Cerebrospinal fluid diversion devices and infection. A comprehensive review

Effective Treatment of Acinetobacter baumannii Ventriculitis With Interventricular Colistin: A Case Report

Cerebrospinal fluid shunts are the primary treatment for hydrocephalus. However, prolonged external ventricular drain (EVD) use can lead to central nervous system (CNS) infections such as ventriculitis. In the ICU setting, nosocomial infections with gram-negative, multi-drug resistant (MDR) organisms such as Acinetobacter baumannii (AB) prevail, leading to poor outcomes. AB infections are notably challenging due to their genetic drug resistance. Colistin has been reintroduced for use against gram-negative MDR pathogens but has limitations in CNS penetration when administered intravenously. Therefore, intraventricular (IVT) or intrathecal administration of colistin is recommended to enhance its therapeutic reach within the CNS. We present a case of a 22-year-old male admitted after an electric scooter accident with head trauma and hydrocephalus. A ventriculoperitoneal (VP) shunt was inserted, complicated by a nosocomial neuroinfection. Empiric IV therapy with meropenem and vancomycin was initiated. The VP shunt culture identified AB susceptible only to colistin. Intravenous (IV) colistin was added to meropenem with no significant improvement. The addition of IVT colistin significantly improved the patient's neurological condition and reduced inflammatory markers. The patient experienced one myoclonic seizure during IVT colistin treatment, managed with antiepileptics. After multiple unrelated nosocomial complications, the patient was discharged in good condition to rehabilitation. This case suggests that IVT colistin, combined with IV administration, may be preferable over IV colistin alone. Medical staff should be informed about the correct prevention and care of EVD-associated infections.

Is It Possible to Eliminate Postoperative Shunt Infections?: Results of a Modified Hydrocephalus Clinical Research Network Protocol

BACKGROUND

 Postoperative shunt infection is a nightmare in neurosurgical practice with additional morbidity and mortality. A lot of protocols have contributed to the reduction of ventriculoperitoneal shunt (VPS) infections but not eradication. The aim of the study was to evaluate the rigid application of a modified Hydrocephalus Clinical Research Network (HCRN) protocol in the prevention of postoperative shunt infection.

METHODS

 We retrospectively evaluated children with congenital hydrocephalus who underwent VPS insertion, and in whom the protocol was applied from June 2019 to January 2020. Follow-up ranged from 11 to 24 months.

RESULTS

 Thirty-seven procedures were performed including 35 primary shunt insertions and two revision surgeries. The median age was 5 months (range, 1-30 months), and 25 patients were males. The most common cause for VPS placement was congenital hydrocephalus without identifiable cause in 28 cases (80%). The endoscope-assisted technique was used in the insertion of the proximal end in six cases (17%). The mean follow-up was 19.4 months (11-24 months). The rate of shunt infection was 0% till the last follow-up.

CONCLUSION

 The preliminary results showed an effective method for the prevention of postoperative shunt infections using the modified protocol. These initial findings need to be validated in a large prospective study before widespread application can be recommended.

Tunneled antibiotic-impregnated vs. bolt-connected, non-coated external ventricular drainage: a comparison of complications

Background

External ventricular drainage (EVD) is a common emergency neurosurgical procedure, but it is not free of adverse events. The aim of this study is to compare the complication rate of two frequently used EVD types, namely, tunneled antibiotic-impregnated catheters (Bactiseal©) and bolt-connected non-coated devices (Camino©).

Methods

All EVDs placed between 1 March 2015 and 31 December 2017 were registered. Procedures performed with any catheter different from Bactiseal© or Camino© EVD with incomplete follow-up and those EVDs placed due to infectious disease were excluded. Demographic and clinical variables, as well as the overall complication rate (infection, hemorrhage, obstruction, malposition of the catheter, and involuntary pull-out of the device) and the need for replacement of the EVD, were collected.

Results

A total of 77 EVDs were finally considered for analysis (40 Bactiseal® and 37 Camino®). There was a statistically significant difference in diagnosis and also in the location of the procedure, as more bolt-connected EVD was placed outside the operating room (97.3 vs. 23.5%, p < 0.001) due to emergent pathologies such as vascular diseases and spontaneous hemorrhages. In the univariate analysis, a statistically significantly higher rate of catheter involuntary pull-out (29.7 vs. 7.5%, p = 0.012) and the need for EVD replacement (32.4 vs. 12.5%, p = 0.035) was found in the Camino cohort. However, those differences could not be confirmed with multivariable analysis, which showed no association between the type of catheter and any of the studied complications. Ventriculostomy duration was identified as a risk factor for infection (OR 1.09, 95% CI 1.02-1.18).

Conclusion

No significant differences were observed regarding infection, hemorrhage, obstruction, malposition, involuntary catheter pull-out, and the need for EVD replacement when comparing non-impregnated bolt-connected EVDs (Camino®) with tunneled antibiotic-impregnated catheters (Bactiseal®). The duration of EVD was associated with an increased risk of infection.

