Duration of In Vivo Antimicrobial Activity of Antibiotic-impregnated Cerebrospinal Fluid Catheters

Antibiotic-Impregnated Ventriculoperitoneal Shunts Decrease Bacterial Shunt Infection: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Antibiotic-impregnated shunts seem to be beneficial in preventing bacterial infections and decreasing mortality by effectively inhibiting microbial growth in the shunt system and reducing the risk of shunt-associated infections. This study aimed to evaluate the efficacy of antibiotic-impregnated shunt catheters (AISC) in reducing the incidence of bacterial shunt infection in patients with hydrocephalus.

METHODS

The protocol was registered on PROSPERO. A meta-analysis was conducted by searching 3 databases (PubMed, Scopus, CENTRAL) for relevant randomized controlled trials and observational studies. We included all studies published until November 2022 in any language. The primary outcome was the rate of bacterial infections, whereas the rate of shunt failure was our secondary endpoint. Odds ratios (OR) with 95% CI were calculated using a random-effects model.

RESULTS

A total of 27 articles with 27 266 shunt operations were included in this study. The results indicated that using AISC is significantly associated with reduction in infections (OR = 0.42; 95% CI: 0.33-0.54). Regarding shunt failure, there was a tendency in favor of AISC use (OR = 0.73; 95% CI: 0.51-1.06).

CONCLUSION

Our study provided evidence that AISC is significantly associated with the reduction in the rate of bacterial ventriculoperitoneal-shunt infection. In addition, there was a tendency toward AISC to decrease shunt failure compared with the standard shunt.

Prevention of Ventriculostomy Related Infection: Effectiveness of Impregnated Biomaterial

External ventricular drain(EVD) exposes the patient to infectious complications which are associated with significant morbidity and economic burden. Biomaterials impregnated with various antimicrobial agents have been developed to decrease the rate of bacterial colonization and subsequent infection. While promising, antibiotics and silver-impregnated EVD showed conflicting clinical results. The aim of the present review is to discuss the challenges associated with the development of antimicrobial EVD catheters and their effectiveness from the bench to the bedside.

Actions of N-acetylcysteine, daptomycin, vancomycin, and linezolid on methicillin-resistant Staphylococcus aureus biofilms in the ventriculoperitoneal shunt infections: an experimental study

Background

Shunt systems are used to provide cerebrospinal fluid drainage in the treatment of hydrocephalus. Recently, antibiotic-impregnated shunt systems are used to prevent colonization in the ventriculoperitoneal catheters. Methicillin-resistant Staphylococcus aureus (MRSA) is the most common causative microorganism of shunt infections. The aim of the study is to investigate effects of several substances on MRSA biofilms in the ventriculoperitoneal catheters.

Methods

The present study consists of mainly eight groups (each has two subgroups as antibiotic-impregnated and nonantibiotic-impregnated catheters). In addition, each group contains six molds using MRSA strains. In this study, daptomycin (DAPT) (2 mg/ml), vancomycin (VAN) (10 mg/ml), linezolid (LIN) (2 mg/ml), N-acetylcysteine (NAC) (6 mg/ml), and various combinations of these substances were used to evaluate the treatment against MRSA using scanning electron microscope (SEM) images and microbiological enumeration.

Results

The colony count in the antibiotic-impregnated samples significantly decreased compared to nonantibiotic-impregnated samples in the MRSA, MRSA + DAPT, and MRSA + LIN groups (p < 0.01), respectively. Conversely, the colony count in antibiotic-impregnated samples significantly increased compared to nonantibiotic-impregnated samples in NAC + DAPT and NAC + VAN groups (p < 0.01), respectively.

Conclusions

The results showed that the use of antibiotic-impregnated catheters has a significant impact on the prevention of infection whereas the combination of NAC and DAPT showed better antibiofilm and antibacterial effects than other combinations on the prevention and treatment of nonantibiotic-impregnated catheter infections.

In vitro study of factors influencing the duration of antimicrobial protection of antimicrobial-impregnated external ventricular drains

BACKGROUND

In vitro and clinical studies assessing the duration of the protective activity of antimicrobial-impregnated external ventricular drains (AI-EVDs) gave conflicting results.

OBJECTIVES

To identify factors associated with decreased antimicrobial activity of AI-EVDs that were not taken into account in previous in vitro models.

METHODS

We performed in vitro experiments with Bactiseal™ AI-EVDs, under different conditions. Tested parameters were chosen to mimic conditions in which AI-EVDs are used: perfusion by saline (at different flow rates) or not perfused, dwelling medium (air, saline, saline+protein, lipid) and temperature. Antimicrobial activity was assessed by measurement of inhibitory diameters of a 0.5 cm portion of an AI-EVD (cut every 2 days) placed onto agar plates covered by a standardized Staphylococcus spp. inoculum (three different isolates). MS was used to measure concentrations of rifampicin and clindamycin after 48 h of dwelling.

