Effect of decreasing lumbar lordosis on sensory and motor block profile in patients under spinal anesthesia

The effect of lumbar lordosis on sensory blockade is less studied. Injection of hyperbaric local anesthetics in lower intervertebral spaces can cause pooling of drug in the sacral region. Lumbar lordosis limits drug cephalad spread and sensory blockade so no appropriate sensory blockade level and thus results in intraoperative pain. Determine the effect of decreasing lumbar lordosis by hip flexion on sensory and motor blockade in patients under spinal anesthesia is the goal of this study.

In this clinical trial, after intrathecal injection of hyperbaric bupivacaine 0.5% (3 ml), patients were randomly allocated to one of two positions: hip flexion for 5 minutes then horizontal supine position (case group) and horizontal supine position without hip flexion (control group). Spinal block level was assessed by pinprick and modified Bromage scale. Maximum sensory block level (MSBL), maximum motor block level (MMBL), two segment regression time (2SEGRT), complete motor block return time (CMBRT), MSBL time, MMBL time was determined, recorded and analysed. Finally, data were analysed with T-test, Chi-square and Mann- Whiteny statistical analysis.

Mean of MSBL time, MMBL time, CMBRT was 16.5±4.6 vs 19.5±9.9, 9.1±2.9 vs 10.7±3.4, 125.7±34.2 vs 137.8±36.0 minutes in case and control groups respectively that showed significant difference (p<0.05). MSLB [median (range)] T6(T4-T10), MMBL(3 scores in both groups), mean atrial blood pressure mean, mean heart rate, recovery time and frequency of hypotension and bradycardia incidence showed no significant difference in two groups.Conclusion and

Decreasing lumbar lordosis by hip felexion could not change sensory and motor block level. MSBL, MMBL and CMBRT was reduced but 2SEGRT was similar in both groups. Hip flexion decreased the lumbar lordosis but could not prevent sacral drug pooling.