Abstract: The present invention is directed to an attachment tool (10) for use with an endoscopic instrument (30). Instrument (30) includes a working element (74) having a mechanism (28) for clamping an accessory such as tool (10). Tool (10) includes a hollow needle (12) attached to a hollow shaft (14). A flexible tube (16) passes through shaft (14) to provide fluid communication between a syringe mechanism and needle (12). End element (18) has portion (34) which is held by clamping mechanism (28). An electrical path is provided by wire (20) between element (18) and needle (12) whereby tool (10) may function not only as an injection needle but as a needle electrode.