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

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Estimated)

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 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

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
Intervention / Treatment
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

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

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

Al-Azhar University

Collaborators

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)

January 28, 2026

Primary Completion (Estimated)

November 30, 2026

Study Completion (Estimated)

December 30, 2026

Study Registration Dates

First Submitted

December 26, 2025

First Submitted That Met QC Criteria

January 17, 2026

First Posted (Actual)

January 22, 2026

Study Record Updates

Last Update Posted (Actual)

January 22, 2026

Last Update Submitted That Met QC Criteria

January 17, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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