Extent and duration of isobaric 0.5% bupivacaine spinal anesthesia by using new open-end pencil point spinal needle

Extent and duration of isobaric 0.5% bupivacaine spinal anesthesia by using two spinal needles; a new 25 gauge open-end pencil point spinal needle (needle tip is open as a hole after pulling out the stylet, Doctor Japan Co., Japan) and a 25 gauge Quincke needle (TOP Co., Japan) were studied clinically in 24 patients for elective lower extremity surgery. Patients were randomly assigned into two groups of 12 patients each according to the spinal needle used. Lumbar puncture was performed between L3-4 with the patient in lateral decubitus position. After isobaric 0.5% bupivacaine 4.0 ml was injected in 20 seconds, the patient was placed in supine position, and the onset of anesthesia was assessed by loss of cold sensation (alcohol sponge), sensory block (pinprick) and motor block (modified Bromage's scale) in every 5 minutes until 30 minutes. Recovery of motor block and adverse effects were assessed by a blinded observer. Sensory block at 30 minutes by Quincke needle was Th 8.4 +/- 1.0 and by new open-end pencil point needle it was Th 8.5 +/- 3.2 dermatomes. Two groups did not differ significantly in sensory block and also in motor block. No adverse effect was observed in both groups. These results indicate that this new open-end pencil point spinal needle is very useful for preventing adverse effects of spinal anesthesia.