Patent Description:
Sheaths comprise temporary, external, conduit extensions that facilitate repair of the internal, permanent conduit from the inside. These conduit extensions communicate most commonly through the vascular system, but also can act as conduits between the external environment and any internal plumbing system, e.g. arterial, venous, biliary, portal venous, gastrointestinal tract, renal collecting system, excluded aortic aneurysm sac, central canal/thecal sac/epidural space. In this way, large incisions are avoided, recovery is quicker, treatment is less expensive versus surgery, and the life span of the veins and arteries used is prolonged. Generally, one to two sheaths are employed during each intervention.

<CIT> and <CIT> disclose two exemplary prior art vascular access sheath assemblies.

A sheath is described that is suitable for use in a variety of medical procedures. In one or more implementations, the sheath includes a shunt member, and a curvable portion. The curvable portion may be configured in various orientations to facilitate an intervention, such as a hemodialysis intervention, or the like, by an operator. The curvable portion may be configured to bend between a substantially straight configuration and a curved configuration. In implementations, the sheath may be configured to have detachable and/or interchangeable components (e.g., shunt member, curvable portion, etc.).

Particular embodiments are defined in the dependent claims.

Existing sheaths are straight or have internal curves (i.e., curves within the patient). Internal curves aid in the effectiveness for certain procedures in the vascular system, but have no significant function in dialysis intervention/repair. Although effective in their purpose, existing sheaths are hampered by limitations.

One limitation is due to the shape, flow, and direction of the permanent vascular conduit, such as an arterial-venous fistula (AVF) or arterial-venous graft (AVG). The direction of flow is from the artery to the vein, either directly or through a graft. The arterial limb of the AVF travels from proximal to distal, while the venous limb travels from distal to proximal. Therefore, access through these sheaths may occur from two separate and opposite directions, which may produce technical difficulties due to the fact that the primary operator cannot be positioned in two polar opposite directions at the same time. Treatment from one direction also can be hindered by the proximity of the sheath in relation to the rest of the patient's body impeding the ease of work.

In addition, in order to repair AVFs via percutaneous or other minimally invasive techniques, angiography machines are required. Angiography machines utilize medical imaging techniques such as radiation to visualize the blood vessels and conduits of the patient. Radiation exposure is a concern to operators, who often perform multiple procedures in a given day. Moreover, interventional, minimally invasive repair of vascular, genitourinary tract, gastrointestinal tract, biliary, portal venous, musculoskeletal and central nervous system procedures may also expose the operator and patient to increased radiation exposure depending on technical difficulties of location of percutaneous/minimally invasive access of the conduit system of the patient in relation to the angiography machine.

In one implementation, the present disclosure allows for improved hemodialysis access intervention, which allows for dialysis access intervention of both sides (limbs) of the dialysis conduit from the same operator position. Furthermore, the present disclosure may allow an operator, as well as the patient, to receive lower radiation exposure as well as decrease the total time of the intervention procedure.

Therefore, a sheath with an external curvable portion is disclosed. The sheath allows for dialysis access intervention of both sides (limbs) of a dialysis conduit from the same operator position. In one or more implementations, a sheath includes a detachable shunt member, and a detachable curvable portion. The curvable portion is configured to bend between a substantially straight configuration and a curved configuration to facilitate hemodialysis intervention by an operator. In an implementation, the curvable portion may retain a <NUM>° curve when the curvable portion is positioned in the curved configuration. In the curved configuration, the curvable portion may be held in position via a clasp. The clasp is configured to hold the curvable portion in the curved configuration. In an implementation, the clasp is coupled to at least one of a first end of the curvable portion or the second end of the curvable portion. Moreover, the clasp may be selectively coupled at a position proximate to the other of the first end of the curvable portion and the second end of the curvable portion. In yet another implementation, the curvable portion may comprise a semi-rigid material. In this implementation, the curvable portion retains its curved configuration once the operator/technician has positioned the sheath in the desired curved configuration.

It is also contemplated that the sheath may also be comprised of detachable components. In an implementation, the shunt member may be comprised of a detachable shunt member. For example, access to an excluded aortic aneurysm with an aneurysm leak may require a longer sheath member (e.g., fifteen (<NUM>) centimeters). The detachable components may be interchangeable with other detachable components adapted for use in the sheath. Moreover, the exterior curvable portion, in conjunction with the detachable components, allows for improved operator/technician access to the patient.

Generally referring to <FIG>, an implementation of a sheath <NUM> configured for hemodialysis access and intervention is illustrated. A detachable shunt member <NUM> may be provided with a dilator <NUM>. The detachable shunt member <NUM> is configured to extend through a perforation in a side wall, or a superficial wall, of an internal patient conduit source (e.g., a blood vessel) and into an anatomical conduit (e.g., the blood vessel) of a patient. The detachable shunt member <NUM> may vary in length depending on the use of shunt member <NUM>. For example, the shunt <NUM> may be about five (<NUM>) centimeters in length. The shunt <NUM> is coupled with a curvable portion <NUM> by a member <NUM>. In an implementation, member <NUM> may be configured as a detachable member <NUM>. Detachable member <NUM> may include a septum (not shown) that is configured to receive other medical devices (i.e., needles, wire, etc.) if detachable curvable portion <NUM> is not required. In a further implementation, member <NUM> may be manufactured as a unitary member with shunt <NUM>. In the unitary configuration, member <NUM> may include a notch <NUM> adapted to receive clasp <NUM>. In an implementation, detachable curvable portion <NUM> may be flexible and is capable of forming a "tennis racket" shape. In another implementation, as illustrated in <FIG>, curvable portion <NUM> may be bendable and semi-rigid to allow the curvable portion <NUM> to retain its curved configuration once an operator/technician has positioned the sheath <NUM> in the desired curved configuration. The sheath <NUM> may be configured to be curvable or bendable between <NUM>° and <NUM>°. The curvable portion <NUM> may be implemented as a tube, or the like. Curvable portion <NUM> may form an arc having a diameter of about two (<NUM>) centimeters to about four (<NUM>) centimeters. In a specific implementation, the curvable portion <NUM> may form an arc having a diameter of about three (<NUM>) centimeters. In example implementations, the sheaths <NUM> may be about five (<NUM>) to about eight (<NUM>) French in external diameter. However, the overall length of sheath <NUM>, the dimensions of the external curve of detachable curvable portion <NUM>, the degree of curve of detachable curvable portion <NUM>, and the length of internal (i.e., shunt <NUM>, etc.) and external (curvable portion <NUM>, etc.) portions of sheath <NUM> can vary specific to type and location of the intervention.

A tube <NUM> may be attached to a septum hub <NUM> having an introducer dilator <NUM> and a detachable <NUM>-way, large bore, stop cock <NUM>. In an implementation, the lumen (not shown) of the exposed end of the screwable tubing <NUM> is comparable in size to the respective lumen of a large bore dialysis sheath. Tube <NUM> is utilized for injection of contrast, fluids, and medications. Tube <NUM> may also be utilized to aspirate clot and blood and allow for improved suction/aspiration of the thrombus/clot. In an implementation, the tube <NUM> is configured to have a forty-five (<NUM>) degree angle. However, it is contemplated that the tubing <NUM> may be implemented in various other configurations (e.g., to have different angles of curvature) without departing from the spirit of the disclosure. Septum hub <NUM> is configured to receive one or more interventional tools and is coupled to curvable portion <NUM> by a junction <NUM>. Junction <NUM> may be coupled to a clasp <NUM> at a junction <NUM>. In one or more implementations, junction <NUM> may comprise a medical grade material or the like. For instance, junction <NUM> may be manufactured from a medical grade plastic or the like. Moreover, junction <NUM> is configured to stabilize curvable portion <NUM>. Junction <NUM> provides connective functionality to clasp <NUM>. For example, clasp <NUM> may couple to junction <NUM>, which allows clasp <NUM> to couple to junction <NUM>. While <FIG>, <FIG>, and <FIG> illustrate clasp <NUM> coupled to notch <NUM>, clasp <NUM> may be configured to be selectively coupled to shunt <NUM>, detachable member <NUM>, or the like. When coupled to notch <NUM>, or the like, clasp <NUM> holds the device in a position such that septum hub <NUM> is oriented in a direction opposite from that of shunt <NUM> or a variation of this direction. When the clasp <NUM> is disengaged from shunt <NUM>, the flexible nature of curvable portion <NUM> allows septum hub <NUM> to be arranged generally in-line with shunt <NUM>. In another implementation, septum hub <NUM> may be arranged in a variety of positions and at angles between <NUM>° (i.e. in-line) and <NUM>° (or possibly more if required) relative to shunt <NUM>. In yet another implementation, septum hub <NUM> may be exchanged with other hub adaptors (not shown) depending on operator/technician, plumbing position, and interventional needs. Moreover, in an implementation, the detachability and interchangeability of sheath <NUM> components may allow increased stiffness of the detachable curvable, external portion <NUM>.

