Endoscopic lithotripsy system

Abstract

An endoscopic lithotriptor including an elongated, flexible stone impacting member in the form of a wire whose distal end is brought against a stone to be broken and whose proximal end is adapted to be periodically struck by a hammer element. The hammer element is pneumatically driven by a linear jet of air causing it to swing through an arc about a pivot to impact an anvil affixed to the wire and oriented tangentially to the arc swept out by the hammer. The pneumatic chamber structure in which the hammer is pivotally mounted is designed to maximize the angular velocity reached by the hammer before impacting the anvil.

What is claimed is:  
     
       1. A lithotripsy device comprising: 
       (a) an elongated, stone impacting member having a distal end for engaging a calculus and a proximal end;  
       (b) hammer means for repetitively applying an impact force to said stone impacting member, said hammer means including a chamber having a hammer member rotatably mounted therein and rotatable between a first ready position displaced from said proximal end of said stone impacting member and a second position in contact with said proximal end of said stone impacting member;  
       (c) means for driving said hammer member from said first ready position forcefully against said stone impacting member in said second position to drive said distal end of said stone impacting member against said calculus; and  
       (d) means for returning said hammer member to said first ready position.  
     
     
       2. The lithotripsy device as in claim  1  wherein said chamber is a pneumatic chamber. 
     
     
       3. The lithotripsy device as in claim  2  and further including means for releasably restraining said hammer member in said first ready position until a desired pressure is built up in a portion of said pneumatic chamber. 
     
     
       4. The lithotripsy device of claim  3  wherein said pneumatic chamber comprises a block of material having a cavity formed therein, said cavity including an arcuate segment containing said rotatably mounted hammer member, a capacitance segment in fluid communication with said arcuate segment through a narrow slit formed at a juncture of said capacitance segment with said arcuate segment and located adjacent said hammer member when in said first ready position and a pressure relief segment in fluid communication with said arcuate segment located adjacent said hammer member when in said second position. 
     
     
       5. The lithotripsy device as in claim  4  and further including a seal member surrounding said narrow slit adapted to cooperate with said hammer member when said hammer member is in said first ready position. 
     
     
       6. The lithotripsy device as in claim  4  and further including a high pressure gas inlet communicating with said capacitance segment and a gas outlet communicating with said pressure relief segment. 
     
     
       7. The lithotripsy device as in claim  4  wherein said means for releasably restraining said hammer member comprises a pneumatic cylinder mounted in said block having a piston rod extendable and retractable relative to said pneumatic cylinder, said piston rod being disposed in a path of travel of said hammer member when said hammer member is in said first ready position and out of said path of travel when retracted. 
     
     
       8. The lithotripsy device as in claim  4  wherein said means for releasably restraining said hammer member comprises a spring-loaded ball detent mounted in said block, said ball engaging said hammer member when said hammer member is in said first ready position. 
     
     
       9. The lithotripsy device as in claim  4  wherein said stone impacting member has an outer diameter of a size capable of passing through a working lumen of one of a rigid endoscope and a flexible, steerable-tip endoscope when said block of material is coupled to a handle of the endoscope. 
     
     
       10. The lithotripsy device as in claim  4  and further including means for mounting said block of material to an endoscope, said means for mounting including means for adjusting an extent by which said distal end of said stone impacting member extends beyond a distal end of said endoscope. 
     
     
       11. The lithotripsy device as in claim  10  wherein said means for mounting includes means for releasably latching said block of material to said endoscope at any one of a plurality of positions. 
     
     
       12. The lithotripsy device as in claim  1  wherein said stone impacting member is a flexible metal wire. 
     
     
       13. The lithotripsy device as in claim  12  and further including an elongated flexible, sheath surrounding said flexible metal wire. 
     
     
       14. The lithotripsy device as in claim  13  wherein said sheath is made of material selected from a class including stainless steel, Nitinol, polyimid plastic and PTFE plastic. 
     
     
       15. The lithotripsy device as in claim  13  wherein said sheath has an outer diameter of a size capable of passing through a working lumen of one of a flexible steerable tip endoscope and a rigid endoscope. 
     
     
       16. The lithotripsy device as in claim  13  wherein said sheath has an outer diameter of a size capable of passing through a working lumen of one of a rigid endoscope and a flexible, steerable-tip endoscope when said block of material is coupled to a handle of the endoscope. 
     
     
       17. The lithotripsy device as in claim  4   12 wherein said flexible metal wire is formed from a metal selected from a class includinggroup consisting of stainless steel and Nitinolshape memory alloy. 
     
     
       18. The lithotripsy device as in claim  12  wherein said wire is in the range of from about 8 cm to 122 cm in length. 
     
     
       19. The lithotripsy device as in claim  1  and further including an anvil member affixed to said proximal end of said stone impacting member and means cooperating with said anvil member for limiting the extent of travel of said anvil member when impacted by said hammer member. 
     
     
       20. The lithotripsy device according to claim  17  wherein said shape memory alloy is Nitinol.  
     
     
       21. A lithotripsy device comprising: 
       
         a flexible elongated stone impacting member having a distal end for contacting a calculus, and a proximal end;  
       
       
         a hammer for repetitively applying an impact force to the stone impacting member, rotatably mounted in a chamber and rotatable between a first position displaced from the proximal end of the stone impacting member and a second position in contact with the proximal end of the stone impacting member; and  
       
       
         a mechanism to drive the hammer from the first position into the second position and from the second position into the first position.  
       
