Dottorato in TECNOLOGIE AVANZATE IN CHIRURGIA

Titolo della tesi: Ricostruzione mammaria immediata con protesi e copertura parziale o totale con membrane biologiche: valutazione di sicurezza, tollerabilità ed efficacia

Background Breast prosthetic reconstruction plays an important role for quality of life and satisfaction of patients subjected to “conservative” mastectomies (nipple-sparing, skin-sparing or skin-reducing), and the research of new surgical techniques, materials and medical devices is currently increasing. In particular, the advent of acellular dermal (ADM) and pericardial (APM) biological meshes has made immediate breast reconstruction possible in more cases, avoiding the use of tissue expanders, improving the quality of reconstruction, and lowering the ratio of critical complications, mainly capsule contracture. On the other hand, the use of APM is still debated, due to some specific side effects related to residual immunogenic biologic material and the productive process itself; for this reason, it is necessary to increase knowledge on tissue inflammation, integration and remodeling mechanisms. Current researches led to the development of new APMs able to reduce complication rates and prosthesis-induced adverse effects as well as maintaining their benefits for breast reconstruction. Preclinical data showed good integration of a new developed mesh (Exashape®) with low complication rates, but clinical data are still missing. The aim of the study is to assess safety, tolerability and efficacy of this new APM in comparison to another biological mesh and delayed breast reconstruction. Materials and methods We performed a prospective observational study using Exashape® for the reconstruction surgery of patients subjected to mastectomy in both dual-plane and prepectoral setting, comparing it with a cohort of patients subjected to breast reconstruction using a different type of ADM with higher biologic mass (Braxon®) and with a group of patients subjected to delayed breast reconstruction with tissue expander and definitive prosthesis. The primary objective of the stydt was to evaluate the APM’s safety, comparing major and minor complication rates of the four study groups (Exashape® prepectoral, group A1, Exashape® dual plane, group A2, Braxon® prepectoral, group B, and delayed breast reconstruction, group C). Secondary objectives were evaluation of tolerability (assessed by total sierosity, operative times, drainage maintaining times) and efficacy (APM “in vivo” integration, assessed by breast ultrasound at 1, 3, 6 and 12 months after surgery, evaluating vascularization, APM width and viscoelastic properties via elastosonography). Results We performed 26 mastectomies followed by reconstruction between 2020 and 2022, for a total of 32 breast implants and 21 meshes (14 Exashape® and 7 Braxon®). With a mean follow-up of 13,7 months, we observed no major complications and only 2 minor complications in groups A1 and A2; 2 major and 2 minor complications in group B (without any cases of capsule contracture) and 3 major complications (with 2 cases of capsule contracture) and 3 minor complications in group C. Operative times were significantly lower in A1 and A2 groups compared to group B and C, as well as amount of drained fluids and time until drain removal. Finally, in our in vivo ultrasound integration study showed good and predictable integration process in a 12-month period with progressive neovascularization and balancing of viscoelastic properties with superficial tissues, without the development of excessive fibrosis (periprosthetic capsule). Conclusion Despite the limited number of patients, our data suggested that breast prosthetic reconstruction with Exashape® APM is a valuable and safe alternative in selected patients, both in the dual plane and the prepectoral settings. Moreover, our clinical and ultrasonographic data could be the base for future studies, leading to a better understanding of biological mesh remodeling and integration process, since the balance of degradation and rebuilding process (inflammation/integration) is the key point in the clinical use of these materials.