JPWO2021151070A5 - - Google Patents

Claims (15)

an inner layer forming a lumen;
an intermediate layer forming an annular lumen and surrounding the inner layer, the annular lumen of the intermediate layer being fluidly connected to a vacuum source;
an outer layer surrounding the intermediate layer,
A variable stiffness catheter, wherein applying a vacuum to evacuate the annular lumen of the intermediate layer changes the frictional resistance or adhesion between the inner layer and the outer layer, thereby changing the bending stiffness of the catheter. The variable stiffness catheter of claim 1, wherein the intermediate layer has a low bending stiffness or shear resistance when no vacuum is applied and a high bending stiffness or shear resistance when a vacuum is applied. the low bending stiffness or shear resistance of the catheter is due to continuous full microfluidic patency of the annular lumen connecting to a vacuum source;
3. The variable stiffness catheter of claim 2, wherein the high bending stiffness or shear resistance of the catheter is due to frictional or adhesive forces created when the vacuum source is applied. The variable stiffness catheter of claim 1 , wherein evacuation of the annular lumen of the intermediate layer changes the bending stiffness or adhesion of the intermediate layer . Evacuation of the annular lumen of the intermediate layer results in an increase in frictional resistance or adhesion that allows the inner layer, the intermediate layer and the outer layer to flex as if they were a single layer, thereby 5. The variable stiffness catheter of claim 4, wherein the bending stiffness of the inner layer, the middle layer, and the outer layer is increased by more than the sum of their bending stiffnesses. The variable stiffness catheter of claim 1, wherein there is a variable frictional resistance or adhesion between the contact surfaces of the inner layer and the outer layer on the intermediate layer. The variable stiffness catheter of claim 1, wherein the catheter has a variable stiffness along the length of the catheter between a proximal end and a distal end of the catheter. 8. The variable stiffness catheter of claim 7, wherein the catheter has variable stiffness along one or more portions of the catheter's length. 9. The variable stiffness catheter of claim 8, wherein the position of the variable stiffness portion of the catheter is optimized for a particular surgical procedure. 8. The variable stiffness catheter of claim 7, wherein the variable stiffness is along an asymmetric side of one or more portions of the catheter's length. The variable stiffness catheter of claim 1, wherein a plurality of strings are within the annular lumen. 12. The variable stiffness catheter of claim 11, wherein the plurality of strings are in a helical or linear configuration along the length of the inner layer. The variable stiffness catheter of claim 1, wherein the inner layer is relatively inflexible and the outer layer is relatively flexible. The variable stiffness catheter of claim 1, wherein the inner layer further includes a braid on its outer surface. The variable stiffness catheter of claim 1, further comprising a casing surrounding the outer layer.