Neuroimaging of ventriculoperitoneal shunt complications in children

Ventriculoperitoneal Shunt Surgery in Pediatrics: Does Preoperative Skin Antisepsis with Chlorhexidine/Alcohol Reduce Postoperative Shunt Infection Rate?

BACKGROUND

 In pediatrics, shunt infection is considered the most common complication of ventriculoperitoneal (VP) shunt insertion and the main cause of shunt failure. Careful surgical technique and hygienic skin preparations are highly important for prevention of shunt infections. Our objective was to assess the significance of using preoperative chlorhexidine/alcohol as a skin antiseptic in reducing the infection rate in pediatric VP shunts surgery.

METHODS

 We conducted a retrospective, case control study of 80 pediatric patients with active hydrocephalus. The control group (a single step of preoperative skin antisepsis using povidone-iodine and isopropyl alcohol) comprised 40 patients who underwent a shunt surgery between January 2019 and June 2020 and the study group (two steps of preoperative skin antisepsis using 2% chlorhexidine gluconate in 70% isopropyl alcohol as a first step followed by povidone-iodine as a second step) comprised 40 patients who underwent a shunt surgery between July 2020 and January 2022.

RESULTS

 Shunt infection was encountered in 11 (13.7%) patients. It was significantly higher in preterm babies (p = 0.010), patients with a previous shunt revision (p < 0.001), and those with a previous shunt infection (p < 0.001). The incidence of infection was 22.5% in the control group and 5% in study group, with a statistically significant difference (p = 0.023).

CONCLUSIONS

 Two steps of preoperative skin antisepsis, first using chlorhexidine/alcohol and then povidone-iodine scrub solution, may significantly reduce the infection rate in pediatric VP shunt surgeries.

Decreased brain volume may be associated with the occurrence of peri-lead edema in Parkinson's disease patients with deep brain stimulation

BACKGROUND

Peri-lead edema (PLE) is a poorly understood complication of deep brain stimulation (DBS), which has been described in patients presenting occasionally with profound and often delayed symptoms with an incidence ranging from 0.4% up to even 100%. Therefore, our study aims to investigate the association of brain and brain compartment volumes on magnetic resonance imaging (MRI) with the occurrence of PLE in Parkinson's disease (PD) patients after DBS implantation in subthalamic nuclei (STN).

METHODS

This retrospective study included 125 consecutive PD patients who underwent STN DBS at the Department of Neurosurgery, Dubrava University Hospital from 2010 to 2022. Qualitative analysis was done on postoperative MRI T2-weighted sequence by two independent observers, marking PLE on midbrain, thalamus, and subcortical levels as mild, moderate, or severe. Quantitative volumetric analysis of brain and brain compartment volumes was conducted using an automated CIVET processing pipeline on preoperative MRI T1 MPRAGE sequences. In addition, observed PLE on individual hemispheres was delineated manually and measured using Analyze 14.0 software.

RESULTS

In our cohort, PLE was observed in 32.17%, mostly bilaterally. Mild PLE was observed in the majority of patients, regardless of the level observed. Age, sex, diabetes, hypertension, vascular disease, and the use of anticoagulant/antiplatelet therapy showed no significant association with the occurrence of PLE. Total grey matter volume showed a significant association with the PLE occurrence (r = -0.22, p = 0.04), as well as cortex volume (r = -0.32, p = 0.0005). Cortical volumes of hemispheres, overall hemisphere volumes, as well as hemisphere/total intracranial volume ratio showed significant association with the PLE occurrence. Furthermore, the volume of the cortex and total grey volume represent moderate indicators, while hemisphere volumes, cortical volumes of hemispheres, and hemisphere/total intracranial volume ratio represent mild to moderate indicators of possible PLE occurrence.

CONCLUSION

The results of our study suggest that the morphometric MRI measurements, as a useful tool, can provide relevant information about the structural status of the brain in patients with PD and represent moderate indicators of possible PLE occurrence. Identifying patients with greater brain atrophy, especially regarding grey matter before DBS implantation, will allow us to estimate the possible postoperative symptoms and intervene in a timely manner. Further studies are needed to confirm our findings and to investigate other potential predictors and risk factors of PLE occurrence.

Venous 3D Phase Contrast Magnetic Resonance Angiography Increases Diagnostic Certainty in Children with Ventriculoperitoneal Shunt and Suspected Shunt Failure

BACKGROUND

Clinical symptoms in children with suspected malfunction of ventriculoperitoneal shunt may not be specific and difficult to interpret. The presence or absence of ventricular enlargement on magnetic resonance imaging (MRI) does not reliably predict raised intracranial pressure (ICP) in these patients. Therefore, the aim was to investigate the diagnostic utility of 3D venous phase-contrast MR angiography (vPCA) in these patients.

MATERIALS

The MR studies of two groups of patients at two different examination dates were retrospectively analyzed; one group without clinical symptoms on both examinations and one with symptoms of shunt dysfunction on one examination receiving surgery. Both MRI examinations had to have been performed including axial T2 weighted (T2-w) images and 3D vPCA. Two (neuro)radiologists evaluated T2-w images alone and in combination with 3D vPCA in terms of suspected elevated ICP. Interrater reliability, sensitivity and specificity were assessed.

