Basu Anisha S, Majerus Steve, Ferry Elizabeth, Makovey Iryna, Zhu Hui, Damaser Margot S
1 Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
2 Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
Proc Inst Mech Eng H. 2019 Jan;233(1):100-113. doi: 10.1177/0954411918754925. Epub 2018 Jan 29.
There has been recent interest in placing pressure-sensing elements beneath the bladder mucosa to facilitate chronic bladder pressure monitoring. Wired submucosal sensors with the wires passed through detrusor have been demonstrated in vivo, with limited chronic retention, potentially due to the cable tethering the detrusor. Published studies of submucosal implants have shown that high correlation coefficients between submucosal and lumen pressures can be obtained in caprine, feline, and canine models. We have developed a wireless pressure monitor and surgical technique for wireless submucosal implantation and present our initial chronic implantation study here. Pressure monitors were implanted (n = 6) in female calf models (n = 5). Five devices were implanted cystoscopically with a 25-French rigid cystoscope. One device was implanted suprapubically to test device retention with an intact mucosa. Wireless recordings during anesthetized cystometry simultaneous with catheter-based reference vesical pressure measurements during filling and manual bladder compressions were recorded. Individual analysis of normalised data during bladder compressions (n = 12) indicated high correlation (r = 0.85-0.94) between submucosal and reference vesical pressure. The healing response was robust over 4 weeks; however, mucosal erosion occurred 2-4 weeks after implantation, leading to device migration into the bladder lumen and expulsion during urination. Wireless pressure monitors may be successfully placed in a suburothelial position. Submucosal pressures are correlated with vesical pressure, but may differ due to biomechanical forces pressing on an implanted sensor. Fully wireless devices implanted beneath the mucosa have risk of erosion through the mucosa, potentially caused by disruption of blood flow to the urothelium, or an as-yet unstudied mechanism of submucosal regrowth. Further investigation into device miniaturisation, anchoring methods, and understanding of submucosal pressure biomechanics may enable chronic submucosal pressure monitoring. However, the risk of erosion with submucosal implantation highlights the need for investigation of devices designed for chronic intravesical pressure monitoring.
最近，人们对在膀胱黏膜下方放置压力传感元件以促进慢性膀胱压力监测产生了兴趣。已在体内证明了带有穿过逼尿肌的导线的有线黏膜下传感器，但慢性留置有限，这可能是由于电缆束缚了逼尿肌。已发表的关于黏膜下植入物的研究表明，在山羊、猫和犬模型中，黏膜下压力与管腔内压力之间可获得高相关系数。我们开发了一种无线压力监测器和用于无线黏膜下植入的手术技术，并在此展示我们的初步慢性植入研究。在雌性小牛模型（n = 5）中植入了压力监测器（n = 6）。使用25法式硬膀胱镜经膀胱镜植入了5个装置。经耻骨上植入了1个装置，以测试在黏膜完整的情况下装置的留置情况。记录了麻醉下膀胱测压期间的无线记录，同时记录了充盈期和手动膀胱按压期间基于导管的参考膀胱压力测量值。对膀胱按压期间的标准化数据（n = 12）进行的个体分析表明，黏膜下压力与参考膀胱压力之间具有高度相关性（r = 0.85 - 0.94）。在4周内愈合反应良好；然而，植入后2 - 4周发生了黏膜糜烂，导致装置迁移到膀胱腔内并在排尿时排出。无线压力监测器可能成功放置在尿路上皮下方位置。黏膜下压力与膀胱压力相关，但由于作用于植入传感器的生物力学力，可能会有所不同。植入黏膜下方的完全无线装置有通过黏膜侵蚀的风险，这可能是由于尿路上皮血流中断或尚未研究的黏膜下再生机制所致。对装置小型化、固定方法以及对黏膜下压力生物力学的理解进行进一步研究，可能实现慢性黏膜下压力监测。然而，黏膜下植入的侵蚀风险凸显了对设计用于慢性膀胱内压力监测的装置进行研究的必要性。
