Are Large Intraoperative Fill Volumes Associated With Increased Complications After Tissue Expander Placement?

As skin- and nipple-sparing mastectomies have become routine in the treatment of breast cancer, immediate 2-stage breast reconstruction is a common option for breast cancer patients.^1,2 The benefits of immediate tissue expansion for 2-stage breast reconstruction include shorter operative time and hospital stay as well as improved aesthetic outcomes compared with those of delayed breast reconstruction.^3,4 Additionally, patients undergoing tissue expansion and concomitant administration of chemotherapy or radiation have an acceptable risk profile.^5,6

During the first stage of the procedure with tissue expander placement, higher intraoperative percent fill has been identified as a risk factor for complications.^7,8 This is largely attributed to the increased risk of decreased distal perfusion as a result of microvascular compression.⁹ Smoking status, increased body mass index (BMI), and age have also been reported as factors predisposing patients to increased complications after breast reconstruction with tissue expander placement.^10-13

To avoid overfilling, it is suggested that conservative tissue expander volumes be used for patients with greater risk profiles.¹³ However, previous studies have demonstrated that high intraoperative fill volume is not independently associated with increased complications.^9,14 A high initial fill volume may also result in a more natural appearing breast contour after mastectomy.¹⁵

More information regarding the outcomes of higher fill volumes is needed to individualize reconstructive options and assess the overall risk. The aim of the current study was to evaluate if a higher intraoperative tissue expander fill volume is associated with higher complication rates in patients undergoing immediate breast reconstruction with tissue expander placement.

After institutional review board approval was obtained, the electronic medical records of all patients (ages 18-85 years) who underwent unilateral or bilateral immediate implant-based breast reconstruction from January 2016 through December 2018 at the authors’ institution were reviewed retrospectively. Patients who did not have at least 3 months of follow-up or who were lost to follow-up were excluded from the study. The mastectomies were performed by 1 of 5 surgical oncologists, and all reconstructions were performed by the senior author (HYK).

Patient demographics, procedural characteristics, intraoperative tissue expander volume, and postoperative outcomes were recorded. The patient demographic data recorded included age, BMI, oncologic characteristics, indication for mastectomy, comorbid medical conditions, anticoagulant use, tobacco use, and previous breast surgery. The comorbid medical conditions included hypertension, diabetes, dyslipidemia, and peripheral artery disease. Perioperative data were also collected on chemotherapy and radiotherapy administered either before or after surgery. Pre-mastectomy measurements including ptosis grade, nipple-to–sternal notch distance, nipple-to–inframammary fold distance, and breast base width were also collected.

Postoperative data collected included length of hospital stay, antibiotics, and follow-up duration. Postoperative complications including seroma, hematoma, major infection, minor infection, skin and nipple necrosis, fat necrosis, capsular contracture, and removal of implant were defined as those occurring after the reconstruction. Patients were divided retrospectively based on intraoperative fill volume and analyzed postoperatively. Large intraoperative fill was defined as saline fill volume greater than 350 mL. The exact volume of 350 mL was chosen arbitrarily but represented the upper range of fill volume required at the authors’ institution. Major infections were defined as those requiring surgical intervention (eg, debridement and explantation) or hospitalization for intravenous antibiotics. Minor infections were defined as cellulitis or erythema that resolved with oral antibiotics and did not require hospitalization.

Statistical analysis was performed using SPSS v24 (SPSS Inc). P values were calculated from Pearson chi-square tests of independence and t tests assuming equal variance. A P value less than .05 was considered statistically significant in this study.

A total of 86 patients and 147 breasts that underwent immediate reconstruction with tissue expander placement between 2016 and 2018 were included in this study. No patients were excluded. All patients were followed after tissue expander volume placement until they received implants. The mean intraoperative fill volume delivered was 246.4 ± 106.6 mL. Of the 147 tissue expander placements reviewed, 24% (n = 35) had greater than 350 mL intraoperative fill volume. The remaining 76% (n = 112) were filled with less than 350 mL of saline intraoperatively.

