REVIEW ARTICLE

Effects of Obesity on Postoperative Complications After Breast Reconstruction Using Free Muscle-Sparing Transverse Rectus Abdominis Myocutaneous, Deep Inferior Epigastric Perforator, and Superficial Inferior Epigastric Artery Flap A Systematic Review and Meta-analysis Kyeong-Tae Lee, MD, and Goo-Hyun Mun, MD, PhD Background: Although several studies have found obesity to increase the risk of postoperative morbidity in autologous breast reconstruction, there remains some controversy over the influence of obesity for muscle-conserving abdominal flaps, including muscle-sparing transverse rectus abdominis myocutaneous (msTRAM), deep inferior epigastric perforator (DIEP), and superficial inferior epigastric artery (SIEA) flaps. This review evaluates the effects of obesity on complications in breast reconstruction using muscle-conserving abdominal flaps and compares them to those for conventional free transverse rectus abdominis myocutaneous (TRAM) flaps. Methods: A literature search was conducted using MEDLINE, Ovid, and Cochrane databases for studies reporting complication rates for obese and nonobese patients undergoing breast reconstruction using msTRAM, DIEP, and SIEA flaps and conventional free TRAM flaps. The pooled relative risks (RRs) of the obesity for flap-related and donor complications were estimated in the muscle-conserving flaps by meta-analytic methodology and the pooled complication rates in obese patients were compared between muscle-conserving flaps and conventional TRAM flaps. Here, only those studies following the World Health Organization definition of obesity (body mass index ≥ 30 kg/m2) were included. Results: A total of 17 articles were analyzed. Eight studies were used to compute the obesity-related risks of flap-related and donor complications for msTRAM, DIEP, and SIEA flaps. Obesity increased the risk of total flap loss [RR, 1.68; 95% confidence interval (CI), 0.85–3.33], partial flap loss (RR, 2.26; 95% CI, 1.01–5.02), abdominal bulge or hernia (RR, 1.72; 95% CI, 1.00–2.95), and overall abdominal complications (RR, 1.53; 95% CI, 1.10–2.14). The results of a pooled analysis with 15 studies are consistent with those of the metaanalysis. In comparison to free TRAM flaps, muscle-conserving abdominal flaps showed a lower pooled incidence of flap loss, fat necrosis, and abdominal bulge or hernia in obese patients. Conclusions: This review suggests that obesity increases the risk of both flaprelated and donor-site complications in breast reconstruction using msTRAM, DIEP, and SIEA flaps. In comparison to conventional TRAM flaps, however, muscle-conserving abdominal flaps may have an advantage in reducing the morbidity in obese patients. Key Words: muscle-sparing transverse rectus abdominis myocutaneous flap, deep inferior epigastric perforator flap, superficial inferior epigastric artery flap, obesity, complication, morbidity

Received June 23, 2014, and accepted for publication, after revision, October 26, 2014. From the Department of Plastic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, Seoul, South Korea. Conflicts of interest and sources of funding: none declared. Reprints: Goo-Hyun Mun, MD, PhD, Department of Plastic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-dong 50, Gangnam-gu, Seoul 135-710, South Korea. E-mail: [email protected]. Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0148-7043/16/7605–0576 DOI: 10.1097/SAP.0000000000000400

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B

reast reconstruction for obese patients is a challenging task. It is well known that obesity has adverse effects on postoperative outcomes, and a similar phenomenon has been reported in the field of breast reconstruction.1–6 In particular, prosthesis-based reconstruction for obese patients shows high reconstruction failure rates and catastrophic outcomes,7–9 and therefore autologous tissue reconstruction has been preferred for obese patients.9 Among various options in autologous reconstruction, abdominal flaps are widely used because they provide not only abundant soft tissue for reconstructing large and ptotic breasts, which are common in obese patients, but also acceptable donorsite morbidity. Recently, by virtue of efforts to minimize donor morbidity, muscle-conserving abdominal flaps, including muscle-sparing transverse rectus abdominis myocutaneous (msTRAM) flaps, deep inferior epigastric perforator (DIEP) flaps, and superficial inferior epigastric artery (SIEA) flaps, have been widely used.10–12 Low donor morbidity is considered one of the major advantages of these flaps, but relatively less reliable flap perfusion compared with conventional free transverse rectus abdominis myocutaneous (TRAM) flaps were indicated as their main drawbacks.13–15 There have been some studies reporting a relationship between obesity and adverse outcomes in abdominal flap breast reconstruction.1–6,16,17 Particularly, it was well documented in patients undergoing pedicled16,18 and conventional free TRAM flaps.4,17 On the other hand, conflicting results have been reported for the impact of obesity on complications in patients receiving muscle-conserving abdominal flaps. Some studies of msTRAM or DIEP flaps have demonstrated no significantly increased risk of postoperative complications in obese patients,19–22 whereas other studies showed significantly increased risk in obese patients.6,23 However, most such studies were based on a single institution; thus, a systematic review in conjunction with a meta-analysis may provide a more comprehensive overview of the relationship between postoperative morbidity and obesity in these flaps. The present review estimates the relative obesity-related risk of complications in patients undergoing breast reconstruction with msTRAM, DIEP, and SIEA flaps to evaluate whether these muscleconserving flaps are safe from adverse effects of obesity. In addition, this review computes pooled complication rates for the muscleconserving abdominal flaps and compares them with those for conventional free TRAM flaps to determine which flaps are more suitable for breast reconstruction in obese patients.