RESULTS

Compression of venous sinuses was seen significantly more often in patients with shunt failure (p = 0.00003). Consequently, evaluation of 3D vPCA and T2-w images increases sensitivity to 0.92/1.0 compared to T2-w images alone with 0.69/0.77, the interrater agreement for the diagnosis of shunt failure rises from κ = 0.71 to κ = 0.837. Concerning imaging markers, three groups could be identified in children with shunt failure.

CONCLUSION

In accordance with the literature, the results show that ventricular morphology alone is an unreliable marker for elevated ICP in children with shunt malfunction. The findings confirmed 3D vPCA as a valuable supplemental diagnostic tool improving diagnostic certainty for children with unchanged ventricular size in cases of shunt failure.

Odd presentation of shunt malfunction: a case series and review of literature

OBJECTIVE

Children with previous ventriculoperitoneal shunt (VPS) insertion due to hydrocephalus may refer to the hospital with various clinical complaints. Shunt malfunction is frequently diagnosed in these children necessitating shunt revision. Although increased head circumference, setting sun eye in younger children, and headache, nausea/vomiting, loss of consciousness, visual disturbance, and other signs of intracranial hypertension are common clinical manifestations of shunt malfunction, some patients may present with odd or unusual symptoms. Here, we present a series of patients with shunted hydrocephalus who presented with odd and unexpected clinical manifestations of shunt malfunction.

METHODS

Eight children with shunt malfunction were enrolled in this series. The age, sex, age of shunting, etiology of hydrocephalus and management, post-shunt insertion symptoms/sign, revision surgery, outcome, and follow-up were evaluated.

RESULTS

Patients were aged from 1 to 13 years (mean, 6.38 years). There were 5 males and 3 females. The odd presentation associated with shunt malfunction included facial palsy in three children, ptosis in 3 children, and torticollis and dystonia each in one child. All patients underwent shunt revision except for one patient in whom a new shunt was inserted. Follow-up showed improvement of the symptoms in all patients.

CONCLUSION

In this series, we reported eight patients with unusual signs and symptoms following shunt malfunction that were successfully diagnosed and managed.

Cerebrospinal Fluid Shunt Infections in Children: Do Hematologic and Cerebrospinal Fluid White Cells Examinations Correlate With the Type of Infection?

BACKGROUND

Cerebrospinal fluid (CSF) shunt infections in children represent an increasing problem in clinical practice. However, comprehensive clinical, laboratory and microbiologic data are scarce in pediatric age.

METHODS

We conducted a 10-year retrospective study to (1) analyze clinical, laboratory and microbiologic parameters associated with infections in children; (2) analyze results according to the type of catheter (medicated or not), type of infection (first or relapses), type of hydrocephalus (acquired and congenital), presence or not of bacteriemia; (3) describe antibiotic susceptibilities and their evolution during the study period.

RESULTS

Eighty-seven children with shunt infection and 61 children with mechanical shunt malfunction were enrolled. Fever, vomit, leukocytosis and elevated C-reactive protein were more frequent in the infected group (P < 0.001), while neurologic symptoms developed more frequently in the noninfected group (10.3% vs. 27.87%; P = 0.006). Local signs of inflammation and abdomen distension were similarly reported in the 2 groups. Children with medicated shunts had lower cell count in the CSF (12/mm3) compared with those with nonmedicated shunts (380/mm3; P < 0.0001). Gram-negative bacteria were more common in the not-medicated catheters (90.91% vs. 50% of cultures; P = 0.04). Gram-negative bacteria were identified in 50.67% of CSF cultures, Gram-positive bacteria in 53.33% and fungi were observed in 5.33%. Sixteen children (18.4%) had also a positive blood culture. Enterococci isolation was associated with relapsed infections (37.50% vs. 15.25%; P = 0.05).

CONCLUSIONS

Our study shows that the diagnosis and management of children with shunt infections are challenging. Prospective studies with a comprehensive approach focusing on patient, medical, microbiologic and surgical risk factors for first infection are urgently needed.

Positron Emission Tomography Scan: A Good Way to Untie the Gordian Knot of Infection in Case of Multiple Ventriculoperitoneal Shunts

Delayed infection from an implanted device can be challenging to diagnose. Here, we report a case of a 56-year-old male patient with history of congenital hydrocephalus and previous placement of a ventriculoperitoneal (VP) shunt who presented with sepsis without any evidence of shunt infection at follow-up 3 years after his most recent shunt implantation. The VP shunt contained 2 residual ventricular catheters and 2 residual peritoneal catheters, as the patient has had multiple VP shunt revisions since childhood. The patient was unresponsive to multiple antibiotic regimens. Of note, 2-[18]-fluoro-2-deoxy-D-glucose-positron emission tomography scan revealed hypermetabolism at the distal end of the latest implanted abdominal catheter without any abnormality of migrated cerebral catheters, highlighting the advantageous use of 2-[18]-fluoro-2-deoxy-D-glucose-positron emission tomography to identify the infected catheter when multiple devices are involved. Removal of abdominal catheters confirmed the localized infection, and follow-up was uneventful after shunt replacement.

Transient ventriculoperitoneal shunt malfunction in a pediatric patient: An illustrative case

Background:

Ventriculoperitoneal shunt (VPS), the mainstay of the treatment for hydrocephalus, is associated with relatively high revision rates. Transient hydrocephalus due to intermittent VPS obstruction should be recognized as a cause of VPS malfunction. While transient VPS dysfunction is well-recognized complication, there is a relative paucity of well-documented cases in the literature.

