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

January 30, 2026 updated by: Sung Hyun Lee, Kangbuk Samsung Hospital

Evaluation of the Consistency of the ASIS Line for Lumbar Level Identification in the Lateral Decubitus Position: Comparison With the Tuffier's Line

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Estimated)

140

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • South Korea
    • North Carolina
      • Suwon, North Carolina, South Korea, 27516
        • St. Vincent's Hospital
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

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.

Description

Inclusion Criteria:

  • 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

Exclusion Criteria:

  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Study Cohort
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Consistency of Vertebral Level Identification (Standard Deviation)
Time Frame: Day 1 (Immediately during the ultrasound examination)
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 Outcome Measures

Outcome Measure
Measure Description
Time Frame
Difference in Mean Intersection Level
Time Frame: Day 1
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.
Day 1
Rate of Identification within L4-L5 Interspace
Time Frame: Day 1
The percentage of cases where the identified line falls within the target L4-L5 interspace (or within ±1 interspace range).
Day 1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Kangbuk Samsung Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

February 20, 2026

Primary Completion (Estimated)

February 20, 2027

Study Completion (Estimated)

February 20, 2028

Study Registration Dates

First Submitted

January 30, 2026

First Submitted That Met QC Criteria

January 30, 2026

First Posted (Actual)

February 9, 2026

Study Record Updates

Last Update Posted (Actual)

February 9, 2026

Last Update Submitted That Met QC Criteria

January 30, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-01-002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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