PATIENTS AND METHODS Literature Search A literature search was conducted in November 2013 by using MEDLINE, Ovid, and Cochrane databases with the keywords “obesity” Annals of Plastic Surgery • Volume 76, Number 5, May 2016

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Obesity and Microvascular Breast Reconstruction

FIGURE 1. Study attrition diagram.

or “body mass index” (BMI) and “breast reconstruction” and “transverse rectus abdominis myocutaneous,” “TRAM,” “deep inferior epigastric,” “DIEP,” “superficial inferior epigastric artery,” or “SIEA.” A manual search was also conducted to retrieve relevant studies by screening references. A total of 113 studies were obtained after excluding duplicate ones. Then abstracts were reviewed based on predefined inclusion/exclusion criteria. All studies describing complication rates in either obese patients or nonobese patients receiving breast reconstruction with conventional free TRAM, msTRAM, DIEP, or SIEA flaps were included. Postoperative complications were analyzed by classifying them into 2 groups as follows: flap-related and donor-site complications. Flap-related complications included total flap loss, partial flap loss, and fat necrosis, and donor site ones included overall abdominal complications and abdominal bulge or hernia. Studies addressing at least one of the previously mentioned complications were included. Among various definitions of obesity, the World Health Organization

definition (BMI ≥ 30 kg/m2) was chosen for this review, and those studies using other definitions were excluded. Other exclusion criteria included systematic reviews and meta-analyses, case reports, letters, comments, animal studies, and articles in languages other than English. Studies with fewer than 10 patients were excluded for the pooled analysis, but those with fewer than 10 patients in each obesity/nonobesity subgroup were included for the meta-analysis. A total of 77 studies were excluded, and as a result, 36 were reviewed in full and further filtered based on the previously mentioned selection criteria. Studies presenting only the relative risk (RR) of obesity and not allowing for calculating the incidence of complications were excluded. When 2 or more studies were from the same institution with overlapping study period, they were considered as the same project and only 1 article with the largest number of cases or showing the most detailed data was chosen. Studies describing only combined data from muscle-conserving abdominal flaps with other types of flaps (including conventional free

TABLE 1. Characteristics of Studies Comparing Outcomes in Obese and Nonobese Patients Included Studies

Guerra et al, 2004 Garvey et al, 2005 Wan et al, 2010 Bailey et al, 2010 Schrey et al, 2010 Seidenstuecker et al, 2011 Ochoa et al, 2012 Fischer et al, 2013

No. No. Patients Flaps

140 71 418 15 12 558 418 812

Flap Types

Bilateral Mean BMI, Reconstruction, % Mean Age, y kg/m2 Obesity, % Smoker, % DM, % HTN, %

280 DIEP 80 DIEP 554 msTRAM DIEP 17 DIEP 13 msTRAM DIEP 624 msTRAM DIEP 638 DIEP 1258 msTRAM DIEP SIEA

100 12.7 32.5 13.3 8.3 11.8 52.9 58.6

49 53.6 50.1 45.9 49.8 NA 50.4 50.0

27 26.2 26.6 28.5 26.7 NA 28.3 28.4

20 16.9 21.8 26.7 25 14.2 39.5 33.5

18.6 5.6 NA NA NA 16.8 8.1 13.4

NA NA NA 0 NA NA 5.0 7.4

NA NA NA 20 NA NA 25.8 26.7

DM indicates diabetes mellitus; HTN, hypertension; NA, not applicable.

