Gdalevitch, Perry M.D.; Ho, Adelyn M.D.; Genoway, Krista M.D.; Alvrtsyan, Hasmik M.S.; Bovill, Esta M.D., Ph.D.; Lennox, Peter M.D.; Van Laeken, Nancy M.D.; Macadam, Sheina M.D.
Prosthetic breast reconstruction is the most common method of postmastectomy reconstruction.1 Traditional tissue expander/implant reconstruction is a process that requires two procedures to complete. In Canada, operating room time for breast reconstruction is limited, resulting in centers having to prioritize either immediate or delayed reconstructive cases.2,3 Achieving immediate implant-based breast reconstruction in a single stage would eliminate the need for a second operation and potentially free additional resources for breast reconstruction.
Acellular dermal matrix is a biomaterial that can be used to achieve immediate prosthetic breast reconstruction in a single stage with successful outcomes and an acceptable complication profile.4–9 First introduced in 2005 by Breuing and Warren,4 direct-to-implant immediate prosthetic breast reconstruction using acellular dermal matrix has been used in patients who are candidates for traditional two-stage implant reconstruction. To date, a number of studies have compared the complication profile and cost effectiveness of single- versus two-stage prosthetic reconstructive techniques.6–16 Cost analysis has shown that direct-to-implant reconstruction using acellular dermal matrix is cost-effective compared with traditional two-stage implant reconstruction when performed in a single stage.12 Guidelines for appropriate patient selection for this new procedure do not exist in the literature.
The purpose of this study was to identify clinical predictors of failed direct-to-implant single-stage immediate breast reconstruction using acellular dermal matrix, defined as the need for early revision recognized within the first 6 months postoperatively. These predictors will help screen patients most likely to achieve successful reconstruction in a single stage. The secondary objective was to compare the rates of complications in patients with direct-to-implant single-stage immediate versus two-stage breast reconstruction at our institution. Finally, we sought to look at aesthetic outcomes of direct-to-implant single-stage immediate breast reconstruction patients.
PATIENTS AND METHODS
The study was undertaken with the approval and oversight of the University of British Columbia Institutional Research Ethics Board. All patients that underwent skin-sparing or nipple-sparing mastectomy followed by direct-to-implant single-stage immediate breast reconstruction in 2010 and 2011 at three university-affiliated centers were included in the study. Reconstruction was performed by four members of the University of British Columbia Breast Program. Mastectomy was performed by five University of British Columbia general surgeons. Patients were excluded if they underwent a two-stage implant reconstruction with or without acellular dermal matrix and if they had less than 6 months of clinical follow-up. A random sample of control patients with two-stage alloplastic reconstruction without acellular dermal matrix performed between 1998 and 2011 at the same institution was used for comparison of demographics and complications.
The primary outcome was failed direct-to-implant single-stage immediate breast reconstruction. This was defined as a reconstruction requiring early revision surgery under general anesthetic identified within the first 6 months postoperatively. This threshold was selected to minimize inclusion of revisions related to implant reconstruction in general, and isolate reasons for failure of the single-stage technique. Revisions were deemed necessary if they met the Canadian Medical Services Provider’s requirements: capsular contracture greater than or equal to Baker grade III,17 significant asymmetry of 150 g or greater, or significant malposition impeding the patient’s ability to wear a brassiere. Successful direct-to-implant single-stage immediate breast reconstruction was defined as a reconstruction completed with a single general anesthetic with or without minor revisions under local anesthetic.
Data were collected retrospectively from patient medical records for direct-to-implant single-stage immediate breast reconstruction patients. Before data collection, risk factors for failed reconstruction were determined a priori based on literature review and surgeon experience. These included age, body mass index, medical comorbidities, smoking status, history of preoperative irradiation, history of chemotherapy, preoperative bra size, laterality, preoperative breast measurements (i.e., breast size, breast width, breast height, breast projection, nipple-areola complex to sternal notch, nipple-areola complex to inframammary fold, and degree of ptosis), skin quality, pathologic findings, operative details (i.e., mastectomy surgeon, mastectomy weight, implant type and size, and acellular dermal matrix size and thickness), and postoperative irradiation. Basic demographic information was collected retrospectively for patients in the two-stage sample control group.
Additional clinical information collected for single-stage and two-stage patients included the following: dates and details of postoperative course including early complications (i.e., infection, seroma, hematoma, mastectomy flap necrosis, and reaction to acellular dermal matrix) and long-term follow-up results (i.e., implant malposition, volume asymmetry, and capsular contracture). Aesthetic outcome for direct-to-implant single-stage immediate breast reconstruction patients was assessed by breast, with both preoperative and postoperative photographs by two independent plastic surgeons using an ordinal Likert scale (where 1 = poor, 2 = fair, 3 = good, 4 = very good, and 5 = excellent), as described previously.11 Evaluators were asked to compare the postoperative breast to its preoperative appearance, to isolate the aesthetic outcome of this technique, independent of the contralateral procedure.
