Relationship between age, sex, and anthropometric factors with the distance of L4-L5 interspace from Tuffier's line: Observational study with ultrasonography guidance

Background: The anatomical marker used in spinal anesthesia is L4-L5 interspace. The L4-L5 interspace is thought to be right on the Tuffier's line, which connects the two highest points on the iliac crest. The location of L4-L5 interspace from the Tuffier's line varies greatly because of the influence of several factors such as differences in race, sex, age, and anthropometric factors. This study aimed to examine the relationship between age, sex, and anthropometry factors with the distance of L4-L5 interspace from the Tuffier's line using ultrasound guidance at Cipto Mangunkusumo National General Hospital. Materials and Methods: This was an observational analytic study with a cross-sectional design in 93 subjects at Cipto Mangunkusumo National General Hospital recruited for the study. Statistical analysis was performed to find the relationship between age, sex, and anthropometry factors with the distance of L4-L5 interspace from the Tuffier's line and to continue with multivariate analysis to obtain the prediction formula of the distance between L4-L5 interspace and the Tuffier's line. Results: This study found that the distance of L4-L5 interspace to the Tuffier's line is -2.59 ± 1.58 cm. Correlation analysis showed a significant relationship between height and sex to the distance of L4-L5 interspace and the Tuffier's line. The distance prediction formula obtained in this study is 4.921 + [0.536 × (1 for male or 2 for female)] + (-0.052 × height in cm). Conclusion: There was a significant relationship between height and sex to the distance of L4-L5 interspace from the Tuffier's line.