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TABLE 2. Studies Reporting Complication Rates in Obese Patients Flap-Related Complications Included Studies

No. Patients No. Flaps

Guerra et al, 2004 Garvey et al, 2005 Wan et al, 2010 Momeni et al, 2011 Seidenstuecker et al, 2011 Garvey et al, 2012 Ochoa et al, 2012 Fischer et al, 2013

28 12 77 28 79 NA 165 272

56 15 NA 42 89 548 258 428

Donor-Site Complications

Total Flap Partial Flap Fat Abdominal Bulge/ Overall Abdominal Loss, % Loss, % Necrosis, % Hernia, % Complication, %

Flap Types

DIEP DIEP msTRAM DIEP msTRAM DIEP SIEA msTRAM DIEP msTRAM DIEP SIEA DIEP msTRAM DIEP SIEA

0 0 NA 0 3.4 1.5 1.2 1.6

5.4 NA NA 0 3.4 3.8 NA 0.7

10.7 6.7 NA 9.5 NA 6.9 9.3 4.0

3.6 16.7 NA 7.1 1.3 NA 1.8 5.9

50.0 50.0 13.0 14.3 6.3 NA 33.3 12.1

NA indicates not applicable.

on the number of flaps. A meta-analysis was conducted using RevMan5.2 to estimate the RR with 95% confidence intervals (CIs) based on the Mantel-Haenszel test. The heterogeneity of outcomes of each included study was assessed using I2 statistics. When I2 ranged from 0% to 30%, the analyzed study was considered to have nonsignificant heterogeneity, and a fixed-effects model was used to pool weighted data. Otherwise, a random-effects model was used. Forest plots were used to present the results, and funnel plots were generated to assess publication bias.

TRAM or nonabdominal flaps) and missing extractable data for each type of flap were excluded from the analysis. On the basis of the full article reviews, a total of 17 studies were eventually analyzed (Fig. 1).

Data Extraction On the basis of the guidelines of the Meta-analysis of Observational Studies in Epidemiology statement for reporting a metaanalysis,24 the following data were extracted: the first author; the publication year; the institution; the study period; the number of patients; the number of flaps; the rate of bilateral reconstruction; the mean age of patients; the mean BMI; rates of smoking, diabetes, and hypertension; the number of patients with abdominal bulge or hernia; the number of any kind of abdominal postoperative complication; the number of total and partial flap loss; and the number of flaps with fat necrosis.

RESULTS Study Characteristics All 17 studies in this meta-analysis were uncontrolled case series. Among these, 15 presented data for msTRAM, DIEP, or SIEA flaps, and 8 of these 15 described complication rates for both obese and nonobese patients and thus were considered for estimating the RR20,21,23,25–29 (Table 1). Four studies presented data only for DIEP flaps20,21,28,29; 3, for msTRAM and DIEP flaps25–27; and 1, for

Statistical Analysis The incidence of abdominal complications was calculated based on the number of patients, and that of flap-related complications, based

TABLE 3. Studies Reporting Complication Rates in Nonobese Patients Flap-Related Complications Included Studies

Guerra et al, 2004 Garvey et al, 2005 Cheng et al, 2006 Holm et al, 2006 Takeishi et al, 2008 Bailey et al, 2010 Wan et al, 2010 Elliott et al, 2011 Seidenstuecker et al, 2011 Ochoa et al, 2012 Fischer et al, 2013 Kim et al, 2013

Donor-Site Complications

No. Patients

No. Flaps

Flap Types

Total Flap Loss, %

Partial Flap Loss, %

Fat Necrosis, %

Abdominal Bulge/ Hernia, %

Overall Abdominal Complication, %

112 59 73 15 NA

224 65 74 17 91

DIEP DIEP msTRAM DIEP DIEP msTRAM

0 4.6 0 0 0

0.9 NA 2.7 0 NA

12.9 9.2 13.5 29.4 3.3

3.6 10.2 0 NA 2.2

41.1 39.0 2.7 NA NA

11 277 45 479

12 NA NA 535

DIEP msTRAM DIEP msTRAM msTRAM DIEP

0 NA 0 0.4

8.3 NA NA 1.3

16.7 NA 6.7 NA

NA NA 2.2 2.7

NA 6.5 NA 5.4

253 540

380 830

DIEP msTRAM DIEP SIEA

0.8 1.2

NA 0.5

10.3 3.6

1.2 2.4

27.7 3.9

100

100

DIEP

0

0

6.0

NA

NA

NA indicates not applicable.

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FIGURE 2. Forest plot comparing the incidence of total flap loss between obese and nonobese group.

msTRAM, DIEP, and SIEA flaps.23 These studies were also included for the summarization of pooled complication rates except for 1 with fewer than 10 patients in each subgroup. The other 7 studies9,19,30–34 (2 presenting data only for obese patients6,9 and 5, only for nonobese patients30–34) were use) for the pooled analysis (Tables 2 and 3). As a result, a total of 14 studies were suitable for the calculation of pooled complication rates for muscle-conserving abdominal flaps. For computing the pooled incidence of complications for conventional free TRAM flaps, the remaining 2 studies4,17 describing complication rates only for free TRAM flaps and 1 study25 with extractable data for conventional TRAM flaps from combined data were included.

