Determination of Vertebral Structure using Ultrasound Examination at Manually Identified Midpoint of Intercristal Line in Pregnant Women at Term: A Cross-sectional Study

Introduction: Manual palpation has traditionally been used to locate the intercristal line and corresponding vertebral level for administering subarachnoid blocks. However, ultrasound examination provides an alternative approach for accurate vertebral identification. Aim: To determine the vertebral structure using ultrasound at the manually marked midpoint of the intercristal line in pregnant women at term. Materials and Methods: A cross-sectional study was conducted at Government Dharmapuri Medical College Hospital (GDMCH) in Dharmapuri, Tamil Nadu, India from March 20, 2023 to April 18, 2023. It involved 100 pregnant women at term. Two independent observers estimated the vertebral space at the intercristal line – one using manual palpation and the other using ultrasound guidance. The primary outcome assessed was the determination of the vertebral structure using ultrasound examination at the manually marked midpoint of the intercristal line in pregnant women at term. The secondary outcome assessed included evaluating the accuracy of manual palpation in identifying vertebral levels compared to ultrasound examination and assessing factors such as Body Mass Index (BMI) that may influence the accuracy of vertebral level identification. One-way Analysis of Variance (ANOVA) was used to compare the mean±SD of continuous variables among more than two groups. A p-value