Paramedian Spinal Anesthesia: Landmark vs. Ultrasound-guided Approaches

Background: Multiple attempts at needle redirection for paramedian spinal anesthesia can lead to significant complications, particularly in elderly patients. We hypothesized that ultrasound guidance may reduce the need for redirection (s), the associated discomfort, and complications in conventional landmark-guided paramedian spinal anesthesia. Methods: A total of 70 patients >65 years of age, undergoing total knee or hip arthroplasty, were randomly assigned to pre-procedural ultrasound-guided paramedian (PP) or conventional surface landmark-guided paramedian (CP) approach groups. The paramedian approach was performed at L3-4 in the lateral decubitus position. Results: The median number of needle redirection attempts was significantly lower in group PP (2 (interquartile range (IQR) 1-2)) than in group CP (4 (IQR 2-8.5)) (P<0.001). The median number of needle insertion attempts was also significantly lower in group PP than in group CP (P=0.003). All patients in group PP underwent successful needle insertion at the 3-4 lumbar intrathecal space, while 7 in group CP required multiple interspinous space insertions for success (P=0.006). No patient in group PP experienced significant complications related to spinal anesthesia. However, 5 (13.9%), 1 (2.8%), and 7 patients (19.4%) in group CP experienced transient radicular pain, paresthesia, and traumatic puncture, respectively. Conclusion: Application of pre-procedural ultrasound guidance in paramedian spinal anesthesia in elderly patients resulted in a significant decrease in the number of needle redirection and insertion attempts, as well as a reduction in related complications compared with the conventional paramedian technique.