Abstract: An endoscopic surgical instrument for removing tissue or bone, or for electrosurgical purposes. The instrument comprises a distal end member containing a cutting device, a proximal member, and between the distal member and the proximal member a hollow, generally tubular intermediate member which deforms elastically when the angle between the distal member and the proximal member is changed. The intermediate member can for example be composed of a nickel titanium alloy, and/or can be slotted, and/or can be in the form of an accordion, and/or be in the form of a coil. The instrument can include a cutting device which is housed in the distal end member and part of which protrudes beyond the window in the distal member, and a means for operating the cutting device. Alternatively, the instrument can include electrical components which deliver and electrosurgical treatment through the window.