Dissolvable Surgical Clip Improves Diagnostic Imaging

A safe surgical clip could reduce postoperative complication rates and minimize problems associated with diagnostic imaging.

Developed by researchers at Kobe University (Japan), the 5-mm dissolvable surgical clip is made of a magnesium alloy that dissolves and is absorbed by the body after a certain period of time. The alloy also contains calcium and zinc to improve its microstructure, ensuring fastening ability and formability. To evaluate the safety of the clip, an implantation study was conducted in a subcutaneous mouse model. The results showed that very little gas was produced as the clip dissolved, and there was no inflammation of the surrounding tissues after 12 weeks.

As the volume of the implanted clip was reduced by almost half during that time, the researchers concluded it would likely dissolve completely within one year. Blood tests revealed that levels of magnesium and other substances in the blood were in the normal range after 12 weeks. To evaluate the functionality of the clip, it was tested in a rat model in which the biliary duct, portal vein, hepatic artery, and hepatic vein were occluded with the clip and a partial liver was removed. During a monitoring period of eight weeks, the clip functioned properly, and micro CT scanning revealed that the quality of images was not degraded.

“We will conduct further in vivo studies and a clinical study within two to three years,” said metallurgical engineer, Prof. Toshiji Mukai, PhD, of the Kobe University Graduate School of Engineering, who was involved in developing the clip. “Kobe University works toward the development of new medical devices. We will continue to promote collaboration between the graduate schools of medicine and engineering.”

Most surgical clips are made of titanium, and as many as 30 to 40 clips may be used during a single surgical procedure. The retained clips lead to diminished quality of computed tomography (CT) and magnetic resonance imaging (MRI) images around the wound area, and can potentially cause complications.

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