Carotid Blowout Syndrome in Head and Neck Cancer Patients after Free Flap Reconstruction.

Carotid blowout syndrome (CBS) is a rare but potentially fatal complication in head and neck cancer patients who have undergone free flap reconstruction and/or radiotherapy. This review examines CBS, with incidence ranging from 0.5-0.9% in patients treated with modern radiotherapy to 3-4% in postoperative patients, and exceeding 20% in previously irradiated cases. CBS carries high mortality (40-60%) and neurological morbidity (∼60%). The pathogenesis involves arterial wall breakdown due to radiation-induced endarteritis, surgical exposure of vessels, wound complications, and tumor recurrence. CBS is classified as threatened (exposed carotid), impending (sentinel bleed), or acute (active hemorrhage). Diagnosis relies primarily on clinical assessment, computed tomography angiography, and catheter angiography with balloon occlusion testing. Management requires a multidisciplinary approach with immediate stabilization followed by definitive intervention. Treatment options include surgical management (ligation, bypass, flap coverage) and endovascular techniques (deconstructive embolization or reconstructive stent grafting). The endovascular approach has become first-line for many CBS cases, though hybrid approaches combining endovascular stabilization followed by surgical intervention show promise. Despite advancements, prognosis remains guarded with 30-day survival of 70-77% and 1-year survival as low as 32% in patients with active cancer. Rebleeding occurs in 20-40% of cases despite successful initial treatment. Prevention through prophylactic flaps in high-risk cases and early recognition of warning signs are emphasized. A multidisciplinary strategy with timely intervention offers the best chance for improved outcomes in this surgical emergency.