Magnetically Anchored Cautery Dissector Improves Triangulation and Depth Perception During Single Site Laparoscopic Cholecystectomy
Nabeel Arain*1, Erin Webb1, Deborah C. Hogg1, Richard Bergs3, Jeffrey a. Cadeddu2, Raul Fernandez3, Daniel J. Scott1
1Department of Surgery, University of Texas Southwestern Medical Center, Dallas, CA; 2Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX; 3Texas Manufacturing Assistance Center/Automation and Robotics Research Institute, University of Texas Arlington, Arlington, TX
Introduction: The purpose of this study was to evaluate operative outcomes and workload during Single Site Laparoscopy (SSL) using a Magnetic Anchoring and Guidance System (MAGS) cautery dissector compared to a conventional laparoscopic hook cautery dissector (LAP). Methods: Each dissector was used to perform SSL cholecystectomies in non-survival porcine models (n=6, 3 MAGS, 3 LAP). A single surgeon with a standardized team performed all procedures in a 2-day period. The device used in the first operation was randomized and devices were alternated thereafter. For both MAGS and LAP procedures, an umbilical multiport access device with two 5mm and one 12mm ports was used. For MAGS cases, the cautery device was inserted through the umbilical fascial defect, coupled magnetically, and the operating arm was deployed; 2 graspers (1 straight and 1 articulating) and a laparoscope were used for retraction and visualization, respectively. For LAP cases, 2 percutaneous retraction sutures, 1 articulating grasper, a hook cautery dissector, and a laparoscope were used. Operative outcomes and surgeon ratings (scale 1-5, 1=superior rating) were recorded. Workload was assessed by the surgeon and the assistant using a previously validated NASA-TLX rating tool which assessed mental, physical, temporal, performance, effort, and frustration levels (scale 1-10, 1=superior rating). Comparisons used Mann-Whitney tests; p<0.05 was considered significant.Results: Pig weight was 54 ± 1.9 kg and compressed abdominal wall thickness for MAGS was 1.8 ± 0.1 cm. Operative outcomes and surgeon ratings for MAGS and LAP (respectively) were: operative time 25.3 ± 1.5 vs. 28.7 ± 6.4 minutes (n.s.), EBL 5.0 ± 0 vs. 28.3 ± 40.4 cc (n.s.), critical view achievement 1.0 ± 0 vs. 2.0 ± 1.0 (n.s.), ease of dissection 2.0 ± 0 vs. 3.7 ± 0.6 (n.s.), ergonomics 1.0 ± 0 vs. 4.0 ± 0 (n.s.), technical challenges 2.0 ± 0 vs. 3.7 ± 0.6 (n.s.). For both MAGS and LAP cases, complete cholecystectomies were achieved and bile spillage was similar. For MAGS, depth perception and instrument triangulation were excellent and there were no complications. For LAP, the parallel arrangement of the laparoscope and the dissector hindered depth perception and caused numerous instrument conflicts; complications included a superficial liver laceration from a Keith needle and an inadvertent burn to the diaphragm during gallbladder dissection. For MAGS and LAP (respectively), surgeon workload ratings were 2.6 ± 0.2 vs. 5.6 ± 1.1 (p<0.001) and assistant ratings were 4.8 ± 0.8 vs. 5.8 ± 1.9 (n.s.). Conclusion: These data suggest that using the MAGS device for SSL cholecystectomy results in equivalent or better operative outcomes and less workload compared to using only laparoscopic instrumentation, since better triangulation and depth perception are afforded. Additional investigations are encouraged.
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