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Diagnostic Intracranial Pressure Monitoring and Surgical Management in Idiopathic Normal Pressure Hydrocephalus: A 6Year Review of 214 Patients

Eide, Per Kristian MD, PhD; Sorteberg, Wilhelm MD, PhD

Neurosurgery:
doi: 10.1227/01.NEU.0000363408.69856.B8
Clinical Studies
Abstract

OBJECTIVE: To review our experience of managing idiopathic normal pressure hydrocephalus (iNPH) during the 6-year period from 2002 to 2007, when intracranial pressure (ICP) monitoring was part of the diagnostic workup.

METHODS: The review includes all iNPH patients undergoing diagnostic ICP monitoring during the years 2002 to 2007. Clinical grading was done prospectively using a normal pressure hydrocephalus (NPH) grading scale (scores from 3 to 15). The selection of patients for surgery was based on clinical symptoms, enlarged cerebral ventricles, and findings on ICP monitoring. The median follow-up time was 2 years (range, 0.3–6 years). Both static ICP and pulsatile ICP were analyzed.

RESULTS: A total of 214 patients underwent the diagnostic workup, of whom 131 went on to surgery. Although 1 patient died shortly after treatment, 103 of the 130 patients (79%) improved clinically. This improvement lasted throughout the observation period. The static ICP observed during ICP monitoring was a poor predictor of the response to surgery. In contrast, among 109 of 130 patients with increased ICP pulsatility (ie, ICP wave amplitude >4 mm Hg on average and >5 mm Hg in >10% of recording time), 101 (93%) were responders (ie, increase in the NPH score of >2). Correspondingly, only 2 of 21 (10%) without increased ICP pulsatility were responders. Superficial wound infection was the only complication of ICP monitoring and occurred in 4 (2%) patients.

CONCLUSION: Surgical results in iNPH were good with almost 80% of patients improving after treatment. The data indicate that improvement after surgery can be anticipated in 9 of 10 iNPH patients with abnormal ICP pulsatility, but in only 1 of 10 with normal ICP pulsatility. Diagnostic ICP monitoring had a low complication rate.

Author Information

Division of Clinical Neuroscience, Department of Neurosurgery, Rikshospitalet University Hospital, Oslo, Norway

Reprint requests: Per Kristian Eide, MD, PhD, Division of Clinical Neuroscience, Department of Neurosurgery, Rikshospitalet University Hospital, 0027 Oslo, Norway. E-mail: per.kristian.eide@rikshospitalet.no

Received, October 11, 2008.

Accepted, September 25, 2009.

Copyright © by the Congress of Neurological Surgeons