Failure of cerebrospinal fluid shunts: part II: overdrainage, loculation, and abdominal complications

Cerebrospinal Fluid Shunt Infections

Cerebrospinal fluid (CSF) shunt infections are a particularly challenging clinical problem. This review article addresses epidemiology and microbiology of CSF shunt infections. Clinical care is reviewed in detail, including recent guidelines and systematic review articles. Finally, current research into prevention and treatment is highlighted, with a discussion on the mechanisms of infection.

Green Solid Lipid Nanoparticles by Fatty Acid Coacervation: An Innovative Nasal Delivery Tool for Drugs Targeting Cerebrovascular and Neurological Diseases

Cerebrovascular and neurological diseases are characterized by neuroinflammation, which alters the neurovascular unit, whose interaction with the choroid plexus is critical for maintaining brain homeostasis and producing cerebrospinal fluid. Dysfunctions in such process can lead to conditions such as idiopathic normal pressure hydrocephalus, a common disease in older adults. Potential pharmacological treatments, based upon intranasal administration, are worthy of investigation because they might improve symptoms and avoid surgery by overcoming the blood-brain barrier and avoiding hepatic metabolism. Nasal lipid nanocarriers, such as solid lipid nanoparticles, may increase the nasal retention and permeation of drugs. To this aim, green solid lipid nanoparticles, obtained by coacervation from natural soaps, are promising vehicles due to their specific lipid matrix composition and the unsaponifiable fraction, endowed with antioxidant and anti-inflammatory properties, and thus suitable for restoring the neurovascular unit function. In this experimental work, such green solid lipid nanoparticles, fully characterized from a physico-chemical standpoint, were loaded with a drug combination suitable for reverting hydrocephalus symptoms, allowing us to obtain a non-toxic formulation, a reduction in the production of the cerebrospinal fluid in vitro, and a vasoprotective effect on an isolated vessel model. The pharmacokinetics and biodistribution of fluorescently labelled nanoparticles were also tested in animal models.

Measuring CSF shunt flow with MRI using flow enhancement of signal intensity (FENSI)

PURPOSE

To develop and validate a noninvasive imaging technique for accurately assessing very slow CSF flow within shunt tubes in pediatric patients with hydrocephalus, aiming to identify obstructions that might impede CSF drainage.

THEORY AND METHODS

A simulation of shunt flow enhancement of signal intensity (shunt-FENSI) signal is used to establish the relationship between signal change and flow rate. The quantification of flow enhancement of signal intensity data involves normalization, curve fitting, and calibration to match simulated data. Additionally, a phase sweep method is introduced to accommodate the impact of magnetic field inhomogeneity on the flow measurement. The method is tested in flow phantoms, healthy adults, intensive care unit patients with external ventricular drains (EVD), and shunt patients. EVDs enable shunt-flow measurements to be acquired with a ground truth measure of CSF drainage.

RESULTS

The flow-rate-to-signal simulation establishes signal-flow relationships and takes into account the T1 of draining fluid. The phase sweep method accurately accounts for phase accumulation due to frequency offsets at the shunt. Results in phantom and healthy human participants reveal reliable quantification of flow rates using controlled flows and agreement with the flow simulation. EVD patients display reliable measures of flow rates. Shunt patient results demonstrate feasibility of the method and consistent flow rates for functional shunts.

CONCLUSION

The results demonstrate the technique's applicability, accuracy, and potential for diagnosing and noninvasively monitoring hydrocephalus. Limitations of the current approach include a high sensitivity to motion and strict requirement of imaging slice prescription.

Prospects of CSF shunt independence among chronically shunted patients

BACKGROUND AND OBJECTIVES

CSF shunt placement for hydrocephalus and other etiologies has arguably been the most life-saving intervention in pediatric neurosurgery in the past 6 decades. Yet, chronic shunting remains a source of morbidity for patients of all ages. Neuroendoscopic surgery has made shunt independence possible for newly diagnosed hydrocephalic patients. In this study, we examine the prospects of shunt independence with or without endoscopic third ventriculostomy (ETV) in chronically shunted patients.

METHODS

After IRB approval, a retrospective analysis was completed on patients whose shunt was ligated or removed to achieve shunt independence, with or without ETV. Clinical and imaging data were collected.

RESULTS

Eighty-eight patients with CSF shunts had their shunt either ligated or removed, 57 of whom had a concomitant ETV. Original reasons for shunting included: congenital hydrocephalus 20 (23%), post-hemorrhagic hydrocephalus (PHH) of prematurity 14 (16%), aqueductal stenosis 10 (11%), intracranial cyst 8 (9%), tumor 8 (9%), infantile subdural hematomas 8 (9%), myelomeningocele 7 (8%), post-traumatic hydrocephalus 7 (8%) and post-infectious hydrocephalus 6 (7%). The decision to perform a simultaneous ETV was made based on etiology. Forty-nine (56%) patients became shunt independent. The success rate was 46% in the ETV group and 73% in the no ETV group. Using multivariate analysis and Cox Proportional Hazards models, age > 4 months at shunt placement (p = 0.032), no shunt revisions (p = 0.01), select etiologies (p = 0.043), and ETVSS > 70 (in the ETV group) (p = 0.017), were protective factors for shunt independence.

CONCLUSION

Considering the long-term complications of shunting, achieving shunt independence may provide hope for improved quality of life. While this study is underpowered, it provides pilot data identifying factors that predict shunt independence in chronically shunted patients, namely age, absence of prior shunt revision, etiology, and in the ETV group, the ETVSS.

Antibiotic impregnated catheters and intrathecal antibiotics for CSF shunt infection prevention in children undergoing low-risk CSF shunt surgery

BACKGROUND

Cerebrospinal fluid (CSF) shunts allow children with hydrocephalus to survive and avoid brain injury (J Neurosurg 107:345-57, 2007; Childs Nerv Syst 12:192-9, 1996). The Hydrocephalus Clinical Research Network implemented non-randomized quality improvement protocols that were shown to decrease infection rates compared to pre-operative prophylactic intravenous antibiotics alone (standard care): initially with intrathecal (IT) antibiotics between 2007-2009 (J Neurosurg Pediatr 8:22-9, 2011), followed by antibiotic impregnated catheters (AIC) in 2012-2013 (J Neurosurg Pediatr 17:391-6, 2016). No large scale studies have compared infection prevention between the techniques in children. Our objectives were to compare the risk of infection following the use of IT antibiotics, AIC, and standard care during low-risk CSF shunt surgery (i.e., initial CSF shunt placement and revisions) in children.

METHODS

A retrospective observational cohort study at 6 tertiary care children's hospitals was conducted using Pediatric Health Information System + (PHIS +) data augmented with manual chart review. The study population included children ≤ 18 years who underwent initial shunt placement between 01/2007 and 12/2012. Infection and subsequent CSF shunt surgery data were collected through 12/2015. Propensity score adjustment for regression analysis was developed based on site, procedure type, and year; surgeon was treated as a random effect.

RESULTS

A total of 1723 children underwent initial shunt placement between 2007-2012, with 1371 subsequent shunt revisions and 138 shunt infections. Propensity adjusted regression demonstrated no statistically significant difference in odds of shunt infection between IT antibiotics (OR 1.22, 95% CI 0.82-1.81, p = 0.3) and AICs (OR 0.91, 95% CI 0.56-1.49, p = 0.7) compared to standard care.

CONCLUSION

In a large, observational multicenter cohort, IT antibiotics and AICs do not confer a statistically significant risk reduction compared to standard care for pediatric patients undergoing low-risk (i.e., initial or revision) shunt surgeries.