RESULTS

In univariate analysis, most of the tested factors were associated with reduced antimicrobial activity: liquid media (as compared with ambient air), perfusion whatever the rate flow (as compared with no perfusion) and presence of protein in the media. In multivariate analysis, dwelling in media (lipid or saline) was the most constantly associated with a reduction of inhibition diameters (P < 0.01), as compared with ambient air. After 48 h of dwelling, the clindamycin concentration was higher than 100 and 450 mg/L in saline and saline+BSA, respectively.

CONCLUSIONS

The medium in which an AI-EVD is dwelling plays a significant role in the duration of AI-EVD activity. These results may explain conflicting results between clinical and in vitro studies.

Systematic Review and Meta-Analysis of Antibiotic-Impregnated Shunt Catheters on Anti-Infective Effect of Hydrocephalus Shunt

OBJECTIVE

Shunt infection is a common complication while treating hydrocephalus. The antibiotic-impregnated shunt catheter (AISC) was designed to reduce shunt infection rate. A meta-analysis was conducted to study the effectiveness of AISCs in reduction of shunt infection in terms of age, follow-up time and high-risk patient population.

METHODS

This study reviewed literature from three databases including PubMed, EMBASE, and Cochrane Library (from 2000 to March 2019). Clinical studies from controlled trials for shunt operation were included in this analysis. A subgroup analysis was performed based on the patient's age, follow-up time and high-risk population. The fixed effect in RevMan 5.3 software (Cochrane Collaboration) was used for this meta-analysis.

RESULTS

This study included 19 controlled clinical trials including 10105 operations. The analysis demonstrated that AISC could reduce the infection rate in shunt surgery compared to standard shunt catheter (non-AISC) from 8.13% to 4.09% (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.40-0.58; p=0.01; I2=46%). Subgroup analysis of different age groups showed that AISC had significant antimicrobial effects in all three groups (adult, infant, and adolescent). Follow-up time analysis showed that AISC was effective in preventing early shunt infections (within 6 months after implant). AISC is more effective in high-risk population (OR, 0.24; 95% CI, 0.14-0.40; p=0.60; I2=0%) than in general patient population.

CONCLUSION

The results of meta-analysis indicated that AISC is an effective method for reducing shunt infection. We recommend that AISC should be considered for use in infants and high-risk groups. For adult patients, the choice for AISC could be determined based on the treatment cost.

Efficacy of antibiotic-impregnated shunt versus conventional shunts to reduce cerebrospinal fluid infections in children: A systematic review and meta-analysis

Hydrocephalus is among the most common pediatric conditions treated by neurosurgeons. An antibiotic-impregnated shunt (AIS) was designed to reduce the rate of shunt infections. The objective of this systematic review and meta-analysis was to assess the efficiency of AIS in reducing the rate of shunt infection compared with standard shunts (SSs). A systematic search of PubMed, EMBASE, Medline, Cochrane Library, TRIP Database, CINAHL and Google Scholar databases was performed. Eligible studies included observational studies and randomized controlled trials (RCT) that compared the effects of AIS and SS for preventing shunt infections in pediatric patients. Twelve observational studies and one RCT conducted from January 2005 through October 2019 involving 7,952 pediatric patients were included in the analysis. The use of AIS significantly decreased the risk of CRI [risk ratio (RR) 0.42; 95% confidence interval: 0.33 to 0.53; P<0.00001] with no statistical heterogeneity across the included studies (I²=42%). This analysis demonstrates that the use of AIS significantly reduces the risk of shunt infection in pediatric patients.

Natural history of ventriculostomy-related infection under appropriate treatment and risk factors of poor outcome: a retrospective study

OBJECTIVE

The authors aimed to describe the natural history of ventriculostomy-related infections (VRIs) under appropriate treatment and to assess risk factors for poor outcome.

METHODS

All patients older than 18 years in whom an external ventricular drain (EVD) had been implanted and who had developed a VRI requiring treatment were included in this retrospective study. D0 was defined as the first day of antibiotic administration. Clinical and biological parameters were compared each day beginning with D1 and ending with D10 to those of D0. The authors defined D0 in a control group as the day a CSF culture came back positive, without any sign of infection. The authors then searched for poor prognostic factors in the VRI group.

