Free flap volume changes: can we predict ideal flap size and future volume loss?

Purpose of review Under anticipating free flap volume may lead to deficits in functional and aesthetic outcomes. Alternatively, over anticipating may compromise airway patency, lead to prolonged tracheostomy dependence or poor oral intake, and cause poor cosmetic outcomes. Surgeons face a fine balance in creating a functional reconstruction that accounts adequately for volume changes in the future. Recent findings Recent studies are elucidating the complex and multifactorial volume changes of free flaps that are dependent on postoperative radiation, flap composition, weight fluctuations, and site of reconstruction. Radial forearm free flaps typically lose about 40% of their volume, regardless of patient-dependent variables. Muscle flaps exhibit significant fluctuations with patient-dependent variables. Adipose-prevalent flaps are likely more resistant to radiation effects but are more dependent on postoperative weight changes in the patient. Summary Free flap volume over anticipation recommendations range from 1.1 to 1.4 times the final volume to account for future atrophy but patient characteristics including postoperative radiation, anticipated weight loss, and flap composition should be incorporated into intraoperative decisions for final flap volume.