gms | German Medical Science

60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

Long-term outcome of shunted idiopathic normal pressure hydrocephalus patients and their cause of death in a prospective study

Meeting Abstract

  • M. Mirzayan - Neurochirurgische Klinik, Medizinische Hochschule Hannover
  • G. Lütjens - Neurochirurgische Klinik, Medizinische Hochschule Hannover
  • J. Borremans - Neurochirurgische Klinik, Albert-Ludwigs-Universität Freiburg
  • J. Regel - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Essen der Universität Duisburg-Essen
  • J. Krauss - Neurochirurgische Klinik, Medizinische Hochschule Hannover

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocMO.15-03

doi: 10.3205/09dgnc104, urn:nbn:de:0183-09dgnc1043

Published: May 20, 2009

© 2009 Mirzayan et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: Although the exact pathophysiology of idiopathic normal pressure hydrocephalus (iNPH) remains unclear, shunt surgery has been established as a long-term and effective treatment. We evaluated a prospective study cohort, which underwent cerebrospinal fluid (CSF) shunting between 1990 and 1995 to predict the benefit of shunt surgery at long-term follow-up. A secondary object of the study was to determine the cause of death of those patients, who died during follow-up.

Methods: Fifthy-one patients with suspected iNPH were included in this study. In all patients, the diagnosis of iNPH was confirmed by extensive clinical and diagnostic investigations. Shunt surgery included ventriculo-atrial or ventriculo-peritoneal shunts with differential pressure valves. For each of the cardinal symptoms,the postoperative outcome (at short-time and long-term follow-up) was assessed separately using a score where 0 means no or poor improvement; 1, fair or good improvement; 2, excellent improvement. According to these assessments, the overall symptomatic outcome of each patient was quantified by the calculation of the Krauss Improvement Index (KII). For this purpose, a fraction was formed with the numerator corresponding to the actual sum of improvement grades of all cardinal symptoms and the denominator corresponding to the possible maximal sum of improvement of the cardinal symptoms which were present preoperatively. This method yielded a value between 0 and 1.

Results: The mean age at surgery was 70.2 years (range: 50–87). Thirty patients were women, 21 were men. Early follow-up was available for 50 patients at a mean follow-up of 18.8 months (± 16.6). KII was 0.66 (± 0.28). Long-term follow-up at a mean time of 80.9 months (± 51.6) was available in 34 patients. KII at long-term follow-up was 0.71 (± 0.33). The last follow-up 12 years after the last patient was enrolled, revealed that 29 patients had died at a mean age of 75.8 years (range: 55–95). The major cause of death was cardiovascular disease: cardiac failure (n=7), cerebral ischemia (n=12), pneumonia (n=2), acute respiratory distress syndrome (n=1), pulmonary embolism (n=1), cancer (n=2), renal failure (n=1) and unknown reason (n=3). There was no shunt-related mortality.

Conclusions: Patients with iNPH benefit from shunt surgery in the long run when rigorous selection criteria are applied. Shunt related mortality is negligible. The main cause of death is the cardiovascular comorbidity.