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

Comparative study on the establishment efficacy of four types of animal models of rectovaginal fistula in rabbits

Various surgical methods have so far been developed for treating rectovaginal fistula (RVF), each with its own advantages and disadvantages. The lack of standardized animal models of RVF is a major reason for the failure to establish a unified and effective surgical method for the treatment of RVF. This study aimed to explore the feasibility of an RVF animal model by magnetic compression and compare it with the traditional modeling method. Thirty-two female Japanese white rabbits were randomly divided into four groups: A, B, C, and D, based on how the rectovaginal septum was treated. The operation time, intraoperative blood loss, and model success rate of each group were determined. The experimental animals were euthanized 2 weeks after the operation. Their rectovaginal septum specimens were obtained. RVF was observed by the naked eye. The fistula size was measured. Histological changes of fistula were observed by hematoxylin and eosin and Masson staining. All rabbits completed the RVF model and survived 2 weeks after the operation. Groups A and B had no bleeding, while groups C and D had < 0.5 mL of bleeding. The magnet detached in 4-6 days in group A, while it remained in place for 2 weeks after surgery in group B. Only one group D rabbit had a plastic hose for 2 weeks after surgery. The RVFs of groups A and C healed by themselves. In group B, the fistula was well formed. In group D, fistula healing was observed in three animals and the diameter of the fistulas was only 2.82-4.64 mm in the other four animals. Groups B and D had a scar on the inner surface of fistulas. Our study shows that the magnetic compression technique based on the T-shaped magnet is a highly useful method to establishing a continuous and stable RVF model in rabbits.

Sleeve gastrectomy with duodenoileal bipartition using linear magnets: feasibility and safety at 1-year follow-up

BACKGROUND

Single-anastomosis metabolic/bariatric surgery procedures may lessen the incidence of anastomotic complications. This study aimed to evaluate the feasibility and safety of performing side-to-side duodenoileal (DI) bipartition using magnetic compression anastomosis (MCA). In addition, preliminary efficacy, quality of life (QoL), and distribution of food through the DI bipartition were evaluated.

METHODS

Patients with a body mass index (BMI) of ≥35.0 to 50.0 kg/m2 underwent side-to-side DI bipartition with the magnet anastomosis system (MS) with sleeve gastrectomy (SG). By endoscopic positioning, a distal magnet (250 cm proximal to the ileocecal valve) and a proximal magnet (first part of the duodenum) were aligned with laparoscopic assistance to inaugurate MCA. An isotopic study assessed transit through the bipartition.

RESULTS

Between March 14, 2022 to June 1, 2022, 10 patients (BMI of 44.2 ± 1.3 kg/m2) underwent side-to-side MS DI. In 9 of 10 patients, an SG was performed concurrently. The median operative time was 161.0 minutes (IQR, 108.0-236.0), and the median hospital stay was 3 days (IQR, 2-40). Paired magnets were expelled at a median of 43 days (IQR, 21-87). There was no device-related serious advanced event within 1 year. All anastomoses were patent with satisfactory diameters after magnet expulsion and at 1 year. Respective BMI, BMI reduction, and total weight loss were 28.9 ± 1.8 kg/m2, 15.2 ± 1.8 kg/m2, and 34.2% ± 4.1%, respectively. Of note, 70.0% of patients reported that they were very satisfied. The isotopic study found a median of 19.0% of the meal transited through the ileal loop.

CONCLUSION

Side-to-side MCA DI bipartition with SG in adults with class II to III obesity was feasible, safe, and efficient with good QoL at 1-year follow-up. Moreover, 19% of ingested food passed directly into the ileum.

Optimization of tracheoesophageal fistula model established with T-shaped magnet system based on magnetic compression technique

BACKGROUND

The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments.

AIM

To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs.

METHODS

Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining.

RESULTS

The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group.

CONCLUSION

Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.

Side-to-side magnetic duodeno-ileostomy in adults with severe obesity with or without type 2 diabetes: early outcomes with prior or concurrent sleeve gastrectomy

BACKGROUND

Conventional metabolic/bariatric surgical anastomoses with sutures/staples may cause severe adverse events (AEs).

