Procedure setup. (a) Patient is receiving a nebulizer treatment of 3 mL of 4% lidocaine pre-procedure. (b) Patient positioning and procedure room setup. Note the KTP laser machine on the left side of the room. Both the surgeon and the patient are wearing laser-safe goggles. There are two monitors in the room, one for the surgeon and one for the assistant (the second monitor is outside the picture). [(a) was adapted from Fig. 33.3 in Rosen and Simpson (2008)]
Once the patient is adequately anesthetized, laser precautions should be ensured before the procedure begins. All individuals in the procedure room should wear laser safety goggles. A laser warning sign should be posted outside the door. The KTP laser fiber is first passed through a protective catheter to prevent scratching the inside of the working channel of the laryngoscope (Fig. 7.2). While the surgeon is holding the laryngoscope, the assistant can pass the laser fiber catheter unit through the working channel. The laser fiber is then aimed at the RRP lesions for treatment. Common laser settings include a power of 30 W to 35 W, 15-ms pulse width, and two pulses per second (pps). Total joules and time of laser exposure are recorded for each procedure. The end-tissue effects are also recorded. A 5-point classification system was created describing common end-tissue effects seen during KTP laser treatment (Table 7.1 and Fig. 7.3) (Mallur et al. 2014). The surgeon may start with the most conservative KTP effects and increase as needed. Depending on the location of the RRP lesion, different KTP end-tissue effects are desired. For example, at the anterior commissure, it is preferable to have a treatment effect of KTP 4 on one vocal fold and a KTP 1 on the contralateral vocal fold. This prevents having two raw surfaces contacting each other resulting in anterior glottic web formation. Due to the laryngeal local anesthesia provided, the patient is advised to remain NPO for 2 h after the procedure.
KTP laser fiber-catheter system . The KTP laser fiber is passed through a catheter to prevent scratching the inside of the working channel of the laryngoscope. The entire system is then passed through the working channel. Note the KTP laser fiber past the distal end of the catheter. The KTP fiber length can be easily adjusted during the procedure
The pulsed 532-nm potassium titanyl phosphate (KTP) laser treatment classification
Noncontact, epithelium intact, epithelium blanched
Noncontact, epithelium disruption, slight “craters” in epithelium
Select contact or noncontact, epithelial ablation without tissue removal
Contact, epithelial ablation with tissue removal
Various end-tissue effects from KTP treatment. (a) KTP 1; (b) KTP 2; (c) KTP 3 using contact mode; (d) RRP debris can be removed using flexible grasping forceps through the working channel of a laryngoscope
Office-based pulsed KTP laser treatment of RRP lesions helps patients to avoid multiple general anesthetics as more than one treatment is usually required in this patient population. It allows “touch-up” removal of small RRP lesions. The patient is unsedated; thus he or she can drive to and from the clinician’s office before and after the procedure. In addition, postsurgical recovery time is less compared to those performed in the OR, which translates into less time missed from work or school. Disadvantages include that it is time-consuming for treating bulky RRP lesions and that the treatment is not as precise as when the patient is under general anesthesia. It is also difficult to perform a biopsy and provide KTP laser treatment at the same session due to decreased effectiveness of the laser secondary to bleeding. Complications of office-based KTP laser treatment include vasovagal reaction, epistaxis from passing the laryngoscope through the nose, and anterior glottic web formation.
7.2.2 Operating Room Procedures
Operative microlaryngoscopy has been a long-standing and effective treatment for RRP. This is performed under general anesthesia using principles of phonomicrosurgery (Rosen and Simpson 2008). Patients can typically be intubated with a size 5 endotracheal tube. For those with subglottic or tracheal RRP, jet ventilation or apneic methods can be considered. The largest laryngoscope should be utilized for visualization of the RRP site(s). The laryngoscope may need to be repositioned multiple times during the surgery for optimal exposure of the targeted lesions. Risks of these operating room procedures include those associated with suspension microlaryngoscopy, such as throat pain, jaw pain, tongue swelling, taste change, chipped teeth, and lip or gum lacerations. RRP patients tend to have multiple surgeries; thus there is a risk associated with cumulative general anesthesia as well as vocal fold scarring and anterior glottic web formation. Different surgical techniques are available, and utilization of each technique is dependent on lesion characteristics, equipment availability, and surgeon preference. Specific advantages and disadvantages of each technique are described below.
