INTRATHECAL CATHETER

Abstract

An intrathecal catheter for delivering fluid to, or withdrawing fluid from, the cerebrospinal fluid compartment of a patient, includes a proximal end and a distal portion. The distal portion has an outer diameter of about 1 mm or less, a bending stiffness of about 0.002 pounds per square inch or less, and a distal end. A delivery region is located between the proximal end and the distal end, and a lumen extends from the proximal end to the delivery region. The catheter may further include a coiled structure region to prevent dislodgement of the catheter from a tissue in which the coiled structure is implanted, for example the cisterna magna. The catheter may also include tines to anchor portions of the catheter, for example to a portion of the spinal canal.

Description

RELATED APPLICATIONS

This Application claims the benefit of Provisional Application Ser. No. 60/868,901, filed Dec. 6, 2006, and of Provisional Application Ser. No. 60/868,904, filed Dec. 6, 2006, which applications are hereby incorporated herein by reference in their respective entireties to the extent that they do not conflict with the present disclosure.

FIELD

The present disclosure relates, inter alia, to implantable medical catheters, and particularly to intrathecal catheters.

BACKGROUND

A variety of catheters are available for delivering therapeutic agents to patients. Configurations of the catheters vary according to the use for which they are intended. For example, intravascular catheters may include a coiled region that presses against the vasculature to hold the catheter in place during use. The use of tines has also been employed for purposes of anchoring a catheter relative to a tissue location. The materials and properties of the catheters may be selected to be compatible with the therapeutic agent being delivered and the tissue into which the catheter is to be implanted.

Recently, therapies have been proposed for delivering therapeutic agents to the cisterna magna. However, to date, no catheters have been described that would be suitable for such delivery, particular for long term delivery; e.g., as typically associated with implantable infusion devices.

SUMMARY

The present disclosure describes catheters and kits and systems suitable for delivering therapeutic agents to the cisterna magna, particularly when the catheters are advanced rostrally through the spinal canal to the cisterna magna.

In an embodiment, a catheter includes a proximal end and a distal portion. The distal portion has an outer diameter of about 1 mm or less, a bending stiffness of between about 0.00005 pound inch squared (1.4×10⁻⁸ kg-meter squared) to about 0.002 pound inch squared (5.8×10⁻⁷ kg-meter squared), and a distal end. A delivery region is located between the proximal end and the distal end, and a lumen extends from the proximal end to the delivery region. The material forming the distal portion of the catheter imparts a sufficient hoop strength such that the lumen resists collapsing when implanted in the cerebrospinal fluid compartment of a subject. The catheter may further include a coiled structure region to prevent dislodgement of the catheter from a tissue in which the coiled structure is implanted, for example the cisterna magna, or to allow for growth of the patient in height when implanted in a young patient. The catheter may also include tines to anchor portions of the catheter, for example to a portion of the spinal canal.

In an embodiment, a catheter includes a proximal end and a distal portion. The distal portion includes a delivery region and a coiled structure region. A lumen extends from the proximal end to the delivery region. One or more tines are located on the catheter proximal to the delivery region and the coiled structure region.

The catheters described herein provide one or more advantages over existing catheters. For example, in various embodiments, the catheters include a flexible distal end portion that can reduce or prevent tissue damage when being advanced through delicate tissue such as the cisterna magna. In various embodiments, the catheters are configured to provide anchoring within the cisterna magna or spinal canal to prevent dislodgement of a delivery region of the catheter from the cisterna magna. These and other advantages will become evident upon reading the disclosure that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic longitudinal cross sectional view of a representative catheter.

FIG. 2A is schematic side view of a representative catheter.

FIG. 2B is a schematic exploded side view of a representative catheter, adaptor, and second catheter.

FIG. 3 is a schematic longitudinal cross section of a distal portion of a representative catheter.

FIG. 4 is a schematic longitudinal cross section of a representative distal portion of a catheter with a stylet inserted into a lumen of the catheter.

FIG. 5 is a schematic longitudinal cross section of a stylet inserted into a lumen of a catheter.

