Steerable introducer sheath assembly

Abstract

The present application discloses an introducer sheath assembly, which has a handle portion including a distal end and a proximal end, and an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device, a guidewire lumen configured to slidably receive a corresponding guidewire, and at least one steering cable, the at least one steering cable being arranged in at least one steering cable lumen arranged radially outward from the device lumen, and the handle portion including at least one steering assembly for modifying the tension of at least one of the at least one steering cables.

Description

[0001] Citations of Related Applications

[0002] This application claims the benefit of priority to Chinese invention patent application No. 201810146156.9 filed on February 12, 2018, and claims the benefit of priority to Chinese utility model application No. 201820252716.4 filed on February 12, 2018. The entire contents of the foregoing applications are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to medical devices, and more particularly to vascular access sheaths and catheters. Background Art

[0004] Increasingly, minimally invasive catheter-based therapies are being developed that allow physicians to provide therapy to patients whose existing comorbidities preclude them from undergoing needed but more invasive surgical procedures. Over the past 30 years or so, catheter-based procedures involving puncturing / crossing the interatrial septum, such as cardiac ablations and balloon valvuloplasty, have become commonplace. Over the past 5 to 10 years, new structural heart procedures, such as transcatheter valve repair / replacement and left atrial appendage occlusion, have received regulatory approval and have become increasingly common procedures in cardiac catheterization laboratories or hybrid operating rooms. With the advent of these technologies, the need for structural heart interventionists (specialized physicians who perform these types of procedures) to engage and cross the interatrial septum in the heart has also increased.

[0005] Historically, due to the prevalence of cardiac ablation procedures that require crossing the atrial septum, crossing the septum has been the purview of pediatric cardiologists or electrophysiologists. However, interventional cardiologists are increasingly beginning to provide therapies to the left side of the heart, and the demand to puncture the atrial septum and provide these new therapies is increasing. Unfortunately, many of these interventional cardiologists do not perform transseptal punctures with enough regularity to become proficient at it. For these left-sided procedures, it is not enough to simply puncture the atrial septum safely and enter the left side of the heart. These new techniques require a very specific and safe position when crossing the atrial septum. In addition, crossing the atrial septum has historically been guided by fluoroscopy (X-ray) and more recently by echocardiographic ultrasound (intracardiac echocardiography, transesophageal echocardiography, or transthoracic echocardiography). Fluoroscopy has a limited role due to its limited ability to image soft tissues (such as the atrial septum). Therefore, echocardiography is increasingly relied upon to guide these types of procedures.

[0006] Therefore, it is desirable to provide these newly developed structural heart interventionists with a tool to help them safely and accurately cross the atrial septum. Preferably, these tools may have features that facilitate accurate positioning of vascular sheaths, catheters, and other instruments for catheter-based therapies, including transseptal procedures. Such tools may also include features that may increase their usefulness in echocardiographic imaging and may enhance echocardiographic information or facilitate certain modalities of echocardiography for image guidance that may otherwise not be available.

[0007] The present invention recognizes and addresses the concerns of prior art configurations and methods. Summary of the invention

[0008] 1. A guide sheath assembly, wherein a handle portion includes a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device, a first steering cable lumen, a second steering cable lumen, and a third steering cable lumen, and a first steering cable attached to the distal end of the introducer sheath and disposed in the first steering cable lumen, a second steering cable attached to the distal end of the introducer sheath and disposed in the second steering cable lumen, and a third steering cable attached to the distal end of the introducer sheath and disposed in the third steering cable lumen, wherein the first steering cable lumen, the second steering cable lumen, and the third steering cable lumen are disposed radially outward from the device lumen, wherein the first steering cable lumen and the second steering cable lumen are located on opposite sides of a vertical plane extending through the device lumen and the third cable lumen; and A first steering assembly in the handle portion, which includes an element to which the proximal end of the first steering cable is attached and an element to which the proximal end of the second steering cable is attached; a first steering rod, which is disposed on the outer surface of the handle portion and attached to the first end of the first steering column, wherein the first steering column has a second end engaged with the first steering assembly, so that rotating the steering rod about the longitudinal axis of the first steering column causes the first steering assembly to simultaneously modify the tension in the first steering cable and the second steering cable; a second steering assembly disposed in the handle portion, to which the proximal end of the third steering cable is attached; and a second steering rod, which is disposed on the outer surface of the handle portion and attached to the first end of the second steering column, wherein the second steering column has a second end engaged with the second steering assembly, so that rotating the steering rod about the longitudinal axis of the second steering column causes the second steering assembly to change the tension in the third steering cable.

[0009] Another embodiment of the guide sheath assembly according to the present disclosure includes a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device, a first steering cable lumen, a second steering cable lumen, and a third steering cable lumen, as well as a first steering cable attached to the distal end of the introducer sheath and disposed in the first steering cable lumen, a second steering cable attached to the distal end of the introducer sheath and disposed in the second steering cable lumen, a third steering cable attached to the distal end of the introducer sheath and disposed in the third steering cable lumen, and a fourth steering cable attached to the distal end of the introducer sheath and disposed in the fourth steering cable lumen, wherein the first steering cable lumen, the second steering cable lumen, the third steering cable lumen, and the fourth steering cable lumen are extended from the device lumen to the proximal end of the guide sheath. The inner cavity is arranged radially outward, wherein the first steering cable inner cavity and the second steering cable inner cavity are located on opposite sides of a vertical plane in which the longitudinal center axis of the guide sheath is located, and the third steering cable inner cavity and the fourth steering cable inner cavity are located on opposite sides of a horizontal plane in which the longitudinal center axis of the guide sheath is located; a first steering assembly arranged in the handle portion, which includes an element to which the proximal end of the first steering cable is attached and an element to which the proximal end of the second steering cable is attached; and a second steering assembly arranged in the handle portion, which includes an element to which the proximal end of the third steering cable is attached and an element to which the proximal end of the fourth steering cable is attached; wherein the first steering assembly can be manipulated to simultaneously modify the tension in the first steering cable and the second steering cable, and the second steering assembly can be manipulated to simultaneously change the tension in the third steering cable and the fourth steering cable.

[0010] Another embodiment of the guide sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including: a device lumen configured to slidably receive a corresponding device, at least one steering cable lumen disposed radially outward from the device lumen, at least one steering cable attached to the distal end of the introducer sheath, disposed in at least one steering cable lumen, and engaged with a steering assembly disposed in the handle portion; one or more steering rods disposed on an outer surface of the handle portion and attached to a first end of a steering column, wherein the steering column has a second end engaged with the steering assembly such that rotating the steering rod about the longitudinal axis of the steering column causes the steering assembly to change the tension in at least one steering cable; and wherein at least one steering rod is directly or indirectly engaged with the surface of the handle portion in a manner that limits the extent to which the steering rod can rotate about the longitudinal axis of the steering column.

[0011] Another embodiment of the introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including: a device lumen configured to slidably receive a corresponding device, at least one steering cable lumen disposed radially outward from the device lumen, at least one steering cable attached to the distal end of the introducer sheath, disposed in at least one steering cable lumen, and engaged with a steering assembly disposed in the handle portion; one or more steering rods disposed on an outer surface of the handle portion and attached to a first end of a steering column, wherein the steering column has a second end engaged with the steering assembly so that rotating the steering rod about a longitudinal axis of the steering column causes the steering assembly to modify the tension in at least one steering cable; and wherein the engagement between at least one steering rod and the outer surface of the handle portion is regulated by a dome cover that at least partially surrounds the steering rod, wherein the dome cover is seated in a correspondingly shaped recess in the outer surface of the handle.

[0012] Another embodiment of an introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including: a device lumen configured to slidably receive a corresponding device, at least two steering cable lumens disposed radially outward from the device lumen, at least two steering cables attached to the distal end of the introducer sheath and disposed in the at least two steering cable lumens; a first steering assembly disposed in the handle portion, comprising an element to which the proximal end of at least one of the at least two steering cables is attached; and a second steering assembly disposed in the handle portion, comprising an element to which the proximal end of at least one of the at least two steering cables is attached; wherein the first steering assembly can be manipulated to modify the tension in the steering cable attached thereto, and the second steering assembly can be manipulated to modify the tension in the steering cable attached thereto; and a slack removal assembly for removing excess slack from at least one of the steering cables attached to at least one of the other steering assemblies when the steering assembly is manipulated to change the tension in at least one steering cable attached thereto.

[0013] Another embodiment of an introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including: a device lumen configured to slidably receive a corresponding device; a device locking assembly disposed at a rear end of the housing portion, comprising a device locking rod, the device locking rod defining an axially extending hole, the hole being identified as slidably receiving a corresponding device, the device locking rod being axially movable relative to the handle portion; a clamp disposed on the device locking rod, the clamp being selectively positioned in a locked position and an unlocked position, in which the corresponding device is axially fixed relative to the device locking rod, and in which the corresponding device is slidable within the axially extending hole of the device locking rod, wherein the device locking assembly also includes an advancement knob that is axially fixed and rotatable relative to the handle portion of the body portion, wherein the advancement knob also includes a threaded hole correspondingly threadedly connected to an outer surface of the device locking rod, the device locking rod being threadedly engaged with the threaded hole of the advancement knob; and wherein the device locking rod is also engaged with a rod guide seated in the handle portion so that the locking rod is prevented from rotating when the knob is rotated. This embodiment may also include features that facilitate injection molding manufacturing techniques, including parallel, interrupted planes in the external threads on the outer surface of the device locking rod, and an advancement knob, wherein the outwardly projecting members together define a discontinuous radial flange having a radius greater than a radius of a distal orifice in the handle portion, wherein the discontinuous radial flange allows the advancement knob to be rotatably seated and retained within the distal orifice in the handle portion, wherein the flange is mirrored through an opening in the advancement knob.

[0014] Another embodiment of an introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device, at least one steering cable lumen disposed radially outward from the device lumen, at least one steering cable attached to the distal end of the introducer sheath, disposed within the at least one steering cable lumen, and engaged with a steering assembly disposed in the handle portion, wherein the steering assembly is capable of modifying the tension in at least one steering cable; and a torque transfer lock that prevents the introducer sheath from rotating about a longitudinal center axis when the steering assembly is used to modify the tension in at least one steering cable. The torque transfer lock may also include a hollow post having an inner diameter sufficient to encompass the radial diameter of the introducer sheath, and at least one proximal structure capable of engaging with at least one corresponding structure extending from the face of the handle portion.

[0015] Another embodiment of an introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device; and an orifice in the handle portion, the orifice allowing a user to visualize the position of receiving the corresponding device into the device lumen of the introducer sheath, and may also include a corresponding device including a marking that can be visualized through the orifice to provide the user with an indication of the extent to which the corresponding device has been inserted into the device lumen of the introducer sheath.

