Atraumatic ureteral access sheath
Ureteral access sheaths can have a nonuniform axial-stiffness. A nonuniform axial-stiffness ureteral access sheath can have an inner liner defining a longitudinally extending and generally uniform bore. A non-uniform axial-stiffness outer jacket can define a longitudinally tapered outer surface, and a reinforcement layer can be encapsulated between the inner liner and the non-uniform axial-stiffness outer jacket. The reinforcement layer can have a non-uniform axial-stiffness. For example, a proximal portion of the reinforcement layer can be thicker than a distal portion of the reinforcement layer. A coil of wire can be included in the reinforcement layer, and a diameter of the wire in a proximal portion of the reinforcement layer can be larger than a diameter of the wire in a distal portion of the reinforcement layer. In some instances, the diameter of the wire tapers from the proximal portion to the distal portion.
1. A non-uniform axial-stiffness ureteral access sheath, comprising:
an inner liner;
a reinforcement layer adjacent the inner liner; and
an outer jacket adjacent the reinforcement layer and having an outer surface tapered along its length, the outer jacket comprising:
a first proximal jacket portion having a first end and an opposing second end;
a second distal jacket portion having a first end and an opposing second end;
wherein the second jacket portion has a lower durometer than the first jacket portion, the first and second jacket portions have the same uniform thickness and the first end of the second jacket portion section abuts the second end of the first jacket portion.
2. The ureteral access sheath of claim 1 , wherein the reinforcement layer is a coil having a tapered outer diameter and uniform inner diameter.
3. The ureteral access sheath of claim 2 , wherein the coil is a metal.
4. The ureteral access sheath of claim 2 , wherein the coil is both a metal and a polymer.
5. The ureteral access sheath of claim 2 , wherein the coil has a diameter which varies from a proximal portion to a distal portion along the length of the longitudinal axis of the reinforcement layer.
6. The ureteral access sheath of claim 2 , wherein the coil is a round or a flat coil.
7. The ureteral access sheath of claim 2 , wherein the coil comprises angled or circumferential windings.
8. The ureteral access sheath of claim 2 , wherein the coil has a pitch and a diameter that vary from a proximal portion to a distal portion along the length of the longitudinal axis of the ureteral access sheath.
9. The ureteral access sheath of claim 1 , wherein the reinforcement layer comprises a tapered tubular mesh.
10. The ureteral access sheath of claim 1 , wherein the reinforcement layer is at least partially occupied by a radiopaque element.
11. The ureteral access sheath of claim 1 , wherein the reinforcement layer comprises a reinforcing composite material.