Spinal AnesthesiaUSPSISICLNCT06711601
Ultrasound Evaluation of Two Anatomic Landmarks in Spinal Anesthesia for Cesarean Section: the Posterior Superior Iliac Spine VS Iliac Crest
An observational study of Spinal Anesthesia and Ultrasonography, run by The Third Affiliated Hospital of Guangzhou Medical University at 1 site in China.
Trial summary
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… Read more about this study
- Who is it for?
- Any age, women only
- Conditions the study is for
- Spinal Anesthesia, Ultrasonography, Posterior Superior Iliac Spine
- How many people
- 650 participants
- Where
- 1 siteChina
- Study dates
- 1 Dec 2024to 23 Jan 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- Women only
- No healthy volunteers
- Child, Adult, Older adult
Study population: We enrolled parturients aged 22-45 years at 37-42 weeks of gestation scheduled for epidural or combined spinal-epidural anesthesia (for labor or cesarean section)
Who may be able to join
- After obtaining written informed consents,pregnant women at 37-42 weeks of gestation
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
China1 site
The Third Affiliated Hospital of Guangzhou Medical University
Guangzhou, Guangdong
About this study
Official title: 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.
Read the detailed description
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.
- Keywords
- cesarean section, ultrasonography, spinal anesthesia, Posterior Superior Iliac Spine, intercristal line
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| T group | The intercristal line-based palpation protocol followed the rule described by Kim et al[19], with minor modifications to accommodate the flexed lateral decubitus position: Select the interspinous space that is either intersected by the intercristal line or lies immediately below it. | |
| P group | The PSIS line-based palpation protocol stipulated targeting the L3/4 interspinous space within the an interval using hierarchical rules: single spaces are labeled L3/4; for two spaces, L3/4 is the intercristal line-intersected one (or lower if neither); for rare three spaces, the lowest is L3/4 | |
| Group M | Based on an interim analysis of Phase 1 data, we established the following decision protocol for L3/4 interspinous space localization: 1. PI ≥9 cm: Select the interspace at or immediately below the PI line. 2. PI ≤7 cm: Select the interspace at or immediately above the PI line. 3. PI 7-9 cm: Apply a 6.5-10 cm target window from the PSIS point. * If one interspace lies within this window, select it. * If multiple interspaces are present, choose the most caudal one. |
What is being measured
The primary outcome is the main question the study is designed to answer.
The distance between the PSIS line and each mid-interspinous space
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.
Measured: three days
The accuracy of the anatomic landmarks to determine the L3/4 interspinous space
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.
Measured: three days
Secondary outcomes (6)
The distance between the palpated intercristal line and PSIS line
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.
Measured: three days
baseline data
The age
Measured: three days
baseline data
body mass index (BMI)
Measured: three days
Maternal height
Maternal height
Measured: three days
baseline data
waist circumference
Measured: three days
baseline data
the gestational weeks
Measured: three days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Dec 2024
- Study start1 Dec 2024
- Primary completion30 Dec 2025
- Study completion23 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Spinal AnesthesiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 650 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Third Affiliated Hospital of Guangzhou Medical University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Souping Wang, PhD, Study director, The Third Affiliated Hospital of Guangzhou Medical University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06711601
- Sponsor's protocol ID
- [2024] No. 131
- Acronym
- USPSISICL
- Status last verified
- Jul 2026
- First submitted
- 18 Nov 2024
- Last updated
- 20 Jul 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ultrasound Evaluation Of Two Anatomic Landmarks In Spinal Anesthesia For Cesarean Section: The Posterior Superior Iliac Spine vs Iliac Crest
- ClinicalTrials.gov ID
- NCT06711601
- Acronym / sponsor ID
- USPSISICL / [2024] No. 131
- Keywords
- cesarean section, ultrasonography, spinal anesthesia, Posterior Superior Iliac Spine, intercristal line
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 650 participants (actual)
- Lead sponsor
- The Third Affiliated Hospital of Guangzhou Medical UniversityUniversity, hospital or other
- Study start
- 1 Dec 2024 (actual)
- Primary completion
- 30 Dec 2025 (actual)
- Study completion
- 23 Jan 2026 (actual)
- First posted
- 2 Dec 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| T group | – | –The intercristal line-based palpation protocol followed the rule described by Kim et al[19], with minor modifications to accommodate the flexed lateral decubitus position: Select the interspinous space that is either intersected by the intercristal line or lies immediately below it. |
| P group | – | –The PSIS line-based palpation protocol stipulated targeting the L3/4 interspinous space within the an interval using hierarchical rules: single spaces are labeled L3/4; for two spaces, L3/4 is the intercristal line-intersected one (or lower if neither); for rare three spaces, the lowest is L3/4 |
| Group M | – | –Based on an interim analysis of Phase 1 data, we established the following decision protocol for L3/4 interspinous space localization: 1. PI ≥9 cm: Select the interspace at or immediately below the PI line. 2. PI ≤7 cm: Select the interspace at or immediately above the PI line. 3. PI 7-9 cm: Apply a 6.5-10 cm target window from the PSIS point. * If one interspace lies within this window, select it. * If multiple interspaces are present, choose the most caudal one. |
Who may qualify
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- We enrolled parturients aged 22-45 years at 37-42 weeks of gestation scheduled for epidural or combined spinal-epidural anesthesia (for labor or cesarean section)
Key inclusion criteria (1 listed)
- After obtaining written informed consents,pregnant women at 37-42 weeks of gestation
Key exclusion criteria (1 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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.
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.
6 secondary outcomes
The distance between the palpated intercristal line and PSIS line
Time frame: three days
baseline data
Time frame: three days
baseline data
Time frame: three days
Maternal height
Time frame: three days
baseline data
Time frame: three days
baseline data
Time frame: three days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jul 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Souping Wang, PhD study director
The Third Affiliated Hospital of Guangzhou Medical University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Spinal Anesthesia and Ultrasonography, run by The Third Affiliated Hospital of Guangzhou Medical University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The distance between the PSIS line and each mid-interspinous space (time frame: three days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jul 2026.