Magnetic Anastomosis Research Articles

Staged repair of esophageal atresia: Pouch approximation and catheter-based magnetic anastomosis

Esophageal atresia (EA) without tracheoesophageal fistula is characterized typically by a long gap between the discontinuous upper and lower esophageal pouches. In these challenging patients, initial esophagoesophagostomy is often not possible due to excessive tension produced when approximating the two pouches. This tension poses significant risk for pouch retraction, anastomotic leak, mediastinitis, and subsequent esophageal stricture. Consequently, multiple strategies exist to induce pouch lengthening and to achieve full continuity of native esophageal tissue, which if not accomplished, requires interpositions of stomach, small bowel, or colon to establish deglutition. One strategy involves a two-staged approach: first, after a period of growth into early infancy, the two esophageal pouches are suture-approximated without anastomosis, and second, repeat surgery is performed to establish luminal continuity once tension between the pouches has resolved. Esophageal growth and continuity are thereby achieved. Here, we describe an innovative, staged treatment approach for long-gap EA in two premature babies who initially underwent suture-approximation of the esophageal pouches at 3 months of age, followed by catheter-based magnetic compression anastomosis 10 weeks later. In both babies, the magnetic procedure allowed preservation of the gained full esophageal length, established successful esophageal canalization, created a leak-free anastomosis, and prevented the need for additional thoracotomy to accomplish these goals.

Magnets in the GI tract

Magnets in the GI tract

MAGNAMOSIS IV: magnetic compression anastomosis for minimally invasive colorectal surgery

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. 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. 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. 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.

Totally Endoscopic Magnetic Enteral Bypass by External Guided Rendez-Vous Technique

This study aimed to assess the feasibility of a totally endoscopic enteral bypass using a self-orienting, dual ring, magnetic anastomosis system (MAGNAMOSIS) guided by a magnetic tracking system (3D METRIS). In an anesthetized pig, 2 endoscopes were advanced, one each into the stomach and the colon. Both endoscopes were equipped with a MAGNAMOSIS ring secured with an endoscopic snare and a 3D METRIS within one working channel. The whole procedure was followed laparoscopically. The tracking system guided tips of endoscopes to a "rendez-vous" location between the colon and stomach. MAGNAMOSIS magnets automatically joined in the correct configuration when guided to within 2 cm of each other. At necropsy, magnetic rings were secure without entrapment of excess bowel or mesentery. An endoscopic enteral bypass with magnetic anastomosis and magnetic tracking device was feasible. More accurate tracking and advanced techniques could enable endoscopic bypasses at multiple sites in the gastrointestinal tract.

Endoscopic magnetic gastroenteric anastomosis for palliation of malignant gastric outlet obstruction: a prospective multicenter study

Palliation of malignant gastric outlet obstruction remains challenging. Although there are 2 established treatment options, ie, surgical gastrojejunostomy and endoscopic duodenal stent insertion, there is an ongoing search for a technique that would combine the safety and rapid effect of duodenal stent placement with the long-term efficacy and low reintervention rate of a surgical gastrojejunostomy. To investigate the safety and success rate of endoscopic creation of a gastroenteric anastomosis formed by magnetic compression and stent placement. Prospective, multicenter cohort study. Four referral centers. The expected number of patients with symptomatic malignant gastric outlet obstruction to be included at the participating hospitals during a year was 40. Because of a serious adverse device event, the study was terminated after inclusion of 18 patients. Creation of an endoscopic gastroenteric anastomosis by using the Cook Magnetic Anastomosis Device with transanastomotic deployment of a self-expandable stent. Primary endpoints were safety and success rate associated with the creation of an endoscopic gastrojejunostomy by using a magnetic anastomotic device with transanastomotic deployment of a self-expandable stent. Because of a serious adverse event, the study was terminated prematurely. A success rate of 66.7% (12 of 18 patients) was achieved; 1 serious adverse event (stent perforation) occurred leading to the death of the patient. Three patients (25%) experienced an adverse device effect (stent migration). Small sample size, lack of a control group. Endoscopic creation of a gastroenteric anastomosis by magnetic compression is feasible and safe; however, the necessity of a stent led to serious morbidity and even mortality in this study. The current system can therefore not be recommended for clinical use.

Endoscopic Magnetic Anastomosis Device for Palliation of Malignant Gastric Outlet Obstruction: Short Term Results of a Prospective Multicenter Study

Endoscopic Magnetic Anastomosis Device for Palliation of Malignant Gastric Outlet Obstruction: Short Term Results of a Prospective Multicenter Study

Magnamosis: magnetic compression anastomosis with comparison to suture and staple techniques

