L’INTEGRAZIONE DELLE MATRICI DI COLLAGENE IN CHIRURGIA RICOSTRUTTIVA: STUDIO SPERIMENTALE E APPLICAZIONI CLINICHE

The use of acellular matrices (ADMs) has become a clinical reality in many fields of plastic surgery, especially in breast and abdominal reconstruction. The goal is to induce soft-tissues regeneration rather than “simple” reconstruction. However many aspects of scaffold-host crosstalking are poorly understood and the clinical experience has not often a strong experimental background. Few data exist evaluating the time and the modality of ADMs integration in host’s tissues; thus we analyzed the repopulation kinetics of a porcine derived dermal scaffold in an incisional hernia rat model, in order to shed light on the biological basis of ADM integration. An experimental study was conducted using an established rat model of ventral hernia repair. Fascial hernia defects were repaired in a tension-free manner with a 2,5x2,5 cm patch of a porcine-derived ADM in the sublay bridging position. Macroscopically and histological analysis showed ADM progressive integration in host’s tissues. In summary, the scaffold is still present and recognizable after 8 weeks, when complete integration has not still occurred. The inflammatory response, which we believe fundamental for ADM repopulation has a peak after two weeks, and gradually extinguishes in many months. Neo-angiogenesis begins in the second week, together with peri-prosthetic capsule formation. Collagen remodelling continues after many months, with differences between the sub- muscular portion and the bridging part. Moreover, an experimental study of breast reconstruction (with AMD surrounding a silicone implant) was conducted. 1x1 cm squares of a silicone sheet were placed subcutaneously on the back of the 8 rats. On the right side, silicone sheet will be covered by a scaffold (Braxon) clinically utilized in breast reconstruction to close the submuscular pocket. On the left side (internal controls), the silicone sheets will be placed without ADM. Preliminary results seems to suggest a lower rate of capsular contraction with ADM. Finally we report our experience with ADM in clinical practice, analyzing the rate of complications and clinical outcome in patient who underwent abdominal and breast reconstruction with collagen matrices. In conclusion, our study demonstrates that the scaffold integration is not complete after many months, thus post- operative recommendations and follow-up should be modified accordingly. The knowledge of the biological responses behind scaffolds repopulation should ameliorate the ability of physicians to make data-driven recommendations on clinical indications, surgical techniques and outcomes following ADM-assisted soft tissues reconstruction.