gms | German Medical Science

Objective: Ventriculomegaly with or without a shunt or persisting after endoscopic third ventriculostomy (ETV) without obvious signs or symptoms of raised intracranial pressure is most often interpreted as non-treatment dependent hydrocephalus, shunt independency or successful ETV. We hypothesized, that in the majority of cases increased nocturnal ICP dynamics and decreased compliance is present, which might have deleterious long-term effects.

Method: 42 children, fulfilling the above named criteria, underwent either computerized overnight ICP monitoring after implantation of an ICP sensor or a computerized shunt or ventricular reservoir infusion study. ICP and dependent calculated variables were analyzed for nocturnal ICP dynamics, ICP peak and baseline pressures, ICP amplitudes, indexes of decreased reserve capacity and compliance and findings indicating a pathophysiological situation of low compliance, increased ICP dynamics or shunt/ETV malfunction identified.

Results: In 14 of 21 ICP overnight monitorings, in 9 of 17 shunt infusions studies and in 3 of 6 reservoir infusion studies (after ETV) clearly abnormal patterns and results were found, indicating a pathological low compliance situation. Children either received shunt implantation or shunt revision. In 20 of 26 cases who received surgery parents reported some clinical improvement like better cognitive performance, less irritability, better sleep, or loss of headaches of their children after shunt revision/implantation. In all cases ventriculomegaly was regressing.

Conclusions: Decisions while treating hydrocephalus in childhood influence nowadays 70-80 years of future life. Ventriculomegaly in the absence of classical signs and symptoms of raised ICP was associated in more than 60% of cases with a pathological intracranial compliance situation with increased ICP dynamics. The persistence of a low intracranial compliance and increased ICP pulsatility and dynamics over years and decades can result in motor problems or cognitive decline, or if persistent into adulthood, early NPH development. Under these circumstances the common definition of ETV success (= absence of shunt) appears in a different light. Pediatric "asymptomatic" ventriculomegaly, if associated with abnormal ICP dynamics or blocked shunts, should be treated. With modern gravitational shunt systems the negative affects of persistent untreated normal pressure but low compliance hydrocephalus override negative side effects of shunting.