Late Flap Failure: Etiology and Management

Introduction: Late free flap failure is an unusual setback for patients; the etiology and management are not well described. We investigate associated factors and the management of late failure.

Methods: A single-institution retrospective review of 2,466 free flaps from 2010-2023 for head and neck defects was conducted. Late failure was defined as first detection of ischemic tissue on postoperative day 6 or greater, who went on to have total or partial flap loss. Variables included age, subsite, medical history, complications, day of failure detection, reasons for failure, and treatment. The late failure cohort was then compared to a cohort of 519 patients that had long-term flap survival.

Results: In total 29 patients had late failure (1.2%). Most (86.2%) had total flap failure, while 13.8% had partial flap failure. Oral cavity was the most common subsite (48.3%). In a minority, failure was related to external compression from a hematoma or dehiscence of the anastomosis (13.8%). In most cases, the specific reason for failure was unknown. The most common late failure flaps were anterolateral thigh (27.6%), radial forearm (24.1%), and fibula (20.7%). The average time until detection was 11 days; the flap was detected in the outpatient setting in 43.3%. Patients had two or more reoperations in 69%; rotational flaps were most common (58.6%) followed by a second free flap (31%). In comparing the late failure cohort and the long-term flap survival cohort, late failure patients had a higher proportion of having had at least one pedicle revision (41.4% vs 15.2%, OR = 3.93 [95% CI 1.81 to 8.55]). Late flap failure patients also had comparatively higher rates of postoperative infection (44.8% vs. 12.7%, OR = 5.58 [95% CI 2.57 to 12.12]) and hematoma (24.1% vs. 5%, OR = 6.03 [95% CI 2.36 to 15.41]).

Conclusions: Most patients with late free flap failure require multiple operating room trips for debridement and second flap placement. These patients are often identified in the outpatient setting with already fully necrotic flaps. Patients with late failure are more likely to have had revision of the pedicle, infection, and hematoma.