Curved ureteral channel sheath

Abstract

A ureteral channel sheath (UAS) is provided. The UAS includes an elastically deformable tube having a shape memory that includes an arcuate bend at a head end thereof that corresponds to an anatomical shape of a ureter inlet up to and through a junction into a renal cavity (renal pelvis), and an introduction funnel at a tail end of the tube. The UAS further comprises a corresponding dilator provided with a tubular body having a shape memory, the shape of which comprises an arcuate bend at the head end thereof, the arcuate bend substantially corresponding to the curved shape of the elastically deformable tube of the UAS.

Description

Technical Field

[0001] This invention relates to a ureteral access sheath (UAS). Background Technology

[0002] Ureteral access sheaths are used in the field of endourology as a device to provide a non-invasive passage to the patient's kidney for flexible surgical instruments such as endoscopes during intrarenal surgeries, such as the treatment of kidney stones, and to facilitate flushing and drainage of the kidney during such procedures.

[0003] Existing ureteral access sheaths are thin-walled, fairly rigid but flexible straight tubes that are inserted into the ureter using a technique known as the Seldinger technique, together with a tipped dilator fitted onto a guidewire. The ureteral access sheath is inserted through the ureter from the bottom (in the retrograde direction) and is positioned at or below the uretero-pelvic junction (PUJ), or just through the junction into the renal pelvis.

[0004] The inventors point out several difficulties and problems with existing renal artery septa (UAS). First, when the UAS is placed below the ureteral fistula (PUJ), it may become occluded or partially occluded due to the valve structure formed by the loose tissue flap or due to ureteral stenosis. Second, although this is not recommended due to the straight shape of the UAS, if the UAS is inserted further beyond the PUJ, it may be blocked by the curvature of the upper ureter; or third, if inserted even deeper, it may be blocked by the top or wall of the renal pelvis. Since the first part (main part) of the ureter is usually straight, a straight-shaped UAS is necessary.

[0005] Furthermore, up to 50% of UAS insertions result in ureteral injury, most of which is caused by the edge of the ureteral sheath. The UAS is inserted into the kidney along with a dilator that fits tightly inside the UAS. The dilator has a central tubular hollow portion through which at least one guidewire passes. The dilator is slid along the guidewire using the Seldinger technique. Known dilators have a flexible, tapered tip to aid in ureteral dilation. The outer diameter of the dilator and its tip is slightly smaller than the inner diameter of the ureteral channel sheath to allow easy insertion and removal of the dilator from the channel sheath. This difference between the outer diameter of the dilator and the inner diameter of the ureteral channel sheath creates an exposed shaving edge, especially when the tip of the dilator bends as it traverses the meandering anatomy of the ureter. This shaving edge can cause damage to the ureteral mucosa.

[0006] The purpose of this invention is to solve the aforementioned problems and difficulties. Summary of the Invention

[0007] According to the present invention, a ureteral access sheath (UAS) is provided, comprising: A shape-memory, elastically deformable tube, the shape of which includes an arcuate bend at its tip corresponding to the anatomical shape of the ureteral inlet up to and through the junction into the renal cavity (renal pelvis); and An inlet funnel located at the tail end of the tube.

[0008] The UAS may include a corresponding expander having a shape-memory tubular body, the shape of which optionally includes an arcuate bend at its head end, the arcuate bend roughly corresponding to the bending shape of the elastic deformable tube of the UAS.

[0009] The expander includes an expander handle or expander clamp at its tail end, which allows the user to rotate the expander within the UAS tube. Multiple indicator marks may be provided on the handle or clamp and the inlet funnel to indicate when the UAS and expander are in their natural resting shapes, and / or when the expander is oriented 180 degrees opposite to each other, such that the shapes of the UAS and expander cancel each other out to provide a generally straight UAS for initial insertion.

[0010] It should be understood that the present invention allows the shape of the UAS to be manipulated during insertion so as to begin with a generally straight UAS, wherein the respective memory shapes of the tube and the dilator are in opposite directions; and when the curved portion of the ureter is reached, the dilator can be rotated so that the memory shapes are oriented to form an arcuate curve corresponding to the ureteral anatomy. The dilator can then be removed, leaving the channel sheath in the correct anatomical orientation and shape.