RESULTS

Among 567 patients requiring an EVD between January 2007 and October 2017, 39 developed a VRI. Most were monomicrobial infections, and 47 microbes were responsible (45% were gram-positive cocci). Clinical parameters differed significantly from the control group during the first 2 days and then returned to baseline. The CSF parameters differed significantly from the control group for a longer period, returning to baseline after 5 days. CSF sterilization occurred in a median time of 2 days. An intrathecal route or EVD exchange was not associated with a poor outcome. No clinical or biological parameter between D3 and D5 was linked to outcome.

CONCLUSIONS

Clinical status improved faster than CSF parameters (before and after D5, respectively). Some CSF parameters remained abnormal until D10. Body temperature and microbiological cultures normalized faster than other parameters.

Durability of antimicrobial activity of antibiotic-impregnated external ventricular drains: a prospective study

Background

Antibiotic-impregnated external ventricular drains (AI-EVDs) have a debated efficacy in clinical studies.

Objectives

Our aim was to assess the durability of antimicrobial activity of AI-EVDs used in clinical settings.

Methods

From April 2017 to January 2018, all consecutive AI-EVDs (Bactiseal™) inserted in adult patients were prospectively included. After removal, each AI-EVD was cultured and assessed for antimicrobial activity on both internal and external sides of AI-EVDs. Catheters were each challenged with a single Staphylococcus strain [MSSA, MRSA or methicillin-resistant Staphylococcus epidermidis (MRSE)]. MS was used to measure residual concentrations of rifampicin and clindamycin.

Results

Sixty-five AI-EVDs were included (56 patients). Among these, 21 were challenged with MSSA, 23 with MRSA and 21 with MRSE. Five ventriculostomy-related colonizations (9%) and two ventriculostomy-related infections (4%) occurred. Staphylococcus was the main bacterium responsible for colonization (4/5). AI-EVD inhibition decreased significantly against MRSA and MRSE according to duration of catheterization (for external and internal sides, P < 0.02) and overall volume of CSF drained (P < 0.005 for both sides against MRSE, P < 0.005 for external side against MRSA), but not against MSSA. Clindamycin concentration was not correlated with duration of catheterization or CSF volume drained, but <20% of initial concentration was recovered even after 5 days of AI-EVD dwelling. Conversely, rifampicin concentration showed a rapid and significant decline correlated to duration and CSF volume (P < 0.001 and P = 0.03, respectively).

Conclusions

Antimicrobial activity of AI-EVDs dropped quickly in vivo. Antimicrobial impregnation did not prevent AI-EVD colonization by susceptible strains in 9% of the cases.

Evaluation of an in vivo model for ventricular shunt infection: a pilot study using a novel antimicrobial-loaded polymer

OBJECTIVE

Ventricular shunt infection remains an issue leading to high patient morbidity and cost, warranting further investigation. The authors sought to create an animal model of shunt infection that could be used to evaluate possible catheter modifications and innovations.

METHODS

Three dogs underwent bilateral ventricular catheter implantation and inoculation with methicillin-sensitive Staphylococcus aureus (S. aureus). In 2 experimental animals, the catheters were modified with a polymer containing chemical "pockets" loaded with vancomycin. In 1 control animal, the catheters were polymer coated but without antibiotics. Animals were monitored for 9 to 11 days, after which the shunts were explanted. MRI was performed after shunt implantation and prior to catheter harvest. The catheters were sonicated prior to microbiological culture and also evaluated by electron microscopy. The animals' brains were evaluated for histopathology.

RESULTS

All animals underwent successful catheter implantation. The animals developed superficial wound infections, but no neurological deficits. Imaging demonstrated ventriculitis and cerebral edema. Harvested catheters from the control animal demonstrated > 104 colony-forming units (CFUs) of S. aureus. In the first experimental animal, one shunt demonstrated > 104 CFUs of S. aureus, but the other demonstrated no growth. In the second experimental animal, one catheter demonstrated no growth, and the other grew trace S. aureus. Brain histopathology revealed acute inflammation and ventriculitis in all animals, which was more severe in the control.

CONCLUSIONS

The authors evaluated an animal model of ventricular shunting and reliably induced features of shunt infection that could be microbiologically quantified. With this model, investigation of pathophysiological and imaging correlates of infection and potentially beneficial shunt catheter modifications is possible.

From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study

Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5–56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4–41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

Antibiotic-impregnated catheters reduce ventriculoperitoneal shunt infection rate in high-risk newborns and infants

PURPOSE

The incidence of ventriculoperitoneal (VP) shunt infection accounts for about 5-15%, but it can rise up to 70% in specific high-risk subgroups. Antibiotic-impregnated catheters (AICs) have been designed to reduce shunt infections, but reports on their efficacy are discordant, especially in young children. The aim of this study is to assess, for the first time, the efficacy of AICs in newborns and infants at very high risk for shunt infection.

