Continuous parasacral sciatic block: a radiographic study.

Abstract

Parasacral sciatic blockade results in anesthesia of the entire sacral plexus. In this study we sought to determine the spread of the local anesthetic injected through a parasacral catheter, the anatomical location of the inserted catheters, and the extent and reliability of the blockade. In this study, 87 consecutive patients undergoing major lower limb surgery were enrolled. After placement of the catheter and injection of 8 mL of radio-opaque contrast dye, radiographic images were evaluated for dispersion of the injectate. Sensory and motor evaluations were also performed. Radiographic analysis of the injectates revealed that nearly all catheters (86 catheters, 99%) were in the correct anatomical position. The mean volume of local anesthetic injection was 21 +/- 3 mL. All patients developed a full sensory block of all three major components of the sciatic plexus (tibial, common peroneal, and posterior cutaneous nerve of the thigh). We conclude that the parasacral sciatic block results in frequent success of blockade of all three major components of the sciatic plexus and it has a small risk of complications. Contrast radiography can be used to document the catheter placement. The parasacral sciatic block results in a frequent success rate of blockade of all three major components of the sciatic plexus (tibial, common peroneal, and cutaneous nerve of thigh). A contrast radiography can be used to confirm the proper position of the catheter.