Expandable transluminal sheath
View Patent ↗Disclosed is an expandable transluminal sheath, for introduction into the body while in a first, low cross-sectional area configuration, and subsequent expansion of at least a part of the distal end of the sheath to a second, enlarged cross-sectional configuration. The distal end of the sheath is maintained in the first, low cross-sectional configuration and expanded using a radial dilatation device. In an exemplary application, the sheath is utilized to provide access for a diagnostic or therapeutic procedure such as ureteroscopy or stone removal.
1. An expandable transluminal access sheath adapted for providing minimally invasive access to body lumens or cavities, comprising:
an axially elongate sheath tube with a proximal and a distal end and a central through lumen;
a distal region of the sheath which is expandable in circumference in response to pressure applied therein,
a hub affixed to the proximal end of the sheath tube, the hub adapted to form a tapered internal lumen to facilitate the passage of instrumentation;
a central obturator, which serves to occlude the central lumen of the sheath during insertion; and
a guidewire lumen within the obturator, capable of passing standard medical guidewires;
wherein the obturator is a balloon dilator capable of expanding the distal region of the sheath.
2. The transluminal sheath of claim 1 wherein the sheath tube comprises an outer layer, an inner layer, and a reinforcing layer wherein the outer layer and the inner layer comprises a polymer.
3. The transluminal sheath of claim 2 wherein the polymeric material is polyolefin.
4. The transluminal sheath of claim 2 wherein the polyolefin is selected from a blend of high-density and low-density polyethylene.
5. The transluminal sheath of claim 2 wherein the inner and outer layer are fabricated from different polymers.
6. The transluminal sheath of claim 2 wherein the inner or outer layer are fabricated from a blend of high-density and low-density polyethylene wherein the ratio is 25% of one polymer and 75% of the other polymer.
7. The transluminal sheath of claim 2 wherein the sheath bends predominantly by plastic deformation rather than elastic deformation.
8. The transluminal sheath of claim 2 wherein the sheath bends predominantly by plastic deformation, said deformation being enhanced by subjecting the sheath to temperatures substantially near those of body temperature.
9. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure fabricated from polymeric materials.
10. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure fabricated from polyethylene napthalate.
11. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure fabricated from polyethylene terephthalate.
12. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure fabricated from a blend of PET and PEN, wherein the ratio of PET to PEN varies from 0.1 to 0.9.
13. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure fabricated from polyamide.
14. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure with a pick count ranging between 10 and 30 picks per inch and between 8 and 42 carriers of strand.
15. The transluminal sheath of claim 2 wherein the reinforcing layer is a braided structure comprising fibers with primary diameters between 0.001 inches and 0.010 inches.
16. The transluminal sheath of claim 2 wherein the reinforcing layer is substantially deformable in cross-section.
17. The transluminal sheath of claim 2 wherein the sheath tube is substantially deformable in cross-section in response to irregularly shaped objects being advanced or withdrawn therethrough.
18. The transluminal sheath of claim 2 wherein the reinforcing layer is a coil of flat wire.
19. The transluminal sheath of claim 2 wherein the inner member, the reinforcing layer, and the outer member are fabricated from polymeric materials.
20. The transluminal sheath of claim 2 wherein the sheath comprises a radiopaque marker.