Rapid Versus Gradual Weaning of External Ventricular Drain: A Systematic Literature Review and Meta-analysis

The insertion of an external ventricular drain (EVD) is one of the most common neurosurgical procedures. Whether the weaning method (gradual or rapid) influences the ventriculoperitoneal shunt (VPS) insertion rate has not been conclusively established. The aim of this study is to provide a systematic literature review and conduct a meta-analysis of studies comparing gradual with rapid EVD weaning regarding VPS insertion rate. Articles were identified by searching the Pubmed/Medline, Embase, and Web of Science databases throughout October 2022. Two independent researchers assessed the studies for inclusion and quality. We included randomized trials, prospective cohort studies, and retrospective cohort studies, which compared gradual and rapid EVD weaning. The primary outcome was VPS insertion rate, whereas secondary outcomes were EVD-associated infection (EVDAI) rate and length of stay in the hospital and intensive care unit (ICU). Four studies directly comparing rapid versus gradual EVD weaning, with 1337 patients suffering from subarachnoid hemorrhage, were identified and included in the meta-analysis. VPS insertion rate was 28.1% and 32.1% in patients with gradual and rapid EVD weaning, respectively (relative risk 0.85, 95% confidence interval 0.49-1.46, p = 0.56). Further, the EVDAI rate was comparable between the groups (gradual group 11.2%, rapid group 11.5%, relative risk 0.67, 95% confidence interval 0.24-1.89, p = 0.45), whereas length of stay in the ICU and hospital were significantly shorter in the rapid weaning group (2.7 and 3.6 days, respectively; p < 0.01). Rapid EVD weaning seems comparable to gradual EVD weaning concerning VPS insertion rates and EVDAI, whereas hospital and ICU length of stay is significantly reduced.

Characteristics and outcomes of cerebrospinal fluid shunt and drain-associated infections

INTRODUCTION

Data on infections associated with cerebrospinal fluid shunt (CSF-S) or device-associated infection (CSF-SDI) are limited in adults. We performed a retrospective study to describe characteristics, management, and outcome of CSF-SDI.

METHODS

All patients with CSF-SDI and admitted to our institution from January 2013 to December 2019 were included.

RESULTS

Among 50 patients, fifty-six episodes of CSF-SDI (41 external ventricular device-associated infections (CSF-D) and 15 other shunt infections (CSF-S) were included. The incidence of CSF-SDI was 11.9 %. Fever was the most common symptom (81 %). Enterobacterales were more prevalent in CSF-S than in CSF-D (20 % vs 53 %, p = 0.02). As regards CSF-D, deceased patients (11/41, 27 %) more frequently had a Glasgow coma scale score decreasing from baseline (p < 0.01), lower glycorrhachia (p < 0.01), a higher protein level in CSF (p = 0.001) and a positive control CSF culture (p = 0.031).

CONCLUSIONS

CSF-SDIs are rare but with a high mortality rate. Mortality was more closely related to the infection than to comorbidities or underlying neurosurgical disease. A second CSF analysis significantly helped to detect patients with CSF-D with a poor prognosis.

Cerebrospinal Fluid System Infection in Children with Cancer: A Retrospective Analysis over 14 Years in a Major European Pediatric Cancer Center

Infection of a cerebrospinal fluid system is a serious medical complication. We performed a retrospective monocentric analysis on temporary and permanent cerebrospinal fluid devices in children with and without cancer, covering a period of over 14 years. Between 2004 and 2017, 275 children with a cerebrospinal fluid system were seen at our institution. Thirty-eight children suffered from 51 microbiologically proven infectious episodes of the cerebrospinal fluid system (12 children with cancer and 26 children without cancer). Independently of the cerebrospinal fluid system used, the incidence of infection did not significantly differ between children with and without cancer and was the highest in children younger than one year. Infection occurred earlier in external ventricular drain (EVD) than ventriculoperitoneal (VP) shunt, and in EVD significantly earlier in children with cancer compared with patients without cancer. The pathogens isolated were mainly Gram-positive bacteria, in particular Staphylococcus spp., which should be taken into account for empirical antimicrobial therapy.

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.

Advances in CSF shunt devices and their assessment for the treatment of hydrocephalus

INTRODUCTION

Hydrocephalus is a neurological disorder caused by excessive accumulation of the cerebrospinal fluid (CSF) in the ventricles of the brain. It can be treated by diverting the extra fluid to different parts of the body using a device called a shunt. This paper reviews different shunt devices that are used for this purpose.

AREAS COVERED

Shunts have high failure rates either due to infection or mechanical failure, therefore there is still ongoing work to address these two main handicaps. They require additional devices for performance assessment. Here, the paper also reviews different approaches for assessing shunt limitations. Moreover, future prospects are also discussed.

EXPERT OPINION

This study shows that shunt devices still remain an important treatment option for hydrocephalus. However, further efforts are required to design more advanced shunts, to eliminate high failure rates in clinical use. Sophisticated sensor systems that can accurately detect and regulate changes in CSF drainage to optimize drainage for individual needs. Moreover, shunt infection problem is still present despite recent improvements such as antibiotic impregnated catheters.

Effect of a bundle approach on external ventricular drain-related infection

BACKGROUND

Emergency placement of an external ventricular drain (EVD) is one of the most frequently performed neurosurgical procedures. EVD-related infection continues to be a major challenge causing significant morbidity and costs. Bundle approaches have been shown to reduce infection rates; however, they are still not widely used, and observation periods often were rather short.