OBJECTIVES

The study aim was to evaluate the feasibility, safety, and effectiveness of primary and revisional side-to-side duodeno-ileostomy (DI) bipartition using a novel magnetic compression anastomosis device (Magnet Anastomosis System [MS]).

SETTING

Multicenter: private practices and university hospitals.

METHODS

In patients with body mass index ([BMI, kg/m2] ≥35.0 to ≤50.0 with/without type 2 diabetes [T2D] glycosylated hemoglobin [HbA1C > 6.5 %]), two linear MS magnets were delivered endoscopically to the duodenum and ileum with laparoscopic assistance and aligned, initiating magnet fusion and gradual DI (MagDI). The MagDI-after-SG group had undergone prior sleeve gastrectomy (SG); the MagDI + SG group underwent concurrent SG. AEs were graded by Clavien-Dindo Classification (CDC).

RESULTS

Between November 22, 2021 and May 30, 2023, 43 patients (88.0% female, mean age 43.7 ± 1.3 years) underwent the study procedures. The MS met feasibility criteria of magnet device placement, creation of patent anastomoses confirmed radiologically, and magnet passage in 100.0% of patients. There were 64 AEs, most were CDC grade I and II, significantly fewer in the MagDI-after-SG group (P < .001). No device-related AEs including anastomotic leakage, bleeding, obstruction, infection, or death. The MagDI-after-SG group experienced 6-month mean weight loss of 8.0 ± 2.5 kg (P < .01), 17.4 ± 5.0% excess weight loss (EWL). The MagDI + SG group had significantly greater weight loss (34.2 ± 1.6 kg, P < .001), 66.2 ± 3.4% EWL. All patients with T2D improved.

CONCLUSIONS

In early results of a multicenter study, the incisionless, sutureless Magnet System formed patent, complication-free anastomoses in side-to-side DI with prior or concurrent SG.

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.

Y-Z deformable magnetic ring for the treatment of rectal stricture: A case report and review of literature

BACKGROUND

Treatment of postoperative anastomotic stenosis for colorectal cancer is often challenging, especially for patients who do not respond well to endoscopy. In cases where patients have undergone an enterostomy, the stenosis can be easily resolved through magnetic compression. However, common magnetic compression techniques cannot be performed on those without enterostomy. We designed a novel Y-Z deformable magnetic ring (Y-Z DMR) and successfully applied it to a patient with a stenosis rectal anastomosis and without enterostomy after rectal cancer surgery.

CASE SUMMARY

We here report the case of a 57-year-old woman who had undergone a laparoscopic radical rectum resection (Dixon) for rectal cancer. However, she started facing difficulty in defecation 6 months after surgery. Her colonoscopy indicated stenosis of the rectal anastomosis. Endoscopic balloon dilation was performed six times on her. However, the stenosis still showed a trend of gradual aggravation. Because the patient did not undergo an enterostomy, the conventional endoscopic magnetic compression technique could not be performed. Hence, we implemented a Y-Z DMR implemented through the anus under single channel. The magnetic ring fell off nine days after the operation and the rectal stenosis was relieved. The patient was followed up for six months and reported good defecation.

CONCLUSION

The Y-Z DMR deformable magnetic ring is an excellent treatment strategy for patients with rectal stenosis and without enterostomy.

Evaluation of a Magnetic Compression Anastomosis for Jejunoileal Partial Diversion in Rhesus Macaques

PURPOSE

Metabolic surgery remains underutilized for treating type 2 diabetes, as less invasive alternative interventions with improved risk profiles are needed. We conducted a pilot study to evaluate the feasibility of a novel magnetic compression device to create a patent limited caliber side-to-side jejunoileal partial diversion in a nonhuman primate model.

MATERIALS AND METHODS

Using an established nonhuman primate model of diet-induced insulin resistance, a magnetic compression device was used to create a side-to-side jejunoileal anastomosis. Primary outcomes evaluated feasibility (e.g., device mating and anastomosis patency) and safety (e.g., device-related complications). Secondary outcomes evaluated the device's ability to produce metabolic changes associated with jejunoileal partial diversion (e.g., homeostatic model assessment of insulin resistance [HOMA-IR] and body weight).