184.108.40.206 CO2 Laser
CO2 laser has been a traditional treatment for RRP. It has an emission wavelength of 10,600 nm and is absorbed by intracellular water. Therefore CO2 laser , when coupled to an operating microscope, can effectively vaporize RRP lesions with precision, resulting in minimal bleeding. Dedo reported a series of 244 patients with RRP treated with CO2 laser every 2 months (Dedo and Yu 2001). He achieved disease remission in 37% of his patients, disease clearance (no recurrence in 3 years) in 6%, and cure of disease (no recurrence in 5 years) in 17%.
Laser safety precautions are paramount in the OR. The laser beam can reflect off metal from the laryngoscope and injure eyes or skin in it’s path. A misfire may also hit patient tissue(s) that are not protected by a wet towel to absorb the laser energy. In addition, laser smoke, or plume, has been found to contain active viral DNA, which is a potential source of infection (Kashima et al. 1991). In the oxygen-rich environment provided by anesthetic gases, airway fire can be a possibility. Low FiO2 setting (<30%) should be utilized when at all possible. Saline pledgets are placed in the airway to protect the endotracheal tube. The patient’s face is wrapped with wet towels. All OR personnel should wear laser safety goggles. Smoke evacuators are necessary to further reduce laser plume. Laser warning signs are posted outside the OR door. Disadvantage of the CO2 laser includes thermal injury to the surrounding normal tissue, with a theoretical risk of implanting viral particles into those areas. CO2 laser has long been considered a workhorse in otolaryngology. Recent advances in technology including micromanipulators and scanning laser delivery systems have made it into a more powerful operative tool in laryngologic procedures. The use of a CO2 laser requires the laser to be used frequently by the surgeon and well maintained by the laser team at its facility.
220.127.116.11 KTP Laser (pulsed)
Photoangiolytic lasers such as the KTP selectively ablate the papilloma microvasculature with limited thermal injury to the surrounding tissue due to their selective absorption by oxyhemoglobin. KTP was first reported as a treatment modality for RRP during microlaryngoscopy under general anesthesia in 2007 (Burns et al. 2007). This study described 35 procedures performed on 23 patients. Approximately 80% of the cohort achieved more than 90% disease regression with no new laryngeal webbing. Typically KTP laser settings in the OR are the same as office-based settings as described previously. Standard laser safety precautions should apply (see above). KTP end-tissue effects are recorded as described in office-based procedures.
Powered instrumentation for RRP removal first came into use in the early 2000s. Two studies have shown that the microdebrider reduced operative time and caused minimal soft tissue effects (El-Bitar and Zalzal 2002; Patel et al. 2003). Microdebriders allow removal of laryngeal RRP lesions without causing thermal damage. Collection of specimens is available if the tissues are captured in a filtration sock placed on the suction apparatus. The specimens are collected piecemeal rather than en bloc. Nonetheless the tissues obtained through a microdebrider have been shown to be suitable for pathological diagnosis (McGarry et al. 1997), and it is routinely done in endoscopic sinus surgery. There is no plume exposure compared to CO2 laser treatment. In addition, microdebrider has been associated with equivalent postoperative pain and improved voice quality compared to CO2 laser (Pasquale et al. 2003). It may also result in cost savings as expensive laser equipment and personnel are not required. Bleeding intraoperatively can be controlled by submucosal infusion of epinephrine prior to surgical excision or application of epinephrine-soaked pledgets on the surgical site post lesion removal. The smallest microdebrider blade should be used first. The authors typically use a 2.9-mm Skimmer blade (Medtronic®, Minneapolis, Minnesota). The microdebrider should have a starting setting of 500 rpm and can be adjusted accordingly. The microdebrider blade should be held approximately 1–2 mm over the RRP lesion, allowing the suction from the microdebrider to draw the RRP tissue toward the blade and therefore away from the underlying deep tissue. This technique is great for bulky, pedunculated RRP lesions. Its main disadvantage is that the instrument is large in size and sometimes it may obstruct the operative view. When used with great control and good visualization, precision RRP removal can be achieved.