HSC Section 6 Nov2016 Green Book

Annals of Otology, Rhinology & Laryngology 124(2)

Catten 3 described a microflap technique in which a CO 2 laser was used to make a mucosal flap followed by resec- tion or ablation of the aberrant soft tissue between the flap and the cricoid. Shapshay et al 10 reported on the use of radial incisions with a CO 2 laser, followed by dilation with a rigid bronchoscope. Some surgeons favor a cold tech- nique over the laser for making radial incisions. 11 Balloon dilation was introduced in the management of subglottic stenosis as a theoretically less traumatic alternative to passing rigid dilators. 12 In addition to the different surgical techniques, there have been several investigations evaluating wound-healing modulators as adjunctive therapies. Most notable, inhaled, systemic, and locally injected steroids have been used extensively in an attempt to slow restenosis after dilation. 13 Mitomycin C, an alkylating agent, has been proven to pre- vent fibroblast proliferation 14 and has been used with vary- ing degrees of success in endoscopic airway surgery. 15 Halofuginone, an inhibitor of collagen 1-α synthesis, 16 and 5-fluorouracil, an antimetabolite that inhibits fibroblast activity, 17 are also being investigated in animal models as potential adjunctive therapies. Given the variety of options in the endoscopic manage- ment of iSGS, it has become obvious that an objective means by which to quantify operative outcomes and to compare the efficacy of different techniques or adjunctive therapies is sorely needed. In the late 1960s and early 1970s, there was a great deal of interest in using pulmonary function tests (PFTs) to aid in the diagnosis of upper airway obstruction (UAO). Initial investigations focused on identifying values that could differentiate UAO from lower airway disease. 18,19 It was ultimately Hyatt’s 20 description of the flow-vol- ume loop and the different patterns of obstruction (vari- able intrathoracic, variable extrathoracic, and fixed) that provided clinicians with a powerful tool for diagnosing and classifying UAO. There has been a renewed interest in the past 2 decades in using PFT data not only as a diagnostic tool but also as a means of quantifying the results of interventions in UAO. 21,22 This retrospective study is designed to review our experience with using pulmonary function data in the management of patients with iSGS. Specifically, we aim to (1) describe our experience with iSGS, (2) identify which PFT parameters change following endoscopic intervention, (3) quantify the degree of improvement in airflow postoperatively using PFT data, and (4) determine if PFTs change in a predictable manner postoperatively as restenosis invariably occurs. Assessing Outcomes in the Endoscopic Management of Subglottic Stenosis

Methods Inclusion/Exclusion Criteria

This study was approved by the institutional review board at Oregon Health and Science University. A retrospective chart review was performed, examining a single surgeon’s experi- ence with iSGS. Records for all newly diagnosed adult patients with iSGS referred to the senior author between January 1, 2006, and December 31, 2012, were reviewed. At least 1 standard endoscopic intervention (described below) and 1 pulmonary function test was required for inclusion in the study. Patients with a history of previous airway surgery, airway trauma, tracheotomy, positive serology (c-ANCA or ACE level), or intubation within the previous 12 months were excluded from the analysis. Management of Stenosis All patients included in the study were managed endoscop- ically in a standardized fashion. After confirming that the patient could be mask ventilated, anesthesia was induced and maintained using a total intravenous technique. A plas- tic tooth guard was used to protect the maxillary dentition. The airway was exposed using an Osshoff-Pilling laryngo- scope, and the patient was suspended from the Mustard table. Ventilation was conducted via jet technique. Standard laser precautions were used throughout the procedure, to include placing moist gauze pads over the eyes and wet towels over any exposed skin. A 4-mm rod lens telescope was used to evaluate and mea- sure the stenosis. If the initial values were obtained by the resident or fellow, the senior author (J.S.) repeated and con- firmed the measurements. The stenosis was described by its distance below the true vocal folds and by its total length. Once measurements were complete, 2-mm cup forceps were used to take a biopsy. The stenosis subsequently was infil- trated with 1 mL of triamcinolone suspension (40 mg/mL). A CO 2 laser was then used to make 3 to 5 radial incisions in the stenosis. Dilation of the stenosis was performed using a con- stant radial expansion (CRE) balloon. After confirming hemo- stasis and obtaining postoperative photo documentation, a small, cuffed endotracheal tube (5.0) was placed through the laryngoscope. The patient was taken out of suspension and the laryngoscope removed. The patient was then remanded to the care of the anesthesia team for recovery. Patients were dis- charged home from the postanesthesia care unit that same day with a fluticasone inhaler (220 mcg) and instructed to use 2 puffs twice daily until the inhaler was empty. Data Collection and Statistical Analysis After obtaining approval from the institutional review board, the senior surgeon’s operative record was reviewed

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