Electromagnetic motion analysis in the assessment of surgical skill: Relationship between time and movement

Introduction: Electromagnetic motion analysis is a promising method of assessing surgical skill in a skills-laboratory setting. There is a very strong correlation between movement and time data, and this study was conducted to determine whether this relationship is fixed, or whether it can vary. Methods: After a pilot study, four subjects were recruited. Each performed 30 trials of a simple standardized suturing task, alternating between 'normal', 'precise', and 'fast' strategies. The number of movements, and time to complete each task were recorded. Results: Comparing the 'fast' to 'normal' strategies, there was a significant decrease in total number of movements per trial (P < 0.001), and time taken (P < 0.001). Regression analysis was performed to examine the relationship between the time taken and the number of movements, and revealed significant differences between both the fast (P = 0.006), and precise (P = 0.002) strategies, when compared to the normal strategy. Discussion: This study confirms that the relationship between time and movements is not fixed, but varies with the operative strategy adopted for this simple suturing task.