Electromagnetic tool for the endoscopic creation of colon anastomoses—development and feasibility assessment of a novel anastomosis compression implant approach

Abstract

Background: Colorectal anastomoses are among the most commonly performed interventions in abdominal surgery, while associated patient trauma is still high. Most recent trends of endoscopic anastomosis devices integrate magnetic components to overcome the challenges of minimally invasive surgery. However, the mutual attraction between magnetic implant halves may increase the risk of inadvertently pinching healthy structures. Thus, we present a novel anastomosis device to improve system controllability and flexibility. Methods: A magnetic implant and an applicator with electromagnetic control units were developed. The interaction of magnetic implants with the electromagnets bears particular challenges with respect to the force-related dimensioning. Here, attraction forces must be overcome by the electromagnet actuation to detach the implant, while the attraction force between the implant halves must be sufficient to ensure a stable connection. Thus, respective forces were measured and the detachment process was reproducibly investigated. Patient hazards, associated with resistance-related heating of the coils were investigated. Results: Anastomosis formation was reproducibly successful for an implant, with an attraction force of 1.53 ± 0.3 N, resulting in a compression pressure of 0.0048Nmm2. The implant was reproducibly detachable from the applicator at the anastomosis site. Coils heated up to a maximum temperature of Tmax= 41.6 ± 0. 1 ∘C. Furthermore, we were able to establish a neat reconnection of intestinal bowel endings using our implant. Discussion: As we achieved nearly equal compression forces with our implant as other magnetic anastomosis systems did (Magnamosis™: 1.48 N), we concluded that our approach provides sufficient holding strength to counteract the forces acting immediately postoperatively, which would eventually lead to an undesired slipping of the implant halves during the healing phase. Based on heat transfer investigations, preventive design specifications were derived, revealing that the wall thickness of a polymeric isolation is determined rather by stability considerations, than by heat shielding requirements.