Real-time ultrasound-guided spinal anesthesia in patients with predicted difficult anatomy

BACKGROUND: There are limited reports of lumbar neuraxial blocks using real-time US in patients with predicted difficulties. We compared the number of attempts to perform spinal anesthesia using real-time US guidance versus landmark technique in patients meeting predefined criteria for difficult spinal anesthesia. We also compared procedure time, block success, patient satisfaction and difficulty scores between groups. METHODS: Following institutional review board approval patients scheduled for total hip or knee arthroplasty with expected difficulty to perform spinal anesthesia were included. Number of attempts, block time, success rate, patient satisfaction and difficulty scores were recorded and we conducted the Kruskal-Wallis non-parametric test of difference between the groups. RESULTS : Thirty-eight patients were enrolled and a total of 32 data sets was analyzed. For number of attempts, we observed no difference between the groups (P<0.83). The US group resulted in marginally higher time to block compared to the control (P<0.0653). The US group resulted in marginally higher satisfaction compared to the control group (P<0.09). The block success rate was 100% in both groups. Anesthesiologists rated the US group procedure more difficult than the control group (χ²=10.85, P<0.0010). CONCLUSIONS: This trial suggests that real-time US guidance for spinal anesthesia in challenging patients in comparison to the controlled group was completed in longer time, with lower needle insertion attempts, and higher patient satisfaction scores but without statistically significant differences.