Case Description:

We present the case of a 4-year-old boy with a history of vascular malformation and hydrocephalus secondary to intraventricular hemorrhage. The patient presented with transient, self-resolving hydrocephalus (without intervention), as documented by clinical and radiological findings.

Conclusion:

Transient hydrocephalus due to intermittent VPS dysfunction in children is a rare entity, but it should be suspected in certain patients with VPS presenting with transient or self-improving symptoms.

Visual acuity loss and sixth nerve palsy as the only manifestations of slit ventricle syndrome

The case is presented of a girl diagnosed with obstructive hydrocephalus due to pilomyxoid astrocytoma, which required a ventriculoperitoneal shunt (VPS) at the age of 5 years and 10 months. Two months later, magnetic resonance imaging of the brain did not show ventriculomegaly or other signs of increased intracranial pressure. At the age of 6 years and 2 months, a rapid onset of bilateral visual acuity loss developed and she was diagnosed with slit ventricle syndrome. Despite valve revisions of the VPS, she developed an abrupt decline of visual acuity to hand motion at 10 cm. Fundus examination revealed bilateral optic atrophy. She did not report any other systemic symptoms suggesting increased intracranial pressure, such as headache, nausea, vomiting, lethargy, irritability, or altered levels of consciousness.

Ventriculoperitoneal shunt malfunction diagnosis based on substance dilution

OBJECTIVE

Current methods for the diagnosis of ventriculoperitoneal (VP) shunt malfunction lack specific standards; therefore, it may be missed or misdiagnosed. Hence, providing a reliable diagnostic method will help improve the accuracy of preoperative decision-making. Therefore, the aim of the study was to provide a new method for the diagnosis of VP shunt malfunction.

METHODS

After in vitro testing, we enrolled a total of 12 patients with VP shunt malfunction. Before revision surgery, 0.1 mL of a 5% sodium valproate (SV) solution was injected into the reservoir; 0.1 mL of the cerebrospinal fluid (CSF) was withdrawn 20 minutes later from the reservoir to measure the SV concentration. The process was repeated on the seventh day after surgery and compared with the preoperative results.

RESULTS

The mean ± standard deviation preoperative SV concentration in the cerebrospinal fluid was greater than the postoperative concentration (5967.8 ± 1281.3 vs 391.1 ± 184.6 μg/mL, P = .001).

CONCLUSION

The proposed method is a reliable, safe, and relatively simple alternative for the diagnosis of VP shunt malfunction and further provides a reference for treatment.

Neuroimaging for the Primary Care Provider: A Review of Modalities, Indications, and Pitfalls

When evaluating a child with a potential neurologic or neurodevelopmental disorder, identifying indications for imaging and the correct imaging modality to order can be challenging. This article provides an overview of computed tomography, MRI, ultrasonography, and radiography with an emphasis on indications for use, pitfalls to be avoided, and recent advances. A discussion of the appropriate use of ionizing radiation, intravenous contrast, and sedation is also provided.

Replacing Computed Tomography with "Rapid" Magnetic Resonance Imaging for Ventricular Shunt Imaging

Supplemental Digital Content is available in the text.

Introduction:

Children with ventricular shunts undergo frequent neuroimaging, and therefore, radiation exposures, to evaluate shunt malfunctions. The objective of this study was to safely reduce radiation exposure in this population by reducing computed tomography (CT) and increasing “rapid” magnetic resonance imaging (rMRI-shunt) among patients warranting neuroimaging for possible shunt malfunction.

Methods:

This was a single-center quality improvement study in a tertiary care pediatric emergency department (ED). We implemented a multidisciplinary guideline for ED shunt evaluation, which promoted the use of rMRI-shunt over CT. We included patients younger than 18 years undergoing an ED shunt evaluation during 11 months of the preintervention and 25 months of the intervention study periods. The primary outcome was the CT rate, and we evaluated the relevant process and balancing measures.

Results:

There were 266 encounters preintervention and 488 during the intervention periods with similar neuroimaging rates (80.7% versus 81.5%, P = 0.8.) CT decreased from 90.1% to 34.8% (difference −55.3%, 95% confidence interval [CI]: −71.1, −25.8), and rMRI-shunt increased from 9.9% to 65.2% (difference 55.3%, 95% CI: 25.8, 71.1) during the preintervention and intervention periods, respectively. There were increases in the mean time to neuroimaging (53.1 min; [95% CI: 41.6, 64.6]) and ED length of stay (LOS) (52.3 min; [95% CI: 36.8, 67.6]), without changes in total neuroimaging, 72-hour revisits, or follow-up neuroimaging.

Conclusions:

Multidisciplinary implementation of a standardized guideline reduced CT and increased rMRI-shunt use in a pediatric ED setting. Clinicians should balance the reduction in radiation exposure with ED rMRI-shunt for patients with ventricular shunts against the increased time of obtaining imaging and LOS.

OS reboot

Cerebrospinal fluid (CSF) diversion or shunting procedures are the most commonly performed surgery for the treatment of hydrocephalus and are often employed in the management of elevated intracranial pressure due to a variety of diseases. Despite their popularity however, approximately 50% of shunts fail within the first two years, and several revisions are required within the first decade after placement. Ophthalmologists may encounter patients with a CSF shunt to evaluate for concerns of vision loss or diplopia and to determine if papilledema is present. We discuss the neuro-ophthalmic manifestations and evaluation of possible CSF shunt malfunction.