Toward the "Perfect" Shunt: Historical Vignette, Current Efforts, and Future Directions

As a concept, drainage of excess fluid volume in the cranium has been around for more than 1000 years. Starting with the original decompression-trepanation of Abulcasis to modern programmable shunt systems, to other nonshunt-based treatments such as endoscopic third ventriculostomy and choroid plexus cauterization, we have come far as a field. However, there are still fundamental limitations that shunts have yet to overcome: namely posture-induced over- and underdrainage, the continual need for valve opening pressure especially in pediatric cases, and the failure to reinstall physiologic intracranial pressure dynamics. However, there are groups worldwide, in the clinic, in industry, and in academia, that are trying to ameliorate the current state of the technology within hydrocephalus treatment. This chapter aims to provide a historical overview of hydrocephalus, current challenges in shunt design, what members of the community have done and continue to do to address these challenges, and finally, a definition of the "perfect" shunt is provided and how the authors are working toward it.

EEG Correlates of Spikes in Intracranial Pressure Caused by Transient Ventriculoperitoneal Shunt Malfunction

SUMMARY

A 30-year-old man with recurrent headaches and seizure-like activity and a 26-year-old woman with worsening headaches were admitted to the hospital. Both had ventriculoperitoneal shunts and history of several shunt revisions for congenital hydrocephalus. The ventricle size visualized on computed tomography scans was unremarkable, and shunt series were negative in both cases. Both patients began to present with brief periods of unresponsiveness, and video electroencephalography at that time showed periods of diffuse delta slowing. Lumbar punctures revealed increased opening pressures. Despite normal imaging and shunt series, both patients ultimately had increased intracranial pressure caused by shunt malfunction. This series demonstrates the difficulty of diagnosing potential transient increases in intracranial pressure based on standard-of-care diagnostics/examination and the potentially critical role for EEG in the identification of shunt malfunction.

Endoscopic Third Ventriculostomy versus Ventriculoperitoneal Shunt in Patients with Obstructive Hydrocephalus: An Updated Systematic Review and Meta-Analysis

Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) are surgical methods for treating obstructive hydrocephalus. However, there is still disagreement regarding the most effective technique, in terms of both operative success and postoperative complications. Therefore, we performed a systematic review and meta-analysis to compare the efficacy and safety of these two methods in patients with obstructive hydrocephalus. We performed a systematic search of the PubMed, Scopus, and Cochrane Library databases. Randomized clinical trials (RCTs) comparing ETV and VPS in pediatric or adult patients with obstructive hydrocephalus were included. The outcomes included were operative success, postoperative cerebrospinal fluid leak, postoperative infection, postoperative or intraoperative bleeding, blockage rate, and mortality. The risk ratio (RR) was calculated with a 95% confidence interval (CI). Heterogeneity was evaluated with I 2 statistics. We used a fixed-effects model for outcomes with I 2  < 25% and DerSimonian and Laird random-effects model for other conditions. The Cochrane collaboration tool for assessing the risk of bias in randomized trials was used for risk-of-bias assessment. R, version 4.2.1, was used for statistical analyses. Of the 2,353 identified studies, 5 RCTs were included, involving 310 patients with obstructive hydrocephalus, of which 163 underwent ETV. There was a significant difference in favor of ETV for postoperative infection (risk ratio [RR]: 0.11; 95% confidence interval [CI]: 0.04-0.33; p  < 0.0001; I 2  = 0%) and blockage rate (RR: 0.15; 95% CI: 0.03-0.75; p  = 0.02; I 2  = 53%). Meanwhile, there was no significant difference between groups for the postoperative or intraoperative bleeding (RR: 0.44; 95% CI: 0.17-1.15; p  = 0.09; I 2  = 0%), postoperative cerebrospinal fluid leak (RR: 0.65; 95% CI: 0.22-1.92; p  = 0.44; I 2  = 18%), operative success (RR: 1.18; 95% CI: 0.77-1.82; p  = 0.44; I 2  = 84%), and mortality (RR: 0.19; 95% CI: 0.03-1.09; p  = 0.06; I 2  = 0%). Three RCTs had some concerns about the risk of bias and one RCT had a high risk of bias due to the process of randomization and selection of reported results. Thus, this meta-analysis of RCTs evaluating ETV compared with VPS demonstrated that although there is no superiority of ETV in terms of operative success, the incidence of complications was significantly higher in patients who underwent VPS. Our results suggest that the use of ETV provides greater benefits for the treatment of obstructive hydrocephalus. However, more RCTs are needed to corroborate the superiority of ETV.

Intracranial thrombosis after ventriculoperitoneal shunting

We report a case of intracranial thrombosis (IT) after ventriculoperitoneal shunting (VPS). We reviewed the literature to highlight the importance of considering the possibility of cerebral venous thrombosis following VPS, even though it is a rarely reported complication. A 14-year-old boy underwent distal catheter replacement due to its short size that was detected during a routine consultation. Five days postoperatively, he experienced nausea, vomiting, seizures, and headache. Although a diagnosis of meningitis was considered, diagnosis of IT was eventually confirmed through computed tomography venography and gadolinium magnetic angioresonance. The patient subsequently underwent anticoagulant therapy, which led to complete resolution of symptoms. In this report, we suggest a possible association between VPS and IT, which is a complication that is not commonly reported. The literature suggests that decreased blood flow due to over-drainage of CSF after VPS causes decreased head pressure, culminating in venous stasis and consequent thrombosis. In addition, the literature describes associations between IT and lumbar puncture (LP); therefore, it is important to consider the possibility of IT following these procedures.

A Proposed Protective Protocol Predicting Reduction of Shunt Infection

OBJECTIVE

To identify the best protective interventions against shunt infection and, hence, to find an appropriate protocol assumed to be associated with reduction of infection rates.

METHODS

A combined prospective-retrospective cohort study was conducted over a period of 5 years in 3 referral hospitals. Twelve interventions against infection practiced by blinded surgeons during ventriculoperitoneal shunt operations were surveyed and their association with the outcome of interest (i.e., shunt infection) was tested. Interventions proved to be associated with the outcome entered a multivariate logistic regression to identify the protective interventions.

RESULTS

Among a total of 392 cases, shunt infection was diagnosed in 11.5% with a median onset of 55 days. Patients' demographics, etiology of hydrocephalus, shunt-related factors, and type of preoperative antibiotics were not associated with shunt infection. Two-thirds of infected shunts revealed Staphylococcus species. Among the tested interventions, double-gloving and device and wound irrigation using vancomycin solution and the use of incision adhesive drapes proved to exhibit a significant protective effect against shunt infection, whereas operative time <40 minutes revealed a marginal protective benefit.

CONCLUSIONS

Shunt infection is a significant complication that occurs early during the first 2 months after surgery. According to the study findings, an appropriate protocol against shunt infection is assumed to be composed of double-gloving, device and wound irrigation using vancomycin solution, and the use of incision adhesive drapes. Reduced operative time had a beneficial effect against shunt infection, although it was of marginal significance in the current study.

The Role of Antisiphon Devices in the Prevention of Central Ventricular Catheter Obliteration for Hydrocephalus: A 15-Years Institution's Experience Retrospective Analysis

