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Completed

NCT Number: NCT06711601

Ultrasound Evaluation of Two Anatomic Landmarks in Spinal Anesthesia for Cesarean Section: the Posterior Superior Iliac Spine VS Iliac Crest

Intercristal line as palpation landmarks to identifying the vertebral level is frequently inaccurate.To find more safe and reliable body surface markers and convenient methods to be solved in clinical work.The investigators performed a two-stage study to evaluated the accuracy of intercristal line and the The Posterior Superior Iliac Spine (PSIS) line to identify the lumbar interspinous spaces for spinal anesthesia using ultrasonography in pregnant woman which will provide a second option.

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Key information

Conditions

Spinal Anesthesia Intercristal Line Posterior Superior Iliac Spine Ultrasonography

Sex eligibility

Female

Study type

Observational

Primary location

The Third Affiliated Hospital of Guangzhou Medical University

Guangzhou, Guangdong, China

About this study

The investigators performed a two-stage study to evaluated the accuracy of Intercristal line and the PSIS line to identify the lumbar intervertebral space for spinal anesthesia using ultrasonography in pregnant woman. In phase 1, the distances between the PSIS line and each lumbar interspinous space is measured by ultrasound,and the mean and 95% confidence interval of distances in pregnant women with different height ranges were calculated to provide a reference for identifying specific lumbar spaces.In phase 2, a further 230 participants were received the PSIS, Intercristal line or both as palpation landmarks to define specific lumbar spaces.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • After obtaining written informed consents,pregnant women at 37-42 weeks of gestation

Exclusion criteria

  • BMI ≥ 40 kg/m² (to minimize palpation variability), History of lumbar surgery/deformity (scoliosis, spondylolisthesis or osteoporotic vertebral collapse), Inability to maintain the flexed lateral decubitus position, Participant withdrawal, Unforeseen anatomical anomalies discovered during screening.

Treatment and study plan

Primary outcomes

  1. The distance between the PSIS line and each mid-interspinous space

    Time frame: three days

    PSIS line was defined as an intercristal line drawn between the the final posterior superior iliac spine point.Use a ruler to measure the distance between the PSIS line and each midddle- interspinous space （L1/2 through L5/S1）and record. The mean of distances and 95% confidence interval are calculated.

  2. The accuracy of the anatomic landmarks to determine the L3/4 interspinous space

    Time frame: three days

    The L3-L4 intervertebral space was detected using intercristal line and the PSIS line in a random order by 2 experienced anesthesiologists. After determining the L3-L4 intervertebral space using each method alternately, horizontal skin marks were created with an erasable pen. Then, another experienced anesthesiologist for ultrasonographic examination assessed the intervertebral spaces.After identifying the sacrum, the investigator moved the probe in a cephalad direction, counted the intervertebral spaces and assessed the actual intervertebral spaces of the 2 skin marks.

Secondary outcomes

  1. The distance between the palpated intercristal line and PSIS line

    Time frame: three days

    palpated intercristal line line was identified and marked by bilateral palpation of the iliac crest summits.

    Subsequently, two reference points were defined: "point PSIS" (intersection of the PSIS line with the spinal midline) and "point PI" (intersection of the PI line with the spinal midline). We then calculated the following three distances: the "L3/4 distance" (from the L3/4 interspinous space midpoint to point PSIS), the "PI distance" (from point PI to point PSIS) The experienced anesthesiologist for ultrasonographic examination assessed the actual interspinous space of the intercristal line.

  2. baseline data

    Time frame: three days

    The age

  3. baseline data

    Time frame: three days

    body mass index (BMI)

  4. Maternal height

    Time frame: three days

    Maternal height

  5. baseline data

    Time frame: three days

    waist circumference

  6. baseline data

    Time frame: three days

    the gestational weeks

Sponsors and collaborators

Lead sponsor

The Third Affiliated Hospital of Guangzhou Medical University

Other

Registry information

Acronym: USPSISICL

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
Dec 2, 2024
Registry last updated
Jul 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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