A Meta-analysis of Studies Comparing Obese and Nonobese Patients for Muscle-Conserving Abdominal Flaps Eight studies representing 640 obese and 1740 nonobese patients were analyzed. There was a trend toward an increased risk of total flap loss in obese patients (RR, 1.68; 95% CI, 0.85–3.33; fixed-effect model, I2 = 28%) (Fig. 2). The risk of partial flap loss in obese patients was approximately 2.3 times higher than that in nonobese patients (RR, 2.26; 95% CI, 1.01–5.02; fixed-effect model, I2 = 0%) (Fig. 3). The reported incidence of total and partial flap loss was extremely low and thus was further analyzed by considering only a single category of any flap loss. There was a 2.43-fold increase in the risk of any flap loss in obese patients (95% CI, 1.19–4.95; random-effect model, I2 = 35%) (Fig. 4). There was no increase in the risk of fat necrosis in obese patients (RR, 0.95; 95% CI, 0.69–1.32; fixed-effect model, I2 = 0%) (Fig. 5). In the meta-analysis of abdominal bulge or hernia, obese patients showed a 1.72-fold increase in the risk than nonobese patients (95% CI,

1.00–2.95; fixed-effect model, I2 = 0%) (Fig. 6). The risk of overall abdominal complications was also significantly higher in obese patients than in nonobese patients (RR, 1.53; 95% CI, 1.10–2.14; randomeffect model, I2 = 57%) (Fig. 7).

Pooled Complication Rates for Obese and Nonobese Patients for Muscle-Conserving Abdominal Flaps Overall, the results of the pooled analysis are consistent with those of the meta-analysis. The pooled incidence of total flap loss in obese patients was approximately 1.9 times higher than that in nonobese patients (1.5% vs 0.8%). The rate of partial flap loss in obese patients was 2.6% and almost 3 times higher than that in nonobese patients (0.9%). The incidence of any flap loss was 2.1 times higher in obese patients than in nonobese patients (4.5% vs 2.1%). The rate of fat necrosis in obese patients was 6.8% and was slightly lower than that in nonobese patients (7.3%), which was also consistent with the result of the meta-analysis. The incidence of abdominal bulge or hernia in obese patients was 4.3% and approximately 1.7 times higher than that in nonobese patients (2.6%). The rate of overall abdominal complications was approximately 1.7 times higher in obese patients (19.2%) than in nonobese patients (11.5%) (Table 4).

Comparison of Complication Rates for Obese Patients Between Muscle-Conserving Abdominal Flaps and Conventional Free TRAM Flaps Sixteen studies including 13 of muscle-conserving abdominal flaps, 2 of conventional free TRAM flaps, and 1 presenting combined data of conventional free TRAM flap, msTRAM, and DIEP flaps were analyzed. Neither total nor partial flap loss was analyzed separately because of the insufficient number of studies with data for each type of

FIGURE 3. Forest plot comparing the incidence of partial flap loss between obese and nonobese group. © 2014 Wolters Kluwer Health, Inc. All rights reserved.

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FIGURE 4. Forest plot comparing the incidence of any flap loss between obese and nonobese group.

loss, and analysis was conducted for the following 4 categories: any flap loss, fat necrosis, abdominal bulge or hernia, and overall abdominal complications. First, for pooled complication rates for total patients (both obese and nonobese patients), muscle-conserving abdominal flaps had higher rates of flap-related complications including any flap loss and fat necrosis but lower donor morbidity than conventional free TRAM flaps, which is consistent with the findings of previous studies.13–15,35 By contrast, in the comparison of pooled complication rates for obese patients, muscle-conserving abdominal flaps showed a lower incidence of all types of complications except for overall abdominal complications. The pooled incidence of any flap loss in free TRAM flaps was 5.6%, which was higher than that in msTRAM, DIEP, and SIEA flaps (4.5%) and similar results were also observed for fat necrosis (7.6% vs 6.8%) and abdominal bulge or hernia (5.6% vs 4.3%). Meanwhile the pooled incidence of overall abdominal complications was higher for muscle-conserving abdominal flaps (19.2%) than for free TRAM flaps (18.9%), although the difference was not large (Table 5).

Assessment of Publication Bias Figure 8 shows a funnel plot for total flap loss, and Figure 9, that for abdominal bulge or hernia. These plots are relatively symmetric, suggesting the possibility of any publication bias to be low.

