Fat Necrosis in Reconstructed Breast Using Free TRAM Flap

ABSTRACT

Free TRAM flap is considered as the first choice of the breast reconstruction after mastectomy deformity. Complications such as partial flap loss and fat necrosis in reconstructed breasts are less common with free TRAM flap than conventional pedicled TRAM flap or deep inferior epigastric perforator flap(DIEP flap), because free TRAM flap has a robust blood supply by deep inferior epigastric artery. We evaluated the incidence, causes, diagnosis, and treatment of fat necrosis in reconstructed breast using free TRAM flap. A retrospective study was performed in all patients who had undergone free TRAM flap breast reconstruction between 1990 and 2002. Fat necrosis is a clinical diagnosis, usually made by physical examination alone. However we performed mammography and ultrasonography in all patients to rule out the recurrence of tumor, and get the objective and unbiased data. We performed needle biopsy for exclusion of cancer recurrence in selected cases. Of the 92 breasts reconstructed with free TRAM flap, 7 patients(7.6%) had clinically evident fat necrosis, and 2 patients(2.1%) had fat necrosis that was found only by mammography and ultrasonography. The size of fat necrosis in our study was various from 1.0 x 0.7 x 0.5 to 8 x 4 x 3 cm. The lesions of the fat necrosis were usually placed on superomedial and medial part of the reconstructed breast. In case of the fat necrosis, anchoring suture of flap which had been applied for the preservation of flap drooping and ptosis seemed to be related with the location. In addition, use of zone IV of TRAM flap would be associated the occurrence of fat necrosis. We suggest that fixation suture of flap, intraoperative injury of perforator vessel, extensive use of flap (including Zone IV), smoking and obesity, postoperative radiation therapy can be the causes of fat necrosis in the reconstructed breast with free TRAM flap. Fat necrosis is said to be relatively common in patients who were obese or had a history of smoking in literature, but it did not show any significant differences in our study. Five patients underwent excision during nipple-areolar complex reconstruction after 6 months of free TRAM flap breast reconstruction, and 4 patients did not undergo any treatment due to relatively small size. Hardness of fat necrosis became smaller in size, and softened with time. We conclude that the fat necrosis would be decreased if free TRAM flap breast reconstruction was performed with well organized design of flap, sensible assessment of perforators in the flap, careful use of zone IV in thin patient, and careful suture fixation of flap to chest wall.