Retracting Soft Tissue in Minimally Invasive Hip Arthroplasty Using a Robotic Arm: A Comparison Between a Semiactive Retractor Holder and Human Assistants in a Cadaver Study.

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.