Received: 7 April 2020 | Accepted: 8 June 2020 DOI: 10.1002/jso.26073 RESEARCH ARTICLE The largest multicentre data collection on prepectoral breast reconstruction: The iBAG study Jaume Masià MD, PhD | iBAG Working Group Department of Plastic Surgery, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma Abstract de Barcelona, Barcelona, Spain Background and Objectives: In the last years, prepectoral breast reconstruction has Correspondence increased its popularity, becoming a standard reconstructive technique by preser- Jaume Masià, MD, PhD, Department of Plastic Surgery, Hospital de la Santa Creu i Sant Pau, ving pectoralis major anatomy and functionality. Nevertheless, the lack of solid and Universitat Autonoma de Barcelona, Sant extensive data negatively impacts on surgeons’ correct information about post- Antoni M.Claret 167, 08025 Barcelona, Spain. Email: jmasia@santpau.cat operative complication rates and proper patient selection. This study aims to collect the largest evidence on this procedure. Methods: A multicentre retrospective audit, promoted by the Barcelona Hospital, collected the experience of 30 centers on prepectoral breast reconstruction with Braxon ADM. The study had the scientific support of INPECS and IIB societies which provided the online database Clinapsis. Results: A total of 1450 procedures were retrospectively collected in a 6‐year period. Mean age 52.4 years, BMI 23.9, follow‐up 22.7 months. Reconstruction was carried out after a tumor in 77.1% of the cases, 20.1% had prophylactic surgery, 2.8% had revisions. Diabetes, smoke, and immunosuppression had an influence on complications occurrence, as well as implant weight. Capsular contracture was associated with postoperative radiotherapy, but the overall rate was low (2.1%). Complications led to implant loss in 6.5% of the cases. Conclusions: The international Braxon Audit Group multicentre data collection represents a milestone in the field of breast reconstruction, extensively improving the knowledge on this procedure. KEYWORDS acellular dermal matrix, braxon, breast reconstruction, prepectoral, radiotherapy Abbreviations: ACCIb, Ibero‐American Cochrane Collaboration Association; ADM, acellular dermal matrix; BMI, body mass index; DTI, direct‐to‐implant; GAM, generalized additive models; iBAG, International Braxon Audit Group; IIB, Institut d'investigaciò Biomèdica Sant Pau; INPECS, Instituto Para la Excelencia Clínica y Sanitaria; PPBR, prepectoral breast reconstruction; RR, relative risk; RT, radiation therapy or radiotherapy. All the participants to the iBAG study must be considered authors of the study. They all had substantial contributed to the design of work, drafted work, made the final approval, and agreed to be accountable for all aspects of the work. The full list of authors is reported at the end of the paper. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- - This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2020 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals LLC 848 | wileyonlinelibrary.com/journal/jso J Surg Oncol. 2020;122:848–860. MASIÀ ET AL. | 849 1 | INTRODUCTION 2 | M A T E R I A L S AN D M E T H O D S Breast cancer nowadays represents the most common tumor among 2.1 | Study design and participants women, with over 2 million new cases in 2018. Currently, its surgical treatment is based on oncoplastic surgery, a synthesis between those At the beginning of 2018 the coordinating center, Santa Creu i Sant Pau two disciplines with the final goal of an outcome balanced between the Hospital of Barcelona (Spain), promoted an international audit on PPBR best oncologic and cosmetic results. Indeed, since its conception, breast to collect and analyze homogeneous data with the aim of creating the reconstruction helped patients look “normal” when dressed; more re- largest evidence on this procedure. This study had the scientific support cently, advancements in surgical techniques and medical technologies of Institut d'investigaciò Biomèdica Sant Pau (IIB) and Instituto Para la have raised the bar so that patients can feel esthetically pleasing also Excelencia Clínica y Sanitaria (INPECS), created by the Ibero‐American 1 unclothed. During the past decades, the surgical approach to breast Cochrane Collaboration Association (ACCIb) which provided the online cancer has evolved from radical mastectomy to the development of database CLINAPSIS. The access to the database was protected by breast‐conserving surgery and reconstructive techniques. In fact, after single‐user login credentials; it collected all information recorded in an a nipple or skin‐sparing mastectomy, the opportunity of having per- anonymized format. Data were managed by the above‐mentioned in- formed an immediate reconstruction represents a great advantage for dependent organisms (IIB and INPECS) to avoid any bias. patients, owing to its significant psychosocial benefits. Currently, im- The coordinating center of Barcelona invited to take part in the mediate implant‐based breast reconstruction (IBR) represents 81.9% of study of all EU and UK plastic and breast units performing PPBRs all breast reconstructive procedures.2 routinely and having performed more than 10 procedures with the However, only in the last decade, surgeons approached the Braxon ADM (DECOmed Srl). This collagen membrane is the most used prepectoral technique considering the importance of the role of the for PPBR and the sole with a specific patented design that allows a pectoralis major muscle and the possibility to avoid its recruitment standardized wrapping technique. The various options in ADM assembly for implant coverage: starting with the first cases described by Berna constitute a critical point