Autologous breast reconstruction has evolved BREAST

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1 BREAST 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 Oscar Ochoa, M.D. Minas Chrysopoulo, M.D. Chet Nastala, M.D. Peter Ledoux, M.D. Steven Pisano, M.D. San Antonio, Texas Background: Promoted by reports of decreased donor-site morbidity, deep inferior epigastric perforator (DIEP) flaps have gained significant popularity. Increasing body mass index is associated with poor outcomes in breast reconstruction using traditional techniques. The authors aimed to define complications with increasing body mass index among patients undergoing DIEP flap breast reconstruction. Methods: A retrospective analysis of 639 DIEP flaps in 418 patients was performed. Patients were stratified into five groups based on body mass index. Data regarding medical comorbidities, adjuvant therapies, timing of reconstruction, active tobacco use, and surgical history were collected. Primary outcomes were compared among groups. Results: The average body mass index for the entire population was 28.3 (range, 17 to 42). Increasing body mass index was associated with increased incidence of hypertension, previous abdominal operations, and length of follow-up. Flap complications stratified by group demonstrated significantly increased delayed wound healing complications in severely obese patients compared with lower body mass index groups. Donor-site complications stratified by body mass index demonstrated significantly increased delayed wound healing and overall complications among morbidly obese patients compared with other groups. Incidence of abdominal wall bulging and hernia formation was not significantly different among groups. Conclusions: Increasing body mass index predisposes patients to delayed wound healing complications in both flap and donor-site locations. Nevertheless, overall flap complications remain similar across all body mass index groups. Abdominal wall stability was maintained. Given a similar flap complication profile and maintenance of abdominal stability, DIEP flaps are recommended in patients with increased body mass index. (Plast. Reconstr. Surg. 130: 21e, 2012.) CLINICAL QUESTION/LEVEL OF EVDENCE: Risk, II. From the Plastic Reconstructive and Microsurgical Associates of South Texas, P.A. Received for publication July 28, 2011; accepted January 11, Copyright 2012 by the American Society of Plastic Surgeons DOI: /PRS.0b013e d09 Autologous breast reconstruction has evolved considerably throughout the years. Since the original description of pedicled transverse rectus abdominis musculocutaneous (TRAM) flaps, 1 abdomen-based breast reconstruction has been able to achieve reproducible and increasingly reliable aesthetic results. However, with sacrifice of the underlying rectus muscle and fascia, abdominal wall laxity and hernia formation were quickly identified as limitations of pedicled TRAM flaps. 2,3 Consequently, because of significant donor-site morbidity, pedicled TRAM flaps are considered relatively contraindicated in high-risk populations, such as patients with obesity. 4 6 Disclosure: The authors have no financial interest to declare in relation to the content of this article. 21e

2 Plastic and Reconstructive Surgery July 2012 In an attempt to decrease donor-site morbidity, free TRAM flaps were developed, 7 enabling limited fascial and rectus muscle resection. Previous studies 8 10 comparing pedicled versus free TRAM flaps have verified improved abdominal wall stability with limited muscle and fascial resection. Free TRAM flaps have nonetheless been unable to overcome the inherent predisposition for abdominal wall instability associated with obesity. 11 With elimination of fascial and rectus muscle harvest, deep inferior epigastric perforator (DIEP) flaps promise improved abdominal wall stability. Previous studies have documented improved abdominal wall stability among patients following DIEP flap breast reconstruction compared with free TRAM flaps. In contrast, because of the delicate dissection required for DIEP flap elevation, concerns have been raised regarding DIEP flap reliability. 