While sheath <NUM> is shown as a complete sheath, sheath <NUM> could be used in conjunction with existing sheaths and sheath components. As described above, sheath <NUM> may also be comprised of separate, detachable components at detachable member <NUM>. In such implementations, sheath <NUM> could be used with existing components that allow for curvatures internal to the patient. For example, the internal, distal, and proximal, curved components of sheath <NUM> can be interchanged with currently available sheaths if the locking systems match. In addition, existing sheath components may be used with portions of sheath <NUM> to provide a sheath that may be selectively configured to provide a <NUM>° curve. In such implementations, curvable portion <NUM>, detachable member <NUM>, junction <NUM>, and clasp <NUM> may be provided as a single unit that would be used to retrofit an existing sheath design.

In selecting sheathing for curvable portion <NUM>, consideration for the largest internal diameter with a solid, kink resistant material is given. For example, curvable portion <NUM> may be comprised of a nitinol wire impregnated plastic sheath. Both coiled and cell design impregnated sheaths may be useful, though coil designs are likely preferable to maintain flexibility. Conventional portions of sheath may be manufactured from materials normally used for such items. When attachable/detachable components are utilized, stiffness of components may increase.

The sheath <NUM> should also have an acute change in caliber at the proximal portion of shunt <NUM>, limiting sheath migration, as well as having a notch <NUM> within this diameter enlargement. The notch <NUM> may act as an attachment for a clasp <NUM>, locking the two parallel ends of the sheath <NUM>. The clasp <NUM> will allow stability of sheath <NUM> and will counter against the movements of interventional tools within the sheath <NUM> and internal vasculature.

As illustrated in <FIG> and <FIG>, clasp <NUM> is shown extending from junction <NUM> where it is coupled at junction <NUM>. Clasp <NUM> comprises a shank portion <NUM> and a clasping portion <NUM>. In an implementation, the clasping portion <NUM> may have a generally arcuate configuration or the like. Clasping portion <NUM> extends at least partially about detachable member <NUM> and may engage notch <NUM> to secure sheath <NUM> in a "closed" (i.e., curved) configuration. In this sense, the "closed" configuration is one in which septum hub <NUM> is oriented in a direction generally opposed to the direction of shunt <NUM> and clasp <NUM> engages detachable member <NUM>. Moreover, when the sheath <NUM> is in the "closed" configuration, first end <NUM> of the curvable portion <NUM> is proximate to second end <NUM> of the curvable portion <NUM>. This configuration allows an operator or technician to access a vascular conduit through sheath <NUM>, and, in those situations where the vascular conduit may be accessed from a position proximate to the patient's torso, head, or abdomen, the operator may be positioned away from those parts of the patient.