Patient demographics are summarized in Table 1. The average age of patients with intraoperative fill volume greater than 350 mL (Group A) was 52.6 years versus 47.9 years for the group with fill volume less than 350 mL (Group B) (P = .044). The mean BMI of patients in Group A was significantly higher than that in Group B (33.2 vs 26.0 kg/m²; P < .0001). Group A had more patients with diabetes (14.3% vs 8.0%), hyperlipidemia (22.9% vs 17.0%), and anticoagulant use (17.1% vs 7.1%). However, the differences in these comorbidities were not statistically significant. Hypertension was more common in Group A (51.4% vs 21.4%), and smoking was more common in Group B (11.4% vs 17.0%).

In Group A, 0 (0.0%), 13 (37.1%), and 18 breasts (51.4%) had grade I, II, and III ptosis, respectively; in Group B, 12 (10.7%), 62 (55.4%), and 24 (21.4%) breasts were affected, respectively. The difference in ptosis between the 2 groups was statistically significant (P = .002). As expected, patients with high fill volume had greater preoperative anthropometric dimensions. The mean nipple-to–sternal notch distance (23.3 cm vs 28.2 cm; P < .0001), nipple-to–inframammary fold distance (8.1 cm vs 9.8 cm; P < .0001), and base width (13.2 cm vs 14.7 cm; P < .0001) was significantly greater in Group A.

Additionally, prior breast surgery was reported in 5.7% of patients in Group A and 18.8% of patients in Group B (P = .064). Preoperative chemotherapy or radiotherapy histories were similar for both groups (P = .926 and P = .839, respectively).

Procedure characteristics are shown in Table 2. Overall, 44.2% of breasts underwent prophylactic mastectomies, and mastopexy was performed in 27.9% of cases. AlloDerm Regenerative Tissue Matrix (LifeCell) was used in 98.0% of total procedures. Sentinel lymph node biopsy was performed in 42.2% of total cases. SPY-PHI (Stryker) imaging was used significantly less for patients in the large intraoperative tissue expander fill volume group (74.1% vs 48.6%; P = .005).

Postoperative outcomes are summarized in Table 3. Median follow-up across both groups was 18 months (mean, 20.1 months; range, 3-55 months). More complications were noted in the group with the large intraoperative fill volume. However, after univariate analysis, these differences were not statistically different (22.9% vs 18.8%; P = .59). The individual complication rates for fat necrosis (Group A: 14.3% vs Group B: 10.7%; P = .56), seroma (14.3% vs 5.4%; P =0.08), explantation (11.4% vs 7.1%; P = .42), major infection (11.4% vs 4.5%; P = .13), skin/nipple necrosis (8.6% vs 6.3%; P = .63), hematoma (5.7% vs 0.9%; P = .08), capsular contracture (2.9% vs 5.4%; P = .54), and minor infection (2.9% vs 5.4%; P = .54) were not statistically significant. In Group A, 7 patients required a return to the operating room for hematoma evacuation (n = 1), skin necrosis (n = 2), and explantation (n = 4). In Group B, 12 patients required reoperation for explantation (n = 8) and debridement of skin/nipple necrosis without explantation (n = 4).

After multivariate analysis, high fill volume was not found to be a significant predictor of skin or nipple necrosis (95% confidence interval [CI], 0.3-7.4; P = .62). Hypertension, however, was associated with increased skin and nipple necrosis in this cohort (95% CI, 1.1-60.8; P = .04). This association was not seen in any of the other variables analyzed, such as anticoagulant use, tobacco use, previous breast surgery, or any other comorbid medical conditions.

With the various options available for breast reconstruction for postmastectomy patients, it is imperative to understand the risks involved with each reconstructive technique to improve patient safety and optimize costs. Immediate tissue expansion for 2-stage breast reconstruction following skin- and nipple-sparing mastectomies is widely recognized as a safe, cost-effective, and reliable reconstructive option for breast cancer patients.¹⁶ It offers the advantages of rapid recovery time and lack of donor site morbidity as well as improved aesthetic outcomes.¹⁷ Together, this provides breast cancer patients additional psychosocial benefits and greater overall satisfaction.^18,19

Higher intraoperative percent fill has been identified as a risk factor for complications, prompting conservative approaches to tissue expander volumes.⁸ Sue et al described this negative effect in a cohort of 282 patients with initial tissue expander volumes around 300 mL.⁷ This paradigm, however, is not well established as other studies have demonstrated that larger intraoperative fill volume is not independently associated with increased complications.^10,14 Determining the appropriate indications for intraoperative fill volume and the corresponding risk profile is clinically important as it may guide reconstructive techniques and improve individualized risk assessment.

