Normal pressure hydrocephalus decreases the proliferation of oligodendrocyte progenitor cells and the expression of CNPase and MOG proteins in the corpus callosum before behavioral deficits occur.

Normal pressure hydrocephalus (NPH) compromises the morphology of the corpus callosum (CC). This study aims to determine whether 60- or 120-day NPH disrupts the cytoarchitecture and functioning of white matter (WM) and oligodendrocyte precursor cells (OPCs) and establish whether these changes are reversible after hydrocephalus treatment. NPH was induced in CD1 adult mice by inserting an obstructive lamina in the atrium of the aqueduct of Sylvius. Five groups were assembled: sham-operated controls (60 and 120 days), NPH groups (60 and 120 days), and the hydrocephalus-treated group (obstruction removal after 60-d hydrocephalus). We analyzed the cellular integrity of the CC by immunohistochemistry, TUNEL analysis, Western blot assays, and transmission electron microscopy (TEM). We found a reduction in the width of the CC at 60 and 120 days of NPH. TEM analysis demonstrated myelin abnormalities, degenerative changes in the WM, and an increase in the number of hyperdense (dark) axons that were associated with significant astrogliosis, and microglial reactivity. Hydrocephalus also caused a decrease in the expression of myelin-related proteins (MOG and CNPase) and reduced proliferation and population of OPCs, resulting in fewer mature oligodendrocytes. Hydrocephalus resolution only recovers the OPC proliferation and MOG protein density, but the rest of the WM abnormalities persisted. Interestingly, all these cellular and molecular anomalies occur in the absence of behavioral changes. The results suggest that NPH severely disrupts the myelin integrity and affects the OPC turnover in the CC. Remarkably, most of these deleterious events persist after hydrocephalus treatment, which suggests that a late treatment conveys irreversible changes in the WM of CC.

Assessing the utility of low resolution brain imaging: treatment of infant hydrocephalus.

As low-field MRI technology is being disseminated into clinical settings around the world, it is important to assess the image quality required to properly diagnose and treat a given disease and evaluate the role of machine learning algorithms, such as deep learning, in the enhancement of lower quality images. In this post hoc analysis of an ongoing randomized clinical trial, we assessed the diagnostic utility of reduced-quality and deep learning enhanced images for hydrocephalus treatment planning. CT images of post-infectious infant hydrocephalus were degraded in terms of spatial resolution, noise, and contrast between brain and CSF and enhanced using deep learning algorithms. Both degraded and enhanced images were presented to three experienced pediatric neurosurgeons accustomed to working in low- to middle-income countries (LMIC) for assessment of clinical utility in treatment planning for hydrocephalus. In addition, enhanced images were presented alongside their ground-truth CT counterparts in order to assess whether reconstruction errors caused by the deep learning enhancement routine were acceptable to the evaluators. Results indicate that image resolution and contrast-to-noise ratio between brain and CSF predict the likelihood of an image being characterized as useful for hydrocephalus treatment planning. Deep learning enhancement substantially increases contrast-to-noise ratio improving the apparent likelihood of the image being useful; however, deep learning enhancement introduces structural errors which create a substantial risk of misleading clinical interpretation. We find that images with lower quality than is customarily acceptable can be useful for hydrocephalus treatment planning. Moreover, low quality images may be preferable to images enhanced with deep learning, since they do not introduce the risk of misleading information which could misguide treatment decisions. These findings advocate for new standards in assessing acceptable image quality for clinical use.

Cerebellar mutism after posterior fossa tumor resection in children: a multicenter international retrospective study to determine possible modifiable factors.

