A high-performance degradable Mg alloy suturing staple for single-arm oral stapling robot

Abstract

Minimally invasive surgery (MIS) robots, such as single-arm stapling robots, are key to oral and maxillofacial surgery because they overcome space constraints in the oral cavity and deep throat. However, biodegradable suture staples should be developed for the single-arm stapling robots to avoid a secondary operation. For this aim, a new type of Mg-3Zn-0.2Ca-2Ag biodegradable alloy wire was developed in this study applied as suture staples. Its tensile strength, yield strength, and elongation are 326.1 MPa, 314.5 MPa, and 19.6%, respectively. Especially, the alloy wire attains the highest yield strength value reported among all the biodegradable Mg wires, which is mainly attributed to fine grain strengthening and second phase strengthening such as Mg₂Zn₁₁ nano phase strengthening. Moreover, the corrosion rate of this alloy wire in simulated body fluid (SBF) reaches 26.8 mm/y, the highest value among all the biodegradable Mg alloy wires reported so far, which is mainly from the intensified galvanic corrosion between the Ag₁₇Mg₅₄ phase and the Mg matrix. In vitro studies demonstrate that the alloy wire exhibits good blood compatibility and low cytotoxicity. The cone beam computed tomography (CBCT) data shows that the suture staple made of the Mg alloy wire provides better mechanical support in the early postoperative period. From the single arm robot tests, it confirms that suture staples can close the wound tightly and remain stable over time. This research provides a good material selection for the automated suturing in oral and throat surgery robots.