evidence:  Time to S1 regression was 130 ± 46 min (Group C), 144 ± 51.3 min (Group B) and 164 ± 55.99 min (Group D), P = 0.117
intervention: buprenorphine (60 μg) or dexmedetomidine (5 μg)
comparator: Sterile water (0.2 mL)
outcome: Time to complete motor recovery