a flexible laryngoscope in the office setting, said Dr. Belafsky. If the patient swallows or coughs during the procedure and the vocal folds move, the laser is unlikely to cause any harm. With a more destructive laser, he added, if the patient coughs or swallows, severe damage could result.
According to Dr. Belafsky, the PDL is currently is still rare in the community but is becoming more widespread among academic centers.
Until more data is available on this technology, however, Dr. Woo feels that the PDL should properly be classified as an emerging technology that needs to undergo proper assessments before it can be considered as standard of care. At this point, he said, the data support it only for consideration as an alternative treatment.
On the horizon for more widespread use may be another emerging cutting-edge laser that Dr. Belafsky and his colleagues at the University of California, Davis Medical Center are currently using to treat a number of conditions, including granulomas, papillomas, airway stenosis, and benign and malignant tracheal neoplasms. Called the Lightforce Gold laser, and manufactured by Medical Energy Inc. (www.medicalenergy.com ), it uses a wavelength of about 980 nm with a very small spot size of 0.1 mm and can be used in a single, multi-, or continuous mode with a wide range of power delivery of 0.1 to 20 watts, said Dr. Belafsky. This laser can be delivered through a very small (1 mm) flexible fiberoptic delivery system that makes it very amenable to in-office surgery through flexible endoscopes, he said.
According to Dr. Belafsky, the laser may also be ideal for frequently performed procedures such as tonsillectomy and adenoidectomy, palate surgery, endoscopic sinus surgery, and turbinate reduction. Because of the precise delivery and limited depth of penetration, preliminary experience suggests that post-tonsillectomy pain may be less with the Lightforce laser, he said. Evidence of this comes from a prospective study he and his colleagues presented at the AAO-HNS meeting, which showed that children treated for tonsillectomy by the 980 nm laser required significantly less postoperative pain medication than those treated with coblation and were able to discontinue narcotic use more quickly than the coblation-treated patients.
Using Lasers in Office-Based Settings
Increasing attention is being focused on using lasers in office-based settings, particularly with the advent of systems that don’t require anesthesia. For Dr. Woo, the demand for the new flexible laser devices and other emerging technology such as the PDL is largely being driven by patients. I think that a large impetus driving this is that the patient does not have to undergo anesthesia, he said, adding that we still don’t know if this new technology will actually benefit patients, say, in terms of saving them money.
For Dr. Belafsky, however, saving money may be one of the advantages of this new technology. Office-based laryngeal surgery has the ability to save the health care system millions of dollars by keeping patients out of the operating room, he said.
One area that may need particular attention as these new flexible devices become more widely used is the need to properly educate clinicians on their clinical application and safety. According to Dr. Woo, training in the original CO2 laser is included in the residency education of otolaryngology residents and includes three levels of training as outlined in the bylaws of the American Society for Laser Medicine and Surgery (ASLMS). These include a didactic portion of the basic science of lasers, a hands-on portion in which residents use the laser in, for example, soft tissue or animals, and a preceptorship in which the resident works with a trained physician to perform laser procedures. A description of procedural skills for using lasers in general surgery can be found on the ASLMS Web site at www.aslms.org/public/standardpsgs.shtml .
For the newer technologies such as the pulsed dye lasers, however, there is little to no regulation on their purchase or use, said Dr. Woo. It is really remarkable that there are no specific federal guidelines, he said, adding that clinicians are often trained in these lasers only through the sales representatives who sell them.
According to Dr. Holsinger, for head and neck surgeons, training is a critical issue. We’re used to doing big operations in an open surgical field, he said. What is clear is that as a head and neck oncologic community, we need to embrace the disciplines of laryngology using the CO2 and other lasers to tackle some of these cancers.
Similarly, it can be quite daunting for clinicians to learn the appropriate application for lasers. Again, according to Dr. Woo, lasers, like all medical devices, are often marketed directly to the user.
For us practicing physicians, we go to a meeting and the instrumentation representative is the main person who tells us what a device is good for and we are then left to figure out what the truth is, he said.
Although technology subsections of societies try to properly assess and recommend the best application of a new emerging technology, he said, there is a period of experimentation with a new device that is not well regulated.
State of the Art
Lasers in otolaryngology-head and neck surgery have been used for many years with a great benefit in treating a variety of benign and malignant conditions. With more than 30 years of use, the CO2 laser remains the workhorse of all the currently available lasers. With more recent novel ways to delivery CO2 through a flexible fiberoptic laser, as well as emerging technology of pulsed dye lasers, both of which have the potential for use without general anesthesia, the use of lasers by otolaryngologists is expected to expand, particularly in office-based settings. With this, training physicians in the use of new laser technologies and the appropriate clinical applications of these technologies will need to be addressed.
©2007 The Triological Society