Classification for animal vocal fold surgery: resection margins impact histological outcomes of vocal fold injury.

OBJECTIVES/HYPOTHESIS Extent of vocal fold injury impacts the nature and timing of wound healing and voice outcomes. However, depth and extent of the lesion created to study wound healing in animal models vary across studies, likely contributing to different outcomes. Our goal was to create a surgery classification system to enable comparison of postoperative outcomes across animal vocal fold wound-healing studies. STUDY DESIGN Prospective, controlled animal study. METHODS Rats underwent one of three types of unilateral vocal fold surgeries classified by depth and length of resection. The surgeries were: for subepithelial injury, resection of epithelium and superficial layer of the lamina propria at the midmembranous portion of the vocal fold; for transmucosal injury, resection of epithelium and lamina propria; and for transmuscular injury, resection of epithelium, lamina propria, and superficial portion of the vocalis muscle. Wound healing was evaluated histologically at various time points up to 35 days postinjury. RESULTS Complete healing occurred by 14 days postsurgery for subepithelial injury, and by day 35 for transmucosal injury. Injury remained present at day 35 for transmuscular injury. CONCLUSIONS Timing and completeness of healing varied by extent and depth of resection. Scarless healing occurred rapidly following subepithelial injury, whereas scarring was observed at 5 weeks after transmuscular injury. The proposed classification system may facilitate comparison of surgical outcomes across vocal fold wound-healing studies. LEVELS OF EVIDENCE N/A.