(A658) Volumetric Analysis of Head and Neck Defects and Reconstructive Options

Introduction: There are a remarkable variety of reconstructive options available after excision of head and neck cancer. It can be difficult to select between these options for the many bony and soft tissue defect possible. Much of the existing literature fails to account for individual patient factors which influence tissue thickness and bony stock. This study seeks to pioneer a new method for modeling common head and neck cancer excision defects and determining which bony and soft tissue reconstructive options best meet their individualized needs.

Methods: A retrospective cohort of 47 patients were identified from a database of 521 patients treated for head and neck cancer from 2017-2022 at the University of Pittsburgh Medical Center. Patients were included if they had undergone pre-treatment CT Neck, Chest, and Lower Extremity or PET/CT. Standardized defects including anterior 2/3rds glossectomy and hemimandibulectomy were modeled with the 3D Slicer program. Volume of osseous donor sites including the fibula and scapula as well as musculocutaneous sites including the parascapula, latissimus, anterolateral thigh, and deep inferior epigastric perforator were measured. Donor sites were compared based on their ability to replace native tissue within each subject.

Results: Average hemi-mandibulectomy length was 7.5cm and volume was 17.3cm3. Within each individual, the scapular donor site averaged 72.9% of native mandible volume (SD 19%) and fibular donor site averaged 50% of native mandible volume (SD 22%). Average anterior 2/3rds glossectomy volume was 56cm3 (SD 12.4cm3). With a rectangular template, the latissimus most closely replicated native volume [NTV] (84% of NTV) followed by the parascapular (78% of NTV), ALT (64% of NTV), and deep inferior epigastric perforator flap (142% of NTV).

Conclusions: Modeling head and neck reconstructive defects necessitate individualized pre-operative planning. Selection of optimal donor site tissue maximizes functional and aesthetic outcomes. This study demonstrates that consideration of the scapular and latissimus/parascapular donor sites can improve tissue replacement.