Revisiting Anastomosis to the Retrograde Internal Mammary System in Stacked Free Flap Breast Reconstruction: An Algorithmic Approach to Recipient-Site Selection

Background: The authors present their stacked flap breast reconstruction experience to facilitate selection of either caudal internal mammary vessels or intraflap vessels for the second recipient anastomosis. Methods: A retrospective review was conducted of multiflap breast reconstructions (double-pedicled deep inferior epigastric perforator, stacked profunda artery perforator, and stacked profunda artery perforator/deep inferior epigastric perforator) performed at the authors' institution from 2011 to 2018. Data collected included demographics, recipient vessels used, and intraoperative/postoperative flap complications. Complications were compared between cranial, caudal, and intraflap anastomoses. Results: Four hundred stacked flaps were performed in 153 patients. Of 400 arterial anastomoses, 200 (50 percent) were to cranial internal mammary vessels, 141 (35.3 percent) were to caudal internal mammary vessels, and 59 (14.8 percent) were to intraflap vessels. Of 435 venous anastomoses, 145 (33.3 percent) were to caudal internal mammary vessels, 201 (46.2 percent) were to cranial internal mammary vessels, and 89 (20.5 percent) were to intraflap vessels. Intraoperative revision for thrombosis occurred in 12 of 141 caudal (8.5 percent), 14 of 20 cranial (7 percent), and seven of 59 intraflap (11.9 percent) arterial anastomoses (p = 0.373), and in none of caudal, three of 201 cranial (1.5 percent), and two of 89 intraflap (2.2 percent) venous anastomoses (p = 0.559). Postoperative anastomotic complications occurred in 12 of 400 flaps (3 percent) and were exclusively attributable to venous compromise; seven of 12 (58.3 percent) were salvaged, and five of 12 (41.7 percent) were lost. More lost flaps were caused by caudal [four of five (80 percent)] versus cranial [one of five (20 percent)] or intraflap (zero of five) thrombosis (p = 0.020). Conclusion: If vessel features are equivalent between the caudal internal mammary vessels and intraflap vessels, intraflap vessels should be used for second site anastomosis in stacked flap reconstructions. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.