Atraumatic metamaterial-inspired inserts for surgical instruments: combined histological and finite element analysis of vascular tissue compression

Abstract The purpose of this pilot study was to evaluate how material compliance, surface geometry and internal architecture of atraumatic clamping inserts influence vascular tissue injury. The main research question was whether metamaterial-inspired inserts can reduce vessel trauma during compression. Inserts were fabricated using additive manufacturing from two medical grade elastomers with different stiffness levels. All samples had identical external dimensions but differed in surface geometry – either smooth or grooved – and in internal architecture, including solid cores and channel-based structures. Porcine aorta specimens were compressed under controlled physiological conditions for a clinically relevant duration. Tissue damage was assessed qualitatively using histological analysis and graded according to a standardized injury scale. Surface topography was examined using digital microscopy. Experimental findings were supported by nonlinear numerical simulations of vessel compression to evaluate stress and strain distributions. Inserts manufactured from the more compliant elastomer generally produced lower grades of vascular injury than stiffer inserts. In the BioMed 80A group, deeply structured surface variants were generally associated with increased tissue damage. Numerical simulations supported the experimental findings, suggesting that contact surface geometry was the primary factor influencing stress concentrations in the vessel wall, with material stiffness playing a secondary role. The results suggest that atraumatic performance of metamaterial-inspired clamping inserts appears to be influenced by the combined effects of surface geometry, internal architecture and material compliance. Compliant metamaterial-inspired inserts with optimized internal channel structures show promise for minimizing vascular tissue trauma during surgical procedures. However, these preliminary findings require further quantitative validation in larger studies.