Preoperative free flap weight estimation from CT angiography
DIEP / TRAMHemi-abdominal flap
PAPTransverse thigh flap
Measured 5 cm lateral to midline at the level of the ASIS
cm
Distance between the skin overlying each ASIS
cm
Pre-operative weight
kg
Estimated Flap Weight
—
Enter all three measurements above
Model: weight (g) = 91.3·x + 36.4·y + 6.2·z − 1030.0 (R² = 0.68, n = 196).
Validated for flap weights of 368–2,808 g. Range shown reflects the study's median percent error (±10.2%).
At the lateral border of the long head of the biceps femoris, 4.5 cm caudal to the inferior gluteal fold
cm
From the inferior gluteal fold to the dominant PAP perforator
cm
Posterior thigh tissue is compressed when supine
Estimated Flap Weight
—
Enter both measurements and the scan position
Model: weight (g) = 77.9·x + 33.8·y + 43.4·z − 254.3 (R² = 0.80, n = 32), where z = 1 supine, 0 prone.
Validated for flap weights of 188–539 g. Range shown reflects the study's median percent error (±10.5%).