Surgery – Instruments – Electrical application
Reexamination Certificate
2000-04-12
2003-09-30
Gibson, Roy D. (Department: 3739)
Surgery
Instruments
Electrical application
C606S034000
Reexamination Certificate
active
06626902
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus and method for catheterization of the tissues and fluid spaces, including blood vessels, of the human body. The invention also relates to the method by which diagnostic and therapeutic agents and/or procedures may be delivered to any of those body parts or regions. In particular, the present invention relates to the design and use of a multi-lumen catheter for providing multiple, and not necessarily complimentery functions, such as sampling of the fluids within the extracellular and interstitial spaces of the brain, spinal cord, or other body tissues, concurrently with drug delivery, electrical recording/stimulating, or the delivery of any other type of therapy into the same tissues in accordance with the need for such therapies.
2. Background of the Art
Surgical procedures, especially neurosurgical procedures that involve open craniotomy, carry an intrinsically high level of risk of infection and hemorrhage. A variety of new techniques aimed at minimizing the invasiveness of interventional procedures have been introduced in the hope of reducing the surgical risk and shorten a patient's hospital stay and overall rehabilitation. Placement of probes and catheters into the brain using stereotactic and image-guided procedures provides one means of minimizing these risks. However, many types of interventional procedures, including those that require drug delivery into the brain, sometimes require either catheterization at multiple target points, or subsequent re-implantation of the catheter to optimize the therapy being delivered to the brain.
Current methods of catheterization of the parenchymal tissues of the brain make it possible to measure intracranial pressure (U.S. Pat. No. 5,107,847), deliver drugs in a rate-controlled manner (U.S. Pat. No. 5,836,935), infuse various substances into the brain (U.S. Pat. No. 5,720,720), and convey fluids out of the brain (U.S. Pat. No. 5,772,625). Very recent technological developments are now leading to intraparenchymal catheterization systems that can be positioned within the brain by magnetic stereotaxis (U.S. Pat. Nos. 5,125,888; 5,707,335; 5,779,694), that are visible under magnetic resonance (MR) imaging (U.S. patent application Ser. No. 09/131,031 and U.S. Pat. No. 6,026,316), and that contain multi-purpose electrodes (U.S. Pat. No. 5,843,093). In addition, there are several types of implantable neurostimultor devices that have been disclosed. These include those described by Otten (U.S. Pat. No. 5,344,439), Hess et al. (U.S. Pat. No., 4,800,898), and Tarjan et al. (U.S. Pat. No. 4,549,556) as three examples thereof. However, none of the available methods of intraparenchymal catheterization can carry out multiple input-output functions at the same time with the same implanted device. With the exception of the method taught by Otten (U.S. Pat. No. 5,344,439), an already implanted device or part of an implanted device must be withdrawn before another probe is subsequently inserted into the tissue to perform additional functions. U.S. Pat. No. 5,788,713 describes the availability of both a delivery lumen and sampling lumen on a single catheter system.
One of the significant problems with delivering drugs directly into living tissue is assuring that the drug is accurately distributed to target receptor locations. The efficacious delivery of therapeutic agents for the treatment of brain tumors or neurodegenerative diseases, as two examples, requires that the agents be delivered as close to their receptors in the brain as possible, while minimizing increases in intracranial pressure during and after drug delivery. Liquid drug agents delivered into the brain through implanted catheters will disperse from the site of injection at variable rates depending on a number of factors, including the physicochemical characteristics of the drug, capillary uptake, metabolic degradation and excretion of the drug, size of the extracellular space, geometry of the brain cell microenvironment and input flow-rate and line pressure of the infusion system or other device that is pumping the drug into the brain. The degree to which each of these factors influences the distribution of a particular drug agent may be an important determinant of the effectiveness of drug treatment of diseases of the central nervous system. Additionally, the inventors have determined that it is increasingly important to determine other local characteristics of the region where active materials are delivered that can effect the efficacy or optimization of the treatment, such as pH, osmololity, viscosity, electrolyte content, temperature, fluid flow rates, and concentrations of specific ingredients. No present systems enable both the delivery of therapeutic materials and the measurement of significant local properties (except for the single noted instance of delivery and physical sampling).
Ideally, the injected, infused, or retroprofused material (e.g., a material that is “biologically active,” that is a material which influences, increases, decreases or supplements biological activities on the cellular or macro-organ level, such activities, for example, including any chemical production, cell reproduction, hormone production, enzyme production, responsive activity, and the like) infiltrates the extracellular space, and the subsequent distribution of the drug within the tissues is governed mainly by its molecular weight, molecular radius, the structure and hydraulic conductivity of the tissue matrix into which the material has been injected, and the hydrodynamics of the infusion process. However, various flow scenarios may lead to tissue swelling, an increase in ICP (intracranial pressure) and, secondarily, altered interstitial transport of the drug solute.
Invasive ICP devices have generally evolved in two basic directions. The first is based on implanting a sensor within the cranium. The second is based on mounting the sensor externally and connecting the measurement site through a fluid-filled transmission line. The three main sites for ICP monitoring are the lateral ventricle, the extradural space, and the subdural or subarachmoid spaces.
U.S. Pat. No. 4,014,319 to Favre discloses an intracranial pressure transducer comprising a small sealed capsule positioned in a trephined hole in the patient's skull, wherein a sensor diaphragm in contact with the dura mater is displaced by changes in intracranial pressure and produces an output signal proportional to the change in intracranial pressure. U.S. Pat. No. 4,026,276 to Chubbuck discloses a pressure monitoring apparatus implantable in the cranium, wherein the apparatus comprises a passive resonant circuit with inductance and capacitance capability for measuring intracranial pressure by comparison to a reference ambient pressure. U.S. Pat. No. 4,062,354 to Taylor, et al. discloses an intracranial pressure transducer system comprising a holding bracket containing sensor elements which is positioned against the dura of the brain, wherein the elements within the holding bracket transmit electromagnetic signals related to the intracranial pressure to a receiver outside the patient's body. U.S. Pat. No. 4,080,653 to Barnes, et al. discloses a method and apparatus for recording intracranial pressure utilizing a transducer amplifier. U.S. Pat. No. 4,114,603 discloses an intracranial pressure monitoring device comprising a pressure-sensitive catheter insertable between the dura mater and arachnoid membrane.
U.S. Pat. No. 4,114,606 discloses a monitoring apparatus for intracranial pressure measurement, wherein electromagnetic radiation is imposed on a passive circuit implanted in the cranium, the frequency at which the radiation is absorbed reflecting intracranial pressure. U.S. Pat. No. 4,147,161 to Ikebe, et al. discloses a system for measuring or monitoring intracranial pressure which comprises a non-elastic detecting pouch inserted between the skull and the brain, wherein a pressure measuring device in the liquid in the pouch indirec
Gillies George T.
Kucharczyk John
Gibson Roy D.
Mark A. Litman & Assoc. P.A.
University of Virginia Patent Foundation
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