A multifactorial evaluation of objective performance indicators and video analysis in the context of case complexity and clinical outcomes in robotic-assisted cholecystectomy.

BACKGROUND: The increased digitization in robotic surgical procedures today enables surgeons to quantify their movements through data captured directly from the robotic system. These calculations, called objective performance indicators (OPIs), offer unprecedented detail into surgical performance. In this study, we link case- and surgical step-specific OPIs to case complexity, surgical experience and console utilization, and post-operative clinical complications across 87 robotic cholecystectomy (RC) cases. METHODS: Videos of RCs performed by a principal surgeon with and without fellows were segmented into eight surgical steps and linked to patients' clinical data. Data for OPI calculations were extracted from an Intuitive Data Recorder and the da Vinci ® robotic system. RC cases were each assigned a Nassar and Parkland Grading score and categorized as standard or complex. OPIs were compared across complexity groups, console attributions, and post-surgical complication severities to determine objective relationships across variables. RESULTS: Across cases, differences in camera control and head positioning metrics of the principal surgeon were observed when comparing standard and complex cases. Further, OPI differences across the principal surgeon and the fellow(s) were observed in standard cases and include differences in arm swapping, camera control, and clutching behaviors. Monopolar coagulation energy usage differences were also observed. Select surgical step duration differences were observed across complexities and console attributions, and additional surgical task analyses determine the adhesion removal and liver bed hemostasis steps to be the most impactful steps for case complexity and post-surgical complications, respectively. CONCLUSION: This is the first study to establish the association between OPIs, case complexities, and clinical complications in RC. We identified OPI differences in intra-operative behaviors and post-surgical complications dependent on surgeon expertise and case complexity, opening the door for more standardized assessments of teaching cases, surgical behaviors and case complexities.

Restraint systems considering occupant diversity and pre-crash posture.

OBJECTIVE: Use volunteer data and parametric finite element (FE) human body models to investigate how restraint systems can be designed to adapt to a diverse population and pre-crash posture changes induced by active safety features. METHODS: Four FE human models were generated by morphing the midsize male GHBMC simplified model into geometries representing a midsize male, midsize female, short obese female (BMI 40 kg/m2), and large obese male (BMI 40 kg/m2) based on statistical skeleton and body shape geometry models. Each human model was positioned in a generic vehicle driver environment using two occupant pre-crash postures based on volunteer test results including one resulting from 1-g abrupt braking events. Improved restraint designs were manually developed for each occupant model in a 56 km/h frontal crash condition by adding a knee airbag, adjusting the shoulder belt load limit, steering column force, and driver airbag properties (tethers, inflation, and vent size). The improved designs were then tested at both pre-crash postures. Injury risks for the head, neck, chest, and lower extremities were analyzed. RESULTS: Human size and shape dominated the occupant injury measures, while the pre-crash-braking induced posture had minimal effects. Some of the safety concerns observed for large occupants include head strike-through the airbag and a conflict between head and chest injuries, which were mitigated by a stiffer restraint system with properly-tuned driver airbag. Chest injuries were a prominent safety concern for female occupants, mitigated by a softer seatbelt and smaller airbag size near the chest. Obese occupants exhibited a higher likelihood of lower extremity injuries indicating a need for a knee airbag. A diverse set of improved restraint designs were effective in lowering injury risks, indicating that restraint adaptability is necessary for accounting for occupant diversity. CONCLUSIONS: This study investigated the effects of occupant size and shape variability, posture, and restraint design on injury risk for high-speed frontal crashes. More forward initial postures due to active safety features may decrease head, neck, and lower extremity injury risk, but may also increase chest injury risk. Safety concerns observed for large occupants include head strike-through and a conflict between head and chest injuries. Obese occupants had higher knee-thigh-hip injury risk. New restraints that adapt to occupant size and body shape may improve crash safety for all occupants. Further investigation is needed to confirm and extend the findings of this study.

An automated method to morph finite element whole-body human models with a wide range of stature and body shape for both men and women.

Field data analyses have shown that small female, obese, and/or older occupants are at increased risks of death and serious injury in motor-vehicle crashes compared with mid-size young men. The current adult finite element (FE) human models represent occupants in the same three body sizes (large male, mid-size male, and small female) as those for the contemporary adult crash dummies. Further, the time needed to develop an FE human model using the traditional method is measured in months or even years. In the current study, an improved regional mesh morphing method based on landmark-based radial basis function (RBF) interpolation was developed to rapidly morph a mid-size male FE human model into different geometry targets. A total of 100 human models with a wide range of human attributes were generated. A pendulum chest impact condition was applied to each model as an initial assessment of the resulting variability in response. The morphed models demonstrated mesh quality similar to the baseline model. The peak impact forces and chest deflections in the chest pendulum impacts varied substantially with different models, supportive of consideration of population variation in evaluating the occupant injury risks. The method developed in this study will enable future safety design optimizations targeting at various vulnerable populations that cannot be considered with the current models.