The feasibility of color Doppler ultrasonography for caudal epidural steroid injection

Although it entails a radiation hazard risk, the use of fluoroscopy during caudal epidural steroid injection has increased to help place the medication more accurately and allowed physicians to maximize the procedure's therapeutic success rate. To investigate the feasibility of using real-time high resolution ultrasonography for guiding the epidural needle into the caudal epidural space and to confirm any vascular intake of medication, we performed color Doppler ultrasonography while medication was being injected into the caudal epidural space of 53 patients with low back pain and sciatica. We defined the injection as being successful if unidirectional flow (observed as one dominant color) of the solution was observed with color Doppler ultrasonography through the epidural space beneath the sacrococcygeal ligament, with no flows being observed in other directions (observed as multiple colors). The correct placement of the medication was then confirmed by fluoroscopy. In 52 of the 53 subjects, the medications were successfully injected into the caudal epidural space with ultrasonography assistance. In fluoroscopy, of these 52 patients, 50 revealed correct placement of the medicine into the epidural space. In conclusion, ultrasonography may be a reliable imaging modality for caudal epidural steroid injection, and its several advantages such as its convenience and the lack of a radiation hazard, make it preferable to fluoroscopy.