METHODS

We reviewed the medical records of newborns and infants treated with a VP shunt for newly diagnosed hydrocephalus. Patients were divided in two groups: Group A was composed by children who received AICs, whereas Group B included children implanted with standard silicone catheters (non-AICs). We compared the shunt infection rate in both groups, and analyzed differences in specific high-risk subgroups (preterm newborns, children with posthemorrhagic or postinfective hydrocephalus, and children with a previous external ventricular drainage).

RESULTS

Forty eight children younger than 1 year old were included in our study. Twenty two patients were implanted with an AIC, whereas 26 patients received a standard silicone catheter. The follow-up was at least 1 year (mean 8 ± 3 years). The overall infection rate decreased from 34% in non-AIC group to 9 % in the AIC group. Moreover, AICs showed to have a protective effect against shunt infections in all the specific high-risk subgroups analyzed.

CONCLUSIONS

This study demonstrates for the first time that AICs are effective in reducing VP shunt infection in high-risk pediatric patients younger than 1 year old.

Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 7: Antibiotic-impregnated shunt systems versus conventional shunts in children: a systematic review and meta-analysis

OBJECT

The objective of this systematic review and meta-analysis was to answer the following question: Are antibiotic-impregnated shunts (AISs) superior to standard shunts (SSs) at reducing the risk of shunt infection in pediatric patients with hydrocephalus?

METHODS

Both the US National Library of Medicine PubMed/MEDLINE database and the Cochrane Database of Systematic Reviews were queried using MeSH headings and key words relevant to AIS use in children. Abstracts were reviewed, after which studies meeting the inclusion criteria were selected. An evidentiary table was assembled summarizing the studies and the quality of their evidence (Classes I-III). A meta-analysis was conducted using a random-effects model to calculate a cumulative estimate of treatment effect using risk ratio (RR). Heterogeneity was assessed using the chi-square and I(2) statistics. Based on the quality of the literature and the result of the meta-analysis, a recommendation was rendered (Level I, II, or III).

RESULTS

Six studies, all Class III, met our inclusion criteria. All but one study focused on a retrospective cohort and all but one were conducted at a single institution. Four of the studies failed to demonstrate a lowered infection rate with the use of an AIS. However, when the data from individual studies were pooled together, the infection rate in the AIS group was 5.5% compared with 8.6% in the SS group. Using a random-effects model, the cumulative RR was 0.51 (95% CI 0.29-0.89, p < 0.001), indicating that a shunt infection was 1.96 times more likely in patients who received an SS.

CONCLUSIONS

We recommend AIS tubing because of the associated lower risk of shunt infection compared to the use of conventional silicone hardware (quality of evidence: Class III; strength of recommendation: Level III).

RECOMMENDATION

Antibiotic-impregnated shunt (AIS) tubing may be associated with a lower risk of shunt infection compared with conventional silicone hardware and thus is an option for children who require placement of a shunt.

STRENGTH OF RECOMMENDATION

Level III, unclear degree of clinical certainty.

Effect of introduction of antibiotic-impregnated shunt catheters on cerebrospinal fluid shunt infection in children: a large single-center retrospective study

OBJECT

Infection after both primary and revision shunt surgeries remains a major problem in pediatric neurosurgical practice. Antibiotic-impregnated shunt (AIS) tubing has been proposed to reduce infection rates. The authors report their experience with AIS catheters in their large pediatric neurosurgery department.

METHODS

The authors conducted a retrospective case review of consecutive shunt operations performed before (1993-2003) and after (2005-2009) introduction of AIS tubing, with analysis of shunt infection rates and causative organisms identified.

RESULTS

The historical control group consisted of 1592 consecutive shunt operations (657 primary insertions), and the AIS study group consisted of 500 consecutive shunt operations (184 primary insertions). Patients ranged in age from 0-17 years. In the historical group, 135 infections were identified (8.4%). In the AIS study group, 25 infections were identified (5%), representing a significant reduction (p < 0.005). The latency to diagnosis of infection was 23 days in the historical group and 139 days in the AIS study group. The infection rates in infants 0-6 months of age were 12.2% (historical group) and 6.7% (AIS group, p < 0.005), and in infants 7-12 months of age the rates were 7.9% (historical group) and 2.7% (AIS group, p < 0.005). In the historical control group, the frequency rank order of causative organisms was coagulase-negative staphylococcus (51.9%), Staphylococcus aureus (31.6%), streptococcus or enterococcus spp. (8.8%), gram-negative organisms (4.4%), and Propionibacterium acnes (2.2%). Organisms responsible for infections in AIS were S. aureus (40%), followed by streptococcus or enterococcus spp. (20%), P. acnes and coagulase-negative staphylococcus (both 16%), and gram-negative organisms (4%). No unusually antibiotic-resistant bacteria were identified in either group. The authors further subdivided the AIS group into those undergoing primary AIS insertion (Subgroup 1), those undergoing revision of non-AIS systems using AIS components (Subgroup 2), and those undergoing revision of AIS systems using AIS components (Subgroup 3). Infection rates were 1.6% in Subgroup 1, 2.5% in Subgroup 2, and 11.7% in Subgroup 3. Staphylococcus aureus was the most common organism identified in infections of the Subgroups 2 and 3.

