Correlation Between Skin-to-Subarachnoid Space Depth in the Lumbar Region Measured by Ultrasound and Needle Insertion...

Background and aim Lumbar puncture and spinal anesthesia are critical procedures in medical practice, requiring precise needle placement to access the subarachnoid space. This study aimed to assess the correlation between ultrasound (USG) measurements of skin-to-subarachnoid space depth (SSD) and actual needle insertion depth. Methods The study received ethical approval from the institutional review board. Informed consent was obtained from all participants. This prospective observational study was conducted in a tertiary care hospital, involving 100 adult patients undergoing spinal anesthesia. USG measurements of SSD were taken, and actual needle insertion depths were recorded. Statistical analysis included Pearson correlation coefficients, independent t-tests, and one-way ANOVA, with a significance level set at p < 0.05. Results The mean SSD measured by USG was 4.51 cm (SD = 0.62), while the actual needle insertion depth was 4.57 cm (SD = 0.62). A strong positive correlation was found between USG measurements and actual needle depth (r = 0.94, p < 0.001). Stocker's formula showed a correlation coefficient of r = 0.86 (p < 0.001). Conclusions USG guidance significantly improves the accuracy of SSD measurements compared to traditional methods, including Stocker's formula, thereby enhancing the safety and efficacy of lumbar puncture procedures.