Evaluation of sutureless anastomosis after ileostomy takedown using the self-forming magnet anastomosis system in a porcine model

Small bowel magnetic compression anastomosis creation for bypass procedures in a porcine model

BACKGROUND

Stapled and hand-sewn techniques dominate gastrointestinal anastomotic procedures. These techniques are effective but not without flaws. Retained foreign bodies, pathways from mucosa to serosa, and increased scar tissue are some of the drawbacks, and can lead to postoperative complications. The GI Windows Flexagon™ system utilizes self-forming magnets (SFM's) to create anastomoses by compression, sealing serosa to serosa, leaving no foreign bodies. Combining the Flexagon™ SFM with the OTOLoc™ device (implant with a central lumen which provides radial support to the enterotomies), enables immediate flow through the anastomosis and facilitates creation of enteral bypass procedures unique to this technology. We sought to compare the safety and efficacy of the GI Windows Flexagon™ and OTOLoc™ technologies against conventional stapling.

METHODS

A preclinical study was conducted on 14 Yorkshire swine to compare laparoscopic magnetic and stapled duodenoileostomies and jejunojejunostomies. Study endpoints included: adverse or serious adverse events, anastomotic burst pressure, adhesions, histopathology, and bacterial ingress. A Likert scale was used to assess the usability of the devices.

RESULTS

All procedures were successfully completed via laparoscopic approach; no adverse or serious adverse events were observed at the 42-day endpoint. All SFM's were expelled in less than 20 days. Average anastomotic burst pressure was 129.2 mmHg for SFM compared to 79.4 mmHg in stapled controls. Adhesion scores were similar between groups. Histopathology revealed that magnetic anastomoses have less intestinal wall distortion, fewer signs of chronic inflammation, and no bacterial ingress. The usability of all devices was reported as "Easy" or "Very Easy."

CONCLUSION

GI Windows magnetic compression anastomoses creation in this porcine model revealed an overall ease of use, all while demonstrating procedural feasibility, safety, and clinical effectiveness. Surprisingly, in nearly all results assessed, SFM anastomoses were found to be comparable to the control stapled anastomoses in regard to structural, physiological, and histological endpoints.

Comparative study of cylindrical vs circular ring magnets for colonic anastomosis in rats

BACKGROUND

Magnetic compression anastomosis (MCA) offers a simple and reliable technique for inducing anastomoses at any point along the digestive tract. Evidence regarding whether the design of the MCA device influences the anastomosis effect is lacking.

AIM

To investigate any difference in the side-to-side colonic anastomosis effect achieved with cylindrical vs circular ring magnets.

METHODS

We designed cylindrical and circular ring magnets suitable for side-to-side colonic anastomosis in rats. Thirty Sprague-Dawley rats were randomly divided into a cylindrical group, circular ring group, and cylindrical–circular ring group (n = 10/group). Side-to-side colonic anastomosis was completed by transanal insertion of the magnets without incision of the colon. Operation time, perioperative complications, and magnet discharge time were recorded. Rats were euthanized 4 weeks post-operatively, and anastomotic specimens were obtained. The burst pressure and anastomotic diameter were measured sequentially, and anastomosis formation was observed by naked eye. Histological results were observed by light microscopy.

RESULTS

In all 30 rats, side-to-side colonic anastomosis was completed, for an operation success rate of 100%. No postoperative complications of bleeding and intestinal obstruction occurred, and the postoperative survival rate were 100%. The operation time, magnet discharge time, anastomotic bursting pressure, and anastomotic diameter did not differ significantly among the three designs (P > 0.05). Healing was similar across the groups, with gross specimens showing good anastomotic healing and good mucosal continuity observed on histological analysis.

CONCLUSION

This study found no significant difference in the establishment of rat side-to-side colonic anastomosis with the use of cylindrical vs circular ring magnets.

Magnetic duodenoileal anastomosis with sleeve gastrectomy: a prospective multicenter study

BACKGROUND

Magnetic digestive anastomosis has the potential to reduce anastomotic complications and complexity. We report the 1-year results of a new surgical technique using Self-forming Neodymium magnet Anastomosis Procedure with Sleeve gastrectomy (SNAP-S; GI Windows).

METHODS

This was a prospective, nonrandomized multicenter trial. Participants with type 2 diabetes (T2D) who met criteria for metabolic surgery were recruited. A dual-path duodenoileal anastomosis was created at 300 cm from the ileocecal valve using circular magnetic anastomosis. The proximal magnet was deployed by endoscopy and the distal one by laparoscopy. Sleeve gastrectomy was performed at the same time. Data are reported as mean ± standard deviation or percentage.