CONCLUSIONS

Use of AIS tubing significantly improves shunt infection rates in both general pediatric and infant populations with no evidence of increased antibiotic resistance, which is in agreement with previous studies. However, the increased infection rate in revision surgery in children with AIS catheters in situ raises questions about their long-term application.

Silver segregation and bacterial growth of intraventricular catheters impregnated with silver nanoparticles in cerebrospinal fluid drainages

OBJECTIVES

Intraventricular catheters impregnated with silver nanoparticles are developed to reduce catheter-associated infections in cerebrospinal fluid (CSF) drainages. Silver released from these new catheters should have an anti-microbacterial effect. This study examines the silver ion release and a potential effect of bacterial growth in an in vitro experiment.

METHODS

Seven original silver-coated ventricle catheters were rinsed thoroughly with an artificial CSF for 6 days. The collecting containers were replaced every 24 hours. In these samples, ion concentrations of silver were determined via trace analysis through atomic absorption spectroscopy. Furthermore, a bacterial growth was conducted on silver-impregnated and non-impregnated catheters.

RESULTS

In none of the samples, a concentration of silver ions could be detected. For Staphylococcus aureus, a slightly decreased bacterial growth could be observed with silver-impregnated catheters.

DISCUSSION

There is no risk of a toxic effect due to silver release into the CSF. However, the in vivo antibacterial effect has to be further investigated. We recommend clinical trials to prove the oligodynamic and anti-microbacterial effects of silver-impregnated ventricular catheters.

The efficacy of silver-embedded polypropylene-grafted polyethylene glycol-coated ventricular catheters on prevention of shunt catheter infection in rats

PURPOSE

Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g-PEG) copolymer and silver nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats.

METHODS

Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheter-embedded group; group 2, sterile PP-g-PEG-coated catheter group; group 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10 × 10(6) colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively.

RESULTS

Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0 ± 0, p < 0.001; 1.08 ± 0.18, p < 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33 ± 3.02, p < 0.001; 4.00 ± 0.68, p < 0.001, respectively).

CONCLUSIONS

The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma.

Antibiotic-impregnated shunt systems versus standard shunt systems: a meta- and cost-savings analysis

OBJECT

Infection is a serious and costly complication of CSF shunt implantation. Antibiotic-impregnated shunts (AISs) were introduced almost 10 years ago, but reports on their ability to decrease the infection rate have been mixed. The authors conducted a meta-analysis assessing the extent to which AISs reduce the rate of shunt infection compared with standard shunts (SSs). They also examined cost savings to determine the degree to which AISs could decrease infection-related hospital expenses.

METHODS

After conducting a comprehensive search of multiple electronic databases to identify studies that evaluated shunt type and used shunt-related infection as the primary outcome, 2 reviewers independently evaluated study quality based on preestablished criteria and extracted data. A random effects meta-analysis of eligible studies was then performed. For studies that demonstrated a positive effect with the AIS, a cost-savings analysis was conducted by calculating the number of implanted shunts needed to prevent a shunt infection, assuming an additional cost of $400 per AIS system and $50,000 to treat a shunt infection.

RESULTS

Thirteen prospective or retrospective controlled cohort studies provided Level III evidence, and 1 prospective randomized study provided Level II evidence. "Shunt infection" was generally uniformly defined among the studies, but the availability and detail of baseline demographic data for the control (SS) and treatment (AIS) groups within each study were variable. There were 390 infections (7.0%) in 5582 procedures in the control group and 120 infections (3.5%) in 3467 operations in the treatment group, yielding a pooled absolute risk reduction (ARR) and relative risk reduction (RRR) of 3.5% and 50%, respectively. The meta-analysis revealed the AIS to be statistically protective in all studies (risk ratio = 0.46, 95% CI 0.33-0.63) and in single-institution studies (risk ratio = 0.38, 95% CI 0.25-0.58). There was some evidence of heterogeneity when studies were analyzed together (p = 0.093), but this heterogeneity was reduced when the studies were analyzed separately as single institution versus multiinstitutional (p > 0.10 for both groups). Seven studies showed the AIS to be statistically protective against infection with an ARR and RRR ranging from 1.7% to 14.2% and 34% to 84%, respectively. The number of shunt operations requiring an AIS to prevent 1 shunt infection ranged from 7 to 59. Assuming 200 shunt cases per year, the annual savings for converting from SSs to AISs ranged from $90,000 to over $1.3 million.

