Ultrasound-guided sciatic nerve block in infants and toddlers produces successful anesthesia regardless of the motor response

Abstract

The primary objective of this study was to assess the success rate of ultrasound-guided sciatic needle placement regardless of the motor stimulation in infants and toddlers. Forty-five consecutive patients aged 7 months-2 years, scheduled for foot surgery, were included in this prospective, descriptive and blinded study. After induction of general anesthesia, sciatic nerve block was performed under ultrasound guidance in the subgluteal area using an insulated needle connected to a nerve stimulator, with the power off. At the precise point when it was presumed that the needle was touching the sciatic nerve, the peripheral nerve stimulator was turned on at 0.5 mA and the current was slowly decreased to 0.2 mA. Presence and location of any motor responses were observed and recorded. Statistical analysis was applied to compare the success rate in patients who did and did not exhibit a motor response to electrical stimulation. Postoperatively, block duration and analgesic consumption were recorded. The sciatic nerve could be distinctly visualized in 44 children, and all these blocks were successful. Only 22% patients showed any motor response to electrical stimulation. There was no significant difference in block characteristics between patients who exhibited a motor response with electrical stimulation and those who did not. Success rate of ultrasound-guided sciatic nerve block remains unaltered irrespective of motor response to neurostimulation.