Article
Assessment of intracranial pressure and ventricular size in pediatric neurosurgery using combined ultrasound measurement of the Optic Nerve Sheath Diameter (ONSD) and Third Ventricle Diameter (TVD)
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Published: | June 18, 2018 |
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Objective: In neurosurgery a large number of pathologies is associated with increased intracranial pressure (ICP). ICP increase can be caused by hydrocephalus, idiopathic intracranial hypertension (IIH) or brain edema. Non-invasive diagnostics to assess ICP and differentiate between hydrocephalus and other entities are needed in pediatric and adult patients. This study aims to investigate the combined use of ultrasound ONSD and TVD to assess ICP and ventricular size in pediatric patients.
Methods: This prospective study includes 87 patients (median 7 years) diagnosed with hydrocephalus (53%), IIH (22%), tumor (8%) and other intracranial pathologies (17%). Binocular ONSD was measured transorbitally using a 12MHz linear probe. TVD was quantified with a transtemporal approach using a phased-array 1-4MHz transducer placed at the temporal window. All measurements were done with patient in supine position.
Results: 33 patients presented increased ONSD (mean 5.9±0.6mm) and TVD (mean 7.86±5.86mm) and underwent ICP decreasing therapy. In 14 patients ONSD (5.9±0.6mm) was enlarged while TVD (3.97±2.39mm) was only marginally increased. In these cases further diagnostic procedures were recommended. 40 patients presented with normal ONSD (4.98±0.6mm) and normal to marginally increased TVD (4.25±3.58mm). Watch-and-wait was performed and none needed an intervention up to now. In 21 patients TVD was measured before/after hydrocephalus therapy and in 7 without intervention. The relative difference of TVD was higher in patients with therapy (31 ± 19.7%) than without (4.8± 4.2%), p<0.001. A change of > 7.65% is highly sensitive and specific for true and relevant ventricle enlargement (sensitivity 90.5%, specificity 87.5%, AUROC 0.939, OR 57).
Conclusion: Transorbital ONSD is a reliable method to assess ICP and can be combined with transtemporal TVD for identification of possible ICP increases. Changes of TVD over time can be used for diagnosis of clinically relevant ventricular enlargements in pediatric patients.