Article
Secondary deterioration in idiopathic normal pressure hydrocephalus in the very long term – treatable or not? A retrospective analysis
Sekundäre Verschlechterung bei iNPH – behandelbar oder nicht?
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Published: | June 26, 2020 |
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Objective: Cerebrospinal fluid (CSF) shunting is a highly effective treatment in iNPH, but secondary deterioration can occur in the later course. The aim of this study was to evaluate the rate and causes of secondary deterioration.
Methods: A retrospective analysis of all patients with iNPH treated with CSF-shunt implantation since 1993 was performed. All patients with a secondary deterioration were offered a meticulous "shunt work up". Data related to the number and causes of deteriorations, the subsequent treatment, and the clinical outcome was extracted.
Results: A total of 169 patients with a mean follow-up of 69.2 months could be included. 119 patients (70.4%) experienced a total of 153 secondary deteriorations. In 9 cases delayed subdural haematoma caused the deterioration. In 27 events the cause for deterioration was a proven shunt dysfunction (22.1%). Invasive shunt testing was frequently necessary to confirm shunt failure. The majority of patients (19/27) experienced a good improvement after revision surgery. 86 deteriorations were due to non-surgical causes and the valve pressure was lowered in 79 patients, with only 16.5% showing good amelioration of symptoms.
Conclusion: The majority of shunted iNPH patients deteriorate in the long term. Shunt dysfunction is a valid cause of secondary deterioration. Since shunt revision surgery is highly effective, we recommend that patients with deterioration are screened for shunt dysfunction including invasive shunt testing.