Effects of external ventricular drainage decompression of intracranial hypertension on rebleeding of brain aneurysms: A fluid structure interaction study

Abstract

Objectives: The treatment of hydrocephalus using external ventricular drainage (EVD) seems to favour rebleeding of an untreated ruptured aneurysm. FSI studies are valuable to study this environment. Patients and methods: From December 2014 to December 2017, 61 patients with SAH required EVD due to hydrocephalus, 6 patients had aneurysm rebleeding after the procedure. Two controls for each case was included. DSA studies were used for fluid–structure interaction simulations using two scenarios high ICP (5332 Pa) and low ICP (133 Pa). Results: Maximum displacement of the wall in HICP was 0.34 mm and 0.26 mm in rebleeding and no rebleeding cases respectively, after EVD (LICP), it was 0.36 mm and 0.27 mm. The difference after implantation of EVD (HICP-LICP) had an average of 0.01567 mm and 0.00683 mm in rebleeding and no rebleeding cases (p = 0.05). This measure in low shear areas of the aneurysm was 0.026 and 0.0065 mm in rebleeding and no rebleeding cases (p = 0.01). Effective stress in the HICP was 4.77 MPa and 3.26 MPa in rebleeding and no rebleeding cases (p = 0.25). In LICP condition, this measure was 2.28 MPa and 1.42 MPa respectively (p = 0.33). TAWSS had no significant differences in the conditions of HICP and LICP. Conclusion: Changes after EVD placement includes an increase in the wall displacement with greater differences over low shear areas, this had a strong association with rebleeding.