in the analysis of the outcomes of the proce- et al, the subcutaneous breast implant positioning becomes a con- dure since the wrapping phase of the reconstructive technique is op- crete option, along with a complete breast implant wrapping with a erator sensitive. The use of different devices to cover the breast implant large sheet of ADM to prevent the direct contact of the silicone could lead to inhomogeneous data collection due to the different ma- prosthesis with the surrounding tissues.3,4 terials and the nonstandardized implant covering procedure. Prepectoral breast reconstruction (PPBR) has quickly become With the aim of obtaining uniform data, all the consecutive more and more popular due to its satisfying esthetic outcomes, low PPBRs carried out only with Braxon porcine ADM from November functional detriment, and low complication rate. In fact, whereas the 2012 to June 2018 were retrospectively analyzed. Patients’ inclusion traditional submuscular reconstructive technique involves several criteria to PPBR were defined according to each center practice; drawbacks, such as unpleasant esthetic results and postoperative indeed, some general guidelines were already published about pa- discomfort due to implant displacement, animation deformity, and tient's selection for PPBR procedure and they include women with no capsular contracture, PPBR has overcome most of them.5,6 history of radiation, non‐ or ex‐smokers, a good subcutaneous layer, a Unfortunately, despite the current multiplicity of different devices well‐perfused skin flap, an estimated mastectomy weight of less than committed to PPBR, there is still a lack of high‐quality evidence to 500 g and tumors not invading skin or chest wall, or those with in- support the safety of these new materials. In fact, most of the published flammatory nature. Considering the retrospective nature of this studies are limited to small single‐center experiences with no homo- study, the authors do not set any exclusion criteria with the aim to geneous outcomes.7‐9 As mentioned above, the first biologic membrane verify any association between patient characteristics and post- able to completely cover a silicone implant to position it sub- operative complications. Thus, if some of the 30 centers involved in cutaneously was a 0.6 mm‐thick preshaped porcine ADM (Braxon; the iBAG study enlarged the indication, therefore offering PPBR to 3 DECOmed Srl, Venice, Italy). To date, this device represents the most thin or obese women, as well as diabetics or smokers, data coming widely used one for PPBR in European and UK breast centers and the from these cases were analyzed as well. The sole patients excluded only ADM with a specific patented design that allows a standardized from the analysis were those with less than 3 months of follow‐up. wrapping technique, reducing the number of variables so that data can Data analyzed were patients’ age, body mass index (BMI), co- 10 be more easily compared among different centers. After a pre- morbidities, smoking status, tumor classification, neo‐adjuvant or liminary multicentre study on 100 PPBR cases carried out with Braxon adjuvant chemotherapy, previous or adjuvant radiation therapy (RT), ADM,11 the first author encouraged a larger EU‐UK database on PPBR previous breast surgery, uni‐ or bilateral procedures, type of surgery performed with the same device to obtain valuable evidence about (therapeutic, prophylactic or revision), type of mastectomy, breast outcomes and risk factors potentially linked to postoperative compli- skin incision, type of implant used, implant volume, axillary surgery, cations: for this reason, the group of study was defined as international postoperative therapies, and complications. Complications were Braxon Audit Group (iBAG). Our study wants to represent an extensive classified in “immediate” or “late” whether if they occurred respec- and homogeneous retrospective multicentre data collection that sets tively within or after 3 months from surgery. The complications ob- the basis for future randomized prospective studies. served included seroma, wound dehiscence, hematoma, skin necrosis, 850 | MASIÀ ET AL. infection, implant extrusion, implant rotation, capsular contracture, for patients requiring revision surgery due to implant‐related rippling, and implant loss. Moreover, we collected all details about complications or undesired surgical outcomes. pre‐ and postoperative medical treatments, hospitalization period, In all cases, perioperative and postoperative antibiotics and and pre‐ and postoperative patients’ pictures. drains were used according to local policy. 2.2 | Ethical standards 2.4 | Statistical analysis The research protocol of the study was approved by the Ethics Com- Considering the relevant sample size, χ² and the Student t test tests mittee of the Santa Creu i Sant Pau Hospital; each participating center were firstly used to study all independent variables potentially influ- was required to obtain local committee approval. In accordance with encing the studied outcome, particularly postoperative complications. A the Declaration of Helsinki of 1975, as revised in 1983, all patients model was then designed for all variables to explain the evidence de- were asked to provide written consent for the use of their personal rived from the data set; it was based on hierarchical and generalized data, as part of the standard surgical consent of their institutions. Pa- additive models (GAM), mainly dictated by the poor plausibility of a tients’ data were visible only to the supervisors of each center where linear link between regressors and the response variable, which need the reconstructive procedure was carried out; no one else