Electrophysiological and fundoscopic detection of intracranial hypertension in craniosynostosis

Abstract

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.

Noninvasive methods to monitor intracranial pressure

“…Similar to prior VEP studies, pattern reversal VEPs or sustained giant pattern VEPs were not found to be reliable indicators of elevated ICP [135]. Pattern reversal VEPs were shown to have a sensitivity for elevated ICP that ranged between 58.3 and 70.6% [133] and sustained giant pattern VEPs incorrectly suggested elevated ICP in at least 20% of pediatric patients [135]. Therefore, it is unlikely that changes in VEP can be used to reliably detect changes in ICP and even less likely that it can provide a quantitative measurement of ICP.…”

“…More recent studies have looked at pattern reversal VEPs in patients with craniosynostosis and at sustained giant pattern VEPs (VEP amplitudes that exceeded the upper 97th percentile of VEP amplitudes) as markers of elevated ICP [133,135]. Similar to prior VEP studies, pattern reversal VEPs or sustained giant pattern VEPs were not found to be reliable indicators of elevated ICP [135].…”

“…Based on this work, VEPs were further studied as a potential noninvasive method to measure ICP. However, several studies found that VEPs did not change significantly in patients with elevated ICP; that there was a wide range of VEP latencies, amplitudes, and waveforms in normal subjects; and that there was a large variability over time in individual subjects, questioning the utility of VEPs as a noninvasive biomarker for ICP [133,134].…”

Current practices in temporal arachnoid cysts: a survey among Brazilian neurosurgeons

“…Regarding the further evaluation, although fundoscopy was the most requested exam in our population, its results should be interpreted with caution. Papilledema is the hallmark sign for intracranial hypertension (estimated specificity of 95%) [17], however, due to its low sensibility, its absence does not exclude the diagnosis [18][19][20].…”

What We Know About Intracranial Hypertension in Children With Syndromic Craniosynostosis

“…2,3,[5][6][7][8]18,[20][21][22]24,77,[84][85][86][87]92 A further 11 studies also used indirect methods of ICH assessment in addition to the invasive ICP or LP measurement. [9][10][11][12][13][14][15][16][17]19,23 Twenty-five studies used ICP, 3,[5][6][7][8]18,21,22,24,77,[84][85][86][87]89,93 one study used LP, 18 and 2 used ICP and LP 16,23 to determine ICH. Of the 25 studies using ICP, 21 reports both the duration and cut-off value.…”