FIG. 6 is a schematic longitudinal cross section of a portion of a catheter including a visualization marker.

FIG. 7 is a schematic longitudinal cross section of a representative distal portion of a catheter with a stylet inserted into a lumen of the catheter.

FIG. 8 is a schematic perspective view of a coiled structure region of a representative catheter.

FIG. 9 is a schematic longitudinal section of a portion of a representative catheter having a coiled structure region and tines.

FIG. 10 is a schematic side view of an implantable infusion device with an attached catheter.

FIG. 11 is a schematic view of an infusion device and associated catheter implanted in a patient.

The drawings are not necessarily to scale. Like numbers used in the figures refer to like components, steps and the like. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration several specific embodiments of devices, kits, systems and methods. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense.

Devices and methods for delivering large molecules to the central nervous system (CNS) are discussed. The devices and methods described allow for less invasive and more effective procedures to be employed for delivering medications comprised of drugs, small molecules, or large molecules to the brain.

Definitions

All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

As used herein, “the cerebrospinal fluid compartment” of a subject means the space within the central nervous system within the anatomy of the subject that is filled with cerebrospinal fluid. The cerebrospinal fluid compartment comprises the cisterna magna, the lateral ventricles, the third ventricle, the fourth ventricle, the foramen of Magendie, the foramen of Monro, the formina of Luschka, the cerebral aquaduct, the subarachnoid space surrounding the brain and the spinal cord, the dural venous sinuses, spaces surrounding the cranial nerves, and other spaces of the central nervous system containing cerebrospinal fluid.

As used herein, “visualization marker” means material that is visible by surgical navigation instrumentation. A marker may be a discrete band or may be in any other suitable form for visualization purposes. Markers may comprise radiopaque material, such as platinum, tungsten, gold or iridium. Markers may be incorporated into catheter material or may be affixed to a portion of a catheter.

As used herein, “subject” means an animal into which a catheter or a portion thereof may be implanted and includes mammals, such as humans.

As used herein, “comprising”, “including”, and the like are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”

As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

Abbreviations of units of measurements as used herein are abbreviations commonly used in the art unless otherwise specified. For example, “mm” means millimeter, “cm” means centimeter, and “kg” means kilogram.

Described herein are catheters having properties that are useful for delivering fluid to or withdrawing fluid from the cisterna magna of a subject. However, it will be understood that the properties of the catheters may be useful for delivering or withdrawing fluid to other areas of a subject.

Referring to FIG. 1, catheter 100 has a proximal end 10 and a distal portion 20. As used herein, “proximal” refers to the portion of the catheter closer to a fluid delivery or withdrawal device and “distal” refers to the portion of the catheter further from the fluid delivery or withdrawal device when in use. Distal portion 20 comprises a distal end 30 and a delivery region 40. Catheter 100 comprises a lumen 50 extending from proximal end 10 to delivery region 40. Delivery region 40 in FIG. 1 is depicted as a side hole. However, it will be understood that delivery region 40 may be one or more side holes, one or more porous regions (not shown) that extend around or substantially around a portion of distal portion 20 of catheter 100, an opening (not shown) at distal end 30, or the like. It may be desirable in many circumstances to have more than one opening for fluid to be delivered or withdrawn in case one or more openings becomes clogged during or following implantation of catheter 100.

As shown in FIG. 1, distal portion 20 of catheter 100 has an outer diameter (o.d.). In various embodiments o.d. of distal portion 20 is less than about 1 mm. For example, o.d. may be less than 0.75 mm or less than 0.62 mm. Catheter 100 having a distal portion 20 with an o.d. of less than about 1 mm may tend to be too limp to be pushed large distances within a subject's body, such as from the intrathecal lumbar region to the cisterna magna, particularly if made from certain polymeric materials. However, such a limp catheter 100 tends to reduce the chance of damaging tissue into which catheter 100 is inserted, such as the intrathecal space. Accordingly, it may be desirable to employ a stylet 200 (see, e.g., FIG. 3) to direct catheter 100 to the appropriate location within the subject. Of course, a long introducer (not shown) or guiding catheter (not shown) may be used to provide a guide through which the thinner catheter 100 could be pushed without bending or going off course.

