Ultrasonography: usefulness in localization of the Norplant contraceptive implant system

Norplant is a levonorgestrel-containing contraceptive system that consists of six small capsules (2.4 x 34 mm), which are placed subdermally. Owing to the relative newness of this contraceptive modality, problems with removal of the Norplant implants are just beginning to be reported; these consist primarily of inability to locate and remove all six implant capsules upon discontinuation. Ultrasonographic images of 14 women with the Norplant system in place were obtained in the axial and longitudinal planes. On axial view the capsules consisted of discrete circular individual areas of high echogenicity with prominent posterior shadowing. Capsules scanned in a longitudinal plane demonstrated echogenicity of the superior and inferior capsular walls, giving a tubular appearance. It was possible to demonstrate the depth of capsule placement, spatial relation to surrounding capsules, and orientation in relation to the skin surface. Ultrasonography therefore may provide a useful, noninvasive method for localization of nonpalpable Norplant implants, thus facilitating removal.