Changes in postural mechanics associated with different types of minimally invasive surgical training exercises.

BACKGROUND: Doctors who perform minimally invasive surgery commonly report upper extremity fatigue or joint and muscle pain. The goal of this study was to investigate the changes in postural parameters associated with different laparoscopic training tasks and graspers. METHODS: Three different training tasks (targeted object release, rope passing, and cable tying) were performed with three types of laparoscopic graspers. Joint angles were determined using video analysis, and centers of pressure (COP) were measured with force platforms. RESULTS: Cable tying proved to be the most challenging training task and involved greater joint angle excursions and COP excursions and velocities. Grasper 2 reduced shoulder and wrist flexion-extension over the selected tasks. CONCLUSION: Training tasks should be designed to simulate surgical procedures because different tasks require distinct combinations of joint rotations. Joint rotations and postural balance should be considered when an optimal grasper is selected for a particular training task.

The effect of using laparoscopic instruments on muscle activation patterns during minimally invasive surgical training procedures.

BACKGROUND: Many surgeons report pain as a result of muscle fatigue during laparoscopy. Therefore, determining how surgical task or instrument selection influences the duration of muscle activation may provide insight into the relationship between laparoscopic instrumentation and muscle fatigue. METHODS: Surface electromyography (EMG) electrodes were placed over the right deltoid, trapezius, bicep, pronator teres, flexor carpi ulnaris, and extensor digitorum superficialis muscles of four surgeons. These surgeons were then asked to perform a targeted grasp and release (T1), a simulated bowel inspection (T2), and a cable-tying exercise (T3) while using three different inline finger-looped graspers. The graspers included a nonratcheted handle with a single-action blunt-end effector (G1) and two models that had ratcheted handles with dual-action end effectors (G2, G3). Resting and maximal voluntary contraction EMG values for each muscle were used to normalize the data and to determine percentage of activation during each task. A multivariate analysis of variance (ANOVA) was used to compare EMG relative time of activation (RAT) patterns with grasper, task, and grasper and task interaction. RESULTS: In general, when grasper and task were considered individually, G1 and T3 demonstrated the highest RAT. Findings showed that RAT was most affected by the use of either G1 or G2 during T2 or T3. CONCLUSION: Task, grasper, and the interaction between grasper and task all appear to influence the RAT and therefore, to varying degrees, all three may play a role in influencing muscle fatigue.