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Using Propensity Score Analysis to Compare Major Complications between DIEP and Free Muscle-Sparing TRAM Flap Breast Reconstructions

Zhong, Toni M.D., M.H.S.; Novak, Christine B. Ph.D.; Bagher, Shaghayegh M.Sc.; Maass, Saskia W. M. C. M.D.; Zhang, Jing M.D.; Arad, Udi M.D.; O’Neill, Anne C. M.D., Ph.D.; Metcalfe, Kelly A. R.N., Ph.D.; Hofer, Stefan O. P. M.D., Ph.D.

Plastic and Reconstructive Surgery: April 2014 - Volume 133 - Issue 4 - p 774–782
doi: 10.1097/PRS.0000000000000024
Breast: Original Articles

Background: Previous studies comparing muscle-sparing transverse rectus abdominis myocutaneous (TRAM) versus deep inferior epigastric artery perforator (DIEP) free flaps have not considered procedure selection bias. Propensity score analysis provides a statistical approach to consider preoperative factors in flap selection, and was used to compare major complications (breast and abdominal) between these microsurgical breast reconstruction (free muscle-sparing TRAM versus DIEP).

Methods: This study evaluated major breast and abdominal complications in 292 consecutive patients (428 free abdominal flaps). Propensity scores were calculated for patient differences affecting flap selection (DIEP versus free muscle-sparing TRAM). Multivariate logistic models using selected covariates separately analyzed breast and abdominal complications between flap methods.

Results: There were 83 major complications (28 percent): breast, 20 percent; abdomen, 8 percent. Using propensity scores, the adjusted odds of abdominal complications were significantly higher in free muscle-sparing TRAM than in DIEP flaps (OR, 2.73; 95 percent CI, 1.01 to 7.07). With prior chemotherapy, body mass index significantly increased abdominal complications (OR, 1.16; 95 percent CI, 1.01 to 1.34). Using propensity scores, there was no significant association between reconstruction method and breast complications; diabetics had significantly increased breast complications (OR, 4.19; 95 percent CI, 1.14 to 15.98). Previous abdominal operations (OR, 1.77; 95 percent CI, 0.96 to 3.30) and immediate reconstruction (OR, 1.86; 95 percent CI, 0.94 to 3.71) approached significance.

Conclusions: Propensity score analysis indicated significantly higher abdominal complications in free muscle-sparing TRAM compared with DIEP flaps. This study highlights the importance of separately evaluating recipient breast and donor abdominal complications and use of propensity scores to minimize procedure selection bias.


Toronto, Ontario, Canada

From the Division of Plastic and Reconstructive Surgery, Department of Surgery and Surgical Oncology, University Health Network; and the Division of Plastic and Reconstructive Surgery and the Lawrence S. Bloomberg Faculty of Nursing, University of Toronto.

Received for publication May 6, 2013; accepted October 18, 2013.

Disclosure: Dr. Zhong is supported by an American Society of Clinical Oncology, Conquer Cancer Foundation Career Development Award, and Dr. Hofer is supported by the Wharton Chair in Plastic and Reconstructive Surgery at the University Health Network. Dr. Hofer, Dr. Metcalfe, and Dr. Zhong are supported by grant funding from the Canadian Breast Cancer Foundation and the Canadian Institutes of Health Research. The other authors do not have a financial interest to declare. None of the authors has a financial interest in any of the products or devices mentioned in this article.

Toni Zhong, M.D., M.H.S., University Health Network, 8NU-871, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada,

©2014American Society of Plastic Surgeons