An Original Endoluminal Magnetic Anastomotic Device Allowing Pure NOTES Transgastric and Transrectal Sigmoidectomy in a Porcine Model: Proof of Concept
ABSTRACT While experimental natural orifice transluminal endoscopic surgery (NOTES) sigmoid colectomies have been reported, pure NOTES anastomoses are restricted by the limited reach of commercially available circular staplers. MAGNAMOSIS is a set of self-orienting magnetic rings that can be delivered endoluminally throughout the colon to generate a compression anastomosis. Aim. To assess the feasibility of a pure NOTES transrectal (TR) and transgastric (TG) approach to perform any segmental colectomy.
One pig (50 kg) underwent the experimental procedure as follows: (a) creation of the TG access to the peritoneal cavity, (b) precise transluminal placement of the proximal MAGNAMOSIS ring, (c) creation of the TR access with the TEO and transrectal dissection of the sigmoid mesentery, (d) resection of the surgical specimen, (e) transrectal extraction of the specimen, (f) delivery and mating of the distal MAGNAMOSIS ring, and (g) closure of the TG and TR viscerotomies. The animal survived for 14 days at which time burst pressure and histology were performed.
A pure NOTES TR and TG segmental colectomy was performed in 139 minutes. The postoperative course was uneventful. The animal had a formed bowel movement including the magnetic rings on postoperative day 5. Endoscopic examination at postoperative day 14 revealed a patent anastomosis. Necropsy revealed no abscess or signs of peritonitis. Burst pressure was >198 mm Hg. The histology showed a sealed anastomosis with mild inflammation.
MAGNAMOSIS enabled a totally NOTES partial colectomy with combined TG and TR access. The flexible delivery options and low cost of manufacturing could make MAGNAMOSIS an attractive alternative to circular staplers.
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ABSTRACT: Aim. The concept of compression alimentary anastomosis is well established. Recently, magnetic axial alignment pressures have been encompassed within such device constructs. We quantify the magnetic compression force and pressure required to successfully achieve gastrointestinal and bilioenteric anastomosis by in-depth interrogation of the reported literature. Methods. Reports of successful deployment and proof of anastomotic patency on survival were scrutinized to quantify the necessary dimensions and strengths of magnetic devices in (a) gastroenteral anastomosis in live porcine models and (b) bilioenteric anastomosis in the clinical setting. Using a calculatory tool developed for this work (magnetic force determination algorithm, MAGDA), ideal magnetic force and compression pressure were quantified from successful reports with regard to their variance by intermagnet separation. Results. Optimized ranges for both compression force and pressure were determined for successful porcine gastroenteral and clinical bilioenteric anastomoses. For gastroenteral anastomoses (porcine investigations), an optimized compression force between 2.55 and 3.57 kg at 2-mm intermagnet separation is recommended. The associated compression pressure should not exceed 60 N/cm(2). Successful bilioenteric anastomoses is best clinically achieved with intermagnet compression of 18 to 31 g and associated pressures between 1 and 3.5 N/mm(2) (at 2-mm intermagnet separation). Conclusion. The creation of magnetic compression anastomoses using permanent magnets demonstrates a remarkable resilience to variations in magnetic force and pressure exertion. However, inappropriate selection of compression characteristics and magnet dimensions may incur difficulties. Recommendations of this work and the availability of the free online tool (http://magda.ucc.ie/) may facilitate a factor of robustness in the design and refinement of future devices.Surgical Innovation 04/2013; 21(1). DOI:10.1177/1553350613484824 · 1.34 Impact Factor
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ABSTRACT: Background and study aims: MAGNAMOSIS forms a compression anastomosis using self-assembling magnetic rings that can be delivered via flexible endoscopy. The system has proven to be effective in full-thickness porcine small-bowel anastomoses. The aim of this study was to show the feasibility of the MAGNAMOSIS system in hybrid endoscopic colorectal surgery and to compare magnetic and conventional stapled anastomoses. Methods: A total of 16 swine weighing 35 - 50 kg were used following animal ethical committee approval. The first animal was an acute model to establish the feasibility of the procedure. The subsequent 15 animals were survival models, 10 of which underwent side-to-side anastomoses (SSA) and 5 of which underwent end-to-side (ESA) procedures. Time to patency, surveillance endoscopy, burst pressure, compression force, and histology were assessed. Histology was compared with conventional stapled anastomoses. Magnetic compression forces were measured in various anastomosis configurations.Results: Colorectal anastomoses were performed in all cases using a hybrid NOTES technique. The mean operating time was 71 minutes. Mean time to completion of the anastomosis was similar between the SSA and ESA groups. Burst pressure at 10 days was greater than 95 mmHg in both groups. One complication occurred in the ESA group. Compression force among various configurations of the magnetic rings was significantly different (P < 0.05). Inflammation and fibrosis were similar between magnetic SSA and conventional stapled anastomoses. Conclusion: MAGNAMOSIS was feasible in performing a hybrid NOTES colorectal anastomosis. It has the advantage over circular staplers of precise endoscopic delivery throughout the entire colon. SSA was reliable and effective. A minimum initial compression force of 4 N appears to be required for reliable magnetic anastomoses.Endoscopy 06/2013; 45(8). DOI:10.1055/s-0033-1344119 · 5.20 Impact Factor
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ABSTRACT: The aim of our study was to assess the feasibility of minimally invasive digestive anastomosis using a modular flexible magnetic anastomotic device made up of a set of two flexible chains of magnetic elements. The assembly possesses a non-deployed linear configuration which allows it to be introduced through a dedicated small-sized applicator into the bowel where it takes the deployed form. A centering suture allows the mating between the two parts to be controlled in order to include the viscerotomy between the two magnetic rings and the connected viscera. Eight pigs were involved in a 2-week survival experimental study. In five colorectal anastomoses, the proximal device was inserted by a percutaneous endoscopic technique, and the colon was divided below the magnet. The distal magnet was delivered transanally to connect with the proximal magnet. In three jejunojejunostomies, the first magnetic chain was injected in its linear configuration through a small enterotomy. Once delivered, the device self-assembled into a ring shape. A second magnet was injected more distally through the same port. The centering sutures were tied together extracorporeally and, using a knot pusher, magnets were connected. Ex vivo strain testing to determine the compression force delivered by the magnetic device, burst pressure of the anastomosis, and histology were performed. Mean operative time including endoscopy was 69.2 ± 21.9 min, and average time to full patency was 5 days for colorectal anastomosis. Operative times for jejunojejunostomies were 125, 80, and 35 min, respectively. The postoperative period was uneventful. Burst pressure of all anastomoses was ≥110 mmHg. Mean strain force to detach the devices was 6.1 ± 0.98 and 12.88 ± 1.34 N in colorectal and jejunojejunal connections, respectively. Pathology showed a mild-to-moderate inflammation score. The modular magnetic system showed enormous potential to create minimally invasive digestive anastomoses, and may represent an alternative to stapled anastomoses, being easy to deliver, effective, and low cost.Surgical Endoscopy 01/2014; 28(5). DOI:10.1007/s00464-013-3360-2 · 3.31 Impact Factor