Ultrasound-guided Versus Landmark-based Spinal Anesthesia in Obese Parturients Undergoing Cesarean Section (USLMCSEOB)

July 5, 2026 updated by: EDDISSON REYNALDO QUISPE PILCO, Instituto Nacional Materno Perinatal, Peru

Ultrasound-guided Versus Landmark-based Spinal Anesthesia in Obese Parturients Undergoing Cesarean Section: a Prospective Comparative Study

Spinal anesthesia is the most commonly used anesthetic technique for cesarean section. However, in obese parturients, identification of the optimal puncture site using anatomical landmark palpation can be challenging because of altered anatomy. Preprocedural ultrasound has been proposed as a tool to improve localization of the puncture site and facilitate neuraxial access.

This is a prospective comparative study included 100 obese parturients undergoing cesarean section under spinal anesthesia. Participants were allocated to one of two comparison groups according to the puncture site localization technique: a preprocedural ultrasound group and an anatomical landmark palpation group.

The primary outcome is the first-attempt success rate, defined as successful cerebrospinal fluid return after the first needle insertion without needle redirection or a new skin puncture. Secondary outcomes include the number of puncture attempts, needle redirections, need for rescue interventions, incidence of paresthesia and vascular puncture during the procedure, and procedural times.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This prospective comparative study aims to evaluate the effectiveness of preprocedural ultrasound-guided marking compared with the conventional anatomical landmark palpation technique for spinal anesthesia in obese parturients undergoing cesarean section.

A total of 100 parturients with a body mass index (BMI) ≥ 30 kg/m² were prospectively allocated to one of two comparison groups according to the puncture site localization technique. In the ultrasound group, the puncture site was identified using preprocedural ultrasound to determine the optimal intervertebral space and needle insertion trajectory. In the landmark group, the puncture site was identified using conventional anatomical landmark palpation.

The primary outcome was the first-attempt success rate, defined as successful cerebrospinal fluid return after the first needle insertion without needle redirection or an additional skin puncture. Secondary outcomes included the number of puncture attempts, needle redirections, need for rescue interventions, incidence of paresthesia and vascular puncture during needle insertion, and procedural times (site identification time, puncture time, and total procedure time).

This study evaluated whether preprocedural ultrasound-guided marking improves the technical performance of spinal anesthesia compared with conventional anatomical landmark palpation in obese parturients undergoing cesarean section.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Locations

  • Peru
    • Lima Province
      • Lima, Lima Province, Peru, 15001
        • National Maternal and Perinatal Institute

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥ 18 years
  • Pregnant women undergoing cesarean section
  • Body mass index (BMI) ≥ 30 kg/m² at the time of cesarean section
  • Scheduled for cesarean section under spinal anesthesia

Exclusion Criteria:

  • Congenital spinal deformities
  • History of spinal surgery
  • Coagulopathy
  • Infection at the puncture site
  • Allergy to local anesthetics
  • Emergency cesarean section (NICE category 1)

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

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Ultrasound-guided group
Preprocedural ultrasound was used to identify and mark the optimal puncture site in obese parturients undergoing cesarean section (n = 50).
Procedure: Ultrasound-guided preprocedural marking
Preprocedural ultrasound is used to identify and mark the optimal puncture site before spinal anesthesia.
Active Comparator: Landmark-based group
The puncture site was identified using anatomical landmark palpation in obese parturients undergoing cesarean section (n = 50)
Procedure: Landmark-based palpation
The puncture site is identified using anatomical landmark palpation before spinal anesthesia.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
First-attempt success rate of spinal anesthesia
Time Frame: During the spinal anesthesia procedure
Successful cerebrospinal fluid return after the first needle insertion without redirection.
During the spinal anesthesia procedure

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of puncture attempts
Time Frame: During the spinal anesthesia procedure
Total number of needle insertions required to achieve successful spinal anesthesia
During the spinal anesthesia procedure
Number of needle redirections
Time Frame: During the spinal anesthesia procedure
Number of needle redirections during a single puncture attempt
During the spinal anesthesia procedure
Need for rescue intervention
Time Frame: During the spinal anesthesia procedure
Requirement of assistance by a more experienced operator to complete the procedure
During the spinal anesthesia procedure
Incidence of paresthesia
Time Frame: During the spinal anesthesia procedure
Occurrence of paresthesia during needle insertion
During the spinal anesthesia procedure
Incidence of vascular puncture
Time Frame: During the spinal anesthesia procedure
Occurrence of vascular puncture during needle insertion
During the spinal anesthesia procedure
Total procedure time
Time Frame: During the spinal anesthesia procedure
Time from initial identification of the puncture site to successful cerebrospinal fluid return
During the spinal anesthesia procedure
Puncture time
Time Frame: During the spinal anesthesia procedure
Time from needle insertion to successful cerebrospinal fluid return
During the spinal anesthesia procedure

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Instituto Nacional Materno Perinatal, Peru

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Eddisson R Quispe Pilco, MD, National Maternal and Perinatal Institute

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 9, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 17, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 24, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 7, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 0107-DG-0080-OEAIDE-I

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

URL address will be offered or information will be sent by email.

IPD Sharing Time Frame

Beginning 3 months after publication and ending 12 months after publication

IPD Sharing Access Criteria

Access will be granted to researchers who provide a methodologically sound proposal. Proposals should be directed to the corresponding author via email. Data will be shared after approval of the proposal and signing of a data access agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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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