had access to exploit the flexibility of the GAM models. Moreover, for each vari- to those records. At the end of the period of data collection, the co- able there were differences between several sample units dictated by ordinating center had the authorization to manage all the anonymized some specific characteristics of the data collection, thus motivating the data and to analyze them through statistical protocols. use of hierarchical models. Variables with more than 20% of missing data were excluded from the statistical analysis. The adopted approach studies simple models first, with a single 2.3 | Material and surgical procedure explanatory variable. After verifying the ability of these variables into the model description, they are included in a multiple logistic re- After mastectomy or surgery performed for revision purposes, the gression model, thus increasing the improvement of the estimates reconstructive phase involves the preparation of the ADM, which re- and the goodness of adaptation of the model to the data (Stepwise quires rehydration of 5 minutes in room‐temperature saline solution to Method). The level for statistical significance was set at P < .05. All facilitate its handling. Then, the ADM is wrapped around the breast statistical analyses were performed with R version 3.5.1 (2018), implant, its excess is cut away and it is closed by mean of absorbable 3/ Rstudio Version 1.1.456, CRAN project. 0 suture (Figure 1). Then, the completely wrapped implant is placed inside the breast pocket and fixed with cardinal stitches to the pec- toralis major muscle fascia and to the subcutaneous layer through 3 | RE SU LTS quilting sutures in the anterior part of the Braxon ADM, thus elim- inating dead spaces and supporting ADM integration. Thirty clinical centers, shared between Spain, UK, and Italy, took part in Surgeons involved in the study performed mastectomies according the study. Data collection started in September 2018 and finished in to specific clinical scenarios and their routine practice with the only January 2019; preliminary data of the present study were presented at common characteristic that the reconstructive phase did not entail the Barcelona Breast Meeting (BBM) and at Oncoplastic and Reconstructive pectoralis major; implant selection (round or anatomical shape, fixed‐ Breast Surgery (ORBS) conference, both held in 2019. volume or adjustable implant, as well as temporary tissue expander) The iBAG identified 1450 PPBR, carried out in 1186 women, in a depended on surgeons’ preference. Breast reconstruction was then 6‐year period comprised between November 2012 and June 2018. classified as two‐stage when performed with an expander or one‐stage Demographic, clinical, and surgical details of the patients are when a definitive implant was used. In some cases, the ADM was used explained in Table 1. F I G U R E 1 Standardized wrapping technique of Braxon ADM around the breast implant. The patented shaped allows a complete cover acting as an internal “implant bag” which distributes the weight of the silicone prosthesis around all the breast pocket and hides it from the direct contact with the organism. ADM acellular dermis matrix [Color figure can be viewed at wileyonlinelibrary.com] MASIÀ ET AL. | 851 T A B L E 1 Demographic, clinical and surgical details of the iBAG TABLE 1 (Continued) data collection No. (range/ No. (range/ Details percentage) Details percentage) Mastectomy weight 369.7 ± 201.4 No. patients 1186 (42‐1200) No. breasts 1450 Breast implant size (g) 349.2 ± 112.6 (100‐685) Follow‐up 22.7 ± 13.1 (3‐75.7) Breast implant Round 125 (8.6) Demographic/clinical profilec Anatomical 1298 (89.5) AGE 52.4 ± 11.4 (17‐87) Breast implant Allergan 592 (40.8) BMI 23.9 ± 4.1 (15.6‐40) brand Mentor 390 (26.9) Comorbidities Obese 56 (4.7) Polytech 133 (9.2) Diabetes 28 (2.4) Nagor 107 (7.4) Vascular disease 12 (1.0) Sebbin 15 (1.0) Hypertension 132 (11.1) B‐lite 4 (0.3) Hypothyroidism 78 (6.6) Silimed 1 (0.1) Other not defined 190 (16.0) Motiva 1 (0.1) comorbidities Not defined 182 (12.6) Smoking status Active smokers 120 (10.1) Expander 25 (1.7) Ex‐smokers 62 (5.2) Incisions Inverted‐T 109 (7.5) Use of drugs Immunosuppressants 7 (0.6) Round block 29 (2.0) Anticoagulants 26 (2.2) Inframammary fold 183 (12.6) Use of other not 197 (16.6) Lateral 609 (42.0) defined drugs Periareolar 99 (6.8) Previous surgery Quadrantectomy 81 (5.6) Elliptic 271 (18.7) (per breast) Lumpectomy 58 (4.0) Other 73 (5.0) Mastectomy 18 (1.2) Not defined 77 (5.31) Reconstruction 24 (1.7) Hospital stay, d 3.2 ± 2.7 (0.5‐21.0) Esthetic surgery 32 (2.2) Abbreviations: iBAG, International Braxon Audit Group; DCIS, ductal Type of tumor DCIS 256 (17.7) carcinoma in situi; IDC, invasive ductal carcinoma; ILC, invasive lobular (per breast) LCIS 14 (1.0) carcinoma; LCIS, lobular carcinoma in situ; NAC, nipple‐areolar complex; IDC 623 (43.0) RBS, red breast syndrome. a ILC 100 (6.9) Nineteen patients had chemotherapy but missing data on Multiples /mixed 77 (5.3) administration time. b Other 48 (3.3) Nine breasts had missing data about radiation treatments. c Twenty seven procedures had missing data on implant profile. None 298 (20.6) Chemotherapya Neoadjuvant 141 (11.9) Adjuvant 216 (18.2) A t‐test analysis revealed a significant difference in hospitalization Both treatments 34 (2.9) time mean for patients with hypothyroidism (P‐value = .016), with pre- Radiotherapyb Preoperative 42 (2.9) operative chemotherapy (P‐value = .004), patients who underwent ax- (per breast) Postoperative 153 (10.6) illary surgery (P‐value = .008), with postoperative chemotherapy (P‐ Both treatments 3 (0.2) value = .003) or radiotherapy (P‐value = .018). All these patients were Surgical (per breast) more likely to have longer hospital stay; also, the type of reconstruction Type of surgery Therapeutic 1118 (77.1) (one‐ or two‐stage) influenced hospital stay (P‐value = .001). Prophylactic 291 (20.1) Patients had a mean follow up period of 22.7 months (range Revision 41 (2.8) 3‐75.7): they were postoperatively checked in each clinic following Axillary dissection 187 (12.9) standard practice and patients’ complications were recorded and Mastectomies Nipple‐sparing 720 (49.7) treated during follow up visits. Complications were analyzed con- Skin‐sparing 466 (32.1) sidering the problem as breast‐related, not patient‐related, as each Skin‐reducing (NAC 81 (5.6) removal) breast has its own individual risk factors. For example, a patient who Skin‐reducing (NAC 19 (1.3) underwent a bilateral mastectomy and PPBR may need radiation preservation) therapy on one side and no therapy on the contralateral breast, this None 35 (2.4) way risk factors for postoperative complications would differ Not defined 129 (8.9) between the breasts. (Continues) 852 | MASIÀ ET AL. T A B L E 2 Complications, sorted by the timing of occurrence Early complications Late complications Total values (within 3 mo) (after 3 mo) Not defined Complications iBAG cohort: Breast Patients Breast Patients Breast Patients Breast Patients 1186 patients/1450 breasts (Nr)(%) (Nr)(%) (Nr)(%) (Nr)(%) (Nr)(%) (Nr)(%) (Nr)(%) (Nr)(%) Seroma 111 (7.7) 103 (8.7) 52 (3.6) 47 (4.0) 3 (0.2) 3 (0.3) 56 (3.9) 53 (4.5) Dehiscence 67 (4.6) 63 (5.3) 28 (1.9) 27 (2.3) 0 (0) 0 (0) 39 (2.7) 36 (3.0) Hematoma 31 (2.1) 31 (2.6) 20 (1.4) 20 (1.7) 0 (0) 0 (0) 11 (0.8) 11 (0.9) Necrosis 46 (3.2) 42 (3.5) 21 (1.4) 18 (1.5) 2 (0.1) 2 (0.2) 23 (1.6) 22 (1.9) Infection 70 (4.8) 64 (5.4) 25 (1.7) 23 (1.9) 5 (0.3) 5 (0.4) 40 (2.8) 36 (3.0) Extrusion 18 (1.2) 17 (1.4) 6 (0.4) 6 (0.5) 5 (0.3) 5 (0.4) 7 (0.5) 7 (0.6) RBS 48 (3.3) 46 (3.9) 17 (1.2) 16 (1.3) 1 (0.1) 1 (0.1) 30 (2.1) 29 (2.4) Fever 25 (1.7) 16 (1.3) 19 (1.3) 12 (1.0) 0 (0) 0 (0) 6 (0.4) 4 (0.3) Implant rotation 3 (0.2) 3 (0.3) 0 (0) 0 (0) 3 (0.2) 3 (0.3) 0 (0) 0 (0) Capsular contracture 31 (2.1) 26 (2.2) 5 (0.3) 4 (0.3) 17 (1.2) 14 (1.2) 9 (0.6) 8 (0.7) Rippling 40 (2.8) 30 (2.5) 7 (0.5) 4 (0.3) 25 (1.7) 19 (1.6) 8 (0.5) 7 (0.6) Other complications 48 (3.3) 46 (3.9) 11 (0.8) 9 (0.8) 6 (0.4) 6 (0.5) 31 (2.1) 31 (2.6) Implant loss 94 (6.5) 89 (7.5) 41 (2.8) 37 (3.1) 27 (1.9) 25 (2.1) 26 (1.8) 26 (2.2) Abbreviation: RBS, red breast syndrome. As shown in Table 2, a total of 200 breasts experienced immediate Infection instead is more likely to occur in diabetics (RR = 4.026; complications while late complications occurred in 61 breasts; 46.7% of P‐value = .003) and ex/active smokers (P‐value = .016) with RR = 2.15 the total complications had no records about their onset. Among all for ex‐smokers and 2.08 for active smokers. Axillary dissection also PPBR, the implant loss rate was 6.5%, while 76.2% of all complicated influenced infection onset (RR = 2.17; P‐value = .009) and an in- breasts were conservatively treated. Most of the implant losses occurred creasing implant volume showed, both in univariate and multivariate in the early period (41 breasts; 2.8% vs 27 breasts; 1.9%); moreover, analysis, a higher risk of infection development, with an infected immediate complications were mainly surgery‐related adverse events breast mean volume of 409.3 g compared to those of noninfected such as seroma, wound dehiscence, hematoma, skin necrosis and infec- cases of 346.2 g (P‐value = .001). Always regarding the infection oc- tion. On the other side, late complications are mostly represented by currence, statistical significance was highlighted both by univariate implant‐related problems, in particular, capsular contracture and rippling and multivariate analysis for the type of incision used (P‐value <.05) (Table 2). In a considerable number of patients, the timing of adverse except for the round‐block technique. events was not specified, so the complication timing was not included in Considering risk factors for wound dehiscence, multivariate the statistical analysis, focusing it on the total complication number and analysis demonstrated a high impact of active smoking habits on this on the risk factors affecting their occurrence. complication (RR = 2.49; P‐value = .001). Moreover, skin reducing Among the breasts that developed complications, most showed the mastectomy appeared to be more at risk of wound dehiscence incidence of a single adverse event (n = 284; 72.6%). In these cases, the (RR = 5.19; P‐value = .047) compared to nipple‐sparing mastectomy; removal of the implant was carried out in 17.6% (n = 50). Considering also the type of surgical incision chosen (P‐value <.05), particularly breasts suffering from two complications (n = 66; 16.9%), implant loss wise pattern, influenced wound dehiscence. rate raise at 30.3% (n = 20), while breasts that reported three or more Smoking status, immunosuppressive drugs and implant volume complications (n = 37; 9.5%) led to implant loss in more than half of the were risk factors involved in postoperative mastectomy flap necrosis cases (n = 22; 59.5%). Two women had the removal of the breast implant (P < .05); particularly, mean implant volume in complicated patients but no records on occurred complications were collected. was 406.8 g while for the other ones it was 347.3 g. The multivariate analysis of the risk factors contributing to compli- Active smokers and diabetics are prone to develop RBS cation onset underlined an increased risk of seroma formation in patients (respectively RR = 2.42, RR = 3.90; P‐value = .02); the presence of using immunosuppressive drugs (RR = 4.56; P‐value = .017) as well as a