Operator and Modality-Dependent Limitations of Optic Nerve Sheath Diameter Sonography for Raised ICP in TBI: A Meta-Regression of Diagnostic Accuracy
摘要
Optic nerve sheath diameter (ONSD) sonography has been investigated as a noninvasive tool for detecting elevated intracranial pressure (ICP) in traumatic brain injury (TBI), yet its diagnostic performance remains debated owing to variability in operator expertise and ultrasound modality.
MethodsThis systematic review and meta-analysis, registered in The International Prospective Register of Systematic Reviews (PROSPERO; CRD420251052612), included 15 eligible publications. Two studies reported both adult and pediatric cohorts, and several reported multiple modality or cutoff comparisons, yielding 17 pooled datasets (14 adult and 3 pediatric) and a total of 41 diagnostic reports for quantitative synthesis.
ResultsPooled estimates using a bivariate random-effects model demonstrated moderate-to-good diagnostic accuracy in adults, with a sensitivity of 0.88, specificity of 0.76, and an area under the curve (AUC) > 0.85 (moderate-certainty evidence). In contrast, pediatric datasets showed lower diagnostic performance, with a sensitivity of 0.82, specificity of 0.57, and AUC of 0.77 (low-certainty evidence). Meta-regression analyses identified ultrasound modality and operator background as significant contributors to diagnostic heterogeneity. B-mode ultrasonography modestly improved specificity, whereas examinations performed by nonspecialist operators were associated with reduced diagnostic accuracy. In contrast, commonly applied ONSD cutoff thresholds, including dichotomization at 5.5 mm or continuous analysis, were not significantly associated with diagnostic performance (p = 0.61).
ConclusionsThese findings suggest that ONSD sonography is a valuable, rapid, and noninvasive adjunct for detecting raised ICP in adults with TBI, though its reliability remains highly operator-dependent and limited in pediatric populations. Standardized measurement protocols, structured operator training, and pediatric-specific validation studies are needed before broader clinical adoption, particularly for integration into multimodal ICP monitoring strategies.