[0016] Another embodiment of an introducer sheath assembly according to the present disclosure includes: a handle portion having a distal end and a proximal end; an introducer sheath extending outward from the distal end of the handle portion, the introducer sheath including a device lumen configured to slidably receive a corresponding device; wherein the corresponding device includes one or more modifications to improve ultrasound visualization. In certain such embodiments, the corresponding device is a dilator having a hollow axial hole, the hollow axial hole including modifications to improve ultrasound visualization located on the inner surface of the hollow axial hole. For example, such a dilator may include at least one linear groove extending parallel to the longitudinal center axis of the dilator, and as a further example, may include at least one linear groove having a width of about 0.012 inches and a depth of at most about 0.003 inches, wherein in certain embodiments, the total length of the groove is about 0.375 inches, and in certain other embodiments, the groove consists of a continuous step portion having a length of about 0.0625 inches. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0018] A complete and enabling disclosure of the present invention, including the best mode thereof, is set forth in this specification with reference to the accompanying drawings, in which:

[0019] Figure 1A is a top perspective view of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0020] Figure 1B Provided are top, bottom, and side views of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0021] Figure 1C A top view of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0022] Figure 1D A side view of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0023] Figure 2A is a partial bottom view of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure, wherein a bottom portion of the handle housing is removed to allow visualization of internal components;

[0024] Figure 2B Provided are distal, rear, side, and perspective views of a distal cap of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0025] Figure 2C Provided are distal, rear, and perspective views of an advancement knob of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0026] Figure 2D is a partial bottom view of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure, wherein a bottom portion of the handle housing is removed to allow visualization of internal components;

[0027] Figure 3A A cross-sectional view of a "quad-lumen" introducer sheath for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0028] Figure 3B A cross-sectional view of a "five-lumen" introducer sheath for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0029] Figure 4A An exploded view of a torque transfer lock for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0030] Figure 4B A cross-sectional view of a torque transfer lock for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0031] Figure 5A Provides perspective and cross-sectional views of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure, with an inset showing additional cross-sectional detail and depicting a steering rod 160 in an "unlocked" position;

[0032] Figure 5B Provides perspective and cross-sectional views of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure, with an inset showing additional cross-sectional detail and depicting the steering rod 160 in a "locked" position;

[0033] Figure 5C A cross-sectional view of the interior of the upper and lower portions of the handle of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0034] Figure 5D Top and perspective views of a handle of a steerable introducer sheath assembly according to embodiments of the present disclosure are provided, wherein the steering rod and associated dome cap are separated and / or rotated relative to the handle;

[0035] Fig. 6A Provided are top, bottom, and side views of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0036] Figure 6B A perspective view of a handle of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided, with elements of a distal housing portion separated to aid in visualization of certain features;

[0037] Figure 6C A top view of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0038] Fig.6D A side view of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided;

[0039] Fig. 7A Provided are perspective views of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure, with a portion of the handle housing removed to allow visualization of the slack relief assembly in both a rest configuration (top view) and a slack removal configuration (bottom view);

[0040] Figure 7B Isolated views of an upper handle portion (left), an isolated slack elimination assembly in a slack removal configuration (center), and an isolated slack elimination assembly in a rest configuration (right) are provided according to an embodiment of the present disclosure;

[0041] Fig. 8A is a top perspective view of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0042] Figure 8B is a side perspective cutaway view of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0043] Figure 8C yes Figure 8B a side perspective cutaway view of a proximal end of a handle portion of a steerable introducer sheath assembly;

[0044] Fig.8D is a side perspective cutaway view of a proximal end of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0045] Fig. 8Eprovides a perspective view of a device locking bar from a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0046] Fig. 9A A detailed view of the distal end of a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided, with a portion of the handle housing removed to allow visualization of internal components;

[0047] Fig. 9B is a cross-sectional view of a proximal end of a handle portion of a steerable introducer sheath assembly according to an embodiment of the present disclosure as viewed from a distal perspective;

[0048] Fig. 9C is a top perspective view of an engagement between a device locking rod and an inner guide component for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure;

[0049] Fig. 10A A cross-sectional view of a dilator instrument for use with a steerable introducer sheath assembly according to an embodiment of the present disclosure is provided; and

[0050] Fig. 10B Ultrasound images obtained during introduction (upper left) and removal (upper right) of a prior art dilator, as well as ultrasound images obtained during introduction (lower left) and removal (lower right) of a dilator according to an embodiment of the present disclosure are provided.

[0051] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention according to the present disclosure. DETAILED DESCRIPTION

[0052] Reference will now be made in detail to certain embodiments of the present invention, examples of which are shown in the accompanying drawings. These embodiments are provided as examples only and should not be construed as limiting the scope of the claimed invention to any particular embodiment. In fact, it will be apparent to those skilled in the art that modifications and variations may be made to the present invention without departing from the scope and spirit of the present invention. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is intended that the present invention covers such modifications and variations that fall within the scope of the recited claims and their equivalents.

[0053] In the description of the steerable introducer sheath embodiments provided herein, the terms "distal" and "proximal" will be used to describe movement and relative positions. Figure 1A-Figure 1DAs can be seen, the term "distal" refers to the relative position and / or movement in the direction of the end 136 of the introducer sheath 130 (i.e., in the direction of the patient), and "proximal" refers to the relative position and / or movement in the direction of the device locking assembly 192 (i.e., in the direction of the user).

[0054] In the descriptions therein, the term "about" should be interpreted as + / - 10%.

[0055] A steerable introducer sheath assembly embodying the present disclosure includes an introducer sheath portion extending distally from a handle portion that can be grasped and manipulated by a user. One or more steering cables are attached to the distal end of the introducer sheath, proximally passing through a longitudinal steering cable within the introducer sheath to the interior of the handle portion, wherein the proximal ends of the steering cables are engaged by at least one mechanism that allows a user to manipulate the distal end of the introducer sheath by selectively increasing or decreasing the tension of the steering cables. The precise location at which the distal ends of the steering cables are attached at or near the distal tip of the introducer sheath can be varied proximally or distally as desired to provide a desired amount of distal curvature modification when the tension of the steering cables is increased or decreased. The introducer sheath portion also includes a longitudinal device lumen that is capable of slidably receiving a catheter-inserted instrument, which instrument can include a dilator (e.g., such as a Figure 8C and 8D The dilator is passed through a standard length BaylissRF transseptal device (available from Bayliss Medical, Montreal, Canada), a Brockenbrough transseptal needle, or other similar device. The handle portion also includes features that allow the user to finely control the advancement of the catheter insertion device through the introducer sheath.

[0056] Figure 1A and Figure 3A Exemplary features of a steerable introducer sheath assembly according to an embodiment of the present disclosure are shown. Figure 1A As best shown in FIG. 1 , the steerable introducer sheath assembly may include a handle portion 110 and an introducer sheath 130 extending outwardly from a distal end ( 116 ) of the handle portion 110 . Figure 3A As best shown in FIG. 1 (depicting a planar cross-section of the introducer sheath 130 perpendicular to the longitudinal center axis 102), the introducer sheath 130 may include a more or less centrally located device lumen 140 configured to slidably receive a catheter-inserted instrument (e.g., Fig. 8A and Figure 8C159), a first steering cable lumen 146 and a second steering cable lumen 148 in which a first steering cable 154 and a second steering cable 156 (respectively) are slidably disposed, and a third steering cable lumen 150 in which a third steering cable 158 is slidably disposed.

[0057] Reference again Figure 3A , the first steering cable lumen 146 and the second steering cable lumen 148 can be disposed on opposite sides of the device lumen 140 along a horizontal plane formed by the horizontal axis 104 and the longitudinal center axis 102, and symmetrically about a vertical plane formed by the vertical axis 103 and the longitudinal center axis 102, wherein the horizontal plane and the vertical plane are perpendicular to each other. In this way, adjusting the tension in the first steering cable 154 and the second steering cable 156 adjusts the "horizontal" curvature of the distal portion 132 of the introducer sheath to the left or right side of the vertical plane while minimizing potential unintended movement within the vertical plane. Figure 3A As further depicted in FIG. 1 , the third steering cable lumen 150 and the device lumen are arranged along a vertical plane, with the third steering cable lumen 150 arranged above the device lumen 140 (ie, closer to the device lumen 140). Figure 1C The "top" view shown is for viewing a user of the steerable introducer sheath. Thus, adjusting the tension on the third steering cable 158 will adjust the "vertical" curvature of the distal portion 132 of the introducer sheath 130 within the vertical plane while minimizing any undesirable deflection of the introducer sheath 130 to the left or right of the vertical plane. In other words, when an operator is viewing the sheath assembly 100 from the proximal handle portion 110 and looking distally along the introducer sheath 130 as the introducer sheath 130 extends outwardly in an undeflected position, the first steering cable 154 and the second steering cable 156 can be used to achieve a "horizontal" curvature of the distal portion 132 of the introducer sheath 130 to the left and right of the axis 102, respectively. Figure 1C ), and the third steering cable 158 can be used to adjust the amount of "vertical" curvature of the distal portion 132 of the introducer sheath 130, thereby lifting the distal portion 132 "upward" (i.e., toward the user) from the axis 102 (e.g., Figure 1D ).

[0058] Other embodiments of the steerable introducer sheath assembly of the present disclosure may include Figure 3B The depicted introducer sheath (depicting a planar cross-section of the introducer sheath 1300 perpendicular to the longitudinal center axis 102) includes a more or less central device lumen 1400 configured to slidably receive a catheter-inserted instrument (e.g., Fig. 8A and Figure 8C159), first steering cable lumen 1460 and second steering cable lumen 1480 (in which first steering cable 1540 and second steering cable 1560 are slidably disposed (respectively), and third steering cable lumen 1500 and fourth steering cable lumen 1420 (in which third steering cable 1580 and fourth steering cable 1520 are slidably disposed (respectively). Figure 3B As further depicted in FIG. 1 , first steering cable lumen 1460 and second steering cable lumen 1480 are disposed on opposite sides of device lumen 1400 along a horizontal plane formed by horizontal axis 104 and longitudinal center axis 102, and are symmetrical about a vertical plane formed by vertical axis 103 and longitudinal center axis 102, wherein the horizontal plane and the vertical plane are perpendicular to each other. Third steering cable lumen 1500 and fourth steering cable lumen 1420 are disposed on opposite sides of device lumen 140 along a vertical plane formed by vertical axis 103 and longitudinal center axis 102, and are symmetrical about a horizontal plane formed by horizontal axis 104 and longitudinal center axis 102.

