A surgical retractor system includes a substantially tubular retractor having several segments which can be irreversibly severed from one another to carry out a length adaptation of the retractor. A segment is subdivided into an expanding section and a plate section of differing radial flexibility and connected to each other in a one-piece material bond to allow plastic radial expansion of the retractor. An extractor can be operated to bring about plastic radial constriction of the retractor contrary to the radial expansion of the retractor. The extractor is prepared to cooperate with the plate section to bring about radial constriction of the retractor. A surgical instrument for removing a distractor or retractor from an opening includes at least one handle section defining a handle's longitudinal axis and at least one operating section defining a longitudinal effective axis, which are coupled to each other by a connecting section.
