Dillon Kwiat

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.

ROBOImplant II: Development of a Noninvasive Controller/Actuator for Wireless Correction of Orthopedic Structural Deformities

An implantable actuator and its accompanying driver circuit are presented for the purpose of lengthening bones and correcting skeletal deformities without requiring physical contact between the operator and the implanted device. This system utilizes magnetic coupling to form a magnetic gear, allowing an external motor to drive an implantable telescoping rod. The accompanying electronics are able to monitor the progress, in the form of turns delivered, as well as detect procedural errors, such as magnet decoupling. The force applied by the implanted telescoping rod can be accurately measured by monitoring the current necessary for the external controller to drive the extension of the implanted rod. After characterization, the system was shown to reliably deliver extension distances within 34 μm and maintain coupling out to 70 mm. The system is also able to measure torques as low as 0.12 mN m. System variability and accuracy of external monitoring are addressed.

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.

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.

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 implants 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.

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 cm2 area, even when the tags normal direction is 45° off the antennas 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.

Review of existing brace adherence monitoring methods to assess adherence

Introduction Outcomes of therapeutic orthopedic brace treatments are highly dependent on adherence. Medical brace adherence studies over several years have noted the poor adherence rates among many orthopedic and orthodontic medical braces. Lack of adherence has been demonstrated in many studies to lead to unsatisfactory results. With decreased adherence, desired therapeutic effects are difficult, if not impossible to achieve, regardless of the ability of the clinical intervention. Nonadherence also burdens the health care system with preventable costs due to disease progression and the necessity for increased intervention. The problem is also compounded by the inability to reliably measure adherence rates among brace wearers. In addition, no current review of the adherence monitoring systems used in orthotic braces exists. Materials and Methods Searches were conducted on PubMed and Cochrane databases using the following terms individually or in combination: adherence, compliance, remote monitoring, brace treatment, scoliosis, mini magnetic mover 3MP, Pectus Excavatum, fitness trackers, activity trackers, FitBit, JawBone, and Nike FuelBand. In addition, references found in these articles were reviewed and used if applicable. The goal was to assess brace adherence monitoring platforms across different age groups and disease states. Because many of the modalities used to quantify adherence arose after the year 2000, we focused on this year range due to availability of better sensors and data validation. From this method, articles on adherence rates and monitoring systems in scoliosis, clubfoot, ankle, and knee immobilizer bracings were reviewed to analyze the low adherence. Commercial fitness trackers were assessed for their ability to monitor daily fitness metrics and use goal setting as a way to bolster adherence in relation to medical brace monitoring. Results Adherence among all medical braces is remarkably low, leading to further disease progression and increased interventions and health expenditures. Orthodontic headgear has adherence rates at 56.7%. Clubfoot braces have a nonadherence rate ranging from 30% to 41%. Scoliosis braces have similar nonadherence rates ranging from 27% to 45%. In one study, a third of scoliosis patients only wore their brace for less than 2 hrs/d, and of this group, 44% of them needed surgical measures for spinal correction. However, much of these data comes from self-reported adherence. Studies comparing sensor-based and self-reported adherence highlighted a possible discrepancy between the two. In clubfoot bracing, the adherence data for the first 3 months were statistically different between the pressure-based sensor and the self-reported values (P < 0.0001). An analysis on scoliosis bracing adherence showed that there was no statistically significant discrepancy (P = 0.000) between self-reported and sensor-based adherence. This disconnect indicates that patients and caregivers may not be reliable historians. All the adherence tracking systems in these articles required data downloads at clinic visits, and none used real-time monitoring for adherence measurement. Moreover, when individuals knew they were being monitored for adherence, their wear rate with scoliosis bracing increased (85.7% vs. 56.5%, P = 0.029). Fitness trackers have also been shown to be able to increase amount of physical activity by 4.3 min/wk and number of daily steps by 800 to 1266 steps/d through self-monitoring and engagement strategies. The combination of real-time tracking with patient goal setting can create a platform for clinicians to intervene earlier and may have a role in improving adherence. Conclusions Real-time monitoring is the next direction for medical device adherence. It can help close the gap between self-reported and actual adherence data, while facilitating a more therapeutic outcome with the ability to intervene with earlier health interventions from the care team. Because we currently do not have a robust system in place to quantify adherence, a real-time monitoring platform can pave the way as a method to help gather accurate adherence data and help validate new medical braces entering the field of orthotics. An approach of remote adherence monitoring system can be applied to brace systems as a platform for an early intervention in case of nonadherence and provide real-time monitoring data accessible to both patient and physician for individualized goal setting, possibly facilitating an increase in adherence.

Inductive Sensing to Detect Tissue Thickness Between Magnets for Potential Application in Magnetic Compression Based Anastomosis

Magnetic compression based anastomoses use magnetic force to necrose tissue between two magnets to create an anastomosis. Nickel-plated neodymium–iron–boron magnets are used in our study. The compression pressure between the magnets depends on the distance between the magnets, which is determined by the thickness of the compressed tissue and depends on bowel wall thickness and elasticity. It is critical to know the distance between the magnets once the tissue is compressed because the magnets must be within a critical distance of each other in order to create enough compressive force to necrose the tissue. We have developed an inductance sensor to detect the distance (tissue thickness) between the two magnets after the surgeon has deployed them. Inductance sensing is a contact-less sensing method that enables precise short-range detection of conducting surfaces. The inductor coil mounted on one magnet detects the second magnet by measuring the change in inductance due to eddy current induced on the nickel-plated surface of the second magnet. The change in the inductance is proportional to the change in distance between the magnets. The sensor was first calibrated by using polycarbonate sheets to simulate the intestine tissue. We are able to detect up to 6 mm of spacing between the magnets. Pig intestine from Yorkshire pigs was used to characterize the sensor. We are able to distinguish up to five distinct layers of the intestine from the large intestine. This sensing mechanism can indicate the operating surgeon the exact thickness of the tissue compressed between the two magnets. The surgeon can thus be sure of formation of a clean anastomosis and avoid the likelihood of the magnets sliding away or uncoupling.