In various embodiments, distal portion 20 of catheter 100 has a bending stiffness low enough to avoid significant damage to tissue, such as the arachnoid membrane, as distal portion 20 of catheter 100 is advanced through the tissue. Bending stiffness can be measured using the following formula:

Mρ=E I,

• • where M=bending moment;
  • ρ=radius of curvature;
  • E=Young's Modulus for the material selected; and
  • I=moment of inertia for the beam.

The moment of inertia for simple cross sections are readily available to those skilled in the art, e.g., through textbooks or handbooks. Otherwise, the moment of interia can be calculated as follows:

$I_{\mathrm{solidcylinder}}=\frac{\pi }{64}{\left(\mathrm{OD}\right)}^4$

where OD is the outside diameter of the stylet, or

$I_{\mathrm{hollowtube}}=\frac{\pi }{64}\left({\left(\mathrm{OD}\right)}^4-{\left(\mathrm{ID}\right)}^4\right)$

where OD is the outside diameter of the cannula and ID is the inside diameter.

In various embodiments, the bending stiffness of distal portion 20 of catheter 100 may be about 0.002 pound-inch squared (5.8×10⁻⁷ kg-meter squared) or less, such as about 0.001 pound-inch squared (2.9×10⁻⁷ kg-meter squared) or less, to prevent significant damage to delicate tissue, such as the tissue surrounding the spinal canal or the cisterna magna, as distal portion 20 is being advanced through the tissue. In numerous embodiments, the bending stiffness of distal portion 20 of catheter 100 is between about 0.002 pound-inch squared (5.8×10⁻⁷ kg-meter squared) and 0.00005 pound-inch squared (1.4×10⁻⁸ kg-meter squared). Of course a catheter having such a low bending stiffness may be difficult to advance through the spinal canal. Accordingly, it may be desirable to use a stylet 200 (see, e.g., FIG. 3) to assist in directing catheter 100 to the appropriate location within the subject. Distal portion 20 of catheter 100 and stylet 200 disposed within lumen 50 of distal portion 20 of catheter 100, in combination, should be sufficiently stiff to advance distal portion 20 of catheter 100 through tissue. If distal portion 20 of catheter 100 is to be advanced through the spinal canal, distal portion 20 of catheter 100 and stylet 200 disposed within lumen 50 of distal portion 20 of catheter 100, in combination, should have a bending stiffness of about 0.01 pounds inch squared (2.9×10⁻⁶ kg meter squared) or greater.

It will be desirable for distal portion 20 of catheter 100 to have sufficient hoop strength to resist collapse of the lumen 50 when the catheter 100 is implanted in the cerebrospinal fluid compartment of the subject. Examples of material that can impart sufficient hoop strength at the diameters discussed above include polypropylene and polyethylene.

Distal portion 20 of catheter 100 may vary in length to achieve a desired effect; e.g., advancement into the cisterna magna from a lumbar insertion. For example, the distal portion 20 may be about 40 cm or longer, about 50 cm or longer, about 60 cm or longer, about 70 cm or longer, about 80 cm or longer, about 90 cm or longer, or about 100 cm or longer. The longer the distal portion 20 of catheter 100, which may have a small outer diameter, the less likely that catheter 100 will damage tissue as catheter 100 is advanced within a subject, and thus the more likely that it may be advanced extended distances in delicate tissue. In addition, due to a small outer diameter, distal portion 20 of catheter 100 may have a small inner diameter, which will permit fine control of fluid to be delivered. However, it should be noted that due to resistance to fluid flow associated with smaller inner diameter, catheter 100 preferably has a sufficiently large inner diameter to permit bolus delivery of fluid through the catheter 100. While it will be understood that resistance may vary from solution to solution or catheter to catheter, it may be difficult to deliver substantial bolus amounts if the inner diameter of the catheter (i.e., the lumen diameter) is less than about 0.127 mm.