Visual acuity loss and sixth nerve palsy as the only manifestations of slit ventricle syndrome

The case is presented of a girl diagnosed with obstructive hydrocephalus due to pilomyxoid astrocytoma, which required a ventriculoperitoneal shunt (VPS) at the age of 5 years and 10 months. Two months later, magnetic resonance imaging of the brain did not show ventriculomegaly or other signs of increased intracranial pressure. At the age of 6 years and 2 months, a rapid onset of bilateral visual acuity loss developed and she was diagnosed with slit ventricle syndrome. Despite valve revisions of the VPS, she developed an abrupt decline of visual acuity to hand motion at 10cm. Fundus examination revealed bilateral optic atrophy. She did not report any other systemic symptoms suggesting increased intracranial pressure, such as headache, nausea, vomiting, lethargy, irritability, or altered levels of consciousness.

Management of Hydrocephalus in Children: Anatomic Imaging Appearances of CSF Shunts and Their Complications

OBJECTIVE. This article addresses the management of hydrocephalus and the CSF shunts used to treat this entity. CONCLUSION. CSF shunts have a high failure rate. Imaging plays a pivotal role in assessing CSF shunt failure and determining the need for surgical revision. An in-depth knowledge of CSF shunt components, their failure modes, and the corresponding findings on anatomic imaging studies is necessary to ensure timely diagnosis and prevent permanent neurologic damage.

Role of aquaporins in hydrocephalus: what do we know and where do we stand? A systematic review

INTRODUCTION

Glymphatic fluid circulation may be considered the lymphatic system of the brain and the main role of such system seems to be played by aquaporins (AQPs), a family of proteins which regulates water exchange, in particular AQP4 and 1. Alterations of glymphatic fluid circulation through AQPs variations are now emerging as central elements in the pathophysiology of different brain conditions, like hydrocephalus. This systematic review provides an insight about the role of AQPs in hydrocephalus establishment and compensation, investigating their possible role as diagnostic tools or therapeutic targets.

METHODS

PubMed database was screened searching for the relevant existing literature in English language published until February 29th 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

RESULTS

A total of 40 articles met the inclusion criteria for our systematic analysis. AQP4 resulted the most studied water channel, followed by AQP1. The changes in cerebrospinal fluid (CSF), brain parenchyma and choroid plexus (CP) in different hydrocephalus type were analyzed. Moreover, important pharmacological interactions regarding AQP and molecules or conditions were discussed. A very interesting result is the general consensus on increase of AQP4 in hydrocephalic patients, unless in patients suffering from idiopathic normal pressure hydrocephalus, where AQP4 shows a tendency in reduction.

CONCLUSION

AQP seem to play a central role in the pathophysiology of hydrocephalus and in its compensation mechanisms. Further studies are required to definitively establish their precise roles and their quantitative changes to allow their utilization as diagnostic tools or therapeutic targets.

National Imaging Trends in Pediatric Traumatic Brain Injury and Hydrocephalus

OBJECTIVE

Reduction in use of computed tomography (CT) in favor of rapid-sequence magnetic resonance imaging (MRI) to decrease pediatric radiation exposure has varied across institutions in the United States. The aims of this study were to understand national trends in CT and rapid-sequence MRI usage and identify variables affecting imaging practices and obstacles to CT reduction.

METHODS

This was a retrospective review of deidentified discharge data for children with hydrocephalus and traumatic brain injury (TBI) in the Healthcare Cost and Utilization Project Kids' Inpatient Database in 2000, 2003, 2006, 2009, 2012, and 2016. Utilization of MRI without contrast and CT was extracted using International Classification of Diseases, Ninth Revision, and International Classification of Diseases, Tenth Revision, codes. Hospital region and age cohorts were extracted and used to categorize data. χ2 tests and logistic regression were used for analysis.

RESULTS

Hospitalizations utilizing CT decreased (P < 0.05) and hospitalizations utilizing MRI increased (P < 0.05) overall in both diagnosis groups throughout the years analyzed. However, there was significant regional variation in imaging. The Northeast had higher CT rates (P < 0.05) and the South had lower CT rates in patients with hydrocephalus and TBI (P < 0.05). No regional variation was found for rates of MRI use in patients with TBI.

CONCLUSIONS

Nationwide, the average number of discharges after hospitalizations utilizing CT in patients with hydrocephalus and TBI has decreased, while discharges after hospitalizations utilizing MRI as an alternative imaging modality have increased. Despite successful overall CT reduction, significant regional variation exists within this trend showing inconsistent reduction of CT use.

Diagnostic Accuracy of Non-Invasive Thermal Evaluation of Ventriculoperitoneal Shunt Flow in Shunt Malfunction: A Prospective, Multi-Site, Operator-Blinded Study

BACKGROUND

Thermal flow evaluation (TFE) is a non-invasive method to assess ventriculoperitoneal shunt function. Flow detected by TFE is a negative predictor of the need for revision surgery. Further optimization of testing protocols, evaluation in multiple centers, and integration with clinical and imaging impressions prompted the current study.

OBJECTIVE

To compare the diagnostic accuracy of 2 TFE protocols, with micropumper (TFE+MP) or without (TFE-only), to neuro-imaging in patients emergently presenting with symptoms concerning for shunt malfunction.

METHODS

We performed a prospective multicenter operator-blinded trial of a consecutive series of patients who underwent evaluation for shunt malfunction. TFE was performed, and preimaging clinician impressions and imaging results were recorded. The primary outcome was shunt obstruction requiring neurosurgical revision within 7 d. Non-inferiority of the sensitivity of TFE vs neuro-imaging for detecting shunt obstruction was tested using a prospectively determined a priori margin of −2.5%.

