Ultrasonographic ONSD as a Predictor of PDPH in Spinal Anesthesia for Cesarean Delivery

January 17, 2026 updated by: Neveen Abd El Maksoad Kohaf, Al-Azhar University

Early Prediction of Post-Dural Puncture Headache Using Ultrasound-Measured Optic Nerve Sheath Diameter in Cesarean Section Patients: A Prospective Observational Study

The Optic Nerve Sheath Diameter (ONSD), measured non-invasively by bedside ultrasound, is a well-established surrogate for intracranial pressure (ICP), as the optic nerve sheath is continuous with the intracranial dura mater and its subarachnoid space is filled with cerebrospinal fluid (CSF). While ONSD is typically used to detect elevated ICP (with a cut-off often > 5.0-5.7 mm for ICP > 20 mmHg), studies investigating PDPH have paradoxically shown a reduction in ONSD post-spinal anesthesia, correlating with the state of intracranial hypotension.

Previous research has demonstrated that a lower ONSD or a significant decrease in ONSD values 24 hours post-puncture is associated with PDPH development. A study determined that an ONSD at 24 hours of less than 0.40 cm was the best predictor for PDPH. Our study aims to specifically investigate the utility of the immediate change in ONSD to offer a bedside, real-time assessment of risk.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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.

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.
Observational

Enrollment (Estimated)

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.
150

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Egypt
    • Egypt
      • Cairo, Egypt, Egypt, 11865
        • Al-Azhar University
        • Contact:
        • Principal Investigator:
          • Hany Baumy, M.D

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

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Target Population:

The target population consists of adult female parturients who are medically eligible for spinal anesthesia and are undergoing elective cesarean delivery in a hospital setting.

Source Population:

The source population is defined as all consecutive adult female patients (aged 18-45 years, ASA II-III) who are admitted to Benha University Hospitals for an elective cesarean section during the study enrollment period (December 2025 - June 2026) and who meet the eligibility criteria.

Study Sample (Final Cohort):

The study sample will comprise 150 consenting patients drawn consecutively from the source population, forming a single observational cohort. These participants will undergo standardized spinal anesthesia and serial Optic Nerve Sheath Diameter (ONSD) measurements, with follow-up for Post-Dural Puncture Headache development over 72 hours.

Description

Inclusion Criteria:

  • Adult female patients, aged 18-45 years
  • ASA(American Society of Anesthesiologists) physical status II or III
  • Scheduled for elective cesarean section
  • Undergoing surgery under standardized spinal anesthesia

Exclusion Criteria:

  • Pre-existing headache disorders (e.g., migraine, chronic tension-type headache)
  • Known ophthalmic conditions (e.g., optic neuropathy, glaucoma)
  • Inability to cooperate with ONSD(Optic Nerve Sheath Diameter) ultrasound measurements or follow-up
  • Allergy to local anesthetics
  • Emergency cesarean section

  • Contraindications to spinal anesthesia:

    • Coagulopathy
    • Infection at the puncture site
  • Preexisting hypertension on medication
  • Pre-eclampsia with severe features (suggested for separate study)
  • Known cardiac disease with hemodynamic instability
  • Allergy to study drugs
  • Fetal distress or non-reassuring cardiotocography (CTG)
  • Body Mass Index (BMI) >40 kg/m²
  • Refusal to sign informed consent

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

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
Study Cohort (Single Cohort)

This study comprises a single, prospectively enrolled cohort of 150 adult female patients (ASA physical status II-III) scheduled for elective cesarean section under standardized spinal anesthesia. All participants receive the same planned intervention (spinal anesthesia for surgery) and undergo the same standardized measurement protocol for Optic Nerve Sheath Diameter (ONSD). Within this cohort, participants are naturally divided by outcome during follow-up into two groups for analytical purposes:

PDPH-Positive Subgroup: Patients who develop Post-Dural Puncture Headache (PDPH) within 72 hours, as diagnosed using the International Classification of Headache Disorders (ICHD-3) criteria.

PDPH-Negative Subgroup: Patients who do not develop PDPH within the follow-up period.
Procedure: Study Cohort (Single Cohort)

This study comprises a single, prospectively enrolled cohort of 150 adult female patients (ASA physical status II-III) scheduled for elective cesarean section under standardized spinal anesthesia. All participants receive the same planned intervention (spinal anesthesia for surgery) and undergo the same standardized measurement protocol for Optic Nerve Sheath Diameter (ONSD). Within this cohort, participants are naturally divided by outcome during follow-up into two groups for analytical purposes:

PDPH-Positive Subgroup: Patients who develop Post-Dural Puncture Headache (PDPH) within 72 hours, as diagnosed using the International Classification of Headache Disorders (ICHD-3) criteria.

PDPH-Negative Subgroup: Patients who do not develop PDPH within the follow-up period.

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
Optimal Delta ONSD cut-off value for predicting PDPH
Time Frame: 72 hours post-spinal.
To determine the numerical value of the change in Optic Nerve Sheath Diameter (Delta ONSD = ONSDpre - ONSDpost) that best predicts the development of PDPH.
72 hours post-spinal.

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
Post-Dural Puncture Headache (PDPH)
Time Frame: 72h.

To assess the intensity of headache pain. By Numeric Rating Scale (NRS):

0 (no pain) to 10 (worst imaginable pain).
72h.
The Need for Epidural Blood Patch (EBP)
Time Frame: 72 hour
The % of patients requiring an Epidural Blood Patch will de determined
72 hour

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.
Al-Azhar University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Benha University

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)

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.
January 28, 2026

Primary Completion (Estimated)

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.
November 30, 2026

Study Completion (Estimated)

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.
December 30, 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).
December 26, 2025

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.
January 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.
January 22, 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.
January 22, 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.
January 17, 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.
December 1, 2025

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.
  • RC. 1.12.2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data could be shared upon a reasonable request from the corresponding author

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

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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Conditions

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Dietary Supplements

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