In various embodiments, proximal end 10 of catheter 100 is configured to be coupled to an infusion device 300 (see, e.g., FIG. 10). Proximal end 10 of catheter 100 may be coupled to infusion device 300 using any known or future developed mechanism. In embodiments wherein the outer diameter of distal portion 20 of catheter 100 is small, catheter 100 may include a tapered portion 500 between proximal end 10 and distal end 30 to provide a proximal end 10 with a larger outer diameter (see, e.g., FIG. 2A) to facilitate coupling of the catheter 100 to the infusion device 300. As shown in FIG. 2B, an adaptor 600 may be used to fluidly couple the lumen of the catheter 100 to a second catheter 700, which may then be coupled to the infusion device. Of course, the adaptor 600 may be configured to couple catheter 100 directly to the infusion device.

Referring to FIG. 3 and in accordance with various embodiments, the lumen 50 of the catheter is configured to slidably receive a stylet 200. In the depicted embodiment, distal portion 20 of catheter 100 has a side hole delivery region 40. Disposed within lumen 50 is a stylet 200 including a distal end 210. As used herein, “stylet” means an elongated device capable of being inserted into lumen 50 of catheter 100 and assisting the movement of distal portion 20 of catheter 100 to a desired location in a subject, and includes a guidewire and the like. Stylet 200 may be used to push distal portion 20 of catheter 100 or may be used to impart stiffness to distal portion 20 of catheter 100 to allow catheter 100 to be positioned within a subject, e.g., where the stylet 200 and the catheter 100 are advanced together. It will generally be desirable for excess catheter material to extend beyond distal end 210 of stylet 200 to allow material softer than stylet 200 to be exposed to tissue as distal portion 20 of catheter 100 and stylet 200 are advanced. Any way to ensure that distal end 210 of stylet 200 does not extend beyond distal end 30 of catheter 100 may be used. As shown in FIG. 3, a catheter 100 having a closed distal end 30 may be one way of preventing stylet 200 from extending beyond distal end 30 of catheter 100. Alternatively, catheter may be squeezed, e.g. by a user's fingers, to apply sufficient pressure to prevent relative longitudinal movement of stylet 200 to distal portion 20 of catheter 100 as distal portion 20 of catheter 100 and stylet 200 are advanced together.

FIG. 4 depicts an embodiment of a catheter 100 having a feature 70 to prevent accidental extension of stylet 200 beyond distal end 30 of catheter 100 or accidental protrusion of stylet 200 through side hole delivery region 40. As shown in FIG. 4, excess catheter material 80 may be present between the feature 70 and distal end 30 of catheter 100 to allow a material softer than stylet 200 to be exposed to tissue as catheter 100 and stylet 200 are being advanced. In the depicted embodiment, feature 70 is configured to receive distal end 210 of stylet 200, which may be useful in circumstances where it is desirable to use stylet 200 to push distal portion 20 of catheter 100.

Referring to FIG. 5, an alternative embodiment for preventing accidental extension of stylet 200 beyond distal end 30 of catheter 100 is shown. As shown in FIG. 5, stylet 200 may include a stop 230 or handle at the proximal region of stylet 200 that prevents distal end 210 of stylet 200 from extending beyond distal end 30 of catheter 100 during use. In various embodiments, the length of stylet 200 from stop 230 to distal end 210 of stylet 200 is less that the length of catheter 100 (if straightened) from proximal end 10 to distal end 30. In various embodiments, the length of stylet 200 from stop 230 to distal end 210 of stylet 200 is less than the length of catheter 100 (if straightened) from proximal end 10 to an opening of delivery region 40. It may be desirable for the length of stylet 200 to be shorter than the length of catheter 100 by an amount to allow sufficient excess catheter material to extend beyond distal end 210 of stylet 200 while catheter 200 is being advanced within a subject. The position of stop 230 on stylet 20 may be fixed or adjustable to the desired length.

