Category: hydrocephalus

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Lumbar drain trial outcomes of normal pressure hydrocephalus: a single-center experience of 254 patients

J Neurosurg 132:306–312, 2020

A short-term lumbar drain (LD) trial is commonly used to assess the response of normal pressure hydrocephalus (NPH) patients to CSF diversion. However, it remains unknown whether the predictors of passing an LD trial match the predictors of improvement after ventriculoperitoneal shunting. The aim of this study was to examine outcomes, complication rates, and associations between predictors and outcomes after an LD trial in patients with NPH.

METHODS The authors retrospectively reviewed the records of 254 patients with probable NPH who underwent an LD trial between March 2008 and September 2017. Multivariate regression models were constructed to examine predictors of passing the LD trial. Complications associated with the LD trial procedure were recorded.

RESULTS The mean patient age was 77 years and 56.7% were male. The mean durations of gait disturbance, cognitive decline, and urinary incontinence were 29 months, 32 months, and 28 months, respectively. Of the 254 patients, 30% and 16% reported objective and subjective improvement after the LD trial, respectively. Complications included a sheared LD catheter, meningitis, lumbar epidural abscess, CSF leak at insertion site, transient lower extremity numbness, slurred speech, refractory headaches, and hyponatremia. Multivariate analyses using MAX-R revealed that a prior history of stroke predicted worse outcomes, while disproportionate subarachnoid spaces (uneven enlargement of supratentorial spaces) predicted better outcomes after the LD trial (r2 = 0.12, p < 0.05).

CONCLUSIONS The LD trial is generally safe and well tolerated. The best predictors of passing the LD trial include a negative history of stroke and having disproportionate subarachnoid spaces.

 

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Automatic volumetry of cerebrospinal fluid and brain volume in severe paediatric hydrocephalus, implementation and clinical course after intervention

Acta Neurochirurgica (2020) 162:23–30

In childhood hydrocephalus, both the amount of cerebrospinal fluid and the brain volume are relevant for the prognosis of the development and for therapy monitoring. Since classical planar measurements of ventricular size are subject to strong limitations, imprecise and neglect brain volume, 3D volumetry is most desirable. We used and evaluated the robust segmentation algorithms of the freely available FSL-toolbox in paediatric hydrocephalus patients before and after specific therapy.

Methods Retrospectively 76 pre- and postoperative high-resolution T2-weighted MRI sequences (true FISP, 1 mm isovoxel) were analyzed in 38 patients with paediatric hydrocephalus (mean 4.4 ± 5.1 years) who underwent surgical treatment (ventriculoperitoneal (VP) shunt n = 22, endoscopic third ventriculostomy (ETV) n = 16). After preprocessing, the 3D-datasets were skull stripped to estimate the inner skull surface. Following, a 2 class segmentation into different tissue types (brain matter and CSF) was performed. The volumes of CSF and brain were calculated.

Results The method could be implemented in an automated fashion in all 76MRIs. In the VP shunt cohort, the amount of CSF (p < 0.001) decreased. Consecutively brain volume increased significantly (p < 0.001). Following ETV, CSF volume (p = 0.019) decreased significantly (p = 0.012) although the reduction was less pronounced than after shunt implantation. Brain volume expanded (p = 0.02).

Conclusion A reliable automated segmentation of CSF and brain could be performed with the implemented algorithm. The method was able to track changes after therapy and detected significant differences in CSF and brain volumes after shunting and after ETV.

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Ventriculoperitoneal shunt in treating of idiopathic normal pressure hydrocephalus—single-center study

Acta Neurochirurgica (2020) 162:1–7

Idiopathic normal pressure hydrocephalus (iNPH) is the only variant of dementia disorders possibly treatable by neurosurgical intervention. iNPH is a neurodegenerative condition clinically characterized by gait ataxia, urinary incontinence, and memory disturbance. We present one of the largest single-center studies, which was designed to prove efficacy of our low-pressure setting of gravitational valve at all three symptoms of iNPH and to find statistically significant cut-off time for best clinical improvement according to the duration of symptoms.

Methods Sixty-one consecutive patients (mean age 74.9 ± 5.3) with iNPH were prospectively observed from the time of surgery with minimal 6 months follow-up. All patients underwent implantation of the same type of gravitational valve with the same setting—pro GAV with low opening pressure at 5 cm H2O—and were operated by the same team of 2 neurosurgeons. We statistically evaluated gait disturbance, psychological changes, and incontinence preoperatively and at 6 months after surgery and timing of the surgery according to the duration of symptoms and to the age.

Results Paired t test showed a statistically significant increase in MMSE, a statistically significant decrease in 10-m walk test and 360 deg. rotation test (p < 0.0001). The correlation among the change of the MMSE, the walk test, and the rotation test, and the age and time of symptoms’ duration was verified by Pearson’s correlation coefficient. Pearson’s correlation coefficient showed a medium strong correlation between the change of MMSE and the time of symptoms (r = − 0.580; p < 0.0001) and between the change of the number of steps and the time of symptoms (r = 0.517, p < 0.0001). There was a statistically significant weak (poor) correlation between the change of the walk test and the time of symptoms (r = 0.351, p = 0.006). All 3 ROC tests confirmed optimal cut-off for the best improvement of symptoms as 9.5 months of the symptom duration.

Conclusions We proved statistical significant optimal cut-off for the best improvement of the symptoms as 9.5 months of the symptom duration. This study also confirmed successful treatment of iNPH with VP shunting using low pressure setting of gravitational valve with overall improvement in 75% and low over drainage complications in 5%. We proved statistically significant increase in MMSE, decrease in 10 m walk test and number of steps test, p < 0.0001.

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Quantitative versus qualitative blood amount assessment as a predictor for shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage

J Neurosurg 131:1743–1750, 2019

Reliable tools are lacking to predict shunt-dependent hydrocephalus (SDHC) development after aneurysmal subarachnoid hemorrhage (aSAH). Quantitative volumetric measurement of hemorrhagic blood is a good predictor of SDHC but might be impractical in the clinical setting. Qualitative assessment performed using scales such as the modified Fisher scale (mFisher) and the original Graeb scale (oGraeb) is easier to conduct but provides limited predictive power. In between, the modified Graeb scale (mGraeb) keeps the simplicity of the qualitative scales yet adds assessment of acute hydrocephalus, which might improve SDHC-predicting capabilities. In this study the authors investigated the likely capabilities of the mGraeb and compared them with previously validated methods. This research also aimed to define a tailored mGraeb cutoff point for SDHC prediction.

METHODS The authors performed retrospective analysis of patients admitted to their institution with the diagnosis of aSAH between May 2013 and April 2016. Out of 168 patients, 78 were included for analysis after the application of predefined exclusion criteria. Univariate and multivariate analyses were conducted to evaluate the use of all 4 methods (quantitative volumetric assessment and the mFisher, oGraeb, and mGraeb scales) to predict the likelihood of SDHC development based on clinical data and blood amount assessment on initial CT scans.

RESULTS The mGraeb scale was demonstrated to be the most robust predictor of SDHC, with an area under the curve (AUC) of 0.848 (95% CI 0.763–0.933). According to the AUC results, the performance of the mGraeb scale was significantly better than that of the oGraeb scale (c 2 = 4.49; p = 0.034) and mFisher scale (c 2 = 7.21; p = 0.007). No statistical difference was found between the AUCs of the mGraeb and the quantitative volumetric measurement models (c = 12.76; p = 0.23), but mGraeb proved to be the simplest model since it showed the lowest Akaike information criterion (66.4), the lowest Bayesian information criterion (71.2), and the highest R 2 Nagelkerke coefficient (39.7%). The initial mGraeb showed more than 85% specificity for predicting the development of SDHC in patients presenting with a score of 12 or more points.

CONCLUSIONS According to the authors’ data, the mGraeb scale is the simplest model that correlates well with SDHC development. Due to limited scientific evidence of treatments aimed at SDHC prevention, we propose an mGraeb score higher than 12 to identify patients at risk with high specificity. This mGraeb cutoff point might also serve as a useful prognostic tool since patients with SDHC after aSAH have worse functional outcomes.

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Predicting Cognitive Improvement in Normal Pressure Hydrocephalus Patients Using Preoperative Neuropsychological Testing and Cerebrospinal Fluid Biomarkers

Neurosurgery 85:E662–E669, 2019

Though it is well known that normal pressure hydrocephalus (NPH) patients can cognitively improve after ventriculoperitoneal shunting (VPS), one of the major dilemmas in NPH is the ability to prospectively predict which patients will improve.

OBJECTIVE: To prospectively assess preoperative predictors of postshunt cognitive improvement.

METHODS: This was a prospective observational cohort including 52 consecutive patients with approximately 1-yr follow-up. Patients underwent neuropsychological testing at baseline, postlumbar drainage, and postshunt. Cerebrospinal fluid (CSF) biomarkers and cortical biopsies were also collected to examine their relationship with postshunt cognitive improvement.

RESULTS: Rey Auditory Verbal Learning Test-L (RAVLT-L) was the only neuropsychological test to demonstrate statistically significant improvement both postlumbar drain and postshunt. Improvement on the RAVLT-L postlumbar drain predicted improvement on the RAVLT-L postshunt. Patients with biopsies demonstrating Aβ+ Tau+ had lower ventricular CSF Aβ42 and higher lumbar CSF pTau compared to Aβ– Tau– patients. A receiver operating curve analysis using lumbar pTau predicted Aβ+ Tau+ biopsy status but was not related to neuropsychological test outcome.

CONCLUSION: The RAVLT can be a useful preoperative predictor of postoperative cognitive improvement, and thus, we recommend using the RAVLT to evaluate NPH patients. CSF biomarkers could not be related to neuropsychological test outcome. Future research in a larger patient sample will help determine the prospective utility of CSF biomarkers in the evaluation of NPH patients.

 

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Comparison of the CSF dynamics between patients with idiopathic normal pressure hydrocephalus and healthy volunteers

J Neurosurg 131:1018–1023, 2019

Intracranial pressure (ICP), outflow resistance (R out ), and amplitude of cardiac-related ICP pulsations (AMPs) are established parameters to describe the CSF hydrodynamic system and are assumed, but not confirmed, to be disturbed in idiopathic normal pressure hydrocephalus (INPH). The aim of this study was to compare the CSF hydrodynamic profile between patients with INPH and healthy volunteers.

METHODS Sixty-two consecutive INPH patients (mean age 74 years) and 40 healthy volunteers (mean age 70 years) were included. Diagnosis was made by two independent neurologists who assessed patients’ history, neurological status, and MRI studies. A CSF dynamic investigation through the lumbar route was performed: ICP and other CSF dynamic variables were blinded to the neurologists during the diagnostic process and were not used for establishing the diagnosis of INPH.

RESULTS R out was significantly higher in INPH (R out 17.1 vs 11.1; p < 0.001), though a substantial number of INPH subjects had normal R out . There were no differences between INPH patients and controls regarding ICP (mean 11.5 mm Hg). At resting pressure, there was a trend that AMP in INPH was increased (2.4 vs 2.0 mm Hg; p = 0.109). The relationship between AMP and ICP was that they shared the same slope, but the curve was significantly shifted to the left for INPH (reduced P 0 [p < 0.05]; i.e., higher AMP for the same ICP).

CONCLUSIONS This study established that the CSF dynamic profile of INPH deviates from that of healthy volunteers and that INPH should thus be regarded as a disease in which intracranial hydrodynamics are part of the pathophysiology.

Clinical trial registration no.: NCT01188382 (clinicaltrials.gov)

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Idiopathic Normal-Pressure Hydrocephalus: Diagnostic Accuracy of Automated Sulcal Morphometry in Patients With Ventriculomegaly

Neurosurgery 85:E747–E755, 2019

Idiopathic normal-pressure hydrocephalus (iNPH) is a treatable cause of gait and cognitive impairment. iNPH should be differentiated from ventriculomegaly secondary to brain atrophy to choose the best therapeutic option (ventriculoperitoneal shunt vs medical management).

OBJECTIVE: To determine the diagnostic accuracy of automated sulcal morphometry to differentiate patients with iNPH from patients with ventriculomegaly of neurodegenerative origin.

METHODS: Thirty-eight consecutive patients with iNPH (shunt responsive n = 31, nonresponsive n = 7), 35 with vascular cognitive disorder, and 25 age- and sex-matched healthy controls were prospectively included and underwent cognitive evaluation and 3T brain magnetic resonance imaging. Sulcal opening of 10 sulci of interest was retrospectively measured using an automated surface-based approach from the 3-dimensional T1-weighted images. Receiver-operating characteristic curve analyses determined the best parameter to identify iNPH patients.

RESULTS: The best parameter to discriminate shunt-responsive iNPH from patients with vascular cognitive disorder and healthy controls was the ratio between calcarine sulcus and cingulate sulcus opening with an area under the curve of 0.94 (95% CI: 0.89, 0.99). A cut-off value of 0.95 provided the highest sensitivity (96.8%) and specificity (83.3%).

CONCLUSION: This preliminary study showed that automated sulcal morphometry may help the neurosurgeon to identify iNPH patients and to exclude other causes of ventriculomegaly.

 

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Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

J Neurosurg 131:1024–1036, 2019

Different CSF diversion procedures (ventriculoperitoneal, ventriculoatrial, and lumboperitoneal shunting) have been utilized for the treatment of idiopathic normal pressure hydrocephalus. More recently, endoscopic third ventriculostomy has been suggested as a reasonable alternative in some studies. The purpose of this study was to perform a systematic review and meta-analysis to assess overall rates of favorable outcomes and adverse events for each of these treatments. An additional objective was to determine the outcomes and complication rates in relation to the type of valve utilized (fixed vs programmable).

METHODS Multiple databases (PubMed, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) were searched for studies involving patients with idiopathic ventriculomegaly, no secondary cause of hydrocephalus, opening pressure < 25 mm Hg on high-volume tap or drainage trial, and age > 60 years. Outcomes included the proportion of patients who showed improvement in gait, cognition, and bladder function. Adverse events considered in the analysis included postoperative ischemic/hemorrhagic complications, subdural fluid collections, seizures, need for revision surgery, and infection.

RESULTS A total of 33 studies, encompassing 2461 patients, were identified. More than 75% of patients experienced improvement after shunting, without significant differences among the different techniques utilized. Overall, gait improvement was observed in 75% of patients, cognitive function improvement in more than 60%, and improvement of incontinence in 55%. Adjustable valves were associated with a reduction in revisions (12% vs 32%) and subdural collections (9% vs 22%) as compared to fixed valves.

CONCLUSIONS Outcomes did not differ significantly among different CSF diversion techniques, and overall improvement was reported in more than 75% of patients. The use of programmable valves decreased the incidence of revision surgery and of subdural collections after surgery, potentially justifying the higher initial cost associated with these valves.

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Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus

J Neurosurg 131:1011–1017, 2019

Three to five days of external lumbar drainage (ELD) of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus (iNPH). The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.

METHODS Data of patients with iNPH who underwent 1-day ELD to be selected to undergo VPS placement with a programmable valve in the period from 2005 to 2015 were reviewed. Patients experiencing VPS complications, valve malfunctioning, or with less than 1 year of follow-up were excluded. The ability of 1-day ELD to predict VPS outcome at 1- and 12-month follow-up was assessed by calculating sensitivity, specificity, and positive and negative predictive values.

RESULTS Of 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test out- comes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity (95% confidence interval [CI] 19.5%–59.2%) and 100% specificity (95% CI 93.1%–100%) as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in
0 and 58 patients, respectively, at 1-month follow-up. Test sensitivity and specificity in predicting surgical outcome at 1-month follow-up were 100% (95% CI 92.3%–100%) and 60% (95% CI 27.4%–86.3%), respectively, with 94.1% accu- racy (95% CI 85.6–98.4%). Among the 1-day ELD–positive patients, 2 showed no clinical benefit at 12 months follow-up. Test sensitivity and specificity in predicting surgical outcome at 12-month follow-up was 100% (95% CI 92.5%–100%) and 75.0% (95% CI 35.6%–95.5%), respectively, with 97.1% (95% CI 89.8%–99.6%) accuracy.

CONCLUSIONS One-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at 1- and 12-month follow-up; negative-outcome patients have a high risk of unsuccessful surgery. Intraprocedural headache is prognostic of 1-day ELD negative outcome.

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Noninvasive Thermal Evaluation of Ventriculoperitoneal Shunt Patency and Cerebrospinal Fluid Flow Using a Flow Enhancing Device

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 240–249

While a noninvasive flow determination would be desirable in the diagnosis of cerebrospinal fluid shunt malfunction, existing studies have not yet defined a role for thermal flow detection.

OBJECTIVE: To evaluate a revised test protocol using a micropumper designed to transiently enhance flow during thermal testing to determine whether thermal detection of flow is associated with progression to shunt revision surgery.

METHODS: Eighty-two unique tests were performed in 71 shunts. The primary outcome, need for revision within 7 d of testing, was compared with results of micropumper-augmented thermal flow detection. Statistical analysis was based on blind interpretation of test results and raw temperature data recorded during testing.

RESULTS: The test was sensitive (73%) and specific (68%) in predicting need for revision, with 5.6-fold higher probability of revision when flow was not detected. Negative predictive value in our sample was 94.2%. The probability of not requiring revision increased with increasing total temperature drop. Analysis of various possible thresholds showed that the optimal temperature cutoff may be lower than suggested by the manufacturer (0.125◦C vs 0.2◦C).

CONCLUSION: This is the first study to report a strong association between thermal flow evaluation and a clinical impression that a shunt is not malfunctioning. The current recommended threshold may increase the false positive rate unnecessarily, and as clinicians gain experience with the method, they may find value in examining the temperature curves themselves. Multicenter studies are suggested to further define a role for this diagnostic test.

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Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles

J Neurosurg 130:1268–1273, 2019

External ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement.

METHODS Case notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded.

RESULTS A total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5–14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group.

CONCLUSIONS Image guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

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Global hydrocephalus epidemiology and incidence: systematic review and meta-analysis

J Neurosurg 130:1065–1079, 2019

Hydrocephalus is one of the most common brain disorders, yet a reliable assessment of the global burden of disease is lacking. The authors sought a reliable estimate of the prevalence and annual incidence of hydrocephalus worldwide.

METHODS The authors performed a systematic literature review and meta-analysis to estimate the incidence of congenital hydrocephalus by WHO region and World Bank income level using the MEDLINE/PubMed and Cochrane Database of Systematic Reviews databases. A global estimate of pediatric hydrocephalus was obtained by adding acquired forms of childhood hydrocephalus to the baseline congenital figures using neural tube defect (NTD) registry data and known proportions of posthemorrhagic and postinfectious cases. Adult forms of hydrocephalus were also examined qualitatively.

RESULTS Seventy-eight articles were included from the systematic review, representative of all WHO regions and each income level. The pooled incidence of congenital hydrocephalus was highest in Africa and Latin America (145 and 316 per 100,000 births, respectively) and lowest in the United States/Canada (68 per 100,000 births) (p for interaction < 0.1). The incidence was higher in low- and middle-income countries (123 per 100,000 births; 95% CI 98–152 births) than in high-income countries (79 per 100,000 births; 95% CI 68–90 births) (p for interaction < 0.01). While likely representing an underestimate, this model predicts that each year, nearly 400,000 new cases of pediatric hydrocephalus will develop worldwide. The greatest burden of disease falls on the African, Latin American, and Southeast Asian regions, accounting for three-quarters of the total volume of new cases. The high crude birth rate, greater proportion of patients with postinfectious etiology, and higher incidence of NTDs all contribute to a case volume in low- and middle-income countries that outweighs that in high-income countries by more than 20-fold. Global estimates of adult and other forms of acquired hydrocephalus are lacking.

CONCLUSIONS For the first time in a global model, the annual incidence of pediatric hydrocephalus is estimated. Low and middle-income countries incur the greatest burden of disease, particularly those within the African and Latin American regions. Reliable incidence and burden figures for adult forms of hydrocephalus are absent in the literature and warrant specific investigation. A global effort to address hydrocephalus in regions with the greatest demand is imperative to reduce disease incidence, morbidity, mortality, and disparities of access to treatment.

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Comparative durability and costs analysis of ventricular shunts

J Neurosurg 130:1252–1259, 2019

Ventricular shunt (VS) durability has been well studied in the pediatric population and in patients with normal pressure hydrocephalus; however, further evaluation in a more heterogeneous adult population is needed. This study aims to evaluate the effect of diagnosis and valve type—fixed versus programmable—on shunt durability and cost for placement of shunts in adult patients.

METHODS The authors retrospectively reviewed the medical records of all patients who underwent implantation of a VS for hydrocephalus at their institution over a 3-year period between August 2013 and October 2016 with a minimum postoperative follow-up of 6 months. The primary outcome was shunt revision, which was defined as reoperation for any indication after the initial procedure. Supply costs, shunt durability, and hydrocephalus etiologies were compared between fixed and programmable valves.

RESULTS A total of 417 patients underwent shunt placement during the index time frame, consisting of 62 fixed shunts (15%) and 355 programmable shunts (85%). The mean follow-up was 30 ± 12 (SD) months. The shunt revision rate was 22% for programmable pressure valves and 21% for fixed pressure valves (HR 1.1 [95% CI 0.6–1.8]). Shunt complications, such as valve failure, infection, and overdrainage, occurred with similar frequency across valve types. Kaplan-Meier survival curve analysis showed no difference in durability between fixed (mean 39 months) and programmable (mean 40 months) shunts (p = 0.980, log-rank test). The median shunt supply cost per index case and accounting for subsequent revisions was $3438 (interquartile range $2938–$3876) and $1504 (interquartile range $753–$1584) for programmable and fixed shunts, respectively (p < 0.001, Wilcoxon rank-sum test). Of all hydrocephalus etiologies, pseudotumor cerebri (HR 1.9 [95% CI 1.2–3.1]) and previous shunt malfunction (HR 1.8 [95% CI 1.2–2.7]) were found to significantly increase the risk of shunt revision. Within each diagnosis, there were no significant differences in revision rates between shunts with a fixed valve and shunts with a programmable valve.

CONCLUSIONS Long-term shunt revision rates are similar for fixed and programmable shunt pressure valves in adult patients. Hydrocephalus etiology may play a significant role in predicting shunt revision, although programmable valves incur higher supply costs regardless of initial diagnosis. Utilization of fixed pressure valves versus programmable pressure valves may reduce supply costs while maintaining similar revision rates. Given the importance of developing cost-effective management protocols, this study highlights the critical need for large-scale prospective observational studies and randomized clinical trials of ventricular shunt valve revisions and additional patient-centered outcomes.

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Safety and Efficacy of Endoscopic Third Ventriculostomy in Diffuse Intrinsic Pontine Glioma Related Hydrocephalus

World Neurosurg. (2019) 124:29-35

Diffuse intrinsic pontine glioma (DIPG) related hydrocephalus occurs as the result of tumor growth and sylvian aqueduct obstruction. There is no consensus about the best surgical option; thus, a review has been performed to clarify the rate of success, complications, and possible issues of endoscopic third ventriculostomy (ETV) in comparison to other available techniques.

METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (registration number CRD42018089001). MEDLINE, Web of Knowledge, and EMBASE were searched for published series in which ETV was performed to treat hydrocephalus in DIPG patients.

RESULTS: Six studies were included. Two further cases from our experience were added for a total amount of 55 patients treated through either ETV, ventriculoperitoneal shunt (VPS), or ventriculocisternal shunt according to Torkildsen. Eighty-six percent of patients who underwent ETV experienced clinical improvement after surgery (P value 0.03). Torkildsen shunt placement was associated with a 50% failure rate. Two patients implanted with VPS developed symptoms of shunt malfunction and increased ventricular sizes (10%). The Fisher exact test was applied to compare efficacy of VPS and ETV with no statistical difference between the 2 groups (P value 0.17). Patients who underwent ETV did not experience major complications, and no procedural termination was observed.

CONCLUSIONS: ETV is an effective and safe treatment option, associated with a low complication rate and a high success rate. Evidences from this review suggest considering ETV as the first-line treatment of hydrocephalus in DIPG patients.

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Prevalence of Schizophrenia in Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 84:883–889, 2019

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive and potentially treatable neurodegenerative disease affecting elderly people, characterized by gait impairment and ventricular enlargement in brain imaging. Similar findings are seen in some patients with schizophrenia (SCZ).

OBJECTIVE: To determine the prevalence of SCZ among patients suffering from probable or possible iNPH and the specific effects of comorbid SCZ on the outcome of the cerebrospinal fluid (CSF) shunting.

METHODS: All medical records of the 521 iNPH patients in the NPH registry were retrospectively analyzed from 1991 until 2017. The prevalence of comorbidity of SCZ was determined and compared to that of general aged (≥65 yr) population in Finland.

RESULTS: We identified a total of 16 (3.1%) iNPH patients suffering from comorbid SCZ. The prevalence of SCZ among the iNPH patients was significantly higher compared to the general population (3.1% vs 0.9%, P < .001). All iNPH patients with comorbid SCZ were CSF shunted and 12 (75%) had a clinically verified shunt response 3 to 12mo after the procedure. The CSF shunt response rate did not differ between patients with and without comorbid SCZ.

CONCLUSION: SCZ seems to occur 3 times more frequently among iNPH patients compared to the general aged population in Finland. The outcome of the treatment was not affected by comorbid SCZ and therefore iNPH patients suffering from comorbid SCZ should not be left untreated. These results merit validation in other populations. In addition, further research towards the potential connection between these chronic conditions is warranted.

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Diffusion tensor imaging and ventricle volume quantification in patients with chronic shunt-treated hydrocephalus

J Neurosurg 129:1611–1622, 2018

The object of this study was to use diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) to characterize the long-term effects of hydrocephalus and shunting on white matter integrity and to investigate the relationship of ventricular size and alterations in white matter integrity with headache and quality-of-life outcome measures.

METHODS Patients with shunt-treated hydrocephalus and age- and sex-matched healthy controls were recruited into the study and underwent anatomical and DTI imaging on a 3-T MRI scanner. All patients were clinically stable, had undergone CSF shunt placement before 2 years of age, and had a documented history of complaints of headaches. Outcome was scored based on the Headache Disability Inventory and the Hydrocephalus Outcome Questionnaire. Fractional anisotropy (FA) and other DTI-based measures (axial, radial, and mean diffusivity; AD, RD, and MD, respectively) were extracted in the corpus callosum and internal capsule with manual region-of-interest delineation and in other regions with TBSS. Paired t-tests, corrected with a 5% false discovery rate, were used to identify regions with significant differences between patients and controls. Within the patient group, linear regression models were used to investigate the relationship between FA or ventricular volume and outcome, as well as the effect of shunt-related covariates.

RESULTS Twenty-one hydrocephalus patients and 21 matched controls completed the study, and their data were used in the final analysis. The authors found significantly lower FA for patients than for controls in 20 of the 48 regions, mostly posterior white matter structures, in periventricular as well as more distal tracts. Of these 20 regions, 17 demonstrated increased RD, while only 5 showed increased MD and 3 showed decreased AD. No areas of increased FA were observed. Higher FA in specific periventricular white matter tracts, tending toward FA in controls, was associated with increased ventricular size, as well as improved clinical outcome.

CONCLUSIONS The study shows that TBSS-based DTI is a sensitive technique for elucidating changes in white matter structures due to hydrocephalus and chronic CSF shunting and provides preliminary evidence that DTI may be a valuable tool for tailoring shunt procedures to monitor ventricular size following shunting and achieve optimal outcome, as well as for guiding the development of alternate therapies for hydrocephalus.

 

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Value of whole-body low-dose computed tomography in patients with ventriculoperitoneal shunts: a retrospective study

J Neurosurg 129:1598–1603, 2018

The gold standard for evaluation of ventriculoperitoneal (VP) shunt position, dislocation, or disconnection is conventional radiography. Yet, assessment with this modality can be challenging because of low image quality and can result in repetitive radiation exposure with high fluctuation in the radiation dose. Recently, CT-based radiation doses have been significantly reduced by using low-dose protocols. Thus, whole-body low-dose CT (LDCT) has become applicable for routine use in VP shunt evaluation. The authors here compared image quality and approximate radiation dose between radiography and LDCT in patients with implanted VP shunt systems.

METHODS Ventriculoperitoneal shunt systems have been investigated with LDCT scanning at the authors’ department since 2015. A consecutive series of 57 patients (70 investigations) treated between 2015 and 2016 was retrospectively assessed. A historical patient cohort that had been evaluated with radiography was compared with the LDCT patients in terms of radiation dose and image quality. Three independent observers evaluated projection of the valve pressure level and correct intraperitoneal position, as well as complete shunt projection, using a Likert-type scale of 1–5, where 1 indicated “not assessable” and 5 meant “assessable with high accuracy.” Descriptive statistics and the Mann-Whitney U-test were used for analysis.

RESULTS Twenty-seven radiographs (38.6%) and 43 LDCT scans (61.4%) were analyzed. The median dose-length product (DLP) of the LDCT scans was 100 mGy·cm (range 59.9–183 mGy·cm). The median total dose-area product (DAP) of the radiographic images was 3177 mGy·cm2 (range 641–13,833 mGy·cm2). The estimated effective dose (EED) was significantly lower with the LDCT scan (p < 0.001). The median EED was 4.93 and 1.90 mSv for radiographs and LDCT, respectively. Significantly better identification of the abdominal position of the distal shunt catheter was achieved with LDCT (p < 0.001). Simultaneously, significantly improved visualization of the entire shunt system was realized with this technique (p < 0.001). On the contrary, identification of the valve settings was significantly worse with LDCT (p < 0.001).

CONCLUSIONS Whole-body LDCT scanning allows good visualization of the distal catheter after VP shunt placement. Despite the fact that only a rough estimation of effective doses is possible in a direct comparison of LDCT and radiography, the data showed that shunt assessment via LDCT does not lead to greater radiation exposure. Thus, especially in difficult anatomical conditions, as in patients who have undergone multiple intraabdominal surgeries, have a high BMI, or are immobile, the use of LDCT shunt evaluation has high clinical value. Further data are needed to determine the value of LDCT for the evaluation of complications or radiation dose in pediatric patients.

 

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Telemetry in intracranial pressure monitoring: sensor survival and drift

Acta Neurochirurgica (2018) 160:2137–2144

Telemetric intracranial pressure (ICP) monitoring enable long-term ICP monitoring on patients during normal day activities and may accordingly be of use during evaluation and treatment of complicated ICP disorders. However, the benefits of such equipment depend strongly on the validity of the recordings and how often the telemetric sensor needs to be re-implanted. This study investigates the clinical and technical sensor survival time and drift of the telemetric ICP sensor: Raumedic Neurovent-P-tel.

Methods Implanted telemetric ICP sensors in the period from January 2011 to December 2017 were identified, and medical records reviewed for complications, explantation reasons, and parameters relevant for determining clinical and technical sensor survival time. Explanted sensors were tested in an experimental setup to study baseline drift.

Results In total, implantation of 119 sensors were identified. Five sensors (4.2%) were explanted due to skin dResultsamage, three (2.5%) due to wound infection, and two (1.7%) due to ethylene oxide allergy. No other complications were observed. The median clinical sensor survival time was 208 days (95% CI 150–382). The median technical sensor survival time was 556 days (95% CI 382–605). Explanted sensors had a median baseline drift of 2.5 mmHg (IQR 2.0–5.5).

Conclusion In most cases, the ICP sensor provides reliable measurements beyond the approved implantation time of 90 days. Thus, the sensor should not be routinely removed after this period, if ICP monitoring is still indicated. However, some sensors showed technical malfunction prior to the CE-approval, underlining that caution should always be taken when analyzing telemetric ICP curves.

 

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Glaucoma in patients with shunt-treated normal pressure hydrocephalus

J Neurosurg 129:1078–1084, 2018

Changes in the pressure gradient between intraocular and intracranial compartments at the lamina cribrosa level are a possible explanation of normal tension glaucoma (NTG). Shunt-treated normal pressure hydrocephalus (NPH) is a model for testing whether the increase (time from disease onset to CSF shunt placement, i.e., “protection period”) and decrease (time from shunt placement to observation, i.e., “exposure period”) in intracranial pressure (ICP) are glaucoma protective or risk factors, respectively. The authors estimated the prevalence of NTG in patients with shunt-treated NPH and calculated the extent of optic nerve exposure to changes in the trans–lamina cribosa gradient.

METHODS Data obtained in patients with NPH who had undergone ventriculoperitoneal (VP) shunt placement were analyzed. Patients with more than 6 months’ follow-up, no pathologies associated with ICP changes or CSF dynamics disturbances, and no surgical or valve-related complications were scheduled for ophthalmic evaluation.

RESULTS Nine of 22 patients had NTG, which is about a 40-fold increase in rate compared with the rate in the general elderly population without hydrocephalus (p < 0.001). The median protection period was 12.0 months in patients with NTG and 18.0 months in those without NTG (p = 0.033). The median ICP decrease multiplied by duration of exposure in months was 76.0 mm Hg × months in the NTG group and 24.1 mm Hg × months in the no-NTG group (p = 0.048). The patients’ median adjusted age (adjusted for “protection” and “exposure” times) was 85.1 years in the NTG group and 78.8 years in the no-NTG group (p = 0.001).

CONCLUSIONS A crucial risk factor for development of NTG in patients with shunt-treated NPH is the duration of optic nerve exposure to the lowering of ICP. Patients with NPH who are candidates for CSF shunting should be informed of the risk of incurring glaucoma. Longitudinal studies could provide estimates of tolerated times for a given ICP decrease.

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