RESULTS

We enrolled 406 patients at 10 centers. Of these, 68/348 (20%) evaluated with TFE+MP and 30/215 (14%) with TFE-only had shunt obstruction. The sensitivity for detecting obstruction was 100% (95% CI: 88%-100%) for TFE-only, 90% (95% CI: 80%-96%) for TFE+MP, 76% (95% CI: 65%-86%) for imaging in TFE+MP cohort, and 77% (95% CI: 58%-90%) for imaging in the TFE-only cohort. Difference in sensitivities between TFE methods and imaging did not exceed the non-inferiority margin.

CONCLUSION

TFE is non-inferior to imaging in ruling out shunt malfunction and may help avoid imaging and other steps. For this purpose, TFE only is favored over TFE+MP.

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

BACKGROUND

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.

Diagnosis of Ventriculoperitoneal Shunt Malfunction: A Practical Algorithm

OBJECTIVE

This study aims to present a practical method to accurately diagnose ventriculoperitoneal shunt (VPS) malfunction and to detect the exact level at which the system has failed to tailor VPS revision at that level only.

METHODS

A tertiary referral single-center algorithm for diagnosis of VPS malfunction is proposed. Based on clinical symptoms and confirmed ventricular dilatation on computed tomography, the VPS reservoir is punctured; if no cerebrospinal fluid is obtained, ventricular catheter replacement is recommended. Conversely, if cerebrospinal fluid is obtained, a sample is sent for cultural examination and the macroscopic integrity of the whole system is checked via plain radiography in the angiographic suite. Then, through the injection of iodate contrast medium into the reservoir and selective exclusion of the proximal and distal catheters, the patency and correct VPS functioning are investigated.

RESULTS

A total of 102 (56 males) patients (mean age, 41.5 years; range, 1-86 years) underwent a VPS function test from 2012 to 2018: 59 cases of VPS malfunction (57.8%) were diagnosed. Ventricular catheter obstruction/damage/displacement occurred in 12/59 patients (20.3%), valve damage in 11/59 patients (18.6%), distal catheter obstruction/damage/displacement in 17/59 patients (28.8%) and 2-level (valve/proximal catheter or valve/distal catheter) obstruction/damage/displacement in 16/59 patients (27.1%). Subclinical infection was diagnosed in 3 patients (5.1%). VPS revision was performed selectively at the level of failure.

CONCLUSIONS

The proposed algorithm is a practical, simple and minimally invasive technique to accurately diagnose VPS malfunction, identifying the exact level of system failure and allowing surgical VPS revision to be tailored, avoiding unnecessary complete system replacement.

Refractory epilepsy associated with ventriculoperitoneal shunt over-drainage: case report

Epilepsy and intracranial pressure (ICP) can be interrelated. While shunt malfunction is recognized as a cause of seizures, shunt over-drainage is seldom reported as such. We report a child who had undergone ventriculoperitoneal shunt insertion at the age of 6 months following an excision of a left ventricle choroid plexus papilloma, who developed refractory epilepsy since the age of 3 years. An MRI showed small ventricles. The child presented with acute hydrocephalus due to proximal shunt malfunction at the age of 11 years and was treated with an endoscopic third ventriculostomy. Following the procedure, the seizures abated. Our case suggests that intractable epilepsy may be related to intracranial hypotension. Potential treatments for shunt over-drainage may be indicated even in the absence of classic over-drainage symptoms, in the presence of refractory epilepsy.

Tales from the Night:: Emergency MR Imaging in Pediatric Patients after Hours

Overnight in-house radiology has rapidly become an important part of contemporary practice models, and is increasingly the norm in pediatric radiology. MR imaging is an indispensable first-line and problem-solving tool in the pediatric population. This has led to increasingly complex MR imaging being performed "after hours" on pediatric patients. This article reviews the factors that have led to widespread overnight subspecialty radiology and the associated challenges for overnight radiologists, and provides an overview of up-to-date imaging techniques and imaging findings of the most common indications for emergent MR imaging in the pediatric population.

The value of CSF flow studies in the management of CSF disorders in children: a pictorial review

CSF flow disorders are frequently encountered in children. The advent of MR technology with the emergence of new pulse sequences allowed better understanding of CSF flow dynamics. In this pictorial review, we aim to conduct a comprehensive review of the MR protocol used to study CSF flow disorders and to discuss the utility of each pulse sequence in the adopted protocol. We will focus on the key anatomical structures that should be examined to differentiate hydrocephalus form ventricular dilatation ex-vacuo. The MR features of obstructive and communicating hydrocephalus will be discussed, in addition to the manifestations of CSF disorders associated with posterior fossa malformations (Dandy-Walker malformation, Chiari, and Blake's pouch cyst). Moreover, the value of MRI in the assessment of patients following interventional procedures (ventriculoperitoneal shunt and third ventriculostomy) will be addressed.

Shunt Devices for Neurointensivists: Complications and Management

Cerebrospinal fluid diversion has become the mainstay treatment in hydrocephalus for over 50 years. As the number of patients with ventricular shunt systems increases, neurointensivists are becoming the first-line physicians for many of these patients. When symptoms of a shunt malfunction are suspected and access to a neurosurgeon is limited or delayed, workup and temporizing measures must be initiated. The article highlights the functional nuances, complications, and management of current programmable shunt valves and their MRI sensitivity.

