An observational study in Spinal Anesthesia Evaluation and Lumbar Vertebrae, sponsored by Kangbuk Samsung Hospital. Not yet recruiting at 2 sites in South Korea. Open to participants aged 18 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-02-09.
Sponsored by Kangbuk Samsung Hospital · Observational
Tuffier's line is commonly used as a landmark for estimating lumbar vertebral levels during spinal anesthesia. However, its accuracy can vary depending on factors such as age, sex, BMI, and posture. This study evaluates the consistency of an alternative landmark, the "ASIS line" (a line connecting both Anterior Superior Iliac Spines), for identifying lumbar levels in the lateral decubitus position. Researchers will mark both the ASIS line and Tuffier's line on participants and use ultrasound to verify the exact vertebral level where each line crosses the spine. The goal is to determine if the ASIS line provides a more consistent and reliable estimation of lumbar levels compared to Tuffier's line.
Patients visiting the study centers (Kangbuk Samsung Hospital or St. Vincent's Hospital) who are scheduled for spinal anesthesia or lumbar ultrasound.
Exclusion Criteria:
Adult patients (aged 18-85) scheduled for spinal anesthesia or lumbar ultrasound
Diagnostic Test: Lumbar Ultrasound & Palpation
Identification of vertebral levels using Tuffier's line (palpation) and ASIS line, followed by ultrasound verification.
Consistency of Vertebral Level Identification (Standard Deviation)
The specific vertebral level where the ASIS line and Tuffier's line intersect the spine will be identified using ultrasound. The lumbar spine (from L2 upper to S1 upper) is divided into segments (e.g., L2=2, L3=3, L4=4, L5=5, S1=6). The consistency of each method is evaluated by calculating and comparing the standard deviation (SD) of the identified vertebral levels.
Time frame: Day 1 (Immediately during the ultrasound examination)
Difference in Mean Intersection Level
Comparison of the mean vertebral levels identified by the ASIS line versus Tuffier's line to determine if there is a significant difference in the average level indicated.
Time frame: Day 1
Rate of Identification within L4-L5 Interspace
The percentage of cases where the identified line falls within the target L4-L5 interspace (or within ±1 interspace range).
Time frame: Day 1
Plan to share: No
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This study is not yet recruiting, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Kangbuk Samsung Hospital