Abstract
Introduction Unlike low-pressure hydrocephalus, very low pressure hydrocephalus (VLPH) is a rarely
reported clinical entity previously described to be associated with poor outcomes
and to be possibly refractory to treatment with continued cerebrospinal fluid (CSF)
drainage at subatmospheric pressures.1, 2 We present four cases of VLPH following resection of suprasellar lesions and hypothesize
that untreatable patients can be identified early, thereby avoiding futile prolonged
external ventricular drainage in ICU.
Methods We performed a retrospective chart review of four cases of VLPH encountered between
2007 and 2015 in two different institutions and practices and tried to identify factors
contributing to successful treatment. We hypothesized that normalization of frontal
horn ratio (FHR), optimization of volume of CSF drained, and avoidance of fluid shifts
would contribute to improved Glasgow Coma Score (GCS). We examined fluid shifts by
studying net fluids shifts and serum levels of sodium, urea, and creatinine. We used
Pearson and Spearman correlations to identify measures that would correlate with improved
GCS.
Results Our study reveals that improving GCS is positively correlated with decreased FHR
and increased CSF drainage within an optimal range. The most important determinant
of good outcome is retention of brain viscoelasticity as evidenced by restoration
and maintenance of good GCS score despite fluctuations in FHR.
Conclusion Futile prolonged subatmospheric drainage can be avoided by declining to continue
treatment in patients who have permanently altered brain compliance secondary to unsealed
CSF leaks, irremediable ventriculitis, and who are therefore unable to sustain an
improved neurologic examination.
Keywords
very low pressure hydrocephalus (VLPH) - CSF leak - frontal horn ratio - anterior
skull base surgery - transsphenoidal surgery - suprasellar lesions