Shunt over-drainage in patients harboring a ventriculoperitoneal shunt constitutes one of the most devastating, and difficult to manage, side effects associated with this operation. Siphoning is one of the most important contributing factors that predispose to this complication. Based on the fact that the predisposing pathophysiologic mechanism is considerably multiplicated, amelioration of that adverse condition is considerably difficult to achieve. A lot of evidence suggests that the widespread utilization of gravitational valves or antisiphon devices is of utmost importance, in order to minimize or even avoid the occurrence of such complications. The recent literature data highlight that gravity-related, long-lasting shunt over-drainage consists of a momentous factor that could be considered one of the main culprits of central shunt failure. A lot of efforts have been performed, in order to design effective means that are aimed at annihilating siphoning. Our tenet was the investigation of the usefulness of the incorporation of an extra apparatus in the shunt system, capable of eliminating the impact of the siphoning effect, based on the experience that was gained by their long-term use in our institution. A retrospective analysis was performed, based on the data that were derived from our institution’s database, centered on patients to which an ASD was incorporated into their initial shunt device between 2006 and 2021. A combination of clinical, surgical, radiological findings, along with the relevant demographic characteristics of the patients were collected and analyzed. We attempted to compare the rates of shunt dysfunction, attributed to occlusion of the ventricular catheter, in a group of patients, before and after the incorporation of an anti-siphon device to all of them. A total number of 120 patients who have already been shunted due to hydrocephalus of different etiologies, were managed with the insertion of an ASD. These devices were inserted at different anatomical locations, which were located peripherally to the initially inserted valvular mechanism. The data that were collected from a subpopulation of 17 of these patients were subjected to a separate statistical analysis because they underwent a disproportionately large number of operations (i.e., >10-lifetime shunt revisions). These patients were studied separately as their medical records were complicated. The analysis of our records revealed that the secondary implementation of an ASD resulted in a decrease of the 1-year and 5-year central catheter dysfunction rates in all of our patients when compared with the relevant obstruction rates at the same time points prior to ASD insertion. According to our data, and in concordance with a lot of current literature reports, an ASD may offer a significant reduction in the obstruction rates that is related to the ventricular catheter of the shunt. These data could only be considered preliminary and need to be confirmed with prospective studies. Nevertheless, this study could be considered capable of providing supportive evidence that chronic shunt over-drainage is a crucial factor in the pathophysiology of shunt malfunction. Apart from that, it could provide pilot data that could be reviewed in order to organize further clinical and laboratory studies, aiming toward the assessment of optimal shunt valve systems that, along with ASD, resist siphoning.

Escape from Prism

A 14-year-old boy with a history of shunted congenital hydrocephalus began having headaches with nausea and vomiting after transcontinental flights. He gradually developed horizontal diplopia indicative of mild bilateral sixth nerve palsy, without papilledema or ventriculomegaly. Intracranial pressure monitoring showed no signs of elevation. After he subsequently developed papilledema, surgical exploration showed shunt malfunction, and shunt replacement produced rapid resolution of symptoms. This case demonstrates the importance of relying on clinical history and neuro-ophthalmologic examination in patients with hydrocephalus and suspected shunt failure, even when objective confirmatory evidence of intracranial pressure elevation is lacking.

Refined Temporal-to-Frontal Horn Shunt for Treatment of Trapped Temporal Horn After Surgery of Peri- or Intraventricular Tumor: A Case Series Study

Background

Trapped temporal horn (TTH) is a localized hydrocephalus that can be treated with cerebrospinal fluid diversion. Refined temporal-to-frontal horn shunt (RTFHS) through the parieto-occipital approach is rarely reported in the literature and its effectiveness remains unclear. The aim of the present study is to investigate the efficacy and outcome of RTFHS for treatment of TTH.

Materials and Methods

We consecutively enrolled 10 patients who underwent RTFHS for TTH after surgical resection of peri- or intraventricular tumors from February 2018 to March 2021. Clinical, radiological, and follow-up data were collected and analyzed. The most common underlying pathology was meningioma (n=4), followed by central neurocytoma (n=3), thalamic glioblastoma (n=2), and anaplastic ependymoma (n=1).

Results

The mean Karnofsky performance scale (KPS) score and TTH volume at onset were 54.0 ± 15.1 (range 40-80) and 71.3 ± 33.2cm³ (range 31.7-118.6cm³), respectively. All patients (10/10, 100.0%) presented with periventricular brain edema (PVBE), while midline shift was observed in 9 patients (9/10, 90.0%). RTFHSs were implanted using valveless shunting catheters. No patients developed acute intracranial hemorrhage or new neurological deficit postoperatively. During the follow-up of 17.2 ± 13.7 months (range 3-39 months), all patients showed clinical and radiological improvement. The mean KPS score at the last follow-up was significantly increased to 88.0 ± 10.3 (range 70-100, p<0.0001). RTFHS resulted in significant complete remission in PVBE and midline shift in 8 (80.0%, p=0.0007) and 9 (100.0%, p=0.0001) patients, respectively. As the postoperative follow-up duration prolonged, the mean TTH volume decreased in a consistent, linear trend (p<0.0001). At last follow-up, the mean TTH volume was significantly reduced to 15.4 ± 11.5 cm³ (range 5.6-44.1 cm³, p=0.0003), resulting in a mean relative reduction of 77.2 ± 13.1% compared with the volume of TTH at onset. Over drainage was not observed during the follow-up. No patient suffered from proximal or distal shunt obstruction or shunt related infection, and the revision rate was 0%.

Conclusion

RTFHS seems to be safe and effective for the treatment of TTH with favorable outcomes. Advantages of this technique could be technically less complex and invasive, cost-effective, avoidance of various intraperitoneal complications, and maintaining a near-physiological CSF pathway.

Sheath formation around peritoneal tube: possible explanation for unknown cause of ventriculoperitoneal shunt failure

Ventriculoperitoneal (VP) shunt failures are common and are frequently associated with an obstruction of the peritoneal tube. This study aimed to explore the possible causes of peritoneal tube obstruction, which are largely unknown. From January 1981 to June 2018, we performed VP shunting in 646 patients with hydrocephalus. Among the procedures performed, 148 shunt revision procedures were performed in 98 patients with VP shunt failure. Of the study participants, 64 (43.2%) patients were diagnosed with peritoneal tube obstruction and five patients developed sheath formation that obstructed the end of the peritoneal tubes. Sheath formation around the peritoneal tube is a possible cause of VP shunt dysfunction.

Ventriculoperitoneal Shunt Drainage Increases With Gravity and Cerebrospinal Fluid Pressure Pulsations: Benchtop Model

BACKGROUND

There have been few improvements in cerebrospinal fluid (CSF) shunt technology since John Holter introduced the silicon valve, with overdrainage remaining a major source of complications.

OBJECTIVE

To better understand why valves are afflicted by supra-normal CSF flow rates. We present in Vitro benchtop analyses of flow through a differential pressure valve under simulated physiological conditions.

METHODS

The pseudo-ventricle benchtop valve testing platform that comprises a rigid pseudo-ventricle, compliance chamber, pulsation generator, and pressure sensors was used to measure flow rates through a differential pressure shunt valve under the following simulated physiological conditions: orientation (horizontal/vertical), compliance (low/medium/high), and pulsation generator force (low/medium/high).

RESULTS

Our data show that pulse pressures are faithfully transmitted from the ventricle to the valve, that lower compliance and higher pulse generator forces lead to higher pulse pressures in the pseudo-ventricle, and that both gravity and higher pulse pressure lead to higher flow rates. The presence of a valve mitigates but does not eliminate these higher flow rates.

CONCLUSION

Shunt valves are prone to gravity-dependent overdrainage, which has motivated the development of gravitational valves and antisiphon devices. This study shows that overdrainage is not limited to the vertical position but that pulse pressures that simulate rhythmic (eg, cardiac) and provoked (eg, Valsalva) physiological CSF pulsations increase outflow in both the horizontal and vertical positions and are dependent on compliance. A deeper understanding of the physiological parameters that affect intracranial pressure and flow through shunt systems is prerequisite to the development of novel valves.

Tetraventricular noncommunicating hydrocephalus: Case report and literature review

BACKGROUND

Tetraventricular hydrocephalus is a common presentation of communicating hydrocephalus. Conversely, cases with noncommunicating etiology impose a diagnostic challenge and are often neglected and underdiagnosed. Herein, we present a review of literature for clinical, diagnostic, and surgical aspects regarding noncommunicating tetrahydrocephalus caused by primary fourth ventricle outlet obstruction (FVOO), illustrating with a case from our service.

METHODS

We performed a research on PubMed database crossing the terms "FVOO," "tetraventriculomegaly," and "hydrocephalus" in English. Fifteen articles (a total of 34 cases of primary FVOO) matched our criteria and were, therefore, included in this study besides our own case.

RESULTS

Most cases presented in adulthood (47%), equally divided between male and female. Clinical presentation was unspecific, commonly including headache, nausea, and dizziness as symptoms (35.29%, 21.57%, and 9.80%, respectively), with ataxic gait (65%) and papilledema (40%) being the most frequent signs. MRI and CT were the imaging modalities of choice (11 patients each), often associated with CSF flow studies, such as cine MRI and CT ventriculogram. Endoscopic third ventriculostomy (ETV) was both the most popular and effective surgical approach (50.85% of cases, with 18.91% of recurrence) followed by ventricle-peritoneal shunt (16.95% of patients, 23.0% of recurrence).

