Comparison between two anatomic landmarks using ultrasonography in spinal anesthesia: a randomized controlled trial

Background and objective: Tuffier's line is the most used anatomic landmark in clinical practice. We aimed to compare the accuracy of Tuffier's line with a landmark that joins the two lowest points of the tenth rib on the flanks with the help of ultrasound.Methods: A prospective, randomized, controlled, double-blinded trial was performed with 200 patients aged between 18 and 50. Patients taller than 180cm or shorter than 150cm, or with body mass index >30kg/m(2) were excluded. The first anesthesiologist examined Group T according to Tuffier's line and Group R according to the tenth rib line and marked L4-5. Only one anesthesiologist evaluated the marked level with ultrasound for accuracy of the anesthesiologist's examination.Results: There was no difference between groups for demographic and surgical data (p>0.05). However, we observed a significant difference between the two techniques for success rate (60% in group T vs. 74% in group R) at estimation of correct level (p<0.05). There was no correlation between success of estimation and patients' demographic data.Conclusion: We conclude that the tenth rib line is better than Tuffier's line for accuracy with palpation. However, it must be confirmed by further studies including more than one examiner for palpation and also include different patient populations.