Two signs indicative of successful access in nuclear medicine cerebrospinal fluid diversionary shunt studies

BACKGROUND

Successful shunt access is the first step in a properly performed nuclear medicine cerebrospinal fluid (CSF) shunt study.

OBJECTIVE

To determine the significance of the radiotracer configuration at the injection site during initial nuclear medicine CSF shunt imaging and the lack of early systemic radiotracer activity as predictors of successful shunt access.

MATERIALS AND METHODS

With Institutional Review Board approval, three nuclear medicine physicians performed a retrospective review of all consecutive CSF shunt studies performed in children at our institution in 2015. Antecedent nuclear medicine CSF shunt studies in these patients were also assessed and included in the review. The appearance of the reservoir site immediately after radiotracer injection was classified as either figure-of-eight or round/ovoid configuration. The presence or absence of early systemic distribution of the tracer on the 5-min static images was noted and separately evaluated.

RESULTS

A total of 98 nuclear medicine ventriculoperitoneal CSF shunt studies were evaluated. Figure-of-eight configuration was identified in 87% of studies and, when present, had 93% sensitivity, 78% specificity, 92% accuracy, 98% positive predictive value (PPV) and 54% negative predictive value (NPV) as a predictor of successful shunt access. Early systemic activity was absent in 89 of 98 studies. Lack of early systemic distribution of the radiotracer had 98% sensitivity, 78% specificity, 96% accuracy, 98% PPV and 78% NPV as a predictor of successful shunt access. Figure-of-eight configuration in conjunction with the absence of early systemic tracer activity had 99% PPV for successful shunt access.

CONCLUSION

Figure-of-eight configuration at the injection site or lack of early systemic radiotracer activity had moderate specificity for successful shunt access. Specificity and PPV significantly improved when both signs were combined in assessment.

Common and Uncommon Causes of Ventriculoperitoneal Shunt Malfunction Diagnosed on Plain Radiographs

Thousands of patients with hydrocephalus are treated successfully with ventriculoperitoneal shunts. Ventriculoperitoneal shunts are known to have high malfunction rates, most of which are owing to mechanical causes. When shunt malfunction is suspected, shunt series are often performed to evaluate the mechanical causes of malfunction. These initial radiographs have proven critical in guiding subsequent management. This article is designed to review the various causes of shunt malfunction that can be diagnosed with radiographs.

Migration of the distal catheter of the ventriculoperitoneal shunt in hydrocephalus: A Comprehensive Analytical Review from an Anatomical Perspective

There have been many reports on migration of the distal catheter of the ventriculoperitoneal shunt (VPS) since this phenomenon was recognized 50 years ago. However, there have been no attempts to analyze its different patterns or to assess these patterns in terms of potential risk to patients. We comprehensively reviewed all reports of distal VPS catheter migration indexed in PubMed and identified three different anatomical patterns of migration based on catheter extension and organs involved: (1) internal, when the catheter invades any viscus inside the thoracic, abdominal, or pelvic cavity; (2) external, when the catheter penetrates through the body wall either incompletely (subcutaneously) or completely (outside the body); and (3) compound, when the catheter penetrates a hollow viscus and protrudes through a pre-existing anatomical orifice. We also analyzed the association between each migration type and several key factors. External migration occurred mostly in infants. In contrast, internal migration occurred mostly in adults. A body wall weakness was not a risk factor for catheter protrusion. Shunt duration was a critical factor in the migration pattern, as most newly-replaced shunts tended to migrate externally. Clinicians must pay close attention to cases of large bowel perforation, since they were most often associated with intracranial infections. The organ involved in compound migration could determine the route of extrusion, as the bowel was involved in all trans-anal migrations and the stomach in most trans-oral cases. Clin. Anat. 30:821-830, 2017. © 2017Wiley Periodicals, Inc.

Predictors of Ventriculoperitoneal Shunt Failure in Children Undergoing Initial Placement or Revision

BACKGROUND

Ventriculoperitoneal (VP) shunt placement, the mainstay of treatment for hydrocephalus, can place a substantial burden on patients and health care systems because of high complication and revision rates. We aimed to identify factors associated with 30-day VP shunt failure in children undergoing either initial placement or revision.

METHODS

VP shunt placements performed on patients in the 2012-2013 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Pediatric were identified.

RESULTS

VP shunts were placed in 3,984 patients either as an initial placement (n = 1,093) or as a revision (n = 2,891). Compared to the initial-placement group, the revision group was significantly more likely to experience shunt failure (14 vs. 8%, p < 0.0001). In the initial-placement group, congenital hydrocephalus was independently associated with shunt failure (OR 1.83; 95% CI 1.01-3.31, p = 0.047). In the revision group, cardiac risk factors (OR 1.38; 95% CI 1.00-1.90, p = 0.047), a chronic history of seizures (OR 1.33; 95% CI 1.04-1.71, p = 0.022), and a history of neuromuscular disease (OR 0.61; 95% CI 0.41-0.90, p = 0.014) were independently associated with shunt failure.

CONCLUSIONS

Identifying the factors associated with VP shunt failure may allow the development of interventions to decrease failures. Further refinement of the collected variables in the NSQIP Pediatric specific to neurosurgical procedures is necessary to identify modifiable risk factors.

