A prospective study comparing the functional impact of SIEA, DIEP, and muscle-sparing free TRAM flaps on the abdominal wall: Part II. Bilateral reconstruction.

Background: The purpose of this study was to demonstrate the impact of bilateral free flap breast reconstruction on the abdominal wall. This is the second installation of a two-part series. Presented here are bilateral combinations of three techniques: the muscle-sparing free transverse rectus abdominis musculocutaneous (TRAM) flap, deep inferior epigastric perforator (DIEP) flap, and superficial inferior epigastric artery (SIEA) flap.

Methods: A blinded prospective cohort study was performed involving 234 patients. Patients were evaluated preoperatively and for 1 year postoperatively. At each encounter, patients underwent objective abdominal strength testing using the Manual Muscle Function Test and Functional Independence Measure and psychometric testing using the Short Form 36 questionnaire. At postoperative visits, patients also completed a questionnaire specific to breast reconstruction. Statistical analysis included the Kruskal-Wallis, Mann-Whitney, Friedman, and Wilcoxon signed rank tests.

Results: A total of 234 patients were enrolled. Of these, 157 underwent reconstruction, 82 of which were bilateral. There was a significant decline in upper (p=0.02) and lower (p=0.05) abdominal strength from bilateral free TRAM flaps compared with bilateral DIEP flaps. Likewise, there was a significant decline in upper (p=0.055) and lower (p=0.04) abdominal strength from bilateral free TRAM flaps compared with bilateral SIEA flaps. For combinations, the most muscle impairment to least was as follows: free TRAM/free TRAM, free TRAM/DIEP, DIEP/DIEP, DIEP/SIEA, and SIEA/SIEA. The free TRAM/SIEA data were not significant. Although psychometric testing showed trends, there was no significant difference among treatment groups.

Conclusion: Abdominal wall strength following various combinations of bilateral free flap breast reconstruction techniques closely adheres to theoretical predictions based on the degree of surgical muscle sacrifice.