Generally, stop 230 is configured to grippingly engage an outer surface of stylet 20 and to engage the proximal end of the catheter. If stop 230 is moveable along stylet 20, the stop 230 may exist in an open state and a closed or engaged state. In the open state the stop 230 is moveable. In the closed state the stop 230 is fixed relative to the stylet 20. In various embodiments, the stop 230 is actuatable between the open and closed states. Suitable actuatable mechanisms for stops 230 are well known and include set screws, squeezable handles or the like.

In various embodiments, kits including a catheter 100 as described herein and a stylet 200 are provided. Any suitable stylet 200, such as a stylet as described above, may be included in the kit. In numerous embodiments, the catheter 100 and the stylet 200 of the kit are provided in a single package.

Referring to FIG. 6, a cross-sectional representation of an embodiment of distal portion 20 of catheter 100 is shown. As shown in FIG. 6, a visualization marker 60 may be disposed in or about a portion of catheter 100 in proximity to delivery region 40 to serve as a proxy for identification of the location of the delivery region. Visualization marker 60 may be in the form of a band as shown in FIG. 6, or may take any other suitable form to serve as a means for localizing the placement of delivery region 40 by surgical navigation visualization techniques.

As shown in FIG. 7, stylet 200 may comprise visualization marker 220 at or near distal end 210 to further enhance visualization of navigation and placement of delivery region 40 of catheter 100. Visualization marker 220 may be in the form of a band as shown in FIG. 7, or may take any other suitable form to serve as a means for localizing distal end 210 of stylet 200, which may serve as a proxy for placement of delivery region 40 by surgical navigation visualization techniques. Visualization marker 220 may also be used to verify that distal end 210 of stylet 200 is not extended beyond distal end 30 of catheter 100 (as indicated by visualization marker 60 of catheter 100) during placement of catheter 100.

In various embodiments, at least a portion of distal portion 20 of catheter 100 comprises a coiled structure 90 when relaxed, as shown in FIG. 8. A “coiled structure”, as used herein, may have one or more loops or other nonlinear portions (e.g., a sigma structure) that may serve to anchor distal portion 20 of catheter 100 within a location of the body, such as the cisterna magna. Such a coiled structure 90 may be desirable in situations where catheter 100 is likely to undergo a strain due to body movements of the subject. For example, if catheter 100 is introduced into the intrathecal space of the spinal canal through a lumbar puncture and advanced rostrally so that distal portion 20 of catheter 100 is located in the cisterna magna, movement of the subject's head or neck may tend to dislodge distal portion 20 of catheter 100 from the cisterna magna. As such, a coiled structure portion 90 of distal portion 20 of catheter 100 may serve to provide strain relief to prevent pulling or dislodging of distal portion 20 of catheter 100. Such a coiled structure portion 90 may also be beneficial when catheter 100 is implanted in an infant or child, where growth of the spine may otherwise tend to dislodge distal portion 20 of catheter 100 from its desired location, e.g. the cisterna magna. The coiled structure portion 90 of distal portion 20 of catheter 100 is sufficiently pliable to be straightened when a stylet 200 is inserted into lumen 50 of catheter 100 and extended through coiled portion 90 of catheter 100. In addition to providing strain relief, coiled structure portion 90 may also serve to anchor distal portion 20 of catheter 100 in place.

It may be desirable to include one or more visualization markers 60 (not shown in FIG. 8) on coiled structure portion 90 to verify that the coiled structure portion 90 has been appropriately implanted or navigated. Alternatively, it may be desirable to incorporate radiopaque material into catheter material of coiled structure portion 90 to allow for visualization during or after implant.

Referring to FIG. 9, a representation of an embodiment of distal portion 20 of catheter 100 as it may appear implanted in a subject is shown. Distal portion 20, which may be implanted in the cisterna magna, comprises a coiled structure portion 90 comprising distal end 30 of catheter 100. Included in the depicted coiled structure portion 90 are delivery regions 40 and visualization marker 60. Placement of delivery region 40 within the coiled structure region 90 may serve to keep delivery region located away from a tissue of the subject, rather than allowing the delivery region to contact or be in close proximity to tissue of the subject when implanted. Such a configuration may be desirable to prevent granulomas that may occur with certain intrathecally delivered drugs.

