Ergonomic Assessment of Surgeon Characteristics and Laparoscopic Device Strain in Gynecologic Surgery.

STUDY OBJECTIVE: To evaluate whether surgeon characteristics, including sex and hand size, were associated with grip strength decline with laparoscopic advanced energy devices. DESIGN: Prospective cohort study. SETTING: Ergonomic simulation at an academic tertiary care site and the Society of Gynecologic Surgeons 47th Annual Meeting. PATIENTS: Thirty-eight participants (19 women and 19 men) were recruited. INTERVENTIONS: Surgeon anthropometric measurements were collected. Each participant completed a 120-second trial of maximum voluntary effort with 3 laparoscopic advanced energy devices (LigaSure, HALO PKS, and ENSEAL). Grip strength was measured using a handheld dynamometer. Subjects completed the NASA Raw Task Load Index scale after each device trial. Grip strengths and ergonomic workload scores were compared using Student t tests and Wilcoxon rank sum tests where appropriate. Univariate and multivariate models analyzed hand size and ergonomic workload. MEASUREMENTS AND MAIN RESULTS: Women had lower baseline grip strength (288 vs 451 N) than men, as did participants with glove size <7 compared with ≥7 (231 vs 397 N). Normalized grip strength was not associated with surgeon sex (p = .08), whereas it was significantly associated with surgeon glove size (p <.01). Grip strength decline was significantly greater for smaller compared to larger handed surgeons for LigaSure (p = .02) and HALO PKS devices (p <.01). The ergonomic workload of device use was significantly greater for smaller compared to larger handed surgeons (p <.01). Surgeon handspan significantly predicted grip strength decline with device use, even after accounting for potential confounders (R2 = .23, ß = .8, p <.01). CONCLUSION: Surgeons with smaller hand size experienced a greater grip strength decline and greater ergonomic workload during repetitive laparoscopic device use. No relationship was found between surgeon sex and grip strength decline or ergonomic workload. Laparoscopic device type was also identified as a significant main effect contributing to grip strength decline. These findings point toward ergonomic strain stemming from an improper fit between the laparoscopic device and the surgeon's hand during device use.

Location of brachial plexus birth injury affects functional outcomes in a rat model.

Brachial plexus birth injury (BPBI) results in shoulder and elbow paralysis with shoulder internal rotation and elbow flexion contracture as frequent sequelae. The purpose of this study was to develop a technique for measuring functional movement and examine the effect of brachial plexus injury location (preganglionic and postganglionic) on functional movement outcomes in a rat model of BPBI, which we achieved through integration of gait analysis with musculoskeletal modeling and simulation. Eight weeks following unilateral brachial plexus injury, sagittal plane shoulder and elbow angles were extracted from gait recordings of young rats (n = 18), after which rats were sacrificed for bilateral muscle architecture measurements. Musculoskeletal models reflecting animal-specific muscle architecture parameters were used to simulate gait and extract muscle fiber lengths. The preganglionic neurectomy group spent significantly less (p = 0.00116) time in stance and walked with significantly less (p < 0.05) elbow flexion and shoulder protraction in the affected limb than postganglionic neurectomy or control groups. Linear regression revealed no significant linear relationship between passive shoulder external rotation and functional shoulder protraction range of motion. Despite significant restriction in longitudinal muscle growth, normalized functional fiber excursions did not differ significantly between groups. In fact, when superimposed on a normalized force-length curve, neurectomy-impaired muscle fibers (except subscapularis) accessed regions of the curve that overlapped with the control group. Our results suggest the presence of compensatory motor control strategies during locomotion following BPBI. The clinical implications of our findings support emphasis on functional movement analysis in treatment of BPBI, as functional and passive outcomes may differ substantially.