Surgery – Controlled release therapeutic device or system – Implanted dynamic device or system
Reexamination Certificate
1999-09-13
2001-11-13
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Controlled release therapeutic device or system
Implanted dynamic device or system
C604S502000, C604S132000
Reexamination Certificate
active
06315769
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to implantable medical devices and associated pumps for infusing a fluid into a body, and the methods and construction of such devices. Additionally, the present invention concerns the means by which an implantable medical device and the pump or drug reservoir contained within it measures the amount of fluid contained therein.
BACKGROUND OF THE INVENTION
The use of implantable fluid medication dispensers is presently well known in the art. Examples of implantable fluid medication dispensers are contained within U.S. Pat. Nos. 5,328,460, 5,443,450 and 5,643,207. Such dispensers are used to dispense a specified amount of medication into a patient's body, and may, for example, deliver low doses of morphine into a patient's body to treat cancer pain.
Implantable fluid medication dispensers typically include an internal fluid medication reservoir for receiving, storing and dispensing a supply of a fluid medication. Such a reservoir is generally included within a housing of some shape or form that may be implanted in the body. Other components of such a device include a power source (such as a battery), a mechanism for pumping the fluid medication into the patient's body, and a programmable mechanism to assist in dispensing the fluid medication according to a predetermined schedule.
Because those fluid medication dispensers are implanted within a patient's body, they must in general be periodically replenished with medication. As a result, implantable fluid medication dispensers may include some means to replenish the fluid medication within the reservoir. U.S. Pat. No. 5,443,450 to Kratoska et al. discloses a typical reservoir refill assembly. Unfortunately, determining the level of medication contained within a fluid medication dispenser has proved to be problematic. At present, the absence of a fluid medication being dispensed to a patient is generally detected by physiological measures. Such measures may include symptoms associated with the malady to which the fluid medication is directed to prevent or abate.
There exists, therefore, a significant need for improvement in the measuring abilities of such implantable medication dispensers. Instead of relying upon symptomatic factors to determine when an implantable fluid medication device is in need of a replenishment of fluid which may cause unwarranted pain to the patient, it would be desirable to provide a means to determine the amount of fluid remaining in another more efficacious manner. The present invention fulfills at least some of these needs and provides further advantages.
Disclosures relating to implantable medication dispensers include the U.S. Patents listed below in Table 1.
TABLE 1
Prior Art, U.S. patents.
5,328,460
July, 1994
Lord, et al.
5,443,450
August, 1995
Kratoska, et al.
5,643,207
July, 1997
Rise
As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, at least some of the devices and methods disclosed in the patents contained within Table 1 may be modified advantageously by using the teachings of the present invention.
SUMMARY OF THE INVENTION
The present invention overcomes at least some of the disadvantages of the prior art by providing a method of and apparatus for measuring the level of a fluid medication within an implantable pump apparatus and fluid medication dispenser, and by providing a structure that improves same.
The present invention has certain objects. That is, various embodiments of the present invention provide solutions to at least some of the problems existing in the prior art respecting the measurement of the amount of fluid remaining in an implantable medication dispenser, such as one or more of:
(a) difficulty in providing an accurate measurement of the amount of fluid medication remaining within the implantable pump apparatus;
(b) the inability to provide an accurate diagnosis concerning the amount of fluid medication remaining within an implantable pump apparatus without relying on physiological factors or symptoms of a patient; and
(c) the inability to provide a safe and nonintrusive means to measure the amount of fluid medication remaining within an implantable pump apparatus without causing harm to a patient;
(d) basing the requirement of additional fluid medication on the detection of physiological factors;
(e) basing the requirement of additional fluid medication on a patient's symptoms; and
(f) basing the requirement of additional fluid medication on other inaccurate and potentially unsafe methods.
The present invention provides solutions to at least some of the foregoing problems.
Various embodiments of the present invention provide one or more of the following advantages:
(a) providing an accurate indication of the amount of fluid remaining within an implantable fluid medication dispenser;
(b) providing a safe manner in which the amount of fluid remaining within an implantable fluid medication dispenser is measured;
(c) providing a manner in which the amount of fluid remaining within an implantable fluid medication dispenser is measured without relying on physiological factors of the patient;
(d) providing a manner in which the amount of fluid remaining within an implantable fluid medication dispenser is measured without relying on symptoms of the patient; and
(e) providing a manner in which the amount of fluid remaining within an implantable fluid medication dispenser is measured without relying on other inaccurate and potentially unsafe methods.
Some embodiments of the present invention have certain features relating to the measurement of a fluid medication contained within an implantable fluid medication dispenser, including one or more of:
(a) an expandable reservoir for receiving a specified amount of a fluid medication that is situated within an enclosure;
(b) a pressure sensitive resistor attached to the bottom of the enclosure; and
(c) a spring situated between the reservoir and the resistor for translating the displacement of the reservoir to a force applied to the spring.
REFERENCES:
patent: 4482346 (1984-11-01), Reinicke
patent: 5328460 (1994-07-01), Lord et al.
patent: 5443450 (1995-08-01), Kratoska et al.
patent: 5643207 (1997-07-01), Rise
patent: 6152898 (2000-11-01), Olsen
patent: 6228050 (2001-05-01), Olsen et al.
Bakels Arnoldus
Peer Twan
Berry Thomas G.
Medtronic Inc.
Nguyen Anhtuan T.
Woods Thomas F.
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