While not shown, it will be understood that it may be desirable for coiled structure region 90 to comprise more than one visualization marker 60 or to have a visualization marker 60 extend over a substantial portion of coiled structure region 90, e.g., by incorporating a radiopaque material into the catheter at coiled structure region 90.

Distal portion 20 of catheter 100 may comprise one or more tines 110 to assist in anchoring distal portion 20, and more particularly delivery region 40. Tines 110 may be located at any location along catheter 100 that may result in anchoring the catheter 100 or reduce movement of delivery region 40. As shown in FIG. 9, tines 110 may be located further from distal end 30 of catheter 100 than coiled structure portion 90 (e.g., the tines are located proximal to the coiled structure region), e.g. at a location of catheter 100 to be implanted within a spinal canal. Also shown in FIG. 9, is that excess 120 catheter 100 may be placed in the spinal canal to provide slack to allow for growth of a subject, such as a child. Tines 110 may be made of any material that can provide sufficient anchoring to inhibit movement of the catheter relative to the tissue in which the tines 110 are anchoring the catheter. In the depicted embodiment, the tines 110 are oriented to allow rostral advancement of the catheter in the spinal canal but to inhibit caudal withdrawal or movement of the distal portion 20 of the catheter. However, the tines 110 may be retractable, as is known in the art, to prevent damage to the spinal canal upon withdrawal of the catheter. One example of retractable tines is presented in U.S. Pat. No. 6,695,861.

Referring to FIG. 10, catheter 100 is shown operably coupled to an infusion device 300. Catheter 100 may be connected to infusion device 300 via catheter connector 330. Infusion device 300 shown in FIG. 10 comprises a refill port 310 in fluid communication with a reservoir (not shown) for housing a fluid to be infused to into a subject via catheter 100, which is in fluid communication with reservoir. Infusion device 300 as depicted in FIG. 10 also comprises an injection port 320, which is in fluid communication with catheter. Fluid, e.g. fluid containing therapeutic agent, may be injected into injection port 320, e.g. to deliver a bolus of therapeutic agent. Examples of infusion devices 300 having injection ports 310 in fluid communication with reservoirs and having injection ports 320 are Medtronic, Inc.'s SynchroMed® series of infusion devices. While not shown, it will be understood that infusion device 300 may be any device that is capable of delivering a fluid through catheter 100, such as a syringe, a device having a pump (e.g., osmotic, peristaltic, piston, etc.), an access port, and the like.

Referring to FIG. 11, a programmable infusion device 300, such as Medtronic, Inc.'s SynchroMed® series of infusion devices, is shown implanted in a human. As shown in FIG. 11, distal end 30 of catheter 100 may be inserted into a subject's spinal canal through a lumbar puncture and advanced rostrally through the spinal canal to a desired location. Proximal end 10 of catheter 100 is coupled to infusion device 300, which is typically implanted in the subject at a subcutaneous location. Infusion device 300 comprises a receiver 42 (or transmitter) which is capable of telemetric communication (or any other suitable form of communication) with programmer 400. Programmer 400 may communicate with an implantable infusion device 300 to adjust the amount of therapeutic agent delivered. Communication may be unidirectional; e.g., programmer 400 to infusion device 300, or bi-directional. Generally, programmer 400 is placed over skin in an area where infusion device 300 is implanted to communicate with device 300. While not shown, it will be understood that one or more sensors may be operably coupled to infusion device 300 to alter the rate at which therapeutic agent is delivered. Programmable infusion devices are particularly amenable to alteration of infusion rate via sensors. One advantage of the use of programmable infusion devices over non-programmable devices is that the rate of delivery of therapeutic agent from infusion device 300 may be altered as a patient's condition warrants or to optimize therapeutic efficacy.