METHODS

The present study evaluated the effect of a multi-item bundle approach for EVD placement and care on the occurrence of EVD-related infection. A before/after approach was used to compare groups of consecutive patients over 5-year epochs to control for bias and secondary confounding variables.

RESULTS

The number of patients in the group before implementation of the bundle approach was 141 and 208 thereafter. There were no statistical differences in demographic and other variables. While 41/141 patients (29.1%) had an EVD-related infection before, this was the case in only 10/208 patients (4.8%) thereafter (p < 0.0001). The EVD-related infection rate was reduced from 13.7/1000 catheter days to 3.2/1000, and the 50% probability of an EVD-related infection in correlation to the mean duration of EVD placement was significantly lower (p < 0.0001). Routine EVD replacement was not helpful to reduce EVD-related infection. EVD-related infection rates remained low also over the next 8 years after the study was finished.

CONCLUSIONS

The introduction of a multi-item bundle approach for EVD insertion and care resulted in a marked reduction of EVD-related infection. Long observation periods over 5 years and beyond confirm that short-term changes are sustained with continued use of such protocols.

A Systematic Review of Studies Reporting Antibiotic Pharmacokinetic Data in the Cerebrospinal Fluid of Critically Ill Patients with Uninflamed Meninges

Ventriculostomy-associated infections in critically ill patients remain therapeutically challenging because of drug- and disease-related factors that contribute to suboptimal antibiotic concentrations in cerebrospinal fluid. Optimal antibiotic dosing for the treatment and prevention of such infections should be based on robust and contextually specific pharmacokinetic data. The objects of this study were to describe and critically appraise studies with reported antibiotic concentrations or pharmacokinetic data in cerebrospinal fluid of critically ill patients without meningeal inflammation. We systematically reviewed the literature to identify published reports and studies describing antibiotic concentrations, pharmacokinetics, and pharmacokinetics/pharmacodynamics in cerebrospinal fluid of critically ill patients with uninflamed meninges. Fifty-eight articles met the inclusion criteria. There was significant heterogeneity in methodologies and results. When available, antibiotic pharmacokinetic parameters displayed large intersubject variability. Intraventricular dosing achieved substantially higher antibiotic concentrations in cerebrospinal fluid than did intravenous doses. Few studies conducted a robust pharmacokinetic analysis and described relevant clinical pharmacokinetic/pharmacodynamic indices and exposure targets in cerebrospinal fluid. Robust and clinically relevant antibiotic pharmacokinetic data describing antibiotic disposition in cerebrospinal fluid are necessary. Such studies should use a standardized approach to accurately describe pharmacokinetic variability. These data should ideally be tied to clinical outcomes whereby therapeutic targets in the cerebrospinal fluid can be better defined. Altered dosing strategies, in conjunction with exploring the utility of therapeutic drug monitoring, can then be developed to optimize antibiotic exposure with the goal of improving outcomes in this difficult-to-treat patient group.

Antibiotic Distribution into Cerebrospinal Fluid: Can Dosing Safely Account for Drug and Disease Factors in the Treatment of Ventriculostomy-Associated Infections?

Ventriculostomy-associated infections, or ventriculitis, in critically ill patients are associated with considerable morbidity. Efficacious antibiotic dosing for the treatment of these infections may be complicated by altered antibiotic concentrations in the cerebrospinal fluid due to variable meningeal inflammation and antibiotic properties. Therefore, doses used to treat infections with a higher degree of meningeal inflammation (such as meningitis) may often fail to achieve equivalent exposures in patients with ventriculostomy-associated infections such as ventriculitis. This paper aims to review the disease burden, infection rates, and common pathogens associated with ventriculostomy-associated infections. This review also seeks to describe the disease- and drug-related factors that influence antibiotic distribution into cerebrospinal fluid and provide a critical appraisal of current dosing of antibiotics commonly used to treat these types of infections. A Medline search of relevant articles was conducted and used to support a review of cerebrospinal fluid penetration of vancomycin, including critical appraisal of the recent paper by Beach et al. recently published in this journal. We found that in the intensive care unit, ventriculostomy-associated infections are the most common and serious complication of external ventricular drain insertion and often result in prolonged patient stay and increased healthcare costs. Reported infection rates are extremely variable (between 0 and 45%), hindered by the inherent diagnostic difficulty. Both Gram-positive and Gram-negative organisms are associated with such infections and the rise of multi-drug-resistant pathogens means that effective treatment is an ongoing challenge. Disease factors that may need to be considered are reduced meningeal inflammation and the presence of critical illness; drug factors include physiochemical properties, degree of plasma-protein binding, and affinity to active transporter proteins present in the blood-cerebrospinal fluid barrier. The relationship between cerebrospinal fluid antibiotic exposures in the setting of ventriculostomy-associated infection and clinical response has not been fully elucidated for many of the antibiotics commonly used in its treatment. More thorough and clinically relevant investigations are needed to better define blood pharmacokinetic/pharmacodynamics targets and optimal therapeutic exposures for treatment of ventriculostomy-associated infections. It is hoped that this future research will be able to provide clearer recommendations for clinicians frequently faced with dosing-related dilemmas when treating patients with these challenging infections.

