[Clinical experience with various shunt systems in normal pressure hydrocephalus]

Area of Science:

• Neurosurgery
• Neurology
• Medical Devices

Background:

• Conventional differential valves for normal pressure hydrocephalus (NPH) can cause abrupt opening and ventricular suction, especially in late-stage disease with brain atrophy.
• Overdrainage and related complications are significant concerns with current NPH valve technology.

Purpose of the Study:

• To evaluate if hydrostatic valves can minimize disadvantages and overdrainage complications associated with conventional differential valves in NPH patients.
• To compare the post-operative outcomes of three different valve types: Cordis Standard Valve (CSV), Cordis Orbis Sigma Valve Type I (OSV), and Miethke Dual Switch Valve (DSV).

Main Methods:

• 117 NPH patients were implanted with either CSV (n=47), OSV (n=20), or DSV (n=50).
• 95 patients were re-evaluated, with NPH staged by intrathecal infusion tests and clinical grading.
• Outcomes were compared based on NPH-Recovery-Rate and clinical grading, focusing on mechanical, infectious, and overdrainage complications.

Main Results:

• No statistical differences were found in mechanical or infectious complications among the valve types.
• Significant differences were observed in overdrainage and subdural hematomas: CSV (11%), OSV (26%), DSV (5%).
• Clinical symptoms related to overdrainage occurred in 6% of CSV, 16% of OSV, and 3% of DSV patients.

Conclusions:

• The stage of NPH, degree of cerebral atrophy, and implanted valve type influence disease progression.
• The high rate of overdrainage complications with the Cordis Orbis Sigma Valve Type I suggests it should be used cautiously.
• Clinical experience indicates the Miethke Dual Switch Valve, a hydrostatic valve, offers advantages for NPH patients.