Magnetic anchoring and Guidance System instrumentation for laparo-endoscopic single-site surgery/natural orifice transluminal endoscopic surgery: Lack of histologic damage after prolonged magnetic coupling across the abdominal wall

Objectives: To study the potential pathologic effect of prolonged compression of abdominal wall between the components. Magnetic Anchoring and Guidance System (MAGS) instruments ameliorate some of the challenges in triangulation created by laparo-endoscopic single-site and natural orifice translumenal endoscopic surgery. They consist of an intracorporeal magnetic device coupled to an external hand-held magnet used to anchor and "steer" it around the peritoneal cavity. Methods: Three pigs (45.5-48.6 kg) underwent laparoscopic placement of magnetic devices in 4 quadrants, with the devices left in place for 2 or 4 hours. Full-thickness abdominal wall sections (mean 2.1 cm thick) where each MAGS platform was placed plus a control were harvested at 0, 2, or 14 days after surgery. Histologic assessment was then performed. Results: Beyond mild blanching of the peritoneal surface with a few petechiae immediately after internal component removal, no gross tissue damage was seen. These changes were undetectable by 48 hours and no intra-abdominal adhesions were identified at necropsy. NADH stain for tissue viability in the 4 nonsurvival specimens showed no tissue damage. Hematoxylin and eosin stain showed no necrosis of either superficial or deep muscle, skin, or subcutaneous fat tissue in all 12 specimens when compared with the control. Conclusions: MAGS instruments do not appear to cause tissue damage or adverse clinical outcomes when coupled across thin porcine abdominal walls for up to 4 hours. Because the distance across the abdominal wall is generally greater in adult human beings, these findings support the further clinical development of magnetic instruments to be used in human patients.