Can Armrests Improve Comfort and Task Performance in Laparoscopic Surgery

Compared with open surgery, laparoscopic surgery presents manipulation difficulties because the instruments are less effective, uncomfortable, and offer reduced freedom of movement.1–4 The largely static posture required during minimal access surgery, which is dictated by port placement and the site of the monitor, is known to cause eye strain and arm, shoulder, and spine discomfort.9,10 In addition, maneuvering instruments, which pass through access ports into the abdomen, increase muscle activity and require adoption of awkward positions of the upper limbs.11,12 As a result of these constraints, the physical workload in laparoscopic surgery is significantly increased over that required for an equivalent open procedure.9,13 Research comparing tonic skin conductance level and electro-oculograms in both conventional and endoscopic tasks has demonstrated that most surgeons experience greater mental effort, frustration, and tension during laparoscopy than during open surgery.5 Indeed, a “surgical fatigue syndrome,” which occurs on average after 4 hours of laparoscopic surgery, has been described.14 Its symptoms include mental exhaustion, increased irritability, impaired surgical judgment, and reduced dexterity. Efforts to improve the ergonomics of laparoscopic surgery, and consequently reduce the error rate, have enabled the ideal position of the laparoscopic surgeon to be defined: the arms should be slightly abducted, pronated, and rotated inward at shoulder level; the elbows should be bent at 90° to 120° and the instruments should be grasped while maintaining the natural position of an inactive hand.15 Unfortunately, this position is frequently in conflict with constraints imposed by the operating environment, and the surgeon is often obliged to maintain an awkward stance with both arms abducted. The use of an arm support has been investigated in other fields of manual manipulation requiring prolonged and constrained posture, unsupported arms, direction-fixed gaze, and the need for execution of precise movements. In video display terminal workers, muscular fatigue and discomfort were increased when an arm support was not used.16–18 Conversely, the use of an armrest has been shown to reduce the load on the shoulder muscles.19 In the medical field, armrests have been designed for ocular microsurgery and neurosurgery.20,21 Previous basic ergonomic studies22 indicated that support of the shoulder, elbow, and wrist significantly improves the accuracy of laparoscopic manipulations by the endoscopic surgeon, demonstrating the need for intuitive forearm/hand rests in laparoscopic surgery. The aim of the present study was to evaluate the effect of an armrest on laparoscopic task performance and surgeons' comfort. For precise quantification, the experiments were carried out using a virtual reality laparoscopic surgical simulator. The experiments were designed to test the hypothesis that the provision of an ergonomic armrest facilitates greater manipulative control and accuracy, hence reducing error rate and discomfort level experienced by the surgeon during simulated laparoscopic surgery.