Efficacy of superficial inferior epigastric vein superdrainage in free TRAM and DIEP flap: An indocyanine green angiography study of 68 cases.

[BACKGROUND] This study aimed to evaluate the clinical efficacy of venous augmentation using superficial inferior epigastric vein (SIEV) in free transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery perforator (DIEP) flap and investigate the factors that hinder the venous superdrainage.

[METHODS] A retrospective review of 62 free muscle-sparing (MS)-TRAM and 6 DIEP unilateral breast reconstructions from September 2017 to July 2022. Intraoperative indocyanine green angiography was performed on the harvested flap, with the SIEV contralateral to the pedicle side clamped and unclamped for 20 min. The relative ratio of hypoperfused area to the total flap area was calculated and compared quantitatively. The preoperative computed tomography (CT) angiography was reviewed to obtain information on the SIEV diameter and number of midline-crossing medial branches.

[RESULTS] The participants were categorized into three groups: 42 patients in Group 1 (>3% decrease in hypoperfused area), 20 patients in Group 2 (change in hypoperfused area ranging from -3% to 3%), and six patients in Group 3 (>3% increase in hypoperfused area). The mean number of midline-crossing branches (p = 0.002) and mean difference in the diameter of bilateral SIEVs (p = 0.039) were significantly greater in Group 1 than in the other groups.

[CONCLUSIONS] Thirty-eight percent (26/68 cases) resulted in sustained or aggravated perfusion after SIEV superdrainage. Superdrainage using the contralateral SIEV in free MS-TRAM/DIEP flap is recommended when there are more than two midline-crossing medial branches of SIEV and when the caliber of SIEV is relatively greater compared with the pedicle side.