Outcomes Of Implant-based Reconstruction Research Articles

40. Understanding Periprosthetic Capsule Pathology in Pre-pectoral Versus Sub-pectoral Implant-based Breast Reconstruction: Development of a Rat Model

PURPOSE: Clinical practices in implant-based breast reconstruction continue to evolve with ongoing innovation in both the surgical approach and implant design. Development of standardized models is increasingly important to evaluate the effect of these changes in the outcomes of implant-based reconstruction. In this study, we designed a physiological rat breast implant model to assess the effects of pre-pectoral and sub-pectoral implant placement on breast implant capsule formation. METHODS: Miniature silicone implants measuring 2cc in diameter were optimized for placement in the pre-pectoral and sub-pectoral planes bilaterally in Lewis rats for an internally controlled model. A submammary approach was simulated in rats by making skin incisions at the inferior aspect of the pectoralis muscle bilaterally. For sub-pectoral implant placement the lateral edge of the pectoralis muscle was elevated, a sub-pectoral plane was established with blunt dissection, and a sterile implant was secured in the sub-pectoral plane with complete pectoralis coverage. For pre-pectoral implant placement, blunt dissection was used on the contralateral side to establish a subcutaneous plane. A sterile implant was secured in this subcutaneous pocket. Samples were harvested at 12 weeks and histological analysis of capsule formation was performed with H&E and Trichrome staining. RESULTS: The rats showed immediate signs of bilateral forelimb use with walking and grasp following recovery from anesthesia. The surgical sites healed well over two-week follow-up with no signs of wound-site mutilation, discomfort, or dehiscence. Histological analysis demonstrated both pre-pectoral and sub-pectoral capsule formation compared to sham surgery samples. Prepectoral implant capsules showed lamellar collagen architecture whereas subpectoral implant capsules demonstrated increased thickness, hypercellularity and synovial metaplasia. CONCLUSIONS: This model demonstrates that a physiological approach with pre-pectoral and sub-pectoral implant placement to model breast implant reconstruction is feasible in rats and thus improves upon previous models that utilize dorsal subcutaneous pockets instead of pectoral planes. These earlier approaches do not replicate the anatomy and mechanics of the clinical prepectoral and subpectoral space. Additionally, this model demonstrates differences in the periprosthetic fibrotic processes in pre-pectoral and sub-pectoral approaches for implant placement. This model facilitates further mechanistic understanding of the physiology and pathology associated with breast implant reconstruction including outcomes such as capsular contracture and BIA-ALCL and will provide a valuable platform to test treatments and strategies that may mitigate them.

Abstract: Implant-Based Breast Reconstruction and the Timing of Adjuvant Radiotherapy: A Systematic Review and Meta-Analysis of Surgical Outcomes

INTRODUCTION: Implant-based breast reconstruction is the most common type of reconstruction following post-mastectomy radiation therapy (PMRT). The impact of the timing of PMRT to a tissue expander or permanent implant is not well understood. The purpose of this systematic review was to evaluate outcomes in implant-based reconstruction and the timing of PMRT. METHODS: A review of the English literature in the PubMed/MEDLINE database (2000–2016) was performed to identify all manuscripts on implant-based breast reconstruction and PMRT. Cases from each study were grouped by PMRT to a tissue expander or PMRT to a permanent implant. Outcomes of interest included reconstructive failure and capsular contracture as overall rates and associations were pooled. Effect sizes (z-values), risk ratios (RRs), and heterogeneity scores (I2) were calculated on meta-analysis. RESULTS: There were 20 studies meeting inclusion criteria with 2,348 patients identified. Pooled analysis revealed an overall rate of reconstructive failure of 17.6% and Baker grade III / IV capsular contracture of 37.5%. PMRT applied to tissue expanders resulted in higher rates of reconstructive failure compared to PMRT applied to permanent silicone implants (20% vs. 13.4%, RR = 2.33, p = 0.0083, 95% CI 1.24 – 4.35), but lower rates of capsular contracture (24.5% vs. 49.4%, RR = 0.53, p = 0.083, 95% CI 0.26 – 1.09). CONCLUSION: Regardless of timing, PMRT applied to implant-based breast reconstruction was associated with high risk of reconstructive failure and capsular contracture. Surgeons should consider alternative strategies, such as autologous tissue reconstructions, in patients requiring PMRT.

Evidence-Based Medicine: Alloplastic Breast Reconstruction.

After studying this article, the participant should be able to: 1. Understand the different advances that have resulted in improved outcomes in implant-based reconstruction. 2. Gain knowledge about specific techniques that have evolved rapidly in recent years and how to implement these. 3. Gain an understanding of controversies associated with alloplastic reconstruction. 4. Recognize undesirable outcomes in implant-based breast reconstruction and understand strategies for correction. There have been multiple advances in implant-based breast reconstruction. Many of these have resulted in improvements in patient outcomes and care. Understanding new techniques and technologies ensures competence in providing care for the alloplastic breast reconstruction patient. This article was prepared to accompany practice-based assessment with ongoing surgical education for the Maintenance of Certification for the American Board of Plastic Surgery. It is structured to outline the care of the patient with the postmastectomy breast deformity.

A meta-analysis of implant-based breast reconstruction and timing of adjuvant radiation therapy

BackgroundImplant-based breast reconstruction is the most common type of reconstruction after postmastectomy radiation therapy (PMRT). The impact of the timing of PMRT to a tissue expander or permanent implant is not well understood. The purpose of this systematic review was to evaluate outcomes in implant-based reconstruction and the timing of PMRT. MethodsA review of the English literature in the PubMed/MEDLINE database (2000-2016) was performed to identify all articles on implant-based breast reconstruction and PMRT. Cases from each study were grouped by PMRT to a tissue expander or PMRT to a permanent implant. Outcomes of interest included reconstructive failure and capsular contracture as overall rates and associations were pooled. Effect sizes (z values), risk ratios (RRs), and heterogeneity scores (I2) were calculated on meta-analysis. ResultsThere were 20 studies meeting inclusion criteria with 2348 patients identified. Pooled analysis revealed an overall rate of reconstructive failure of 17.6% and Baker grade III/IV capsular contracture of 37.5%. PMRT applied to tissue expanders resulted in higher rates of reconstructive failure compared with PMRT applied to permanent silicone implants (20% versus 13.4%, RR = 2.33, P = 0.0083, 95% confidence interval 1.24-4.35), but lower rates of capsular contracture (24.5% versus 49.4%, RR = 0.53, P = 0.083, 95% confidence interval 0.26-1.09). ConclusionsRegardless of timing, PMRT applied to implant-based breast reconstruction was associated with high risk of reconstructive failure and capsular contracture. Surgeons should consider alternative strategies, such as autologous tissue reconstructions, in patients requiring PMRT.