The distribution of continuous variables was examined using distributional plots. Means and frequencies were calculated for continuous variables and categorical data, respectively. Descriptive statistics were calculated for the patient and clinical characteristics of patients in the two groups, defined as successful and failed single-stage breast reconstruction with acellular dermal matrix, and for the control group. For normally distributed continuous variables, the t test was used to compare groups. Nonnormal continuous variables were compared using the Wilcoxon rank sum test. Categorical variables were compared using the Pearson chi-square test or the Fisher’s exact test. Interrater reliability for aesthetic scoring was calculated with a weighted kappa coefficient. The kappa statistic was interpreted as follows: greater than 0.75, excellent reproducibility; 0.40 to 0.74, good reproducibility; and less than 0.40, poor reproducibility.18
With failed single-stage as the dependent variable, univariate logistic regression analysis was performed to evaluate the association between patient-level and breast-level predictors of outcome and the dependent variable. Confounders of the outcome were controlled for using multivariate logistic regression. Model adequacy was determined by calculating the discrimination (C statistic) of the model. All analyses were carried out using the statistical program Stata 11.0 (StataCorp LP, College Station, Texas). Statistical significance was set at an alpha level of 0.05.
One hundred fourteen patients (164 breasts) underwent direct-to-implant single-stage immediate breast reconstruction during the study period. Fifty-two breasts (31.7 percent) in 43 patients (37.8 percent) met the criteria for failed direct-to-implant single-stage immediate breast reconstruction and required early revision surgery. Of these, 21 (48.8 percent) were unilateral and 22 (51.2 percent) were bilateral. All demographic variables were similar in the successful and failed single-stage groups (Table 1). The direct-to-implant single-stage cohort was similar to the two-stage without acellular dermal matrix control group (n = 312) for most demographic variables. The single stage cohort had a shorter median follow up time (228 days versus 1009 days; p < 0.001), a lower mean body mass index (22.2 versus 23.2; p = 0.01), had fewer patients who received post operative radiation compared to the two-staged control group (16.4 percent versus 25 percent; p = 0.02) (Table 2).
Predictors for failure of direct-to-implant single-stage immediate breast reconstruction are listed in Table 3. The failed and successful groups differed for distribution of preoperative bra size and disease severity. Breasts with bra sizes B, C, and D were found to have increasingly higher early revision rates compared with breasts of size A on univariate analysis (OR for bra size B, 4.49; C, 5.67; D, 5.78; p = 0.031). Breasts with bra size D also had higher rates of mastectomy flap necrosis compared to smaller bra size (D, 50.0 percent; A, 13.8 percent; p = 0.03). The corresponding mean mastectomy weight and mastectomy flap necrosis rate for bra sizes A to D are shown in Table 4.
In the failed single-stage group, breasts undergoing prophylactic mastectomy and reconstruction had a trend toward a lower revision rate compared with breasts undergoing therapeutic mastectomies (32.7 percent versus 46.4 percent; p = 0.06). Likewise, failure of direct-to-implant single-stage immediate breast reconstruction was less likely in breasts with benign disease (25 percent versus 35.7 percent; p = 0.043). Implant shape, mastectomy surgeon, incision type, mastectomy type, breast measurements, ptosis, radiation and acellular dermal matrix size were not found to be statistically significant predictors on univariate analysis.
Logistic regression was performed by breast with single-stage failure as the dependent variable to determine predictors of direct-to-implant single-stage failure. Larger breasts sizes (B, C, and D) were found to have increasingly higher revision rates compared with breasts of size A (OR for bra size B, 4.86; C, 4.96; and D, 6.01; p < 0.05) after controlling for smoking, laterality, irradiation, and prophylactic mastectomy (C statistic, 0.68). Breasts operated on for prophylactic reasons trended toward a decreased likelihood of surgical revision in this model (OR, 0.47; p = 0.061), whereas a history of smoking trended toward an increased likelihood of single-stage failure (OR, 1.8; p = 0.065). Laterality and irradiation were not found to be statistically significant in predicting direct-to-implant single-stage immediate breast reconstruction failure in this cohort (Table 5).
Early (≤2 weeks postoperatively) complications including hematoma, seroma, infection, and mastectomy flap necrosis occurred in 47.5 percent (n = 78) of direct-to-implant single-stage immediate reconstruction cases and were more common in the failed group (67.3 percent versus 38.4 percent; p = 0.035). Early complications in the single-stage and two-stage control groups were similar, except for mastectomy flap necrosis, which occurred more frequently in direct-to-implant single-stage immediate breast reconstruction (28.7 versus 12.2; p < 0.001) (Table 6).
