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INTRODUCTION: Magnetic Anchoring and Guidance System (MAGS) instruments consist of an internal surgical device coupled across the abdominal wall using an external handheld magnet. The purpose of this study was to evaluate the histological effects of abdominal wall compression using the MAGS platform.METHODS: Cholecystectomy was performed in 4 porcine models (41-53 kg, 2 non-survival, 2 survival (72 hrs & 14 days) using a single site laparoscopic (SSL) approach with percutaneous gallbladder retraction sutures. Through a 2.5cm umbilical incision, a MAGS cautery dissector was inserted. A multiport access device allowed use of a laparoscope and other instruments. The MAGS cautery instrument was used to perform the entire dissection. The abdominal wall areas corresponding to the region occupied by the MAGS platform were grossly examined internally (laparoscope) and externally (direct visualization) for signs of tissue damage and marked to facilitate accurate specimen harvesting. At necropsy, abdominal wall thickness was measured and the peritoneal cavity was examined. A board-certified pathologist performed histological evaluation of the harvested specimens. NADH stains evaluated cellular viability and H&E sections evaluated necrosis, acute inflammation, ulceration, and vascular congestion. All findings were scored using standardized grading scales.RESULTS: All procedures were completed using a SSL approach with no complications; gallbladder dissection time was 36 minutes (15-49). The MAGS cautery instrument facilitated excellent triangulation with minimal instrument conflicts when used in conjunction with only one laparoscopic instrument. Uncompressed and compressed abdominal wall thicknesses were 2.1cm (1.4-2.5) and 1.4cm (1.1-1.8), respectively. In all 4 animals, very mild erythema was noted immediately post procedure in the areas corresponding to the outer edges of the rectangular external magnet; this erythema was non-visible within 20 minutes. In 2 animals (pigs 3 & 4), mild blanching was noted on the peritoneal surface and 1 animal (pig 3) exhibited a 5mm area of petechiae. Necropsy demonstrated no adhesions. All specimens demonstrated no light microscopic evidence of necrosis, atrophy, or loss of normal NADH staining. No ulceration, acute inflammation, or vascular congestion was detected. CONCLUSION: This study demonstrated that use of the MAGS cautery dissector for a SSL cholecystectomy was advantageous in providing triangulation and did not result in any significant gross or microscopic tissue damage, despite the thin abdominal wall of the porcine model. These data support important safety aspects of the MAGS platform for planned use in humans.