Bend-limited catheters

Abstract

Described herein are bend-limited catheters (e.g., apparatuses, including devices and systems) and methods of using them. These apparatuses may include an elongate tubular body that has one or more cut-out kerfs forming a pattern of interlocking teeth that are arranged in rings (and/or one or more spiral patterns) around the perimeter of the elongate tubular body. The pattern of interlocking teeth is configured to provide the catheter with a high degree of flexibility in bending, while permitting the device to lock at a locking diameter when the catheter bends to a minimum locking angle, beyond which no further bending is permitted.

What is claimed is: 
     
         1 . A bend-limited catheter device having a length extending in a long axis, the device comprising:
 a tubular body having one or more cut-out kerfs forming a pattern of interlocking and alternating teeth extending around the tubular body, the pattern repeating from a distal region to a proximal region of the tubular body, wherein each tooth of the interlocking and alternating teeth comprises a head region that is wider than a base region, arranged so that the head regions alternate with base regions radially around the tubular body, so that the tubular body bends in a direction out of a long axis of the bend-limited catheter device up to a locking radius, beyond which the tubular body does not allow further bending in the direction;   wherein each tooth of the interlocking and alternating teeth forms a tooth angle between a line extending through a width of the head region and a line extending from the head region and the base region;   further wherein a proximal portion of the pattern of interlocking and alternating teeth comprises teeth having an average tooth angle that is less than an average tooth angle of a more distal portion of the pattern of interlocking and alternating teeth.   
     
     
         2 . The device of  claim 1 , wherein the more distal portion of the pattern of interlocking and alternating teeth is configured to expand from a compressed elongate length by between about 0.005 inches and 0.085 inches per every 0.1 inch of the length of the pattern, further wherein the proximal portion is configured to expand from a compressed elongate length by less than the more distal portion of the pattern of interlocking and alternating teeth. 
     
     
         3 . The device of  claim 1 , wherein the more distal portion is immediately adjacent to the proximal portion. 
     
     
         4 . The device of  claim 1 , wherein the more distal portion of the pattern of interlocking and alternating keystone-shaped teeth extends more than 2 cm along the long axis, further wherein the proximal portion of the pattern of interlocking and alternating keystone-shaped teeth that extends more than 2 cm along the long axis. 
     
     
         5 . The device of  claim 1 , wherein the more distal portion of the pattern of interlocking and alternating teeth has a pitch to tubular body diameter ratio that is between 0.09 and 0.30 and a pitch to tubular body diameter ratio of the proximal portion of the pattern of interlocking and alternating keystone-shaped teeth that is between 0.30 and 0.90. 
     
     
         6 . The device of  claim 1 , wherein the more distal portion of the pattern of interlocking and alternating teeth comprises 20 or more teeth per revolution around a diameter of the tubular body, and wherein the proximal portion of the pattern of interlocking and alternating teeth comprises between 6-20 teeth per revolution around the diameter of the tubular body. 
     
     
         7 . The device of  claim 1 , wherein the teeth each form a keystone shape. 
     
     
         8 . The device of  claim 1 , wherein the one or more cut-out kerfs have a diameter of between 0.0005 and 0.002 inches. 
     
     
         9 . The device of  claim 1 , wherein the tubular body comprises one or more of: steel, tungsten, and Nitinol. 
     
     
         10 . The device of  claim 1 , further comprising a sealing material extending across the cut-out kerfs. 
     
     
         11 . The device of  claim 10 , wherein the sealing material is laminated to the tubular body. 
     
     
         12 . The device of  claim 10 , wherein the sealing material has a Shore A durometer hardness of greater than 75. 
     
     
         13 . The device of  claim 10 , wherein the sealing material is laminated to an inner surface of the tubular body. 
     
     
         14 . The device of  claim 10 , wherein the sealing material is laminated to an outer surface of the tubular body. 
     
     
         15 . The device of  claim 1 , further comprising an inflatable balloon on the bend-limited catheter device. 
     
     
         16 . The device of  claim 1 , wherein the locking radius of the more distal portion of the pattern of interlocking and alternating teeth is more than 15% smaller than the locking radius of the proximal portion of the pattern of interlocking and alternating teeth. 
     
     
         17 . The device of  claim 16 , wherein the locking radius of the proximal portion of the pattern of interlocking and alternating teeth is between 15 cm and 35 cm. 
     
     
         18 . A bend-limited catheter device having a length extending in a long axis, the device comprising:
 a tubular body having one or more cut-out kerfs forming a pattern of interlocking and alternating teeth extending around the tubular body, the pattern repeating from a distal region to a proximal region of the length of the tubular body, wherein each tooth of the interlocking and alternating teeth comprises a head region that is wider than a base region, arranged so that the head regions alternate with base regions radially around the tubular body, so that the tubular body bends in a direction out of a long axis of the catheter device up to a locking radius, beyond which the tubular body does not allow further bending in the direction;   wherein each tooth of the interlocking and alternating teeth form a tooth angle between a line extending through a width of the head region and a line extending from the head region and the base region;   further wherein a distal portion of the pattern of interlocking and alternating teeth comprises teeth having an average tooth angle that is greater than an average tooth angle of a more proximal portion of the pattern of interlocking and alternating teeth; and   wherein the distal portion of the pattern of interlocking and alternating teeth has a pitch to tubular body diameter ratio that is less than the pitch to tubular body diameter ratio of the more proximal portion of the pattern of interlocking and alternating teeth, wherein the pitch is a distance between adjacent rows of interlocking and alternating teeth along the long axis of the tubular body.   
     
     
         19 . A bend-limited catheter device having a length extending in a long axis, the device comprising:
 a tubular body having one or more cut-out kerfs forming a pattern of interlocking and alternating keystone-shaped teeth extending around the tubular body, the pattern repeating from a distal region to a proximal region of the length of the tubular body, wherein each keystone-shaped tooth of the interlocking and alternating keystone-shaped teeth comprises a head region that is wider than a base region, arranged so that the head regions alternate with base regions radially around the tubular body, so that the tubular body bends in a direction out of a long axis of the catheter device up to a locking radius;   wherein each keystone-shaped tooth of the interlocking and alternating keystone-shaped teeth form a tooth angle between a line extending through a width of the head region and a line extending from the head region and the base region;   further wherein a distal portion of the pattern of interlocking and alternating keystone-shaped teeth that extends more than 2 cm along the length of the long axis comprises keystone-shaped teeth having a tooth angle that is between 61-84 degrees, and a proximal portion of the pattern of interlocking and alternating keystone-shaped teeth that extends more than 2 cm along the length of the long axis comprises keystone-shaped teeth having a tooth angle that is between 30 to 60 degrees; and   wherein the distal portion of the pattern of interlocking and alternating keystone-shaped teeth has a pitch to tubular body diameter ratio that is between 0.09 and 0.30 and a pitch to tubular body diameter ratio of the more proximal portion of the pattern of interlocking and alternating keystone-shaped teeth is between 0.30 and 0.90, wherein pitch is a distance between adjacent rows of interlocking and alternating teeth along the long axis of the tubular body and the tubular body diameter is the diameter of the tubular body transverse to the adjacent rows of interlocking and alternating teeth.