RESULTS

Nineteen subjects with T2D were recruited (age 45 ± 9 years, body mass index 43 ± 5 kg/m2, hemoglobin A1C 7.3 ± 1.3%). There was no conversion, mortality, or adverse event related to the magnetic anastomosis. Mean time for anastomosis creation was 32 ± 10 minutes. One patient was not implanted because of an inability to bring the ileum to the duodenum. Follow-up rate at 12 months was 95%. A total of 41 procedure-related adverse events were recorded during follow-up. Seven events in 4 subjects were considered serious. Total weight loss at 3, 6, and 12 months was 22 ± 19%, 28 ± 19%, and 31 ± 11%, respectively. Excess weight loss was 45 ± 14%, 59 ± 21%, and 78 ± 33%, respectively. All patients had an hemoglobin A1C ≤6.0% at 12 months with complete T2D remission in 78%.

CONCLUSION

The SNAP-S procedure is feasible with a low complication rate related to the anastomotic technique itself. The SNAP-S procedure provides significant weight loss and improvement of comorbidities. Additional prospective data are needed to better define the place of SNAP-S procedure.

Magnetic compression anastomosis gastrojejunostomy: feasibility and efficacy of a novel device in a swine model

BACKGROUND

Means of addressing technical challenges in forming gastrojejunostomy (GJ) anastomoses and maintaining their patency are sought.

OBJECTIVES

Evaluation of preclinical feasibility and healing efficacy of a novel linear magnetic compression anastomosis (MCA) device to form a patent GJ versus sutured jejunal enterotomy (JE) sites in swine.

SETTING

Single-center veterinary testing facility.

METHODS

Feasibility of 3 prototype sizes (4, 6, and 8 cm) of a metal MCA device (MCAD) to form a patent GJ was evaluated over 6 weeks. A distal magnet was laparoscopically inserted in the jejunum, a proximal magnet was placed gastroscopically in the stomach; magnets were aligned to gradually form an anastomosis, self-detached, and be expelled. At necropsy, MCAs were assessed for patency and compared with JE tissues to evaluate wound healing.

RESULTS

MCADs aligned at the GJ location without complications. In 5/6 MCAD pairs, dislodgement occurred between 7 and 26 days; expulsion 13-31 days; 1 MCAD pair was retained in the stomach. At necropsy, all pigs were healthy, gaining a mean 15.0 kg. Anastomoses were not adequately patent in 2/4 pigs receiving the 4-cm or 6-cm MCADs because their linear length was too small. But, anastomoses of both pigs receiving the 8-cm MCADs maintained full patency. Minimal inflammation and fibrosis were seen in MCA specimens versus sutured enterotomies.

CONCLUSIONS

A novel linear MCA device was feasible and effectively created a patent GJ anastomosis in swine with minimal inflammation and fibrosis. The MCAD may be appropriate for clinical evaluation.

Feasibility experiment of a novel deformable self-assembled magnetic anastomosis ring (DSAMAR) for gastrointestinal anastomosis through a natural orifice

Although the application of magnetic compression anastomosis is becoming increasingly widespread, the magnets used in earlier studies were mostly in the shape of a whole ring. Hence, a deformable self-assembled magnetic anastomosis ring (DSAMAR) was designed in this study for gastrointestinal anastomosis. Furthermore, its feasibility was studied using a beagle model. The designed DSAMAR comprised 10 trapezoidal magnetic units. Twelve beagles were used as animal models, and DSAMARs were inserted into the stomach and colon through the mouth and anus, respectively, via endoscopy to achieve gastrocolic magnamosis. Surgical time, number of failed deformations, survival rate of the animals, and the time of magnet discharge were documented. A month later, specimens of the anastomosis were obtained and observed with the naked eye as well as microscopically. In the gastrocolic anastomosis of the 12 beagles, the procedure took 65-120 min. Although a deformation failure occurred during the operation in one of the beagles, it was successful after repositioning. The anastomosis was formed after the magnet fell off 12-18 days after the operation. Naked eye and microscopic observations revealed that the anastomotic specimens obtained 1 month later were well-formed, smooth, and flat. DSAMAR is thus feasible for gastrointestinal anastomosis under full endoscopy via the natural orifice.

