Transgluteal sonography. A new approach to the posterior pelvic compartment.

Ten patients with presacral tumors proved by histologic and computed-tomographic investigations underwent ultrasound scanning. The sound beam was directed through the ischial foramen along longitudinal, transverse, and oblique planes. Nine of 10 tumors localized in the sacral fossa were identified sonographically. In six of 10 instances, tumor demarcation was possible. Sonographic evaluation was impaired because of distance between the transducer and the target due to a patient's large volume and by the cranial location of the tumor. The transgluteal approach is suggested for sonographically guided percutaneous biopsy.