Emerging technology: Flexible CO2 laser WaveGuide (2006)

The carbon dioxide (CO2) laser has been a powerful tool in the armamentarium of the otolaryngologist since the early 1970s.1 In the past, rigid endoscopes and the micromanipulator were necessary to reflect a beam along a direct path to the treatment area.2 Exposure of the target area was often difficult and general anesthesia was required to gain access to target areas. Recently, OmniGuide, Inc. (Cambridge, MA) has developed a Photonic Band-Gap Fiber Assembly (PBFA) for delivery of CO2 laser energy.3 This new WaveGuide has the flexibility, maneuverability, and diameter requirements to access lesions and locations that would not be possible using direct visualization. The surgeon is able to apply CO2 laser energy to chosen target lesions in the outpatient clinic through flexible endoscopes. We report our initial experience with the CO2 laser WaveGuide in a case of laryngotracheal amyloidosis. The OmniGuide PBFA consists of an outer cladding encasing a dielectric mirror that surrounds a hollow core.3 The dielectric mirror is composed of alternating layers of low and high refractive index material that act to reflect light into the hollow core. The outer cladding has no optical function but acts as a mechanical support system for the dielectric mirror. The hollow core of the fiber is used as a channel for the laser beam and nitrogen gas flow, which allows for cooling of the fiber and the targeted tissue. In addition, the nitrogen flow cleans the distal end of the WaveGuide and is ideal for identifying the targeted tissue by indenting the tissue. A 74-year-old female with a history significant for 2 prior laryngofissure procedures for laryngeal amyloidosis presented with increasing dyspnea and worsening voice. Her last resection was carried out 4 years ago at another institution. On physical examination her breathing was labored with audible biphasic stridor. Fiberoptic laryngostroboscopy showed supraglottic and subglottic amyloidosis with a laryngeal web. The subglottic amyloidosis extended down the trachea (Fig 2). Imaging of her airway showed submucosal thickening and nodularity extending from the supraglottis to the carina. The decision was made to perform laryngoscopy and bronchoscopy for therapeutic management. Ablated amyloid lesion after CO2 vaporization. The patient was taken to the operating suite and placed under general anesthesia. A Lindholm laryngoscope was placed for exposure and jet ventilation with a Hunsaker catheter was done.4 The laryngoscope was suspended and the operating microscope was used for magnification. Yellow submucosal nodules were noted along the false cords extending into the patients subglottis. Tracheoscopy was performed using a zero degree telescope that showed nodularity throughout the trachea as well as a large nodule along the anterior wall partially obstructing the subglottis. The laser WaveGuide was threaded into the patient's larynx using a malleable suction bovie as a carrier. The laryngeal nodules were ablated and the web was incised. The WaveGuide was then removed from the suction bovie and inserted into a 5-mm rigid bronchoscope (Karl Storz) with the WaveGuide extending 5 mm past the distal end of the bronchoscope (Fig 1).5 The 0° telescope was inserted into the bronchoscope and the complex was placed into the subglottis. The large amyloid mass located on the anterior tracheal wall was ablated (Fig 2). The remaining nodules throughout the trachea down to the level of the carina were partially ablated. The bronchoscope was not used as a means for ventilation but purely as a carrier for the WaveGuide and telescope. Jet ventilation was maintained throughout the procedure using the Hunsaker catheter. Karl Storz bronchoscope with WaveGuide and telescope. Ventilation was achieved using jet ventilation via a Hunsaker catheter in the trachea. The limitation with CO2 laser use in the past has been the need for a direct path of access between the laser and the target tissue. The creation of a flexible CO2 laser fiber WaveGuide greatly increases the ability of the surgeon to access locations that have been considered inaccessible to CO2 laser surgery in the past. This is especially true in the trachea. The laser tissue interaction was similar to conventional CO2 lasers in that 15 to 20 watts gave tissue interaction that was clinically similar to 6 to 10 watts using the micro-manipulator. Furthermore, by adjusting the distance of the probe to the tissue, power density could be adjusted rapidly without the need for changing the focus on the micromanipulator. In addition, the surgeon was able to aim the CO2 laser at angles that would not have been possible using the traditional methods of micro-manipulation. CO2 laser energy can be transmitted using the WaveGuide to targets that do not have a direct path of access between the laser source and target tissue. We report the initial results using the waveguide in a case of laryngotracheal amyloidosis. Although a rigid CO2 laser bronchoscope, tracheoscope or flexible bronchoscope could have been used, the use of the waveguide and telescope delivered through a rigid bronchoscope greatly facilitated the visualization and the speed of removal. By using the rigid bronchoscope and malleable suction bovie as carriers for the WaveGuide, the surgeon is able to gain access to areas of the upper aero-digestive tract and tracheobronchial tree that have traditionally been inaccessible to CO2 laser energy. The ease of manipulation, coagulation properties, and smoke plum evacuation (airflow through the waveguide) allow for an efficient and accurate ablation of lesions in difficult to reach places. This technology provides the surgeon with an effective alternative to dealing with lesions in the upper and lower airway.