Implantable wireless sensor

Abstract

The progress of a endovascular aneurysm repair can be monitored by inserting a pressure transducer sensor using a catheter into the sac during endovascular aneurysm repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of loading the sensor into a catheter, and deploying into the aneurysm sac. This invention also has other applications for measuring physical properties in patients or in other sites.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is based upon co-pending, commonly assigned U.S. provisional patent application Ser. No. 60 / 503,745, filed Sep. 16, 2003, incorporated herein by reference in its entirety.FIELD OF THE INVENTION [0002] The application is directed to an implantable wireless sensor. More particularly, this invention is directed to a wireless, unpowered, micromechanical sensor that can be delivered using endovascular techniques, to measure a corporeal parameter such as pressure or temperature. BACKGROUND OF THE INVENTION [0003] Abdominal aortic aneurysms represent a dilatation and weakening of the abdominal aorta which can lead to aortic rupture and sudden death. Previously, the medical treatment of abdominal aortic aneurysms required complicated surgery with an associated high risk of injury to the patient. More recently, endografts (combining stents and grafts into a single device) have been developed that can be inserted through small inc...

AI Technical Summary

Benefits of technology

"The present invention is a device that can be implanted into the human body to measure corporeal parameters such as pressure or temperature. It is small, accurate, precise, durable, robust, biocompatible, and insensitive to changes in body chemistry. The device can be introduced into the sac of an abdominal aneurysm or a chamber of the heart using standard endovascular catheter techniques. It can be fabricated using MEMS technology and is sealed in a hermetically scaled chamber that is pressure sensitive. The device can be attached to a tethering system and detached from it after the delivery vehicle is removed from the patient. The technical effects of this invention include the ability to measure important parameters without the need for wires or an internal power supply, and the potential to improve the accuracy and precision of sensor placement."

Problems solved by technology

Abdominal aortic aneurysms represent a dilatation and weakening of the abdominal aorta which can lead to aortic rupture and sudden death.

Previously, the medical treatment of abdominal aortic aneurysms required complicated surgery with an associated high risk of injury to the patient.

A significant problem with endografts is that, due to inadequate sealing of the graft with the aorta, leaks can develop that allow blood to continue to fill the aneurysmal sac.

Left undiscovered, the sac will continue to expand and potentially rupture.

These procedures are expensive, not sensitive, and painful.

In addition, they subject the patient to additional risk of injury.

While some of the above objectives are accomplished, this device has multiple problems that would make its use impractical.

For example, the sensor system disclosed in the Van Bockel patent relies on a mechanical sensing element that cannot be practically manufactured in dimensions that would allow for endovascular introduction.

In addition, this type of pressure sensor would be subject to many problems in use that would limit its accuracy, stability and reliability.

This would impact the device's ability to maintain accurate pressure reading over long periods of time.

A fundamental problem with sensors is their tendency to drift over time.

A sensor described in the Van Bockel patent would be subject to drift as a result of its failure to seal the pressure sensing circuit from the external environment.

Also, by failing to take advantage of specific approaches to electronic component fabrication, allowing for extensive miniaturization, the Van Bockel device requires a complex system for acquiring data from the sensor necessary for the physician to make an accurate determination of intra-aneurysmal pressure.

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