previous mastectomy has demonstrated a connection with RBS those who had had a previous esthetic breast surgery as well (RR = 6.55; P‐value = .044). The univariate analysis also (RR = 2.54; P‐value = .030) or an axillary dissection during the PPBR gave significance to the implant volume variable (P‐value = .004) (RR = 1.67; P‐value = .039); also the type of tumor seemed to increase although the multivariate did not confirm the value seroma onset (P‐value = .029). (P‐value = .058). MASIÀ ET AL. | 853 Capsular contracture was related to postoperative radiation ther- immediate one‐step PPBR are mainly from European clinical ex- apy (RR = 3.90; P‐value < .05) both in univariate and multivariate ana- periences, most of them performed with the use of Braxon ADM.3‐ 6,11‐13 lysis; moreover, this complication seems to be more common in patients From these publications a similar rate of implant loss is ob- having a PPBR for revision surgery (RR = 16.36; P‐value = .001) or served, set around 4%; an exception is represented by Vidya's mul- having had a previous breast augmentation (RR = 5.02; P‐value = .009) ticentre study, which reported 2% of failure rate on 100 cases; this or breast reconstruction (RR = 8.93; P‐value < .05). series was characterized by highly selected patients, with low asso- Patients were further divided into two subgroups: those ciated risk factors, and this could explain the low complication rate.11 undergone radiation therapies (pre‐ or postoperatively) and those The study by Reitsamer et al on 200 PPBR with implants wrapped not irradiated, to evaluate with a univariate analysis the potential either with ADM or synthetic mesh showed the following complication impact of this treatment on postoperative complications (Table 3). rate among the total reconstructed breasts in a 36‐months follow‐up: Through univariate analysis, it was investigated also if the adminis- 7% of necrosis, 4% of hematoma, 14.5% of seroma, 2.5% of implant tration time of radiation therapy, pre‐ or postoperatively, could re- rotation and 1.5% of rippling; lipofilling was required in 3.5% of the present a significant risk factor for complication development. women. Although complication rates in this study were quite higher Radiation therapy appeared to be a statistically significant risk factor than those reported in the iBAG study, we are not able to associate for the development of postoperative seroma, capsular contracture, them specifically with one of the two materials used to cover the rippling, and implant loss. Interestingly, at multivariate analysis, the implant, since the authors did not correlate outcomes with membrane negative impact of the postoperative treatment was confirmed only type.14 Instead, we are led to consider the surgical approach chosen as on capsular contracture, having no statistically significant association the critical factor impacting outcomes, since 79.5% of cases underwent with the occurrence of all other complications (Table 3). mastectomy through inframammary fold incision versus 13% of iBAG Six patients are shown in Figures 2‐4 as representative examples of experience. In fact, this surgical access reduces breast pocket visibility, PPBR esthetic outcomes. Each figure shows two cases with preoperative thus increasing the risk of accidental damage to nipple vascular plexus, and postoperative pictures in lateral and frontal views. thus explaining the higher rate of nipple‐areolar complex necrosis (7% vs 3.2% of the iBAG cohort). Even seroma incidence is doubled in Reitsamer's paper, when compared to 7% of the present study; this 4 | D I S C U S SI O N could be explained with the presence of chemical preservatives (Polysorbate 20) present in the ADM used, which may cause a higher Prepectoral ADM‐assisted breast reconstruction is growing in fame postoperative inflammatory reaction. An observation should be also among all European and American hospitals, with the aim of im- made on implant rotation rate, 12 times higher than that reported in proving patients’ esthetic and functional outcomes, such as their iBAG data, which may originate from the different wrapping techni- quality of life.5,6 The advantages of PPBR compared to the tradi- que: in fact, Reitsamer's approach involves only a frontal implant tional submuscular approach are well described in several publica- covering while iBAG study used an ADM able to create a whole tions, but lack of data from large cohorts of patients negatively “pocket” which tightly fits the anatomical profile of the breast implant affects the quality of scientific information. Moreover, inadequate and avoid implant rotation. information about the technique also affects the surgeon's judg- In Highton et al's15 and Chandarana et al's12 experiences, the ment for a correct patient selection, thus increasing the risk of rate of necrosis was found to be slightly higher than in the iBAG developing postoperative complications. The aim of this data col- collection, as they reported respectively 4.4% and 5.2% rates. Even lection was to obtain the largest evidence on PPBR performed with though the ADM used was the same as iBAG study, immediate and a complete Braxon ADM implant wrapping, to acquire unquestion- late complication rates of Chandarana's analysis were consistently able statement about PPBR outcomes and consequently lead to higher than ours (hematoma 6.9%, infection 6%, seroma 13.3%). In correct patient selection. our opinion, the differences in clinical and surgical details of the This retrospective multicentre study collected 1450 cases, thus populations between the two studies might have played a role in defining the largest database of ADM‐assisted PPBR patients; compli- adverse events