DISCUSSION So far, the studies investigating the adverse effect of the obesity in autologous tissue breast reconstructions were mainly regarding pedicled or conventional free TRAM flaps.1–4,16–18,36 On the contrary, few

large-scale studies or meta-analyses of adverse effects of obesity have specifically focused on muscle-conserving abdominal flaps, including msTRAM, DIEP, and SIEA flaps. Some single-institution studies of these flaps have shown no significant difference in postoperative morbidity between obese and nonobese patients.20,21 The results of the present meta-analysis did not support these findings, showing an increased risk for all types of complications in obese patients. In addition, the incremental increase in the risk was significant for partial flap loss, any flap loss, abdominal bulge or hernia, and overall abdominal complications. Interestingly, these results are also consistent with the results of the pooled analysis. As the patients placed in both extreme were included in each subgroup for pooled analysis, for instance, morbidly obese patients in obese group and normal or underweight patients in nonobese group, differences in pooled complication rates between obese and nonobese patients were even more pronounced than those in the meta-analysis. In any case, it seems obvious that the risks of morbidity increased in obese patients receiving muscle-conserving abdominal flaps. In the present review, total or partial flap loss was more frequently observed in obese patients. Obesity was frequently combined with other medical morbidities such as hypertension, diabetes, hyperlipidemia, and other cardiopulmonary diseases,23,36 which can impede microvascular hemodynamics and eventually flap survival, and therefore, it is difficult to conclude that the high rate of flap loss is attributable solely to negative effects of obesity. However, it is clear that the rate of flap survival was lower in obese patients, although the overall success rate was high. Previous studies have suggested several mechanisms, including relatively low flap salvage rates,4 perforators stretched and attenuated by heavy flaps,4 increased pedicle tension,23 and a high rate of

FIGURE 5. Forest plot comparing the incidence of fat necrosis between obese and nonobese group. 580

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Obesity and Microvascular Breast Reconstruction

FIGURE 6. Forest plot comparing the incidence of abdominal bulge or hernia between obese and nonobese group.

thrombosis.23 This suggests a need for better solutions to these problems, including solid anchoring sutures when insetting flaps, harvesting long pedicles as much as possible, meticulous anastomosis, and thorough flap monitoring. In addition, according to an animal study of this topic, abdominal flaps in obese subjects showed decreased baseline energy stores and ultimately reduced dimension of viable flaps.37 This suggests that impaired flap survival may be due not to the aforementioned technical problems but to inherent characteristics of flaps in obese patients. To overcome this, it may be appropriate to delay reconstruction until a sufficient reduction in preoperative weight is achieved within an extent that does not interrupt oncological treatment. Besides, as a way to compromise, not transferring excessively large flaps may be a solution for reducing the rate of partial flap loss in obese patients. According to the present review, the risk of donor morbidity increased significantly in obese patients receiving muscle-conserving abdominal flaps, which was similar with those receiving pedicled and conventional free TRAM flaps.4,16,17 A large donor wound and impaired wound healing in obese patients are considered to contribute to increased risk of abdominal complications. In terms of abdominal bulge or hernia, most of the studies considering muscle-conserving abdominal flaps showed a similar or nonsignificant increased risk in obese patients,20,21,26,28 but the risk also increased significantly for muscleconserving abdominal flaps according to this review. This suggests that surgeons should pay more attention to meticulous donor-site repair even in muscle-conserving abdominal flaps in obese patients to mitigate postoperative complications.

Above all, despite adverse effects of obesity, excellent outcomes of breast reconstruction using muscle-conserving flaps in obese patients would be noteworthy. The pooled incidence of flap failure was less than 2% in obese patients, and that of abdominal wall weakness was less than 5%. This suggests that, with proper preoperative planning and meticulous surgical procedures, muscle-conserving abdominal flaps are likely to be the first-line option in breast reconstruction for obese patients. The results of the comparison of pooled complication rates for obese patients between muscle-conserving abdominal flaps and conventional free TRAM flaps are also interesting. Little has been known about which flap is more appropriate for breast reconstruction in obese patients. In fact, prospective studies comparing the groups having homogenous characteristics except for the type of flap in obese patients may be ideal, but few studies trace this design. In this regard, an indirect comparison like this review may be helpful. In the present study, muscle-conserving abdominal flaps showed a lower pooled incidence in obese patients across all types of complications except for overall abdominal complications than conventional free TRAM flaps. In particular, flap-related complications were less frequent in obese patients receiving muscle-conserving abdominal flaps than in those receiving free TRAM flaps, although the flap complication rates for total patients including obese and nonobese were higher in muscle-conserving flaps. Although the differences were not large and it is unclear whether they led to some clinical significance, muscle-conserving abdominal flaps are likely to be at least comparable or even safer than conventional free TRAM flaps in terms of flap-related complications and abdominal wall

FIGURE 7. Forest plot comparing the incidence of overall abdominal complications between obese and nonobese group. © 2014 Wolters Kluwer Health, Inc. All rights reserved.

