Ultrasonographic ONSD as a Predictor of PDPH in Spinal Anesthesia for Cesarean Delivery
Starting soon
Conditions studied: Cesarean Section Complications
In brief
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.
Key facts
- Study ID
- NCT07360756
- Run by
- Al-Azhar University
- People needed
- 150
- Starts
- 2026-01-28
- Expected to finish
- 2026-12-30
- Last updated by the study team
- 2026-01-22
Who can join
Age: 18 and older, up to 45. Sex: female. Healthy volunteers: not accepted.
You may qualify if…
- 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
You may not qualify if…
- 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
Where it is running
- Al-Azhar University — Cairo, Egypt, Egypt
Full record on ClinicalTrials.gov
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