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.

Background: Vitamin D deficiency is now a major global health problem. The prevalence of vitamin D deficiency in Indonesia is 60–90% in various studies. Age, race, sunscreen use, medication, and malabsorption diseases are all factors that affect vitamin D levels. Recent studies also show the relation between COVID-19 and vitamin D deficiency in severity and disease mortality. Vitamin D deficiency causes skeletal and extra-skeletal consequences. With limited studies on vitamin D levels of anesthesiology residents in Indonesia, we aim to determine the average vitamin D level and the affecting factors in this population. Materials and Methods: Sixty-nine anesthesiology residents working in a tertiary care hospital were enrolled in this study. The participants were asked to complete the questionnaire, and blood samples were drawn to measure serum 25(OH)D. The factors that influence vitamin D levels were recorded for analysis. Statistical analysis was performed using SPSS version 20. Results: The mean vitamin D level in anesthesiology residents was 39.99 ng/mL. There were no significant relationships between vitamin D levels among anesthesiology residents with vitamin D consumption, high-calcium foods, frequency of exercise, history of COVID-19 infection, comorbidities, and duration of exposure to sunlight. Conclusion: Prevalence of vitamin D deficiency/insufficiency was low among anesthesiology residents. Vitamin D levels were optimal in professionals who are taking vitamin D supplements.