occurrence. cation rates were acceptable and always below 8%, with an overall Overseas, studies have been published by American authors which reconstruction failure of 6.5%. Statistical analysis showed a higher risk have performed PPBR on larger cohorts, yet in a two‐stage procedure of developing postoperative complications for active smokers, diabetics, with the use of tissue expander covered with ADM positioned on the and patients who had had previous breast surgery or currently taking frontal part only.16 Moreover, the use of porcine ADM is still un- immunosuppressants; additionally, some surgical details such as implant common among the main American scientific papers, so that most evi- volume, type of skin incision or mastectomy seem to affect complication dence derives from human dermis such as AlloDerm.17 The analysis of rate. The adverse effect of postoperative radiation therapy was con- these studies should bring up concern on more aspects, the fact that firmed only on capsular contracture occurrence (RR = 3.90; P‐value two‐stage techniques require a second surgery to exchange the device <.05) resulting anyway with a low overall rate, set around 2%. with a definitive implant and the relative increased risk of tumor re- The few publications about one‐step PPBR reported outcomes in currence.18 In European daily practice, a direct‐to‐implant single‐stage line with the data raising from the iBAG study. Evidence about PPBR is preferably offered, since in most women a second procedure 854 | MASIÀ ET AL. F I G U R E 2 A‐C, Preoperative pictures in lateral and frontal view, slight asymmetry of the right breast due to a previous clinical investigation; D‐F outcomes at 21 months of unilateral right nipple‐sparing mastectomy and prepectoral breast reconstruction with Braxon; G‐I, preoperative lateral and frontal views of an IDC left case; J‐L, outcome of left immediate prepectoral reconstruction after nipple‐sparing mastectomy and right breast augmentation, 7 months postop. IDC, invasive ductal carcinoma [Color figure can be viewed at wileyonlinelibrary.com] MASIÀ ET AL. | 855 F I G U R E 3 A‐C, Preoperative lateral and frontal views; D‐F, 12 months postop outcomes of left immediate prepectoral breast reconstruction; G‐I, frontal and lateral views of right IDC case; J‐L, 7 months from the bilateral prepectoral reconstruction after nipple‐sparing mastectomies [Color figure can be viewed at wileyonlinelibrary.com] 856 | MASIÀ ET AL. F I G U R E 4 A‐C, Preoperative lateral and frontal pictures of a right DCIS case; D‐F, esthetic result after 6 months of right immediate prepectoral reconstruction; G‐I, preoperative lateral and frontal pictures of a failure of previous left breast reconstruction; J‐l, outcomes of left delayed prepectoral breast reconstruction, 24 months postoperative. DCIS, ductal carcinoma in situ [Color figure can be viewed at wileyonlinelibrary.com] MASIÀ ET AL. | 857 can be easily spared. Moreover, multiple surgeries are associated with a direct‐to‐implant (DTI) PPBR. With regard to the impact of radio- an increased infection risk which could find confirmation in higher in- therapy on PPBR outcomes, the iBAG study collected 190 irradiated 19 fection rates reported in the main American PPBR experiences. In patients for a total of 198 DTI‐PPBR, which to our knowledge represent fact, Nahabedian reported very high infection rates (12.8% by patient; the largest evidence on this issue. The outcomes in Table 3 demonstrated, 8.1% by breast) not in line with iBAG study outcomes, while implant loss especially for postoperative RT, no association with the onset of post- rate was similar (6.5%) and slightly different necrosis and seroma rates operative complications, except for capsular contracture. 17 (9.7% and 4.8%). High implant and expander loss rate, as well as The retrospective review by Elswick et al about irradiated PPBR infection one, were also found in Bettinger and Schnarrs publications collected the largest number of patients published up to now but with about prepectoral expander/implant reconstructions, with overall just 9 months of follow‐up; in this study, RT was found not to have any infection rates of 9.1% for the first one and 11.8% for the second, statistical association with adverse event occurrence, despite the overall 20,21 reinforcing again our hypothesis. higher rates of complications in the irradiated group vs the non- Furthermore, patient's risk factors revealed by our statistical ana- irradiated one (25.9% vs 23.1%): infection rate was high in both groups lysis find confirmations in other publications: Schnarrs highlighted (18.5% vs 7.7%), as in most American publications on PPBR. Capsular higher postoperative complications risk in smokers and patients with contracture rate was higher in the irradiated group (1.9% vs 0%), as we 20 >500 g breasts, while Bettinger observed increased complication rates observed in iBAG experience (5.1% vs 1.7%); the slightly different in previously irradiated breasts and no significant association between percentage could be probably due to the different distribution of the chemotherapy and postoperative adverse events.21 iBAG population, which was richer in smokers (7.9%), diabetics (1%) and In iBAG analysis a secondary interest was to investigate RT impact patients with hypothyroidism (7.1%), when compared to Elswick's on postoperative outcomes; the multivariate analysis did not reveal any review, or due to the shorter follow‐up of this review.24 statistically significant correlation between RT and postoperative com- In the same year, the publication by Sinnott et al25 compared plications, except for capsular contracture, that even so did not reach a irradiated and nonirradiated