The Role of the Liliequist Membrane in the Third Ventriculostomy

Endoscopic third ventriculostomy (ETV) is a hydrocephalus treatment procedure that involves opening the Liliequist membrane (LM). However, LM anatomy has not been well-studied neuroendoscopically, because approach angles differ between descriptive and microsurgical anatomical explorations. Discrepancies in ETV efficacy, especially among children age 2 and younger, may be due to incomplete LM opening. The objective of this study was to characterize the LM anatomically from a neuroendoscopic perspective to better understand the impact of anatomical features during LM ostomy and the ETV success rate. Additionally, the ETV success score was tested to predict patient outcome after the intraoperatively difficult opening of LM. Fifty-four patients who underwent ETV were prospectively analyzed with a mean follow-up of 53.1 months (1–90 months). The ETV technical parameters of difficulty were validated by seven expert neurosurgeons. The pediatric population (44) of this study represents the majority of patients (81.4%). The overall ETV success rate was 68.5%. Anomalies on the IIIVT floor resulted in an increased rate of ETV failure. The IIIVT was anomalous, and LM was thick in 33.3% of cases. Fenestration of LM was difficult in 39% of cases, and the LM and TC were opened separately in 55.6% of cases. The endoscopic third ventriculostomy success score (ETVSS) accurately predicted the level of difficulty opening the LM (p = 0.012), and the group with easy opening presented greater durability in ETV success. Neurosurgeons should be aware of the difficulty level of the overture of LM during ETV and its impact on long-term ETV effectiveness.

Endoscopic third ventriculostomy success score in predicting short-term outcome in 68 children with hydrocephalus in a resource-limited tertiary centre in sub-Saharan Africa

Background Endoscopic third ventriculostomy (ETV) is becoming a popular option of treatment in carefully selected patients with hydrocephalus (Drake et al., Childs Nerv Syst 25:467-472, 2009). The success or possible outcome of its application in treating hydrocephalus can be predicted by employing a preoperative scoring system. An example of such a system is the endoscopic third ventriculostomy success score (ETVSS). It could form a basis for decision-making and prognostication. This study aimed to evaluate ETVSS as a preoperative predictive tool in children with hydrocephalus who satisfy the inclusion criteria for the option of ETV procedure as treatment modality. Methodology This is a prospective hospital-based study of 68 children under 2 years of age that presented at the Lagos University Teaching Hospital (LUTH) out of 161 children with hydrocephalus from November 2014 to April 2016. The predicted ETVSS was calculated by the addition of patients’ age, presumed aetiology and prior shunting. These children were stratified into three groups according to ETVSS as higher score predicts better ETV outcome and vice versa. They were followed up for 6 months to determine the success rate of ETV. Results The age of the study population ranged from 0 to 24 months with a mean age of 5.52 ± 5.48 months. 69.1% of these patients were male and 30.9% were female with a male to female ratio of 2.2:1. The mean predicted ETVSS (48.82 ± 19.20%) and actual ETV success score (56.20 ± 15.10%) using the ANOVA were significantly related (p value < 0.05). Conclusion This study concluded that the early outcome of ETV in children below 2 years of age with hydrocephalus is directly related to the preoperative ETVSS.

Evaluating the Children's Hospital of Alabama endoscopic third ventriculostomy experience using the Endoscopic Third Ventriculostomy Success Score: an external validation study

Object Endoscopic third ventriculostomy (ETV) success is dependent on patient characteristics including age, origin of hydrocephalus, and history of shunt therapy. Using these factors, an Endoscopic Third Ventriculostomy Success Score (ETVSS) model was constructed to predict success of therapy. This study reports a single-institution experience with ETV and explores the ETVSS model validity. Methods A retrospective chart review identified 151 consecutive patients who underwent ETV at a pediatric hospital between August 1995 and December 2009. Of these 151, 136 patients had at least 6 months of clinical follow-up. Data concerning patient characteristics, operative characteristics, radiological findings, complications, and success of ETV were collected. The actual success rates were compared with those predicted by the ETVSS model. Results The actual success rate of ETV at 6 months was 68.4% (93 of 136 patients), which compared well to the predicted ETVSS of 76.5% ± 12.5% (± SD). The C-statistic was 0.74 (95% CI 0.65–0.83), suggesting that the ability of the ETVSS to discriminate failures from successes was good. Secondary ETV was found to have a hazard ratio for failure of 4.2 (95% CI 2.4–7.2) compared with primary ETV (p < 0.001). The complication rate was 9.3% with no deaths. At the first radiological follow-up, the increased size of ventricles had a hazard ratio for failure of 3.0 (95% CI 1.5–6.0) compared with patients in whom ventricle size either remained stable or decreased (p = 0.002). Conclusions The ETVSS closely predicts the actual success of ETV, fitting the statistical model well. Shortcomings of the model were identified in overestimating success in patients with ETVSS ≤ 70, which may be attributable to the poor success of secondary ETVs in the authors' patient population.