Comparison of landmark versus pre-procedural ultrasonography-assisted midline approach for identification of subarachnoid space in elective caesarean section: A randomised controlled trial

Background and Aims: Identification of subarachnoid space in pregnant patients can pose a great challenge to anaesthesiologists. This study was designed to compare conventional landmark technique with pre-procedural ultrasonography-assisted midline approach for identification of the subarachnoid space in elective caesarean section. Methods: After institute ethics committee approval and written informed consent, 100 parturients scheduled for elective caesarean section under spinal anaesthesia were included in this prospective randomised control trial and divided into Group L (n = 50) (landmark technique) and Group U (n = 50) (ultrasound-guided technique). Parameters such as time taken for the identification of the interspace, distance between skin and dura mater, number of insertion attempts (the primary outcome), number of passes and time taken were recorded in both the groups. Statistical analysis was done using SPSS software 16. Results: Demographic profiles of both groups were comparable. The number of attempts for needle insertion (1.04 ± 0.19 vs. 1.97 ± 0.77), number of passes in the same interspinous space (1.26 ± 0.44 vs. 1.90 ± 0.51) and the total time for successful lumbar puncture (31.90 ± 6.30 vs. 51.80 ± 12.28 s) were significantly less in Group U as compared to Group L, but the time of identification of interspinous space was significantly more in Group U (56.70 ± 13.08 s) as compared to Group L (47.10 ± 10.45 s). Conclusion: Pre-procedural ultrasound is a useful tool for successful lumbar puncture in parturients as it reduces the number of attempts with fewer side effects as compared to conventional landmark technique.