Purpose An ideal anastomosis between hollow viscera should be easily performed, strong, and operator independent. We hypothesized that transluminal attraction between magnets in the intestine could be harnessed to create an intestinal compression anastomosis (magnamosis) with these characteristics. We further hypothesized that variation of attraction force and geometry of compression would affect the quality of the intestinal anastomosis. Methods We designed a self-orienting device composed of 2 neodymium-iron-boron magnets affixed to polytetrafluoroethylene moldings. Two topologies were evaluated: one designed with ‘uniform’ compression and the other with ‘gradient’ compression. Sixteen young adult pigs ( Sus scrofa) underwent laparotomy with creation of a magnetic side-to-side anastomosis: 8 with the uniform device and 8 with the gradient device. Each also had a stapled anastomosis, and 5 had an additional hand-sutured anastomosis. Animals were euthanized at 1, 2, and 3 weeks after operation, then anastomoses were compared on the basis of gross appearance, histology, functional radiography, and mechanical integrity. Results All magnetic devices formed patent anastomoses without leak. One stapled anastomosis resulted in a contained leak. Mechanical integrity of magnetic anastomoses was not statistically significantly different from staple or suture counterparts, and there was a trend toward greater strength with magnetic anastomoses. Comparison between device types revealed the gradient device trended toward greater strength and earlier patency (67% vs 33% at 1 week). There was no evidence of stenosis, and histologic examination demonstrated tissue remodeling with mucosal and serosal apposition across the magnamoses. Conclusions The magnetic compression anastomosis (magnamosis) device is a safe and effective means of sutureless full-thickness intestinal anastomosis with serosal apposition in a pig model. Gradient compression is superior to uniform compression. This technique is compatible with endoscopic and natural orifice approaches.

Does the Ventrica Magnetic Vascular Positioner (MVP®) for Coronary Artery Bypass Grafting Significantly alter Local Fluid Dynamics? a Numeric Study

Automatic devices have been recently introduced to make the anastomosis procedure quick and efficient when creating a coronary bypass on the beating heart. However, the implantation of these devices could modify the graft configuration, consistently affecting the hemodynamics usually found in the traditional anastomosis. As local fluid dynamics could play a significant role in the onset of vessel wall pathologies, in this article a computational approach was designed to investigate flow patterns in the presence of the Ventrica magnetic vascular positioner (Ventrica MVP) device. A model of standard hand-sewn anastomosis and of automated magnetic anastomosis were constructed, and the finite volume method was used to simulate in silico realistic graft hemodynamics. Synthetic analytical descriptors -- i.e., time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and helical flow index (HFI) -- were calculated and compared for quantitative assessment of the anastomosis geometry hemodynamic performance. In this case study, the same most critical region was identified for the 2 models as the one with the lowest TAWSS and the highest OSI (TAWSS=0.229, OSI=0.255 for the hand-sewn anastomosis; TAWSS=0.297, OSI=0.171 for the Ventrica MVP(R)). However, the shape of the Ventrica MVP does not induce more critical wall shear stresses, oscillating flow and damped helicity in the graft fluid dynamics, as compared with conventional anastomosis. We found that the use of the Ventrica MVP for the case study under investigation was not associated with more critical fluid dynamics than with conventional hand-sewn anastomosis. Thereby, the device could facilitate beating heart and minimally invasive coronary artery bypass grafting without increasing local hemodynamic-related risks of failure.

R-010 磁性体を用いた食道食道吻合法(低侵襲手術II, 第44回日本小児外科学会学術集会)

R-010 磁性体を用いた食道食道吻合法(低侵襲手術II, 第44回日本小児外科学会学術集会)

Technique and safety of magnetic anastomoses

Aims: In the last few years many clinical studies were published examining a new technique of creating anastomoses, namely using magnets to perform different anastomoses (e.g. gastroenterostomy or bilioenterostomy). Our group examined the technical execution and safety of endoscopic gastroenteric anastomosis using magnets (EGAM) and the technique with a new potential therapeutic use of magnets for treating Zenker's diverticulum. Materials and methods: The EGAM procedures were performed with endoscopic and fluoroscopic guidance on biogenic specimen taken from slaughtered domestic pigs. Two coated rare-earth magnets (NdFeB, magnetic remanency: 1.2 Tesla, H: 5mm, D: 10mm) were introduced perorally by guide wires and duodenal probes. The first was positioned in the first jejunal loop, the second in the stomach, and finally they were matted transmurally to create EGAM. To examine the safety of magnetic anastomoses, another experiment was performed in male Whistar rats. The magnets (H: 1mm, D: 1mm) were surgically placed into the digestive tract to make gastroenteric anastomosis. The rats were monitored by fluoroscope and the anastomoses were examined histologically. Performing the experimental intervention on biogenic model to treat Zenker's diverticulum the first magnet (H: 40mm, D: 8mm) was placed into the diverticulum, the second one into the esophagus and they were matted through the septum including the cricopharyngeal muscle. Results: The technique of making EGAM was easy and rapid to carry out. Thus these interventions probably will not need any anesthesia. The anastomoses in the rats were developed by the 7th-10th postoperative day. There was no leakage and the adhesion was wide enough, but the magnets were damaged by the gastric acid. The experiment of treating Zenker's diverticulum was performed successfully and in our opinion it could be a new indication of using magnets. Conclusions: EGAM is safe enough to create anastomosis. More animal investigations are needed to find the ideal power and shape of magnets. To protect the magnets it may be necessary to cover them with some material, e.g. silicon.