Electrode arrangement for a surgical instrument for electrothermal coagulation in tissue

Abstract

There is provided a surgical instrument for electrothermal coagulation of tissue, which includes a front cylinder at the distal end of the instrument having a distal tip, an elongate carrier, and two spaced cylindrical or strip-shaped electrodes at or on the carrier which are connectable to an HF-ac voltage source.

1 . An electrode arrangement for a surgical instrument for electrothermal coagulation in tissue, including
 a front cylinder at the distal end of the instrument,   at least one elongate, electrically insulating carrier proximally behind the front cylinder,   two spaced cylindrical electrodes,   a hollow duct in the longitudinal direction through the carrier, and   connecting lines which are passed through the hollow duct for connecting the electrodes to an AC voltage source,   characterized in that the electrodes are cylindrical tube portions of metal which are arranged at a predetermined spacing from each other in the longitudinal direction in axial alignment with the carrier.   
   
   
       2 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the carrier is a flexible tube of insulating material. 
   
   
       3 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that provided as a prolongation of the hollow duct is a central opening in the front cylinder, in which is arranged a temperature sensor whose connecting line is taken out through the hollow duct to the proximal end of the instrument. 
   
   
       4 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the outside diameter of the front cylinder approximately corresponds to the outside diameter of the electrodes. 
   
   
       5 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the axial length of the electrodes is larger than their diameter. 
   
   
       6 . An electrode arrangement for a surgical instrument as set forth in  claims 1  characterized in that the axial length of the electrodes is larger than double their diameter. 
   
   
       7 . An electrode arrangement for a surgical instrument as set forth in claims  42  characterized in that the spacing of the two electrodes is approximately equal to or smaller than the outside diameter of the electrodes. 
   
   
       8 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the distal front cylinder comprises insulating material or metal. 
   
   
       9 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the temperature sensor in the opening in the front cylinder is embedded in a synthetic resin or adhesive bed. 
   
   
       10 . An electrode arrangement for a surgical instrument as set forth in  claim 9  characterized in that the outside diameter of the electrodes corresponds to the outside diameter of the front cylinder and that the intermediate space between the electrodes is filled by insulating material to the outside diameter of the electrodes. 
   
   
       11 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the first electrode axially extends in the distal direction a predetermined length over the front cylinder. 
   
   
       12 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the electrodes are formed from self-supporting metal tube portions. 
   
   
       13 . An electrode arrangement for a surgical instrument as set forth in  claim 12  characterized in that the first electrode is arranged between the front cylinder and an insulating tubular first carrier, the second electrode is arranged between the first carrier and an insulating tubular second carrier, and that the electrodes rest with their end portions on the front cylinder, and the first and second carriers. 
   
   
       14 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the first electrode extends between the front cylinder and the insulating tubular carrier and the second electrode extends from the carrier to the proximal end portion, and that the electrodes bear with their end portions on the front cylinder and the carrier. 
   
   
       15 . An electrode arrangement for a surgical instrument as set forth in  claim 14  characterized in that the second electrode is proximally covered over a predetermined axial length with an insulating layer. 
   
   
       16 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized by a flushing tube within the hollow duct, which extends from the proximal end of the instrument to the front cylinder and discharges fluid at its distal end into the hollow duct in which the fluid flows back to the proximal end of the instrument. 
   
   
       17 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the end portions of the electrodes which overlap the front cylinder and the carrier or carriers are covered on their outer periphery by an insulating layer. 
   
   
       18 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the tip of the front cylinder is of a conical or wedge-shaped or rounded-off configuration. 
   
   
       19 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized by a self-supporting metal tube between the front cylinder and the carrier, with distal tube portion and a proximal tube portion, a cylindrical insulating layer on the proximal tube portion and a cylindrical metal layer at the proximal end of the insulating layer, wherein the distal tube portion forms the first electrode and the proximal metal layer forms the second electrode. 
   
   
       20 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized by a self-supporting metal tube between the front cylinder and the carrier, with a distal tube portion and a proximal tube portion, a cylindrical insulating layer on the distal tube portion and a cylindrical metal layer at the distal end of the insulating layer, wherein the distal metal layer forms the first electrode and the proximal tube portion forms the second electrode. 
   
   
       21 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the carrier has a hollow duct which goes into the hollow duct of the metal tube or the tube portions, and that the connecting lines for the electrodes are passed through the hollow duct of the carrier to the proximal end of the instrument. 
   
   
       22 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that passing through the hollow duct of the carrier and the metal tube or the tube portions in the longitudinal direction is a flushing tube extending to the front cylinder, through which flushing tube fluid is discharged at the distal end into the hollow duct, which outside the flushing tube in contact with the metal tube flows back through the hollow duct of the tube and the hollow duct of the carrier to the proximal end of the instrument. 
   
   
       23 . An electrode arrangement for a surgical instrument as set forth in  claim 19  characterized by an insulating inner tube in the hollow duct of the carrier and the metal tube, through which a connecting line for the electrode at the distal end of the tube is passed. 
   
   
       24 . An electrode arrangement for a surgical instrument as set forth in  claim 19  characterized in that the front cylinder comprises insulating material. 
   
   
       25 . An electrode arrangement for a surgical instrument as set forth in  claim 19  characterized in that the metal tube comprises aluminum or titanium and that the insulating layer is formed from the metal tube of aluminum oxide or titanium oxide. 
   
   
       26 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the axial length of the electrodes is greater than the diameter of the electrodes. 
   
   
       27 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the axial length of the electrodes is greater than the axial length of the lengthwise portion occupied by the insulator element. 
   
   
       28 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the axial length of the electrodes is greater than the outside diameter of the front cylinder or the outer conductor respectively. 
   
   
       29 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the axial spacing of the electrodes from each other is approximately equal to or smaller than the outside diameter of the front cylinder. 
   
   
       30 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that the self-supporting metal tube or tube portions and/or the metal cylinder body which are provided to form the electrodes comprise titanium or aluminum and that the insulating layers, which are provided on the metal tube or the metal tube portions are applied by anodic oxidation of the metal surface in an electrolyte bath. 
   
   
       31 . An electrode arrangement for a surgical instrument as set forth in  claim 1  characterized in that at least one of the connecting lines for connection of the electrodes has at one end a portion of spring metal which is clamped radially outwardly in the hollow duct against the inside surfaces of the electrodes. 
   
   
       32 . An electrode arrangement for a surgical instrument as set forth in  claim 31  characterized in that the spring metal portion of the connecting line or lines is wound to form a coil spring which in the hollow duct bears in self-clamping relationship with the application of the radial forces in an outward direction against the inside surface of the electrodes.