(A566) Increased Complications in Immunosuppressed Patients After Microsurgical Head and Neck Reconstruction: A Retrospective Single-Center Study

Introduction: An intact immune system is crucial for proper wound healing. However, the specific effects of immunosuppression on head and neck reconstruction remain unclear. This study aims to assess the effect of immunosuppression on outcomes following microvascular free flap reconstruction of the head and neck.

Methods: A retrospective cohort study was conducted at our institution from 2015-2023 and included patients who underwent head and neck free flap reconstruction (n=86). Immunosuppressed patients, defined as those with HIV, hematologic malignancy, and/or on neoadjuvant immunosuppressant therapy were compared to immunocompetent patients. Primary outcomes included postoperative complications within 90 days and a subgroup analysis was performed to assess differences between the aerodigestive system versus the midface/scalp. Unpaired t-tests were used to assess differences in complication rates between groups.

Results: Thirteen patients (15.1%) were immunosuppressed: 9 (10.5%) patients received immunosuppressant therapy, 4 (4.7%) had a hematologic malignancy, and 3 (3.5%) had HIV. There were no differences in body mass index (BMI), smoking status, or history of radiation between groups. Immunosuppressed patients had higher rates of postoperative infection than immunocompetent patients (p < 0.05). Patients receiving immunosuppressant therapy also had higher rates of major complications than immunocompetent patients, including readmission, reoperation, and flap thrombosis (p < 0.05). A subgroup analysis of free flap reconstruction revealed higher rates of complications in the immunosuppressed group undergoing reconstruction of the aerodigestive system (n=75, 87.2%) but not the midface/scalp (n=11, 12.8%).

Conclusions: Immunosuppressed patients are at higher risk of postoperative infection following free flap reconstruction involving the aerodigestive system. Patients on immunosuppressant therapy are at higher risk of major postoperative complications, and timing between end of therapy and extirpation/reconstruction should be examined.