Flexible catheter for high-frequency therapy of biological tissue and method of using same

A method for electrosurgical treatment of body tissue in the lumen of a hollow organ, including the steps of:

• a) providing a catheter comprising:
• a flexible shaft tube of biocompatible plastic material, which defines a lumen,
• a distal end piece fixed to a distal end of the flexible shaft tube, a proximal end of the distal end piece projects into the lumen of the flexible shaft tube and there forms a clamping connection to the distal end of the flexible shaft tube, wherein the distal end piece is divided into a proximal sub-piece having at least one change in outside diameter and a distal sub-piece, wherein the proximal end of the distal end piece is part of the proximal sub-piece, and the distal sub-piece is connected to the proximal sub-piece by a distal part of the proximal sub-piece enclosing a proximal part of the distal sub-piece,
• at least one electrode on a distal portion of the flexible shaft tube adapted to deliver high-frequency alternating current to body tissue surrounding the catheter during treatment, wherein the distal portion of the flexible shaft tube comprises the distal end of the flexible shaft tube, wherein said at least one electrode includes a sleeve in the form of a hollow cylinder which exerts a radially acting clamping force on the clamping connection, and at least one electric line which is electrically conductingly connected to the at least one electrode and which extends to a proximal end of the catheter;
• b) placing a guide wire in the lumen of the hollow organ;
• c) pushing the catheter over the guide wire, while the guide wire remains in position;
• d) advancing the catheter until at the least one electrode has reached a desired position;
• and
• e) applying high-frequency AC voltage to the at least one electrode thereby delivering the high frequency alternating current to the body tissue surrounding the catheter during treatment.

A method for electrosurgical treatment of varicose veins, including the steps of:

• a) providing a catheter comprising:
• a flexible shaft tube of biocompatible plastic material, which defines a lumen,
• a distal end piece fixed to a distal end of the flexible shaft tube, a proximal end of the distal end piece projects into the lumen of the flexible shaft tube and there forms a clamping connection to the distal end of the flexible shaft tube, wherein the distal end piece is divided into a proximal sub-piece having at least one change in outside diameter and a distal sub-piece, wherein the proximal end of the distal end piece is part of the proximal sub-piece, and the distal sub-piece is connected to the proximal sub-piece by a distal part of the proximal sub-piece enclosing a proximal part of the distal sub-piece,
• at least one electrode on a distal portion of the flexible shaft tube adapted to deliver high-frequency alternating current to body tissue surrounding the catheter during treatment, wherein the distal portion of the flexible shaft tube comprises the distal end of the flexible shaft tube, wherein said at least one electrode includes a sleeve in the form of a hollow cylinder which exerts a radially acting clamping force on the clamping connection, and
• at least one electric line which is electrically conductingly connected to the at least one electrode and which extends to a proximal end of the catheter;
• b) opening a desired blood vein to create an opened vein;
• c) introducing a guide wire into the opened vein;
• d) pushing the catheter over the guide wire, introducing the catheter into the opened vein and advancing the catheter as far as the end of the opened vein;
• e) providing a high-frequency AC voltage to the at least one electrode when the distal end of the catheter is correctly positioned thereby delivering the high frequency alternating current to the body tissue surrounding the catheter during treatment;
• and
• f) retracting the catheter slowly in a proximal direction relative to the guide wire or together with the guide wire with a speed that is adapted to the geometry of the opened vein being treated and to the high-frequency AC voltage.

A method for constriction or sclerosis of a fallopian tube, including the steps of:

• a) providing a catheter comprising:
• a flexible shaft tube of biocompatible plastic material, which defines a lumen,
• a distal end piece fixed to a distal end of the flexible shaft tube, a proximal end of the distal end piece projects into the lumen of the flexible shaft tube and there forms a clamping connection to the distal end of the flexible shaft tube, wherein the distal end piece is divided into a proximal sub-piece having at least one change in outside diameter and a distal sub-piece, wherein the proximal end of the distal end piece is part of the proximal sub-piece, and the distal sub-piece is connected to the proximal sub-piece by a distal part of the proximal sub-piece enclosing a proximal part of the distal sub-piece,
• at least one electrode on a distal end of the flexible shaft tube adapted to deliver high-frequency alternating current to body tissue surrounding the catheter during treatment, wherein the distal portion of the flexible shaft tube comprises the distal end of the flexible shaft tube, wherein said at least one electrode includes a sleeve in the form of a hollow cylinder which exerts a radially acting clamping force on the clamping connection, and
• at least one electric line which is electrically conductingly connected to the at least one electrode and which extends to a proximal end of the catheter;
• b) introducing a guide wire and thereafter the catheter by means of a hysteroscope or an endoscope from a uterus into the fallopian tube to be closed off;
• c) advancing the catheter as far as the end of the fallopian tube;
• d) providing a high-frequency AC voltage to the at least one electrode when a distal end of the catheter is correctly positioned thereby delivering the high frequency alternating current to the body tissue surrounding the catheter during treatment;
• and
• e) withdrawing the catheter while delivering a high-frequency current within a defined distance so that a desired region contracts in respect of diameter and closes as a result.

A method for treating obstructive tumors in the region of the bile duct (ductus choledochus) in a patient, including the steps of:

• a) providing a catheter comprising:
• a flexible shaft tube of biocompatible plastic material, which defines a lumen,
• a distal end piece fixed to a distal end of the flexible shaft tube, a proximal end of the distal end piece projects into the lumen of the flexible shaft tube and there forms a clamping connection to the distal end of the flexible shaft tube, wherein the distal end piece is divided into a proximal sub-piece having at least one change in outside diameter and a distal sub-piece, wherein the proximal end of the distal end piece is part of the proximal sub-piece, and the distal sub-piece is connected to the proximal sub-piece by a distal part of the proximal sub-piece enclosing a proximal part of the distal sub-piece,
• at least one electrode on a distal portion of the flexible shaft tube adapted to deliver high-frequency alternating current to body tissue surrounding the catheter during treatment, wherein the distal portion of the flexible shaft tube comprises the distal end of the flexible shaft tube, wherein said at least one electrode includes a sleeve in the form of a hollow cylinder which exerts a radially acting clamping force on the clamping connection, and
• at least one electric line which is electrically conductingly connected to the at least one electrode and which extends to a proximal end of the catheter;
• b) introducing a flexible endoscope, gastroscope or duodenoscope through the patient, and positioning a distal end of the endoscope, gastroscope or duodenoscope in front of papilla of the duodenum;
• c) introducing a guide wire into the bile duct and advancing the guide wire beyond a portion of the bile duct which is to be treated,
• d) advancing the catheter over the guide wire until the at least one electrode of the catheter is within the portion of the bile duct that is to be treated;
• and
• e) applying a high-frequency AC voltage to the at least one electrode thereby delivering the high frequency alternating current to the body tissue surrounding the catheter during treatment and thereby coagulating the body tissue surrounding the catheter during treatment.