Modalities and accuracy of diagnosis of external ventricular drainage-related infections: a prospective multicentre observational cohort study

BACKGROUND

Device infection is a major complication of placement external ventricular drains (EVD). Diagnostic features are often masked by underlying disease or cerebrospinal fluid (CSF) contamination by blood. We aim to assess which diagnostic modalities are applied for EVD-related infection (ERI) diagnosis and evaluate their accuracy.

METHODS

This observational prospective study included 187 adult patients with an EVD. Modalities of clinical diagnosis of ERI diagnosed by treating physicians on clinical grounds and blood and CSF analysis (clinically diagnosed ERI (CD-ERI)) were assessed prospectively. Additionally, the diagnostic accuracy of clinical and laboratory parameters for the diagnosis of culture proven ERI (CP-ERI) was evaluated, using data of the study patients and including a retrospective cohort of 39 patients with CP-ERI.

RESULTS

Thirty-one CD-ERIs were diagnosed in the prospective cohort. Most physicians used CSF analysis to establish the diagnosis. ROC analysis revealed an AUC of 0.575 (p = 0.0047) for the number of positive SIRS criteria and AUC of 0.5420 (p = 0.11) for the number of pathological neurological signs for diagnosis of CP-ERI. Diagnostic accuracy of laboratory values was AUC 0.596 (p = 0.0006) for serum white blood cell count (WBCC), AUC 0.550 (p = 0.2489) for serum C-reactive protein, AUC 0.644 (p < 0.0001) for CSF WBCC and AUC 0.690 for CSF WBC/red blood cell count ratio (both p < 0.0001). Neither a temporal trend in potential predictors of CP-ERI nor a correlation between clinical diagnosis and proven CSF infection was found.

CONCLUSIONS

Clinicians base their diagnosis of ERI mostly on CSF analysis and occurrence of fever, leading to over-diagnosis. The accuracy of the clinical diagnosis is low. Commonly used clinical and laboratory diagnostic criteria have a low sensitivity and specificity for ERI.

Recurrent sampling and ventriculostomy-associated infections: a case-control study

BACKGROUND

External ventricular drain (EVD) insertion is a common neurosurgical procedure with a significant risk of ventriculostomy-associated infections (VAIs), other morbidities and mortality. Several risk factors have been identified but their effect is unclear.

OBJECTIVE

Our primary objective was to assess whether recurrent EVD sampling increased the risk of VAIs. The secondary objective was to explore the effect of sampling frequency, duration of EVD stay, presence of cerebrospinal fluid leak and concurrent infections.

METHODS

Ours was a retrospective, single-centre, age-matched, case control study of 83 patients and 249 controls who underwent EVD insertion between 1 January 2010 - 31 December 2016. Patients with primary CNS infections, age under 1 year and death within 5 days of EVD insertion were excluded. Blinded abstractors collected all patient data through the electronic patient record system and regression analysis was used to compare the two groups.

RESULTS

Sampling the EVD more than once did not increase the risk of infection (OR 0.47, 95% CI 0.27-0.83, p = 0.01). Risk factors significantly associated with VAI included CSF leak (OR 2.06, 95% CI 1.16-3.67, p = 0.01), concurrent infection (OR 1.85, 95% CI 1.09-3.16, p = 0.02), and an EVD duration of >10 days (OR 2.28, 95% CI 1.24-4.18, p = 0.01).

CONCLUSION

Our findings do not support the notion that increased sampling of EVDs is associated with a higher risk of VAI. CSF leaks, concurrent infection and long-term EVDs are also statistically significant risk factors for infection.

Comparing External Ventricular Drains-Related Ventriculitis Surveillance Definitions

OBJECTIVE To evaluate the agreement between the current National Healthcare Safety Network (NHSN) definition for ventriculitis and others found in the literature among patients with an external ventricular drain (EVD) DESIGN Retrospective cohort study from January 2009 to December 2014 SETTING Neurology and neurosurgery intensive care unit of a large tertiary-care center PATIENTS Patients with an EVD were included. Patients with an infection prior to EVD placement or a permanent ventricular shunt were excluded. METHODS We reviewed the charts of patients with positive cerebrospinal fluid (CSF) cultures and/or abnormal CSF results while they had an EVD in place and applied various ventriculitis definitions. RESULTS We identified 48 patients with a total of 52 cases of ventriculitis (41 CSF culture-positive cases and 11 cases based on abnormal CSF test results) using the NHSN definition. The most common organisms causing ventriculitis were gram-positive commensals (79.2%); however, 45% showed growth of only 1 colony on 1 piece of media. Approximately 60% of the ventriculitis cases by the NHSN definition met the Honda criteria, approximately 56% met the Gozal criteria, and 23% met Citerio's definition. Cases defined using Honda versus Gozal definitions had a moderate agreement (κ=0.528; P<.05) whereas comparisons of Honda versus Citerio definitions (κ=0.338; P<.05) and Citerio versus Gozal definitions (κ=0.384; P<.05) had only fair agreements. CONCLUSIONS The agreement between published ventriculostomy-associated infection (VAI) definitions in this cohort was moderate to fair. A VAI surveillance definition that better defines contaminants is needed for more homogenous application of surveillance definitions between institutions and better comparison of rates. Infect Control Hosp Epidemiol 2017;38:574-579.