[0059] For those with Figure 3B In the introducer sheath of the cable arrangement shown, adjusting the tension in the first steering cable 1540 and the second steering cable 1560 modifies the "horizontal" curvature of the distal portion of the introducer sheath in the direction of the horizontal axis 104 (i.e., to the left or right of the vertical plane). Figure 6C , which depicts an introducer sheath 1300 having a "horizontal" curvature to the left of the vertical plane ( Figure 6C , left), introducer sheath 1300 without "horizontal" curvature ( Figure 6C , middle) and an introducer sheath 1300 ( Figure 6C , right side). Similarly, adjusting the tension in the third steering cable 1580 and the fourth steering cable 1520 modifies the "vertical" curvature of the distal portion of the introducer sheath in the direction of the vertical axis 103 (i.e., curving above or below the horizontal plane). Fig.6D , which depicts an introducer sheath 1300 having a "vertical" curvature below the horizontal plane ( Fig.6D , left), introducer sheath 1300 without "vertical" curvature ( Fig.6D , middle) and an introducer sheath 1300 having a "vertical" curvature above the horizontal plane ( Fig.6D , right side).

[0060] The handle portion of the steerable introducer sheath assembly according to an embodiment of the present disclosure includes features that allow a user to selectively increase or decrease steering cable tension in order to achieve a desired "horizontal" or "vertical" curvature to the distal portion of the introducer sheath. Figure 1B-Figure 1D As best shown in FIG. 1 , for example, the handle portion 110 may include a steering rod 160 for adjusting the tension in the first steering cable and the second steering cable to modify the “horizontal” curvature (eg, Figure 1C 130 and further discussed below), and a distal cap 180 for adjusting the tension in the third steering cable in order to modify the "vertical" curvature of the distal portion 132 of the introducer sheath 130 (e.g. Figure 1D and discussed further below).

[0061] In some embodiments, the mechanism for manipulating the first and second steering cables 154, 156 to adjust the amount of "horizontal" curvature of the distal portion 132 of the introducer sheath may include an external steering rod 160 that controls an internal system of drive gears and a rotating column coupled to the steering cables 154 and 156. For example, Figure 2A , Figure 5A and Figure 5B As best shown in FIG. 1 , the steering rod 160 may be pivotally secured to a first end of a steering column 164 via a hole aligned to receive a steering rod pin 198. The steering column 164 is non-rotatably secured at its second end to a drive gear 166. The drive gear 166 is located within the handle 100 so that both the first gear assembly 168 and the second gear assembly 174 can be engaged and rotated simultaneously. Figure 2A As best shown in FIG. 1 , first gear assembly 168 and second gear assembly 174 may each include a rotatable post (126, 128) extending inwardly from a housing on the interior of handle 100, a non-rotatably fixed barrel portion (172, 178), and a non-rotatably fixed gear (170, 176) engaged with drive gear 166. Posts 126 and 128 may be positioned perpendicular to central axis 102 (e.g., as shown in FIG. 1 ). Figure 2A , 5A 5B) or alternatively at a non-perpendicular angle to the central axis 102. The posts 126 and 128 may be rotationally engaged by retaining features extending inwardly from the inner surface of the upper housing portion 112, the lower housing portion 114, or both. For example, as Figure 5C Best shown in FIG (depicting the base flange and showing the engagement of the column 126 with the base flange 1914 in the lower shell portion 114), in some embodiments, the columns 126 and 128 can be rotationally engaged via circular base flanges 1914 in the upper shell portion 112 and the lower shell portion 114.

[0062] As briefly noted above and in Figure 1A and Figure 2AAs best shown in the drawings, the distal ends of the first steering cable 154 and the second steering cable 156 are attached at or near the distal tip 136 of the introducer sheath, wherein the cables themselves extend proximally through the steering lumens 146 and 148 (respectively) until the proximal ends terminate within the interior of the handle portion 110, wherein the proximal ends of the two cables can be engaged by one or more steering mechanisms that are capable of selectively increasing or decreasing the tension in the steering cables.

[0063] For example, Figure 2A As best shown in FIG. 1 , first steering cable 154 and second steering cable 156 can exit introducer sheath 130 through respective openings 1960 and 1961 located near a distal portion (i.e., a portion located within handle portion 110) of introducer sheath 130. In this manner, the proximal ends of first steering cable 154 and second steering cable 156 can pass through steering lumens 146 and 148 (respectively) and engage first steering gear assembly 168 and second steering gear assembly 174 (respectively). Figure 3B In an embodiment of a steerable introducer sheath assembly of the present disclosure that is similar to the introducer sheath 1300 shown in FIG. 1 , the proximal ends of the first steering cable 1540 and the second steering cable 1560 (respectively) are connected to the Figure 2A Openings similar to those shown (1960 and 1961) pass through the first steering cable lumen 1460 and the second steering cable lumen 1480 and engage the first steering gear assembly 168 and the second steering gear assembly 174 (respectively).

[0064] like Figure 2A 17 and 18. For example, as best shown in FIG. 1 , in some embodiments, a proximal end of first steering cable 154 is attached to barrel portion 172 of first gear assembly 168, and a proximal end of second steering cable 156 is attached to barrel portion 178 of second gear assembly 174. Drive gear 166 engages first gear 170 and second gear 176 such that rotation of drive gear 166 causes first gear assembly 168 and second gear assembly 174 to rotate simultaneously, thereby adjusting the tension applied to first steering cable 154 and second steering cable 156, which are attached to and wound around barrel portion 172 and barrel portion 178, respectively, such that when tension in one of the steering cables increases due to rotation of steering bar 160, tension in the other steering cable decreases. In this manner, the first steering cable 154 and the second steering cable 156 work in unison to increase or decrease the “horizontal” curvature of the distal portion 132 to the left or right of the axis 102 .

[0065] In certain embodiments, the first steering cable 154 and the second steering cable 156 are attached to and engaged by the barrel portions 172 and 178, respectively, in such a manner that: Figure 1C 102, turning the steering rod 160 in a counterclockwise manner (i.e., such that the distal end of the steering rod 160 points more "left" relative to the longitudinal center axis 102) causes the distal portion (136) of the introducer sheath 130 to bend more "horizontally" to the left of the longitudinal center axis 102 ( Figure 1C , on the left side), turning the steering rod 160 in a clockwise direction (i.e., such that the distal end of the steering rod 160 points more to the "right" relative to the longitudinal center axis 102) causes the distal portion (136) of the introducer sheath 130 to bend more "horizontally" to the right side of the longitudinal center axis 102 ( Figure 1C , on the right side), and returning the steering rod 160 to the center position (i.e., pointing the distal end of the steering rod 160 in a direction parallel to the longitudinal center axis 102) causes the distal portion (136) of the introducer sheath 130 to extend in a direction parallel to the longitudinal center axis 102 (i.e., without a "horizontal" curvature, as Figure 1C In this manner, the orientation of the distal end of steering rod 160 can provide an indication to the user of the presence, directionality, and relative degree of any “horizontal” curvature that has been introduced to the distal portion ( 136 ) of introducer sheath 130 .

[0066] In an alternative embodiment, the first steering cable 154 and the second steering cable 156 can be attached to and engaged by the barrel portions 172 and 178 such that turning the steering rods in a "counterclockwise" manner will cause the distal portion (136) of the introducer sheath 130 to be bent "horizontally" to the right, and vice versa.

[0067] In certain embodiments of the steerable introducer sheath assembly according to the present disclosure, the interaction between the steering rod 160, the drive gear 166, and / or the first gear assembly 168 and the second gear assembly 174 can be modified to increase or decrease the "sensitivity" of the steering rod 160 (i.e., the degree to which "horizontal" curvature is introduced when the steering rod 160 is rotated to a certain degree). For example, in certain embodiments, a variable transmission can be provided that allows a user to adjust the "sensitivity" of the steering rod 160 by selectively modifying the transmission ratio between the drive gear 166 and / or the first gear assembly 168 and the second gear assembly 174. Alternatively, a spring-loaded gear column and / or a flywheel assembly can be provided for adjusting the sensitivity of the steering rod 160 in a desired manner.

[0068] In certain embodiments, the steerable introducer sheath assembly may include a mechanism for locking the steering rod in position once the desired amount of curvature has been achieved for the introducer sheath. Figure 5A and Figure 5B As shown, for example, the steering rod 160 may include a cam surface 162 so that when the steering rod 160 is moved from an "unlocked" position ( Figure 5A ) Rotate upward to the "locked" position ( Figure 5B ), the cam surface 162 frictionally engages with the outer surface of the upper handle portion 112, and the steering column 164 is lifted away from the handle interior in a radial direction, so that the drive gear 166 frictionally engages with the inner surface of the upper handle portion 112. In some embodiments, this "locking" friction can be adjusted by providing one or more washers to separate the drive gear 166 and the inner surface of the upper handle portion 112, which washers can include, for example Figure 5A and Figure 5B Wave spring washer 1915 is depicted.

[0069] like Figure 5A , Figure 5B and Figure 5D As shown, some embodiments may include a dome cap 1916 that seats within a dome cap recess 1917 that extends from the outer surface of the upper handle portion 112 to adjust the interaction between the cam surface 162 of the steering rod and the outer surface of the upper handle portion 112. Figure 5D (Inset) As best shown, the dome cover 1916 can be shaped to provide a central slot 1917 from which the steering rod 160 extends, wherein the slot 1917 is of sufficient width to accommodate vertical rotation between the "unlocked" and "locked" positions, while also providing lateral support for the steering rod 160 when the steering rod 160 is manipulated to rotate the steering column 164, and also ensuring that the steering rod 160 is rotated when it is moved from the "unlocked" position ( Figure 5A ) pivots to the "locked" position ( Figure 5B ), the steering rod 160 is restricted in a direction perpendicular to the axis of the steering rod pin 198.

[0070] In certain embodiments, dome cap 1916 and dome cap recess 1917 may be configured to limit angular displacement of steering column 164 about its longitudinal axis when steering rod 160 is manipulated. Figure 5D As shown, for example, this may be accomplished by flanges (1918 and 1919) extending from the underside of dome cover 1916 and interacting with distal surfaces formed by corresponding protrusions 1920 and 1921 (respectively) to limit rotation of steering rod 160. This protects cables 154 and 156 from excessive strain that may result from a user attempting to overtighten the cables using steering rod 160. In some embodiments, protrusions 1920 and 1921 and / or flanges 1918 and 1919 may be adjustable so that the degree to which rotation of steering rod 160 is restricted may be modified based on user preference.

