Nature of the Problem and Indications

The development of awake office-based laser procedures has dramatically changed the management of many laryngeal diseases. Such procedures offer several advantages for the patient and surgeon. From the patient perspective, awake procedures are significantly more convenient compared with procedures under general anesthesia or sedation. Patients may leave the hospital on their own and may even return to work the same day. Patient safety is further enhanced by avoiding the risks associated with general anesthesia. This is especially important for patients with significant comorbid medical conditions. Furthermore, certain laryngeal disease entities, such as glottal leukoplakia/dysplasia or papillomatosis, were once observed until severe enough to justify exposing the patient to the inconveniences and risks of general anesthesia. With the advent of effective awake procedures, these diseases can be treated as frequently as indicated by clinician concern and patient symptoms.

Studies have shown that awake laser treatment can be effective in appropriately selected cases of recurrent respiratory papillomatosis, glottal leukoplakia/dysplasia, and vascular lesions. A variety of other lesions, such as vocal fold polyps, granulomas, Reinke edema, and laryngeal amyloidosis, have also been successfully treated.

Preoperative Planning

Patients must be able to tolerate laryngeal visualization without an intense gag reflex. Patients who are not able to remain still for the duration of the procedure, such as those with cervical dystonias or severe head tremor, may be difficult to treat. Anticoagulant or antiplatelet medications should be stopped before procedures if possible; however, in the experience of the authors and others, complication rates are not higher in these patients even if they are unable to stop these medications.

Preparation and Patient Positioning

Most patients tolerate an awake laryngeal procedure; however, patient preparation is essential. The procedure must be clearly explained, including the abnormal sensations produced by topical anesthesia and the potential mild discomfort they may feel during the procedure. It is generally prudent to not attempt a procedure on a patient who seems too anxious to proceed. However, with adequate preprocedure explanations and coaching throughout, even very anxious patients tolerate an awake procedure.

For the purposes of this article, “office-based” implies that the patient is awake, with no or minimal sedation, sitting upright, and able to provide phonatory feedback. Often these procedures are done in hospital-based procedure rooms, such as endoscopy suites as opposed to an “office”; however, as long as there is adherence to these principles the potential advantages of these procedures are still realized.

Excellent laryngeal visualization is essential for successful awake laryngeal procedures. Rod-lens rigid endoscopes generally provide superior image quality compared with flexible fiberoptic endoscopes because of larger and more stable light-carrying fibers. However, the development of flexible endoscopes with a chip-based camera at the distal end of the scope has led to image quality that is almost equivalent to rigid rod-lens scopes. Additionally, adequate anesthesia of the larynx and pharynx is critical to success. Details of this topic have been covered in detail by Wang and Simpson elsewhere in this issue.

Significant hemodynamic changes can be seen during these awake procedures. In a study of 31 patients who underwent close monitoring of their vital signs during their procedure, 23% of patients developed severe hypertension and 29% significant tachycardia. Moreover, none of the patients reported or showed signs of an abnormal level of discomfort. Others studies have reported that most patients tolerate awake procedures with minimal reported pain or discomfort. This may suggest that patients are experiencing significant hemodynamic changes that do not correlate with subjective comfort levels. However, given the low incidence of reported complications with awake procedures, these changes likely do not pose a significant danger to most patients. Therefore, in general, it is the opinion of the authors that monitoring is not routinely indicated in patients who do not receive sedation. However, patients with medical comorbidities, such a severe cardiac or pulmonary disease, may benefit from pulse oximetry or blood pressure monitoring.

Procedural Approach

Laser selection

For awake office-based laser procedures, the laser must be deliverable through a fiber that can be passed through the working channel of a flexible endoscope ( Fig. 1 ). The ideal laser for laryngeal surgery should possess the following properties: superficial penetration, minimal collateral thermal injury, and the ability to cut and coagulate. The commonly described lasers for awake laryngeal surgery are discussed next.

Positioning of the surgeon and the patient for an awake office-based laser procedure.

The carbon dioxide (CO ₂ ) laser has a wavelength of 10,600 nm and its target chromophore is water. The CO ₂ laser was the first laser used for laryngeal surgery. There is a high concentration of water in laryngeal tissue, resulting in rapid dissipation of CO ₂ laser energy without deeper penetration. This allows the laser to cut with minimal collateral thermal injury. The CO ₂ laser was initially developed for mirror reflected line-of-sight surgery, typically with an operating microscope. Its application to awake procedures was limited until the recently developed photonic bandgap fiber assembly (OmniGuide, Cambridge, MA), which allows it to be delivered through a flexible fiber.