The overall early revision rate of the direct-to-implant single-stage immediate breast reconstruction patients was 31.7 percent (n = 52), with capsular contracture [n = 18 (11 percent)] and malposition [n = 18 (11 percent)] being the most likely reasons for failure of single-stage reconstruction (Table 7). In the two-stage control group, the long-term revision rate was 31.4 percent (n = 132), with the most common reasons being capsular contracture [n = 53 (12.8 percent)] and volume asymmetry [n = 37 (8.9 percent)].
Sixty-two percent of direct-to-implant single-stage immediate patients had preoperative and postoperative photographs available for aesthetic outcome rating. Aesthetic outcome was significantly better in the success group compared with the failed group (mean, 4.01 versus 3.38; p < 0.001). The kappa coefficient of 0.79 (95 percent CI, 0.68 to 0.85) indicated excellent agreement between the two independent raters. Sample photographs of poor to excellent results are shown in Figures 1 through 5.
Traditional prosthetic breast reconstruction consisting of a two-stage tissue expander-implant procedure is the most widely practiced technique in postmastectomy breast reconstruction.1 Disadvantages of this technique include two operations, multiple office visits for expansion, pain after expansion, and significant capsular adjustment at the time of implant exchange. Despite these disadvantages, this technique is safe and predictable and allows for good aesthetic results.19–21
Acellular dermal matrices were introduced into clinical practice to aid in a variety of surgical problems, including complex abdominal wall reconstruction,22 facial paralysis,23 and dural defects.24 In 2001, Duncan reported the first use of acellular dermal matrix in breast surgery to correct persistent implant rippling in both aesthetic and reconstructive cases.25 In 2006, Salzberg reported experience using acellular dermal matrix to achieve a single-stage implant reconstruction with full implant coverage.6 Since then, direct-to-implant single-stage immediate breast reconstruction has gained significant popularity as an elegant single-stage solution to postmastectomy prosthetic breast reconstruction.26–32 In addition to completing breast reconstruction in a single stage, the benefits of acellular dermal matrix include improved control of the breast pocket, augmentation of soft-tissue coverage in the lower pole, and a postulated decrease in capsular contracture.33–36 Despite the expense of acellular dermal matrix, cost analysis at our institution showed that breast reconstruction with acellular dermal matrix was cost effective compared with traditional two-stage reconstruction when performed in a single stage.12
Single-stage prosthetic breast reconstruction using acellular dermal matrix has widespread implications for patients and the health care system. It has the potential to decrease surgical morbidity, surgical wait times, and operative costs. Thus, it is important to accurately identify patients who are likely to have successful outcomes following direct-to-implant single-stage immediate breast reconstruction. An intraoperative algorithm based on flap thickness and quality of skin has been suggested to guide use of this technique.7,8 It has also been advised that immediate implant-based reconstruction with or without the use of acellular dermal matrix should be used with caution in large, ptotic breasts and in patients with a history of irradiation.37 Preoperative patient selection criteria specific to direct-to-implant single-stage immediate breast reconstruction using acellular dermal matrix do not exist in the literature.
Between 1998 and 2011, we performed traditional two-stage reconstruction without acellular dermal matrix in all alloplastic cases. Beginning in 2010, we introduced direct-to-implant single-stage immediate reconstruction using acellular dermal matrix after approval of our cost analysis favoring alloplastic reconstruction performed in a single stage. In this study, we analyzed our direct-to-implant single-stage immediate cohort and found that patients with smaller breasts (A cup, 190-g mean mastectomy weight) were less likely to require an early surgical revision (in effect, converting them to a two-stage procedure) compared with patients with larger breast sizes (B, 343 g; C, 456 g; and D, 597 g). The likelihood of single-stage failure increased with every cup size (OR of failure for bra size B, 4.86; C, 4.96; and D, 6.01; p < 0.05). Smaller breast reconstructions fared better in this cohort likely because of better skin quality, less aggressive mastectomy incisions and/or skin excision, and healthier mastectomy flaps. Larger breasts had significantly more mastectomy flap necrosis (OR for size D, 6.25; p = 0.027), which may have contributed to the higher early revision rate. Larger breasts may also have required more revisions as a result of using larger implants for reconstruction, producing added tension on the skin and accelerated envelope stretch with implant displacement.
Prophylactic mastectomy patients had a trend toward lower revision rates compared with therapeutic mastectomies (OR, 0.47; p = 0.061). Our clinical experience indicates that prophylactic cases may have better outcomes with this single-stage technique secondary to less aggressive mastectomies in a younger patient population. A trend toward a single-stage failure was also found with a history of smoking in this multivariate model (OR, 1.8; p = 0.065).
