초음파 영상의 유도를 이용한 미추경막외블록의 성공률과천골관 내에서의 바늘의 방향

Abstract

Background Caudal block is useful when anesthesia for surgery or treatment for chronic pain is needed, but this procedure has a failure rate of up to 25% even when it performed byan experienced physician. This high failure rate is usually due to improper needle placement.

Methods After gaining approval of the ethics committee, 46 patients received caudal blocks under ultrasound guidance; these were performed after the anatomical structures in the sacral hiatus had been measured with ultrasound. All these procedures were performed by the same anesthesiologist. The position and direction of the needle were identified using fluoroscopy by injecting a radio-opaque contrast through the needle. The time taken from thelidocaine injection to verification of the needle was measured and the planned nerve block was then carried out.

Results All cases of needle insertion into the sacral canal under ultrasound guidance were successful. The average duration of the procedure and the trial count were 134.1 ± 10.1 seconds and 1.2 ± 0.1, respectively. In 12 of the 46 cases (26%), the needle deviated either left or right in the sacral canal, so the direction of the needle had to be adjusted. The distance between two cornua, the depth of the sacral hiatus and the thickness and length of the sacrococcygeal ligament were 17.1 ± 0.4, 3.9 ± 0.3, 2.3 ± 0.1 and 24.9 ± 0.9 mm, respectively.

Conclusions Ultrasound guidance can increase the success rate of inserting a needle into the sacral canal. However, even when ultrasound is used, the needle can deviate either left or right in the sacral canal.