Prior to tracheal surgery, the precise diameter and extent of the resection must be clearly defined. The trachea is an organ approximately 10-12 cm in length. Therefore, resection of a very large segment may result in failure. Literature reports resection of up to half the trachea. However, the greater the amount resected, the higher the complication rate. Thus, resection of a narrower segment increases the success rate. For these reasons, precise determination of the diameter and extent of the stenotic segment preoperatively is crucial.