Ultrasound-assisted spinal anesthesia: A randomized comparison between midline and paramedian approaches

Abstract

Study objective: Neuraxial ultrasonography can improve the technical performance of spinal anesthesia. However, there are no data regarding the optimal approach for ultrasound-assisted spinal anesthesia. This study aimed to compare the midline and paramedian approaches for ultrasound-assisted spinal anesthesia in adult orthopedic patients.Design: A single-center, prospective, randomized controlled trial. Setting: Operating room.Patients: One hundred and twelve patients undergoing orthopedic surgery were included. Interventions: Patients were randomized to undergo either the midline or paramedian approach for preprocedural ultrasound-assisted spinal anesthesia.Measurements: The primary outcome was the number of needle passes required for successful dural puncture. Secondary outcomes were the number of needle insertions, first pass/attempt success rate, procedural time, and the incidence of periprocedural complications.Main results: The median number of needle passes was significantly lower in the paramedian group (1 [IQR, 1-2]) than in the midline group (3 [2-6]; P < 0.001). The paramedian approach showed higher first pass/attempt success rates compared with the midline group (58.9% vs. 21.4%; 91.1% vs. 53.6%; both, P < 0.001). Total procedure times were significantly shorter in the paramedian group than in the midline group (113 [72.5-146.5] vs. 196 [138-298.5] seconds; P < 0.001). The quality of sonographic images was graded as good in 94.6% of paramedian sagittal oblique views and 54.5% of transverse median views. No significant intergroup differences were found in the incidence of periprocedural complications.Conclusions: Compared with the midline approach, the ultrasound-assisted paramedian approach showed improved efficacy in terms of the number of needle manipulations, first pass success rates, and procedural time. These results suggest that the paramedian approach may be more efficient for preprocedural ultrasound-assisted spinal anesthesia. Trial registration number: NCT03491943