Delayed Pneumothorax and Progressive Laryngeal Edema Following Rib-Including Pectoralis Major Osteomyocutaneous Flap for Mandibular Reconstruction in a Patient With Post-Chemoradiation Head and Neck Cancer

We report a rare case of delayed pneumothorax and persistent laryngeal edema following mandibular reconstruction using a rib-including pectoralis major osteomyocutaneous flap in a high-risk post-chemoradiation patient. A 53-year-old cachectic male with a history of chemoradiotherapy for hypopharyngeal carcinoma developed a second primary squamous cell carcinoma of the right buccal mucosa with mandibular invasion. Due to multiple comorbidities and prior radiation, he underwent segmental mandibulectomy and reconstruction using a pectoralis major flap incorporating a vascularized fifth rib segment. The postoperative course was complicated by delayed right-sided pneumothorax requiring chest tube drainage and progressive laryngeal edema requiring tracheostomy and enteral feeding. These complications were likely due to prior irradiation, rib harvesting, and impaired healing. This case demonstrates the feasibility of rib-including pectoralis major flaps for salvage mandibular reconstruction when free-flap surgery is contraindicated, and highlights the importance of prolonged multidisciplinary surveillance of delayed thoracic and airway complications in previously irradiated patients.