Dorsal column function after epidural and spinal blockade: implications for the safety of walking following low-dose regional analgesia for labour.

Walking after regional blockade for labour using low-dose combinations of bupivacaine and fentanyl is possible due to the maintenance of lower limb motor power. In order to investigate concerns that dorsal column function, important in maintaining balance, is impaired after such techniques, clinical assessment of lower limb proprioception and vibration sense was evaluated in parturients after either low-dose epidural (n = 30) or spinal blockade (n = 30) for labour analgesia and compared with spinal anaesthesia (n = 30) for elective Caesarean section using a larger total dose of local anaesthetic. Of the patients receiving low-dose regional labour analgesia 7% (n = 4) had abnormal dorsal column function compared with 97% (n = 29) receiving spinal anaesthesia for Caesarean section (p < 0.001). All patients in the Caesarean section group developed lower limb motor weakness, compared with only 10% (n = 6) in the low-dose groups (p < 0.001). There were no significant differences between the low-dose groups with respect to sensory block, motor block or dorsal column function. Overall, 90% of patients receiving low-dose bupivacaine/fentanyl regional labour analgesia had both normal lower limb motor power and dorsal column function. Assessment of these parameters is recommended before allowing patients to walk after low-dose regional techniques for labour.