Adjustable pressure valves for chronic hydrocephalus following subarachnoid hemorrhage: Is it worthwhile?

Objective: Compared to fixed pressure valves (FPV), adjustable pressure valves (APV) might reduce the rates of over/underdrainage necessitating revision surgery after shunt placement. But due to higher implant costs and valve vulnerability, the use APV in neurosurgery is still limited. The aim of this study was to evaluate the clinical utility of APV in patients with aneurysmal subarachnoid hemorrhage (aSAH).

Material and methods: All consecutive aSAH patients undergoing ventriculoperitoneal shunt (VPS) placement at our institution between 2003 and 2016 were eligible. Rates and the risk factors for shunt valve dysfunction and over/underdrainage were evaluated.

Results: A total of 189 patients were included in the final analysis. FPV were implanted in the majority of patients (173/91.5 %). Revision surgery due to over/underdrainage was performed in 8 (4.6 %) cases with FPV and in no case with APV. Higher patients' age (>65 years, p = 0.011; aOR 10.36) and bone flap reimplantation following decompressive craniectomy (p = 0.044; aOR 6.53) independently predicted the need for revision surgery for over/underdrainage. There was no difference in the occurrence of valve dysfunction between the two valve types (1 [6.3 %] APV, 12 [6.9 %] FPV), p > 0.99). Patients requiring revision surgery for over/underdrainage had a higher risk for unfavorable outcome at 6 months follow-up (mRS>3, p = 0.009; aOR = 8.0).

Conclusion: APV is a valuable option for aSAH individuals undergoing VPS implantation to reduce the need for revision surgery for over/underdrainage. Particularly, elderly patients and those requiring bone flap reimplantation might benefit from APV.