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TABLE 4. Pooled Complication Rates of Obese and Nonobese Patients Obese Postoperative Complications

Flap-related complication Total flap loss Partial flap loss Any flap loss Fat necrosis Donor-site complications Abdominal bulge/hernia Overall abdominal complication

Nonobese

No. Studies Total Subjects Pooled Complication Rate, % No. Studies Total Subjects Pooled Complication Rate, %

8 6 6 8 6 7

Total flaps 1441 1168 1168 1356 Total patients 584 661

weakness in obese patients. Therefore, the muscle-conserving abdominal flaps may be suggested as primary options of breast reconstruction for obese patients in preference to conventional TRAM flaps, although further well-designed studies would be required for obtaining more solid conclusions regarding this topic. One of the limitations of this review is the potential issue of heterogeneity in characteristics of msTRAM, DIEP, and SIEA flaps, which were analyzed as a single group. These flaps can have different characteristics, and therefore their obesity-related impacts can vary, resulting in biased observations. However, although many studies reported significantly different complication rates between conventional TRAM flap and DIEP flaps,14,15,35 recent meta-analysis studies demonstrated that no statistically significant difference was observed between msTRAM flap and DIEP flap.35,38 Regarding SIEA flaps, although they were considered to develop less donor-site morbidity generally,39–42 some studies showed no significantly different rate of abdominal bulge or hernia between SIEA flaps and msTRAM or DIEP flaps.39,40 Because of such mixed results, these flaps were analyzed as a single group of muscle-conserving abdominal flaps in the present review. Here, no significant heterogeneity was observed except for overall abdominal complications, although the proportion of these flaps varied across studies. Nonetheless, further analysis adjusting potential confounding effects derived from different types of flaps used would be required for obtaining more robust conclusions.

1.5 2.6 4.5 6.8

10 8 8 9

4.3 19.2

7 7

Total flaps 2328 1792 1792 1802 Total patients 1561 1793

0.8 0.9 2.1 7.3 2.6 11.5

Another limitation of this review involves the limited evidence levels of the included studies. All included studies were retrospective case series, which may weaken the strength of this review. Because of the uncontrolled study design and a lack of extractable data, it was not possible to adjust the effects of other risk factors for complications such as patient comorbidity and bilateral reconstruction. Furthermore, although not a few studies have reported adverse effects of obesity in autologous breast reconstruction, definitions of obesity tend to vary widely across studies and some not using the World Health Organization classification were excluded from this review for unification of the analysis. Despite these limitations, however, this review provides the first meta-analysis based on a considerable number of obese patients to evaluate the effects of obesity in the muscle-conserving abdominal flaps, namely msTRAM, DIEP, and SIEA flaps.

CONCLUSIONS This review demonstrated that obesity increased the risk of both flap-related and donor complications in breast reconstruction using msTRAM, DIEP, and SIEA flaps. In comparison to conventional free TRAM flaps, muscle-conserving abdominal flaps can provide decreased risk of abdominal bulge or hernia without added risks of flaprelated complications in obese patients. Although muscle-conserving

TABLE 5. Comparison of Pooled Complication Rates of the Obesity Between Conventional Free TRAM Flap and Muscle-Conserving Abdominal Flap Complication Rate, % Complications

No. Studies

Flap-related complication Any flap loss Free TRAM flap msTRAM, DIEP, SIEA flap Fat necrosis Free TRAM msTRAM, DIEP, SIEA flap Donor-site complications Abdominal bulge/hernia Free TRAM msTRAM, DIEP, SIEA flap Overall abdominal complication Free TRAM msTRAM, DIEP, SIEA flap

582

Total Subjects

Obese

Nonobese

Total

Total flaps

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2 9

1505 2960

5.6 4.5

2.0 2.1

2.4 3.1

2 12

1505 3158 Total patients

7.6 6.8

5.5 7.3

5.7 7.1

2 8

1218 2145

5.6 4.3

4.1 2.6

4.3 3.0

2 8

773 2454

18.9 19.2

13.9 11.5

14.5 13.6

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FIGURE 8. Funnel plot of direct comparison meta-analysis for total flap loss.

