Comparative evaluation of three techniques for paramedian subarachnoid block: Point-of-care preprocedural ultrasound assisted, real-time ultrasound guided and landmark based.

Background and Aims: Preprocedural ultrasound (US) assisted and real-time US-guided subarachnoid block (SAB) are useful adjuncts for successful SAB. This study compared the feasibility and efficacy of real-time US-guided SAB with preprocedural US-assisted and landmark-based SAB using paramedian approach. Methods: The study enroled 150 American Society of Anesthesiologists I and II patients, aged 20-65 years, scheduled for lower limb orthopaedic surgery under SAB. In group L (n = 50), the patients underwent landmark-guided SAB utilising paramedian approach. In group P (n = 50), preprocedural US-assisted SAB was instituted and in group M (n = 50) real-time US-guided SAB was administered. The number of needle attempts for a successful SAB was the primary outcome. The secondary outcomes included successful SAB in first attempt, time taken to perform SAB and patients' satisfaction. Results: The number of attempts for SAB were (mean ± standard deviation = 1.05 ± 0.35, 1.00 ± 0.28, 1.03 ± 0.26) in groups L, P and M, respectively (P = 0.436). The SAB was successful in the first attempt in 82%, 82% and 80% in groups L, P and M, respectively (P = 0.207). The time taken for the successful SAB was more in group M as compared to groups L and P (groups L and M, Conclusion: Real-time US guidance for spinal anaesthesia resulted in needle attempts comparable to landmark and preprocedural US-assisted SAB in patients with a normal spine. The time required for the completion of the block was more in real-time US-guided SAB.