Transient neurological symptoms after isobaric subarachnoid anesthesia with 2% lidocaine: The impact of needle type

BACKGROUND: The reported incidence of transient neurological symptoms (TNS) after subarachnoid lidocaine administration is as high as 40%. We designed this clinical trial to determine the incidence of TNS with two different pencil-point spinal needles: one-orifice (Atraucan) and two-orifice (Eldor) spinal needles. METHODS: Ninety-nine ASA physical status I or II patients undergoing surgical procedures of the urinary bladder or prostate were prospectively allocated to receive spinal anesthesia with 40 mg, 2% isobaric lidocaine plus fentanyl injected through either a 26-gauge Atraucan (n = 52) or a 26-gauge Eldor (n = 47) spinal needle. During the first three postoperative days, patients were observed for postoperative complications, including TNS. The primary end-point for this trial was the percentage of TNS in both double- and single-orifice spinal needle procedures. RESULTS: The incidence of TNS was higher when spinal anesthesia was done through the Atraucan needle (28.8% vs 8.5%, P = 0.006). Fifty percent of the patients in the double-orifice group versus 100% of the single-orifice group developed TNS after surgery in the lithotomy position (P = 0.014). The relative risk for developing TNS with the Eldor needle was 0.29 (95% CI: 0.07-0.75) compared with the Atraucan needle. CONCLUSIONS: The use of a double-orifice spinal needle was associated with a lower incidence of TNS, which may have been due to the needle design.