Patent Application
20050197627
1. Field of the Invention
The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to methods and systems for intraluminal and percutaneous access to body cavities and other target locations.
Catheters, dilators, endoscopes, and other access devices are useful in a very wide variety of diagnostic and therapeutic medical procedures. Such access devices may be introduced through existing body lumens, such as a urethra, a ureter, a blood vessel, a hepatic duct, a cystic duct, a cervical canal, a fallopian tube, and the like, in order to provide an access path from a region external to the patient to a target region within the body. For some target regions, such as blood vessels, at least a portion of the access path will pass transcutaneously and/or through internal tissues in order to reach the body lumen or target region within the body. Such access through solid tissue typically relies on forming a “tissue tract” by passing a stylet, needle, or other penetrating element through the tissue. Once such access is provided, a wide variety of diagnostic techniques may be performed, such as specimen collection, biopsy, and the like. Alternatively, therapeutic procedures, such as endoscopic procedures, drainage procedures, interventional procedures, and the like, may also be performed.
Passage of such access devices through body lumens and/or through tissue tracts in solid tissue presents certain risks and discomfort to the patient. For example, introduction of catheters through the urethra can carry pathogens into the bladder, causing infection. Repeated access through any natural body lumen or tissue tract can also cause trauma to the lumen, placing the patient at risk of injury or infection. Injury to the lumen may also cause bleeding as well as short or long term stricture.
In order to at least partly overcome some of these deficiencies, the use of sheaths or “protective sleeves” has been proposed. For example, in a series of patents assigned to RTC, Inc., of St. Paul, Minn., the use of an everting sleeve initially stored within a catheter to protect the urethra in access procedures is described. The sleeve is attached at its distal end to a ring which can be placed against the entrance to the urethra before the catheter is advanced. As the catheter is advanced, the protective sleeve is pulled from an internal lumen of the catheter and everts around the advancing tip of the catheter so that it is deployed over the urethral wall. Although very promising, the need to evert the sleeve around the blunt tip of the catheter can provide challenges for deployment.
The use of radially expanding sleeves for introducing dilators and other surgical instruments has been proposed in a series of patents originally assigned to Innerdyne Medical, Inc. These patents describe use of a braided tubular sleeve for introducing dilators and other laparoscopic tools. The braid is introduced over a needle, such as an insufflation needle when used in laparoscopic procedures. After introducing the sleeve, the needle is removed, and a dilator introduced through the sleeve to stretch the sleeve and increase the diameter of the sleeve lumen. Use of the sleeve for vascular and other procedures is taught in some of the Innerdyne patents. Although quite useful, particularly for dilation, the Innerdyne braided sleeve has substantial thickness and adds considerably to the deployed diameter of an device through which it is introduced. Such added thickness, high tissue friction, can be a problem, particularly in procedures such as urethral access, where a low profile is desired.
For these reasons, it would be desirable to provide additional and improved methods and systems for introducing diagnostic and therapeutic devices through body lumens and tissue tracts. In particular, it would be desirable to provide improved protective sleeves and methods for deploying protective sleeves during the introduction of such diagnostic and therapeutic devices. For example, it would be desirable to provide sleeves which could be deployed over a device during introduction of that device through a body lumen, where the sleeve does not have to evert about a distal end of the device during deployment. It would be further desirable to provide such sleeves having a very thin wall thickness so that any increase in overall profile of the apparatus being introduced is minimized. It would be further desirable to provide protective sleeves for covering medical access devices, where the sleeves can be maintained in a sterile environment at all times up until deployment of the sleeve into the body lumen. At least some of these objectives will be met by the inventions described hereinbelow.
2. Description of the Background Art
The use of an everting sleeve composed of thin, tensilized polytetrafluoroethylene for introducing catheters to body lumens is described in U.S. Pat. Nos. 5,531,717; 5,676,688; 5,711,841; 5,897,535; 6,007,488; 6,240,968; and EP605427B1. The use of braided and other radially expanding sheaths for introducing surgical tools, and other articles is described in U.S. Pat. Nos. 5,431,676; 5,454,790; 5,814,058; 5,836,913; 6,080,174; 6,325,812; and 6,494,893. The use of sleeves for protecting biopsy needles and cannulas is described in U.S. Pat. No. 4,262,677; DE10031661A1; and Woitzik and Kraus (2003) Surg. Endosc. 17:311-314.
The present invention provides methods and systems for accessing target locations within a patient's body. The target locations will often be inside of a body cavity or organ but can also be within solid tissue. Exemplary target locations include sites to be diagnosed, such as by biopsy, aspiration, imaging, chemically analysis and the like. Alternatively, the target locations may be intended for therapeutic treatment, such as drainage, drug delivery, ablation, excision, thermal treatment, photodynamic therapy, and the like. Access to the target location will usually be at least partly through a natural body lumen, such as a urethra, a ureter, a blood vessel, a hepatic duct, a cystic duct, a cervical canal, a fallopian tube, or the like. Additionally or alternatively, the access can be wholly or partly through solid tissue. To provide access through solid tissue, it will be necessary to form a tissue tract either before or at the same time as introducing the protective sleeve of the present invention, as will be described in detail below. An exemplary technique employing the protective sleeves of the present invention will be described in connection with transurethral access of the bladder, but it will be appreciated that the principles and embodiments of the present invention may be applied to a much wider variety of target locations and access routes.
