Nancy E. Quick

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.

Acute effects of the Protonics system on patellofemoral alignment: an MRI study

This study used magnetic resonance imaging (MRI) to determine whether changes in patellofemoral alignment occur after initial treatment with the Protonics exercise device. The first scan was obtained before the device was used. After performing a set of exercises with no resistance on the device the device was removed, and a second scan was obtained. The same set of exercises was again performed with resistance on the device set at the appropriate level, and a final scan was obtained with the device removed. An isometric leg press was maintained as each image was obtained to simulate more closely a functional weight-bearing activity. Subjects were 26 women with complaints of patellofemoral pain. The main outcome measures were: patellar tilt angle, bisect offset, and lateral facet angle. Nonparametric repeated measures analysis of variance tests showed no differences between test conditions for any of the three measures of patellofemoral alignment. We conclude that after an initial treatment session using the Protonics system there is no change in patellofemoral alignment as determined by MRI.

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.

Laparoscopic Dissecting Instruments

The authors provide an overview of laparoscopic dissecting instruments and discuss early development, surgical options, and special features. End effectors of different shapes and functions are described. A comparison of available energy sources for laparoscopic instruments includes discussion of thermal dissection, ultrasonic dissection, and water-jet dissection. The ergonomic risks and challenges inherent in the use of current laparoscopic instruments are outlined, as well as ergonomic issues for the design of future instruments. New directions that laparoscopic instrumentation may take are considered in connection with developing technology in robotics, haptic feedback, and MicroElectroMechanical Systems. Copyright

The effect of a single treatment of the Protonics™ system on biceps femoris and gluteus medius activation during gait and the lateral step up exercise

INTRODUCTION Patellofemoral pain, a frequent complaint among women, is attributed in part to excessive femoral internal rotation, leading to patellofemoral malalignment. The Protonics resistive dynamic knee orthosis was designed to facilitate hamstring activation, leading to a less anteriorly tilted pelvis and less femoral internal rotation. This decrease in femoral internal rotation is thought to improve patellofemoral joint alignment, thereby reducing knee pain. In this position, the gluteus medius (GM) would be more effective against the force of gravity. Therefore, this studys purpose was to determine the effects of a single application of the Protonics orthosis on knee pain and biceps femoris (BF) and GM activation. METHODS 21 females (23.4+/-3.1 years, 1.66+/-0.05 m, 65.3+/-20.4 kg) with a history of chronic PFP participated in the study. Data were collected during level walking and a lateral-step up exercise in three conditions: pre-treatment (PRE), a placebo condition collected after the orthosis was set at zero resistance (PLAC), and post-treatment (POST). PLAC and POST were performed after the orthosis had been removed from the subjects leg. Percent of gait cycle activated, integrated EMG (IEMG), and level of pain (VAS scale) were measured in each condition. An ANOVA was used to determine significance between conditions (alpha=0.05). RESULTS Use of the Protonics orthosis did not result in any change in the level of knee pain, IEMG or duration of activation for the BF or GM. SUMMARY Our results do not support an increase in hamstring activation or decrease in GM activation following a single treatment with the Protonics orthosis.