Novel biodegradable magnesium alloy clips compared with titanium clips for hepatectomy in a rat model

The use of surgical metal clips is crucial for ligating vessels in various operations. The currently available metal clips have several drawbacks; they are permanent and interfere with imaging techniques such as computed tomography (CT) or magnetic resonance (MR) imaging and carry the potential risk of endo-clip migration. We recently developed a novel magnesium (Mg) alloy for biodegradable clips that reduces artifacts on CT imaging. This study aimed to examine the tolerance, biodegradability, and biocompatibility of the Mg alloy clips compared with those of standard titanium (Ti) clips in hepatectomy.

Thirty Wistar rats were divided into two groups based on the clip used (groups A and B). The vascular pedicle, including hepatic artery, portal vein, bile duct, and hepatic vein of the left lateral lobe, was ligated with the Ti clip in group A or the Mg alloy clip in group B, and then the left lateral lobe was removed. The rats were sacrificed at 1, 4, 12, 24, and 36 weeks after surgery. Clinical and histological evaluations were performed. Absorption rate was calculated by measuring the clip volume.

Although the Mg alloy clips showed biodegradability over time, there were no significant differences in the serum concentration of Mg between the two groups. The remaining volume ratio of Mg alloy clips was 95.5, 94.3, 80.0, 36.2, and 16.7% at 1, 4, 12, 24, and 36 weeks, respectively. No side effects occurred. Most of the microscopic changes were similar in both groups.

The new biodegradable Mg alloy clips are safe and feasible in vessel ligation for hepatectomy in a rat model and reduce artifacts in CT imaging compared with the standard Ti clips.