9,13,17 Furthermore, previous studies 11,18 have identified obesity as an important factor decreasing flap reliability following free and pedicled TRAM flap surgery. Ultimately, the effects of obesity on flap and donor-site morbidity following DIEP flap breast reconstruction remain ill-defined. The purpose of the study is to determine the incidence of flap and donor-site morbidity following DIEP flap breast reconstruction as a function of body mass index. PATIENTS AND METHODS A retrospective chart review was conducted after institutional review board approval among consecutive patients who underwent DIEP flap breast reconstruction from January of 2006 to March of Patients were routinely offered DIEP flaps based on standard selection criteria used for free TRAM flaps regardless of body mass index. Six hundred thirty-nine DIEP flaps were performed on 418 patients by a single group practice (Plastic Reconstructive and Microsurgical Associates of South Texas). Data regarding patient demographics, medical comorbidities, active tobacco use, oncologic history, and adjuvant therapy were collected preoperatively. Active tobacco use was defined as use of tobacco products within 6 weeks of reconstruction. The number of previous abdominal operations, open and/or laparoscopic, was recorded. Preoperative body mass index was used to stratify patients into five groups: normal weight ( 24.9), overweight (25 to 29.9), obese (30 to 34.9), severely obese (35 to 39.9), and morbidly obese ( 40). DIEP flap reconstruction was performed by two board-certified plastic surgeons with extensive microsurgical experience working simultaneously. Breast mounds were reconstructed routinely with abdominal flap Hartrampf zones 1 and 3. Arterial and venous anastomoses were hand-sewn to internal mammary vessels using standard microsurgical technique. Intraoperative variables including number of perforators used, ischemia time, and overall reconstruction time were recorded. Fascial closure was performed primarily in two layers. Figure-of-eight interrupted sutures are placed followed by a simple running suture using 0 polypropylene for both layers. Mesh was not used prophylactically to reinforce the fascial closure regardless of preoperative body mass index. Length of hospital stay and time of follow-up (in days) were recorded. Primary outcomes were defined as postoperative donor-site morbidity and flap complications. For both flap and donor-site soft-tissue infections, further stratification into mild, moderate, and severe infections was performed to better define the degree of infectious complications. Mild infections were defined as clinically significant erythema, warmth, and induration requiring outpatient antibiotics. Moderate infections were defined as infections requiring débridement and wound packing in an ambulatory setting or use of parenteral antibiotics. Severe infections were defined as those requiring formal operative débridement. Similarly, for both flap and donor sites, delayed wound healing was further stratified into mild, moderate, and severe. Mild delayed wound healing was defined as minor wound dehiscence requiring local therapies, including wound packing. Moderate delayed wound healing was defined as wound dehiscence requiring vacuum-assisted closure therapy. Severe delayed wound healing complications were defined as extensive wound dehiscence requiring operative intervention. Recorded variables and incidence of primary outcomes were compared between body mass index groups and analyzed for statistical differences. Associations involving categorical variables were assessed using Pearson s chi-square test or Fisher s exact test, as appropriate. The Kruskal- Wallis test was used to assess associations involving continuously distributed variables. Patients having bilateral reconstruction could contribute to more than one complication outcome category if present. Therefore, associations involving flap complications were assessed using a logistic regression model with binary response that accounted for correlation introduced by bilateral reconstructions. Logistic regression with forward selection 22e

3 Volume 130, Number 1 DIEP Flap Complications was used to assess associations between potentially important covariates and the most prevalent complication outcomes observed. All statistical comparisons were performed using a significance level of 5 percent and SAS 9.2 (SAS Institute, Inc., Cary, N.C.). RESULTS The mean age of the patients in the study population was 50.4 years (range, 27 to 74 years). Mean body mass index was 28.3 (range, 17 to 42). Hypertension (25.8 percent) and cardiac disease (6.6 percent) were the most common medical comorbidities overall. With the exception of migraine headaches (17.7 percent), the incidence of other reported medical comorbidities was approximately 5 percent or less. Recent use of tobacco products was present in 8.1 percent (Table 1). A history of at least one previous abdominal operation (laparoscopic or open) was present in 68.4 percent, with a mean prevalence overall of 1.3 operations per patient. Unilateral or bilateral reconstructions were performed in nearly equal numbers 197 (47.1 percent) versus 221 (52.9 percent), respectively with most (77.1 percent) performed in the immediate setting. Neoadjuvant irradiation and chemotherapy were administered in 28.4 percent and 41.6 percent