Electrophysiological and fundoscopic detection of intracranial hypertension in craniosynostosis.

AIMS

To assess the diagnostic accuracy of fundoscopy and visual evoked potentials (VEPs) in detecting intracranial hypertension (IH) in patients with craniosynostosis undergoing spring-assisted posterior vault expansion (sPVE).

METHODS

Children with craniosynostosis undergoing sPVE and 48-hour intracranial pressure (ICP) monitoring were included in this single-centre, retrospective, diagnostic accuracy study. Data for ICP, fundoscopy and VEPs were analysed. Primary outcome measures were papilloedema on fundoscopy, VEP assessments and IH, defined as mean ICP > 20 mmHg. Diagnostic indices were calculated for fundoscopy and VEPs against IH. Secondary outcome measures included final visual outcomes.

RESULTS

Fundoscopic examinations were available for 35 children and isolated VEPs for 30 children, 22 of whom had at least three serial VEPs. Sensitivity was 32.1% for fundoscopy (95% confidence intervals [CI]: 15.9-52.4) and 58.3% for isolated VEPs (95% CI 36.6-77.9). Specificity for IH was 100% for fundoscopy (95% CI: 59.0-100) and 83.3% for isolated VEPs (95% CI: 35.9-99.6). Where longitudinal deterioration was suspected from some prVEPs but not corroborated by all, sensitivity increased to 70.6% (95% CI: 44.0-89.7), while specificity decreased to 60% (95% CI: 14.7-94.7). Where longitudinal deterioration was clinically significant, sensitivity decreased to 47.1% (23.0-72.2) and specificity increased to 100% (47.8-100). Median final BCVA was 0.24 logMAR (n = 36). UK driving standard BCVA was achieved by 26 patients (72.2%), defined as ≥0.30 logMAR in the better eye.

CONCLUSION

Papilloedema present on fundoscopy reliably indicated IH, but its absence did not exclude IH. VEP testing boosted sensitivity at the expense of specificity, depending on method of analysis.