[0011] The head edge of the UAS tube is preferably rounded or chamfered from the inner edge of the head edge toward the outer surface of the tube.

[0012] It should be understood that the tube is made of a known surgically acceptable material, has standard UAS dimensions, a width ranging from 8F to 16F, and possesses the required physical properties, such as stiffness, kink resistance, etc. The tube preferably may include an inner Teflon layer, a stainless steel coil in the middle layer for reinforcement, and an outer layer of Pebax or polyurethane.

[0013] It should be understood that the inlet funnel is intended to provide a channel for dilators, ureteroscopes, etc., to enter the UAS.

[0014] The dilator may have a tip made of a flexible, compliant, and shape-memory deformable soft thermoplastic polyurethane. This generally conical tip comprises two parts: a pointed tip with a rounded, conical shape, integrally formed with a truncated cone-shaped tail portion, wherein the pointed tip is longer than the tail portion, and wherein the tail portion has a sharper cone angle relative to the axis of the tube than the pointed tip. It should be understood that the pointed tip will be more flexible, compliant, and deformable than the tail portion, which facilitates the tip's non-invasive passage through the meandering ureter.

[0015] The tail diameter of the shape-memory deformable tip is preferably larger than the inner diameter of the UAS tube, such that when the tip is in the working position, the tail surface of the tip extends outward beyond the tip edge of the tube to shield the tip edge. It should be understood that this feature shields the inner wall of the ureter during use, preventing it from scraping against the edge formed by the tip edge of the tube, significantly reducing trauma to the ureteral mucosa. This advantage can be increased if the edge of the tube is rounded or chamfered as described above. The dilator is tubular to accommodate the guidewire passing through it.

[0016] The present invention also relates to an expander as described above.

[0017] The present invention also relates to a ureteral access system comprising the UAS as described above and the dilator as described above. Attached Figure Description

[0018] The present invention will now be described by way of example and with reference to the accompanying drawings.

[0019] In the attached diagram: Figure 1 A side view of a ureteral access sheath according to the present invention is shown.

[0020] Figure 2 A side view of a dilator for the ureteral access sheath according to the present invention is shown.

[0021] Figure 3 A side view of the ureteral access sheath according to the invention is shown, wherein the dilator is inserted in the same orientation.

[0022] Figure 4 A side view of the ureteral channel sheath according to the invention is shown, wherein the dilator is inserted in opposite orientation to straighten the channel sheath.

[0023] Figure 5 A detailed side view of the dilator tip extending from the ureteral canal sheath according to the present invention is shown. Detailed Implementation

[0024] Referring now to the accompanying drawings, the ureteral access sheath according to the invention is generally indicated by reference numeral 10.

[0025] The ureteral access sheath (UAS) 10 includes an elastic deformable tube 12 with shape memory, the shape of which includes an arcuate bend 14 at its tip to correspond to the anatomical shape of the ureter up to the junction into the renal cavity (renal pelvis); and an inlet funnel 16 located at the tail end of the tube 12.

[0026] The UAS10 includes a corresponding expander 18, which has a shape-memory tubular body 20, the shape of which includes an arc bend 22 at the head end of the expander, the arc bend 22 roughly corresponding to the bend 14 of the UAS10.

[0027] The dilator 18 includes a dilator clamp 24 at its tail end, which allows the user to rotate the dilator within the UAS tube 12. A plurality of indicator marks 26.1 and 26.2 may be provided on the clamp 24 and the inlet funnel 16 to indicate when the shapes of the UAS 10 and the dilator 18 correspond to their natural rest shapes (FIG. 3), and / or when the dilator 18 is oriented 180 degrees opposite to each other, such that the shapes of the UAS 10 and the dilator 18 cancel each other out to provide a generally straight UAS 10 for initial insertion (FIG. 4). The dilator is tubular to accommodate a guide wire 19 passing through it.

[0028] The head edge of the UAS tube 18 is rounded from the top of the inner edge toward the outer surface of the tube.

