Korean J Pain.  2007 Jun;20(1):40-45. 10.3344/kjp.2007.20.1.40.

The Success Rate of Caudal Block Under Ultrasound Guidance and the Direction of the Needle in the Sacral Canal

• Roh JH
• Kim WO
• Yoon KB
• Yoon DM

• KMID: 2278038
• DOI: http://doi.org/10.3344/kjp.2007.20.1.40

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.

Keyword

caudal block; direction of needle; sacral hiatus; success rate; ultrasound guidance

MeSH Terms

Anesthesia
Chronic Pain
Ethics Committees
Fluoroscopy
Humans
Ligaments
Needles*
Nerve Block
Ultrasonography*