Outcome of ventriculoperitoneal shunt and predictors of shunt revision in infants with posthemorrhagic hydrocephalus

OBJECT

Ventriculoperitoneal (VP) shunts in infants with posthemorrhagic hydrocephalus (PHH) are prone to failures, with some patients at risk for multiple revisions. The objective of our study is to observe long-term outcomes and identify factors leading to proximal and distal multiple failures.

METHODS

We performed a retrospective review of infants with PHH that required VP shunt placement between 1982 and 2014. These patients were monitored clinically and radiographically after VP shunt placement.

RESULTS

A total of 502 surgical procedures (initial shunt insertion and revisions) were performed, with 380 shunt revisions in 102 (84 %) patients. Median shunt survival time was 54 months (0.03-220 months). Shunt survival was significantly affected by the following factors: intraventricular hemorrhage (IVH, grade II-III, 95 months vs. grade IV, 28 months, p = 0.022), birth weight (<1.5 kg, 59 months vs. >1.5 kg, 22 months, p = 0.005), gestational age (>27 weeks, 90 months vs. <27 weeks, 20 months, p < 0.0001), distal vs. proximal revision (133 months vs. 48 months, p = 0.013), obstruction (yes, 78 months vs. no, 28 months, p = 0.007), and infection (no, 75 months vs. yes, 39 months, p = 0.045). Regression analysis revealed that multiple gestation, head circumference (>27 cm), congenital anomalies, infection, and obstruction increased the proximal and distal shunt malfunction.

CONCLUSION

Long-term outcome of VP shunt placement in infants revealed a relatively high rate of complications requiring shunt revision as late as 30 years after initial placement. Infants with VP shunts should be monitored lifelong of these patients by neurosurgeons.

Current practice of external ventricular drainage: a survey among neurosurgical departments in Germany

BACKGROUND

There are various recommendations, but no generally accepted guidelines, to reduce the risk of external ventricular drainage (EVD)-associated infections. The primary objective of the present study was to evaluate the current practice of EVD in a European country and to set the results in perspective to published data.

METHOD

A standardised questionnaire prepared by the Commission of Technical Standards and Norms of the German Society of Neurosurgery was sent to 127 neurosurgical units in Germany.

RESULTS

Data were analysed from 99 out of 127 neurosurgical units which had been contacted. Overall, more than 10,000 EVD procedures appear to be performed in Germany annually. There is disagreement about the location where the EVD is inserted, and most EVDs are still inserted in the operation theatre. Most units apply subcutaneous tunnelling. Impregnated EVD catheters are used regularly in only about 20 % of units. Single-shot antibiotic prophylaxis is given in more than half of the units, while continued antibiotic prophylaxis is installed in only 15/99 units at a regular basis. There are discrepancies in the management of prolonged EVD use with regard to replacement policies. Regular cerebrospinal fluid (CSF) sampling is still performed widely. There were no statistical differences in policies with regard to academic versus non-academic units.

CONCLUSIONS

This survey clearly shows that some newer recommendations drawn from published studies penetrate much slower into clinical routine, such as the use of impregnated catheters, for example. It remains unclear how different policies actually impact quality and outcome in daily routine.

Ventriculostomy-related infections: The performance of different definitions for diagnosing infection

INTRODUCTION

Comparison of rates of ventriculostomy-related infections (VRIs) across institutions is difficult due to the lack of a standard definition. We sought to review published definitions of VRI and apply them to a test cohort to determine the degree of variability in VRI diagnosis.

MATERIALS AND METHODS

We conducted a PubMed search for definitions of VRI using the search strings "ventriculostomy-related infection" and "ventriculostomy-associated infection." We applied these definitions to a test cohort of 18 positive cerebrospinal fluid (CSF) cultures taken from ventriculostomies at two institutions to compare the frequency of infection using each definition.

RESULTS

We found 16 unique definitions of VRI. When the definitions were applied to the test cohort, the frequency of infection ranged from 22 to 94% (median 61% with interquartile range (IQR) 56-74%). The concordance between VRI diagnosis and treatment with VRI-directed antibiotics for at least seven days ranged from 56 to 89% (median: 72%, IQR: 71-78%).

CONCLUSIONS

The myriad of definitions in the literature produce widely different frequencies of infection. In order to compare rates of VRI between institutions for the purposes of qualitative metrics and research, a consistent definition of VRI is needed.

Periventricular hyperintensity in children with hydrocephalus

BACKGROUND

Magnetic resonance images of children with hydrocephalus often include a rim of hyperintensity in the periventricular white matter (halo).

OBJECTIVE

The purpose of this study was to decide between the hypothesis that the halo is caused by cerebrospinal fluid (CSF) flow during the cardiac cycle, and the alternate hypothesis that the halo is caused by anatomical changes (stretching and compression of white matter).