patients, stratified by prepectoral or high percentage (about 5%) (Table 3). Very few publications until now subpectoral procedure; the subpectoral reconstruction showed have focused their studies on PPBR and RT and moreover their popu- overall higher capsular contracture rate than PPBR (9.8% vs 5.2%), lations were limited to small cohorts with a maximum of 54 patients especially in irradiated breasts (52.2% vs 16.1%), confirming the undergone unilateral RT.22‐24 Even in these series the authors had ex- ability of ADM to prevent from capsular contracture and the effec- perienced only with the two‐stage reconstructive procedure and not with tiveness of prepectoral implant positioning vs the submuscular one. T A B L E 3 Comparison of irradiated and nonirradiated breasts developing postoperative complicationsa Nonirradiated Irradiated Nr = 198 breastsb Preop RT Nr = 45 breastsc Postop RT Nr = 159 breastsc Nr = 1243 breasts Complications Nr (%) Nr (%) RR P‐value Nr (%) RR P‐value Nr (%) RR P‐value Seroma 87 (7.0) 22 (11.1) 1.53 .042 5 (11.1) 1.52 .363 17 (10.7) 1.49 .100 Dehiscence 56 (4.5) 8 (4.0) 0.91 .768 1 (2.2) 0.49 .461 7 (4.4) 1.02 .951 Hematoma 27 (2.2) 4 (2.0) 0.97 .948 0 (0.0) 0.00 .320 4 (2.5) 1.23 .662 Necrosis 38 (3.1) 8 (4.0) 1.28 .465 2 (4.4) 1.41 .630 6 (3.8) 1.21 .632 Infection 59 (4.7) 10 (5.1) 1.06 .852 2 (4.4) 0.92 .910 8 (5.0) 1.09 .810 Extrusion 13 (1.0) 5 (2.5) 2.05 .082 3 (6.7) 5.63 <.05 2 (1.3) 1.08 .906 RBS 44 (3.5) 4 (2.0) 0.60 .268 0 (0.0) 0.00 .205 4 (2.5) 0.76 .565 Fever 24 (1.9) 1 (0.5) 0.29 .153 0 (0.0) 0.00 .364 1 (0.6) 0.36 .265 Implant rotation 3 (0.2) 0 (0.0) 0.00 .489 0 (0.0) 0.00 .755 0 (0.0) 0.71 .545 Capsular contracture 21 (1.7) 10 (5.1) 2.42 .002 0 (0.0) 0.00 .312 10 (6.3) 3.10 <.05 Rippling 39 (3.1) 1 (0.5) 0.18 .036 1 (2.2) 0.79 .817 0 (0.0) 0.00 .025 Other complications 39 (3.1) 9 (4.5) 1.38 .305 2 (4.4) 1.35 .675 7 (4.4) 1.36 .401 Implant Loss 70 (5.6) 22 (11.1) 1.83 .003 5 (13.3) 1.83 .189 17 (10.7) 1.80 .014 Note: 2. Nr. 6 breasts had data about preoperative treatment but no evidence about the postoperative therapy; Nr. 2 breasts had data about postoperative radiation but no details about preoperative treatment. Abbreviation: RBS, red breast syndrome. a Nr. 9 breasts had no data on radiation therapy. b Nr. 6 breasts had data about preoperative treatment but no evidences about the postoperative therapy; Nr. 2 breasts had data about postoperative radiation but no details about preoperative treatment. c Nr. 3 breasts had both treatments, pre and postoperative. 858 | MASIÀ ET AL. Prepectoral and submuscular breast reconstruction were also number of irradiated patients so that to draw more stable conclusions in evaluated by Sbitany and colleagues comparing irradiated and not‐ this interesting subgroup of patients. irradiated breasts from a single center experience; the two groups undergoing postmastectomy RT revealed different complication rates with overall higher rates in PPBR group. Infection represented 5 | CON CLUSIONS again the highest issue (42.4% in PPBR vs 32.2%), followed by ex- plant rate (15.4% in PPBR vs 19.3%), wound dehiscence (15.4% in The iBAG study brings the largest evidence on PPBR, collecting the PPBR vs 12.9%), skin necrosis (26.9%, in PPBR vs 9.7%), seroma and experience of 30 hospital centers in a 6‐year period. The audit col- hematoma (both 7.7%. in PPBR vs 3.2%). Despite the high incidence lected homogeneous data on 1450 procedures carried out by wrap- of complications, no statistical evidence of influence between post- ping the implant with a preshaped porcine ADM; data analysis 26 mastectomy RT and PPBR outcomes were observed. highlighted lasting results with low complication rates and defined The role of ADM in the prevention of periprosthetic fibrosis was the risk factors involved in the onset of postoperative complications. evaluated in several papers, also before the conception of PPBR, and its The iBAG multicentre data collection represents a milestone in the positive effect was confirmed in mutual agreement.27,28 Moreover, the field of breast reconstruction, extensively improving the knowledge 4 study by Onesti et al described the specific behavior of the ADM of this procedure. Further prospective studies are expected to Braxon confirming, through ultrasound and histologic examinations, the achieve a clearer picture of a patient's satisfaction and the impact of formation of a new layer in the subcutaneous tissue that is less prone to radiotherapy on the outcomes of prepectoral reconstruction. contract during the years. Nevertheless, in some recent publications on PPBR, the ADM implant covering has been questioned again. The study iBAG W ORKI NG G ROU P 29 by Salibian et al proposed a staged subcutaneous reconstruction Marzia Salgarello, MD, Department of Plastic Surgery and without any expander cover, but it revealed 7.6% of capsular con- Reconstructive Surgery, Fondazione Policlinico Universitario Agos- tracture (Baker III and IV) in a series of 155 patients (250 breasts) tino Gemelli IRCCS, Università Cattolica del Sacro Cuore (Rome – IT). reconstructed with a “naked” prepectoral expander. The same doubt Leonardo Cattelani, MD, Breast Surgery Unit, University Hospital of about the need of ADM to cover the implant in PPBR was the basis of Parma (Parma – IT). Pier Camillo Parodi, MD, PhD, Department of the retrospective study by Singla et al30 from the analysis of the im- Plastic and Reconstructive Surgery, Azienda Ospedaliero‐ mediate single‐stage subcutaneous reconstructions carried out without Universitaria “Santa Maria della Misericordia” (Udine – IT). any coverage of the silicone implant raised the following complications Diego Ribuffo MD, Plastic Surgery Unit, Department