In general, it will be understood that catheter 100, or portions thereof, may be made of any material that is compatible with a subject in which catheter 100 is implanted and with fluid to be delivered through catheter 100. Material selection for the catheter may be based on mechanical properties of the tubing, drug stability (changes in the drug due to the catheter material), drug compatibility (changes in the catheter material due to the drug), biostability (changes in the material due to the in vivo environment), biocompatibility (effects of the material on the patient), and the like. Generally catheter 100 or portions thereof will be made of polymeric material such as silicone, polyurethane, polyethylene, polypropylene, or the like. If polypeptides are to be delivered via catheter 100, it may be desirable to use polymeric materials other than silicone, as the polypeptide may adhere to or be absorbed into the silicone or may be degraded.

Thus, embodiments of the INTRATHECAL CATHETER are disclosed. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.

Claims

1. An intrathecal catheter for delivering fluid to, or withdrawing fluid from, the cerebrospinal fluid compartment of a subject, the catheter comprising:

a proximal end;

a distal portion having an outer diameter of about 1 mm or less, a bending stiffness of between about 0.0005 pounds-inch squared to about 0.002 pounds-inch squared, and a distal end;

a delivery region located between the proximal end and the distal end; and

a lumen extending from the proximal end to the delivery region,

wherein the material forming the distal portion of the catheter has sufficient hoop strength to resist collapsing of the lumen when implanted in the cerebrospinal fluid compartment.

2. The catheter of claim 1, further comprising a visualization marker disposed in or about the distal portion in proximity to the delivery region.

3. The catheter of claim 1, wherein the length of the catheter from the proximal end to the delivery region is about 40 cm or more.

4. The catheter of claim 1, wherein the distal portion further comprises a coiled structure region.

5. The catheter of claim 4, wherein the delivery region located in the coiled structure region.

6. The catheter of claim 4, wherein the coiled structure region is capable of being straightened upon insertion of a stylet into the lumen of the catheter.

7. The catheter of claim 1, wherein the catheter is formed from a polymeric material.

8. The catheter of claim 1, wherein the catheter is formed from a material comprising polypropylene.

9. The catheter of claim 1, wherein the catheter is formed from a material comprising polyethylene.

10. A kit comprising:

a catheter according to claim 1; and

a stylet having a proximal end, and a distal portion, the distal portion comprising a distal tip and being configured to be slidably disposable in the lumen of the catheter.

11. The kit of claim 10, further comprising a stop mechanism configured to grippingly engage an outer surface of the stylet and to engage the proximal end of the catheter as the stylet is inserted into the lumen of the catheter to prevent the stylet from being advanced into the lumen beyond a point where the distal tip of the stylet extends through the lumen and beyond the delivery region of the catheter.

12. The kit of claim 11, wherein the stop mechanism is capable of being actuated between an open and a closed state, wherein the stop mechanism in the open state is moveable relative to stylet and wherein the stop mechanism in the closed state is configured to grippingly engage the stylet.

13. The kit of claim 10, further comprising a stop mechanism configured to grippingly engage an outer surface of the stylet and to engage the proximal end of the catheter as the stylet is inserted into the lumen of the catheter, wherein the length of stylet from location of stop mechanism to distal tip is less than length of the lumen from proximal end of catheter to delivery region.

14. A system comprising:

a catheter according to claim 1; and

an implantable infusion device operably couplable to the catheter such that fluid is deliverable from the device to a patient via the delivery region of the catheter when the system is implanted in the patient.

15. A catheter comprising:

a proximal end;

a distal portion including a delivery region and a coiled structure region;

one or more tines located proximal to the delivery region and the coiled structure region; and

a lumen extending from the proximal end to the delivery region.

16. The catheter of claim 15, wherein the delivery region is located within the coiled structure region.

17. The catheter of claim 15, wherein the delivery region is located distal to the coiled structure region.

18. The catheter of claim 15, wherein the coiled structure region is capable of being straightened upon insertion of a stylet into the lumen of the catheter.

19. A system comprising:

a catheter according to claim 15; and

an implantable infusion device operably couplable to the catheter such that fluid is deliverable from the device to a patient via the delivery region of the catheter when the system is implanted in the patient.