Retracting Soft Tissue in Minimally Invasive Hip Arthroplasty Using a Robotic Arm

Background. All surgical procedures in orthopedics involve the retraction of soft tissue. In this study, the performance of 3 assistants holding the medial retractor during minimally invasive hip arthroplasty was compared with a semiactive retractor holder in a cadaver setup. Methods. A total of 40 measurements on 3 cadavers were carried out with each subject (3 human, 1 robot) measuring each cadaver 10 times. The retractor was equipped with a sensor array on both sides, to measure variations of the retracting pressures over a 2-minute interval. Results. The semiactive retractor holder showed an almost constant performance compared with the test subjects. There was no significant reduction of the applied pressure and almost no variation during the 2-minute interval and across all measurements. Conclusions. The performance of the semiactive retractor holder was more stable than that of a human assistant, making it suitable for intraoperative usage.