FIGURE 9. Funnel plot of direct comparison meta-analysis for abdominal bulge or hernia.

abdominal flaps may not be completely free from detrimental effects of obesity, they can be considered a first-line option for autologous breast reconstruction in obese patients. REFERENCES 1. Paige KT, Bostwick J 3rd, Bried JT, et al. A comparison of morbidity from bilateral, unipedicled and unilateral, unipedicled TRAM flap breast reconstructions. Plast Reconstr Surg. 1998;101:1819–1827. 2. Berrino P, Campora E, Leone S, et al. The transverse rectus abdominis musculocutaneous flap for breast reconstruction in obese patients. Ann Plast Surg. 1991;27:221–231. 3. Kroll SS, Netscher DT. Complications of TRAM flap breast reconstruction in obese patients. Plast Reconstr Surg. 1989;84:886–892. 4. Chang DW, Wang B, Robb GL, et al. Effect of obesity on flap and donor-site complications in free transverse rectus abdominis myocutaneous flap breast reconstruction. Plast Reconstr Surg. 2000;105:1640–1648. 5. Vyas RM, Dickinson BP, Fastekjian JH, et al. Risk factors for abdominal donorsite morbidity in free flap breast reconstruction. Plast Reconstr Surg. 2008;121: 1519–1526. 6. Jandali S, Nelson JA, Sonnad SS, et al. Breast reconstruction with free tissue transfer from the abdomen in the morbidly obese. Plast Reconstr Surg. 2011; 127:2206–2213. 7. McCarthy CM, Mehrara BJ, Riedel E, et al. Predicting complications following expander/implant breast reconstruction: an outcomes analysis based on preoperative clinical risk. Plast Reconstr Surg. 2008;121:1886–1892. 8. Atisha DM, Alderman AK, Kuhn LE, et al. The impact of obesity on patient satisfaction with breast reconstruction. Plast Reconstr Surg. 2008;121:1893–1899.

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Obesity and Microvascular Breast Reconstruction

9. Garvey PB, Villa MT, Rozanski AT, et al. The advantages of free abdominalbased flaps over implants for breast reconstruction in obese patients. Plast Reconstr Surg. 2012;130:991–1000. 10. Chang DW. Breast reconstruction with microvascular MS-TRAM and DIEP flaps. Arch Plast Surg. 2012;39:3–10. 11. Blondeel PN. One hundred free DIEP flap breast reconstructions: a personal experience. Br J Plast Surg. 1999;52:104–111. 12. Holm C, Mayr M, Hofter E, et al. The versatility of the SIEA flap: a clinical assessment of the vascular territory of the superficial epigastric inferior artery. J Plast Reconstr Aesthet Surg. 2007;60:946–951. 13. Bonde CT, Christensen DE, Elberg JJ. Ten years' experience of free flaps for breast reconstruction in a Danish microsurgical centre: an audit. Scand J Plast Reconstr Surg Hand Surg. 2006;40:8–12. 14. Kroll SS. Fat necrosis in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg. 2000;106:576–583. 15. Blondeel N, Vanderstraeten GG, Monstrey SJ, et al. The donor site morbidity of free DIEP flaps and free TRAM flaps for breast reconstruction. Br J Plast Surg. 1997;50:322–330. 16. Spear SL, Ducic I, Cuoco F, et al. Effect of obesity on flap and donor-site complications in pedicled TRAM flap breast reconstruction. Plast Reconstr Surg. 2007; 119:788–795. 17. Selber JC, Kurichi JE, Vega SJ, et al. Risk factors and complications in free TRAM flap breast reconstruction. Ann Plast Surg. 2006;56:492–497. 18. Rossetto LA, Abla LE, Vidal R, et al. Factors associated with hernia and bulge formation at the donor site of the pedicled TRAM flap. Eur J Plast Surg. 2010; 33:203–208. 19. Momeni A, Ahdoot MA, Kim RY, et al. Should we continue to consider obesity a relative contraindication for autologous microsurgical breast reconstruction? J Plast Reconstr Aesthet Surg. 2012;65:420–425. 20. Ochoa O, Chrysopoulo M, Nastala C, et al. Abdominal wall stability and flap complications after deep inferior epigastric perforator flap breast reconstruction: does body mass index make a difference? Analysis of 418 patients and 639 flaps. Plast Reconstr Surg. 2012;130:21e–33e. 21. Garvey PB, Buchel EW, Pockaj BA, et al. The deep inferior epigastric perforator flap for breast reconstruction in overweight and obese patients. Plast Reconstr Surg. 2005;115:447–457. 22. Hofer SO, Damen TH, Mureau MA, et al. A critical review of perioperative complications in 175 free deep inferior epigastric perforator flap breast reconstructions. Ann Plast Surg. 2007;59:137–142. 23. Fischer JP, Nelson JA, Sieber B, et al. Free tissue transfer in the obese patient: an outcome and cost analysis in 1258 consecutive abdominally based reconstructions. Plast Reconstr Surg. 2013;131:681e–692e. 24. Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA. 2000;283:2008–2012. 25. Wan DC, Tseng CY, Anderson-Dam J, et al. Inclusion of mesh in donor-site repair of free TRAM and muscle-sparing free TRAM flaps yields rates of abdominal complications comparable to those of DIEP flap reconstruction. Plast Reconstr Surg. 2010;126:367–374. 26. Seidenstuecker K, Munder B, Mahajan AL, et al. Morbidity of microsurgical breast reconstruction in patients with comorbid conditions. Plast Reconstr Surg. 2011;127:1086–1092. 27. Schrey A, Kinnunen I, Kalliokoski K, et al. Perfusion in free breast reconstruction flap zones assessed with positron emission tomography. Microsurgery. 2010;30:430–436. 28. Guerra AB, Metzinger SE, Bidros RS, et al. Bilateral breast reconstruction with the deep inferior epigastric perforator (DIEP) flap. Ann Plast Surg. 2004; 52:246–252. 29. Bailey SH, Saint-Cyr M, Wong C, et al. The single dominant medial row perforator DIEP flap in breast reconstruction: three-dimensional perforasome and clinical results. Plast Reconstr Surg. 2010;126:739–751. 30. Holm C, Mayr M, Höfter E, et al. Perfusion zones of the DIEP flap revisited: a clinical study. Plast Reconstr Surg. 2006;117:37–43. 31. Cheng MH, Robles JA, Ulusal BG, et al. Reliability of zone IV in the deep inferior epigastric perforator flap: a single center's experience with 74 cases. Breast. 2006; 15:158–166. 32. Kim H, Lim SY, Pyon JK, et al. Rib-sparing and internal mammary arterypreserving microsurgical breast reconstruction with the free DIEP flap. Plast Reconstr Surg. 2013;131:327e–334e. 33. Takeishi M, Fujimoto M, Ishida K, et al. Muscle sparing-2 transverse rectus abdominis musculocutaneous flap for breast reconstruction: a comparison with deep inferior epigastric perforator flap. Microsurgery. 2008;28:650–655.