[0071] The embodiment of the steerable introducer sheath assembly disclosed herein is characterized by having Figure 3B The introducer sheath of the cable arrangement shown, the steering rod with the steering assembly mechanism and other associated features described above can be similarly used to adjust the tension in the first steering cable 1540 and the second steering cable 1560 to modify the "horizontal" curvature of the distal portion of the introducer sheath in the direction of the horizontal axis 104 (i.e., to the left or right of the vertical plane). For such embodiments, the first steering cable 1540 and the second steering cable 1560 are arranged in the same manner as described above for the first steering cable 154 and the second steering cable 156 from the introducer sheath 130 (and in Figure 2A 172 and 178 in the same manner as shown in FIG. Figure 1C and Figure 6C Turning the steering rod 160 in a counterclockwise manner (i.e., such that the distal end of the steering rod 160 points more to the "left" relative to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to curve more "horizontally" to the left (ie, to the left) of the longitudinal center axis 102 when viewed from the "top" as shown. Figure 6C ), rotating the steering rod 160 in a clockwise direction (i.e., such that the distal end of the steering rod 160 points more to the "right" relative to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to bend more "horizontally" to the right of the longitudinal center axis 102 ( Figure 6C , on the right side), and returning the steering rod 160 to the center position (i.e., such that the distal end of the steering rod 160 points in a direction parallel to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to extend in a direction parallel to the longitudinal center axis 102 (i.e., without a "horizontal" curvature, as Figure 6C Here again, the orientation of the distal end of the steering rod 160 indicates the presence, directionality, and relative extent of any "horizontal" curvature that has been introduced into the distal portion (1360) of the introducer sheath 1300.

[0072] This is Figure 6C , which depicts an introducer sheath 1300 having a "horizontal" curvature to the left of the vertical plane ( Figure 6C , left), introducer sheath 1300 without "horizontal" curvature ( Figure 6C , middle) and an introducer sheath 1300 ( Figure 6C , right side). Similarly, adjusting the tension in the third steering cable 1580 and the fourth steering cable 1520 modifies the "vertical" curvature (i.e., bending above or below the horizontal plane) of the distal portion of the introducer sheath in the direction of the vertical axis 103. Fig.6D , which depicts an introducer sheath 1300 having a "vertical" curvature below the horizontal plane ( Fig.6D , left), introducer sheath 1300 without "vertical" curvature ( Fig.6D , middle) and a deflector jacket 1300 having a "vertical" curvature above the horizontal plane ( Fig.6D , right side).

[0073] As previously mentioned, the handle portion of the steerable introducer sheath according to embodiments of the present disclosure may also include features that allow a user to selectively increase or decrease the steering cable tension in order to achieve a desired "vertical" curvature to the distal portion of the introducer sheath. For example, the handle portion 110 may include a distal cap 180 that controls the axial movement of the externally threaded rod 188 to adjust the tension in the third steering cable in order to modify the "vertical" curvature of the distal portion 132, such as Figure 1D shown (on the left and in the center).

[0074] from Figure 1A-Figure 1D As can be seen in the figure, the handle portion 110 can include an upper housing portion 112 and a lower housing portion 114, which together define a distal aperture 118 disposed at a distal end (116) of the handle portion 110. In some embodiments, the distal aperture 118 can be configured to rotatably receive a distal cap 180 such that the distal cap 180 is free to rotate relative to the handle portion 110. For example, Figure 2A and 2B As shown in FIGS. 7B and 7B , the distal cap 180 may include a plurality of ridges 182 extending radially outward from the outer surface so that the distal cap 180 may be easily grasped and rotated during use. The distal cap 180 may also include an internally threaded portion 186 that engages with a correspondingly threaded rod 188 disposed within the handle portion 110. The distal cap 180 may also include an outwardly overhanging radial flange disposed at its proximal end, having a diameter greater than the diameter of the distal orifice 118, thereby allowing the distal cap 180 to be received and axially retained within the annular cavity 120 defined by the combination of the upper housing portion 112 and the lower housing portion 114 to form the handle portion 110.

[0075] like Figure 2A-2B and Figure 7B As best shown in FIG. 1 , in certain embodiments, the outwardly overhanging radial flange disposed at the proximal end of the distal cap 180 may be comprised of a plurality of tabs 184 having outwardly overhanging members that together define a discontinuous radial flange having a radius greater than the radius of the distal orifice 118 such that the distal cap 180 may be received and axially retained within the annular cavity 120. Figure 2BAs best shown in FIG. 1 , distal cap 180 may also include a plurality of vent holes 1850 that correspond to tabs 184 in an arrangement that facilitates manufacturing distal cap 180 using injection molding techniques.

[0076] like Figure 4A and Figure 4B As can be seen in the figure, the externally threaded rod 188 may include one or more axially extending slots 189, which may engage one or more axially extending flanges 129 that protrude radially inward from the inner surface of the handle 110. When the distal cap 180 is rotated, the engagement of the (multiple) slots 189 and the (multiple) flanges 129 ensures that the externally threaded rod 188 will not rotate either. As a result, when the user rotates the distal cap 180, the externally threaded rod 188 moves axially in the proximal or distal direction (i.e., parallel to the longitudinal center axis 102). As discussed in more detail below, the axial movement of the externally threaded rod 188 generated by the rotation of the distal cap 180 is used to introduce a "vertical" curvature to the distal portion 132 of the introducer sheath 130.

[0077] To ensure that forces are properly transferred to the distal portion 132 of the introducer sheath 130 during operation (e.g., when a user increases or decreases tension in one or more of the steering cables to introduce "horizontal" and / or "vertical" curvature to the proximal end of the introducer sheath 130), the steerable introducer sheath according to embodiments of the present disclosure may also include a torque transfer lock that prevents the introducer sheath 130 from rotating about the longitudinal center axis 102. Figure 4A and 4B As best shown in FIG. 1 , some embodiments may include a torque transfer lock 1900 that includes a hollow post having an outer diameter that allows it to pass through the inner bore of the externally threaded rod 188, an inner diameter sufficient to encompass the radial diameter of the introducer sheath 130, and a notch 1901 at its proximal end that is capable of engaging with the flange 129. The distal end 900 of the torque transfer lock 1900 includes external threads 1902 that correspond to the threads on the inner bore of the transfer lock cover 1903. When screwed onto the transmission lock 1900, the proximal surface of the transfer lock cover 1903 is capable of movably engaging with the distal surface of the distal end cover 180 to secure the transfer lock 1900 within the bore of the externally threaded rod 188, wherein the notch 1901 is fully engaged with the flange 129. In certain embodiments, the movable engagement between the transfer lock cover 1903 and the distal cover 180 may be facilitated by the use of a thrust bearing 1905, which may be seated within a notch 1904 on the distal face of the distal cover 180. In the final assembly, the introducer sheath 130 passes through the aperture of the torque transfer lock 1900 and is immovably attached thereto, and thus the engagement of the notch 1901 with the flange 129 prevents the introducer sheath 130 from rotating about the longitudinal center axis 102 when a "vertical" curvature is introduced using the distal cover 180, or when a "horizontal" curvature is introduced using the steering rod 160.

[0078] The proximal terminus of the third steering cable 158 can be attached to an externally threaded rod 188 such that the tension of the third steering cable 158 can be increased or decreased by rotating the distal end cap 180, which causes the externally threaded rod 188 to move distally or proximally along the axis 102. Figure 1A and Figure 2D As best shown in FIG. 1 , for example, the distal end of the third steering cable 158 is attached at or near the distal end 136 of the introducer sheath 130 and extends proximally therefrom through the steering lumen 150 until the proximal end terminates within the interior of the handle portion 110, whereupon the third steering cable 158 exits the introducer sheath 130 via an opening 1963 located near the distal portion of the introducer sheath 130 (i.e., the portion located within the interior of the handle portion 110). In this manner, the distal end of the third steering cable 158 is able to pass from the steering lumen 150 and attach to the externally threaded rod 188 by passing the third steering cable 158 through the axial hole 1963 in the flange 400 extending from the proximal end of the externally threaded rod 188 and attaching the third steering cable 158 after the third steering cable 158 exits the distal end of the axial hole 1963. Similarly, for embodiments of the steerable introducer sheath assembly of the present disclosure, it includes a Figure 3B The distal end of the third steering cable 1580 passes through the steering cable lumen 1500 and is connected to the guide sheath 1300 of the present invention. Figure 2D 1963 and discussed above. Once it is passed out of the introducer sheath 1300, the third steering cable 1580 can be attached to the externally threaded rod 188 by passing it through the axial hole 1963 in the flange 400, which extends from the proximal end of the externally threaded rod 188, and attaching the third steering cable 1580 after it exits the distal end of the axial hole 1963.

[0079] like Figure 2A and Figure 2D As best shown in FIG. 1 , when an operator is viewing the sheath assembly 100 from the proximal handle portion 110 and looking distally along the introducer sheath 130 when it is extended outwardly in the undeflected position, rotation of the distal end cap 180 in a clockwise direction causes the corresponding threaded rod 188 to move in a proximal direction (i.e., toward the interior of the handle portion 110, as shown in FIG. 1 ). Figure 2D , top), which increases the tension applied to the third steering cable 158 and thereby causes a "vertical" curvature of the distal portion 132 of the introducer sheath 130. Conversely, rotation of the distal cap 180 in a counterclockwise direction causes the externally threaded rod 188 to be rotated distally (i.e., away from the interior of the handle portion 110, as shown in FIG. Figure 2D, bottom), which reduces the amount of tension present in the third steering cable 158 and reduces the amount of "vertical" curvature present in the distal portion 132 of the introducer sheath 130. Figure 1D 102, which shows how, when the distal cap 180 is rotated, the distal portion (136) of the introducer sheath 130 extends in a direction parallel to the longitudinal center axis 102 so that the externally threaded rod 188 does not exert tension on the steering cable 158 ( Figure 1D , in the center), and how the distal portion (136) of the introducer sheath 130 bends more "vertically" in a direction elevated relative to the longitudinal center axis 102 when the distal cap 180 is rotated to move the externally threaded rod 188 in a proximal manner and increase the tension on the steering cable 158 ( Figure 1D , on the left). A "self-locking" feature that retains the desired "vertical" curvature can be provided by configuring the threaded portion of the distal cap 180 and the externally threaded rod 188 to interact with each other with sufficient friction so that when the user stops rotation of the distal cap 180, the externally threaded rod 188 remains fixed in its position, thereby maintaining tension in the third steering cable 158 and maintaining the desired "vertical" curvature to the distal portion 132 of the introducer sheath 130.