PURPOSE: A preliminary survey of pediatric neurosurgeons working at different centers around the world suggested differences in clinical practice resulting in variation in the risk of pediatric cerebellar mutism (CM) and cerebellar mutism syndrome (CMS) after posterior fossa (PF) tumor resection. The purposes of this study were (1) to determine the incidence and severity of CM and CMS after midline PF tumor resection in children treated at these centers and (2) to identify potentially modifiable factors related to surgical management (rather than tumor biology) that correlate with the incidence of CM/CMS. METHODS: Attending pediatric neurosurgeons at British Columbia's Children's Hospital (BCCH) and neurosurgeons who completed a pediatric neurosurgery fellowship at BCCH were invited to provide data from the center where they currently practiced. Children aged from birth to less than 18 years who underwent initial midline PF tumor resection within a contemporary, center-selected 2-year period were included. Data was obtained by retrospective chart and imaging review. Modifiable surgical factors that were assessed included pre-resection surgical hydrocephalus treatment, surgical positioning, ultrasonic aspirator use, intraoperative external ventricular drain (EVD) use, surgical access route to the tumor, and extent of resection. CM was defined as decreased or absent speech output postoperatively and CMS as CM plus new or worsened irritability. RESULTS: There were 263 patients from 11 centers in 6 countries (Canada, Germany, the Netherlands, India, Indonesia, and the USA). Median age at surgery was 6 years (range < 1 to 17 years). The overall incidence of postoperative CM was 23.5% (range 14.7-47.6% for centers with data on ≥ 20 patients). The overall incidence of CMS was 6.5% (range 0-10.3% for centers contributing data on ≥ 20 patients). A multivariate logistic regression on the full data set showed no significant association between pre-resection surgical hydrocephalus treatment, prone position, ultrasonic aspirator use, EVD use, telovelar approach, complete or near total resection, or treating center and either postoperative CM or CMS. CONCLUSIONS: While there was variation in surgical management of midline PF tumors among centers participating in this study, the factors in management that were examined did not predict postoperative CM or CMS.

Prevalence and indication for changing the primary valve opening pressure in ventriculoperitoneal shunts - A single center five years overview.

OBJECTIVE: Serious medical conditions of patients in neurosurgery often require ventriculoperitoneal shunting to normalize the intracranial pressure. Neurosurgeons select a valve opening pressure (VOP), whose exceeding causes the shunt to open to drain cerebrospinal fluid (CSF): In most cases a standard pressure is chosen. Whereas some patients fare well with the primary chosen VOP, others require one to several VOP changes. This study aims to evaluate the prevalence and indication for occurring valve pressure-adjustments. PATIENTS AND METHODS: We obtained information about 343 ventriculoperitoneal shunt implantations in 321 adult patients from 2013 to 2018 in a single center with well-kept electronic health records regarding hydrocephalus types, hydrocephalus etiologies, primary VOP, valve pressure adjustment, time with shunt, time till VOP change, age, sex and shunt type. The data was analyzed using Kaplan-Meier estimator (KME) for the whole patient sample and for subgroups with the primary VOP adjustment defined as event. In the subgroup analysis different types of hydrocephalus, different hydrocephalus etiologies, valve types, both sexes and the patients' age had been compared by applying Peto-Pike's log-rank test and cox-regression. RESULTS: Of the 343 implanted VP shunts in 321 patients, 166 valve pressure adjustments in 101 V P shunts were required during the observed time with a resulting valve pressure-adjustment rate of 0.484 per valve implant. The time till median valve pressure-adjustment was 2.9 years and 38.3% one year after VP shunt placement for the general sample in Kaplan Meier-analysis. The subgroup comparisons between hydrocephalus types, hydrocephalus etiologies, valve types, sexes and the patients' age did not reveal significant differences applying Peto-Pike's log-rank test. But the primary chosen valve-pressure of 5 cmH2O is associated with a lower percentage of valve-pressure adjustments, than other initial valve-pressures (Chi2 = 7.9; df = 1; p = 0.0049). CONCLUSION: This study reveals a valve pressure-adjustment rate of 38.3% after one year for the whole patient collective and similar adjustment rates for different types of hydrocephalus. The primary valve pressure of 5 cmH2O is associated with a lower valve pressure-adjustment rate than other initial valve pressures and therefore 5 cmH2O may be the preferred initial valve pressure for all patients receiving programmable VP shunt insertions with gravitational unit.

The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus.