Valve Regulated Implantable Intrathecal Drug Deliver for Chronic Pain Management.

MEMS;Drug Delivery;Valve;Chronic Pain;Piezoelectric;Volume Efficiency;Electrical Engineering;Engineering;Electrical Engineering

Evans, Allan T.Yoon, Euisik ;

University of Michigan

关键词: MEMS;    Drug Delivery;    Valve;    Chronic Pain;    Piezoelectric;    Volume Efficiency;    Electrical Engineering;    Engineering;    Electrical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/75815/evansall_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Chronic pain afflicts an estimated 100 million people in the United States with annual costs exceeding $100 billion.Treatment modalities for severe chronic pain include implantation of an intrathecal drug delivery device (IDDD).Conventionally, these devices are of two types: passive, permitting the delivery of a single analgesic mixture at a fixed rate; or active, permitting variable delivery by virtue of a peristaltic pump.This thesis presents an implantable system for medication delivery from multiple reservoirs with micromachined components.These components permit the use of an architecture that can provide superior volume efficiency and permit complex multi-drug delivery protocols.The system comprises three main components: regulatory valves, pressurized reservoirs, and control electronics.Important design considerations for each of these components are emphasized.Piezoelectric microvalves were designed and tested for use with aqueous flows.Two types of spring pressurized reservoirs were also designed and tested for feasibility in an IDDD.Reservoirs were pressurized using springs fabricated from silicon and generated up to 80kPa of pressure.Alternative reservoirs were pressurized using compressive metal springs and generated up to 18kPa of pressure.A first-generation system was developed that demonstrated controlled diffusion into agar gel.Water flow was regulated from 0.2-5mL/day, and bolus delivery was demonstrated.A second-generation system utilizing a two-valve manifold with embedded sensors was used to independently regulate isopropyl alcohol flow at set rates between 0.05-1mL/hr.Both systems demonstrated liquid delivery at intrathecal flow rates using continuous and duty-cycle flow regulation.Outlet pressure sensors were used to detect acute catheter occlusions and disconnects.A smart refill port was developed to allow for power transfer rates necessary to recharge batteries during a reservoir refill session.Recharging at current rates up to 500mA was demonstrated.The proposed valve-regulated architecture and two preliminary prototypes allowed evaluation of potential solutions to challenges for application of the architecture in an IDDD.Recommendations for future systems and plans for bench-top and in vitro testing are detailed.The proposed work may lead to a system that provides the functionality of commercially available implantable drug delivery devices with high volume efficiency, and the ability to independently regulate multiple medications.