The thulium laser has a wavelength of 2013 nm and also has water as its target chromophore, resulting in similar properties to the CO ₂ laser. However, its coagulation capabilities are superior, providing excellent hemostasis. Furthermore, it can be delivered through a small flexible glass fiber, not requiring the expensive fiber required for flexible CO ₂ laser delivery. Finally, the thulium laser can be used in contact and noncontact modes, a distinct advantage in awake laser surgery.

The pulse dye laser (PDL) has a wavelength of 585 nm. Unlike the CO ₂ and thulium lasers, the chromophore is oxyhemoglobin. The proposed mechanism for the PDL is by damage to the walls of microvessels and surrounding perivascular tissue (photoangiolysis) because of its selectivity for oxyhemoglobin. This is thought to ablate a lesion’s blood supply, leading to involution. However, it has also been shown to be effective for nonvascular lesions, suggesting that another mechanism of action is also at play. The PDL can also be used in contact or noncontact mode.

The potassium titanyl phosphate (KTP) laser has a similar wavelength to the PDL at 532 nm and also shares oxyhemoglobin as the target chromophore. The wavelength of the KTP laser is more strongly absorbed by oxyhemoglobin and it has a longer pulse width compared with the PDL. It is theorized that this results in more effective intravascular coagulation and avoids vessel rupture and bleeding that can be encountered when using the PDL. The KTP laser can be used in contact and noncontact modes, and either pulsed or continuous. This latter attribute is useful for hemostatic cutting. However, when used in this setting it has the potential to create more thermal injury when compared with the CO ₂ or thulium lasers.

Postprocedure Care

Awake laser procedures are well-tolerated in patients who have received adequate topical anesthesia. Most patients experience minimal pain, typically do not require any postoperative analgesia, and prefer the awake procedures to procedures done under general anesthetic. Patients are typically discharged immediately after completion of the procedure and are instructed to take nothing by mouth for 30 to 45 minutes after the procedure because of the risk of aspiration secondary to laryngopharyngeal anesthesia.

Potential Complications

Complications rates are very low, with patient mild discomfort during the procedure being the most common complication. It should be emphasized that appropriate laser safety precautions by the surgeon, patient, and other staff involved are essential. Vasovagal reactions can rarely occur, but actual syncope can often be prevented if the prodromal symptoms are recognized. The procedure should be aborted and the patient placed in a reclined position. Koufman and colleagues reported only 1 vasovagal reaction in 406 awake office-based laser procedures. Zeitels and colleagues also reported 2 cases of minor epistaxis in a series of 82 awake laser procedures.

As with any laser laryngeal surgical procedure, there is the risk of inappropriate treatment of normal vocal fold tissue, which may result in scar or permanent worsening of the voice. Care must be taken to use appropriate laser energy settings and to follow the technique described previously to minimize the risk of such injury. Koufman and colleagues did report one case of vocal fold hemorrhage. However, in two large published series there have been no reported cases of significant vocal fold scar or web formation.

Reports of more serious complications are very rare. There has been one report of a laser fiber tip breaking and falling into the distal airway. It was, however, easily retrieved in the awake patient. Mouadeb and Belafsky reported one case of airway distress after treatment of Reinke edema that responded to medical management.

Rehabilitation and Recovery

Voice rest is typically recommended for 1 week. At this point in time, patients are reassessed and if healing is occurring appropriately, they may slowly return to full voice. Patients may require appropriate voice therapy postoperatively to deal with secondary functional voice problems.

Outcomes and Clinical Results in the Literature

Papilloma

The selectivity of the PDL and KTP laser for oxyhemoglobin, combined with the abundant vascular supply to papillomas, has made these lasers very popular in treatment recurrent respiratory papillomas in the office setting ( Figs. 2 and 3 ). Numerous studies have shown that these lasers provide effective and safe treatment for papillomas. Thulium and flexible CO ₂ lasers have also been used for awake treatment of papillomas. Patients presenting with a new diagnosis of recurrent respiratory papillomas should be treated for the first time under general anesthetic, allowing for disease mapping and tissue biopsies. Subsequent procedures can be done in the office setting depending on the amount and extent of disease. The amount of disease that can be treated awake depends on patient tolerance and surgeon experience (see Figs. 2 and 3 ).

The pulsed KTP laser being used to treat recurrent respiratory papillomas of the true vocal folds in noncontact mode. The superficial papilloma ( notice the blanched color ) is treated while avoiding significant bleeding.

The pulsed KTP laser is used to treat papillomas on the true vocal folds in contact mode. The treated superficial papilloma is removed, permitting further treatment of deeper papilloma.