Abstract: The device comprises an endoscope shaft through which extends a working channel ending at an outlet side of the shaft. A guiding element extends through the working channel, said guiding element being preferably guided in longitudinal direction in and along the working channel. The device is set up in such a manner that the distal end section of an instrument extending in longitudinal direction next to the shaft can be moved alongside the shaft beyond the outlet side in order to move the working section of the instrument away from the outlet side so as to lengthen the distal end section of the device. The instrument is coupled to the guiding element in order to guide the working section of the instrument in a transverse direction away from the outlet side in a region opposite the outlet side in order to work in the region with the instrument.

Abstract: An instrument for large-area ablation of the mucosa including at least one first gas supply line and at least one second gas supply line whose distal ends are arranged to form an acute angle (?), so that the ends diverge distally. A free space between the distal ends of the gas supply lines allows the user to view the tissue region behind the distal end of the instrument. Due to the acute angle (?), electrodes arranged at least partially in the ends of the gas supply lines generate a wide plasma beam with which the mucosa ablation can be performed. The instrument can be guided precisely due to the view through the free space. A connecting element according to the invention is provided for attaching the ends of the gas supply lines.

Abstract: An instrument for large-area ablation of the mucosa including at least one first gas supply line and at least one second gas supply line whose distal ends are arranged to form an acute angle (?), so that the ends diverge distally. A free space between the distal ends of the gas supply lines allows the user to view the tissue region behind the distal end of the instrument. Due to the acute angle (?), electrodes arranged at least partially in the ends of the gas supply lines generate a wide plasma beam with which the mucosa ablation can be performed. The instrument can be guided precisely due to the view through the free space. A connecting element according to the invention is provided for attaching the ends of the gas supply lines.

Abstract: The device comprises an endoscope shaft through which extends a working channel ending at an outlet side of the shaft. A guiding element extends through the working channel, said guiding element being preferably guided in longitudinal direction in and along the working channel. The device is set up in such a manner that the distal end section of an instrument extending in longitudinal direction next to the shaft can be moved alongside the shaft beyond the outlet side in order to move the working section of the instrument away from the outlet side so as to lengthen the distal end section of the device. The instrument is coupled to the guiding element in order to guide the working section of the instrument in a transverse direction away from the outlet side in a region opposite the outlet side in order to work in the region with the instrument.

Abstract: An instrument for electrosurgical treatment including an instrument head which forms a conveying body with a gas-fillable lumen. The lumen is connected to at least one first opening and at least one second opening in the instrument head. A primary stream of gas leaves through the first opening. The second opening is arranged such that a secondary stream exits the second opening next to the primary stream and/or with additional secondary streams out of additional second openings—away from the instrument head, at least partially peripherally surrounding the primary stream. An electrode is located in the flow of gas exiting out of the first opening for igniting a plasma between the first opening and the tissue to be treated. Due to the secondary stream accompanying the primary stream, an ignition of the plasma is successful even if the instrument is at a relatively large distance from the tissue.