CONCLUSIONS

While the authors recognized the inherent limitations in the quality and quantity of data available in the literature, this meta-analysis revealed a significant protective benefit with AIS systems, which translated into substantial hospital savings despite the added cost of an AIS. Using previously developed guidelines on treatment, the authors strongly encourage the use of AISs in all patients with hydrocephalus who require a shunt, particularly those at greatest risk for infection.

Antibiotic-impregnated ventriculoperitoneal shunts--a multi-centre British paediatric neurosurgery group (BPNG) study using historical controls

BACKGROUND

Ventriculoperitoneal shunt infection remains a significant problem. The introduction of antibiotic-impregnated shunt (AIS) systems in the prevention of shunt infection may represent a potential advance; however, there are no randomized controlled trials to establish a robust evidence-based practice. Previously published single-institution cohort studies have provided varying results on the efficacy of AIS systems in the prevention of shunt infection. In this study, we evaluate combined outcomes from three paediatric neurosurgical units in the use of AIS systems for paediatric patients with hydrocephalus.

METHODS

The three units established independent databases with data collected from varying time frames. All procedures, where a complete AIS system or part was implanted into patients from 0-16 years in age, were included. The primary outcome measure was shunt infection rate. Shunt procedures were classified as de novo (DNS) and clean revision (CRS). An infant (<1 year) de novo insertion subgroup was also analyzed. AIS shunts were compared to a historical control of non-AIS shunts and results were analysed by centre using an odds ratio with a 95% confidence interval and combined across centres by meta-analysis.

RESULTS

A total of 581 AIS implantation procedures were performed in all three units. The comparative non-AIS historical cohort comprised of 1,963 procedures. The pooled effect estimate indicated a clinical advantage for AIS shunts compared to non-AIS shunts, odds ratio (OR), 0.60 (95% CI 0.38, 0.93). The de novo infant group comprised 153 AIS systems, and 465 de novo shunts in the historical non-AIS cohort. Again the pooled effect estimate indicated a clinical advantage for AIS shunts compared to non-AIS shunts, OR 0.38 (95% CI, 0.17; 0.85); however, there was a large overlap of confidence intervals in the results from the different sites indicating the uncertainty in the treatment effect estimates. Over 80% of organisms were gram positive in the infected AIS cohort with a median time to infection of 19 days. Two rifampicin-resistant organisms and three MRSA organisms were detected.

CONCLUSION

Data from this exclusively paediatric multi-centre historical control study suggest that AIS may significantly reduce infection rates in de novo and clean revision shunt implants. Although the possibility of bias cannot be excluded due to study design, this is the largest study on an exclusively paediatric cohort comparing standard shunts to AIS implants. Future double-blinded RCTs are needed to confirm AIS efficacy.

A Multicenter Multinational Registry for Assessing Ventriculoperitoneal Shunt Infections for Hydrocephalus

BACKGROUND:

Reported infection rates after ventriculoperitoneal shunt surgery vary from 1 to 25%. Antibiotic-impregnated (AI) catheters may reduce shunt infection rates, but this is uncertain.

OBJECTIVE:

To establish a prospective shunt registry to evaluate short-term (3-month) infection rates associated with ventriculoperitoneal shunts and standard or AI catheters during surgical treatment of hydrocephalus.

METHODS:

A prospective, multicenter, noncontrolled, open-label registry investigated patients with de novo catheter implantation or catheter replacement of an existing ventriculoperitoneal shunt. The primary outcome was shunt infection.

RESULTS:

A total of 440 patients were entered into the registry at 10 sites: 3 in North America, 2 in Singapore, 4 in China and 1 in India. Seven patients were excluded. Of the 433 remaining patients, 314 had new shunts and 119 were revisions. Shunt infections occurred in 14 of 433 patients (3.2%) overall and in 2 of 37 infants (5.2%) younger than 1 year. AI catheters were used in 46 of 433 patients at 7 centers. The shunt infection rate was 0 of 46 for shunts with AI catheters and 14 of 387 (3.6%) without AI catheters. Infection rates were similar with AI catheters, adjusting for age and catheter type.

CONCLUSION:

The overall shunt infection rate was lower than in previous multicentered studies. The low infection rate and low rate of AI catheter use precludes any meaningful statement regarding the value of AI catheters in reducing the infection rate. Consideration should be given to performing a well designed, adequately powered, prospective randomized controlled trial to determine whether AI catheters reduce shunt infection rates.

