The role of ICP overnight monitoring (ONM) in children with suspected craniostenosis.

Abstract

Secondary craniostenosis is a relevant problem pediatric neurosurgeons are confronted with and poses challenges regarding reliable diagnosis of raised ICP, especially in case of absent or questionable papilledema. How to identify children with elevated ICP is still controversial and diagnostics vary. We report on our experience with computerized ICP ONM in relation to imaging derived parameters. Thirty-four children with primary or secondary craniostenosis and clinical suspicion of raised ICP were investigated. We compared clinical signs, history, and radiographic assessment with the results of computerized ICP ONM. Differences were significant at a p < 0.05. Baseline ICP was significantly higher in patients with combined suture synostosis, who also had a higher rate of questionable papilledema. Children with narrowed external CSF spaces in MRI had significantly higher ICP levels during REM sleep. Mean RAP was significantly elevated in patients with multi-suture synostosis, indicating poor intracranial compensatory reserve. Syndromal craniostenosis was associated with elevated ICP, RAP was significantly lower, and skull X-rays showed more impressions (copper beaten skull). RAP increased with more severe impressions only to decline in most severe abnormalities, indicating exhaustion of cerebrovascular reserve at an upper ICP breakpoint of 23.9mmHg. Headaches correlated to lower ICP and were not associated with more severe X-ray abnormalities. Narrowed external CSF spaces in MRI seem to be associated to elevated ICP. Skull X-rays can help to identify patients at risk for chronically elevated ICP. Severe X-ray changes correlate with exhausted cerebrovascular reserve as indicated by RAP decline. Only ICP monitoring clearly identifies raised ICP and low brain compliance. Thus, in cases with ambiguous imaging, ONM constitutes an effective tool to acquire objective data for identification of surgical candidates.