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Shadow depth cues and endoscopic task performance.

George B Hanna·Adrian B Cresswell·Alfred Cuschieri
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Abstract

HYPOTHESIS: A shadow-inducing laparoscopic system improves task performance. DESIGN: Experimental study was carried out using the Dundee Endoscopic Psychomotor Tester for objective assessment of task performance. The standard exercise consisted of passing a probe through 37 holes on the target plate in a random order. Shadow was induced by using separate ports for illumination and imaging of the target plate. Light direction-to-target (LDT) angles of 90 degrees, 75 degrees, and 60 degrees were investigated with each of the 90 degrees and 75 degrees optical axis-to-target view angles. SETTING: Research laboratory at the Surgical Skills Unit, Ninewells Hospital. PARTICIPANTS: Twenty medical students with no previous exposure to laparoscopic surgery. MAIN OUTCOME MEASURES: Success score, execution time, the force applied on the target, and angular deviations of the probe. RESULTS: With a 90 degrees optical axis-to-target angle, there was improvement in the success score using either 75 degrees or 60 degrees LDT angles compared with a 90 degrees LDT angle (P =.02, P =.01, respectively), but the execution time became longer (P =.008, P =.03, respectively). With a 75 degrees optical axis-to-target angle, there was improvement in the success score (P<.001), execution time (P<.001, P =.03, respectively), and horizontal and vertical deviations (P<.001) on using either 90 degrees or 60 degrees LDT angles compared with a 75 degrees LDT angle. CONCLUSION: Endoscopic task performance significantly improves with a system that provides illumination and shadows in the operative field.

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George B Hanna, Adrian B Cresswell, Alfred Cuschieri. 2002. Shadow depth cues and endoscopic task performance.. https://doi.org/10.1001/archsurg.137.10.1166

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