[0080] In certain embodiments of the introducer sheath assembly of the present disclosure, the engagement between the end cap 180 and the externally threaded rod 188 can be used to adjust a Figure 3B The "vertical" curvature of the introducer sheath 1300 depicted. In these embodiments, proximal / distal movement of the externally threaded rod 188 is utilized (directly or indirectly) to selectively increase or decrease the relative tension in the third steering cable 1580 and the fourth steering cable 1520, thereby modifying the "vertical" curvature (i.e., above or below the horizontal plane) of the distal portion 1360 of the introducer sheath 1300 in the direction of the vertical axis 103. Figure 1D 150 (depicting a steerable introducer sheath viewed from the "right hand" side), which illustrates how, when the distal cap 180 is rotated, the distal portion (136) of the introducer sheath 130 extends in a direction parallel to the longitudinal center axis 102 so that the externally threaded rod 188 does not exert tension on the third steering cable 1580 and the fourth steering cable 1520 ( Figure 1D, in the center), and how the distal portion (136) of the introducer sheath 130 bends more "vertically" in a direction elevated relative to the longitudinal center axis 102 ( FIG. 14A , FIG. 14B ) as the distal cap 180 is rotated to move the externally threaded rod 188 in a manner that increases the tension on the third steering cable 1580 and decreases the tension on the fourth steering cable 1520 ( FIG. 14A , FIG. 14B ). Figure 1D , on the left), and how the distal portion (136) of the introducer sheath 130 bends more "vertically" in a downward direction relative to the longitudinal center axis 102 when the distal cap 180 is rotated to move the externally threaded rod 188 in a manner that reduces the tension on the third steering cable 1580 and increases the tension on the fourth steering cable 1520 ( Figure 1D ,on the right).

[0081] Certain embodiments of the steerable introducer sheath assembly may include a "horizontal" steering rod for adjusting the amount of "horizontal" curvature present in the distal portion of the introducer sheath (as described above with respect to the Figure 1A-Figure 1D and Figure 2A ), and a "vertical" steering rod for adjusting the amount of "vertical" curvature present in the distal portion 132 of the introducer sheath 130. In such "dual rod" embodiments, the use of a "vertical" steering rod in place of the distal cap and externally threaded rod assembly described above for controlling the "vertical" curvature provides consistency relative to the mechanism used to vary the introducer sheath curvature (i.e., the same type of mechanism - the steering rod - is used to modify both the "vertical" and "horizontal" curvatures).

[0082] For example, Figure 6A-6D As shown, from Figure 1A-Figure 1C and Figure 4A-4B The distal cap 180 and its associated components (externally threaded rod 188, torque transfer lock 1900, transfer lock cap 1903, and thrust bearing washer 1905) of the depicted steerable introducer sheath assembly may be replaced with a distal housing assembly 350, such as Figure 6B As best shown in FIG. 3 , distal housing assembly 350 includes distal housing portions 361 and 362 that together house a vertical steering assembly 351 that is articulated by a vertical steering rod 360. Figure 6BAs best shown in FIG. 1 , the vertical steering rod 360 is non-rotatably fixed to a first end of a steering column 364 by a hole aligned to receive a retaining pin. The steering column 364 in turn passes through the distal housing portion 361 and is non-rotatably fixed at its second end to a main vertical drive gear 365. The main vertical drive gear 365 is located within the distal housing assembly 350 so as to be able to engage and rotate both the upper vertical drive gear 366 and the lower vertical drive gear 369 simultaneously. The upper vertical drive gear 366 is non-rotatably fixed to an upper rotatable post 367, which extends inwardly from housings 374 and 375 on the interior of the distal housing portions 361 and 362 (respectively), wherein the upper rotatable post 367 is also non-rotatably fixed to the upper barrel portion 368. The lower vertical drive gear 369 is non-rotatably secured to a lower rotatable post 370 that extends inwardly from housings 376 and 377 on the interior of distal housing portions 361 and 362 (respectively), wherein the lower rotatable post 370 is also non-rotatably secured to the lower barrel portion 371 .

[0083] In certain embodiments of the steerable introducer sheath assembly of the present disclosure, a combination similar to Figure 3B The vertical steering rod and associated components described above are provided by the introducer sheath of the introducer sheath 1300 shown. In these embodiments, the third steering cable 1580 and the fourth steering cable 1520 are attached at or near the distal tip 1360 of the introducer sheath 1300, wherein the cables themselves extend proximally through the inner lumens 1500 and 1420, respectively, until the proximal ends terminate within the handle portion 110, whereupon the proximal ends of the third steering cable 1580 and the fourth steering cable 1520 (respectively) pass through the steering cable lumens 1500 and 1420 and are connected to the handle portion 110. Figure 2A Openings similar to those depicted in ( 1960 and 1961 ) exit the introducer sheath 1300 and engage one or more steering mechanisms that are capable of selectively increasing or decreasing the tension in the third steering cable 1580 and the fourth steering cable 1520 .

[0084] In these embodiments, the proximal end of third steering cable 1580 is attached to upper barrel portion 368, and the proximal end of fourth steering cable 1520 is attached to lower barrel portion 371. Rotation of vertical steering rod 360 moves main vertical drive gear 365 to simultaneously engage and rotate with upper and lower vertical drive gears 366, 369 and their associated upper and lower barrel portions 368 and 371. This, in turn, causes third and fourth steering cables 1580, 1520 to wrap around lower barrel portions 368 and 371, respectively, such that as tension in third steering cable 1580 increases, tension in fourth steering cable 1520 decreases, and vice versa. In this manner, the third steering cable 1580 and the fourth steering cable 1520 work in unison to increase or decrease the "vertical" curvature of the distal portion 1320 of the introducer sheath 1300 in a direction that is raised above or lowered below the horizontal plane.

[0085] For example, in some embodiments, the first steering cable 1580 and the second steering cable 1520 can be attached and joined by their respective upper barrel portions 368 and lower barrel portions 371, such as Fig.6D 102 (providing a view of a "two rod" steerable introducer sheath viewed from the "right hand" side), such that the steering rod 360 is rotated in a counter-clockwise direction (i.e., such that the distal end of the steering rod 360 points in an elevated direction relative to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to bend "vertically" in an elevated manner relative to the longitudinal center axis 102 ( Fig.6D , on the left side), rotating the steering rod 360 in a clockwise manner (i.e., such that the distal end of the steering rod 360 points in a direction lowered relative to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to bend "vertically" in a lowered manner relative to the longitudinal center axis 102 ( Fig.6D , at the bottom), and returning the steering rod 160 to the center position (i.e., such that the distal end of the steering rod 360 points in a direction parallel to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to extend in a direction parallel to the longitudinal center axis 102 (i.e., without a "horizontal" curvature, as Fig.6D In this manner, the orientation of the distal end of steering rod 360 can provide an indication to the user of the presence, directionality, and relative degree of any "horizontal" curvature that has been introduced to the distal portion (1360) of introducer sheath 1300.

[0086] In an alternative embodiment, the third steering cable 1580 and the fourth steering cable 1520 can be attached to and engaged by the barrel portions 368 and 371, respectively, such that rotating the vertical steering rod 360 in a "clockwise" manner will cause the distal portion (1360) of the guide sheath 1300 to bend "vertically" above the longitudinal center axis 102, and vice versa.

[0087] In certain embodiments of the introducer sheath assembly of the present disclosure, it can be used with a similar Figure 3A The introducer sheath of the depicted introducer sheath 130 provides a vertical steering rod and certain associated elements similar to those described above. For example, the vertical steering rod can be fixed to the first end of a rotatable column that extends through the surface of the distal handle assembly 350 and is similar to Figure 6B 360 and rotatable post 364. The distal end of the third steering cable 158 from the introducer sheath 130 is attached (directly or indirectly) to and engaged by the rotatable post 364, so that when the steering rod 360 is rotated as described above, the resulting axial rotation of the rotatable post 364 causes the proximal end of the third steering cable 158 to be coiled or unwound from around the barrel portion of the rotatable post 364. As the third steering cable 158 is coiled more around the barrel portion of the rotatable post 364, the tension 158 applied to the third steering cable 158 increases, and the amount of "vertical" curvature present in the distal portion 132 of the introducer sheath likewise increases. Conversely, as the third steering cable 158 is coiled less around the barrel portion of the rotatable post 364, the tension applied to the third steering cable 158 decreases, and the amount of curvature present in the distal portion 132 of the introducer sheath 130 likewise decreases. For example, in some embodiments, the third steering cable 158 may be attached to and engaged by the rotatable post 364 in such a manner that: Fig.6D As best shown in FIG. 1 (which provides a view of a "two-rod" steerable introducer sheath viewed from the "right hand" side), rotation of the steering rod 360 in a counter-clockwise manner (i.e., such that the distal end of the steering rod 360 is elevated relative to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to bend "vertically" above the longitudinal center axis 102 ( Fig.6D , on the left side), and returning the steering rod 160 to the center position (i.e., such that the distal end of the steering rod 360 points in a direction parallel to the longitudinal center axis 102) causes the distal portion (1360) of the introducer sheath 1300 to return to extending in a direction parallel to the longitudinal center axis 102 (i.e., without a "vertical" curvature, as Fig.6D Here again, the orientation of the distal end of the steering rod 360 provides an indication of the presence, directionality, and relative extent of any "vertical" curvature that has been introduced to the distal portion (1360) of the introducer sheath 1300.

[0088] In certain embodiments of the steerable introducer sheath assembly according to the present disclosure, the interaction between the vertical steering rod and the associated steering gear assemblies (such as those described above for the vertical steering rod 360) can be modified to increase or decrease the "vertical sensitivity" of the vertical steering rod (i.e., the degree to which the "vertical" curvature is modified when the vertical steering rod is rotated to a certain degree). For example, in certain embodiments, a variable transmission can be provided that allows a user to adjust the "vertical sensitivity" by selectively modifying the gear ratio between the drive gear and any associated gear assemblies (e.g., allowing a user to modify the vertical sensitivity). Figure 6B Alternatively, a spring loaded gear column and / or flywheel assembly may be provided for adjusting the sensitivity of the vertical steering rod and associated steering assembly.

[0089] Embodiments of a steerable introducer sheath assembly that provides a vertical steering bar for controlling "vertical curvature" (as described above) may also include a mechanism for locking the vertical steering bar in position once the desired amount of curvature is achieved for the introducer sheath. Figure 6B As shown, for example, the distal handle assembly 350 can be configured with a vertical steering rod 360 including a cam surface 385, so that when the steering rod 360 is rotated upward about a steering rod pin that couples it to a steering column 364, the cam surface frictionally engages with the outer surface of the upper portion (361) of the distal handle assembly 350, and the steering column 364 (or associated elements) likewise frictionally engages with the inner surface of the upper portion (361) of the distal handle assembly 350. This "locking engagement" is similar to Figure 5A and 5B Basically the same as described in Figure 5A and 5B Depicted in the "unlocked" position ( Figure 5A ) and the "locked" position ( Figure 5B ) of the horizontal steering handle 160. In some embodiments, the horizontal steering handle 160 can be provided by providing one or more washers (e.g., Figure 5A and 5B The “locking” friction is adjusted by adjusting the wave spring washer (1915) depicted in FIG. 1 to adjust the frictional engagement with the inner and outer surfaces of the upper portion (361) of the distal handle assembly 350.

