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.

Magnetic Compression Anastomosis (Magnamosis) for Functional Undiversion of Ileostomy in Pediatric Patients.

INTRODUCTION: Magnamosis forms a compression anastomosis using self-aligning magnetic Harrison rings. The device has been approved by the Food and Drug Administration for first-in-human testing and has been applied in adults for intestinal anastomosis during urologic reconstructions. We now report the first cases of magnamosis to functionally undivert the fecal stream from a previously created loop ileostomy in pediatric patients. MATERIALS AND METHODS: Case 1: A 4-year-old male underwent a diverting loop ileostomy for malignant bowel obstruction. The obstruction gradually resolved with chemotherapy, and persistently high stomal output and malnutrition prompted undiversion. Case 2: A 16-year-old female with iloecolonic polyposis underwent ileoproctectomy with J pouch and diverting ileostomy. The magnamosis functional undiversion (FUN) technique involves introducing a Harrison ring through each stomal limb under general anesthesia with X-ray guidance. Magnets are each tied with sutures that exit the stoma and are then tied to each other externally. The device is removed when patency is detected. RESULTS: The introduction procedure took less than 20 minutes and there were no complications. Enteral feeding was initiated 24 and 6 hours postoperatively, and distal passage of stool occurred by the fourth and fifth days, respectively. Magnets were removed 14 and 15 days postoperatively, without evidence of leak. CONCLUSION: We conclude that the magnamosis undiversion procedure is a safe, minimally invasive way to gradually refunctionalize the excluded distal bowel after previous diverting ostomy.

Magnetic Compression Anastomosis (Magnamosis): First-In-Human Trial.

BACKGROUND: Magnetic compression anastomosis (magnamosis) uses a pair of self-centering magnetic Harrison Rings to create an intestinal anastomosis without sutures or staples. We report the first-in-human case series using this unique device. STUDY DESIGN: We conducted a prospective, single-center, first-in-human pilot trial to evaluate the feasibility and safety of creating an intestinal anastomosis using the Magnamosis device. Adult patients requiring any intestinal anastomosis to restore bowel continuity were eligible for inclusion. For each procedure, 1 Harrison Ring was placed in the lumen of each intestinal segment. The rings were brought together and mated, and left to form a side to side, functional end to end anastomosis. Device movement was monitored with serial x-rays until it was passed in the stool. Patients were monitored for adverse effects with routine clinic appointments, as well as questionnaires. RESULTS: Five patients have undergone small bowel anastomosis with the Magnamosis device. All 5 patients had severe systemic disease and underwent complex open urinary reconstruction procedures, with the device used to restore small bowel continuity after isolation of an ileal segment. All devices passed without obstruction or pain. No patients have had any complications related to their anastomosis, including anastomotic leaks, bleeding, or stricture at median follow-up of 13 months. CONCLUSIONS: In this initial case series from the first-in-human trial of the Magnamosis device, the device was successfully placed and effectively formed a side to side, functional end to end small bowel anastomosis in all 5 patients. No patients have had any anastomotic complications at intermediate follow-up.

Magnetic Mini-Mover Procedure for pectus excavatum IV: FDA sponsored multicenter trial.

PURPOSE: The Magnetic Mini-Mover Procedure (3MP) is a minimally invasive treatment for prepubertal patients with pectus excavatum. This multicenter trial sought to supplement safety and efficacy data from an earlier pilot trial. METHODS: Fifteen patients with pectus excavatum had a titanium-enclosed magnet implanted on the sternum. Externally, patients wore a custom-fitted magnetic brace. Patients were monitored closely for safety. Efficacy was determined by the Haller Index (HI) and satisfaction surveys. After 2 years, the implant was removed. RESULTS: Mean patient age was 12 years (range 8-14), and mean pretreatment HI was 4.7 (range 3.6-7.4). The device was successfully implanted in all patients. Mean treatment duration was 25 months (range 18-33). Posttreatment chest imaging in 13 patients indicated that HI decreased in 5, remained stable in 2, and increased in 6. Seven out of 15 patients had breakage of the implant's titanium cables because of fatigue fracture. Eight out of 13 patients were satisfied with their chest after treatment. CONCLUSION: The 3MP is a safe, minimally invasive, outpatient treatment for prepubertal patients with pectus excavatum. However, the magnetic implant design led to frequent device breakage, confounding analysis. The HI indicated mixed efficacy, although surveys indicated most patients perceived a benefit. STUDY TYPE/LEVEL OF EVIDENCE: Case series, treatment study. Level IV.

MyPectus: First-in-human pilot study of remote compliance monitoring of teens using dynamic compression bracing to correct pectus carinatum.

BACKGROUND: Patient compliance is a crucial determinant of outcomes in treatments involving medical braces, such as dynamic compression therapy for pectus carinatum (PC). We performed a pilot study to assess a novel, wireless, real-time monitoring system (MyPectus) to address noncompliance. METHODS: Eight patients (10-16years old) with moderately severe PC deformities underwent bracing. Each patient received a data logger device inserted in the compression brace to sense temperature and pressure. The data were transmitted via Bluetooth 4.0 to an iOS smartphone app, then synced to cloud-based storage, and presented to the clinician on a web-based dashboard. Patients received points for brace usage on the app throughout the 4-week study, and completed a survey to capture patient-reported usage patterns. RESULTS: In all 8 patients, the data logger sensed and recorded data, which connected through all MyPectus system components. There were occasional lapses in data collection because of technical difficulties, such as limited storage capacity. Patients reported positive feedback regarding points. CONCLUSIONS: The components of the MyPectus system recorded, stored, and provided data to patients and clinicians. The MyPectus system will inform clinicians about issues related to noncompliance: discrepancy between patient-reported and sensor-reported data regarding brace usage; real-time, actionable information; and patient motivation.

