Sensory levels of study participants were measured by pinprick test.The duration of sensory blockade was recorded from initial sensory block occurrence to recovery at L2 level.

• 研究中感觉阻滞平面测量采用传统的针刺法，记录每组感觉神经阻滞持续时间（从注药后阻滞平面出现到感觉恢复到L2水平）。