Thirty-six uncontrolled case-series studies (n=4,259 patients) were included in the review. Six studies (n=759 patients) evaluated complications in both DIEP and free TRAM flap patients. Sample sizes ranged from 10 to 718 patients.
DIEP and free TRAM flap outcomes:
The risk of fat necrosis was significantly higher in DIEP flap patients compared with free TRAM flap patients (RR 1.94, 95% CI 1.28 to 2.93; n=962 patients, five studies, p=0.07 for heterogeneity).
There was no significant difference in the risk of fat necrosis between muscle-sparing free TRAM flaps and full muscle free TRAM flaps (RR 0.91, 95% CI 0.47 to 1.78; n=613 patients, three studies, p=0.58 for heterogeneity).
The risk of flap loss was significantly higher in DIEP patients compared with free TRAM patients (RR 2.05, 95% CI 1.16 to 3.61; n=962 patients, five studies, p=0.04 for heterogeneity).
The risk of abdominal bulge or hernia was significantly lower in DIEP flap patients compared with free TRAM flap patients (RR 0.49, 95% CI 0.28 to 0.86; n=759 patients, five studies, p=0.57 for heterogeneity).
Pooled complication rates:
Pooled flap related complication rates (fat necrosis, total flap loss and abdominal bulge, laxity, or weakness) were higher in DIEP patients. Donor-site morbidity was higher in free TRAM patients.
Publication year analysis:
The cumulative pooled rate of partial flap loss in DIEP flap patients and partial flap loss and total flap loss in free TRAM patients decreased according to publication year.
No evidence of publication bias was found (funnel plot showed symmetry).