Postural Comparison of Minimally Invasive and Open Surgery on a Cadaveric Porcine Model
Abstracts
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Motion constraints introduced by minimally invasive surgery (MIS) instrumentation may put the surgeon at an increased risk of fatigue, muscular and joint pain, and neuropathies over conventional open surgery. The purpose of this study was to compare the differences in postural and kinematic parameters between MIS and open surgery using a cadaveric porcine model. Another goal of this study was to identify ergonomic indicators that might be of value when evaluating new and existing designs of laparoscopic instruments. Two surgeons performed 22 bowel inspection procedures alternatively using open surgery technique and a MIS approach using a ratcheted grasper with a double-action blunt end effector. During the trials, the surgeons stood on force platforms to monitor centers of pressure (COP) and wore a set of 43 reflective markers to track segmental kinematics. COP and joint angle excursions were calculated by subtracting the maximum and minimum values that occurred during the trial. During open surgery, the average anterior/posterior (A/P) COP was significantly greater (p < 0.001) than during MIS (23.0 cm vs. 16.4 cm), indicating that the body weight was centered further forward. However, MIS required increased amounts of weight shifting as evidenced by significantly greater COP excursions (p = 0.008 and p < 0.001) in both the A/P (6.7 cm vs. 4.1 cm) and medial/lateral (13.6 cm vs. 4.9 cm) directions. MIS also resulted in significantly greater (p = 0.015 and p = 0.014) joint angle excursions for both radial pronation/supination (67 degrees vs. 42 degrees) and wrist flexion/extension (96 degrees vs. 68 degrees). Therefore, kinematic differences between MIS and open surgery were most prominent in movement at the forearm and wrist. In addition, the measurement of COP using force platforms appeared to be related to task difficulty and could be an option for measurement of ergonomic indicators in a surgical environment where video markers may not be an option. |