Referring to <FIG>, sheath <NUM> is in an "open" position where clasp <NUM> is disengaged from detachable member <NUM>. While it is shown that the "open" position may be semi-curved, it is understood that the curvable portion <NUM> may retain a substantially straight configuration. For example, the curvable portion <NUM> may be positioned by an operator so that the curvable portion <NUM> retains a substantially straight configuration. In the substantially straight configuration, the first end <NUM> may be linearly distal to the second end <NUM>. Moreover, member <NUM> of sheath <NUM> proximate to septum hub <NUM> may be more freely manipulated by an operator or technician due to the flexibility of curvable portion <NUM>. For example, sheath <NUM> may be used in a position that places the flow at septum hub <NUM> perpendicular to that of shunt <NUM> (as illustrated in <FIG>), which allows the operator or technician to utilize an angiography machine to visualize vascular structures in the patient while the operator or technician remains outside the radiation field produced by the angiography machine. The sheath <NUM> may eliminate or reduce possible exposure of the operator or technician to radiation, while allowing for the simultaneous use of tools that may be inserted through septum hub <NUM> to access the vascular conduit within the patient.

<FIG> illustrate one or more sheath(s) <NUM> utilized in a medical environment. For example, the sheath <NUM> disclosed herein may be readily useable in hemodialysis intervention. Other potential uses include antegrade percutaneous arterial intervention of the common femoral artery, or similar accessible vessel, whereby an operator can work along side of extremity without working near a patient's abdomen, chest, and head. Moreover, the sheath <NUM> may also be useful for treatment of renal collecting system intervention. The sheath <NUM> also has potential for patients with ureteral strictures, status post cystectomy, and in urinary conduit formation. Moreover, sheath <NUM> may be utilized in conjunction with the treatment of the biliary tree, portal venous system, gastrointesintal tract, and spinal canal/thecal sac.

Additional uses for the sheath <NUM> may be realized with the addition of exhalable or detachable appendages. For example, a larger curvable portion <NUM> may be used for larger patients receiving lower extremity intervention. Other adaptations include the use of a Toughey-Borst fitting to allow the simultaneous introduction of a fluid while using a guide wire during catheterization. A double lumen or bifurcated sheath may be used for therapy requiring two wires and access sites, from one approach. A larger internal diameter may be used to create larger communication for a suction thrombectomy.

In some implementations, a kit may comprise a single sterile prepackaged assortment of sheath components. Such kits may include a plurality of curvable portions <NUM> being of different lengths and/or diameters to allow for the physician to customize the sheath <NUM> for a particular patient or procedure. For example, a longer curvable portion <NUM> may be used to facilitate antegrade access to the femoral artery for peripheral vascular disease treatment of the ipsilateral extremity, and give the physician the ability to position him/herself in the area of the patient's legs rather than by the patient's abdomen. The longer curvable portion <NUM> may be curved around the patient's leg and towards the feet to provide the physician and patient with greater comfort during a procedure.

In some implementations, a kit may include a portion of sheath configured to provide an arcuate portion (similar to curvable portion <NUM>) with conventional couplers. The kit would allow for the modification of existing sheaths to an adjustable sheath with the ability to provide a bend of about <NUM>°. For example, the arcuate portion may be configured to couple to an inductor (not shown) of an existing sheath (not shown). Moreover, the kit would allow an interventionist to modify a sheath system after placement in the patient if it is decided that a curved sheath would be advantageous.

While sheath <NUM> is in use, the physician or other operator may exert force to advance a catheter, needle, guide wire, or other device through the sheath <NUM>. When the sheath <NUM> is arranged into a <NUM>° curve, this force acts to pull the sheath out of the patient at the access point. Accordingly, it would be advantageous to provide a stabilizing means for sheath <NUM> while in use. Such a means may include an adhesive patch (not shown) for securing the sheath to the patient at a point proximate to the access point. Such patches include the STATLOCK available from C. of Murray Hill, New Jersey. Other stabilization devices may include external devices such as stabilizing boards that are coupled to the patient and sheath <NUM> by straps, clasps or other conventional coupling means. Sheath <NUM> may also be provided with a stabilizing portion that includes apertures for the placement of sutures to secure sheath <NUM> to the patient.