CONCLUSION

FVOO stands for a poorly understood etiology of noncommunicating tetrahydrocephalus. With the use of ETV, these cases, once hopeless, had its morbimortality and recurrence reduced greatly. Therefore, its suspicion and differentiation from other forms of tetrahydrocephalus can improve its natural course, reinforcing the importance of its acknowledgment.

Ventriculoperitoneal shunt failure in pediatric patients: an analysis of a national hospitalization database in Thailand

OBJECTIVE

Shunt failure is common among patients undergoing ventriculoperitoneal shunting for treatment of hydrocephalus. The present study examined long-term shunt failure and associated risk factors in pediatric patients by using a national hospitalization database of Thailand.

METHODS

Patients 17 years or younger who had been admitted to 71 public hospitals in 2012-2017 for first-time ventriculoperitoneal shunting for diseases with known etiology and discharged alive were followed through 2019 to ascertain shunt failure. Shunt survivals were calculated using Kaplan-Meier estimates and time to failure was analyzed to identify risk factors for the first failure by using Cox proportional hazards regression. Differences in risks of subsequent failures with respect to place in the order of failures (i.e., first, second, third) were determined using a cumulative hazard function.

RESULTS

Over a median follow-up of 29.9 months, shunt failure occurred in 33.7% of 2072 patients (median age 8.8 months), with a higher proportion in patients < 1 year than in patients 1-17 years (37.8% vs 28.9%, p < 0.001), and ranged from 26.1% of those having posttraumatic hydrocephalus to 35.9% of those having infectious diseases. The shunt failure rates at 3, 6, and 12 months were 11.5%, 19.0%, and 25.2%, respectively. Patients < 1 year had a higher risk of the first failure than patients 1-17 years (hazard ratio 1.45, 95% CI 1.20-1.76). Among those with shunt failure, 35.8% had multiple failures and 52.9% failed within 180 days after the index shunting. The cumulative hazard of subsequent failure was consistently higher than that of an earlier failure regardless of age and etiology, and the cumulative hazard of the second failure in the patients with 180-day failure was higher than that in the patients in whom shunts failed beyond 180 days.

CONCLUSIONS

Shunt failure occurred more frequently in younger pediatric patients. Much attention should be placed on the initial shunt operation so as to mitigate the failure risk. Close follow-up was crucial once patients had developed the failure, because the risk of subsequent failure was more likely than an earlier one among those with multiple failures.

The survival of reimplanted shunts following externalization: a single-institution cohort study

OBJECTIVE

The failure-free survival of ventriculoperitoneal shunts (VPSs) following externalization for distal catheter infection or malfunction has not been adequately explored. Conversion to a ventriculoatrial shunt (VAS) may allow earlier reinternalization in lieu of waiting for the peritoneum to be suitable for reimplantation. This option is tempered by historical concerns regarding high rates of VAS failure, and the risks of rare complications are rampant.

METHODS

In this retrospective cohort study, all patients undergoing externalization of a VPS at a single institution between 2005 and 2020 were grouped according to the new distal catheter terminus location at the time of reinternalization (VPS vs VAS). The primary outcomes were failure-free shunt survival and duration of shunt externalization. Secondary outcomes included early (< 6 months) shunt failure.

RESULTS

Among 36 patients, 43 shunt externalization procedures were performed. Shunts were reinternalized as VPSs in 25 cases and VASs in 18 cases. The median failure-free survival was 1002 (interquartile range [IQR] 161-3449) days for VPSs and 1163 (IQR 360-2927) days for VASs. There was no significant difference in shunt survival according to the new distal catheter terminus (log-rank, p = 0.73). Conversion to a VAS was not associated with shorter duration of shunt externalization (Wilcoxon rank-sum, p = 0.64); the median duration was 7 (IQR 5-11) days for VPSs and 8 (IQR 6-15) days for VASs. No rare complications occurred in the VAS group.

CONCLUSIONS

Shunt failure-free survival rates following externalization are similar to published survival rates for nonexternalized shunts. There was no significant difference in survival between reinternalized VPSs and VASs. Although the VAS was not associated with a shortened duration of externalization, this finding is confounded by strong institutional preference for the VPS over the VAS. Early conversion to the VAS may be a viable treatment option in light of reassuring modern VAS survival data.

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.

Multimodal Sensing Capabilities for the Detection of Shunt Failure

Hydrocephalus is a medical condition characterized by the abnormal accumulation of cerebrospinal fluid (CSF) within the cavities of the brain called ventricles. It frequently follows pediatric and adult congenital malformations, stroke, meningitis, aneurysmal rupture, brain tumors, and traumatic brain injury. CSF diversion devices, or shunts, have become the primary therapy for hydrocephalus treatment for nearly 60 years. However, routine treatment complications associated with a shunt device are infection, obstruction, and over drainage. Although some (regrettably, the minority) patients with shunts can go for years without complications, even those lucky few may potentially experience one shunt malfunction; a shunt complication can require emergency intervention. Here, we present a soft, wireless device that monitors distal terminal fluid flow and transmits measurements to a smartphone via a low-power Bluetooth communication when requested. The proposed multimodal sensing device enabled by flow sensors, for measurements of flow rate and electrodes for measurements of resistance in a fluidic chamber, allows precision measurement of CSF flow rate over a long time and under any circumstances caused by unexpected or abnormal events. A universal design compatible with any modern commercial spinal fluid shunt system would enable the widespread use of this technology.

Evaluating the Effects of Cerebrospinal Fluid Protein Content on the Performance of Differential Pressure Valves and Antisiphon Devices Using a Novel Benchtop Shunting Model

BACKGROUND

Hydrocephalus is managed by surgically implanting flow-diversion technologies such as differential pressure valves and antisiphoning devices; however, such hardware is prone to failure. Extensive research has tested them in flow-controlled settings using saline or de-aerated water, yet little has been done to validate their performance in a setting recreating physiologically relevant parameters, including intracranial pressures, cerebrospinal fluid (CSF) protein content, and body position.

OBJECTIVE

To more accurately chart the episodic drainage characteristics of flow-diversion technology. A gravity-driven benchtop model of flow was designed and tested continuously during weeks-long trials.

METHODS

Using a hydrostatic pressure gradient as the sole driving force, interval flow rates of 6 valves were examined in parallel with various fluids. Daily trials in the upright and supine positions were run with fluid output collected from distal catheters placed at alternating heights for extended intervals.

RESULTS

Significant variability in flow rates was observed, both within specific individual valves across different trials and among multiple valves of the same type. These intervalve and intravalve variabilities were greatest during supine trials and with increased protein. None of the valves showed evidence of overt obstruction during 30 d of exposure to CSF containing 5 g/L protein.

CONCLUSION

Day-to-day variability of ball-in-cone differential pressure shunt valves may increase overdrainage risk. Narrow-lumen high-resistance flow control devices as tested here under similar conditions appear to achieve more consistent flow rates, suggesting their use may be advantageous, and did not demonstrate any blockage or trend of decreasing flow over the 3 wk of chronic use.

Malignant Peritoneal Mesothelioma Arising in Young Adults With Long-standing Indwelling Intra-abdominal Shunt Catheters

Only 50% to 70% of patients with mesothelioma report asbestos exposure. Other exposures (eg, radiation) play a role in some cases, but some patients have no obvious cause. We describe a series of patients with long-standing indwelling intra-abdominal shunt catheters who developed malignant peritoneal mesothelioma, suggesting a novel association. We identified 7 patients who had shunts and subsequently developed mesothelioma (5 women; median age: 31 y, range: 18 to 45 y). Clinical history and pathology materials were reviewed, and RNA sequencing was performed. Clinical presentations varied; 6 patients had hydrocephalus and a ventriculoperitoneal shunt, and 1 patient had portal hypertension and a portoatrial shunt. The median duration of shunt therapy in 5 cases was 29 years (range: 12 to 35 y); the remaining 2 patients also had shunts for many years, but specific details were unavailable. Two patients had radiotherapy for malignancies in childhood. One had an alleged exposure to asbestos and 1 had prior exposure to talc. The rest had no known risk factors. Histologically, all tumors were purely epithelioid. Treatments included surgical debulking, chemotherapy, and palliative care. All 7 died of disease (median survival: 7 mo, range: 1 to 18 mo). Molecular testing showed loss of NF2 and CDKN2A/B and a BAP1 mutation in 1 case, and no genomic alterations associated with mesothelioma in 2 cases. Peritoneal mesothelioma may represent a complication of long-standing indwelling shunt catheters. The mechanism is unknown, but chronic peritoneal irritation may play a role. Albeit rare, mesothelioma should be considered in patients with a shunt who present with new ascites.

Abdominal Complications Related to Ventriculoperitoneal Shunt Placement: A Comprehensive Review of Literature

Ever since the shunt device became the gold standard treatment for hydrocephalus, complications due to infections and mechanical problems have increased while lives have been saved. In addition, abdominal complications have become an important issue as the peritoneum is now the main place to insert the distal catheter. The most common complications were abdominal pseudocyst, distal catheter migration, inguinal hernia, catheter disconnection, and intestinal obstruction. The pediatric population is more prone to develop most of these complications due to their rapidly growing body, weaker abdominal musculature, and increased intraabdominal pressure. The goal of this review was to study the main aspects associated with abdominal complications after ventriculoperitoneal shunt (VPS) insertion, including the pathophysiology, epidemiological aspects, as well as the rationale for management and prevention according to the current “state-of-the-art.” It is paramount to recognize the risk factors associated with various types of complications to manage them properly.

An adjustable gravitational valve for initial VP-shunt treatment in hydrocephalic preterm neonates and infants below 1 year of age

OBJECTIVE

Shunt treatment for hydrocephalus in children should aim for sustainable flexibility in regard to optional, perspective pressure level adjustment during advancing physical and mental development. Gravitation-assisted shunt valves are designed to prevent hydrostatic over-drainage frequently observed in the long course of shunt-treated hydrocephalus. We prospectively studied and analyzed the implication, safety, and feasibility for an adjustable gravitational unit combined with a fixed differential-pressure (DP) valve for neonates and infants primary shunted within the first 12 months of life.

METHODS

Clinical course of hydrocephalic neonates and infants who received initial VP-shunt insertion in the early post-natal phase were monitored prospectively on the basis of our digital institutional Hydrocephalus & Shunt Registry. All patients were equipped with a fixed DP valve combined with a programmable gravitational unit activated in upright body position. Patients with a minimum shunt follow-up of 24 months were considered for further statistical analysis regarding hydrocephalus etiology, surgical setting, pre- and post-operative ventricular enlargement, head circumference, valve pressure setting, implication for the adjustment option of the gravitational unit, type and number of shunt complications, and revision-free shunt and valve survival.

RESULTS

Seventy-eight pediatric patients received primary VP-shunt insertion at a mean age of 10 weeks with age gestationally corrected for preterm neonates. Hydrocephalus was related to perinatal IVH (64%), CNS malformation (11%), spina bifida (9%), congenital aqueductal stenosis (9%), and idiopathic (4%) or post-infectious etiology (3%). Fifty-two patients (70%) presented with history of prematurity (gestational age 23-36 weeks). Regular follow-up carried out for a mean period of 63 months demonstrated that ventricular enlargement decreased significantly after applied treatment and excessive head growth could be counteracted effectively. At least one pressure level adjustment was performed in 31% of all patients after 12 months, in 42% after 24 months, and in 64% at the time of last clinical follow-up since initial shunt insertion. Pressure level adjustments were successful in cases of clinical or radiographic signs of under- or over-drainage for individual patients of various ages during entire clinical course. Mean pressure setting for upright position was 24.1 cm H₂O at the time of initial shunt insertion and increased to 26.4 cmH₂O at the time of last clinical follow-up. Revision-free shunt-survival rates after 12 and 24 months were 79% and 70% and valve-survival rates 91% and 90%, respectively.

CONCLUSION

The combination of a fixed DP valve with an adjustable gravitational unit utilized as first-line shunt regimen was feasible and safe in a highly vulnerable subgroup of hydrocephalic infants. The adjustment option for the gravitational unit showed frequent and increasing implication over time and was beneficial even during the very early developmental stage of limited autonomous mobility. To our knowledge this is the first ever reported long-term investigation of an age-consistent pediatric patient collective primary shunted with an adjustable gravitational valve system.

Gillespie C, Hennigan D, Bagga V, Mallucci C, Pettorini B. Efficacy and safety of the Miethke programmable differential pressure valve (proGAV®2.0): a single-centre retrospective analysis

PURPOSE

Achieving decompression without CSF over-drainage remains a challenge in hydrocephalus. Differential pressure valves are a popular treatment modality, with evidence suggesting that incorporation of gravitational units helps minimise over-drainage. This study seeks to describe the utility of the proGAV®2.0 programmable valve in a paediatric population.

METHODS

Clinical records and imaging of all patients fitted with proGAV®2.0 valves and Miethke fixed-pressure valves between 2014 and 2019 at our tertiary centre were analysed. Patient demographics, indication for shunt and valve insertion/revision and time to shunt/valve revision were collected. Ventricular linear metrics (fronto-occipital horn ratio (FOHR) and fronto-occipital horn width ratio (FOHWR)) were collected pre- and post-valve insertion. Microsoft Excel and SPSS v24 were used for data collection and statistical analysis.

RESULTS

Eighty-eight proGAV®2.0 valves were inserted in a population of 77 patients (n = 45 males (58%), mean age 5.1 years (IQR: 0.4-11.0 years)). A total of 102 Miethke fixed-pressure valves were inserted over the same time period. Median follow-up was 17.5 months (1.0-47.3). One (1.1%) proGAV®2.0 was revised due to over-drainage, compared to 2 (1.9%) fixed-pressure valves (p > 0.05). ProGAV®2.0 insertion resulted in a significant decrease in the mean number of revisions per patient per year (1.77 vs 0.25; p = 0.01). Overall shunt system survival with the proGAV®2.0 was 80.4% at 12 months, and mean time to revision was 37.1 months, compared to 31.0 months (95%CI: 25.7-36.3) and 58.3% in fixed-pressure valves (p < 0.01). Significant decreases were seen following proGAV®2.0 insertion in both FOHR and FOHWR, by 0.014 (95%CI: 0.006-0.023, p = 0.002) and 0.037 (95%CI: 0.005-0.069, p = 0.024) respectively.

CONCLUSION

The proGAV®2.0 provides effective decompression of hydrocephalic patients, significantly reduces the number of valve revisions per patient and had a significantly greater mean time to revision than fixed-pressure valves.

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.

Diagnostic modalities to determine ventriculoperitoneal shunt malfunction: A systematic review and meta-analysis

BACKGROUND

Ventriculoperitoneal (VP) shunt malfunction is an emergency. Timely diagnosis can be challenging because shunt malfunction often presents with symptoms mimicking other common pediatric conditions.

METHODS

We performed a systematic review and meta-analysis to determine which commonly used imaging modalities; Magnetic resonance imaging (MRI), Computed Tomography (CT), X-ray Shunt series or Optic Nerve Sheath Diameter (ONSD) ultrasound, are superior in evaluating shunt malfunction.

INCLUSION CRITERIA

patients less than 21 years old with symptoms of shunt malfunction. We calculated the pooled sensitivity, specificity, Likelihood Ratios (LR+, LR-) using a random-effects model.

