Consistency of ASIS Line vs. Tuffier's Line for Lumbar Level Identification

NCT07396961 | Not Yet Recruiting

• 1 other identifier: 2026-01-002
• Study Type: observational
• Target: 140
• Locations: 1 country
• Sites: 2

Brief Summary

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.

Conditions

Spinal Anesthesia Evaluation; Lumbar Vertebrae

Keywords

vertebral level; Ultrasound; Tuffier's line; ASIS; Lateral decubitus position

Outcome Measures

Primary Outcomes (1)

• 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.

  Day 1 (Immediately during the ultrasound examination)

Secondary Outcomes (2)

• Difference in Mean Intersection Level

  Day 1

• Rate of Identification within L4-L5 Interspace

  Day 1

Study Arms (1)

Study Cohort

Adult patients (aged 18-85) scheduled for spinal anesthesia or lumbar ultrasound

Diagnostic Test: Lumbar Ultrasound & Palpation

Interventions

Lumbar Ultrasound & Palpation DIAGNOSTIC_TEST

Identification of vertebral levels using Tuffier's line (palpation) and ASIS line, followed by ultrasound verification.

Study Cohort

Eligibility Criteria

• Age: 18 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients visiting the study centers (Kangbuk Samsung Hospital or St. Vincent's Hospital) who are scheduled for spinal anesthesia or lumbar ultrasound.

You may qualify if:

• Adults aged 18 to 85 years
• Patients scheduled for spinal anesthesia or lumbar ultrasound
• Participants who voluntarily agreed to participate and provided written informed consent

You may not qualify if:

• History of spinal surgery or spinal deformity
• Infection or wounds at the puncture site
• Inability to maintain the lateral decubitus position
• Congenital lumbosacral transitional vertebrae (e.g., sacralized L5 or lumbarized S1)
• Any other condition deemed unsuitable for the study by the investigator

Sponsors & Collaborators

• Kangbuk Samsung Hospital: lead

Study Sites (2)

St. Vincent's Hospital

Suwon, North Carolina, 27516, South Korea

Location

Kangbuk Samsung Hospital

Seoul, 03181, South Korea

Location

MeSH Terms

Interventions

Palpation

Intervention Hierarchy (Ancestors)

Physical Examination; Diagnostic Techniques and Procedures; Diagnosis

Central Study Contacts

Sung Hyun Lee, MD, PhD

CONTACT

+82-2-2001-1666; hoho4321.lee@samsung.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: January 30, 2026
• First Posted: February 9, 2026
• Study Start: February 20, 2026
• Primary Completion (Estimated): February 20, 2027
• Study Completion (Estimated): February 20, 2028
• Last Updated: February 9, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

KR (2)