Effects of antibiotic-impregnated external ventricular drains on bacterial culture results: an in vitro analysis

OBJECT

Treatment of ventriculoperitoneal shunt infections frequently requires placement of an external ventricular drain (EVD). Surveillance specimens obtained from antibiotic-impregnated (AI) EVDs may be less likely to demonstrate bacterial growth, potentially resulting in undertreatment of an infection. The purpose of this study was to assess whether AI EVDs had any significant effect on bacterial culture results compared with nonantibiotic-impregnated (NAI) EVDs.

METHODS

In vitro assays were performed using AI EVDs containing minocycline and rifampin (VentriClear II, Medtronic) and NAI EVD controls (Bioglide, Medtronic). The presence of antibiotics was evaluated via capillary electrophoresis of sterile saline drawn from AI and NAI EVDs after predefined incubation intervals. Antimicrobial activity was assessed by evaluating zones of inhibition created by the catheter aspirates on plates inoculated with a quality control strain of Staphylococcus epidermidis (American Type Culture Collection strain 12228). To determine the effects of cultures drawn through AI compared with NAI EVDs, the quality control strain was then incubated within 4 new AI and 4 new NAI EVDs for predefined intervals before being plated on culture media. Spread and streak plate culture results from each type of catheter were compared at each time interval.

RESULTS

Capillary electrophoresis showed that more minocycline than rifampin was eluted from the AI EVDs. Sterile saline samples incubated within the AI EVDs demonstrated zones of growth inhibition when placed on plates of S. epidermidis at all time intervals tested. No zones of inhibition were noted on NAI EVD control plates. When a standardized inoculum of S. epidermidis was drawn through AI and NAI EVDs, antimicrobial effects were observed after incubation in the AI EVD group only. Colony counting demonstrated that significantly fewer colonies resulted from samples drawn through AI compared with NAI EVDs at the multiple time intervals. Similarly, streak plating yielded a statistically significant number of false-negative results from AI compared with NAI EVDs at 2 time intervals.

CONCLUSIONS

The findings in the current study indicate that the risk of a false-negative culture result may be increased when a CSF sample is drawn through an AI catheter. In the management of a known shunt infection, a false-negative result from an EVD culture specimen may lead to an inappropriately short duration of antibiotic therapy. These data have significant clinical implications, particularly given the widespread use of AI drains and the current high rates of shunt reinfection after EVD use worldwide.

Antibiotic impregnated external ventricular drainage and third ventriculostomy in the management of hydrocephalus associated with posterior cranial fossa tumours

BACKGROUND

The effectiveness of antibiotic pre-treated ventricular catheters in reducing the risk of CSF infections (determined on CSF cultures) resulting from the use of per-operative external ventricular drainages (EVD) and the success rate of post-operative endoscopic third ventriculostomy (ETV) in the management of persistent hydrocephalus after posterior cranial fossa tumour removal are assessed.

METHOD

Forty-seven children (group I) were prospectively managed by means of per-operative antibiotic impregnated EVD, post-operative ICP monitoring, and ETV. The results of this group were compared with those of a control group composed by 44 children treated with the same protocol as above except for the use of not-impregnated catheters (group II).

FINDINGS

The rate of positive CSF cultures due to EVD resulted significantly lower in group I (2.1% vs 31.8%); there was no clinical evidence of CSF infections. The success rate of ETV was the same in both groups (75%). Failures of ETV occurred in the patients with subarachnoid tumour seeding and/or tumour extension to the basal cisterns. All the children of group II with failed ETV also showed a bacterial growth in the CSF.

CONCLUSIONS

Antibiotic pre-treated catheters in our experience considerably limited EVD-related bacterial growth in the CSF. Preoperative hydrocephalus resolved in 60% of the cases after tumour removal, thus confirming recent data from the literature against the routine use of preoperative ETV. In our experience postoperative ETV had a high success rate; poor results were obtained in children with tumour seeding and/or the evidence of positive CSF cultures.

Antimicrobial suture wound closure for cerebrospinal fluid shunt surgery: a prospective, double-blinded, randomized controlled trial

OBJECT

Implantation of cerebrospinal fluid (CSF) shunting devices is associated with a 5-15% risk of infection as cited in contemporary pediatric neurosurgical literature. Shunt infections typically require complete removal of the device and prolonged antibiotic treatment followed by shunt replacement. Moreover, shunt infections are commonly associated with prolonged hospital stays, potential comorbidity, and the increased risk of neurological compromise due to ventriculitis or surgical complications. The authors prospectively evaluated the incidence of CSF shunt infection following shunt procedures performed using either antimicrobial suture (AMS) or conventional suture.

