Long-Term Maintenance of Projection of Nipples Reconstructed Using Three-Dimensionally Printed Poly-4-Hydroxybutyrate Bioabsorbable Scaffolds

Abstract

Background: For patients who are unable to undergo nipple-sparing mastectomy, reconstruction of the nipple-areola complex has been shown to promote greater satisfaction in cosmetic outcome, body image, and sexual relationships. Although a variety of techniques have been developed to optimize the shape, size, and mechanical properties of the reconstructed nipple-areola complex, maintenance of sustained nipple projection over time remains a challenge for plastic surgeons. Methods: Three-dimensionally printed poly-4-hydroxybutyrate (P4HB) scaffolds were designed and fabricated filled with either mechanically minced or zested patient-derived costal cartilage, designed with an internal P4HB lattice (rebar) to provide interior structure to foster tissue ingrowth, or left unfilled. All scaffolds were wrapped within a C-V flap on the dorsa of a nude rat. Results: One year after implantation, neonipple projection and diameter were well preserved in all scaffolded groups compared with nonscaffolded neonipples (P < 0.05). Histologic analysis showed significant vascularized connective tissue ingrowth at 12 months in both empty and rebar-scaffolded neonipples and fibrovascular cartilaginous tissue formation in mechanically processed costal cartilage–filled neonipples. The internal lattice promoted more rapid tissue infiltration and scaffold degradation and best mimicked the elastic modulus of the native human nipple after 1 year in vivo. No scaffolds extruded or caused any mechanical complications. Conclusions: Three-dimensionally printed biodegradable P4HB scaffolds maintain diameter and projection while approximating the histologic appearance and mechanical properties of native human nipples after 1 year with a minimal complication profile. These long-term preclinical data suggest that P4HB scaffolds may be readily translated for clinical application. Clinical Relevance Statement: The authors’ unique, three-dimensionally printed P4HB scaffolds can be used to create custom nipple scaffolds that contour to any nipple shape and size, enabling the fabrication of tissue-engineered neonipples with significantly greater projection maintenance and closely approximating desired nipple biomechanical properties.