The force pyramid: a spatial analysis of force application during virtual reality brain tumor resection

Abstract

OBJECTIVE Virtual reality simulators allow development of novel methods to analyze neurosurgical performance. The concept of a force pyramid is introduced as a Tier 3 metric with the ability to provide visual and spatial analysis of 3D force application by any instrument used during simulated tumor resection. This study was designed to answer 3 questions: 1) Do study groups have distinct force pyramids? 2) Do handedness and ergonomics influence force pyramid structure? 3) Are force pyramids dependent on the visual and haptic characteristics of simulated tumors? METHODS Using a virtual reality simulator, NeuroVR (formerly NeuroTouch), ultrasonic aspirator force application was continually assessed during resection of simulated brain tumors by neurosurgeons, residents, and medical students. The participants performed simulated resections of 18 simulated brain tumors with different visual and haptic characteristics. The raw data, namely, coordinates of the instrument tip as well as contact force values, were collected by the simulator. To provide a visual and qualitative spatial analysis of forces, the authors created a graph, called a force pyramid, representing force sum along the z-coordinate for different xy coordinates of the tool tip. RESULTS Sixteen neurosurgeons, 15 residents, and 84 medical students participated in the study. Neurosurgeon, resident and medical student groups displayed easily distinguishable 3D "force pyramid fingerprints." Neurosurgeons had the lowest force pyramids, indicating application of the lowest forces, followed by resident and medical student groups. Handedness, ergonomics, and visual and haptic tumor characteristics resulted in distinct well-defined 3D force pyramid patterns. CONCLUSIONS Force pyramid fingerprints provide 3D spatial assessment displays of instrument force application during simulated tumor resection. Neurosurgeon force utilization and ergonomic data form a basis for understanding and modulating resident force application and improving patient safety during tumor resection.

Forces of Tool-Tissue Interaction to Assess Surgical Skill Level

“…To our knowledge, this is the first study that obtained force data from neurosurgical patients during surgery. Although other studies 12,14,15,22,27 have used surgical models or simulators in assessing force data, none of these represented an ideal, realistic surgical scenario that includes not only the physical properties but also the psychological stress related to the performance of surgery. The range of forces in this study was different from those previously reported using cadaver brain.…”

The Virtual Operative Assistant: An explainable artificial intelligence tool for simulation-based training in surgery and medicine

“…[39] However these systems do not allow for an assessment of quantitative instrument force application and instrument movements in a 3D operative environment nor provide verbal, visual and auditory feedback which may enhance the learning opportunities for the trainee. [10,21,40]…”

Machine learning distinguishes neurosurgical skill levels in a virtual reality tumor resection task

“…Whether these parametric features are the most appropriate or other metrics such as the force pyramid or automaticity will be more useful needs to be accessed. [17][18][19][20] Second, a simulated aspirator was utilized in the dominant hand which is not representative of the bimanual psychomotor skills and multiple instruments employed during patient tumor resections. Previous studies have demonstrated differences in ergonomics between right and left handed operators and this issue was not addressed in this investigation and deserves further study.…”

“…Previous studies have demonstrated differences in ergonomics between right and left handed operators and this issue was not addressed in this investigation and deserves further study. 17 Third, the different visual and haptic complexities of simulated tumors utilized and task duration may not adequately discriminate operator performance. More complex and realistic tumor scenarios with simulated bleeding involving use of bimanual instruments are being studied using classifiers which may be more useful.…”

“…Individual metric can be used to assess aspects of operator performance. Applied forces, 9,[17][18][19][20][21] bimanual dexterity, 15,22,23 and stress 23 have all been studied. An operator's performance metric(s) can be compared with previously defined proficiency benchmarks and that operator is placed into 1 of 2 or more groups with specific levels of psychomotor expertise.…”