of patients, respectively, with only 5.1 percent of patients requiring radiotherapy postoperatively. One-third of patients received postoperative chemotherapy, and recurrence of breast cancer was identified in five patients (1.2 percent) (Table 2). The mean time required for unilateral reconstructions was minutes (4.2 hours), whereas bilateral reconstructions required minutes (6.9 hours). Mean flap ischemia time for reconstructed right and left breasts was 23.6 and 22.7 minutes, respectively. The mean number of perforators used for right and left breast flaps were 2 and 1.9, respectively (Table 3). Table 1. Prevalence of Medical Comorbidities in the Study Population Variable No. (%) Hypertension 108 (25.8) Diabetes mellitus 21 (5) Cardiac disease 28 (6.7) Pulmonary disease 19 (4.5) Peripheral vascular disease 1 (0.2) Autoimmune disease 23 (5.5) Migraine 74 (17.7) Coagulopathy 11 (2.6) Tobacco 34 (8.1) Table 2. Laterality, Timing, Adjuvant Therapy, and Recurrence in the Study Population Variable No. (%) Unilateral 197 (47.1) Bilateral 221 (52.9) Immediate 77.5% Delayed 22.5% Radiotherapy Preoperatively 118 (28.4) Postoperatively 21 (5.1) Chemotherapy Preoperatively 172 (41.6) Postoperatively 141 (34.1) Cancer recurrence 5 (1.2) Table 3. Reconstruction Time, Ischemia Time, and Number of Perforators in the Study Population Variable Mean Reconstruction, min Unilateral Bilateral Flap ischemia, min Right 23.6 Left 22.7 No. of perforators Right 2 Left 1.9 Overall, DIEP flap soft-tissue infections were seen in 33 cases (5.4 percent), with 16 (2.6 percent) classified as mild and 15 (2.5 percent) classified as moderate. Severe soft-tissue infections were seen in only two cases (0.3 percent). Delayed flap wound healing was seen in 38 cases (6.2 percent), with 36 (5.9 percent) classified as mild. Fat necrosis was clinically evident in 63 cases (10.4 percent), whereas seromas were seen in only five cases (0.8 percent). Acute and subacute hematomas were seen in 12 (1.9 percent) and 13 cases (2.1 percent), respectively. Acute vessel thrombosis was recognized and perfusion reestablished in four cases (0.6 percent), with complete flap failure in six cases (1.0 percent). Overall, 152 flap complications (23.8 percent) were reported (Table 4). Donor-site soft-tissue infections were documented in 30 patients (7.2 percent) overall, with 19 (4.5 percent) of these classified as mild and nine (2.2 percent) classified as moderate. Delayed donor-site wound healing was seen in 70 patients (16.7 percent), with 59 (14.1 percent) classified as mild. Seroma formation was reported in 27 cases (6.5 percent). No hematomas, acute or subacute, were encountered at donor sites postoperatively. During an average follow-up period of 1088 days (range, 720 to 1528 days), abdominal bulging was seen in one patient (0.2 percent), and six patients 23e

4 Plastic and Reconstructive Surgery July 2012 Table 4. Overall Incidence of Flap Complications Variable No. (%) Flap infection Total 33 (5.4) Mild 16 (2.6) Moderate 15 (2.5) Severe 2 (0.3) Delayed wound healing Total 38 (6.2) Mild 36 (5.9) Moderate 1 (0.2) Severe 1 (0.2) Perfusion complications Thrombosis 4 (0.6) Failure 6 (1.0) Acute hematoma 12 (1.9) Fat necrosis 63 (10.4) Subacute hematoma 13 (2.1) Seroma 5 (0.8) Total 152 (23.8) (1.4 percent) developed abdominal wall hernias. Overall, 108 donor-site complications (25.8 percent) were reported (Table 5). Stratified by body mass index, five groups of patients were identified (Table 6). When compared across all body mass index groups, the prevalence of hypertension was significantly (p 0.001) different between body mass index groups. Groups with a higher body mass index had a significantly higher prevalence of hypertension than lower body mass index groups (Fig. 1). Although a trend was observed with a higher prevalence of diabetes in higher body mass index groups, no significant differences were observed between body mass index groups regarding other recorded medical comorbidities or recent tobacco use (Table 7). The number of total previous abdominal operations was significantly (p 0.03) lower in normal weight patients compared with other body Table 5. Overall Incidence of Donor-Site Complications Variable No. (%) Donor-site infection Total 30 (7.2) Mild 19 (4.5) Moderate 9 (2.2) Severe 2 (0.5) Delayed wound healing Total 70 (16.7) Mild 59 (14.1) Moderate 8 (1.9) Severe 3 (0.7) Acute hematoma 0 (0) Seroma 27 (6.5) Subacute hematoma 0 (0) Abdominal bulge 1 (0.2) Hernia 6 (1.4) Total 108 (25.8) Table 6. Study Population Stratified by Body Mass Index Variable BMI No. (%) Normal (23.9) Overweight (36.6) Obese (27) Severely obese (10.8) Morbidly obese 40 7 (1.7) BMI, body mass index. mass index groups. Morbidly obese patients reported significantly (p 0.04) more previous open abdominal operations compared with normal and overweight patients (Fig. 2). Length of follow-up was significantly (p 0.03) different between body mass index groups, with normal weight (1137 days) and morbidly obese (1250 days) patients having the longest mean follow-up period (Fig. 3). No significant differences were observed between body mass index groups regarding age, laterality or timing of reconstruction, history of adjuvant therapy, or cancer recurrence (Tables 8 and 9). Mean operative times were significantly (p 0.03) different between body mass index groups undergoing unilateral reconstructions, with the severely obese group (286 minutes) requiring significantly (p 0.05) longer operative times compared with normal weight (240 minutes) and obese (252 minutes) groups (Fig. 4). Mean operative times were similar among all body mass index groups undergoing bilateral reconstructions. Mean ischemia times for left breast reconstructions were similar between all body mass index groups. Mean ischemia time for right breast reconstructions were significantly (p 0.02) increased among severely obese patients (27.1 minutes) compared with lower body mass index groups (Fig. 5). The number of perforators used during flap elevation was similar between all body mass index groups for both right and left reconstructions (Table 10). Flap complication analysis demonstrated significantly (p 0.002) different rates of delayed wound healing between body mass index groups. Severely obese patients had a significantly (p 0.05) higher rate (20.6 percent) of delayed wound healing compared with lower body mass index groups (Fig. 6). The incidence of overall and other individual flap complications, including flap failure, were not significantly different between groups despite increasing body mass index (Table 11). Donor-site complication analysis demonstrated significantly different rates of delayed wound heal- 24e

5 Volume 130, Number 1 DIEP Flap Complications Fig. 1. Prevalence of hypertension by body mass index (BMI) group. Table 7. Prevalence of Medical Comorbidities and Tobacco Use by Body Mass Index Group Variable Normal (%) Overweight (%) Obese (%) Severely Obese (%) Morbidly Obese (%) Comorbidities Hypertension Diabetes mellitus Cardiac disease Pulmonary disease Peripheral vascular disease Arterial insufficiency Migraine Coagulopathy Tobacco p ing (p 0.05) and overall complications (p 0.02) between body mass index groups. The incidences of donor-site infection, acute or subacute hematomas, seroma formation, abdominal wall bulging, and hernia formation were not significantly different between groups despite increasing body mass index (Table 12). Donor-site delayed wound healing (p 0.03) and overall donor-site complications (p 0.01) were significantly increased in morbidly obese patients compared with lower body mass index groups (Fig. 7). When severity of delayed wound healing was compared across body mass index groups, morbidly obese patients experienced significantly (p 0.049) increased moderate wound healing complications (14.3 percent) compared with lower body mass index groups. In a multivariate logistic regression model, the incidence of complications at the donor-site and/or flap locations were examined against possible independent risk factors. Increased body mass index and active tobacco use were significantly (p 0.006) associated with delayed wound healing complications in both flap and donorsite locations. Increased body mass index and shorter reconstructive times were noted to be significantly (p 0.002) associated with flap complications in general, or any flap complications (Table 13). DISCUSSION In the largest reported series since that by Gill et al., 19 the current study analyzes flap and donorsite morbidity following 639 DIEP flaps on 418 patients. The study population characteristics closely reflect a growing trend of obesity in Western society 20 and daily clinical practice. In particular, approximately 40 percent of study patients had a body mass index of 30 or greater. The applicability of the current study findings are further underscored by the high incidence (68 percent) of previous abdominal surgery reported by patients. After stratification by body mass index groups, considerable homogeneity was observed in the study population regarding age, medical comorbidities, recent tobacco use, and adjuvant therapy, underscoring the independent effects of body mass index on flap and donor-site morbidity. 25e