[0029] The tube comprises a polytetrafluoroethylene (PTFE) liner, a stainless steel reinforcing coil, and an outer layer made of polyurethane or Pebax. In another embodiment, a single extrusion of any of the aforementioned polymer materials can be used.

[0030] The inlet funnel 16 is designed to provide a channel for the dilator 18, ureteroscope, etc., to enter the UAS 10.

[0031] The dilator 18 is provided with a tip 28 made of a flexible, compliant, and elastically deformable material such as polyurethane (e.g., Tecoflex). This generally conical tip comprises two parts: a pointed tip 30.1 having a rounded, pointed conical shape, which is integrally formed with a truncated cone-shaped tail tip 30.2, wherein the pointed tip is longer than the tail tip, and wherein the tail tip has a sharper cone angle relative to the axis of the tube than the pointed tip. It should be understood that the pointed tip 30.1 of the tip 28 will be more flexible than the tail tip 30.2, which facilitates the tip's non-invasive passage through the meandering ureter.

[0032] The tail portion 30.2 of the deformable tip 28 has a tail diameter larger than the inner diameter of the UAS tube 12, such that when the tip is in the working position, the tail surface of the tip extends outward beyond the head edge of the tube 12 to cover the head edge of the tube. Despite the protrusion with a diameter wider than the inner diameter of the tube 12, the expander 18 can still be easily inserted into the tube 12 due to the soft deformability of the expander tip 28.

[0033] It should be understood that these embodiments are provided to further illustrate the present invention and to assist those skilled in the art in understanding the present invention, and should not be construed as unduly limiting the reasonable scope of the present invention.

Claims

1. A ureteral access sheath comprising: comprising: an elastically deformable tube with shape memory, the shape of which comprises a circular arc bend at its head end, which corresponds to the anatomical shape of the ureteral entry up to and through the junction into the renal cavity (renal pelvis); and an introduction funnel at the tail end of the tube.

2. The ureteral access sheath of claim 1, wherein: The ureteral access sheath comprises a respective dilator provided with a tubular body with shape memory, the shape of which comprises a circular arc bend at its head end, which substantially corresponds to the curved shape of the elastically deformable tube of the ureteral access sheath.

3. The ureteral access sheath of either of claims 1 or 2, wherein: The dilator comprises a dilator handle or dilator clamp at its tail end, which allows the user to rotate the dilator within the UAS tube.

4. The ureteral access sheath of claim 3, wherein: The dilator handle or dilator clamp comprises a plurality of indication markings to indicate when the shape of the UAS and dilator corresponds to their natural resting shape, and / or when the dilator is oriented 180 degrees opposite, such that the shape of the UAS and dilator cancel each other out to provide a substantially straight UAS for initial insertion.

5. The ureteral access sheath of any of claims 2-4, wherein: The head end edge of the UAS tube is rounded or chamfered from the inner edge of the head end edge towards the outer surface of the tube.

6. The ureteral access sheath of any of claims 2-5, wherein: The dilator is provided with a tip made of a flexible, compliant and shape memory deformable soft thermoplastic polyurethane, the substantially conical tip comprising a two-part shape, the head end part of which has a rounded, circular conical shape with a rounded tip, which is integrally formed with a tail end part in the shape of a right circular truncated cone, wherein the head end part is longer than the tail end part, and wherein the conical angle of the tail end part relative to the axis of the tube is sharper than the head end part.

7. The ureteral access sheath of claim 6, wherein: The tail end diameter of the tail end part of the tip with shape memory deformable is larger than the inner diameter of the UAS tube, such that when the tip is in the working position, the tail end surface of the tip extends beyond the head end edge of the tube outwardly to mask the head end edge of the tube.

8. A dilator, comprising: The dilator is provided with a tubular body with shape memory, the shape of which comprises a circular arc bend at its head end to substantially correspond to the curved shape of the elastically deformable tube of the ureteral access sheath as claimed in any one of claims 1 to 7.

9. A ureteral access system, comprising: The system comprises a ureteral access sheath as claimed in any one of claims 1 to 7 and a dilator as claimed in claim 8.

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