[0090] Reference again Figure 6B Embodiments of a steerable introducer sheath assembly providing a vertical steering rod for controlling the "vertical" curvature may also include a vertical steering rod dome cap 380 seated within a vertical dome cap recess 381 extending from the outer surface of the upper portion (361) of the distal handle assembly 350. The interaction between the cam surface 385 of the vertical steering rod 360 and the outer surface of the upper handle portion 361 is thereby adjusted. Figure 6B As best shown in FIG. 1 (left inset), the vertical steering rod dome cover 380 may be shaped to provide a central slot 386 from which the steering rod 360 extends, such as Fig. 6A and Fig.6D 386 has a width sufficient to accommodate vertical rotation of the vertical steering rod 360 between the "unlocked" and "locked" positions, while also providing lateral support for the steering rod 360 when manipulated to rotate the steering column 364, and also ensuring that the steering rod 360 is pivoted from the "unlocked" position to the "locked" position ( Figure 5B ), the steering rod 360 is constrained in a direction perpendicular to the axis of the steering rod pin that couples it to the steering column 364.

[0091] Reference again Figure 6B , providing an embodiment of a steerable guide sheath assembly for a vertical steering rod for controlling the "vertical" curvature, the vertical dome cover 380 and the vertical dome cover recess 381 can be configured to limit the angular displacement of the steering column 364 about its longitudinal axis when the vertical steering rod 360 is manipulated. For example, as Figure 6B This can be accomplished by flanges (381 and 382) extending from the underside of the vertical dome cover 380 and in conjunction with the flanges (381 and 382) formed by the Figure 6B (left inset) form distal surfaces of corresponding protrusions illustrated as 383 and 384 interact to limit the rotation of the steering rod 360. This protects the third steering cable 1580 and / or the fourth steering cable 1520 from excessive strain that may be caused by a user attempting to over-tighten them using the steering rod 360. In some embodiments, the protrusions 383 and 384 and / or the flanges 381 and 382 may be adjustable so that the degree to which the rotation of the steering rod 360 is limited can be modified according to the user's preference.

[0092] As described above, the first steering cable 154 and the second steering cable 156 work in unison to affect the curvature of the distal portion 132 of the introducer sheath 130, wherein the first gear assembly 168 and the second gear assembly 174 are simultaneously engaged by the drive gear 166 so that when the operator manipulates the steering rod 160 to increase the tension in the steering cable 154, the tension in the steering cable 156 is reduced by the same amount, and vice versa. When the user manipulates the steering rod 160 to achieve a "horizontal" bend of the distal portion 132 of the introducer sheath 130, the simultaneous operation of the gear assemblies 168 and 174 prevents slack from accumulating in the first steering cable 154 and the second steering cable 156. Figure 3BThe same is true of the guide sheath 1300 depicted in FIG, wherein the introduction of a "horizontal" curvature into the distal portion 1320 of the guide sheath 1300 by manipulating the steering rod 160 similarly does not result in slack accumulation in the first steering cable 1540 and the second steering cable 1560 because as the tension in one of the steering cables increases, the tension in the other steering cable decreases, and vice versa.

[0093] However, when the user increases the "vertical" curvature of the distal portion 132 of the introducer sheath 130 by increasing the tension of the third steering cable 158, this in turn may cause slack to accumulate in the first steering cable 154 and / or the second steering cable 156. Similarly, when the user modifies the "vertical" curvature of the distal portion 1320 of the introducer sheath 1300 by adjusting the tension of the third steering cable 1580 and the fourth steering cable 1520 (in a direction that is raised or lowered relative to the horizontal plane), this in turn may cause slack to accumulate in the first steering cable 1540 and / or the second steering cable 1560. This slack accumulation may cause an operator to experience an undesirably delayed response when attempting to modify the tension in the first steering cable 154 and the second steering cable 156 (or the first steering cable 1520 and / or the second steering cable 1580) using a horizontal steering rod (e.g., the steering rod 160 described above) in order to adjust the "horizontal" curvature of the distal portion 132 of the introducer sheath 130 (or the distal portion 1320 of the introducer sheath 1300). To prevent this, the steerable introducer sheath assembly of the present disclosure may include a mechanism for removing such slack.

[0094] For example, Fig. 7A and 7B As shown, the externally threaded rod 188 may be characterized by a proximally extending link flange 400, through which the axial movement of the externally threaded rod 188 is transmitted to a first slack removal assembly, which includes a first connecting arm 401, a second connecting arm 402, a flange link column 403 with an associated bearing cylinder 406, a connecting arm link column 404 with an associated bearing cylinder 407, and a connecting arm retaining column 405 with an associated bearing cylinder 408. More specifically, as Figure 7B 4, the linking flange 400 is coupled to the distal end of the first link arm 401 through an overlapping opening that receives the flange linking post 403; the proximal end of the first link arm 401 is coupled to the distal end of the second link arm 402 through an overlapping opening that receives the linking arm linking post 404; and the proximal end of the second link arm 402 includes an opening through which one end of the linking arm retaining post 405 passes and then seats in the linking arm retaining post receptacle 410 inside the lower housing portion 114. The first steering cable 154 passes through the slack removal assembly, as shown in FIG. Figure 7BAs shown in dashed lines in FIG. 1 , the bearing cylinders 406-408 are configured to act as rollers that rotate freely about their respective columns 403-405 to minimize friction with the steering cables 154. Figure 7B As further shown, the second link cable 156 passes through a second slack removal assembly that is also coupled to the link flange 400, wherein the second slack removal assembly includes a first link arm 411, a second link arm 412, a flange link column 413 with an associated bearing cylinder 416, a link arm link column 414 with an associated bearing cylinder 417, and a link arm retaining column 415 with an associated bearing cylinder 418, and these components are coupled together as described above with respect to the first slack removal assembly.

[0095] like Figure 7B As best shown in the figure, as the externally threaded rod 188 advances in the distal direction, the interaction between the link flange 400 and the slack removal assembly causes the columns 403-405 and 413-415 (and associated bearings 406-408 and 416-418) to align in a more linear manner, which in turn allows the steering cables 154 and 156 to travel along a shorter path from their distal attachment points within the introducer sheath 130 to their proximal attachment points at the gear assemblies 168 and 174. In contrast, as the externally threaded rod 188 is advanced in a more proximal direction, the interaction between the link flange 400 and the slack removal assembly causes the posts 403-405 and 413-415 (and associated bearings 406-408 and 416-418) to align in a more triangular configuration, with the link arm link posts 404 and 414 positioned significantly further toward the exterior of the handle portion 110 than the flange link posts 403 and 413 and link arm retaining posts 405 and 415. This triangular configuration removes excess slack from the steering cables 154 and 156 by causing them to travel a longer path from their distal attachment points within the introducer sheath 130 to their proximal attachment points at the gear assemblies 168 and 174. Thus, as the externally threaded rod 188 advances in a proximal direction increasing the tension on the third steering cable 158 (which in turn increases the "vertical" curvature, which may cause slack in the steering cables 154 and 156), the slack removal assembly described above is converted to a triangular configuration that removes excess slack by increasing the distance that the cables 154 and 156 travel from their proximal gear assemblies to the distal end of the introducer sheath 130.

[0096] Likewise, for those embodiments (i) and (ii) in which a "vertical" steering rod 360 is used, Figure 3B 1300, wherein the vertical steering rod 360 is rotated to adjust the "vertical" curvature of the distal portion 1320 of the introducer sheath 1300 (as discussed above and in Figure 6B and 6D ), or (ii) with Figure 3A , whereby the vertical steering rod 360 is rotated to adjust the "vertical" curvature of the distal portion 132 of the introducer sheath 130 (as discussed above and in Figure 6B and 6C ), the introduction of slack into the first steering cable 1520 and / or the second steering cable 1580 (from the introducer sheath 1300), or the first steering cable 154 and / or the second steering cable 156 (from the introducer sheath 130) may be addressed by coupling the rotation of the steering column 364 to the slack removal assembly. For example, one or more coupling rods or cables may be provided to couple the steering column 364 to the slack removal assembly such that when the user increases the tension in the third steering cable 158 by rotating the steering column 364 using the "vertical" steering rod 360 (thereby increasing the "vertical" curvature of the distal portion 132 of the inserter sheath 130), the coupling rods or cables cause the slack removal assembly to align in a "triangle" configuration, as discussed above and as shown in Figure 7B 14, which acts to remove excess slack from the steering cables 154 and 156 by causing them to travel a longer path from their attachment points at the distal tip of the introducer sheath 130 to their proximal attachment points at the gear assemblies 168 and 174. Conversely, when the user increases the tension in the third steering cable 158 by rotating the steering column 364 using the "vertical" steering rod 360 (thereby reducing or eliminating any "vertical" curvature of the distal portion 132 of the introducer sheath 130), the coupling rod or cable causes the slack removal assembly to align in a more linear manner, as discussed above and as shown in FIG. Figure 7B As shown, the steering cables 154 and 156 are allowed to travel along a shorter path from their distal attachment points within the introducer sheath 130 to their proximal attachment points at the gear assemblies 168 and 174.

[0097] The steerable introducer sheath assembly according to the present disclosure may also include a device locking assembly that allows the user to selectively secure the catheter insertion device within the introducer sheath after it has been advanced (or retracted) to the desired extent, and further exert fine control over the advancement or retraction of the catheter insertion device so attached. Such catheter insertion devices may include, for example, dilators through which a standard length Bayliss RF transseptal device (available from Bayliss Medical of Montreal, Canada), a Brockenbrough transseptal needle, or other similar device may be introduced. As in Figure 1A and 8A - Fig.8D As can be seen, for example, the device locking assembly can be disposed at the proximal opening 124 ( Figure 8B and Figure 8CThe proximal opening 124 is formed when the proximal sides of the upper shell portion 114 and the lower shell portion 114 are coupled together to form the handle portion 110. Figure 8A-8D As further shown, the device locking assembly may include a device locking bar (at Figure 8A-8C 191a in the Fig.8D 191b), which passes through the proximal surface of the handle portion 110, wherein the device locking rod includes a smooth central hole (199), through which the instrument for catheter insertion can be inserted into the steerable introducer sheath (130, 1300), and the device locking rod is also configured to be variably attached to the instrument for catheter insertion in an immovable manner. For example, from Figure 8B and Figure 8C As can be best seen in the depiction of the device locking rod 191a shown in FIG, in some embodiments, the device locking rod may have external threads at its proximal end to receive a hemostatic valve cover (196a) through which the catheter insertion instrument passes when it is inserted into the central hole 199 of the device locking rod, thereby allowing the user to selectively fix the catheter insertion instrument in the device locking rod 191a in an immovable manner by tightening or loosening the hemostatic valve cover 196a. Alternatively, as shown in FIG. Fig.8D As best seen in the depiction of the device locking rod 191b shown in FIG, in certain embodiments, the device locking rod may define a distal clamp 194 having a smooth outer surface, thereby allowing a user to selectively attach the catheter insertion device within the device locking rod 191b in a non-fixable manner by sliding a locking knob 196b, the sliding locking knob 196b defining a smooth frusto-conical hole 181 that engages with and compresses the clamp 194 inwardly so that it surrounds the catheter insertion device (in FIG. Fig.8D 159) is tensioned.

[0098] In certain embodiments, access to a catheter insertion instrument (e.g., a catheter insertion instrument) can be provided by configuring the device locking bars (191a, 191b) to be mechanically advanced (or retracted) through the proximal side of the handle portion 110 after the catheter insertion instrument has been immovably attached as described above. Fig. 8A and Fig.8D Further control of the advancement (or retraction) of the expander 159 shown. For example, as in Figure 8A-8C (device locking bar 191a shown) and Fig.8DAs best shown in FIG. 10A and FIG. 10B , the device locking rod 191b is shown, and the device locking rod may be configured with external threads 1923 that engage with corresponding threaded holes (197) through the advancement knob (195). The external threads on the device locking rods (191a, 191b) (including the external threads that engage with the threaded holes 197 and the external threads at the proximal end of the device locking rod 191a that engage with the hemostatic valve cover 196a) may be continuous (i.e., "all the way to the bottom") or, as shown in FIG. Fig. 8E (depicting device locking bar 191a), includes interrupted "flats" 1925 provided along the length of the externally threaded region to facilitate use of injection molding manufacturing techniques.

[0099] Reference again Figure 8A-8D The advancement knob may be rotatably received and retained within the proximal aperture 124 of the handle portion 110 by a retaining flange that extends radially from a distal portion of the advancement knob 195 and has a diameter greater than the proximal aperture 124. The radially extending retaining flange may be continuous or discontinuous. For example, Fig.8D An advancement knob 195 is shown with a continuous retaining flange (193b). Alternatively, Figure 2C 192 and 193. A close-up view, a side perspective view, and a distal view of advancement knob 195 are shown having a discontinuous retention flange including outwardly overhanging tabs 1926 that together define a flange having a radius greater than the radius of proximal aperture 124, thereby ensuring that advancement knob 195 is axially retained within handle portion 110 (e.g., Figure 2D and Fig. 9A best seen in ). Figure 2C As best seen in the figure, the advance knob (195) has a discontinuous retaining flange and may also include a plurality of ventilation holes 1927 through the proximal side of the advance knob 195, which correspond to the outwardly projecting tabs 1926 and are sized and positioned to facilitate the manufacture of the advance knob using injection molding techniques.

[0100] like Fig. 9A As best shown in FIG. 1 , rotation of advancement knob 195 causes device locking bars (191a, 191b) to move in a proximal direction (ie, toward the user, such as Fig. 9A , in the left direction) or in the distal direction (ie, away from the user and into the handle portion 110, as shown Fig. 9AIn some embodiments, the device locking bars (191a, 191b) and the advancement knob 195 may be threaded so that rotation of the advancement knob 195 in a counterclockwise manner causes the device locking bars (191a, 191b) to move in the proximal direction, and rotation of the advancement knob 195 in a clockwise manner causes the device locking bars (191a, 191b) to move in the distal direction; in other embodiments, the threads may be configured so that rotation of the advancement knob in a clockwise direction causes the device locking bars to move in the proximal direction, and rotation of the advancement knob in a counterclockwise direction causes the device locking bars to move in the proximal direction. Thus, in the engagement device locking assembly 192 ( Fig. 9A The device locking bar 191a shown is required to tighten the hemostatic valve cover 196a) to attach the instrument used for catheter insertion (e.g., Fig. 8A and Fig.8D After inserting the dilator (159) shown, the user can precisely control the advancement of the instrument at the distal tip for catheterization by rotating the advancement knob 195, thereby moving the device locking rod (and the axially attached instrument for catheterization) in a distal manner (extending the instrument toward and / or through the distal tip of the introducer sheath) or a proximal manner (retracting the dilator through and / or away from the distal tip of the introducer sheath). This in turn facilitates the performance of delicate operations (such as puncturing the atrial septum) in a very controlled manner.

[0101] The steerable introducer sheath assembly may also include an internal guide to prevent the device lock bar from improperly rotating with the advancement knob 195 about the axis 102 when rotated, which in turn ensures that when the user manipulates the advancement knob 195, the device lock bar moves along the axis 102 in an appropriate distal or lateral manner. For example, Fig. 9A and 9C As best shown in FIG. 1 , the inner guide 1950 may include a flat, cross-shaped distal base having a central hole defined by a hollow cylindrical rod extending in the proximal direction. Fig. 9B As best shown in FIG. 1 , the cross-shaped base of the inner guide 1950 allows it to be seated in a rotationally fixed manner within a guide channel defined by a set of parallel flanges 1927 extending inwardly from the inner surface of the upper handle portion 112 and a corresponding set of parallel flanges 1928 extending inwardly from the inner surface of the lower handle portion 114. The proximal end of the inner guide 1950 is also configured to engage a device locking rod in a rotationally fixed manner. For example, as Fig. 9CAs best shown in FIG. 1 , the engagement between the inner guide 1950 and the device locking rod can be regulated by one or more notches (1930) shown at the distal end of the locking rod 191a, which engage in a rotationally fixed manner with one or more side bosses 1929 extending proximally from the base of the inner guide 1950. In this manner, when the advance knob 195 is turned, rotational movement of both the inner guide and the externally threaded rod is prevented, thereby limiting the device locking rod from appropriate distal or proximal movement along the axis 102.

[0102] In certain embodiments, the handle portion 110 may include features that provide visual confirmation of the integrity of the seal between the hemostatic pilot valve 190 and the dilator 159 (or other catheter insertion instrument) that has been inserted through the hemostatic pilot valve 190 into the device lumen 140 of the introducer sheath 130. Fig. 8A As best shown in FIG. 1 , this can be accomplished by an opening 1931 in the upper housing portion 112, which is located proximal to the steering handle 160 and provides a "window" through which the distal side of the hemostatic pilot valve 190 can be viewed. By periodically inspecting the window 1121, the user can easily identify signs of compromised hemostatic seals between the hemostatic pilot valve 190 and the dilator 159 (or other catheter device) (including leakage of air, blood, or other fluids) and immediately take steps to correct the situation. The window 1931 can also allow the user to visualize both the rate at which the dilator is advanced and the extent to which the dilator is advanced, and to this end, the outer surface of the dilator (or other device for catheter insertion) can be marked with a gradient that can be viewed through the window 1931 to provide the user with an indication of the extent to which the dilator (or other device for catheter insertion) has been advanced into the introducer sheath (or retracted through the introducer sheath).

[0103] Certain embodiments of the present invention may include features for improving ultrasound visualization of catheterization instruments passing through introducer sheath 130 during a procedure. Instruments incorporating such features are qualitatively "brighter" than instruments without such features under the same imaging conditions in a given background medium or tissue, and are therefore easier to see during use. This makes it easier for the user to visualize placement and movement of the instrument, which in turn makes instrument utilization safer and more effective, particularly when the catheterization instruments involved have sharp points or edges or other features that could cause injury during use (e.g., in the case of Figure 8C and Fig.8D 150 is shown at an angle).

[0104] In certain embodiments, features for improving ultrasound visualization may include architectural modifications to the inner and / or outer surfaces of an instrument for catheter insertion utilized in conjunction with a steerable introducer sheath assembly according to the present disclosure ("ultrasound visualization modifications"). These ultrasound visualization modifications may include introducing one or more depressions or protrusions into the instrument for catheter insertion at locations where enhanced visibility is particularly desired. For example, the ultrasound visualization modification may include one or more dot-like depressions or protrusions that typically appear as clusters of "dots," which may be irregularly scattered or grouped and arranged in some regular configuration. The ultrasound visualization modification may also include one or more linear grooves or ridges that extend perpendicularly, parallel, at an angle, or in a spiral manner relative to the longitudinal center axis of the modified instrument.

[0105] In certain embodiments, ultrasound visualization modifications may be introduced specifically to the interior surface of an instrument for catheter insertion utilized in conjunction with a steerable introducer sheath assembly according to embodiments of the present disclosure. Placing ultrasound visualization modifications on the interior instrument surface may keep the exterior instrument surface smooth and free of irregularities, and thereby help prevent damage or undesirable changes to surrounding tissue that may be caused by external irregularities during introduction, manipulation, and / or withdrawal of an instrument for catheter insertion having external ultrasound visualization modifications. Limiting ultrasound visualization modifications to the interior instrument surface also prevents such modifications themselves from being altered or reduced in effectiveness through contact with potentially damaged surfaces, and also prevents structural damage or functional inhibition that may be affected by elements of the steerable introducer sheath assembly of the present disclosure due to contact with the modified exterior instrument surface (including, for example, damage to the introducer sheath and / or the centralized "device" lumen through which the instrument for catheter insertion passes).

[0106] Ultrasound visualization modifications may include any physical or structural alterations to an instrument that result in a subjective or objective improvement in ultrasound visibility of the modified instrument compared to an unmodified instrument. A subjective improvement of a modified instrument visualized using ultrasound may include a "brighter" or otherwise more distinct appearance compared to an unmodified instrument visualized under the same conditions. For example, as discussed further below, Fig. 10BUltrasound images of the distal tip of a dilator with improved visualization features according to an embodiment of the present disclosure (lower left and right images) are depicted as being qualitatively "brighter" relative to the distal tip of a prior art dilator (upper left and right images) where the distal tip is viewed under the same conditions against the same background medium. In light of this, any known method for obtaining and analyzing subjective observations of a person who has examined and compared the subjective appearance of test subjects viewed using comparable ultrasound techniques and conditions may be used to confirm the qualitative improvement in ultrasound visibility of an instrument with ultrasound visualization modifications according to the present disclosure (e.g., MA McCulloch et al., Limitations of Echocardiographic Periarterial Brightness in the Diagnosis of Kawasaki Disease, Am J Electrocardiol 18, 2005, pp. 768-770). For example, a series of ultrasound imaging sessions may be taken of both (i) instruments with ultrasound visualization modifications according to the present disclosure, and (ii) instruments without such modifications, as they are inserted into, manipulated within, or removed from standardized tissue or test media. Video clips of these imaging sessions may then be randomly compiled (with any potentially identifying information removed or blurred) and independently reviewed by experienced individuals (e.g., interventional radiologists, ultrasound technicians, cardiologists, or other specialized physicians with experience using the relevant instruments, etc.), who grade the qualitative "brightness" or "sharpness" of each instrument so imaged. The reviewer ratings are collated and processed, and statistical methods (such as Cohen's kappa coefficient and Wilcoxon rank sum test) are applied to confirm whether instruments with ultrasound visualization modifications are subjectively "brighter" or more distinctive than instruments without such modifications.

[0107] The relative improvement of ultrasound visualization can also be determined by using known methods for quantifying and comparing ultrasound signals returned by modified and unmodified instruments, including signal processing and measurement techniques designed to extract information from ultrasound echo signals returned by control and test articles. For example, D. Dalecki et al. recently identified and described some exemplary "[high] frequency ultrasound techniques, including elastic imaging techniques, [which] provide indicators for quantitative assessment of the structural, biological and mechanical properties of engineered constructs" (D. Dalecki et al., Quantitative Ultrasound for Nondestructive Characterization of Engineered Tissues and Biomaterials, 44 ANN. BlOMED. ENG'G, 636-648 (2016)). The use of such techniques can be further optimized by implementing computer-aided diagnosis methods, including, for example, machine learning algorithms, such as "training a classifier based on image recognition features and labeling images as normal versus abnormal" used by JY Wu et al. (JY Wu et al., Quantitative analysis of ultrasound images for computer-aided diagnosis, 3 J. MED. IMAGING, 014501-1-014501-9 (2016)). To this end, many commercially available software packages can be used with commercial ultrasound systems to identify, isolate, and quantify various image features. For example, QLAB advanced quantitative software purchased from Philips Medical Systems can be used in conjunction with commercial ultrasound systems to facilitate structural and functional echocardiographic analysis (IS Salgo, Clinical benefits of QLAB software for advanced 2D and 3D echoquantification, Kninkel Philips Electronics GmbH (2006)).

[0108] Given the above quantitative tools and methods (and others likewise known in the art), quantitative improvements in ultrasound visibility of instruments with ultrasound visualization modifications can be confirmed by first obtaining ultrasound imaging sessions of both: (i) instruments with ultrasound visualization modifications according to the present disclosure, and (ii) instruments without such modifications, when they are inserted into, manipulated within, or removed from standardized tissue or test media. For qualitative analysis, both video clips of these imaging sessions and the underlying acoustic information used to form the images are extracted for analysis by a skilled scientist or clinician. For example, an analyst may first define a region of interest (ROI) encompassing the portion of the instrument that has received ultrasound visualization modification, perhaps at a defined location within a standardized tissue or test medium or at a predefined time (e.g., one ROI is defined for each of the three phases of the experiment (insertion into, manipulation within, standardized tissue or test medium). After the ROIs are defined, the analyst may use a technique called densitometry to isolate the acoustic information underlying the image encompassed by the ROIs. These ROIs correspond to the relevant portions of the instrument (i.e., where ultrasound visualization was or was not added), after the original acoustic information underlying the original ROIs is thereby isolated. The raw acoustic information can then be processed to provide a quantitative assessment of the structural, biological, and mechanical properties of those instruments for catheter insertion that received ultrasound visualization modifications and compared to those instruments for catheter insertion that did not receive such modifications. These tests are collated and processed, and statistical methods (such as Cohen's kappa coefficient and Wilcoxon rank sum test) are applied as needed to confirm whether the instruments with ultrasound visualization modifications are quantitatively "brighter", more distinctive, or quantitatively improved relative to some other visual characteristic reflected in the isolated acoustic data compared to the instruments without ultrasound visualization modifications.

[0109] As described above, the ultrasound visualization modification may include one or more dot-like depressions or protrusions, which generally appear as a cluster of "dots," or as one or more linear grooves or ridges extending in a perpendicular, parallel, angled, or spiral manner relative to the longitudinal center axis of the modified device for catheter insertion. The linear grooves used to improve ultrasound visualization may be continuous or may be composed of smaller segments (which themselves may be coupled in a continuous end-to-end manner, or slightly separated, but still forming observable linear grooves). For example, Fig. 10A Depicted is a dilator (1920) for catheterization with a steerable introducer sheath assembly of the present disclosure, wherein the dilator has a distal opening of 0.033 inches, wherein as the dilator is extended in a proximal direction, the opening increases to a maximum inner bore diameter of at least 0.057 inches (note, Fig. 10AA representative depiction of a dilator 1920, which is not drawn to scale, is provided. Fig. 10A As shown, the dilator embodiment (1920) has been modified to improve ultrasound visualization by introducing three longitudinal grooves (1906) into the inner bore surface (1907) near the distal tip (1908), wherein the grooves are located 120 degrees apart from each other in a radial manner around the inner bore (e.g., Fig. 10A , upper left inset), and extend parallel to each other in a stepped manner in a distal to proximal direction, which is also parallel to the longitudinal axis 102 (as shown in FIG. Fig. 10A ). Each of the three grooves introduced into the expander 1920 has a groove width (1909) of 0.012 inches and a total groove length (1910) of 0.375 inches, which is further subdivided into six equal steps coupled end to end, wherein each step has a groove step length (1911) of 0.0625 inches and a groove step depth (1912) of 0.003 inches (as shown in FIG. Fig. 10A best shown in (main body and upper right inset)).

[0110] Including similar to Fig. 10A The ultrasound visualization modification shown in , helps to visualize instruments used for catheter insertion during procedures performed using ultrasound imaging. This can be done in Fig. 10B , which depicts ultrasound images obtained during the introduction (upper left) and removal (upper right) of a prior art dilator (which does not incorporate ultrasound visualization modifications), and Fig. 10A Ultrasound images obtained during introduction (lower left) and removal (lower right) of a dilator (1920) including the ultrasound visualization modification in the form of the stepped grooves described above are shown. Fig. 10B Compared to the appearance of the distal dilator tip indicated by arrows 1910 and 1911 (from the dilator of the prior art), the distal dilator tip indicated by arrows 1912 and 1913 (from the dilator having Fig. 10A The appearance of the "step-like groove" ultrasound visualization modified dilator depicted in and discussed herein shows a significant increase in brightness, which can be observed as a series of parallel "stripes" extending downward from the apparent location of the distal tip. This increased brightness in turn facilitates visualization of the distal tip of the dilator during surgery using ultrasound imaging.

[0111] In certain embodiments, the dilator 159 may also incorporate a barium-impregnated polymer that may enhance the fluoroscopic visibility of the dilator when introduced, for example, using a steerable introducer sheath assembly according to embodiments of the present disclosure.

Claims

1. An introducer sheath assembly, characterized in that: include: A handle portion, including a distal end and a proximal end; An introducer sheath extending outwardly from the distal end of the handle portion, the introducer sheath comprising: a device lumen configured to slidably receive a corresponding device; at least two steering cable lumens disposed radially outward from the device lumen; at least two steering cables attached to the distal end of the introducer sheath and disposed within the at least two steering cable lumens; a first steering assembly disposed in the handle portion and comprising an element to which a proximal end of at least one of the at least two steering cables is attached; and a second steering assembly disposed in the handle portion and comprising an element to which a proximal end of at least one of the at least two steering cables is attached; wherein the first steering assembly is manipulable to change the tension in a steering cable attached to the first steering assembly, and the second steering assembly is manipulable to change the tension in a steering cable attached to the second steering assembly; and A slack removal assembly for removing excess slack from a steering cable attached to a steering assembly when other steering assemblies are manipulated to change the tension of the steering cable to which they are attached, wherein the slack removal assembly further comprises: The first connecting arm, a second connecting arm, and First column; wherein the first connecting arm is rotatably linked to the second connecting arm via a fastener, the second connecting arm is rotatably connected to the first column via a fastener, and at least one steering assembly is engaged with the first connecting arm, the second connecting arm and the first column to remove excess slack from at least one of the steering cables attached to another steering assembly.

2. The introducer sheath assembly according to claim 1, characterized in that: The first and second connecting arms in a triangular configuration allow for a longer path for an attached steering cable while removing excess slack.

3. The introducer sheath assembly according to claim 1, characterized in that: The slack removal assembly includes a first slack removal assembly and / or a second slack removal assembly; the first steering cable passes through the first slack removal assembly, and the second steering cable passes through the second slack removal assembly.

4. The introducer sheath assembly according to claim 1, characterized in that: The second steering assembly also includes: An externally threaded rod, wherein the externally threaded rod engages a proximal end of a corresponding steering cable, the proximal end of the externally threaded rod being coupled to the slack removal assembly.

5. The introducer sheath assembly according to claim 4, characterized in that: in, The second steering assembly also includes: a distal cap rotatably disposed in an aperture in the distal end of the handle portion, wherein rotation of the distal cover relative to the externally threaded rod moves the externally threaded rod in a proximal direction or a distal direction parallel to the longitudinal center axis of the introducer sheath; and wherein rotation of the distal cover simultaneously changes the tension in the corresponding steering cables.

6. The introducer sheath assembly according to claim 5, characterized in that: in, The externally threaded rod also includes at least one axially extending groove, which engages with at least one axially extending flange extending from the inner surface of the handle portion, so that when the distal cover is rotated relative to the externally threaded rod, the externally threaded rod can only move in a proximal or distal direction parallel to the longitudinal center axis of the introducer sheath.

7. The introducer sheath assembly according to claim 4, characterized in that: The steering cables include a first steering cable, a second steering cable, a third steering cable, and a fourth steering cable; wherein the first steering cable and the second steering cable are attached to the first steering assembly; the third steering cable and the fourth steering cable being attached to the externally threaded rod in the second steering assembly; The slack removal assembly is used to remove excess slack from at least one steering cable attached to the first steering assembly when the second steering assembly is manipulated.

8. The introducer sheath assembly according to claim 1, characterized in that: Also included is a torque transfer lock that prevents the introducer sheath from rotating about the longitudinal center axis when the steering assembly is used to change tension in the at least one steering cable.

9. The introducer sheath assembly according to claim 8, characterized in that: The torque transfer lock also includes a hollow post having an inner diameter sufficient to enclose a radial diameter of the introducer sheath and at least one structure capable of engaging with at least one corresponding structure extending from a face of the handle portion to prevent the torque transfer lock from rotating about a longitudinal axis of the introducer sheath.

10. The introducer sheath assembly according to claim 1, characterized in that: The handle portion has an aperture therein that allows a user to visualize the point at which the corresponding device has been received into the device lumen of the introducer sheath.

11. The introducer sheath assembly according to claim 10, characterized in that: in, The corresponding device includes indicia that can be visualized through the aperture to provide an indication to a user of the extent to which the corresponding device has been inserted into the device lumen of the introducer sheath.

Images