RESULTS

Eight studies were included encompassing 1906 patients with a prevalence of VP shunt malfunction of (29.3%). Shunt series: sensitivity (14%-53%), specificity (99%), LR+ (23.2), and LR- (0.47-0.87). CT scan: sensitivity (53%-100%), specificity (27%-98%), LR+ (1.34-22.87), LR- (0.37). MRI: sensitivity (57%), specificity (93%), LR+ (7.66), and LR- (0.49). ONSD: sensitivity (64%), specificity (22%-68%), LR+ (4.4-8.7), LR- (0.93). A positive shunt series, CT scan, MRI, or ONSD has a post-test probability of (23%-84%). A normal shunt series, CT scan, MRI, or ONSD results in a post-test probability of (7%-31%). A positive shunt series results in a post-test probability of 80%, which is equivalent to the post-test probability of CT scan (23-84%) and MRI (83%).

CONCLUSION

Despite the low sensitivity, a positive shunt series obviates the need for further imaging studies. Prompt referral for neurosurgical intervention is recommended. A negative shunt series or any result (positive or negative) from CT, MRI, or ONSD will still require an emergent neurosurgical referral.

General surgery involvement with ventriculoperitoneal shunt insertions reduces revision rates

BACKGROUND

Ventriculoperitoneal shunts (VPS) are placed for a variety of etiologies. It is common for general surgery to assist with insertion of the distal portion in the peritoneum.

OBJECTIVE

To determine if there is a difference in revision rates in patients undergoing VPS placement with general surgery as well as those undergoing laparoscopic insertion.

METHODS

A retrospective review of all consecutive patients undergoing VPS placements was performed in a three-year period (2017-2019). Those that underwent placement with general surgery were compared to those without general surgery. Additionally, patients undergoing distal placement via mini-laparotomy versus laparoscopy were compared. Multivariable logistic regression was used to examine risk factors for distal VPS failure.

RESULTS

331 patients were included. 202 (61.0 %) underwent VPS placement with general surgery. 121 (36.6 %) patients underwent insertion via laparoscopic technique. General surgery involvement reduced operative times, decreased length of stay, and lowered overall revision rates with distal revision rates being most significant (1.5 % vs 8.5 %; p = 0.0034). Patients undergoing VPS placement via laparoscopic technique had decreased operative time, length of stay, in-hospital complications and revision rates, with significant decrease in shunt infection (1.7 % vs 7.1 %; p = 0.0366). A history of prior shunt or abdominal surgery (OR 3.826; p = 0.0282) and lack of general surgery involvement (OR 20.98; p = 0.0314) are independent risk factors for distal shunt revision in our cohort.

CONCLUSION

The use of general surgeons in VPS insertion can be of benefit by decreasing operative time, length of stay, total revisions, and distal revision rates. Further prospective studies are warranted to determine true benefit.

Pseudofailure of Ventriculoperitoneal Shunt due to Drug-Resistant Constipation, Dramatically Responsive to Rectal Tube Placement: Pitfall Case Series of Avoidable Shunt Revision

BACKGROUND

Ventriculoperitoneal shunt placement is a common standard treatment for hydrocephalus, and these shunts function appropriately in the presence of a pressure gradient between the ventricular and abdominal cavities.

CASE DESCRIPTION

We encountered 2 cases of shunt malfunction that was due to an increase in intra-abdominal pressure, mainly caused by constipation and excessive accumulation of enteric gas. Although aggressive bowel regimens were implemented, this management failed in both patients. Careful physical examination revealed unusually elevated tonus of the anus sphincter muscle, and a fecal incontinence catheter was inserted into the rectum. Following this procedure, constipation rapidly improved together with a marked reduction in enteric gas, leading to a normalization of ventricular size on imaging and neurologic improvements. Both patients were able to avoid unnecessary surgical exploration or shunt revision.

CONCLUSIONS

Constipation is one of the differential diagnoses of ventriculoperitoneal shunt malfunction, and bowel regimens are the first-line treatment. However, some cases can prove resistant to medical therapy, and mechanical tube placement can provide an alternative or additional solution. Before proceeding to surgical exploration, the intra-abdominal environment should be properly assessed and every option should be explored to address underlying causes of shunt failure to avoid unnecessary intervention.

In vitro performance of combinations of anti-siphon devices with differential pressure valves in relation to the spatial position

BACKGROUND

Programmable differential pressure (DP) valves combined with an anti-siphon device (ASD) represent the current standard of care in preemtping overdrainage associated with ventriculoperitoneal shunting for hydrocephalus.

OBJECTIVE

We aimed to provide comparative data of four combinations of two ASDs of different working principles in combination with two DP valves in an in vitro model in order to achieve a better understanding of the flow characteristics and potential clinical application.

METHODS

We analyzed the flow performance of four possible combinations of two DP valves (CHPV [HM]; proGAV 2.0[PG]) in combination with either a gravity-regulated (Shuntassistant [SA]) or a flow-regulated (SiphonGuard [SG]) ASD in an in vitro setup. A DP between 4 and 60 cmH₂O was generated, and the specific flow characteristics were measured. In addition, the two combinations with gravity-regulated ASDs were measured in defined spatial positions.

RESULTS

Flow characteristics of the SA combinations corresponded to the DP in linear fashion and to the spatial position. Flow characteristics of the SG combinations were dependent upon the DP in a non-linear fashion and independent of the spatial position. Highest mean flow rate of the PG-SG- (HM-SG-) combination was 1.41 ± 0.24 ml/min (1.16 ± 0.06 ml/min). The mean flow rates sharply decreased with increasing inflow pressure and subsequently increased slowly up to 0.82 ± 0.26 ml/min (0.77 ± 0.08 ml/min).

CONCLUSION

All tested device combinations were able to control hydrostatic effect and prevent consecutive excessive flow, to varying degrees. However, significant differences in flow characteristics can be seen, which might be relevant for their clinical application.

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.

Ventriculoperitoneal Shunts in the Emergency Department: A Review

In this paper, we review the indications, complications, and pitfalls associated with ventriculoperitoneal (VP) shunts. As most VP shunt problems initially present to the emergency department, it is important for emergency physicians to be well-versed in managing them. In the article, the possible reasons for shunt failure are explored and summarized using an infographic. We also examine potential clinical presentations of VP shunt failure.

A 12-year single-center retrospective analysis of antisiphon devices to prevent proximal ventricular shunt obstruction for hydrocephalus

OBJECTIVE

Recent evidence points to gravity-dependent chronic shunt overdrainage as a significant, if not leading, cause of proximal shunt failure. Yet, shunt overdrainage or siphoning persists despite innovations in valve technology. The authors examined the effectiveness of adding resistance to flow in shunt systems via antisiphon devices (ASDs) in preventing proximal shunt obstruction.

METHODS

A retrospective observational cohort study was completed on patients who had an ASD (or additional valve) added to their shunt system between 2004 and 2016. Detailed clinical, radiographic, and surgical findings were examined. Shunt failure rates were compared before and after ASD addition.

RESULTS

Seventy-eight patients with shunted hydrocephalus were treated with placement of an ASD several centimeters distal to the primary valve. The records of 12 of these patients were analyzed separately due to a complex shunt revision history (i.e., > 10 lifetime shunt revisions). The authors found that adding an ASD decreased the 1-year ventricular catheter obstruction rates in the "simple" and "complex" groups by 67.3% and 75.8%, respectively, and the 5-year rates by 43.3% and 65.6%, respectively. The main long-term ASD complication was ASD removal for presumed valve pressure intolerance in 5 patients.

CONCLUSIONS

Using an ASD may result in significant reductions in ventricular catheter shunt obstruction rates. If confirmed with prospective studies, this observation would lend further evidence that chronic shunt overdrainage is a central cause of shunt malfunction, and provide pilot data to establish clinical and laboratory studies that assess optimal ASD type, number, and position, and eventually develop shunt valve systems that are altogether resistant to siphoning.

