Abstract 159: Deformity After Prepectoral Versus Subpectoral Implant-based Breast Reconstruction: A Clinical Outcomes And Differential Costs Analysis

Abstract

Purpose: Prepectoral implant-based breast reconstruction after mastectomy has regained popularity over subpectoral implant placement in recent years. With the advent of novel tissue replacement matrices and tissue perfusion assessment technologies, prepectoral implant placement has been shown to confer multiple advantages over subpectoral placement, such as reduced animation deformity, decreased pain, and improved muscular function. However, prepectoral implant placement does carry certain disadvantages such as contour deformity and rippling. This study evaluated deformity and revision surgery after prepectoral versus subpectoral breast reconstruction in post-mastectomy patients. Methods: This was an Institutional Review Board-approved retrospective analysis of mastectomy patients undergoing implant-based reconstruction at our institution between October 2016 and July 2019. Medical records were reviewed for patients’ clinical/demographic characteristics, surgeries, outcomes/revisions, and surgical charges. Two-tailed chi square tests and Student’s t test analyses were used where appropriate to compare prepectoral and subpectoral implant groups. Hierarchical multivariate regression was used to generate crude and adjusted odds ratios and 95 percent confidence intervals for outcomes data. The two-tailed threshold for statistical significance was set at p values < 0.05. Results: One-hundred-eighty patients (296 breasts) met inclusion criteria during the study period, of whom, 76 (42.2%) received prepectoral implants and 104 (57.8%) received subpectoral implants. Mean follow-up was 212 days for patients with prepectoral implants and 203 days for subpectoral implants. After adjusting for clinical and demographic factors, a significantly-greater proportion of prepectoral implants developed skin rippling/wrinkling when compared to subpectorally-placed implants (46.5% versus 10.4%, p<0.0001). Similarly, prepectorally-placed implants demonstrated significantly-higher rates of superior pole contour deformity (59.4% versus 38.0%, p=0.02) than subpectoral implants. However, adjusted capsular contracture rates were similar between prepectoral and subpectoral implant cohorts. A significantly-greater proportion of patients with prepectoral implants received fat grafting upon initial implant placement (75.4% versus 37.8%, p<0.0001) as well as revision fat grafting (78.3% versus 42.17%, p=0.03). The mean number of revision surgeries for prepectoral implants was 1.4 (standard deviation: 0.8), which was significantly greater than the mean number of revision surgeries for subpectoral implants was 0.9 (standard deviation: 0.5; p=0.001). Total revision surgery(ies) costs were greater in patients with prepectoral implants than those with subpectoral implants, though this difference reached borderline significance ($3154 versus $1636 respectively, p=0.05). Lastly, upon multivariate hierarchical regression of individual breasts adjusting for anatomic placement of the implant (prepectoral versus subpectoral), lower body mass index independently predicted prepectoral implant contour deformity/rippling (odds ratio: 1.5, 95% confidence interval 1.2-1.8, p=0.02). Conclusion: In our cohort, prepectoral implants were associated with greater postoperative rippling/contour deformity and revision costs than subpectoral implants. Such information could help inform decision-making regarding breast reconstruction, when weighed against previous data demonstrating improved quality of life/decreased pain and narcotic-use following prepectoral placement. Further study is required to comprehensively evaluate cost-effectiveness of prepectoral versus subpectoral implant-based reconstruction, taking into consideration both long-term quality of life and costs.