3D modeling of anterior 2/3rds glossectomy reconstruction: A volume based donor site evaluation.

Objective: Anterior 2/3rds glossectomy results in significant patient morbidity due to speech and swallowing impairment. Microvascular free flap reconstruction compensates for large volume defects. Flap volume is based on the adipose content of the donor site and varies by patient body mass index (BMI) and donor site location. We sought to correlate flap thickness at different donor sites with patient BMI to determine optimal donor site selection.

Methods: Patients with CT scans of the oral cavity, thorax and lower extremity were identified and included. The volumes of the anterior 2/3rds of the tongue were measured and recorded using computed tomography-generated modeling. Pre-muscular tissue thicknesses at anterolateral thigh (ALT), deep inferior epigastric artery (DIEP), latissimus dorsi, and parascapular donor sites were measured. The donor site adequency was defined as reconstructing the tongue volume within 10% of the ideal volume required and stratified based on patient BMI.

Results: In 144 patients, the average anterior 2/3rds glossectomy defect was 100.3 cm. Glossectomy defect size was highly correlated with BMI (p < 0.001). The DIEP flap had the largest volume (155.4 cm), followed by latissimus (105.6 cm), parascapula (97.8 cm), and ALT (60.5 cm). For patients with BMI ≤ 30, the DIEP flap best reconstructed native tongue volume (up to 113 % of native tongue volume). In patients with BMI > 30.1, native tongue volumes were approximated by the latissimus flap (89-92 % of native tongue) and parascapular flap (85-95 % of native tongue volume). In BMI > 30.1 the DIEP flap provided excess tissue bulk (129-135 % of native tongue volume).

Conclusion: The DIEP flap more closely approximates the volume needed to reconstruct anterior two-thirds tongue defects for BMIs ≤ 30. The subscapular system flaps provided the best volume match for BMIs > 30 and the DIEP flap provided excess tissue bulk which could be adjusted in the reconstruction process.