Vertebral level of tuffier's line measured by ultrasonography in parturients in the lateral decubitus position

Tuffier's line intersects the spine at the L4 spinous process or at the L4-L5 intervertebral space. Full-term parturient women undergo various physical changes. Therefore, determining the vertebral level with Tuffier's line based on palpation inevitably is not very accurate. This study aimed to use ultrasound to verify the difference between vertebral levels for the palpated Tuffier's line in parturient and non-parturient women in the lateral decubitus position. In this study, consecutively enrolled 20 parturient women at 27-35 weeks of gestation and 20 non-parturient women scheduled for regional anesthesia. In the left lateral position, the location of the vertebra was identified using ultrasonography. We marked every intervertebral space from L5 to L2 vertebra, divided each spinous process into two equal parts, and numbered the spaces sequentially from 1 to 9. A Tuffier's line was drawn by palpating, recorded the vertebral level that this line intersected. The mean value of an arbitrary number of vertebral level of Tuffier's line was 5.4 ± 0.9 in the non-pregnant group and this represents L4-lower vertebral level. In the pregnant group, the mean value was 2.0 ± 1.0 which represents L3-lower vertebral level. There was a significant difference between the two groups (P < 0.05)