Influence of different magnetic forces on the effect of colonic anastomosis in rats

BACKGROUND

Despite much work having been conducted on magnetic compression anastomosis (MCA) in the digestive tract, there are no reports on the influence of magnetic force on the anastomosis.

AIM

To investigate the effect of different magnetic force magnets on the MCA of the digestive tract.

METHODS

Two groups of magnets of the same sizes but different magnetic forces were designed and produced. A total of 24 Sprague-Dawley rats were randomly assigned into two groups (powerful magnet group and common magnet group), with 12 rats in each group. Two types of magnets were used to complete the colonic side-to-side anastomosis of the rats. The operation time and magnet discharge time were recorded. The anastomotic specimens were obtained 4 wk after the operation and then the burst pressure and diameter of the anastomosis were measured, and the anastomosis was observed via the naked eye and subjected to histological examination.

RESULTS

The magnetic forces of the powerful and common magnet groups at zero distance were 8.26 N and 4.10 N, respectively. The colonic side-to-side anastomosis was completed in all 24 rats, and the operation success rate and postoperative survival rate were 100%. No significant difference was noted in the operation time between the two groups. The magnet discharge time of the powerful magnet group was slightly longer than that of the common magnet group, but the difference was not statistically significant (P = 0.513). Furthermore, there was no statistical difference in the burst pressure (P = 0.266) or diameter of magnetic anastomosis (P = 0.095) between the two groups. The gross specimens of the two groups showed good anastomotic healing, and histological observation indicated good mucosal continuity without differences on healing.

CONCLUSION

In the rat colonic side-to-side MCA model, both the powerful magnet with 8.26 N and the common magnet with 4.10 N showed no significant impact on the anastomosis establishment process or its effect.

Application of Y-Z deformable magnetic ring for recanalization of transanal single-access rectal stricture

Magnetic compression anastomosis has been reported to have remarkable clinical outcomes. Here, we tested the applicability of a Y-Z deformable magnetic ring (DMR) for non-surgical manipulation of rectal stenosis (RS) in a beagle dog model under a transanal single-access condition. RS was modeled in 8 beagle dogs using partial ligation with silk thread. Under X-ray guidance, the Y-Z DMR was positioned at the proximal and distal ends of the RS, and the magnetic ring was bent into an "O" shape, such that the two rings were magnetically attracted. Operation time, complications during or after operation, and discharge time of the magnetic rings were recorded. The anastomosis bursting pressure was measured two weeks after removing the rings, and its formation was assessed through gross and histological examination. Partial ligation with a silk thread successfully established the canine RS model. After Y-Z DMR installation, the magnetic ring was successfully reconfigured from an "S" to an "O" shape. Strong attraction existed between the rings. The operation time was 9-15 min (average: 11.75 ± 1.98 min). No rectal bleeding or perforation occurred during or after operation. The ring was naturally expelled 7-10 days after surgery. A pressure of > 300 mmHg was recorded at the point of anastomosis rupture. The rectal anastomosis appeared to have healed properly on the surface, which was confirmed histologically, signifying the success of this procedure. A Y-Z DMR facilitated the successful recanalization of transanal single-channel RS without needing surgery in an animal model.

Clinical application of magnetic anchor technique in laparoscopic cholecystectomy: the first retrospective study in China

Background and objectives

Magnetic anchor technique (MAT) is frequently used in laparoscopic cholecystectomy. However, there are few reports on its clinical application in China. In this study, we retrospectively analyzed the clinical application of MAT in laparoscopic cholecystectomy in China.

Materials and methods

25 patients (4 males, 21 females) who underwent laparoscopic cholecystectomy assisted by MAT at the First Affiliated Hospital of Xi'an Jiaotong University were enrolled from November 2020 to March 2021. Their records were retrospectively analyzed. The magnetic anchor device was independently designed and developed by the authors and consisted of the anchor magnet and magnetic grasping apparatus. Surgical time, intraoperative blood loss, intraoperative accidents, operator experience, postoperative incision pain score, postoperative complications, and other indicators were evaluated and analyzed.

Results

All patients successfully underwent laparoscopic cholecystectomy, including 3 cases of MAT-assisted transumbilical single-port LC, 16 cases of MAT-assisted 2-port LC and 6 cases of conventional 3-port LC. The median operation time was 50 min (range 30-95 min); intraoperative bleeding was less than 30 ml. The median score of surgical incision on day 1 and 3 after the operation was 3 (range 1-4) and 1 (range 1-3), respectively. All patients had no intraoperative bile duct injury, vascular injury, postoperative bleeding, bile leakage, biliary stricture and other complications. No adverse events (such as injury to adjacent organs or failure of the magnetic anchor device) occurred either during or after the operation.