of Surgery "P. rate: 15.3% of seroma, 15.3% of infections, 11.5% of implant rotation, Valdoni", Sapienza University (Rome – IT). Maria Giuseppina Onesti, 3.8% of capsular contracture and 19.2% of implant visibility and contour MD, Plastic Surgery Unit, Department of Surgery "P. Valdoni", defects; far from the results of iBAG data collection. These results lead Sapienza University (Rome – IT). Giorgio Berna MD, Plastic and us to consider the complete ADM cover a crucial point in PPBR to Reconstructive Surgery Department, “Ca’ Foncello” General Hospital, reduce the risk of periprosthetic fibrosis. AULSS2 Marca Trevigiana (Treviso – IT). Simon J. Cawthorn MD, In conclusion, the iBAG data collection represents the largest Southmead Hospital Bristol, North Bristol NHS Trust (Bristol – UK). study on PPBR performed using a complete implant wrapping with a Fernando Bozza MD, Breast Care Center, IOV Istituto Oncologico preshaped porcine ADM. Data from this retrospective multicentre Veneto ‐ IRCCS (Padova – IT). Stefano Duodeci MD, Breast Unit, audit confirm the effectiveness of the technique and the low post- Hospital of Cittadella, AULSS6 Euganea (Padova – IT). Simon Harries operative complication rate, especially capsular contracture; more- MD, Warwick Hospital, South Warwickshire NHS Foundation Trust over, an ideal patient profile has been drawn by assessing the risk (Warwick – UK). Maurizio Governa MD, Department of Plastic and factors involved in postoperative complications’ onset. Reconstructive Surgery, Azienda Ospedaliera Universitaria Integrata The authors agree to consider this study limited by its retrospective (Verona – IT).Roberto A. Barmasse MD, Unit of Thoracic and Breast nature, especially for those patient's characteristics and intraoperative Surgery, “Umberto Parini” General Hospital (Aosta – IT). Raghavan details that were collected in a percentage too small to reach the value Vidya MD, New Cross Hospital, Royal Wolverhampton NHS Trust sufficient for the statistical analysis and which in the future should be (Wolverhampton – UK). Tapan Sircar MD, New Cross Hospital, Royal further investigated to better describe the correct patient selection. For Wolverhampton NHS Trust (Wolverhampton – UK). Harleen Deol this reason, a prospective study is planned: starting from the outcomes MD, East and North Hertfordshire NHS Trust (Welwyn Garden City – of this large data collection on PPBR we will analyze the impact of a UK). Tommaso Guzzetti MD, Plastic Surgery Unit, ASST "Alessandro more careful patient selection on the postoperative complication as well Manzoni" Hospital (Lecco – IT). Fabrizio Meggiolaro MD, Breast Unit, as implant loss rate. A prospective evaluation of the effect of radio- Mirano Hospital, AUSSL3 Serenissima (Venezia – IT). Mauro Schiavon therapy is planned too. Other limits of this study were that esthetic and MD, Department of Plastic and Reconstructive Surgery, Azienda patient‐reported outcomes were not reported and that postoperative Ospedaliero‐Universitaria “Santa Maria della Misericordia” (Udine – pain scores were available only for a minority of patients so that could IT). Rishikesh Parmeshwar MD, Department of Breast and General not be included as an outcome measure. This leaves room for further Surgery, University Hospitals of Morecambe Bay NHS Foundation discussion of results, in particular in a longer follow‐up and a greater Trust (Lancaster – UK). Douglas Ferguson MD, Royal Devon and MASIÀ ET AL. | 859 Exeter Hospital, Royal Devon and Exeter NHS Foundation Trust of Plastic Surgery, Spedali Civili Brescia, University of Brescia (Exeter – UK). Caroline Mortimer MD, Ipswich Hospital, East Suffolk (Brescia – IT). and North Essex NHS Foundation Trust (Ipswich – UK). Giorgio Manca MD, Department of Plastic Surgery, Spedali Civili Brescia, University of AC KNO WL EDG M EN TS Brescia (Brescia – IT). Dinesh Thekkinkattil MD, Department of The authors thank IIB and INPECS societies to have monitored the Oncoplastic Breast Surgery, Pilgrim Hospital and Lincoln County study project and for the constant participation and support in data Hospital, United Lincolnshire Hospitals NHS Trust (Lincoln – UK). collection and analysis. Rathinasabapathy Rathinaezhil MD, Park Centre for Breast Care, Brighton and Sussex University Hospitals NHS Trust (Brighton – UK). CON F LI CT OF IN TE RES T S Pud Bhaskar MD, University Hospital of North Tees, North Tees and The authors declare that there are no conflict of interests. Hartlepool NHS Foundation Trust (Stockton‐on‐Tees – UK). Nicola Roche MD, The Royal Marsden Hospital, The Royal Marsden NHS Foundation AU TH OR CO NTRIB UTION S Trust (Chelsea, London – UK). Alberto Rivarossa MD, Department of All the participant to the iBAG study must be considered author of Plastic and Reconstructive Surgery, “Santa Croce e Carle” Hospital the study. They all had substantial contributions to the design of (Cuneo – IT). Gonzalo De Castro Parga MD, PhD, Breast Surgery, work, drafted work, made the final approval, and agreed to be University Hospital Complex of Vigo CHUVI (Vigo ‐ ES). Samuele accountable for all aspects of the work. Massarut MD, Breast Surgery Unit, CRO National Cancer Institute (Aviano – IT). Susanna Polotto MD, Breast Surgery Unit, University D A TA A V A I LA B I L I T Y S T A T E M E N T Hospital of Parma (Parma – IT). Mattia Di Bartolomeo MD, Department The data that support the findings of this study are available from the of Plastic Surgery and Reconstructive Surgery, Fondazione Policlinico corresponding author upon reasonable request. Universitario Agostino Gemelli IRCCS, Università Cattolica del Sacro Cuore (Rome – IT). 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