6 Plastic and Reconstructive Surgery July 2012 Fig. 2. Mean abdominal operations by body mass index. Patients in the normal body mass index group reported significantly (p 0.03) lower number of operations overall compared with all other body mass index groups. Morbidly obese patients, on average, reported a significantly (p 0.04) higher number of open abdominal operations compared with normal and overweight body mass index groups. BMI, body mass index; Abd, abdomen. Fig. 3. Length of follow-up (in days) by body mass index (BMI). Normal (p 0.03) and morbidly obese (p 0.05) body mass index groups had significantly longer follow-up than overweight and severely obese groups. Table 8. Mean Age, Previous Abdominal Surgery, and Follow-Up by Body Mass Index Group Variable Normal Overweight Obese Severely Obese Morbidly Obese p Age, yr Abdominal surgery, no Laparoscopic Open Follow-up, days Flap Complications The current data support the safety of DIEP flaps in breast reconstruction, even in obese populations (Fig. 8). Overall flap complications rates (23.8 percent) coincide with previous studies of free TRAM flap 11 or DIEP flap based 19,21,22 reconstruction in more slender populations. Moreover, greater than 75 percent of procedures were per- 26e

7 Volume 130, Number 1 DIEP Flap Complications Table 9. Reconstruction Timing, Laterality, Adjuvant Therapy, and Cancer Recurrence by Body Mass Index Normal (%) Overweight (%) Obese (%) Severely Obese (%) Morbidly Obese (%) p Reconstruction 0.68 Immediate 110 (78) 184 (77) 146 (80.7) 48 (70.6) 7 (70) Delayed 31 (22) 55 (23) 35 (19.3) 20 (29.4) 3 (30) Laterality 0.06 Unilateral 59 (59) 67 (43.8) 45 (39.8) 22 (48.9) 4 (57.1) Bilateral 41 (41) 86 (56.2) 68 (60.2) 23 (51.1) 3 (42.9) XRT Preoperatively 29 (29.3) 42 (27.6) 32 (28.6) 13 (28.9) 2 (28.6) 1 Postoperatively 5 (5.1) 9 (5.9) 4 (3.6) 2 (4.4) 1 (14.3) 0.59 Chemotherapy Preoperatively 44 (44.9) 65 (43) 47 (42) 14 (31.1) 2 (28.6) 0.56 Postoperatively 32 (32.7) 55 (36.4) 40 (35.7) 10 (22.2) 4 (57.1) 0.27 Cancer recurrence 3 (3) 1 (0.7) 1 (0.9) 0 (0) 0 (0) 0.46 XRT, external radiation therapy. Fig. 4. Time (in minutes) required for unilateral DIEP breast reconstructions by body mass index (BMI). Severely obese patients required significantly (p 0.05) longer time for completion of reconstruction compared with all other body mass index groups. Fig. 5. Flap ischemia time (in minutes) for right breast reconstructions. Severely obese patients experienced significantly (p 0.02) longer flap ischemia time compared with other body mass index (BMI) groups. formed in the immediate setting, which has previously been associated with a higher rate of complications. 23 After stratification by body mass index, overall flap complications were highest (35.3 percent) in severely obese patients but were not statistically different compared with all other body mass index groups. Previous studies analyzing the effect of obesity on TRAM flap morbidity 27e

8 Plastic and Reconstructive Surgery July 2012 Table 10. Mean Reconstruction Time, Ischemia Time, Perforator Number by Body Mass Index Variable Normal Overweight Obese Severely Obese Morbidly Obese p Reconstruction, min Unilateral Bilateral Flap ischemia, min Right Left No. of perforators Right Left Fig. 6. Incidence of flap delayed wound healing. Severely obese patients had asignificantly(p 0.05)greaterincidenceofdelayedwoundhealingcompared with lower body mass index (BMI) groups. Table 11. Incidence of Flap Complications by Body Mass Index Normal Overweight Obese Severely Obese Morbidly Obese p No. of patients Flap infection Overall 4 (2.9) 12 (5.3) 13 (7.6) 4 (5.9) 0 (0) 0.41 Mild 3 (2.2) 6 (2.7) 6 (3.5) 1 (1.5) 0 (0) 0.74 Moderate 1 (0.7) 5 (2.2) 6 (3.5) 3 (4.4) 0 (0) 0.17 Severe 0 (0) 1 (0.4) 1 (0.6) 0 (0) 0 (0) NA Flap DWH Overall 2 (1.4) 9 (4) 12 (7.1) 14 (20.6) 1 (10) Mild 2 (1.4) 8 (3.6) 12 (7.1) 13 (19.1) 1 (10) Moderate 0 (0) 1 (0.4) 0 (0) 0 (0) 0 (0) NA Severe 0 (0) 0 (0) 0 (0) 1 (1.5) 0 (0) NA Perfusion complications 0.85 Thrombosis 2 (1.4) 1 (0.4) 1 (0.6) 0 (0) 0 (0) Failure 0 (0) 3 (1.3) 3 (1.7) 0 (0) 0 (0) Acute hematoma 5 (3.6) 3 (1.3) 4 (2.3) 0 (0) 0 (0) 0.39 Fat necrosis 17 (12.4) 22 (9.9) 17 (10) 7 (10.3) 0 (0) 0.95 Subacute hematoma 5 (3.6) 6 (2.7) 2 (1.2) 0 (0) 0 (0) 0.42 Seroma 1 (0.7) 2 (0.9) 1 (0.6) 1 (1.5) 0 (0) 0.42 Total 33 (23.4) 49 (20.5) 45 (24.9) 24 (35.3) 1 (10) 0.23 N/A, not applicable; DWH, delayed wound healing. reported flap complication rates between 39 and 56 percent 11,18 in obese populations. Most recently, a 14.6 percent flap complication rate has been reported 24 among patients with a body mass index greater than or equal to 30 after TRAM and DIEP flap reconstruction. The flap soft-tissue infection rate was 5.4 percent overall, coinciding with historical rates be- 28e