An improved reservoir for the flushing test to diagnose shunt insufficiency

OBJECTIVE Reservoirs integrated into hydrocephalus shunts are commonly used for the removal of CSF and for intra-ventricular pressure measurement. Pumping with the reservoir to diagnose shunt sufficiency is still a matter of controversy. The authors describe an improved flushing device and its characteristic features in vitro and in vivo. METHODS The flushing reservoir is constructed with a sapphire ball in a cage as a nonresistance valve to also enable the detection of distal occlusions. The most important reservoir parameters were investigated in vitro, simulating total and partial proximal and distal shunt occlusions. Then the expected advantages were assessed in vivo by evaluating the pump test data of 360 implanted reservoirs. The results were compared with those found in the literature. RESULTS The optimization of the technical parameters of the device, such as the high stroke volume in combination with moderate suction force, are obvious advantages compared with other flushing devices. Total occlusion of the ventricular catheter and the valve could be assessed with high certainty. The detection of a total obstruction of the peritoneal catheter or any partial obstruction is also possible, depending on its exact grade and location. CONCLUSIONS Shunt obstructions can be assessed using the pumping test. The reservoir construction presented here provides a clear enhancement of that diagnostic test.

Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children

BACKGROUND

Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection.

METHODS

CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients.

RESULTS

Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection.

CONCLUSION

Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection.

FUNDING

This work was supported in part by the Impact Fund of Children's of Alabama.

Incisional Hernia Following Ventriculoperitoneal Shunt Positioning

Incisional hernia represents a rare complication after ventriculoperitoneal shunt positioning due to failure of the fascial suture in the site of abdominal entrance of ventriculoperitoneal catheter. Clinical presentation can be extremely variable, according to patient's performance status, herniated material constitution (i.e. mesenteric fat, bowel loops or both) and complication occurrence (e.g. strangulation or intestinal obstruction). Early diagnosis is fundamental in order to surgically repair the defect and prevent further complications. We present the case of a paucisymptomatic incisional hernia following ventriculoperitoneal shunt positioning. Diagnosis was made by means of ultrasound and confirmed by means of computed tomography. The patient was successfully managed by means of surgical repositioning of herniated loop and re-suture.

A Case of Discontinued Proximal Limb of a Ventriculoperitoneal Shunt With Patent Fibrous Tract

Radionuclide shuntogram is important in the evaluation of cerebrospinal fluid (CSF) shunts complications such as mechanical failure, malpositioning, pseudocyst, or overdrainage. We present here a case of congenital hydrocephalus and posterior fossa cyst with multiple shunt procedures and revisions with breakage of the proximal tube of the ventriculoperitoneal shunt but preserved CSF drainage through the patent fibrous tract. Careful correlation with SPECT/CT images helped confirm the breakage and exclude CSF leak outside of the tract, which was suspected on planar images.

Indications for the performance of neuroimaging in children

Pediatric neurology relies on ultrasound, computed tomography (CT), and magnetic resonance (MR) imaging. CT prevails in acute neurologic presentations, including traumatic brain injury (TBI), nontraumatic coma, stroke, and status epilepticus, because of easy availability, with images of diagnostic quality, e.g., to exclude hemorrhage, usually completed quickly enough to avoid sedation. Concerns over the risks of ionizing radiation mean re-imaging and higher-dose procedures, e.g., arteriography and venography, require justification. T1/T2-weighted imaging (T1/T2-WI) MR with additional sequences (arteriography, venography, T2*, spectroscopy, diffusion tensor, perfusion, diffusion- (DWI) and susceptibility-weighted imaging (SWI)) often clarifies the diagnosis, which may alter management in acute settings, as well as chronic conditions, e.g., epilepsy. Clinical acumen remains essential to avoid imaging, e.g., in genetic epilepsies or migrainous headaches responding to treatment, or to target sequences to specific diagnosis, e.g., T1/T2-WI for shunt dysfunction (with SWI for TBI); DWI, arteriography including neck vessels, and venography for acute hemiplegia or coma; coronal temporal cuts for partial epilepsy; or muscle imaging for motor delay. The risk of general anesthesia is low; "head-only" scanners may allow rapid MRI without sedation. Timely and accurate reporting, with discrepancy discussion between expert neuroradiologists, is important for management of the child and the family's expectations.

[Semiology of ventriculoperitoneal shunting dysfunction in children - a review]

INTRODUCTION

Ventriculoperitoneal shunting (VPS) is a treatment of the hydrocephalus that may dysfunction. The clinical presentation of shunt dysfunction is variable. We therefore decided to focus on the clinical presentation of VPS malfunction in children, as this condition requires immediate emergency treatment and because of the sometimes confusing signs of intracranial hypertension in a shunted child.

MATERIALS AND METHODS

We searched PubMed with the following groups of keywords: (dysfunction OR blockage) AND shunting AND hydrocephalus; shunt complications AND hydrocephalus; hydrocephalus AND shunt AND malfunction. Articles dealing with ventriculo-atrial shunt were excluded. A total of 79 articles were retained for analysis (English and French). Case reports were excluded.

RESULTS

The clinical presentation varies by age: vomiting and alterated level of consciousness are the most frequent signs in older children, whereas infants present more often with raised intracranial pressure symptoms such as nausea, vomiting, irritability and bulging fontanel. Drowsiness is a good predictor of VPS dysfunction. An asymptomatic presentation is rare but possible. Abdominal presentation is also possible, ranging from abdominal discomfort to peritonitis. Fever, occurring a short time after the last intervention, and irritability are good predictors of shunt infection. Pumping the chamber of the VPS has a weak positive predictive value (12%). Shunt dysfunction can lead to death, with an estimated mortality rate at 1% per year during the first years.

