Third ventricle floor bowing: a useful measurement to predict endoscopic third ventriculostomy success in infantile hydrocephalus.

BACKGROUND: Preoperative judgment who will benefit from endoscopic third ventriculostomy (ETV) in infantile hydrocephalus remains controversial and no sufficient clue exists. Although ETV success score (ETVSS) is a useful scale in predicting ETV success in hydrocephalus, its efficacy in infants younger than 1 year old has been limited. This study aimed to verify the efficacy of a newly defined sign, "third ventricle floor bowing (TVFB)," in predicting ETV success in infantile hydrocephalus for the first time and discuss the mechanism of this sign and its clinical meanings.

METHODS: Between January 2013 and April 2018, hydrocephalic infants (age ≤ 12 months) with third ventricle floor bowing were treated endoscopically in the Department of Neurosurgery, West China Hospital. The medical records of these patients were reviewed. Additionally, we undertook a detailed review of the reported data on the treatment of infantile hydrocephalus with endoscopic third ventriculostomy (ETV).

RESULTS: A total of 42 infants underwent ETV alone in our institution, with a median age of 7.3 ± 3.8 months. Common etiologies included postinfectious (26.2%), arachnoid cyst (14.3%), aqueductal stenosis (11.9%), and congenital condition (11.9%). The complications included seizure (2.4%), CSF leak (2.4%), and subdural effusion (2.4%). During the average follow-up of 21.7 ± 13.1 months, the ETV success rate predicted by third ventricle floor bowing (TVFB) was 71.4%, which was higher than 6-month success rate predicted by the ETVSS (52.3%). However, it was difficult to reach statistical significance (P = 0.072) due to the limited sample size and further studies with larger sample size were needed.

CONCLUSIONS: Our study suggests TVFB can serve as a useful method for selecting ETV candidates in infantile hydrocephalus preoperatively. And we speculate that good ventricle compliance and pressure difference between the ventricle and subarachnoid space are essential elements in ensuring ETV success.