The Effectiveness of Ultrasound Guidance in Caudal Epidural Block

ABSTRACT

STUDY DESIGN: A prospective study. OBJECTIVES: To evaluate the effectiveness of ultrasound guidance in caudal epidural block and sonographic feature of sacral hiatus. SUMMARY OF LITERATURE REVIEW High success rate of ultrasound-guided regional nerve block has been reported and recently, ultrasound-guided nerve block in spinal field has been introduced. MATERIALS AND METHODS: Ultrasound-guided caudal epidural block was performed in 48 patients with radiating pain to leg. Patient was placed in the prone position and sonographic image of sacral hiatus was obtained using linear probe. After measuring the intercornual distance, thickness of sacrococcygeal membrane and depth of sacral canal in transverse view, then the probe was rotated 90degrees to obtain the longitudinal view of the sacral hiatus. Under ultrasound guidance, a 21-gauge needle was inserted into the sacral hiatus in parallel with sacrum base. After contrast dye injection, needle placement was checked by the fluoroscopy and then medication was injected into the caudal epidural space. We investigated the change of radiating pain after caudal epidural block using visual analogue scale(VAS). RESULTS: The intercornual distance was mean 16.4+/-2.3mm, thickness of sacrococcygeal membrane was mean 2.8+/-0.9mm and depth of sacral hiatus was mean 2.6+/-0.9mm. There was 97.9% success rate of the caudal epidural block under ultrasound guidance. The mean VAS for radiating pain was improved from 7.5+/-0.7 before the block to 2.8+/-1.5 after the block. CONCLUSIONS: Ultrasound-guided caudal epidural block seems to provide good anatomical landmark of sacral hiatus and an effective tool with high success.