Sonographic localization of an intramurally placed intratubal device--the P-block

Hysteroscopical application of hydrogelic non-medicated occlusive devices, P-blocks, in the intramural part of the human fallopian tube has become an alternative to abdominal sterilization. The check-up procedure involved repeated hysteroscopies at certain intervals. These check-ups had to be confined to the early proliferative phase of the menstrual cycle in order to get maximum vision. In view of this and as the number of patients increased, practical and administrative problems arose. The need for other methods to check the P-blocks in situ after the first insertion and later became very urgent. Linear-array ultrasound and hysterosalpingography were tried, both methods failing to reveal the exact intramural position of the P-blocks. Finally, transabdominal scanning by use of modern sonographic equipment (phase array electronic sector system) made it possible to detect the exact position of the P-blocks. Furthermore, transvaginal examination appeared to have a very high sensitivity as well as specificity even in cases with sharply retroflected uteri. Our achievements in the field of sonographic examination of intratubal devices are presented.