Surgical technique

Background. Using laparoscopic ultrasonography (LUS) is challenging for both novice and experienced ultrasonographers. The major difficulty surgeons experience is understanding the orientation of the ultrasonography image. The purpose of this study was to assess whether providing surgeons with orientation information improves their ability to interpret LUS images. Methods. We performed a LUS examination on a 25-kg pig and simultaneously digitized video from the laparoscopic camera, the LUS, and a novel orientation system. From the video recordings, 12 different clips of intra-abdominal anatomy were prepared. Twenty surgeons (18 staff, 2 fellows) volunteered to participate in an experimental crossover study. Test subjects reviewed the LUS clips along with the laparoscopic video images and the orientation display. Controls reviewed the LUS clips with only the laparoscopic video images. Diagnostic accuracy was compared by using the odds ratio. Results. For all vessels, the orientation display improved the odds ratio for correctly identifying structures from 3.7 to 8.9 (P = .02). For arteries, the orientation display improved the odds ratio from 2.4 to 9.6 (P = .01). For veins, the orientation display improved the odds ratio from 4.4 to 13.6 (P = .04). Conclusions. Providing orientation information significantly improves a surgeon’s ability to interpret LUS images. (Surgery 2004;136:84-92.)