Abstract: Objective To evaluate the anesthesia effect of ultrasound-guided single shot spinal anesthesia at L5-S1 and L4-5 intervertebral space in transurethral ureteroscopic lithotripsy.
Methods Forty patients who were scheduled for transurethral ureteroscopic lithotripsy were enrolled in this study.The patients allocated randomly into two parallel groups(20 patients for each),namely L5-S1(Group A) and L4-5(Group B).Forty patients underwent real-time ultrasound-guided spinal anesthesia,When the puncture is successful,10 to 17 mg of 0.5% bupivacaine was injected.The hemodynamic parameters,total duration of surgery,anesthesia effect,anesthesia satisfaction,total bupivacaine used,total blocked segments,sedative analgesics and vasoactive drugs used were recorded.
Results The vital signs were stable during the operation.There was no significant difference in heart rate(P>0.05),systolic blood pressure and diastolic blood pressure between the two groups at each time measured.The satisfaction rate of anesthesia in both group A and group B was 100%.None of the patients transferred to general anesthesia due to pain or insufficient block.One patient in group B needed vasoactive drugs to maintain hemodynamic stability.There was no statistical significance in the dose of bupivacaine used in group A and group B(P>0.05),but the total blocked segments in group A was less than that in group B with the equal bupivacaine dosage[Group A was (14±2),Group B was (15±2),P<0.05].
Conclusion Real-time ultrasound-guided spinal anesthesia at L5-S1 and L4-5 intervertebral space are feasible and can be safely used for patients underwent transurethral ureteroscopic lithotripsy.With the same dose of bupivacaine,spinal anesthesia by L5-S1 approach produced less blocked segments than L4-5 approach.

Key words: lumbar anesthesia, ultrasonic guidance, transurethral ureteroscopic lithotripsy, bupivacaine