9 Volume 130, Number 1 DIEP Flap Complications Table 12. Incidence of Donor-Site Complications by Body Mass Index Normal (%) Overweight (%) Obese (%) Severely Obese (%) Morbidly Obese (%) p Donor-site infection Overall 7 (7) 8 (6.5) 8 (7.1) 2 (4.4) 3 (42.9) 0.08 Mild 3 (3) 6 (3.9) 6 (5.3) 2 (4.4) 2 (28.6) Moderate 4 (4) 2 (1.3) 2 (1.8) 0 (0) 1 (14.3) Severe 0 (0) 2 (1.3) 0 (0) 0 (0) 0 (0) Delayed wound healing Overall 14 (14) 25 (16.3) 20 (17.7) 7 (15.6) 4 (57.1) 0.03 Mild 12 (12) 20 (13.1) 17 (15) 7 (15.6) 3 (42.9) Moderate 2 (2) 5 (3.3) 0 (0) 0 (0) 1 (14.3) Severe 0 (0) 0 (0) 3 (2.7) 0 (0) 0 (0) Acute hematoma 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 Seroma 4 (4) 10 (6.5) 11 (9.7) 2 (4.4) 0 (0) 0.53 Subacute hematoma 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 Abdominal bulge 1 (1) 0 (0) 0 (0) 0 (0) 0 (0) 0.36 Hernia 1 (1) 2 (1.3) 3 (2.7) 0 (0) 0 (0) Total 25 (25) 45 (29.4) 38 (33.6) 11 (24.4) 6 (85.7) 0.02 Fig. 7. Incidence of donor-site complications by body mass index (BMI). Morbidly obese patients experienced significantly greater delayed wound healing (p 0.03) and overall (p 0.01) complications compared with lower body mass index groups. Table 13. Independent Risk Factors for Complications Complication OR 95% CI p Any flap complication BMI Reconstruction time Any delayed wound healing complication BMI Tobacco use OR, odds ratio; CI, confidence interval; BMI, body mass index. tween 2.4 and 12.5 percent. 25,26 Half of the reported infections were treated effectively with oral antibiotics, and only two required operative intervention. Unlike what has been reported for pedicled TRAM flaps, 18 the incidence of flap infection was not increased with increasing body mass index in the current study, resembling prior findings following free TRAM flap surgery. 11 As in previous studies, 19,22,23,25 acute and subacute hematomas were uncommon (1.9 and 2.1 percent, respectively) and were unaffected by body mass index. Delayed wound healing in the current study was attributable primarily to mastectomy skin flap necrosis, with no reported cases of partial DIEP flap loss. Thirty-eight flaps (6.2 percent) were affected by delayed wound healing at the interface with the recipient site, with 36 (5.9 percent) requiring minor débridement of native breast skin. As in previous reports following pedicled, 18 free TRAM flaps 11 and, more recently, DIEP flaps, 24 obesity was a significant factor associated with delayed wound healing at the recipient site. More 29e

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11 Volume 130, Number 1 DIEP Flap Complications precisely, in this study, increased body mass index was associated with a higher incidence of mastectomy flap compromise. Severely obese patients experienced nearly three times the rate of delayed wound healing compared with other body mass index groups. Nonetheless, the severity of wound healing complications was not increased with increasing body mass index such that moderate and severe wound healing complications were similar across all groups. Fat necrosis and perfusion complications such as vessel thrombosis and total flap loss are strong indicators of flap reliability. Reported rates of fat necrosis following DIEP flap reconstruction are varied in the literature, ranging from 1.8 to 29 percent. 9,13,17,19,21,22,25 28 In the current study overall, clinical fat necrosis was evident in 10.4 percent of DIEP flaps. Stratified by body mass index, rates of fat necrosis were unaffected by body habitus, as reported previously for pedicled 18 and free TRAM flaps. 11 As in most successful series, 17,19,22 vessel thrombosis and flap loss remained an infrequent complication, with rates of 0.6 percent and 1.0 percent, respectively. Although recent reports 24 have suggested increased flap loss in higher body mass index patients, the current study did not support these findings. Despite statistically similar overall complication rates across all body mass index groups, logistic regression analysis identified body mass index as an independent risk factor for any flap complication. Interestingly, shorter operative time was also identified as an independent risk factor for any flap complication. On close analysis, this counterintuitive finding is likely explained by the clinical observation of larger diameter perforators generally found in obese patients making dissection and flap harvest less time-consuming. Indeed, relatively shorter operative times were seen in severely obese patients undergoing bilateral breast reconstruction. Donor-Site Complications Because of the quantitative and qualitative heterogeneity of recorded variables in published series, overall donor-site complication rates are dif- Fig. 8. (Above, left) Preoperative anteroposterior view. (Center, left) Preoperative right oblique view. (Below, left) Preoperative right lateral view. (Above, right) Postoperative anteroposterior view. (Center, right) Postoperative right oblique view. (Below, right) Postoperative