Sheath <NUM> may further include an anti-backflow exchange wire, which is illustrated in <FIG>. The anti-backflow exchange wire is configured to block backflow that may occur when an operator/technician removes back end components of sheath <NUM>. Thus, an operator/technician may interchange the sheath's <NUM> back end components (e.g. converting from a straight, short <NUM> sheath, to a <NUM> degree curved, tennis racket shaped sheath, and so forth) with minimal to no leakage when utilizing the anti-backflow exchange wire. A septum (e.g., a valve or seal) may attach to the wire (such as a <NUM> (<NUM> inch) or a <NUM> (<NUM> inch) wire) and configured to block flow within the sheath <NUM>. The septum may be configured to move within sheath <NUM> while maintaining a seal against the interior wall of sheath <NUM>. The septum may be fixed in relation to the wire. In use the septum moves with the wire as it is advanced through the sheath and prevent the backflow of blood or other fluids. When the wire is retracted, the septum moves with the wire. This can be done to allow completion of a procedure while minimizing the release of fluids through sheath <NUM> out of the patient that could obscure the view of the operator or cause couplings to become stuck. Moreover, sheath <NUM> may be used with a variety of catheterization devices including guide wires.

Referring to <FIG>, sheath section <NUM> has an exterior wall <NUM> and an interior wall <NUM>. Septum <NUM> is sized to seal the interior diameter of sheath section <NUM> while allowing septum <NUM> to slide relative to interior wall <NUM>. Septum <NUM> includes a disc portion <NUM> and two lugs <NUM> and <NUM>. Lugs <NUM> and <NUM> may be provided with a longitudinal aperture <NUM> for receiving wire <NUM>. Disc <NUM> may have an aperture coaxial with aperture <NUM>. Disc <NUM> may also be punctured when wire <NUM> is passed through the aperture <NUM> through lugs <NUM> and <NUM>. Lugs <NUM> and <NUM> may be separate parts from disc <NUM>. Lugs <NUM>, <NUM>, and disc <NUM> may also be formed as a single unitary body to provide septum <NUM>. Wire <NUM> may be passed through septum <NUM> prior to placing septum <NUM> in sheath section <NUM>. The friction between wire <NUM> and septum <NUM> may be sufficiently greater than the friction between septum <NUM> and interior wall <NUM> such that once septum <NUM> is placed in sheath section <NUM>, the force required to move septum <NUM> relative to interior wall <NUM> is greater than the force required to move wire <NUM> relative to septum <NUM>. Lugs <NUM> and <NUM> with passage <NUM> provide a greatly increased surface area over which septum <NUM> contacts wire <NUM> compared to the contact area provided by disc <NUM>. Such a configuration allows septum <NUM> to move within sheath section <NUM> while remaining static with respect to wire <NUM> and maintaining a seal against the backflow of fluids.

Claim 1:
A sheath (<NUM>) comprising:
a detachable shunt member (<NUM>) comprising a coupling member (<NUM>), the detachable shunt member (<NUM>) configured to extend through a perforation in a side wall of an internal patient conduit source and into an anatomical conduit;
a detachable junction (<NUM>) configured to receive an interventional tool;
a curvable portion (<NUM>) having
a first end (<NUM>) configured to be detachably coupled to the coupling member (<NUM>) of the detachable shunt member (<NUM>) and
a second end (<NUM>) configured to be detachably coupled to the detachable junction (<NUM>),
wherein the curvable portion (<NUM>) is configured to bend between a curved configuration and a substantially straight configuration where the first end (<NUM>) is linearly distal to the second end (<NUM>);
a septum hub (<NUM>) configured to be detachably coupled to the second end of the curvable portion (<NUM>) by the detachable junction (<NUM>), wherein the septum hub (<NUM>) is configured to receive the interventional tool inserted therethrough allowing the interventional tool to be advanced through the sheath (<NUM>) to access the anatomical conduit.