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34. Elliott LF, Seify H, Bergey P. The 3-hour muscle-sparing free TRAM flap: safe and effective treatment review of 111 consecutive free TRAM flaps in a private practice setting. Plast Reconstr Surg. 2007;120:27–34. 35. Man LX, Selber JC, Serletti JM. Abdominal wall following free TRAM or DIEP flap reconstruction: a meta-analysis and critical review. Plast Reconstr Surg. 2009; 124:752–764. 36. Fischer JP, Nelson JA, Kovach SJ, et al. Impact of obesity on outcomes in breast reconstruction: analysis of 15,937 patients from the ACS-NSQIP datasets. J Am Coll Surg. 2013;217:656–664. 37. Reyna RE, Feldmann ME, Evans ZP, et al. Obesity alters rat abdominal flap survival. Am Surg. 2006;72:764–771; discussion 771–762. 38. Egeberg A, Rasmussen MK, Sorensen JA. Comparing the donor-site morbidity using DIEP, SIEA or MS-TRAM flaps for breast reconstructive surgery: a metaanalysis. J Plast Reconstr Aesthet Surg. 2012;65:1474–1480.

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39. Wu LC, Bajaj A, Chang DW, et al. Comparison of donor-site morbidity of SIEA, DIEP, and muscle-sparing TRAM flaps for breast reconstruction. Plast Reconstr Surg. 2008;122:702–709. 40. Selber JC, Samra F, Bristol M, et al. A head-to-head comparison between the muscle-sparing free TRAM and the SIEA flaps: is the rate of flap loss worth the gain in abdominal wall function? Plast Reconstr Surg. 2008;122:348–355. 41. Selber JC, Nelson J, Fosnot J, et al. A prospective study comparing the functional impact of SIEA, DIEP, and muscle-sparing free TRAM flaps on the abdominal wall: part I. Unilateral reconstruction. Plast Reconstr Surg. 2010;126: 1142–1153. 42. Selber JC, Fosnot J, Nelson J, et al. A prospective study comparing the functional impact of SIEA, DIEP, and muscle-sparing free TRAM flaps on the abdominal wall: part II. Bilateral reconstruction. Plast Reconstr Surg. 2010;126: 1438–1453.

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Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Effects of Obesity on Postoperative Complications After Breast Reconstruction Using Free Muscle-Sparing Transverse Rectus Abdominis Myocutaneous, Deep Inferior Epigastric Perforator, and Superficial Inferior Epigastric Artery Flap: A Systematic Review and Meta-analysis.

Although several studies have found obesity to increase the risk of postoperative morbidity in autologous breast reconstruction, there remains some co...
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