Batteryless implantable dual-sensor capsule for esophageal reflux monitoring.

BACKGROUND: Chronic GERD affects approximately 15% of adults in the United States and is one of the most prevalent clinical conditions involving the GI tract. The commercial tools for monitoring GERD include multichannel intraluminal impedance (MII) probes and pH-sensing capsules. However, MII probes cause discomfort, which alters patients' regular activities, whereas the pH-sensing capsule lacks the ability to detect weak or nonacid episodes, misses reflux episodes with similar pH values, and has a limited sampling rate and battery life. OBJECTIVE: To develop and test an implantable batteryless dual-sensor capsule that can be used to diagnose and monitor GERD. DESIGN: The implanted capsule is wirelessly powered by an external device. Simulated reflux episodes were created in 3 live porcine models. Impedance and pH data were continuously measured and recorded. INTERVENTION: The implant capsule was placed in the esophagus along with a commercial pH-sensing capsule for comparison. MAIN OUTCOME MEASUREMENTS: Precise impedance and pH readouts were obtained and compared with those from a commercial pH-sensing capsule. RESULTS: The wireless energy supplied by the external unit was strong enough to power the implant. The pH sensor accurately measured pH levels and the impedance sensor precisely located the reflux episodes. LIMITATION: Simulated reflux events in a pig model. CONCLUSION: Our wireless sensors are reliable in operation and provide accurate assessment of simulated reflux episodes. The entire device can potentially be used to diagnose and monitor GERD.

Biomechanical properties of the vaginal wall: effect of pregnancy, elastic fiber deficiency, and pelvic organ prolapse.

OBJECTIVE: The purpose of this study was to identify pregnancy-induced changes in biomechanical properties of the vaginal wall and to compare these with fibulin-5 knockout mice (Fbln5(-/-)) with and without prolapse. STUDY DESIGN: Mid-vaginal segments of nonpregnant and late-pregnant wild-type mice, Fbln5(-/-) with prolapse mice and Fbln5(-/-) mice without prolapse were studied. Tissue length at failure, maximal strain, maximal stress, and tissue stiffness were determined. RESULTS: Compared with nonpregnant mice, vaginas of pregnant and Fbln5(-/-) (with prolapse) mice exhibited decreased maximal stress, increased distensibility and strain, and decreased stiffness. Tissues from Fbln5(-/-) mice without prolapse were similar to nonpregnant wild-type animals. CONCLUSION: Pregnancy confers remarkable changes in the vaginal wall that include increased distensibility and decreased stiffness and maximal stress. Elastinopathy alone is insufficient to cause significant changes in these properties, but prolapse confers additional alterations in distensibility and stiffness that are similar to those changes that have been observed in pregnancy. These changes may contribute to the poor durability of many restorative surgical procedures for prolapse.