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Updated: May 8, 2026

Spinal Sonography for Ultrasound-Guided Lumbar Neuraxial Anesthesia
Published on: January 31, 2025
Some epidurographic explanations for incomplete epidural analgesia coverage in the absence of a catheter
Eman M S Nada1, Mehmet Alparslan Turan, Mona N Mohamed
1Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; Assistant Consultant, Department of Anaesthesia and Pain Management, King AbdulAziz Medical City Saudi Arabia, Riyadh, Saudi Arabia; Lecturer, Department of Anesthesia, Alexandria University, Alexandria, Egypt.
Study Objective:
To determine the impact of the plica mediana dorsalis (PMD) on injected contrast media spread in the epidural space.
Design:
Prospective interventional study.
Setting:
Academic medical center.
Patients:
30 chronic pain patients ranging in age from 37 to 71 years, undergoing epidural steroid injection.
Interventions And Measurements:
Epidurograms were evaluated for the 1) presence or absence of a PMD and 2) bilateral differential density and the extent of contrast spread on either side of the midline, horizontally and vertically.
Results:
The PMD (defined as midline radiolucency in epidurograms) was observed in (80%) 24/30 patients based on the epidurograms that were evaluated. Denser contrast spread on one side was found in (79%) 19/24 patients who had the PMD and in (33%) 2/6 patients who did not have the PMD (P = 0.03). Horizontal and vertical asymmetrical spread of the contrast was observed in (67%) 16 of 24 patients with the PMD and in (50%) 3 of 6 of patients without the PMD in each direction independently.
Conclusion:
The difference in density of contrast spread on either side of the midline carries important clinical implications in understanding the pathogenesis of inadequate epidural analgesia and/or unilateral excessive motor weakness or numbness.
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