Fat Necrosis After DIEP Flap Breast Reconstruction: A Review of Perfusion-Related Causes.

[INTRODUCTION] Fat necrosis is a common complication for the deep inferior epigastric perforator (DIEP) flap. A thorough understanding of the factors associated with fat necrosis will aid operative planning for reconstructive surgeons.

[METHODS] A systematic review of the literature was performed between January 1989 and April 2019. Studies were included if they reported on fat necrosis in DIEP flap or evaluated the perfusion of the DIEP flap. Twenty-eight out of 312 studies met the inclusion and exclusion criteria.

[RESULTS] Fat necrosis rates ranged from 12.0 to 45.0% on clinical examination within the literature. The four main perforator-specific factors identified included perforator perfusion zones, perforator location, perforator number and venous congestion. Medial row perforators have a wider perfusion zone, while lateral row perforators have a narrow perfusion zone. Holm zone III has a higher rate of fat necrosis compared to Holm zone II. One to two perforators and more than five perforators and a Type III atypical connection between the superficial and deep venous system had a higher rate of fat necrosis.

[CONCLUSION] The DIEP flap should incorporate between two and three perforators of a substantial calibre; Holm zone III should be excluded if able and careful review of the pre-operative imaging should be performed to analyse the connections between the deep and superficial venous system. There are multiple perfusion-related factors to consider when planning the DIEP flap and ultimately a patient-specific approach to the vascular anatomy is essential.

[LEVEL OF EVIDENCE III] This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .