Evaluation of a navigation grid to increase the efficacy of instrument movement during laparoscopic surgery.

INTRODUCTION: The objective of this study was to determine whether or not a navigation grid (NG) with a coordinate system overlaid on a laparoscopic display might allow attending surgeons to more easily and precisely direct their assistants' instruments to specific sites in a simulated laparoscopic field. MATERIALS AND METHODS: In this randomized, crossover study, we evaluated the impact of the NG on an individual's performance in a target identification task. One hundred thirty pins served as targets in a standard laparoscopic box trainer. An instructor guided 30 naive subjects to locate five randomly selected targets each, either with verbal instructions alone or with verbal instructions supplemented by a localizing NG. The NG appeared on both the instructor's and the participants' monitors, but the randomly selected targets were visible only to the instructor. Each participant performed 10 trials alternating between with and without the NG. The outcome measure was the interval (in seconds) from when the laparoscopic instrument was first visible in the field to when the subject grasped the correct target with forceps. RESULTS: The mean time to identify each selected target was significantly shorter with the NG (9.150±3.43 seconds) than without (12.53±4.89 seconds) (P<.0001). This effect was sustained throughout the learning curve. CONCLUSIONS: The use of the NG appears to improve efficiency in guiding an instrument to randomly identified targets within a laparoscopic field. The use of an NG may reduce the time required to move instruments to specific sites during surgery.