Shielded tip catheter for lithotripsy

A device for impacting a formation within a body passage comprising:

• an elongate flexible member for insertion into the body passage;
• a housing defining a proximal end and a distal end, the proximal end of said housing being coupled to the elongate flexible member such that, in an operative position, the housing is located within the body passage;
• a pair of electrodes located within said housing and defining a spark gap disposed within said housing;
• means for introducing liquid into the housing;
• a piston, defining an impact element extendable beyond the distal end of said housing, said piston being mounted for axial reciprocating movement within said housing such that, in response to a spark being generated across said spark gap, said piston moves axially within said housing away from the distal end of said housing, wherein the piston includes a central lumen and a port formed in a distal portion of the piston to permit the passage of liquid through the piston;
• and
• a shock absorbing element disposed between said piston and said elongate flexible member for inhibiting transmission of vibrations along said flexible member.

A device for impacting a formation in a body passage comprising:

• an elongate flexible member for insertion into a body passage;
• a housing defining a proximal end and a distal end, the proximal end of said housing being coupled to the elongate flexible member such that, in an operative position, the housing is located within the body passage;
• a pair of electrodes located within said housing and defining a spark gap disposed within said housing;
• a piston, defining an impact element and a driving surface, said piston being mounted for axial reciprocating movement between a rest position and a formation contact position, said piston being mounted in said housing such that, upon a discharge from said electrodes, said piston is driven from said rest position into said formation contact position, and wherein said driving surface is disposed adjacent to said pair of electrodes when said piston is in said rest position, wherein the piston includes a central lumen and a port formed in a distal portion of the piston to permit the passage of liquid through the piston;
• means for introducing liquid into the housing;
• and
• a spring disposed within the housing, the spring being located between the piston and the housing, wherein the spring is biased to return said piston to said rest position after a discharge from said electrodes has driven the piston into said formation contact position.

A device for impacting a formation in a body passage comprising:

• an elongate flexible member for insertion into a body passage;
• a cylindrical housing, comprising a proximal end and a distal end, the proximal end of the housing being attached to a distal end of the flexible member such that, in an operative position, the housing is located within the body passage, the housing forming an extension of the flexible member and defining an opening at a distal end thereof;
• a pair of electrodes defining a spark gap disposed within a tube which is attached to an inner surface of the housing;
• means for introducing liquid into the housing;
• a retractable probe having an impact end including a cutting surface and a driving end, the probe being mounted for reciprocal movement within the housing such that, upon the generation of a spark across the spark gap, the probe moves axially away from a retracted position so that the cutting surface extends from the distal end of the housing;
• and
• means for returning the probe to the retracted position.