     
     
       22. The lithotripsy device according to claim  21 , wherein the flexible elongated stone impacting member is fabricated from one of stainless steel, Nitinol, and a combination of Nitinol and stainless steel.  
     
     
       23. The lithotripsy device according to claim  21 , wherein the flexible elongated stone impacting member is detachable from the rest of the lithotripsy device.  
     
     
       24. The lithotripsy device according to claim  21 , further comprising a flexible elongated tubular sheath surrounding the elongated stone impacting member.  
     
     
       25. The lithotripsy device according to claim  24 , wherein the flexible elongated tubular sheath is formed from a lubricious material.  
     
     
       26. The lithotripsy device according to claim  24 , wherein the flexible elongated tubular sheath is formed from a group consisting of stainless steel, polyimid plastic, PTFE plastic, and Nitinol.  
     
     
       27. The lithotripsy device according to claim  24 , wherein the distal end of the flexible elongated stone impacting member extends beyond a distal end of the flexible elongated tubular sheath.  
     
     
       28. The lithotripsy device according to claim  21 , wherein said mechanism comprises a pneumatic power source.  
     
     
       29. A method of impacting stones in the body using a lithotripsy device, the method comprising the steps of: 
       
         inserting an endoscope into an area of the body to be treated;  
       
       
         providing a driving force to a hammer rotatably mounted in a lithotripsy device, which causes the hammer to rotate and contact a flexible stone impacting member; and  
       
       
         repetitively providing a stone impacting force from the hammer to the flexible stone impacting member.  
       
     
     
       30. The method of impacting stones in the body according to claim  29 , further comprising the step of advancing the endoscope through the urethra and into the ureters.  
     
     
       31. The method of impacting stones in the body according to claim  29 , wherein said providing step comprises providing the driving force which comprises a pneumatic force.  
     
     
       32. The method of impacting stones in the body according to claim  29 , wherein the endoscope is inserted percutaneously.  
     
     
       33. The method of impacting stones in the body according to claim  29 , wherein the endoscope is inserted intracorporeally.  
     
     
       34. The method of impacting stones in the body according to claim  29 , wherein the flexible stone impacting member is fabricated from one of stainless steel, Nitinol, and a combination of Nitinol and stainless steel.  
     
     
       35. The method of impacting stones in the body according to claim  29 , wherein the flexible stone impacting member is detachable from the rest of the lithotripsy device.  
     
     
       36. A pneumatic lithotripsy device, comprising: 
       
         a flexible elongated stone impacting wire including a distal end for containing a calculus, and a proximal end, the flexible elongated stone impacting wire comprising a shape memory alloy and capable of being curved into a body lumen;  
       
       
         a housing comprising a hammer for repetitively applying an impact force to the stone impacting wire, the hammer including a chamber having a hammer member mounted therein and positionable between a first position displaced from the proximal end of the stone impacting wire and a second position in contact with the proximal end of the stone impacting wire;  
       
       
         a pneumatic hammer driver providing a driving force to place the hammer member in the first and second positions; and  
       
       
         a flexible elongated tubular sheath attached to said housing and surrounding at least a portion of the flexible elongated stone impacting wire.  
       
     
     
       37. The lithotripsy device of claim  36  wherein said shape memory alloy is Nitinol.  
     
     
       38. The lithotripsy device according to claim  36 , wherein the flexible elongated stone impacting wire is detachable from the rest of the lithotripsy device.  
     
     
       39. The lithotripsy device according to claim  36 , wherein the flexible elongated tubular sheath is formed from a lubricious material.  
     
     
       40. The lithotripsy device according to claim  36 , wherein the flexible elongated tubular sheath is formed from a group consisting of stainless steel, polyimid plastic, PTFE plastic, and Nitinol.  
     
     
       41. The lithotripsy device according to claim  36 , wherein the distal end of the flexible elongated stone impacting wire extends beyond a distal end of the flexible elongated tubular sheath.  
     
     
       42. The lithotripsy device of claim  36  wherein said stone impacting wire has a diameter of  0 . 020  inches.  
     
     
       43. The lithotripsy device of claim  36  wherein said stone impacting wire has portions which are flattened.  
     
     
       44. The device of claim  36  wherein said flexible elongated sheath comprises stainless steel and plastic.  
     
     
       45. A method of impacting stones in the body using a pneumatic lithotripsy device, comprising: 
       
         inserting an endoscope into an area of the body to be treated;  
       
       
         providing a pneumatic driving force to a hammer mounted in a housing of a lithotripsy device which causes the hammer to move from a first position displaced from the proximal end of a flexible elongated stone impacting wire to a second position in contact with the proximal end of the flexible elongated stone impacting wire; and  
       
       
         repetitively providing a stone impacting force from the hammer to the flexible elongated stone impacting wire which comprises a shape memory alloy and which contacts a stone to be treated, wherein the flexible elongated stone impacting wire extends through and is capable of being curved into a working lumen of the endoscope and at least a portion of the flexible elongated stone impacting wire is surrounded by a flexible elongated sheath attached to said housing.  
       
     
     
       46. The method of impacting stones in the body according to claim  43 , further comprising the step of advancing the endoscope through the urethra and into the ureters after the endoscope is inserted into the body.  
     
     
       47. The method of impacting stones in the body according to claim  45 , wherein the endoscope is inserted percutaneously.  
     
     
       48. The method of impacting stones in the body according to claim  45 , wherein the endoscope is inserted intracorporeally.  
     
     
       49. The method of impacting stones in the body according to claim  43 , wherein the flexible elongated stone impacting wire is detachable from the rest of the lithotripsy device.