right lateral view. ficult to interpret and compare. In the current study, the overall incidence of donor-site complications was 25.8 percent. Increasing body mass index was associated with increased overall donorsite complications coinciding with similar trends observed previously among obese patients following TRAM 11,18,29 or DIEP flap 30 reconstruction. On close examination, however, differences in overall donor-site complications based on body mass index in the current series can be attributed to delayed wound healing, as other individual complications were similar across all body mass index groups. Coinciding with previous series, 21,24,26,27 the current study reports a 6.5 percent incidence of seroma formation. Moreover, formation of donorsite seromas were not increased despite increasing body mass index, in contrast to previous studies following either DIEP 24,26 or TRAM flap based 11,18 reconstruction. Although statistical significance was not reached, a trend toward increased donor-site infection overall was observed with increasing body mass index. Similar trends were reported previously, 11,18,30 underscoring the inherent infectious risk associated with obesity. Analysis of the severity of infectious donorsite complications identifies most as mild, responsive to outpatient antibiotics, and similar across all body mass index groups. In the current study, the incidence of overall donor-site delayed wound healing was increased with increasing body mass index. In fact, along with active tobacco use, increased body mass index was identified as an independent risk factor for delayed wound healing in both flap and donor-site locations. Although primarily attributed to morbidly obese patients, statistical significance was reached between body mass index groups for overall and moderate donor-site delayed wound healing complications. Severe complications, however, were seldom observed and were independent of body mass index. Of note, morbidly obese patients reported an increased number of previous open abdominal operations, which has been associated with significantly increased delayed wound healing following DIEP flap surgery. 27 Supported by the current findings and significant personal experience, we suggest that additional emphasis be placed on the risk of abdominal wound healing complications when counseling patients with a high body mass index preoperatively. In the current study, despite a high-risk population, the incidences of abdominal bulging and hernia formation were minimal (0.2 percent and 31e

12 Plastic and Reconstructive Surgery July percent, respectively) during a lengthy follow-up period (mean, 1088 days; range, 720 to 1528 days). With preservation of supporting structures, abdominal integrity was effectively maintained despite increasing body mass index, evidenced by similar rates of abdominal bulging and hernia formation between all body mass index groups. Despite the relative success of DIEP flap breast reconstruction in obese patients reported in this study, surgeons should be cognizant of the increased risk associated with abdomen-based perforator flap surgery on obese patients. Further emphasis should be placed on specific means of risk-factor reduction along the reconstructive process. Preoperatively, maximal weight loss should be encouraged before immediate reconstruction without delaying oncologic treatments. In delayed reconstruction cases, reconstruction should be postponed until nutrition and weight loss are optimized and consistent abstinence from tobacco use is achieved. Intraoperatively, abdominal flap undermining should be minimized, with preservation of adipocutaneous perforators to the upper abdominal apron. Furthermore, if undermining of the upper abdomen is required for donor-site closure, this should be performed in discontinuous fashion to maximize blood flow to the upper abdominal apron. In addition, mastectomy skin flap viability should be evaluated critically before flap deepithelialization. Postoperatively, optimization of nutrition is continued in an attempt to encourage wound healing and expedite overall recovery. CONCLUSIONS Deep inferior epigastric perforator flaps represent a significant advance in the evolution of abdomen-based breast reconstruction. Potential abdominal donor-site morbidity and flap reliability play a significant role in determining reconstructive options for high-risk patients such as those with previous abdominal surgery or obesity. The current findings demonstrate excellent reliability of DIEP flaps in obese patients. In addition, by eliminating sacrifice of rectus musculature and maintaining the integrity of the overlying fascia, DIEP flaps effectively maintain abdominal wall stability even in obese populations. Consequently, DIEP