The current study demonstrates that a higher initial intraoperative tissue expander fill volume is not associated with greater complication rates in patients undergoing immediate breast reconstruction with tissue expander placement. The group with high intraoperative fill volume had a skin or nipple necrosis rate of 8.6%. The rate of skin and nipple necrosis in this cohort was similar to that published in the literature (4.3%-14%).^20-23 In a study involving 246 breasts and patients with a much smaller average BMI (23.9 kg/m²), necrosis remained the most common complication (4.9%) following immediate tissue expander breast reconstruction.²⁴ However, no patient in the study received more than 100 mL of saline intraoperatively, and predominantly the patients with above-average BMI developed necrosis. Thus, certain comorbidities that also appear to accompany higher initial tissue expander volume (eg, obesity) could be the underlying determinants for increased complication rates, not the volume per se.²⁵

In a retrospective study of 966 patients, Khavanin et al identified age, hypertension, and obesity as risk factors that contribute synergistically to increase the risk of necrosis with a high intraoperative expander fill volume.⁹ These findings are corroborated by several other studies determining that greater age or hypertension increases the odds of a complication occurring in breast reconstruction with tissue expanders.^12,26-32

In addition, tissue expanders may increase the tension on the overlying mastectomy skin, leading to ischemia and subsequent necrosis.^33,34 This provides a mechanistic explanation as to why some studies have identified higher percent fill as a risk factor for complications. Despite this, the current study did not find an association between high initial fill volume and rates of necrosis, nor were any other complications increased by a statistically significant difference.

Expander size is selected based on body weight, body height, chest wall width, breast contour, and resected breast mass. In the current cohort, patients with high intraoperative fill volume were found to have significantly greater anthropometric dimensions, BMI, and ptosis grade. Naturally, these characteristics call for greater percent fill and, in fact, may serve to benefit these patients. Patients generally tolerate 20% volume expansion in the initial fill, but overlying soft tissue laxity and desired final appearance may justify intraoperative filling up to 50%.²⁰

Other studies suggest an even more aggressive protocol of 75% initial fill volume, citing rapid postoperative expansion to be a safe and reliable technique that reduces the number of office injections needed in the postoperative period and also decreases delays in adjuvant therapy.^35-38 The patients with larger initial fill volume in the current cohort received a 65% intraoperative filling of the total expander size, compared with a 44% initial fill in the <350 mL volume group (Table 2). From a cosmetic perspective, this may benefit patients with higher BMI or bra sizes by increasing the volume delivered to the lower pole, thereby preventing soft tissue contraction, facilitating reconstruction of the inframammary fold, and ultimately enhancing breast ptosis.^5,6 Skin distensibility, elasticity, and hysteresis do not appear to be compromised by overexpansion.³⁹ Taken together with the apparent safety of high intraoperative fill volume in this study, these aesthetic advantages create a compelling case for refining the current surgical approach to permit larger intraoperative tissue expander saline fill volumes in immediate 2-stage breast reconstruction for the appropriate postmastectomy patients.

The authors of this study acknowledge a relatively small sample size as a limitation. Furthermore, this cohort was not matched for preoperative patient characteristics. The retrospective nature of this study did not permit randomization and therefore was not protected against the possibility of selection bias. Although all reconstructions were performed by a single plastic surgeon, technical variability in surgeons performing mastectomy could lead to differences in outcomes. Despite these limitations, this study offers a nuanced perspective regarding the outcomes of higher fill volumes in patients undergoing immediate breast reconstruction with tissue expander placement.

Larger fill volumes are often required and benefit patients with higher BMI or bra sizes. This also reduces the number of postoperative fills required. In this patient population, larger intraoperative tissue expander saline fill volume was not associated with increased postoperative complications. After careful patient selection and perfusion evaluation, larger fill volumes may be considered a safe option to improve the aesthetic outcomes in patients with high BMI.

Affiliations: ¹Department of Plastic Surgery, Loma Linda University Health, Loma Linda, CA; ²University of California, Riverside School of Medicine, Riverside, CA

Correspondence: Hahns Y Kim, MD; HahKim@llu.edu

Funding: No funding was received for this article.

Ethics: Institutional Review Board approval was obtained.

Disclosures: The authors disclose no financial or nonfinancial competing interests. None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript.