Value of Overnight Monitoring of Intracranial Pressure in Hydrocephalic Children

Objective: Exaggerated nocturnal intracranial pressure (ICP) dynamics are commonly observed in hydrocephalic children with a compromise of CSF compensatory reserve capacity. Successful shunting restores this cerebrospinal reserve. We used ICP overnight monitoring combined with positional maneuvers in complex hydrocephalic children with a suspected shunt malfunction for the assessment of shunt function.

Methods: In 32 hydrocephalic children, we performed 65 computerized overnight recordings and 25 positional maneuvers. Baseline ICP was considered abnormal if it exceeded the operating pressure of the shunt by more than 2.5 mm Hg. The maximum ICP (normal = <25 mm Hg), RAP coefficient (the correlation coefficient between pulse amplitude and mean intracranial pressure, which indicates pressure volume compensatory reserve; normal = <0.6), magnitude of slow waves (SLOW) and ICP pulse amplitude (AMP) were calculated for each night.

Results: Using baseline ICP, maximum ICP and RAP, 19 recordings were classified as 'normal' (group 1), 13 as 'questionable' (group 2), and 33 as 'pathological' (group 3) indicating shunt dysfunction or active hydrocephalus. ICP, AMP, RAP and SLOW were significantly different between groups and significantly elevated in group 3 compared to group 1. Positional tests identified shunt overdrainage in 5 of 25 occasions. In patients of group 1, who underwent revision, shunts turned out to be functional. All patients of group 3 eventually underwent shunt revision with improvement of symptoms thereafter.

Conclusion: Computerized ICP monitoring can benefit the assessment of shunt function, and can accurately characterize the status of CSF compensation in shunted children with a complex presentation.