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

Completed

Conditions

Intervention / Treatment

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

Interventional

Enrollment (Actual)

100

Phase

  • 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

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
Intervention / Treatment
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

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

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

Instituto Nacional Materno Perinatal, Peru

Investigators

  • 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)

July 1, 2025

Primary Completion (Actual)

January 1, 2026

Study Completion (Actual)

January 1, 2026

Study Registration Dates

First Submitted

April 9, 2026

First Submitted That Met QC Criteria

April 17, 2026

First Posted (Actual)

April 24, 2026

Study Record Updates

Last Update Posted (Actual)

July 7, 2026

Last Update Submitted That Met QC Criteria

July 5, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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.

Clinical Trials on Obesity

Clinical Trials on Ultrasound-guided preprocedural marking

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in France

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe