Course of disease in patients with idiopathic normal pressure hydrocephalus (iNPH): a follow-up study 3, 4 and 5 years following shunt implantation

Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

OBJECTIVE

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS

Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS

Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8-5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I² of 97.5% (95% CI, 97.1-97.8; P < 0.001; τ² = 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (-2.11; 95% CI, -4.02 to -0.2; P = 0.031).

CONCLUSIONS

Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.

Management of idiopathic normal pressure hydrocephalus (iNPH) - a retrospective study

Background: Normal pressure hydrocephalus (NPH) is communicating hydrocephalus characterised by normal intraventricular pressures. It presents with the triad of gait impairment, cognitive decline, and urinary incontinence. The term idiopathic normal pressure hydrocephalus (iNPH) is used in cases where the etiology is unknown. The aim of this study was to assess the prevalence and management of iNPH in our institution.Method: This was a retrospective study carried out at a tertiary health care center. Retrospective case series analysis was conducted using the existing electronic medical record data (2009-2017) on patients with hydrocephalus.Results: Forty-two (6.7%) patients with iNPH were identified, mean age 71.5 ± 8.8 years, 21 male (mean age 71.5 ± 9.3 years) and 21 female (mean age 71.5 ± 8.5 years). Ataxia was recorded in 39, symptoms of dementia in 31, and urinary incontinence in 29 patients. Forty patients were treated surgically by placing a ventriculoperitoneal (VP) shunt. One of the two patients treated by endoscopic third ventriculostomy (ETV) was subsequently treated by placing a VP shunt due to clinical deterioration. Significant improvements were noticed in cognitive and urinary symptoms, in the triad symptom sum score on the Japanese NPH scale, as well as in Evans' index and callosal angle (CA) on brain MRI (p < 0.05). Significant positive correlation was found between age and gait disturbance (Spearman's rho = 49.86% p = 0.0017), age and incontinence (Spearman's rho = 35.22%, p = 0.0351), age and triad symptom sum score (Spearman's rho = 44.67%, p = 0.0056), female gender and dementia (Spearman's rho = 34.94%, p = 0.0367), and among all three variables on the Japanese NPH scale (p < 0.0001).Conclusions: Treatment of iNPH with VP shunt showed significant improvement. A properly designed study is required to address the efficacy of ETV in the treatment of iNPH.

Long-term 4 Years Follow-up Study of 482 Patients Who Underwent Shunting for Idiopathic Normal Pressure Hydrocephalus -Course of Symptoms and Shunt Efficacy Rates Compared by Age Group

A total of 482 operated idiopathic normal pressure hydrocephalus (iNPH) patients were divided into those aged <80 years at the time of surgery (group A: 400 cases; and male-to-female ratio, 259:141) and ≥80 years (group B: 82 cases; male-to-female ratio, 43:39) and comparatively investigated based on the following variables: (1) temporal changes in shunt efficacy rates, and (2) temporal changes in each symptom, including the patient’s fall frequency and preoperative modified Rankin Scale (mRS) score and during follow-up at 3, 6 months, 1–4 years postoperatively. (1) The shunt efficacy rates at 3 months and 4 years postoperatively were 93% and 82%, respectively, in group A and 92.3% and 70.7%, respectively, in group B. This demonstrates a decrease in shunt efficacy at 4 years postoperatively, regardless of the persistence of shunt function or adjustments in setting pressure. This trend was particularly observed in group B. In group A, 41 (9.8%) cases had decreased efficacy rate, compared with 21 (25.6%) cases in group B, which occurred due to complications with an extracranial or intracranial disease. (2) Gait disturbance (G) and urinary incontinence (U) showed signs of improvement in the early postoperative stage, while dementia (D) and mRS score began to gradually improve from 6 months postoperatively. Patient’s fall frequency tended to become higher until 6 months postoperatively than the preoperative rate. In group A, symptom improvement was comparatively maintained until 4 years postoperatively, while in group B, all symptoms and mRS tended to gradually deteriorate beginning at 3 years postoperatively.

Longitudinal Metabolite Profiling of Cerebrospinal Fluid in Normal Pressure Hydrocephalus Links Brain Metabolism with Exercise-Induced VEGF Production and Clinical Outcome

Idiopathic normal pressure hydrocephalus is a neurological disease caused by abnormal cerebrospinal fluid flow and presents with symptoms such as dementia. Current therapy involves the removal of excess cerebrospinal fluid by shunting. Not all patients respond to this therapy and biomarkers are needed that could facilitate the characterization of patients likely to benefit from this treatment. Here, we measure brain metabolism in normal pressure hydrocephalus patients by performing a novel longitudinal metabolomic profiling study of cerebrospinal fluid. We find that the levels of brain metabolites correlate with clinical parameters, the amount of vascular endothelial growth factor in the cerebrospinal fluid, and environmental stimuli such as exercise. Metabolomic analysis of normal pressure hydrocephalus patients provides insight into changes in brain metabolism that accompany cerebrospinal fluid disorders and may facilitate the development of new biomarkers for this condition.

Flow-related noise in patients with ventriculoperitoneal shunt using gravitational adjustable valves

BACKGROUND

Noise disturbance arising from the valve is a rare event of ventriculoperitoneal shunts. We queried and investigated shunt patients for occurrence and evaluated the possible factors related to noise development.

METHODS

Fifty ambulatory patients with implanted proGAV valve were investigated consecutively. Patients were asked for any noise arising from the shunt. In all cases, the valve was auscultated in sitting and upright position. The position of the gravitational unit (GU) was determined in respect to the Frankfurt horizontal plane (FHP) and in head reclination. Ten valves were perfused in vitro at different settings. One valve was opened for video documentation, and a frequency analysis of the noise was performed in nine valves.

RESULTS

Eight percent (4/50) of the patients reported a noise arising from the valve only in upright position in combination with maximum head reclination, and immediately stopped when performing Vasalva's maneuver. In three out of four of these patients, the noise was also audible for the investigator (FS) with a prepared stethoscope. Patients complaining about a noise had a larger GU deviation from vertical during head reclination (median: -80 vs -43°, p = 0.0007, t-test). A deviations threshold of less than -58.4° excluding audible noise by a negative predictive value of 1 (95 % confidence interval [CI] 0.9 to 1.0). In an experimental setting, the noise came from vibrations of the ball in the cone of the adjustable unit and was restricted to a flow of at least 220 ml/h. The noise frequencies tended to be higher at higher opening pressures.

CONCLUSIONS

Valve-related noise development may occur in patients with proGAV valves. This event could be prevented during shunt placement by avoiding posterior tilt of the gravitational unit, especially in patients with a good cervical mobility. The noise might indicate transient peak flows and was not associated with clinical or radiological signs of overdrainage.

Indications for valve-pressure adjustments of gravitational assisted valves in patients with idiopathic normal pressure hydrocephalus

Background:

Modern ventriculoperitoneal shunts (VPS) are programmable, which enables clinicians to adjust valve-pressure according to their patients’ individual needs. The aim of this retrospective analysis is to evaluate indications for valve-pressure adjustments in idiopathic normal pressure hydrocephalus (iNPH).

Methods:

Patients operated between 2004 and 2011 diagnosed with iNPH were included. Kiefer-Scale was used to classify each patient. Follow-up exams were conducted 3, 6, and 12 months after shunt implantation and yearly thereafter. Initial valve-pressure was 100 or 70 mmH₂O. Planned reductions of the valve-pressure to 70 and 50 mmH₂O, respectively, were carried out and reactive adjustment of the valve-pressure to avoid over- and under-drainage were indicated.

Results:

A total of 52 patients were provided with a Medos-Hakim valve^Codman® with a Miethke shunt-assistant^Aesculap® and 111 patients with a Miethke-proGAV^Aesculap®. 180 reductions of the valve-pressure took place (65% reactive, 35% planned). Most patients (89%) needed one or two adjustments of their valve-pressures for optimal results. In 41%, an improvement of the symptoms was observed. Gait disorder was improved most often after valve-pressure adjustments (32%). 18 times an elevation of valve-pressure was necessary because of headaches, vertigo, or the development of subdural hygroma. Optimal valve-pressure for most patients was around 50 mmH₂O (36%).

Conclusion:

The goal of shunt therapy in iNPH should usually be valve-pressure settings between 30 and 70 mmH₂O. Reactive adjustments of the valve-pressure are useful for therapy of over- and underdrainage symptoms. Planned reductions of the valve opening pressure are effective even if postoperative results are already satisfactory.

Cortical brain biopsy in long-term prognostication of 468 patients with possible normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) can be alleviated by cerebrospinal fluid shunting but the differential diagnosis and patient selection are challenging. Intraventricular intracranial pressure monitoring as part of the diagnostic workup as well as shunting enable to obtain cortical brain biopsies to detect amyloid-β (Aβ) and hyperphosphorylated tau (HPτ), the hallmark lesions of Alzheimer's disease (AD). In possible NPH, Aβ alone indicates an increased risk of AD and when present with HPτ probable AD, but the effect of those brain lesions on survival is not known. The aim of this study was to evaluate the predictive value of brain biopsy for the long-term outcome of possible NPH. Between 1991 and 2006, the Neurosurgery Department of the Kuopio University Hospital evaluated 468 patients for possible NPH by intraventricular intracranial pressure monitoring and frontal cortical brain biopsy immunostained against Aβ and HPτ. All patients were followed up until the end of 2008 (n = 201) or death (n = 267) with a median follow-up of 4.6 years (range 0-17). Logistic regression analysis with Cox models was applied. Out of the 468 cases, Aβ was detected in 197 (42%) cortical biopsies, and together with HPτ in 44 (9%). Aβ alone indicated increased risk of AD and with HPτ probable AD, but it did not affect survival. Vascular aetiology was the most frequent cause of death. Cortical biopsy findings indicate that NPH is at present a heterogeneous syndrome and has notable overlapping with AD. Brain biopsy did not predict survival but may open a novel research window to study the pathobiology of neurodegeneration.

The differential diagnosis and treatment of normal-pressure hydrocephalus

BACKGROUND

Normal-pressure hydrocephalus (NPH) arises in adulthood and is characterized by a typical combination of clinical and radiological findings. The mean basal intracranial pressure is normal or mildly elevated. The typical signs of the disease are gait impairment, urinary incontinence, and dementia. The difficulty of distinguishing NPH from other neurodegenerative disorders is the likely reason why some 80% of cases remain unrecognized and untreated. According to current evidence, the spontaneous course of NPH ends, for the vast majority of patients, in dependence on nursing care.

METHODS

This review article is based on relevant publications retrieved by a selective search in Medline and on national and international guidelines for the management of NPH.

RESULTS

Studies with a high evidence level are lacking; thus, the current state of knowledge about NPH is derived from studies of low or intermediate evidence levels, e.g., observational studies. Modern forms of treatment lead to clinical improvement in 70% to 90% of treated patients. The treatment of choice is the implantation of a ventriculoperitoneal shunt. The differential diagnosis is complicated by the fact that three-quarters of patients with NPH severe enough to require treatment also suffer from another neurodegenerative disorder. Therefore, the clinical findings and imaging studies often do not suffice to establish the indication for surgery. To do this, a further, semi-invasive diagnostic procedure is recommended. Current risk/benefit analyses indicate that shunt operations improve outcome compared to the spontaneous course of the disease.

CONCLUSION

Normal pressure hydrocephalus should always enter into the differential diagnosis of patients who present with its characteristic manifestations. If the diagnosis of NPH is confirmed, it should be treated at an early stage.

An overview of normal pressure hydrocephalus and its importance: how much do we really know?

Normal pressure hydrocephalus (NPH) is a clinical triad of gait disturbance, dementia, and urinary incontinence combined with radiographic findings of ventriculomegaly and laboratory findings of normal cerebrospinal fluid pressures. Although it was first described by Hakim and Adams in 1965, there is no formal definition of NPH, causing discrepancy in its incidence in various studies. This ranges from 2 to 20 per million per year. It is estimated to be the cause of about 5% of cases of dementia and is one of the few reversible causes of dementia. Early diagnosis increases the rate of success to treatment. This makes accurate diagnosis and identification of responders to treatment important. There have been various studies on NPH in the general population, but not much has been said about it in long-term care facilities and the question arises on how many cases are missed. If a screening tool is in place to identify possible cases then further workup could be done to confirm the diagnosis and determine the need for shunting.

Laparoscopy-assisted ventriculoperitoneal shunt surgery: personal experience and review of the literature

Ventriculoperitoneal shunting is a widely accepted technique for the treatment of hydrocephalus. The standard procedure to insert the peritoneal catheter requires an abdominal incision, muscle dissection, and opening of the peritoneum. A number of complications related to the abdominal surgical phase have been reported. Laparoscopy-assisted ventriculoperitoneal shunting is a valid alternative procedure that reduces surgical trauma. We describe our experience and review the literature. A total of 30 laparoscopically guided ventriculoperitoneal shunting procedures were performed between January 2007 and June 2008, in collaboration with a general surgeon experienced in laparoscopy. Of these procedures, 25 were new shunt placements and 5 were revisions. Data about operative time, outcome, and complications were registered and compared with a group of 30 patients treated by means of standard laparotomy in the period 2005-2007. Laparoscopic shunt placement was successful in all patients. Operative duration, complications, and postoperative pain were all lower in patients treated by laparoscopy as compared to the laparotomy. In the laparoscopic group, an earlier peristalsis, quicker mobilization, and better cosmetic results were also noted. Laparoscopy in both ventriculoperitoneal shunt placement and revision is a safe, effective, and minimally invasive technique. It ensures proper abdominal placement of the distal catheter under direct vision allowing confirmation of its patency.

Segmental copy number loss of SFMBT1 gene in elderly individuals with ventriculomegaly: a community-based study

OBJECTIVE

Idiopathic normal pressure hydrocephalus (iNPH) is clinically important as a treatable gait disturbance or preventable dementia by shunt operation. We have recently reported that approximately 1.5% of the elderly living in a Japanese community showed ventriculomegaly with features of iNPH on MRI (VIM), which may represent a preclinical stage of iNPH. The purpose of the present study was to identify a possible genetic change in VIM subjects.

METHODS

Eight subjects with VIM and 10 healthy individuals were examined for copy number variations (CNV) with a CNV-targeted whole-genome oligonucleotide microarray (Agilent 400 K CNV array). Another panel of 100 healthy Japanese individuals was screened for CNV by whole-genome using the deCODE-Illumina CNV 370 K chip. Immunohistochemical examination of the human brain was performed using an avidin-biotin-peroxidase complex method.

RESULTS

Among several genetic changes observed, a copy number loss within the SFMBT1 gene was seen in half of the VIM cases (4 of 8 cases), that was rare among the Japanese control subjects (0/10 by Agilent 400 K CNV array or 1/100 by deCODE/Illumina CNV 370 K chip). Immunohistochemical examination of the human brain revealed that the SFMBT1 protein was localized mainly in the arterial walls, the ependymal cells, and the epithelium of the choroid plexus, all of which play a crucial role in the CSF circulation.

CONCLUSION

A segmental copy number loss of the SFMBT1 gene may be involved in the pathological process in some individuals with VIM/iNPH.