We compared our direct-to-implant single-stage immediate cohort’s complications to those of our two-stage control group. Complication rates of infection, seroma, hematoma, and capsular contracture were similar and consistent with the complication rates reported in the literature.9 Mastectomy flap necrosis in the direct-to-implant single-stage immediate cohort was significantly higher than that in the two-stage control group (28.7 percent versus 12.2 percent), as would be expected because of the skin-preserving nature of the single-stage technique and the added tension on the mastectomy flap from the effect of the implant.
The early breast revision rate in direct-to-implant single-stage immediate breast reconstruction patients was 31.7 percent, which is slightly higher than the revision rate of 28.6 percent recently reported in a small direct-to-implant single-stage immediate breast reconstruction series by Roostaeian.38 In the largest series by Salzberg et al., an overall revision rate of 19.1 percent can be deduced by combining elective revisions (15.2 percent) with revisions resulting from complications (3.9 percent).7 Given that this cohort represents our early experience using acellular dermal matrix, our higher early revision rate may be attributable to the learning curve associated with this technique. Our early revision rate did decrease slightly from 2010 (34.9 percent) to 2011 (29.6 percent). One of the most common reasons for early revision in the direct-to-implant single-stage immediate breast reconstruction group was Baker grade III capsular contracture (34.6 percent of failed single-stage cases). Despite the postulated hypothesis that acellular dermal matrix may prevent or alleviate capsular contracture, this remains one of the most likely causes for revision in our cohort. The other most common reason for revision in the single-stage cohort was malposition (34.6 percent of failed single-stage cases). This is likely because of the challenge of correctly setting the position of the inframammary fold in a single stage and may explain why the rate of revision for malposition was statistically lower in the two-stage control group (5 percent versus 11 percent; p = 0.01). However, the rate of revision because of volume asymmetry was significantly higher in the two-stage control group (8.9 percent versus 3 percent; p = 0.01), likely because of longer follow-up and possible changes in body weight or contralateral breast size over time.
Despite the high early revision rate in single-stage patients, the mean aesthetic outcome in the failed single-stage group was 3.38 of 5, where 3 is considered a good result (Fig. 3). This may be a reflection of higher patient expectations with single-stage breast reconstruction, as these patients no longer endure the absence of a breast mound and are less cognizant of the complexities involved in achieving their reconstruction.
The main limitation of this study is the small cohort size and the small number of breasts with postoperative irradiation. Irradiation was not found to be statistically different between the successful and failed single-stage groups, likely because of the small number of irradiated patients in this cohort [32 breasts (18.9 percent)]. In a larger group of patients, we would expect therapeutic mastectomies, smoking, and preoperative/postoperative irradiation to be statistically significant as predictors of single-stage failure.
Another limitation in Canada is the size of acellular dermal matrix being used in direct-to-implant single-stage immediate breast reconstruction. The majority of the reconstructions in this series were performed using a single 6 × 16-cm thick piece of AlloDerm (LifeCell Corp., Branchburg, N.J.). Cost analysis at our institution revealed this was the maximal size that could be used to maintain cost efficiency over the two-stage technique.11 This may explain why patients with very large breasts (DD and E), patients with higher body mass indices (≥35), and patients who want to significantly increase their cup size are not currently being offered direct-to-implant single-stage immediate breast reconstruction at our institution.
Although we did not have a matched control group for comparison, this study cohort’s early revision rate of 31.7 percent is similar to the 31.4 percent long-term revision rate of two-stage reconstructions at our institution. Given these data, it can be safely assumed that the early revision rate of the two-stage control group (median follow-up, 1009 days) would be significantly less than our study cohort’s (median follow-up, 228 days). We chose to focus on early revisions in direct-to-implant single-stage immediate reconstruction to identify patients who are requiring a second stage to achieve their reconstruction, resulting in unnecessary use of acellular dermal matrix. We will continue to follow our direct-to-implant single-stage immediate breast reconstruction cohort for long-term revision rates. However, given that long-term issues with implant reconstruction are intrinsic to the prosthesis, one would expect long-term outcomes of different alloplastic techniques to be similar.
Direct-to-implant single-stage immediate breast reconstruction offers many advantages to both patients and the health care system. Correctly identifying patients most likely to have a successful outcome in a single stage will allow health care providers to better allocate health care resources. In this study, we present our early experience with direct-to-implant single-stage immediate breast reconstruction and have found that increasing breast size is a predictor of single-stage failure. Patients with smaller breasts had successful single-stage outcomes. Women with larger breast sizes were more likely to require early revision, effectively converting them to a two-stage procedure. Given the expense of acellular dermal matrix, our study indicates that it may be more cost-effective for larger breasted patients to be offered the two-stage technique. The results of our early experience will help surgeons introducing acellular dermal matrix into their practice to select appropriate patients for direct-to-implant single-stage immediate breast reconstruction. A larger study cohort and longer follow-up times are required to identify additional predictors of short- and long-term success using this single-stage technique.
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