Mechanical fabrication and evaluation of bioresorbable barbed sutures with different barb geometries

Bioresorbable polymeric sutures are gaining interest from surgeons and patients as they reduce surgical stress and trauma. This study involves two bioresorbable polymers, namely, catgut and poly(4-hyrdorxybutyrate) (P4HB) that are used widely in cosmetic procedures. P4HB barbed sutures are favorably used in rhytidectomy (micro-facelifts) procedures while catgut sutures are widely used for external wound closure after surgical interventions. This study involves the mechanical fabrication of catgut and P4HB barbed sutures and compares their mechanical and anchoring properties. Barbed sutures were fabricated with two different barb geometries namely, straight and curved barbs. The mechanical properties were evaluated via tensile testing, and the anchoring performance was studied by means of a suture-tissue pull-out protocol using porcine dermis tissue which was harvested from the medial dorsal site. The fabricated barbed sutures of both materials showed a similar trend compared to non-barbed sutures of decreases in failure stress, strain at failure, and work to rupture or toughness which was reduced by about 70%. At the same time there was a 15% increase in the initial modulus or stiffness of the barbed sutures. The pull-out force for the barbed sutures with straight barbs was similar for both P4HB (5.04±0.8N) and catgut (4.47±3.8N), and as expected, were higher than that of non-barbed sutures of the same size. It was also observed that barbed sutures with curved barbs also required a higher pull-out force than those sutures with straight barbs. It was concluded that by barbing sutures with different barb shapes and geometries, a range of barbed suture products could be fabricated, each meeting the closure requirements for different types of tissue and therefore being suitable for different surgical procedures.