CONCLUSION

It is essential to be aware of the variability of the clinical presentation of VPS dysfunction, because of the potential severity of this condition. Also it is important to pay attention to the comments of the parents, especially if the child experienced a previous shunt malfunction.

Utility of computed tomography or magnetic resonance imaging evaluation of ventricular morphology in suspected cerebrospinal fluid shunt malfunction

OBJECT

It is common to evaluate children with suspected CSF shunt malfunctions using CT of the head or, more recently, "quick brain" MRI. However, the reliability of using ventricular behavior, as assessed on cranial imaging during previous presentations with shunt obstructions, is not well defined. The authors conducted a study to determine if CT or MRI of ventricular morphology added useful clinical information in the evaluation of shunt malfunctions.

METHODS

A retrospective chart review of children operated on at Texas Children's Hospital from February 20, 2011, to June 18, 2013, for shunt obstruction was conducted. Inclusion criteria involved age 3 years or older in patients who had undergone two or more shunt revisions for intraoperatively confirmed obstructions. Patients with shunt infection but without shunt obstruction and patients with fourth ventricular shunt failure were excluded from the study. Preoperative CT or MRI results were dichotomized into two distinct categories, as determined by a radiologist's report: either dilation of the ventricular system in comparison with prior scans at points the shunt was deemed functional, or no dilation of the ventricular system in comparison such scans. Determination of the presence of shunt obstruction was assessed by findings documented by the surgeon in the operative report. Each case was then analyzed to see if the patient has a reliable pattern of ventricular dilation, or no dilation, at times of shunt obstruction.

RESULTS

Forty-two patients (25 males and 17 females) were included in the study. There were a total of 117 patient encounters analyzed and an average of 2.79 encounters per patient. The mean age at shunt failure presentation was 10.8 years (range 3-23 years). In 4 encounters, patients presented with a CSF leak or pseudomeningocele. Twenty-seven patients (64%) consistently demonstrated dilation of the ventricular system during episodes of shunt obstruction. Four patients (10%) consistently demonstrated no dilation during episodes of shunt obstruction. Eleven patients (26%) demonstrated inconsistent changes in ventricular size at times of shunt obstruction. In those first patient encounters with shunt obstruction presenting with ventricular dilation, 92% (49 of 53) of subsequent encounters demonstrated ventricular dilation with shunt obstruction presentations.

CONCLUSIONS

Historical CT or MRI data regarding ventricular morphology patterns seen during prior examinations of shunt obstructions may inform a clinician's judgment of shunt obstruction on subsequent presentations, but they are not conclusive. In the present series, the authors found that changes in the morphology of a given patient's ventricular system when shunt obstruction occurs were often consistent and predictable, but not always. It remains imperative, however, that cranial images obtained to rule out shunt malfunction be compared with prior studies.

Techniques that decrease or eliminate ionizing radiation for evaluation of ventricular shunts in children with hydrocephalus

Shunted hydrocephalus in children is a commonly seen diagnosis in hospitals throughout the world and is one of the most common chronic pediatric neurosurgical conditions. These children undergo numerous studies for routine surveillance as well as for evaluation of shunt malfunction, many of which are associated with significant radiation exposure over the child׳s lifetime. It is in the child׳s best interest to minimize the overall exposure to ionizing radiation so as to decrease the chance of the deleterious effects from occurring. The article outlines the epidemiology of ventricular shunt catheters, the typical indications and methods for shunt evaluation, and the preferred alternative imaging methods that eliminate or reduce radiation exposure.

Imaging evaluation of CSF shunts

OBJECTIVE

The objective of this article is to describe an approach to imaging CSF shunts. Topics reviewed include the components and imaging appearances of the most common types of shunts and the utility of different imaging modalities for the evaluation of shunt failure. Complications discussed include mechanical failure, infection, ventricular loculation, overdrainage, and unique complications related to each shunt type.

CONCLUSION

This article reviews the imaging features of common CSF shunts and related complications with which radiologists should be familiar.

Scout view in pediatric CT neuroradiological evaluation: do not underestimate!

PURPOSE

Computed tomography (CT) is an important first-line imaging tool in pediatric neuroradiology. The scout view (SV) is essential for planning the CT study. It is frequently underestimated for its diagnostic value but may harbor important diagnostic clues. We present and discuss the role of SV in the accurate interpretation of pediatric neuroradiological CT studies.

METHODS

CT studies have been collected over 12 months by an experienced pediatric neuroradiologist. Retrospective evaluation of SV and axial CT images was performed in nine children, where the SV gave important diagnostic information. Abnormalities on SV were classified as (1) located outside the field of view as imaged by the cross-sectional CT slices or (2) located in the plane of the cross-sectional CT slices or orthogonal to it.

RESULTS

Five male and four female patients were included. The mean age at CT was 9.86 years (range, 0.75 to 19 years). Abnormalities on SV were located outside of the field of view as imaged by cross-sectional CT slices in six out of nine children and were within the plane of the CT slices or orthogonal to it in three out of nine children.

CONCLUSIONS

A thorough and accurate evaluation of the SV may add valuable, clinically relevant information and should be a routine part of the interpretation of each pediatric neuroradiological CT study.