Surgical instrument set comprises a tissue-protecting sleeve and a tool (6) having a guide section (8) fitting the inner diameter of the tissue-protecting sleeve. The diameter of the guide section is greater than the diameter of the tool element (7) of the tool. Preferred Features: The guide section of the tool has a length-measuring scale (10). The tool is a threaded drill or a screwdriver. The tissue-protecting sleeve forms part of a trocar with a sharp mandrin. The front end of the tissue-protecting sleeve has teeth.
