Magnetically Anchored Camera and Percutaneous Instruments Maintain Triangulation and Improve Cosmesis Compared to Single-site and Conventional Laparoscopic Cholecystectomy

Nabeel A Arain, MD MBA, Luisangel Rondon, MD, Deborah C Hogg, BS, Jeffrey A Cadeddu, MD, Richard Bergs, MS, Raul Fernandez, PhD, Daniel J Scott, MD. University of Texas Southwestern Medical Center at Dallas (Departments of Surgery and Urology), University of Texas at Arlington (Texas Manufacturing Assistance Center)


Introduction: The purpose of this study was to evaluate operative outcomes and ergonomics using a new generation magnetically anchored camera (Magnetic Positioning Platform – MPP) in conjunction with novel 3mm percutaneous instruments (Percutaneous Surgical Set – PSS) compared to single-site (SSL) and conventional laparoscopic (LAP) cholecystectomy techniques.

Methods: Surgery residents and fellows (n=4) each performed 3 cholecystectomies (live porcine models) using 3 techniques (MPP/PSS, SSL, LAP; randomized order following standardized tutorials). For MPP/PSS, a 70º FOV magnetic camera was introduced through an umbilical fascial defect and a 12mm trocar was placed (alongside the camera tether) for conventional instruments. Two 3mm instrument shafts were percutaneously inserted, intracorporeally mated with 5mm working heads, and used for retraction. For SSL, a multiport-access device was used; percutaneous retraction sutures, an articulating grasper, a hook-cautery, and a 5mm laparoscope were used. For LAP, a conventional 4-port technique (three-5mm and one-12mm trocar) was used. A single faculty surgeon served as proctor and assistant for all procedures. Operative outcomes were recorded. Surgeon-ratings (1-5 scale; 1=superior) were used to evaluate ease of dissection, ergonomics, technical challenges, and significant problems associated with each technique. Surgeon-workload was measured using a validated NASA-TLX survey (1-10 scale; 1=superior). A global rating survey (1-10 scale; 10=superior) was used to assess surgeon preference for each technique. Comparisons used ANOVA on ranks (Kruskal-Wallis); p<0.05 was considered significant.

Results: No significant differences were detected for operative times, critical views, adequacy of dissection, and bile-spillage; blood loss (cc) was significantly higher for SSL (16.3 ± 10.3) vs. LAP (2.8 ± 1.5, p<0.05) but not for MPP/PSS (4.8 ± 3.8). Inadvertent damage to adjacent structures occurred in SSL (1-Keith needle stick to the colon, 1-cystic duct avulsion, and 1-burn to the diaphragm) but not for MPP/PSS or LAP. Combined incision-length (mm) was significantly smaller for MPP/PSS (29.3 ± 2.8) and SSL (29.3 ± 2.5) compared to LAP (48.0 ± 3.6, p<0.05). Compared to SSL (3.6 ± 0.5), surgeon-ratings significantly favored MPP/PSS (2.8 ± 0.4) and LAP (1.7 ± 0.2, p<0.05); ergonomics and technical challenges were both rated significantly inferior for SSL (4.3 ± 1.0, 3.8 ± 0.5, respectively) vs. LAP (1.5 ± 0.6, 2.0 ± 0.8, respectively; p<0.05) but not for MPP/PSS (2.5 ± 1.0, 3.0 ± 0.8, respectively). Both MPP/PSS (4.5 ± 0.5) and SSL (4.8 ± 1.0) were associated with significantly higher workload than LAP (2.5 ± 0.6, p<0.05). Surgeon preference was significantly higher for LAP (8.7 ± 1.3) vs. SSL (5.8 ± 2.0, p<0.05), but not for MPP/PSS (7.1 ± 1.8). Cosmesis was significantly better for MPP/PSS (9.5 ± 0.6) vs. LAP (6.5 ± 2.4, p<0.05) but not for SSL (8.8 ± 1.3).

Conclusion: For senior level trainees, difficulties associated with SSL may limit their performance. The MPP/PSS technique allows triangulation and fewer technical difficulties compared to SSL and better cosmesis compared to LAP. Additional benefits may include less pain, reduced port-site herniation, and shorter recovery. Further development of these devices is warranted.

Disclaimer: These devices are not approved by the FDA for human use.

Session Number: SS02 – Instrumentation / Ergonomics
Program Number: S009

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