RESULTS

Device mating, spontaneous detachment, and excretion occurred in all animals (n = 5). There were no device-related adverse events. Upon completion of the study, ex vivo anastomoses were widely patent with healthy mucosa and no evidence of stricture. At 6 weeks post-device placement, HOMA-IR improved to below baseline values (p < 0.05). Total weight also decreased in a linear fashion (R2 = 0.97) with total weight loss at 6 weeks post-device placement of 14.4% (p < 0.05).

CONCLUSION

The use of this novel magnetic compression device to create a limited caliber side-to-side jejunoileal anastomosis is safe and likely feasible in a nonhuman primate model. The observed glucoregulatory and metabolic effects of a partial jejunoileal bypass with this device warrant further investigation to validate the long-term glucometabolic impact of this approach.

Endoscopic gastrointestinal bypass anastomosis using deformable self-assembled magnetic anastomosis rings (DSAMARs) in a pig model

BACKGROUND

To investigate the feasibility of a deformable self-assembled magnetic anastomosis ring (DSAMAR), designed and developed by us, for endoscopic gastrointestinal bypass anastomosis.

METHODS

Ten experimental pigs were used as model animals. The DSAMAR comprises 10 trapezoidal magnetic units, arranged in a straight line under the constraint of a guide wire. When the desired anastomosis site is reached under the guidance of an endoscope, the catheter pushes the magnetic unit along the guide wire. The linear DSAMAR can be assembled into a circular DSAMAR. Two DSAMARs were inserted, one at the end of the duodenum and the other into the stomach successively. They attracted each other and compressed the wall of the stomach and duodenum to establish gastrointestinal bypass anastomosis. The experimental pigs were euthanized 4 weeks after the operation, and the gastrointestinal bypass anastomosis specimens were obtained. The anastomosis formation was evaluated by the naked eye and histology.

RESULTS

Gastrointestinal bypass anastomosis with DSAMARs was successfully performed. The average operation time under an endoscope was 70.30 ± 19.05 min (range: 43-95 min). The DSAMARs were discharged through the anus 10-17 days after surgery. There were no complications such as gastrointestinal bleeding, perforation, anastomotic fistula, and gastrointestinal obstruction during and after the operation. Gastroscopy and gross specimen of the anastomosis showed a well-formed magnetic anastomosis. Histological observation showed good continuity of the serous membrane and the mucosa of magnetic anastomosis.

CONCLUSION

The DSAMAR is a safe and feasible device for fashioning gastrointestinal bypass anastomosis in this animal model.

Magnetic Compression Anastomosis-Past Experience and Current Proposals for Further Development in Pediatric Minimally Invasive Surgery

Originating in the 1970s, magnetic compression anastomosis (MCA) has lately been revisited with a focus on minimal invasive surgery (MIS). The aim of this report is to reappraise our earlier experience with MCA with the intention of facilitating future MCA advancement. A retrospective review was conducted regarding preclinical experiments and clinical trials at a single institution from 1980 to 1995. The reviewed information was compiled and appraised to generate proposals for future MCA use. The experimental studies, including 250 MCA cases in gastrointestinal and urinary tract animal models, demonstrated the technical versatility of MCA as well as the superior biomechanical characteristics in comparison to hand-sewn anastomoses. Clinical trials encompassed 87 MCA procedures in 86 children, 2 to 10 years of age, involving the following techniques: non-operative esophageal recanalization (n = 15), non-operative ileostomy undiversion (n = 46), Swenson pull-through (n = 10), non-operative urethral recanalization (n = 5), and extravesical ureterocystoneostomy (n = 11). Clinical MCA was found to be successful in over 87% of cases. MCA limitations concerning anastomotic failure and scarring were thought to be mostly due to inadequate magnetic compression. Based on our historic experience, we propose further research on the technical aspects of MCA, along with the biological aspects of anastomotic tissue remodeling. Magnets should be designed and manufactured for a wide spectrum of pediatric surgical indications, particularly in combination with novel MIS techniques.