A prospective, randomized comparison between single- and multiple-injection techniques for ultrasound-guided...

Area of Science:

• Anesthesiology
• Regional Anesthesia
• Ultrasound-Guided Procedures

Background:

• Circumferential spread of local anesthetic may enhance peripheral nerve block efficacy.
• Evidence supporting this is limited, particularly for challenging blocks like the ultrasound-guided subgluteal sciatic nerve block.

Purpose of the Study:

• To test if multiple injections for circumferential spread improve sensory and motor block rates for ultrasound-guided subgluteal sciatic nerve blocks.
• To compare this technique against a single-injection method.

Main Methods:

• A randomized study of 90 patients undergoing knee surgery receiving ultrasound-guided subgluteal sciatic nerve block.
• Two groups: multiple injections for circumferential spread (Group M) vs. single injection (Group S) using 20 mL of 1.5% mepivacaine with epinephrine.
• Sensory and motor blockade assessed for 30 minutes post-injection.

Main Results:

• Analysis of 86 patients showed Group M took longer to perform than Group S.
• Significantly higher rates of complete sensory blockade (all sciatic components) in Group M (41.9%) vs. Group S (16.3%) at 30 minutes (P=0.018).
• Complete motor blockade was also more frequent in Group M for foot and toe extension (P=0.005 and P=0.027).

Conclusions:

• Multiple injections creating circumferential spread enhance sensory and motor block rates for ultrasound-guided subgluteal sciatic nerve blocks.
• This technique offers improved efficacy compared to a single-injection approach.