MATERIALS AND METHODS

Participants were selected from a multicenter imaging study of pediatric hydrocephalus. We compared 19 children with hydrocephalus to a group of 52 controls. We quantified ventricle enlargement using the frontal-occipital horn ratio. We conducted qualitative and quantitative analysis of diffusion tensor imaging in the corpus callosum and posterior limb of the internal capsule. Parameters included the fractional anisotropy (FA), mean diffusivity, axial diffusivity and radial diffusivity.

RESULTS

The halo was seen in 16 of the 19 children with hydrocephalus but not in the controls. The corpus callosum of the hydrocephalus group demonstrated FA values that were significantly decreased from those in the control group (P = 4 · 10(-6)), and highly significant increases were seen in the mean diffusivity and radial diffusivity in the hydrocephalus group. In the posterior limb of the internal capsule the FA values of the hydrocephalus group were higher than those for the control group (P = 0.002), and higher values in the hydrocephalus group were also noted in the axial diffusivity. We noted correlations between the diffusion parameters and the frontal-occipital horn ratio.

CONCLUSION

Our results strongly support the hypothesis that the halo finding in hydrocephalus is caused by structural changes rather than pulsatile CSF flow.

Antimicrobial-impregnated and -coated shunt catheters for prevention of infections in patients with hydrocephalus: a systematic review and meta-analysis

OBJECT The aim of this study was to evaluate the effectiveness of antimicrobial-impregnated and -coated shunt catheters (antimicrobial catheters) in reducing the risk of infection in patients undergoing CSF shunting or ventricular drainage. METHODS The PubMed and Scopus databases were searched. Catheter implantation was classified as either shunting (mainly ventriculoperitoneal shunting) or ventricular drainage (mainly external [EVD]). Studies evaluating antibioticimpregnated catheters (AICs), silver-coated catheters (SCCs), and hydrogel-coated catheters (HCCs) were included. A random effects model meta-analysis was performed. RESULTS Thirty-six studies (7 randomized and 29 nonrandomized, 16,796 procedures) were included. The majority of data derive from studies on the effectiveness of AICs, followed by studies on the effectiveness of SCCs. Statistical heterogeneity was observed in several analyses. Antimicrobial shunt catheters (AICs, SCCs) were associated with lower risk for CSF catheter-associated infections than conventional catheters (CCs) (RR 0.44, 95% CI 0.35-0.56). Fewer infections developed in the patients treated with antimicrobial catheters regardless of randomization, number of participating centers, funding, shunting or ventricular drainage, definition of infections, de novo implantation, and rate of infections in the study. There was no difference regarding gram-positive bacteria, all staphylococci, coagulase-negative streptococci, and Staphylococcus aureus, when analyzed separately. On the contrary, the risk for methicillin-resistant S. aureus (MRSA, RR 2.64, 95% CI 1.26-5.51), nonstaphylococcal (RR 1.75, 95% CI 1.22-2.52), and gram-negative bacterial (RR 2.13, 95% CI 1.33-3.43) infections increased with antimicrobial shunt catheters. CONCLUSIONS Based on data mainly from nonrandomized studies, AICs and SCCs reduce the risk for infection in patients undergoing CSF shunting. Future studies should evaluate the higher risk for MRSA and gram-negative infections. Additional trials are needed to investigate the comparative effectiveness of the different types of antimicrobial catheters.

Endovascular management of external ventricular drain-associated cerebrovascular injuries

Background:

Placement of external ventricular drains (EVDs) is a common, life-saving neurosurgical procedure indicated across a variety of settings. While advances have made the procedure quite safe, the potential for iatrogenic morbidity and mortality continues. We document our experience with the endovascular management of three pseudoaneurysms associated with EVD placement and discuss the endovascular treatment options for EVD-associated cerebrovascular injury.

Methods:

We performed a retrospective analysis to identify all EVDs placed from 2008 through 2013 at our institution. In instances of EVD-associated cerebrovascular injury, all admission and subsequent radiographic studies were reviewed, including cerebral angiograms and computed tomography (CT) scans where available. Angiograms were reviewed to record the extent of vascular injury and outcomes after treatment.

Results:

One female and two male patients (age range, 40-75 years) were found to have developed vascular injuries associated with EVD placement. Three pseudoaneurysms, of the posterior communicating artery (PCOM), pericallosal artery branch, and the middle meningeal artery, respectively, were treated by coil and/or glue embolization.

Conclusions:

Although EVD-associated cerebrovascular injury remains a rare phenomenon, such procedures are not entirely benign. Endovascular repair for such lesions proves a viable, effective option.

Proteins, platelets, and blood coagulation at biomaterial interfaces

Blood coagulation and platelet adhesion remain major impediments to the use of biomaterials in implantable medical devices. There is still significant controversy and question in the field regarding the role that surfaces play in this process. This manuscript addresses this topic area and reports on state of the art in the field. Particular emphasis is placed on the subject of surface engineering and surface measurements that allow for control and observation of surface-mediated biological responses in blood and test solutions. Appropriate use of surface texturing and chemical patterning methodologies allow for reduction of both blood coagulation and platelet adhesion, and new methods of surface interrogation at high resolution allow for measurement of the relevant biological factors.

Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 8: Management of cerebrospinal fluid shunt infection

OBJECT

The objective of this systematic review was to answer the following question: What is the optimal treatment strategy for CSF shunt infection in pediatric patients with hydrocephalus?

METHODS

The US National Library of Medicine and the Cochrane Database of Systematic Reviews were queried using MeSH headings and key words relevant to the objective of this systematic review. Abstracts were reviewed, after which studies meeting the inclusion criteria were selected and graded according to their quality of evidence (Classes I-III). Evidentiary tables were constructed that summarized pertinent study results, and based on the quality of the literature, recommendations were made (Levels I-III).

RESULTS

A review and critical appraisal of 27 studies that met the inclusion criteria allowed for a recommendation for supplementation of antibiotic treatment using partial (externalization) or complete shunt hardware removal, with a moderate degree of clinical certainty. However, a recommendation regarding whether complete shunt removal is favored over partial shunt removal (that is, externalization) could not be made owing to severe methodological deficiencies in the existing literature. There is insufficient evidence to recommend the use of intrathecal antibiotic therapy as an adjunct to systemic antibiotic therapy in the management of routine CSF shunt infections. This also holds true for other clinical scenarios such as when an infected CSF shunt cannot be completely removed, when a shunt must be removed and immediately replaced in the face of ongoing CSF infection, or when the setting is ventricular shunt infection caused by specific organisms (for example, gram-negative bacteria).

CONCLUSIONS

Supplementation of antibiotic treatment with partial (externalization) or complete shunt hardware removal are options in the management of CSF shunt infection. There is insufficient evidence to recommend either shunt externalization or complete shunt removal as the preferred surgical strategy for the management of CSF shunt infection. Therefore, clinical judgment is required. In addition, there is insufficient evidence to recommend the combination of intrathecal and systemic antibiotics for patients with CSF shunt infection when the infected shunt hardware cannot be fully removed, when the shunt must be removed and immediately replaced, or when the CSF shunt infection is caused by specific organisms. The potential neurotoxicity of intrathecal antibiotic therapy may limit its routine use.

RECOMMENDATION

Supplementation of antibiotic treatment with partial (externalization) or with complete shunt hardware removal is an option in the management of CSF shunt infection.

STRENGTH OF RECOMMENDATION

Level II, moderate degree of clinical certainty.

RECOMMENDATION

There is insufficient evidence to recommend either shunt externalization or complete shunt removal as a preferred surgical strategy for the management of CSF shunt infection. Therefore, clinical judgment is required.

STRENGTH OF RECOMMENDATION

Level III, unclear degree of clinical certainty.

RECOMMENDATION

There is insufficient evidence to recommend the combination of intrathecal and systemic antibiotics for patients with CSF shunt infection in whom the infected shunt hardware cannot be fully removed or must be removed and immediately replaced, or when the CSF shunt infection is caused by specific organisms. The potential neurotoxicity of intrathecal antibiotic therapy may limit its routine use.

STRENGTH OF RECOMMENDATION

Level III, unclear degree of clinical certainty.

Intraventricular or intrathecal colistin for the treatment of central nervous system infections caused by multidrug-resistant Gram-negative bacteria

Central nervous system infections caused by Gram-negative bacteria susceptible only to colistin are rare but life-threatening and increasing in prevalence. Given the current antibiotic development pipeline it is likely that the paucity of therapeutic options will continue for the next years. Colistin is an amphipathic bactericidal antibiotic which is administered systemically as colistin methanesulfonate (also known as colistimethate sodium). Colistin methanesulfonate is the inactive prodrug, and in cerebrospinal fluid undergoes spontaneous hydrolysis to colistin (the active form with antimicrobial activity). In this review, we describe and evaluate the clinical and experimental data supporting the use of intraventricular (IVT) or intrathecal (IT) colistin against multidrug-resistant Gram-negative infections of the central nervous system, describe the permeability of the blood-brain barrier to colistin, the pharmacokinetics of colistin after IVT administration of colistin methanesulfonate, its anti-endotoxin activity, discuss the opportunity to administer colistin intraventricularly or intrathecally and the dose regimen, and provide recommendations based on the available evidence.

