THE PARASACRAL SCIATIC-NERVE BLOCK

Background and Objectives. The clinical utility of a new parasacral ap proach for conduction block of the sciatic nerve was investigated, wit h critical examination of onset, extent, and success rates when this b lock was used for surgical procedures below the knee. Methods. Thirty ASA I-m patients presenting for surgery on the lower limb were enrolle d. All received 30 mt of 1.5% lidocaine with 1:200,000 epinephrine fol lowing nerve stimulator identification of the sciatic nerve at less th an or equal to 0.2 mA or less. Trans-sartorial saphenous nerve blocks were performed to provide anesthesia to the medial leg. Results. Overa ll success for surgical anesthesia with this block was 97%. All compon ents of the sacral plexus could be blocked with this approach, and 93% of patients displayed evidence of obturator nerve motor block. Howeve r, no patient displayed evidence of obturator sensory anesthesia that could be mapped. Saphenous nerve blocks were 100% effective in providi ng surgical anesthesia for the procedures performed. Conclusions: The parasacral approach to the sciatic nerve exhibits a high success rate, resulting in anesthesia of the entire sacral plexus and generally in motor block of the obturator nerve was an interesting observation.