HSC Section 6 Nov2016 Green Book

Koszewski et al

an office procedure does not preclude subsequent operative intervention. Still, patients with advanced airway compromise or concerning medical comorbidities are not appropriate for treatment in an office setting, and some patients will demon- strate recalcitrant anxiety to these procedures. In our study, all patients without an obvious airway concern were at least offered an office-based procedure; we do not, however, include patients in the present study who were not amenable to office treatment due to the above limitations. Surgical lasers fall into 2 broad categories: cutting/ablating lasers and photoangiolytic lasers. 22 Photoangiolytic lasers, including KTP and PDL, selectively target hemoglobin and are therefore most often used to manage highly vascular lesions. Reinke’s edema is characterized in part by vascular congestion and stasis within the superficial lamina propria. 2,23 While the exact mechanism of the laser-tissue interaction in benign lesions remains under investigation, it is theorized that photoangiolytic laser energy is effective in improving polypoid degeneration by ablating damaged microvasculature within the SLP, ultimately inducing regression of nonvascular pathologic tissue. 24 It has been proposed that localized energy delivery causes a nonspecific inflammatory response, leading to selec- tive and time-dependent expression of inflammatory cytokines such as transforming growth factor beta 1 and cyclooxygenase 2, 25,26 as well as procollagen/collagenase genes such as matrix metalloproteinases. 26,27 These changes are thought to result in favorable alterations in tissue remodeling. As such, in contrast to classical surgical interventions designed to physically remove excessive tissue, laser therapy is thought to induce a favorable biochemical shift—a biological solution for a biolo- gical problem. In our procedures, energy delivery is titrated to a point of superficial blanching of tissues. No immediate reduction of tissue mass is seen; instead, functional improvement is expected after a period of tissue remodeling. In our study, an average of 132 J was delivered per procedure; however, optimal laser settings and energy titration end points remain undefined. Efforts are underway to characterize these para- meters. A recent study examined outcomes for Reinke’s edema as a function of laser parameters and initial treatment effects; the average energy applied was 157 J delivered over a 0.369-second exposure time, and voice outcomes were favorable. 28 In an effort to standardize measurement, a vali- dated classification schema was recently proposed to estab- lish a consistent means for measuring response to the KTP laser. 24,29 The present study adds to this growing body of work beginning to evaluate the relationship between amount of energy delivered and treatment outcome. The patients in our series underwent comprehensive voice analyses before and after completing an intervention, allowing for detailed evaluation of treatment effect. Acoustic measures improved significantly; patients demonstrated improved fre- quency range due to a higher posttreatment maximum funda- mental frequency, representing an improvement in the classic ‘‘low pitched voice’’ reported by many patients. Percent jitter also improved after treatment, perhaps reflecting improved vocal fold symmetry after tissue remodeling. Changes in

aerodynamic parameters were less pronounced. MPT, laryngeal resistance, mean airflow rate, and peak pressure did not signifi- cantly improve following treatment. This may in part be influ- enced by selection bias, as patients with significant airway compromise—and thus, likely, the most abnormal pretreatment aerodynamic profiles—were not offered office procedures. Phonation threshold pressure did, however, improve after treat- ment. Finally, our patients demonstrated improvement in all subcategories of the Voice Handicap Index—functional, physi- cal, and emotional. This perhaps more than other measures sug- gests the utility of these procedures. Some aspects of the present study may require clarifica- tion. First, some individuals showed worsening of certain voice measures after treatment. For example, 1 patient showed increased phonation threshold pressure and airway resistance after a second laser treatment, and 3 patients had decreased MPT after treatment. Also, note that 6 patients underwent multiple procedures. The decision for repeat treatment was based on clinical assessment of recurrent or persistent Reinke’s edema with ongoing dysphonia rather than on objective voice data. While unsedated endoscopic procedures are possible in the majority of patients, anatomic and physiologic limita- tions as well as anxiety-related factors will represent a bar- rier in some patients. Of the 25 procedures presented here, 5 were truncated due to patient intolerance. All patients were active smokers at the time of treatment; it is possible that reactive airway physiology contributed to this high rate of intolerance. Our database did not include which patients ultimately underwent operative interventions, but it is likely that some did. Given this limitation, we are unable to assess voice changes related to subsequent surgical intervention and therefore cannot comment on voice outcomes in these patients. Importantly, no patients required emergent airway intervention during or immediately after the procedure, had significant bleeding, or required hospitalization immediately following the procedure. As such, office-based laser treat- ments in our series were safe. The present study has several important limitations. As a retrospective analysis without a control group, we cannot determine whether the changes in voice parameters observed after treatment were actually due to the interven- tion or simply reflect normal temporal variation of the dis- ease. Second, although this is the largest series of patients undergoing photoangiolytic laser therapy for Reinke’s edema, our sample size is still modest. Further, complete data sets were not available for all patients. This reduced our effective sample size for the pre- and posttreatment analyses and precluded detailed analysis of parameters over longer periods. Finally, our data set did not provide a stan- dardized means for follow-up; as such, patients who devel- oped complications following the conclusion of their procedure may not be included. As office-based procedures become increasingly more common, there are many points for further study. Definition of laser settings to optimize tissue remodeling remains an important and active area of investigation. Prospective

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