The Lumbar Artery Perforator Free Flap as an Alternative Option for Breast Reconstruction in Low BMI Patients: Analysis of CT Angiography of Donor Sites Across BMI.

Background:  In patients with a low body mass index (BMI), the options for autologous breast reconstruction are limited. With the hypothesis that adipose tissue deposition favors the lumbar region over the abdominal wall, this study sought to investigate the lumbar artery perforator (LAP) flap as an alternative reconstructive option in patients with deficient autologous donor sites consequent to a low BMI.

Methods:  A retrospective cohort analysis was performed, from a prospectively maintained database, of all consecutive deep inferior epigastric artery perforator flap breast reconstructions performed in our unit. A randomized selection of 100 patients with low BMI < 22, normal BMI 22 to 24, and high BMI > 30 was performed. Patient computerized tomography scans were analyzed to measure abdominal wall and lumbar tissue thickness and to define anatomical landmark relations of the LAP.

Results:  A statistically significant difference was identified between the ratio of lumbar-to-abdominal wall thickness between BMI groups, highlighting preservation of the lumbar thickness in patients with low BMI. The mean distance at which the fourth lumbar perforator entered the subcutaneous tissues was 7.7 cm lateral to the spinous process (range 6.4-9.5 cm), with no significant difference between BMI groups, highlighting this consistent anatomical position.

Conclusion:  This study confirms a greater lumbar-to-abdominal wall thickness, therefore volume, in low BMI patients, with consistent lumbar perforator anatomy of 6.4 to 9.5 cm lateral to the spinous process. The LAP flap should therefore be strongly considered for autologous breast reconstruction in this patient cohort.