flaps are safe in obese populations and in fact may be the recommended method of abdomen-based breast reconstruction in patients with a body mass index less than 40. Oscar Ochoa, M.D Huebner Road San Antonio, Texas dr.ochoa@prmaplasticsurgery.com REFERENCES 1. Hartrampf CR, Scheflan M, Black PW. Breast reconstruction with a transverse abdominal island flap. Plast Reconstr Surg. 1982;69: Watterson PA, Bostwick J III, Hester YR Jr, Bried JT, Taylor GI. TRAM flap anatomy correlated with a 10-year clinical experience with 556 patients. Plast Reconstr Surg. 1995;95: Paige KT, Bostwick J III, Bried JT, Jones G. A comparison of morbidity from bilateral, unipedicled and unilateral, unipedicled TRAM flap breast reconstructions. Plast Reconstr Surg. 1998;101: Scheflan M, Kalisman M. Complications of breast reconstruction. Clin Plast Surg. 1984;11: Hartrampf CR Jr, Bennett GK. Autogenous tissue reconstruction in the mastectomy patient: A critical review of 300 patients. Ann Surg. 1987;205: Scheflan M, Dinner MI. The transverse abdominal island flap: Part I. Indications, contraindications, results, and complications. Ann Plast Surg. 1983;10: Holmström H. The free abdominoplasty flap and its use in breast reconstruction: An experimental study and clinical case report. Scand J Plast Reconstr Surg. 1979;13: Schusterman MA, Kroll SS, Weldon ME. Immediate breast reconstruction: Why the free TRAM over the conventional TRAM flap? Plast Reconstr Surg. 1992;90: ; discussion Nahabedian MY, Dooley W, Singh N, Manson PN. Contour abnormalities of the abdomen after breast reconstruction with abdominal flaps: The role of muscle preservation. Plast Reconstr Surg. 2002;109: Alderman AK, Wilkins EG, Kim HM, Lowery JC. Complications in postmastectomy breast reconstruction: Two-year results of the Michigan Breast Reconstruction Outcome Study. Plast Reconstr Surg. 2002;109: 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: 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: Kroll SS. Fat necrosis in free transverse rectus abdominis myocutaneous and deep epigastric perforator flaps. Plast Reconstr Surg. 2000;106: Bonde CT, Christensen DE, Elberg JJ. Ten years experience of free flaps for breast reconstruction in a Danish microsurgical center: An audit. Scand J Plast Reconstr Surg Hand Surg. 2006;40: Sheer AS, Novak CB, Neligan PC, Lipa JE. Complications associated with breast reconstruction using a perforator flap compared with a free TRAM flap. Ann Plast Surg. 2006;56: 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: Nahabedian MY, Tsangaris T, Momen B. Breast reconstruction with the DIEP flap or the muscle-sparing (MS-2) free TRAM flap: Is there a difference? Plast Reconstr Surg. 2005: 115; ; discussion e

13 Volume 130, Number 1 DIEP Flap Complications 18. Spear SL, Ducic I, Cuoco F, Taylor N. Effect of obesity on flap and donor-site complications in pedicled TRAM flap breast reconstruction. Plast Reconstr Surg. 2007;119: Gill PS, Hunt JP, Guerra AM, et al. A 10-year retrospective review of 758 DIEP flaps for breast reconstruction. Plast Reconstr Surg. 2004;113: Flegal KM, Carroll MD, Ogden CL, Curtin LR. Prevalence and trends in obesity among US adults, JAMA 2010;303: Drazan L, Vesely J, Hyza P, et al. Bilateral breast reconstruction with DIEP flaps: 4 years experience. J Plast Reconstr Aesthet Surg. 2008;61: Selber JC, Serletti JM. The deep inferior epigastric perforator flap: Myth and reality. Plast Reconstr Surg. 2010;125: Sullivan SR, Fletcher DR, Isom CD, Isik FF. True incidence of all complications following immediate and delayed breast reconstruction. Plast Reconstr Surg. 2008;122: Seidenstuecker K, Munder B, Mahajan AL, Richrath P, Behrendt P, Andree C. Morbidity of microsurgical breast reconstruction in patients with comorbid conditions. Plast Reconstr Surg. 2011;127: Chen CM, Halvorson EG, Disa JJ, et al. Immediate postoperative complications in DIEP versus free/muscle-sparing TRAM flaps. Plast Reconstr Surg. 2007;120: Garvey PB, Buchel EW, Pockaj BA, et al. DIEP and pedicled TRAM flaps: A comparison of outcomes. Plast Reconstr Surg. 2006;117: ; discussion Parrett BM, Caterson SA, Tobias AM, Lee BT. DIEP flaps in women with abdominal scars: Are complication rates affected? Plast Reconstr Surg. 2008;121: Keller A. The deep inferior epigastric perforator free flap for breast reconstruction. Ann Plast Surg. 2001;46: ; discussion Vyas RM, Dickinson BP, Fastekjian JH, Watson JP, Dalio AL, Crisera CA. Risk factors for abdominal donor-site morbidity in free flap breast reconstruction. Plast Reconstr Surg. 2008; 121: Garvey PB, Buchel EW, Pockaj BA, Gray RJ, Samson TD. The deep inferior epigastric perforator flap for breast reconstruction in overweight and obese patients. Plast Reconstr Surg. 2005;115: e