Brief reports: a comparison of an injection cephalad or caudad to the division of the sciatic nerve for ultrasound-guided popliteal block: a prospective randomized study.

Background: The optimal site for local anesthetic injection during ultrasound-guided sciatic popliteal block remains controversial.

Methods: Patients were randomized to receive 25 mL ropivacaine 0.75% around the sciatic nerve cephalad to the peroneal-tibial division in group A (n = 51) or caudad to the division in group B (n = 51). The sensory and motor blocks were evaluated every 5 minutes up to 30 minutes.

Results: Rates of complete sensory block and surgical anesthesia were superior in group B (P < 0.0001).

Conclusion: The caudad technique provided better surgical anesthesia.