Central Nervous System Infections

Central nervous system (CNS) infections—i.e., infections involving the brain (cerebrum and cerebellum), spinal cord, optic nerves, and their covering membranes—are medical emergencies that are associated with substantial morbidity, mortality, or long-term sequelae that may have catastrophic implications for the quality of life of affected individuals. Acute CNS infections that warrant neurointensive care (ICU) admission fall broadly into three categories—meningitis, encephalitis, and abscesses—and generally result from blood-borne spread of the respective microorganisms. Other causes of CNS infections include head trauma resulting in fractures at the base of the skull or the cribriform plate that can lead to an opening between the CNS and the sinuses, mastoid, the middle ear, or the nasopharynx. Extrinsic contamination of the CNS can occur intraoperatively during neurosurgical procedures. Also, implanted medical devices or adjunct hardware (e.g., shunts, ventriculostomies, or external drainage tubes) and congenital malformations (e.g., spina bifida or sinus tracts) can become colonized and serve as sources or foci of infection. Viruses, such as rabies, herpes simplex virus, or polioviruses, can spread to the CNS via intraneural pathways resulting in encephalitis. If infection occurs at sites (e.g., middle ear or mastoid) contiguous with the CNS, infection may spread directly into the CNS causing brain abscesses; alternatively, the organism may reach the CNS indirectly via venous drainage or the sheaths of cranial and spinal nerves. Abscesses also may become localized in the subdural or epidural spaces. Meningitis results if bacteria spread directly from an abscess to the subarachnoid space. CNS abscesses may be a result of pyogenic meningitis or from septic emboli associated with endocarditis, lung abscess, or other serious purulent infections. Breaches of the blood–brain barrier (BBB) can result in CNS infections. Causes of such breaches include damage (e.g., microhemorrhage or necrosis of surrounding tissue) to the BBB; mechanical obstruction of microvessels by parasitized red blood cells, leukocytes, or platelets; overproduction of cytokines that degrade tight junction proteins; or microbe-specific interactions with the BBB that facilitate transcellular passage of the microorganism. The microorganisms that cause CNS infections include a wide range of bacteria, mycobacteria, yeasts, fungi, viruses, spirochaetes (e.g., neurosyphilis), and parasites (e.g., cerebral malaria and strongyloidiasis). The clinical picture of the various infections can be nonspecific or characterized by distinct, recognizable clinical syndromes. At some juncture, individuals with severe acute CNS infections require critical care management that warrants neuro-ICU admission. The implications for CNS infections are serious and complex and include the increased human and material resources necessary to manage very sick patients, the difficulties in triaging patients with vague or mild symptoms, and ascertaining the precise cause and degree of CNS involvement at the time of admission to the neuro-ICU. This chapter addresses a wide range of severe CNS infections that are better managed in the neuro-ICU. Topics covered include the medical epidemiology of the respective CNS infection; discussions of the relevant neuroanatomy and blood supply (essential for understanding the pathogenesis of CNS infections) and pathophysiology; symptoms and signs; diagnostic procedures, including essential neuroimaging studies; therapeutic options, including empirical therapy where indicated; and the perennial issue of the utility and effectiveness of steroid therapy for certain CNS infections. Finally, therapeutic options and alternatives are discussed, including the choices of antimicrobial agents best able to cross the BBB, supportive therapy, and prognosis.

Decreasing ventricular infections through the use of a ventriculostomy placement bundle: experience at a single institution

Object

Ventricular infection after ventriculostomy placement carries a high mortality rate. Responding to ventriculostomy infection rates, a multidisciplinary performance improvement team was formed, a comprehensive protocol for ventriculostomy placement was developed, and the efficacy was evaluated.

Methods

A best-practice protocol was developed, including hand hygiene before the procedure; prophylactic antibiotics; sterile gloves changed between preparation, draping, and procedure; hair removal by clipping for dressing adherence; skin preparation using iodine povacrylex (0.7% available iodine) and isopropyl alcohol (74%); full body and head drape; full surgical attire for the surgeon and other bedside providers; and an antimicrobial-impregnated catheter. A checklist of critical components was used to confirm proper insertion and to monitor practice. Procedure-specific infection rates were calculated using the number of infections divided by the number of patients in whom an external ventricular drainage (EVD) device was inserted × 100 (%). Data were reported back to providers and to the committee. Bundle compliance was monitored over a 4-year period.

Results

At the authors' institution, 2928 ventriculostomies were performed between the beginning of the fourth quarter of 2006 and the end of the first quarter of 2012. Although the best-evidence bundle was applied to all patients, only 588 (20.1%) were checklist monitored (increasing from 7% to 23% over the study period). The infection rate for the 2 quarters before bundle implementation was 9.2%. During the study period, the rate decreased quarterly to 2.6% and then to 0%. Over a 4-year period, the rate was 1.06% (2007), 0.66% (2008), 0.15% (2009), and 0.34% (2010); it was 0% in 2011 and the first quarter of 2012. The overall EVD infection rate was 0.46% after bundle implementation.

Conclusions

Bundle implementation including an antimicrobial-impregnated catheter dramatically decreased EVD-related infections. Training and situational awareness of appropriate practice, assisted by the checklist, plus use of the antibiotic-impregnated catheter resulted in sustained reduction in ventriculitis.

Abnormal head movement in a patient with tuberculous meningitis

The bobble-head doll syndrome is characterised by abnormal head movements. These head movements are usually 'yes-yes' (up and down) type; rarely, head movements are 'no-no' (side-to-side) type. Commonly described causes of the bobble-head doll syndrome include third ventricular tumours, suprasellar arachnoid cysts, aqueductal stenosis and other lesions in the region of the third ventricle of the brain. We report a case of tuberculous meningitis with hydrocephalus; in this patient bobble-head doll syndrome developed following external ventricular drainage. In our patient, placement of intraventricular drain led to massive dilatation of the frontal horn of the left lateral ventricle because of blocked foramina of Monro on the left side. The bobble-head doll syndrome, presumably, developed because of the pressure effect of the dilated third ventricle on the dorsomedial nucleus of the thalamus, red nucleus and dentatorubrothalamic pathways. We think that distortion of the third ventricle was responsible for the impairment of the functions of all these structures.