Angiogenesis in costal cartilage graft laryngotracheoplasty: a corrosion casting study in piglets.

Abstract

OBJECTIVES/HYPOTHESIS: To investigate the timing and degree of angiogenesis following anterior costal cartilage graft laryngotracheoplasty in an animal model. STUDY DESIGN: Randomized controlled animal model. METHODS: Twelve pigs were included in this study. Three control pigs were perfused with intravascular methyl methacrylate, and overlying tissue was corroded with potassium hydroxide and hydrochloric acid, leaving only a cast of vessels. Nine pigs underwent anterior costal cartilage graft laryngotracheoplasty and were survived for various lengths of time (3 for 48 hours, 3 for 10 days, 3 for 3 weeks) prior to corrosion casting. Transition zones between trachea and cartilage graft as well as the graft itself were analyzed for signs of angiogenesis (budding, sprouting, intussusception) and hypoxic or degenerative vessel features (extravasation, corrugation, circular constriction) using scanning electron microscopy. RESULTS: Angiogenesis peaked above control levels 48 hours after laryngotracheoplasty (P&#x2009;<&#x2009;.0001) and decreased 10 days and 3 weeks following surgery (P&#x2009;<&#x2009;.001, P&#x2009;<&#x2009;.0001, respectively) while remaining elevated above control levels (P&#x2009;<&#x2009;.0001, P&#x2009;<&#x2009;.005, respectively). There was no difference in hypoxic or degenerative features across surgical and control groups. Sprouting angiogenesis dominated over intussusception preoperatively (P&#x2009;<&#x2009;.0001) and 3 weeks following surgery (P&#x2009;<&#x2009;.05). However, there was no difference in type of angiogenesis 48 hours and 10 days following surgery. CONCLUSION: Angiogenesis peaked by 48 hours following costal cartilage graft laryngotracheoplasty and persisted for at least 3 weeks (although decreased) after surgery in this animal model. Hypoxic or degenerative processes did not appear to play a role in tracheal revascularization during the first 3 postoperative weeks.