Shunting normal-pressure hydrocephalus: Do the benefits outweigh the risks?
Department of Neurology, Academic Hospital, Free University of Amsterdam, The Netherlands. Neurology
(Impact Factor: 8.29).
02/1992; 42(1):54-9. DOI: 10.1212/WNL.42.1.54
We performed a multicenter retrospective study in 166 consecutive patients shunted for presumed normal-pressure hydrocephalus (NPH) in the four neurosurgical departments of Amsterdam. Overall improvement occurred in 36%, substantial improvement in 21%. In the subgroup of idiopathic NPH (N = 127), marked improvement was only 15%. The incidence of shunt-responsive NPH in our area was 2.2/million/year. The rate of severe and moderate shunt-related complications was 28%, leading to death or severe residual morbidity in 7%. The substantial benefit/serious harm ration in the whole group was only three (21%/7%), decreasing to 1.7 in idiopathic NPH. By excluding patients at high surgical risk, this ratio might have risen to 10 in the whole group and to six in idiopathic NPH. Our experience is much less favorable than that encountered in the literature, reporting overall improvement in 74% and marked improvement in 55% of the shunted patients. We conclude that NPH is probably a very rare and still overdiagnosed syndrome and that the overall morbidity rate for each patient demonstrating meaningful improvement is high.
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- "There have been few studies examining the epidemiology of iNPH. The first well-known incidence of NPH was 2.2/1,000,000 per year, which was described in a multicenter hospital-based study in Amsterdam . The researchers did not separate iNPH patients from other NPH patients. "
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The epidemiology and pathophysiology of iNPH remains unclear. We aimed to investigate the incidence of iNPH in elderly inhabitants of the community, and to identify how ventriculomegaly develops on brain MRIs and how symptoms develop in iNPH patients.
In 2000, 350 inhabitants, all of 70-year-olds living in the community of Takahata in Japan, were asked to participate in a survey that included a questionnaire, physical examinations, cognitive screenings, and brain MRI studies. Using brain MRI as a screening, we defined it as suspicious findings for iNPH that having both Evans index of > 0.3 and a narrow subarachnoid space and cortical sulci at the high convexity (tight high convexity, THC). Among the subjects who showed the iNPH feature on brain MRI, those who had gait disturbance and/or dementia were defined as possible iNPH. Twice during the 10 years, we administered the same check-up.
In the first survey, 271 inhabitants participated. During the 10 years, three new possible iNPH patients were found. The incidence of iNPH above 70 years old was estimated at 1.2/1000 persons per year. The iNPH patients developed their symptoms and brain MRI findings as follows; first, only THC without ventriculomegaly was observed on their brain MRIs, next, asymptomatic ventriculomegaly with features of iNPH on brain MRIs (AVIM) was seen, and then a final expression of symptoms of iNPH was shown.
The estimated incidence of iNPH in a community was higher than those estimated by previous studies where they collected patients at hospitals. There were subclinical or preclinical states before the development of iNPH.
Available from: Nicolas Gaillard
- "L'imagerie cé ré brale permet d'orienter le diagnostic mais peut parfois e ˆ tre d'interpré tation dé licate rendant la dé cision de dé rivation ventriculopé ritoné ale difficile a ` prendre (Kiefer et Unterberg, 2012). Cette dé cision est pourtant essentielle puisque l'amé lioration clinique n'est observé e que dans dix a ` 75 % des cas aprè s DVP (Vanneste et al., 1992 ; Hebb et Cusimano, 2001 ; Klassen et Ahlskog, 2011). Le taux de complication peut y e ˆ tre "
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ABSTRACT: INTRODUCTION: Normal pressure hydrocephalus (NPH) was described by Adams et al. (1965). The common clinical presentation is the triad: gait disturbance, cognitive decline and urinary incontinence. Although these symptoms are suggestive, they are not specific to diagnosis. The improvement of symptoms after high-volume lumbar puncture (hVLP) could be a strong criterion for diagnosis. We tried to determine a specific pattern of dynamic walking and posture parameters in NPH. Additionally, we tried to specify the evolution of these criteria after hVLP and to determine predictive values of ventriculoperitoneal shunting (VPS) efficiency. PATIENTS AND METHODS: Sixty-four patients were followed during seven years from January 2002 to June 2009. We identified three periods: before (S1), after hVLP (S2) and after VPS (S3). The following criteria concerned walking and posture parameters: walking parameters were speed, step length and step rhythm; posture parameters were statokinesigram total length and surface, length according to the surface (LFS), average value of equilibration for lateral movements (Xmoyen), anteroposterior movements (Ymoyen), total movement length in lateral axis (longX) and anteroposterior axis (longY). RESULTS: Among the 64 patients included, 22 had VPS and 16 were investigated in S3. All kinematic criteria are decreased in S1 compared with normal values. hVLP improved these criteria significantly (S2). Among posture parameters, only total length and surface of statokinesigram showed improvement in S1, but no improvement in S2. A gain in speed greater or equal to 0.15m/s between S1 and S2 predicted the efficacy of VPS with a positive predictive value (PPV) of 87.1% and a negative predictive value (NPV) of 69.7% (area under the ROC curve [AUC]: 0.86). CONCLUSION: Kinematic walking parameters are the most disruptive and are partially improved after hVLP. These parameters could be an interesting test for selecting candidates for VPS. These data have to be confirmed in a larger cohort.
Available from: Peter Black
- "SDH and hygroma 9.5%. Vanneste et al., 1992 (52) Retrospective "
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ABSTRACT: To develop evidence-based guidelines for surgical management of idiopathic normal-pressure hydrocephalus (INPH). Compared with the diagnostic phase, the surgical management of INPH has received less scientific attention. The quality of much of the literature concerning the surgical management has been limited by many factors. These include retrospective analysis, small patient numbers, analysis of a mixed NPH population, and sometimes a lack of detail as to what type of shunt system was used. Many earlier studies predated our current understanding of the hydrodynamics of cerebrospinal fluid shunts, and therefore, the conclusions drawn may no longer be valid.
A MEDLINE and PubMed search from 1966 to the present was conducted using the following key terms: normal-pressure hydrocephalus and idiopathic adult-onset hydrocephalus. Only English-language literature in peer-reviewed journals was reviewed. The search was further limited to articles that described the method of treatment and outcome selectively for INPH patients. Finally, only studies that included 20 or more INPH patients were considered with respect to formulating the recommendations in these Guidelines (27 articles).
For practical reasons, it is important to identify probable shunt responders diagnosed with INPH. If the patient is an acceptable candidate for anesthesia, then an INPH-specific risk-benefit analysis should be determined. In general, patients exhibiting negligible symptoms may not be suitable candidates for surgical management, given the known risks and complications associated with shunting INPH. The choice of valve type and setting should be based on empirical reasoning and a basic understanding of shunt hydrodynamics. The most conservative choice is a valve incorporating an antisiphon device, with the understanding that underdrainage (despite a low opening pressure) may occur in a small percentage of patients because of the antisiphon device. On the basis of retrospective studies, the use of an adjustable valve seems to be beneficial in the management of INPH.
The treatment of INPH should not be considered lightly, given the seriousness of the potential complications. Within these limitations and the available evidence, guidelines for surgical management were developed.
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