METHODS: Consenting parturients admitted to our obstetric suite for spontaneous or induced labor were randomized to receive epidural analgesia using either the ALOR or SLOR technique. Our primary outcome was to compare the impact of the SLOR and ALOR technique on pain score improvement measured 30 minutes after administration of epidural block. Our secondary outcomes included the density of motor blockade and analgesic efficacy measured at 30 minutes. Primary and secondary outcomes were compared using the Student t test and Mann-Whitney U test. Statistical significance was set at P < .017 for primary and secondary outcomes, considering Bonferroni correction for multiple comparisons. Other comparisons were considered exploratory.
RESULTS: Four hundred parturients were included; 24 were excluded from the final analysis. After 30 minutes, pain score reduction (ALOR, 4.7 ± 2.9/10; SLOR, 4.9 ± 3.0/10; P = .49), motor block (ALOR, 1.4 ± 0.8; SLOR, 1.3 ± 0.8; P = .27), and efficacy of the block (ALOR, 1.0 ± 0.7; SLOR, 1.0 ± 0.6; P = .87) did not differ significantly between groups.
CONCLUSIONS: Pain score reduction after 30 minutes and onset of the block were not affected by the technique used to locate the epidural space.