Conclusions

The MAT-assisted laparoscopic cholecystectomy appears to be safe, feasible and effective and exhibits unique assistance in transumbilical single-port laparoscopic cholecystectomy.

First-in-Human Side-to-Side Magnetic Compression Duodeno-ileostomy with the Magnet Anastomosis System

PURPOSES

Classical gastrointestinal anastomoses are formed with sutures and/or metal staples, resulting in significant bleeding and leak rates. This study evaluated the feasibility and safety of the novel magnet anastomosis system (MS) to create a side-to-side duodeno-ileal (DI) diversion for weight loss and type 2 diabetes (T2D) resolution.

MATERIALS AND METHODS

Patients with severe obesity (body mass index (BMI) ≥ 35 kg/m2 with/without T2D (HbA1C ≥ 6.5%)) underwent the study procedure, a side-to-side MS DI diversion, with a standard sleeve gastrectomy (SG). A linear magnet was delivered by flexible endoscopy to a point 250 cm proximal to the ileocecal valve; a second magnet was positioned in the first part of the duodenum; the bowel segments containing magnets were apposed, initiating gradual anastomosis formation. Laparoscopic assistance was used to obtain bowel measurements, obviate tissue interposition, and close mesenteric defects.

RESULTS

Between November 22 and 26, 2021, 5 female patients (mean weight 117.6 ± 7.1 kg, BMI (kg/m2) 44.4 ± 2.2) underwent side-to-side MS DI + SG. All magnets were successfully placed, expelled without re-intervention, and formed patent durable anastomoses. Total weight loss at 12 months was 34.0 ± 1.4% (SEM); excess weight loss, 80.2 ± 6.6%; and BMI reduction, 15.1. Mean HbA1C (%) dropped from 6.8 ± 0.8 to 4.8 ± 0.2; and glucose (mg/dL), from 134.3 ± 17.9 to 87.3 ± 6.3 (mean reduction, 47.0 mg/dL). There was no anastomotic bleeding, leakage, obstruction, or infection and no mortality.

CONCLUSIONS

Creation of a side-to-side magnetic compression anastomosis to achieve duodeno-ileostomy diversion in adults with severe obesity was feasible and safe, achieved excellent weight loss, and resolved type 2 diabetes at 1-year follow-up.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT05322122.

Primary animal experiment to test the feasibility of a novel Y-Z magnetic hepatic portal blocking band

BACKGROUND

Hepatic portal blood flow occlusion is a common technique for reducing hepatic hemorrhage during hepatectomy. We designed a novel Y-Z magnetic hepatic portal blocking band (Y-Z MHPBB) based on the principle of magnetic compression technique.

AIM

To introduce the Y-Z MHPBB device and verify the feasibility of this device for hepatic portal blood flow occlusion in dogs.

METHODS

Ten beagles were randomly divided into the experimental group and control group. The operation time, intraoperative blood loss, the number of portal blood flow occlusions, the total time spent on adjusting the blocking band, and the average time spent on adjusting the blocking band were recorded. The surgeons evaluated the feasibility and flexibility of the two portal occlusion devices.

RESULTS

Laparoscopic hepatectomy was successfully performed in both the experimental group and control group. There was no statistical difference between the two groups in the operation time, intraoperative blood loss, and the number of hepatic portal blood flow occlusions. With respect to the total time spent on adjusting the blocking band and the average time spent on adjusting the blocking band, the experimental group showed significantly better outcomes than the control group, with a statistical difference (P < 0.05). The operators found that the Y-Z MHPBB was superior to the modified T-tube in terms of operational flexibility.

CONCLUSION

The Y-Z MHPBB seems to be an ingenious design, accurate blood flow occlusion effect, and good flexibility; and it can be used for hepatic portal blood flow occlusion during laparoscopic hepatectomy.

Biologically inspired gastrointestinal stapler design: "Getting to Zero" complications

As next generation stapling devices enter the marketplace with robotic adaptations, tri-staple technology, preloaded reinforcement materials, etc., in this perspective piece we assert that a "refresh" in our understanding of the mechanisms of action of these devices is needed. While much attention has been paid to explain the mechanical features of one device versus another, it seems that little to no attention is being paid to understand how an intestinal anastomosis responds biologically to the variations in their use and design. Here we will review various aspects of gastrointestinal stapling in the context of emerging technology in the field and expose the gaps in knowledge that exist regarding the effect of gastrointestinal stapling on the biology of healing.

