Objective:
The management of mandibulectomy patients requiring free tissue transfer for reconstruction remains a formidable challenge. Previous work has demonstrated a return to full oral competence and recovery of a pre-operative diet in only a fraction of patients. This study aims to evaluate the factors associated with early and late complications following mandible free flap reconstruction.

Subjects and Methods: This is a retrospective cohort study that included consecutive patients (n=68) undergoing mandibulectomy with subsequent reconstruction using vascularized free tissue transfer at a single institution from 2016-2021. Mandibular defects were categorized according to the Jewer classification, while free flaps were categorized as either osseous or nonosseous (i.e. soft tissue only). Analysis of patient characteristics, surgical variables, complications (early and late), and swallowing outcomes were performed.

Results: The sample was composed of mandibular defects mostly falling into one of three categories: H (n = 22, 32%), LC (n = 18, 26%), or LCL (n = 12, 18%). The majority of reconstructions performed used osseous free flaps (65%) while remaining reconstructions used vascularized soft tissue only (35%). Soft tissue flaps were used to reconstruct the following defects: H (n=18, 63%), L (n=5, 21%), LC (n=1, 4%). The majority (88%) of the soft tissue patients were edentulous.  Additionally, 34% of all reconstructive free flaps were chimeric such that multiple, independent pedicles or perforator vessels were linked to a common source vessel. Overall, 71% of patients recovered some form of an oral diet with 35% achieving 100% PO status. Full oral competence was recovered in 45% of patients and was defined as the absence of anterior spillage or drool with demonstrated full labial closure and intact sucking ability. When stratified by mandibular defect, LCL patients had far greater risk of requiring additional surgeries for hardware or soft tissue complications after 90 days (LCL vs H: 39% vs 5%, p = 0.01). Additionally, LCL patients were less likely to regain 100% PO status compared to either H or LC patients (8% vs 50%, p = 0.02; 8% vs 44%, p = 0.03). A comparison of free flaps demonstrated a substantial increased risk of a complication requiring additional surgery after 90 days in osseous free flaps compared to those with only soft tissue (39% vs 4%, p = 0.002). In addition, soft tissue transfers demonstrated increased return to full oral competence compared to osseous flaps (54% vs 30%, p = 0.045), but no significant differences were seen in other swallowing outcomes. Acute complications (within 30 days) were not significantly different for soft tissue flaps and osseous flaps.  Smoking status, diabetes, prior chemotherapy, and prior radiation therapy did not predict an increased risk of surgical complication or poorer swallowing outcomes.

Conclusion: Osseous flaps for mandibulectomy patients are considered the gold standard for reconstruction but increase the possibility of late complications, often related to hardware extrusion or failure.  When feasible, soft tissue reconstruction of lateral mandibular defects in edentulous patients provides adequate vascularized tissue, avoids many late complications, and allows for improved or equivalent oral and swallowing rehabilitation.