Is Holm Zone III safe from fat necrosis in medial row perforator-based deep inferior epigastric perforator flaps?

Abstract

This study investigated which zonal tissue would be more secure from the risk of fat necrosis between Holm zones II and III and examined the risk factors of fat necrosis in a clinical series of medial row perforator-based deep inferior epigastric artery perforator (DIEP) flaps. A retrospective chart review was performed for patients undergoing unilateral breast reconstructions with medial row perforator DIEP flaps. Data regarding patients, operation-related characteristics, and complications including fat necrosis were collected. Fat necrosis was mainly diagnosed by ultrasound examination, and its location was also assessed. A total of 103 cases were analyzed. Fat necrosis was diagnosed in 13.6% of patients and developed more frequently in zone III (7.8%) than in zone II (4.9%). In risk factor analysis, the inset rate, the weight ratio of the inset flap to harvested flap, was significantly associated with the development of fat necrosis. The flaps with inset rates more than 79% showed 16 times higher risk of fat necrosis than those below 79% in multivariate analysis. The incidence of fat necrosis in zone III was significantly increased in the high inset rate group when compared with the low inset rate group, whereas the incidence in zone II did not change. In unilateral breast reconstruction using medial row perforator DIEP flaps, fat necrosis developed more frequently in zone III than in zone II, and this tendency was more prominent in high inset rate group. Not transferring excessive contralateral tissue including lateral zone III tissue might be helpful for reducing the risk of fat necrosis.