Geometry of Proximal Humerus Locking Plates.

OBJECTIVES: Proximal humerus fractures are commonly treated with open reduction and internal fixation with periarticular locking plates. This study compared the geometry of proximal humerus locking plate's screw distribution, amount of bone-screw interface, and the volume the screws occupy within the humeral head, as well as how leaving the screws short of the articular surface affects these measures. METHODS: Locking plates from 7 manufacturers were applied to foam humerus models. The entry and exit hole of each screw trajectory was digitized using a 3-dimensional motion tracking system. A trajectory for each screw was modeled, as well as the volume enclosed by the screw trajectories. The following outcome metrics were calculated: the bone-screw interface, the volume enclosed by the screws, and the effect of leaving the screws short of the articular surface. RESULTS: Biomet had the most bone-screw interface (7259 mm), whereas Zimmer had the least (3982 mm). The original Synthes plate had the largest screw volume, occupying 31.5% of the humeral head, whereas Smith & Nephew and Zimmer had the lowest volumes, occupying 21.2% and 12.6%, respectively. Leaving the screws 15 mm short of the articular surface resulted in the most reduction in volume for the Depuy plate (50%) and the least reduction for the new version of the Synthes plate (29%). CONCLUSIONS: Many different manufactured periarticular locking plates exist to stabilize a proximal humeral fracture. Clinicians need to be familiar with the different plate configurations, screw lengths, and trajectories, which affect potential biomechanical performance and can optimize fracture site maintenance.

Miniaturizing RFID for magnamosis.

Anastomosis is a common surgical procedure using staples or sutures in an open or laparoscopic surgery. A more effective and much less invasive alternative is to apply the mechanical pressure on the tissue over a few days [1]. Since the pressure is produced by the attractive force between two permanent magnets, the procedure is called magnamosis[1]. To ensure the two magnets are perfectly aligned during the surgery, a miniaturized batteryless Radio Frequency IDentification (RFID) tag is developed to wirelessly telemeter the status of a pressure sensitive mechanical switch. Using the multi-layer circular spiral coil design, the diameter of the RFID tag is shrunk to 10, 15, 19 and 27 mm to support the magnamosis for children as well as adults. With the impedance matching network, the operating distance of these four RFID tags are longer than 10 cm in a 20 × 22 cm(2) area, even when the tag's normal direction is 45° off the antenna's normal direction. Measurement results also indicate that there is no noticeable degradation on the operating distance when the tag is immersed in saline or placed next to the rare-earth magnet. The miniaturized RFID tag presented in this paper is able to support the magnamosis and other medical applications that require the miniaturized RFID tag.

Magnamosis III: delivery of a magnetic compression anastomosis device using minimally invasive endoscopic techniques.

PURPOSE: Magnamosis creates a secure sutureless anastomosis through magnetic compression. In this study, we further develop and test delivery devices capable of creating a secure duodeno-colonic anastomosis using available minimally invasive endoscopic techniques. METHODS: Eight pigs underwent general anesthesia. Colonoscopy was used to deliver 1 magnetic ring to the hepatic flexure. Simultaneously, upper endoscopy delivered the other magnetic ring into the duodenum using a variety of techniques. The 2 magnetic rings were brought into magnetic proximity under laparoscopic guidance. The pigs were recovered and examined daily followed by sacrificing at 1, 2, 4, and 6 weeks. RESULTS: The device designed to deliver and release each magnetic ring evolved from using a guide wire and balloon devices to redesigning the magnetic ring casing with a groove to accommodate an endoscopic snare. Laparoscopic visualization assured safe magnet mating of intestinal segments. The duodeno-colonic anastomoses created with the snare yielded widely patent anastomoses. In vitro testing revealed excellent burst pressure. Histology revealed complete healing as early as 1 week. CONCLUSION: We redesigned the magnamosis device to facilitate delivery by endoscopic techniques. The snare technique allows endoscopic positioning and controlled release of the magnetic rings for a secure side-to-side duodeno-colonic anastomosis.

Hyoid bone advancement for improving airway patency: cadaver study of a magnet-based system.

OBJECTIVE: The goal of this study was to evaluate the effect of anterior forces applied to the hyoid bone on upper airway dimensions and airflow. The study also evaluated the feasibility of applying these forces using a novel magnet-based system. STUDY DESIGN: Human cadaver specimens. SETTING: Surgical laboratory. SUBJECTS AND METHODS: Five fresh cadaveric specimens were evaluated using fluoroscopy and computed tomography to examine upper airway opening as well as an airflow model to examine upper airway collapse. Anteriorly directed force was applied to the hyoid bone directly using a wire and with a magnet-based system called the Magnap device. Direct application of force was examined with an axial load frame or suspended weights. The magnet-based system applied similar forces using an internal, implanted magnet secured to the hyoid bone and an external magnet housed within an orthotic brace. RESULTS: A force of 2 N perpendicular to the neck skin advanced the hyoid 1 cm, opened the upper airway, and significantly improved airflow. The implanted magnet-based device generated similar forces, with similar effects on the upper airway. CONCLUSION: Application of anterior force to the hyoid bone improved upper airway dimensions and airflow in the human cadaver model. These results justify additional study to evaluate the benefits of this magnet-based system as a possible treatment of upper airway obstruction.