Lamina Terminalis and Membrane of Liliequist Fenestration with Basal Cisternostomy: Permanent Cerebrospinal Fluid Diversion Rates in Aneurysmal Subarachnoid Hemorrhage in a Single-Center Retrospective Cohort Study
Siddharth Srinivasan, Mithun Sattur, Ajay Hegde, Rajesh P. Nair, Vishnu Suresh, Kevin Agyemang, Bharat Raju, Yasaswi Kanneganti, Udgam Baxi, Swamy Thippesha, Raviteja Jampani, Jordan Rasmussen, Daniel Surdell, Nicholas Borg, William Thorell, Sarah Johnson, Veeraditya Balal, Raghavendra Nayak, Girish MenonAbstract
Background:
Shunt-dependent hydrocephalus (ShDH) remains a source of morbidity after aneurysmal subarachnoid hemorrhage (aSAH). During microsurgical clipping, lamina terminalis (LT) fenestration with basal cisternostomy (BC) and membrane of Liliequist (MoL) fenestration (LTF-BC) can potentially reduce shunt dependency.
Objective:
To evaluate permanent cerebrospinal fluid (CSF) diversion rates and clinical outcomes in patients with aSAH undergoing microsurgical aneurysm occlusion with LTF-BC and MoL fenestration, and to identify factors associated with them.
Materials and Methods:
We performed a single-center retrospective cohort study using an institutional registry (2014–2023). Of 381 patients screened, 331 with ruptured aneurysms treated microsurgically with LTF-BC and MoL fenestration were included. Primary outcomes were permanent CSF diversion and 3-year functional outcome (modified Rankin Scale [mRS]). Multivariable logistic regression and Firth regression were performed. An external comparator analysis provided descriptive absolute risk reduction (ARR) and number needed to treat (NNT) estimates.
Results:
Median age was 55 years; 56.8% were women, 81.3% had Fisher grade III–IV hemorrhage, and 39.6% had acute hydrocephalus. Temporary CSF diversion was required in 50/131 (38.2%) patients with acute hydrocephalus. At 3 years, mRS was available for 326/331 patients; 244/326 (74.8%) had a good outcome (mRS 0–3). Permanent CSF diversion was performed in 9/331 patients (2.7%). Temporary CSF diversion was the only independent predictor of 3-year shunt dependency (odds ratio (OR) 5.08, 95% confidence interval (CI) 1.12–23.18;
Conclusion:
LTF-BC with MoL fenestration was associated with a low 3-year permanent CSF diversion rate despite high hemorrhage severity. Temporary CSF diversion identified a subgroup at increased risk for future shunt dependency.