Synergistic Interactions with a High Intraoperative Expander Fill Volume Increase the Risk for Mastectomy Flap Necrosis

Abstract

PurposeProsthetic-based breast reconstruction is performed with increasing frequency in the United States. Major mastectomy skin flap necrosis is a significant complication with outcomes ranging from poor aesthetic appearance to reconstructive failure. The present study aimed to explore the interactions between intraoperative fill and other risk factors on the incidence of flap necrosis in patients undergoing mastectomy with immediate expander/implant-based reconstruction.MethodsA retrospective review of 966 consecutive patients (1,409 breasts) who underwent skin or nipple sparing mastectomy with immediate tissue expander reconstruction at a single institution was conducted. Age, body mass index, hypertension, smoking status, premastectomy and postmastectomy radiation, acellular dermal matrix use, and application of the tumescent mastectomy technique were analyzed as potential predictors of flap necrosis both independently and as synergistic variables with high intraoperative fill. The following three measures of interaction were calculated: relative excess risk due to interaction, attributable proportion of risk due to interaction, and synergy index (SI).ResultsIntraoperative tissue expander fill volume was high (≥66.7% of the maximum volume) in 40.9% (576 of 1,409 breasts) of cases. The unadjusted flap necrosis rate was greater in the high intraoperative fill cohort than in the low fill cohort (10.4% vs. 7.1%, p=0.027). Multivariate logistic regression did not identify high intraoperative fill volume as an independent risk factor for flap necrosis (odds ratio 1.442, 95% confidence interval 0.973-2.137, p=0.068). However, four risk factors were identified that interacted significantly with intraoperative fill volume, namely tumescence, age, hypertension, and obesity. The SI, or the departure from additive risks, was largest for tumescence (SI, 25.3), followed by hypertension (SI, 2.39), obesity (SI, 2.28), and age older than 50 years (SI, 1.17).ConclusionIn the postmastectomy, hypovascular milieu, multiple risk factors decreasing flap perfusion interact with high intraoperative fill volume to cross a threshold and synergistically increase the risk of flap necrosis.

A Comparison of Elliptical Mastectomy to Inverted-T Pattern Mastectomy in Two-Stage Prosthetic Breast Reconstruction

“…Although this may allow for better skin recruitment, some studies suggest that high intraoperative fill volumes are associated with an increase in perioperative complications, specifically, mastectomy flap necrosis. 9,14 In addition, patients in the inverted-T group demonstrated a higher mean body mass index than the control group (28.7 kg/m 2 versus 26.7 kg/m 2 ; p = 0.04). This would indicate a larger percentage of obese patients in the inverted-T cohort, a factor shown previously to increase complication rates in expander/implant reconstruction.…”

“…3,5,7,8 Variability in reported necrosis rates may depend not only on differences in surgical technique but also on the authors' definition of what constitutes tissue necrosis. 9 Our definition of flap necrosis was all-inclusive, ranging from simple epidermolysis to extensive fullthickness skin loss.…”

Effects of Nitroglycerin Ointment on Mastectomy Flap Necrosis in Immediate Breast Reconstruction

“…These factors were determined a priori based on literature review and surgeon experience and included age older than 65 years, body mass index greater than 30, active smoking, history of preoperative radiation therapy, mastectomy weight greater than 800 g, Wise-pattern incision, nipple-sparing mastectomy, and direct-to-implant reconstruction. [5][6][7][8][9][10][11][12][13] We also performed an exploratory analysis of whether the effect of nitroglycerin varied according to the number of risk factors. A score of 1 was given for each of the aforementioned risk factors.…”

Skin Flap Necrosis After Mastectomy With Reconstruction: A Prospective Study

“…8–15 The literature is inconsistent due to differing definitions of skin flap necrosis and variable patient selection criteria. Studies have shown many factors to be associated with skin flap necrosis including smoking 9,13,14,16 , obesity 8,9,12,14,15,17–19 , incision type 11,20–22 , age 14,16–18 , hypertension 14,18 , tumescence 16–18 , volume of tissue expander fill 17,18 , and larger breasts. 8,23 To address the limitations in the literature, we designed a prospective study to determine the rate of skin flap necrosis after mastectomy with reconstruction and to identify potentially modifiable factors that could improve patient selection and outcomes.…”