In a first aspect, the present invention provides a method for deploying a sleeve through a body lumen. A furled sleeve is first positioned at a luminal entry point where a leading edge of the sleeve is coupled to an advancement member. The advancement member can be any one of a variety of conventional or novel introducing tools, including guidewires, catheters, probes, wires, cannulae, and the like, and the sleeve will typically but not necessarily have an inside diameter which is greater than the outside diameter of the advancement member, typically being at least 25% larger and often at least 50% or more larger. The advancement member may be provided separately from the furled sleeve, in which case the method may further comprise attaching the advancement member to the sleeve prior to unfurling. Alternatively, the advancement member may be pre-attached to the sleeve and sterilely packaged in that condition. In either case, the advancement member is advanced into a desired body lumen, either a natural lumen or a tissue tract, whereby the sleeve is unfurled and deployed into the lumen. Exemplary natural body lumens include a urethra, a ureter, a blood vessel, a hepatic duct, a cystic duct, a cervical canal, a fallopian tube, and the like. In contrast, a tissue tract may be formed using an advancement member having a self-penetrating tip, such as a sharpened tip, an electrosurgical tip, an ultrasonic tip, or the like. The advancement member may thus be passed through solid tissue to either the desired target location or to another body lumen, duct, or cavity, which in turn leads to the target location. The target location may be itself present in solid tissue or within a body cavity, lumen, or duct. In some instances, it will be desirable to pre-form a tissue tract, e.g. using a stylet, an electrosurgical probe, or the like, prior to advancing the advancement member therethrough to deploy the protective sleeve of the present invention.
In a second aspect, the present invention provides methods for accessing a body lumen of a patient. The method comprises providing a furled sleeve and advancing one end of the sleeve through the body lumen causing the sleeve to progressively unfurl. A separate access member is then introduced through an axial passage of the unfurled sleeve while the sleeve remains in the body lumen. Typically, the access member will be a catheter, a dilator, a sheath/stylet combination, an endoscope, or other conventional diagnostic or therapeutic tool. The access member will often be introduced over an advancement member which is used to advance the sleeve through the body lumen, such as a guidewire, small diameter catheter, wire, probe, or the like. The method will be used to access target locations through natural body lumens and tissue tracts, generally as described above with respect to the first method of the present invention. The protective sleeve will have at least one axial passage therethrough, and may optionally have two axial passages, three axial passages, or more. Usually, the advancement member will be positioned in one of the axial passages, where the access member may then be introduced through the same axial passage or through an alternative axial passage if others exist. Alternatively, the advancement member could be attached at the distal end of the protective sleeve but be located over the exterior of the sleeve. In all instances, the advancement member could include a loop, ring, or other expansive element at its distal end which is capable of opening the distal ends of the axial passage(s).
In a third aspect of the present invention, a luminal access system comprises a furled sleeve having at least one axial passage therethrough and an advancement member adapted to couple to a leading edge of the sleeve and to unfurl the sleeve as the advancement member is advanced through a body lumen. The furled sleeve will be positionable at a luminal entry point, such as a natural body orifice or intended site for percutaneous access, and the advancement member may be advanced through the furled sleeve in order to deploy the sleeve into a body and lumen or a tissue tract being created. A preferred furled sleeve will be present in a storage chamber which maintains the sleeve in a sterile and protected condition prior to use. The sleeve may be in a rolled configuration, a folded configuration (typically accordion-like folds), or otherwise reduced in size to minimize the size of the furled sleeve enclosure. The storage chamber will have a slot for passing of the sleeve from the interior to the exterior. Usually, the storage chamber will also have an axial passage to permit advancement of the advancement member through the chamber in order to deploy the sleeve.
Preferred protective sleeves are polymeric tubes, particularly thin-walled polymeric tubes made from a lubricious polymer or a polymer which may be lubricated on at least one side. The polymeric tube typically has a length in the range from 5 cm to 50 cm, preferably from 10 cm to 25 cm, an inner diameter (for a single lumen) in the range from 2 mm to 12 mm, preferably in the range from 2 mm to 6 mm, and a wall thickness in the range from 0.01 mm to 0.05 mm, preferably from 0.08 mm to 0.13 mm. Preferred polymers for the polymeric tube include polytetrafluoroethylene (PTFE), polyethylene (PE), perfluoroalkoxy (PFA), polyurethane (PU), perfluoromethylvinylether (MFA), perfluoropropylvinylether (PPVE), and the like. A preferred polymer comprises a tensilized PTFE/PPVE copolymer.
The advancement member may be pre-attached to the distal end of the protective sleeve or may be adapted to permit attachment immediately prior to the deployment. In either case, it will often be desirable to provide attachment that is frangible so that the sleeve can be detached from the advancement member, e.g. by advancement of an access member over the advancement member, such as advancement of a dilator over a guidewire advancement device. The advancement member will often have an axial lumen through at least a portion thereof to receive a catheter or guidewire.
Referring now to
In any case, advancement of the advancement member 12 in an axial direction (to the right in
After the advancement member 14 has been passed through the body lumen or tissue tract to a desired target location, a separate access member, such as a catheter, dilator, sheath/dilator, endoscope, or the like, may be passed through the sleeve 10 (often also widening the body lumen simultaneously) and optionally over the advancement member 12 which may be, for example, a guidewire. As illustrated in
As illustrated in
In
In
Referring now to
Use of the methods and devices of the present invention for accessing a bladder B through a urethra U is shown in FIGS. 6A-D. Prior to introduction, the urethra U is generally collapsed and non-dilated as shown in
While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.