Intraoperative measurement of intraventricular pressure in dogs with communicating internal hydrocephalus

Collapse of the lateral cerebral ventricles after ventriculo-peritoneal drainage is a fatal complication in dogs with internal hydrocephalus. It occurs due to excessive outflow of cerebrospinal fluid into the peritoneal cavity (overshunting). In most shunt systems, one-way valves with different pressure settings regulate flow into the distal catheter to avoid overshunting. The rationale for the choice of an appropriate opening pressure is a setting at the upper limit of normal intracranial pressure in dogs. However, physiological intraventricular pressure in normal dogs vary between 5 and 12 mm Hg. Furthermore, we hypothesise that intraventricular pressure in hydrocephalic dogs might differ from pressure in normal dogs and we also consider that normotensive hydrocephalus exists in dogs, as in humans. In order to evaluate intraventricular pressure in hydrocephalic dogs, twenty-three client owned dogs with newly diagnosed communicating internal hydrocephalus were examined before implantation of a ventriculo-peritoneal shunt using a single use piezo-resistive strain-gauge sensor (MicroSensor ICP probe). Ventricular volume and brain volume were measured before surgery, based on magnetic resonance images. Total ventricular volume was calculated and expressed in relation to the total volume of the brain, including the cerebrum, cerebellum, and brainstem (ventricle-brain index). Multiple logistic regression analysis was performed to assess the influence of the covariates "age", "gender", "duration of clinical signs", "body weight", and "ventricle-brain index" on intraventricular pressure. The mean cerebrospinal fluid pressure in the hydrocephalic dogs was 8.8 mm Hg (standard deviation 4.22), ranging from 3-18 mm Hg. The covariates "age", (P = 0.782), "gender" (P = 0.162), "body weight", (P = 0.065), or ventricle-brain index (P = 0.27)" were not correlated with intraventricular pressure. The duration of clinical signs before surgery, however, was correlated with intraventricular pressure (P< 0.0001). Dogs with internal hydrocephalus do not necessarily have increased intraventricular pressure. Normotensive communicating hydrocephalus exists in dogs.

Collection and Analyses of Cerebrospinal Fluid for Pediatric Translational Research

Cerebrospinal fluid sample collection and analysis is imperative to better elucidate central nervous system injury and disease in children. Sample collection methods are varied and carry with them certain ethical and biologic considerations, complications, and contraindications. Establishing best practices for sample collection, processing, storage, and transport will ensure optimal sample quality. Cerebrospinal fluid samples can be affected by a number of factors including subject age, sampling method, sampling location, volume extracted, fraction, blood contamination, storage methods, and freeze-thaw cycles. Indicators of sample quality can be assessed by matrix-associated laser desorption/ionization time-of-flight mass spectrometry and include cystatin C fragments, oxidized proteins, prostaglandin D synthase, and evidence of blood contamination. Precise documentation of sample collection processes and the establishment of meticulous handling procedures are essential for the creation of clinically relevant biospecimen repositories. In this review we discuss the ethical considerations and best practices for cerebrospinal fluid collection, as well as the influence of preanalytical factors on cerebrospinal fluid analyses. Cerebrospinal fluid biomarkers in highly researched pediatric diseases or disorders are discussed.

Using a burr hole valve prevents proximal shunt failure in infants and toddlers

OBJECTIVE

Proximal malfunction is the most common cause of ventriculoperitoneal (VP) shunt failure in young children. In this study, the authors sought to determine factors that affect the migration rate of ventricular catheters in hydrocephalic children who undergo shunt implantation in the first 3 years of life.

METHODS

The authors reviewed the medical records and imaging studies of newly diagnosed and treated hydrocephalic children who were younger than 3 years. Patients who received VP shunt insertion through the parieto-occipital route were not included. In total, 78 patients were found who underwent VP shunt insertion between December 2006 and April 2017. Eighteen patients were excluded due to mortality, short follow-up period (< 1 year), and lack of imaging follow-up. The age, sex, etiology of hydrocephalus, initial length of ventricular catheter, valve type (burr hole vs non-burr hole), time to ventricular catheter migration, subsequent revision surgery, and follow-up period were analyzed. The diagnosis of a migrated ventricular catheter was made when serial imaging follow-up showed progressive withdrawal of the catheter tip from the ventricle, with the catheter shorter than 4 mm inside the ventricle, or progressive deviation of the ventricular catheter toward the midline or anterior ventricular wall.

RESULTS

Sixty patients were enrolled. The mean age was 5.1 months (range 1-30 months). The mean follow-up period was 50.9 months (range 13-91 months). Eight patients had ventricular catheter migration, and in 7 of these 8 patients a non-burr hole valve was used. In the nonmigration group, a non-burr hole valve was used in only 6 of the 52 patients. Six of the 8 patients with catheter migration needed second surgeries, which included removal of the shunt due to disconnection in 1 patient. The remaining 2 patients with shunt migration were followed for 91 and 46 months, respectively, without clinical and imaging changes. The authors found that patient age at catheter insertion, ventricular catheter length, and the use of a burr hole valve were protective factors against migration. After ventricular catheter length and patient age at catheter insertion were treated as confounding variables and adjusted with multivariable Weibull proportional hazards regression, the use of a burr hole valve shunt remained a protective factor.

CONCLUSIONS

The use of burr hole valves is a protective factor against ventricular catheter migration when the shunt is inserted via a frontal route. The authors suggest the use of a burr hole valve along with a frontal entry point in hydrocephalic children younger than 3 years to maintain long-term shunt function.

Laparoscopic insertion of ventriculoperitoneal shunts in pediatric patients - A retrospective cohort study

INTRODUCTION

Ventriculoperitoneal shunts (VPSs) are the mainstay of treatment of hydrocephalus but have frequent complications including shunt failure and infection. There has been no comparison of laparoscopic versus open primary VPS insertion in children. We hypothesized that laparoscopic VP shunt insertion may improve patient outcomes.

METHODS

A prospectively-maintained, externally-validated database of pediatric patients who underwent VPS insertion at a single center between 2012 and 2016 was reviewed. Outcomes including subsequent revisions, shunt infections, operative time, and hospital stay between open and laparoscopic groups were compared.

RESULTS

210 patients underwent VPS insertion - 41 laparoscopically and 169 open. Operative time was longer for laparoscopic insertions. There was no difference in shunt infections, complications or length of stay. There was no difference between overall revisions or in confirmed peritoneal obstructions in the laparoscopic (12%) versus open VPS insertions (5%), p = 0.13.

CONCLUSIONS

This first cohort analysis of laparoscopic versus open VPS insertion in pediatric patients indicates no difference in confirmed peritoneal obstructions. With increasing use of laparoscopic placement in some centers, it remains important to elucidate if there is a subset of pediatric patients who might benefit from this technique; possible candidates may be those who are overweight/obese or have had previous intra-abdominal surgery.

LEVEL OF EVIDENCE

III - Retrospective cohort study.

Mechanisms and Major Sites of Distal Catheter Migration in Ventriculoperitoneal Shunting Maneuvers: A Review Article

A ventriculoperitoneal shunt (VPS) is a medical device used to deflect cerebrospinal fluid from cerebral ventricles to the peritoneal cavity. Since 1908, ventriculoperitoneal shunts have been considered the best option in hydrocephalus management. Manifestation related to VPS may arise anywhere whilst tunneling the VPS from the ventricle to the peritoneal cavity, but complications associated with the distal catheter are especially common and a leading cause of revision surgeries. Among the many complications associated with peritoneal shunts, migration of the catheter into other parts of the body is still common. Scrotal migration mainly takes place in children aged 4 days to 5 years. Patent processus vaginalis, formation of an inguinal hernia, and increased intraabdominal pressure are leading risk factors associated with migration of the peritoneal catheter into the scrotum. Thoracic migration of peritoneal catheters predominantly occurs in adult patients. Important mechanisms in thoracic migration include (1) iatrogenic perforation of the external or internal jugular veins by the surgeon during tunneling and (2) gradual destruction of the venous structures by the catheter due to routine extension and flexion of the neck. After entering the vessel, negative intrathoracic pressure combined with positive intraabdominal pressure aids migration into the thoracic cavity. Sharp tips or shunt types contribute to intraabdominal migration and perforation.

