Magnetic retraction of bowel by intraluminal injectable cyanoacrylate-based magnetic glue

Magnetic retraction offers advantages over physical retraction by graspers because of reduced tissue trauma. The objectives of this study are to investigate a novel method of magnetisation of bowel segments by intraluminal injection of magnetic glue and to demonstrate the feasibility of magnetic retraction of bowel with sufficient force during minimal access surgery. Following an initial materials characterisation study, selected micro-particles of stainless steel (SS410-μPs) were mixed with chosen cyanoacrylate glue (Loctite 4014). During intra-luminal injection of the magnetic glue using ex-vivo porcine colonic segments, a magnetic probe placed at the injected site ensured that the SS410-μPs aggregated during glue polymerisation to form an intra-luminal mucosally-adherent coagulum. The magnetised colonic segments were retracted by magnetic probes (5 and 10-mm) placed external to the bowel wall. A tensiometer was used to record the retraction force. With an injected volume of 2mL in a particle concentration of 1 g/mL, this technique produced maximal magnetic retraction forces of 2.24 ± 0.23 N and 5.11 ± 0.34 N (n =20), with use of 5 and 10-mm probes respectively. The results indicate that the formation of an intra-luminal coagulum based on SS410-μPs and Loctite 4014 produces sufficient magnetic retraction for bowel retraction.