[Roentgen studies (lateral distance image) for precise determination of tumors of the rectum].

The lateral distant view (LDV) of the rectum is proposed for more precise identification of localization of rectal tumors for preoperative planning and to increase the number of sphincter saving operations. In a prospective study 129 patients with rectal tumors were compared with radiologic and rectoscopic measurements and with the intraoperative tumor site. Other factors which may influence the resectability of tumors have been examined in a part of this patients by measuring the width of the presacral space, the anorectal angle and the pelvic diameters by radiological pelvimetry. Radiological measurement on the lateral distant view showed that tumors usually are located much higher (0.5 to 12.5 cm) than is suggested by rectoscopy. Unlike the rectoscopy, the lateral distant view also can be used for measuring the length of the anal canal. This measurement is most important for evaluating the distance between the tumor and the inner end of the anal canal and reflects the width of a possibly tumor-free margin. Sphincter saving operations could be predicted much better by the lateral distant view than by rectoscopy.