Impact of Age, Sex and Body Mass Index on Anatomical Variations of the Femoral Nerve in Relation to the Femoral Artery: Implications for Ultrasound-Guided Femoral Nerve Blocks - An observational study.

ABSTRACT: Background: Ultrasound-guided femoral nerve block is a commonly used technique for regional anesthesia. However, variations in the anatomical relationship between the femoral nerve and artery can complicate accurate nerve identification during the procedure. This study aimed to explore whether age, sex, or BMI influence the anatomical variation of the femoral nerve concerning the femoral artery. Methods: Conducted at a tertiary care emergency and trauma center from, this study enrolled 200 consecutive patients scheduled for femoral fracture fixation. After excluding five patients due to poor image quality, the final cohort comprised 195 individuals, with 128 males and 68 females. Ultrasound imaging was employed to measure the femoral nerve-artery (FN-FA) distance at the inguinal crease level with patients in the supine position. Subsequent data analysis examined correlations with age, sex, and BMI. Results: The findings revealed that age and sex significantly influenced the femoral nerve's position relative to the artery. Older patients tended to exhibit a greater distance between the nerve and artery, while males showed a closer proximity between the nerve and artery compared to females. Interestingly, BMI did not demonstrate a noticeable impact on this relationship. Conclusion: This study suggests that age-related changes in muscle and fascia, such as sarcopenia and variations in fascial thickness and elasticity, might contribute to the observed variations in nerve location. Understanding these factors holds promise for refining the accuracy and safety of ultrasound-guided femoral nerve blocks. The significance of tailoring approaches based on individual patient characteristics is underscored, potentially enhancing the procedure's precision and safety.Top of Form Keywords:Bottom of Form Ultrasound guided regional block; Femoral nerve block; Regional anesthesia; Femoral nerve; Femoral artery; Sarcopenia.