Side-to-side duodeno-ileal magnetic compression anastomosis: design and feasibility of a novel device in a porcine model

BACKGROUND

Minimally invasive metabolic/bariatric surgery (MBS) may be further advanced by magnetic compression anastomosis (MCA) technology. The study aimed to develop a magnet sized to create a patent duodeno-ileostomy (DI) and verify its effectiveness in a porcine model.

METHODS

Developmental study phase: magnets with 4 different flange-offset dimensions were tested to identify a design that would successfully form a compression anastomosis. Verification phase: evaluation of the selected design's efficacy. In each 6-week phase (4 pigs/phase), one magnet was inserted laparoscopically in the jejunum, one placed gastroscopically in the duodenum. Magnets were aligned, gradually fused, formed an anastomosis, and then detached and were expelled. At necropsy, MCA sites and sutured enterotomy sites were collected and compared.

RESULTS

Developmental phase: the linear BC42 magnet with a 2.3-mm flange offset design was selected. Verification phase: in 4 swine magnets were mated at the target location, confirmed radiographically. Mean time to magnet detachment 16.0 days (12-22), to expulsion 24.5 days (17-33). MCA was achieved in all animals at time of sacrifice. Animals gained a mean 9.5 kg (3.9-11.8). Specimens revealed patent anastomoses of ≥ 20 mm with smooth mucosa and minimal inflammation and fibrosis compared to sutured enterotomies. One pig underwent corrective surgery for a mesenteric hernia without sequelae.

CONCLUSION

In a large-animal model, gross and histopathologic examination confirmed that the linear MCA device created a patent, well-vascularized, duodeno-ileal anastomosis. The novel MCA device may be appropriate for use in human MBS procedures.

Comparative early histologic healing quality of magnetic versus stapled small bowel anastomosis

BACKGROUND

Successful anastomotic healing is critical to preventing complications after intestinal surgery. We aimed to compare the early healing of end-to-end small bowel anastomosis by self-forming magnets with surgical stapling in a porcine model.

METHOD

Six Yorkshire pigs underwent 2 simultaneous small bowel anastomoses using a circular stapler and self-forming magnet technique. The primary outcome was healing quality, measured by 4 histologic features: inflammatory cell infiltration, collagen formation, grade of inflammation, and bacterial infiltration at the anastomosis. The samples were evaluated at days 1, 3, and 7. Gross evaluation of anastomotic integrity was a secondary outcome.

RESULTS

The self-forming magnet group displayed significant differences at each time point. On day 1, the stapled group displayed dense inflammatory cell infiltration and extensively ulcerated intestinal layers with significant edema. The self-forming magnet group showed less inflammatory infiltrate, and all intestinal layers remained compressed in direct apposition. By day 3, the self-forming magnet group already exhibited neovascularization with scant bacterial colonies. By contrast, stapled anastomoses had large areas of inflammation separating collagen fibers with prevalent bacterial infiltrations. On day 7, self-forming magnet anastomoses were characterized by robust neovascularization, maturing granulation tissue, and mucosal re-epithelization without significant inflammation. Meanwhile, stapled samples had persisting dense inflammation, tissue cavities with hemorrhage, and immature fibrous tissue. Grossly, the self-forming magnet created a patent lumen without defect, whereas stapled anastomoses demonstrated focal areas of serosal separation.

CONCLUSION

Bowel anastomosis by self-forming magnets is associated with superior early histologic healing metrics, including early seal generation through mechanical compression, decreased inflammation, early neovascularization, lower bacterial infiltration, and faster re-epithelization.

The Evolving Use of Magnets in Surgery: Biomedical Considerations and a Review of Their Current Applications

The novel use of magnetic force to optimize modern surgical techniques originated in the 1970s. Since then, magnets have been utilized as an adjunct or alternative to a wide array of existing surgical procedures, ranging from gastrointestinal to vascular surgery. As the use of magnets in surgery continues to grow, the body of knowledge on magnetic surgical devices from preclinical development to clinical implementation has expanded significantly; however, the current magnetic surgical devices can be organized based on their core function: serving as a guidance system, creating a new connection, recreating a physiologic function, or utilization of an internal–external paired magnet system. The purpose of this article is to discuss the biomedical considerations during magnetic device development and review the current surgical applications of magnetic devices.