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

Abstract

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, P = 0.045 and groups P and M, P = 0.004). The patients’ satisfaction score was comparable. 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.