Acute subdural hematomas in shunted normal-pressure hydrocephalus patients - Management options and literature review: A case-based series

Background:

Ventriculoperitoneal shunting (VPS) is considered a risk factor for developing subdural hematomas (SDH). Treating cases of acute SDH (aSDH) in shunted normal-pressure hydrocephalus (NPH) patients can be challenging, and data in this field are scarce. We report our experience treating shunted NPH patients presenting with aSDH.

Methods:

Eight patients, aged 73 ± 6 years, with a history of VPS for NPH, hospitalized because of aSDH were included in this study. We retrospectively analyzed data regarding patients’ clinical and radiological presentation, hospitalization course, the use of antithrombotics, and response to different treatment regimens.

Results:

Four patients had pure aSDH, three had acute on chronic SDH, and one had subacute SDH. Patients presented with GCS 13–15 and various neurological signs, mainly confusion and unsteady gate. Two cases improved following resetting of their programmable shunt valve to its maximal pressure setting. Six cases improved after evacuation of the hematomas, five of them were operated a few days after initially resetting of the valve pressure. Three patients were discharged home, whereas five were referred to rehabilitation. Extended Glasgow Outcome Scale scores at discharge and during long-term follow-up were 5 and 7, respectively.

Conclusions:

Treatment of patients with VPS for NPH, presenting with aSDH, may differ according to the neurological status, imaging, and clinical course. Treatment options include restricting shunt function, hematoma evacuation, or both.

Overdrainage-related ependymal bands: a postulated cause of proximal shunt obstruction

OBJECTIVEVentricular shunts have an unacceptably high failure rate, which approaches 50% of patients at 2 years. Most shunt failures are related to ventricular catheter obstruction. The literature suggests that obstructions are caused by in-growth of choroid plexus and/or reactive cellular aggregation. The authors report endoscopic evidence of overdrainage-related ventricular tissue protrusions ("ependymal bands") that cause partial or complete obstruction of the ventricular catheter.METHODSA retrospective review was completed on patients undergoing shunt revision surgery between 2008 and 2015, identifying all cases in which the senior author reported endoscopic evidence of ependymal tissue in-growth into ventricular catheters. Detailed clinical, radiological, and surgical findings are described.RESULTSFifty patients underwent 83 endoscopic shunt revision procedures that revealed in-growth of ventricular wall tissue into the catheter tip orifices (ependymal bands), producing partial, complete, or intermittent shunt obstructions. Endoscopic ventricular explorations revealed ependymal bands at various stages of development, which appear to form secondarily to siphoning. Ependymal bands are associated with small ventricles when the shunt is functional, but may dilate at the time of obstruction.CONCLUSIONSVentricular wall protrusions are a significant cause of proximal shunt obstruction, and they appear to be caused by siphoning of surrounding tissue into the ventricular catheter orifices.

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.

Parent/guardian knowledge regarding implanted shunt type, setting, and symptoms of malfunction/infection

OBJECTIVE Patients with shunts often interact with providers distant from their primary hospital, making it important that the parent(s)/guardian(s) is well versed in the type of shunt implanted and symptoms of malfunction/infection. This is particularly important with magnetic-sensitive programmable valves, as the use of MRI becomes more prevalent. METHODS Over a 6-month period, primary caregivers of 148 consecutive patients who received shunts were prospectively administered questionnaires at clinic visits. Caregivers were asked to do the following: 1) identify shunt valve name, type, and setting if applicable; 2) list symptoms of shunt malfunction/infection; and 3) indicate whether they had access to references regarding shunt type/setting, booklets from the Hydrocephalus Association, and quick reference cards with symptoms of shunt malfunction/infection. One cohort of caregivers (n = 75) was asked to carry informational cards with shunt valve/setting information (group I); this cohort was compared with another subgroup of caregivers (n = 73) not carrying cards (group II). RESULTS The mean (± SD) age of patients at implantation/revision was 3.71 ± 4.91 years, and the age at follow-up was 6.12 ± 5.4 years. The average time from surgery to administration of the questionnaire was 2.38 ± 3.22 years. There were 86 new shunt insertions and 62 revisions. One hundred twenty-eight caregivers (87%) could identify the type of valve (programmable vs nonprogrammable). On the other hand, only 72 caregivers (49%) could identify the valve name. Fifty-four of 73 (74%) caregivers of patients who had shunts with programmable valves could correctly identify the valve setting. One hundred caregivers (68%) had a copy of the Hydrocephalus Association booklet, and 103 (70%) had quick reference cards. Eighty caregivers (54%) had references on shunt type/setting. Most caregivers (127 [86%]) could name ≥ 3 signs/symptoms of shunt malfunction, with vomiting (61%), headache (49%), and sleeps more/lethargic (35%) most frequently reported. Caregivers of patients in group I were more likely to have cards with symptoms of shunt infection or malfunction (p = 0.015); have information cards regarding shunt type/setting (p < 0.001); and correctly identify valve type (p = 0.001), name (p < 0.001), and setting if programmable (p = 0.0016). There were no differences in ability to list symptoms of shunt malfunction or infection (p = 0.8812) or in access to Hydrocephalus Association booklets (p = 0.1288). There were no significant demographic differences between the groups, except that group I patients had a shorter time from surgery to last follow-up (1.66 vs 3.17 years; p = 0.0001). CONCLUSIONS Education regarding the care of patients with shunts by providing written cards with shunt type/setting and access to reference materials seems to be effective. Developing plans for guided instruction with assessment in the clinic setting of a caregiver's knowledge is important for patient safety.

A counterforce to diversion of cerebrospinal fluid during ventriculoperitoneal shunting: the intraperitoneal pressure. An observational study

BACKGROUND

Intraperitoneal pressure (IPP) counteracts the diversion of cerebrospinal fluid (CSF) from the cranial to the peritoneal compartment during ventriculoperitoneal shunting. Animal studies suggest that the intrinsic IPP exceeds the intraperitoneal hydrostatic pressure. The intrinsic IPP in mobile patients is relevant for shunt therapy, but data about it is not available.

METHODS

The IPP was measured indirectly in 25 mobile subjects (13 female) by applying a standard intravesical pressure measurement technique. Measurements were carried out in reference to the navel (supine position) and the xiphoid (upright position). Results were adjusted for the intraperitoneal hydrostatic pressure and correlated afterward with general body measures.

RESULTS

The corrected mean (SD) IPP measured in the supine position was 4.4 (4.5) cm H₂O, and the mean (SD) upright IPP was 1.6 (7.8) cm H₂O (p = 0.02). A positive correlation was found between the body mass index (BMI) and the IPP in the upright (r = 0.51) and supine (r = 0.65) body positions, and between the abdominal circumference and the IPP in the supine position (r = 0.63).

CONCLUSIONS

The intrinsic IPP in mobile subjects exceeds the intraperitoneal hydrostatic pressure. Thus, the intrinsic IPP counteracts the diversion of CSF into the peritoneal compartment. The intrinsic IPP is correlated with mobile patients' general body measures.

Laparoscopic management of abdominal pseudocyst following ventriculoperitoneal shunt implantation in hydrocephalus

Abdominal pseudocyst (AP) is quite a rare complication after ventriculoperitoneal shunting (VPS) for the treatment of hydrocephalus. Laparoscopy is an alternative method to open surgery with well-known advantages. There are not many reports of using laparoscopy to treat this condition and existing algorithms are based on small groups of patients; thus every case would give an additional insight into the treatment of this complication. A 37-year-old male patient with a history of VPS presented with headache, nausea and upper abdominal pain. Computed tomography of the abdominal cavity revealed a cyst in the left upper quadrant. After the ultrasound-guided percutaneous drainage the patient was qualified for laparoscopy. The cyst was removed laparoscopically under guidance of laparoscopic ultrasound. The patient recovered uneventfully with very good general and cosmetic results. In the follow-up period of 3 months we have not observed any abdominal or general health problems.