METHODS

In a single-center, prospective, double-blinded, randomized controlled trial, the authors enrolled 61 patients, among whom 84 CSF shunt procedures were performed over 21 months. Randomization to the study (AMS) or control (placebo) group was stratified to minimize the effect of known shunt infection risk factors on the findings. Antibacterial shunt components were not used. The primary outcome measure was the incidence of shunt infection within 6 months of surgery.

RESULTS

The shunt infection rate in the study group was 2 (4.3%) of 46 procedures and 8 (21%) of 38 procedures in the control group (p = 0.038). There were no statistically significant differences in shunt infection risk factors between the groups (procedure type and time, age < 6 months, weight < 4 kg, recent history of shunt infection). No suture-related adverse events were reported in either group.

CONCLUSIONS

These results support the suggestion that the use of AMS for CSF shunt surgery wound closure is safe, effective, and may be associated with a reduced risk of postoperative shunt infection. A larger randomized controlled trial is needed to confirm this association.

Clinical and economic consequences of antibiotic-impregnated cerebrospinal fluid shunt catheters

OBJECT

The authors evaluated the safety and efficacy of antibiotic-impregnated shunt catheters (AISCs) and determined the cost-benefit ratio related to the fact that AISCs increase the implant costs of a shunt procedure by approximately $400 per patient.

METHODS

The control group comprised 98 adults with chronic hydrocephalus and 22 children, who were treated without AISCs (non-AISCs). In the treatment group, AISCs (Bactiseal, Codman, Johnson & Johnson) were implanted in 171 adults and 26 children. The minimum follow-up period was 6 months.

RESULTS

Important risk factors for shunt infections (such as age, comorbidity, cause of hydrocephalus, operating time, and duration of external cerebrospinal fluid drainage prior to shunt placement) did not differ between the study and control groups. In the pediatric AISC group, the frequency of premature, shunt-treated infants and the incidence of external ventricular drainage prior to shunt insertion were actually higher than those in the non-AISC group. When using AISCs, the shunt infection rate dropped from 4 to 0.6% and from 13.6 to 3.8% in the adult and the pediatric cohort, respectively. Overall the infection rate decreased from 5.8 to 1%, which was statistically significant (p = 0.0145). The average costs of a single shunt infection were $17,300 and $13,000 in children and adults, respectively. The cost-benefit calculation assumed to have saved shunt infection-related costs of approximately $50,000 in 197 AISC-treated patients due to the reduction in shunt infection rate in this group compared with costs in the control group. Despite the incremental implant costs associated with the use of AISCs, the overall reduction in infection-related costs made the use of AISCs cost beneficial in the authors' department.

CONCLUSIONS

From clinical and economic perspectives, AISCs are seemingly a valuable addition in hydrocephalus therapy.

The impact of antibiotic-impregnated catheters on shunt infection in children and neonates

INTRODUCTION

Infection remains a significant problem with cerebrospinal fluid (CSF) diversion procedures. Antibiotic-impregnated shunt catheters (AIS) have been introduced to prevent infection, mainly in the early post-operative period when most infections occur. We evaluate the impact on infection rates in children following the introduction of catheters impregnated with rifampicin and clindamycin.

MATERIALS AND METHODS

The study was a retrospective analysis of all paediatric shunt procedures undertaken after the introduction of AIS systems in 2003. All procedures where a complete AIS system was implanted were included. For the purpose of analysis, shunt procedures were classified as de novo (group 1), clean revision (group 2) and following external ventricular drainage with either sterile CSF (group 3) or infected CSF (group 4). Results were compared to a historical cohort of shunt procedures undertaken before the introduction of AIS catheters.

RESULTS

A total of 214 AIS were implanted in 150 children between October 2003 and December 2006. There were 4 infections in group 1 (8.5%), 6 infections in group 2 (5.3%) and 11 infections in groups 3 and 4 (20%). The historical control group comprised 77 shunts in 65 children. The infection rate in neonatal de novo shunts reduced from 27 to 10.4% following the introduction of AIS catheters.

CONCLUSIONS

AIS catheters can reduce the number of shunt infections seen in clinical practice in certain subgroups. This has had a significant impact on the neonatal hydrocephalic population. The high risk of shunt infection after a period of external ventricular drainage raises the issue of emergence of bacterial resistance.

Sterile surgical technique for shunt placement reduces the shunt infection rate in children: preliminary analysis of a prospective protocol in 115 consecutive procedures

OBJECTIVE

The objective of this study was to evaluate whether the rigid application of a sterile protocol for shunt placement was applicable on a routine basis and allowed the reduction of shunt infections (SI) in children.

MATERIALS AND METHODS

Since 2001, a rigid sterile protocol for shunt placement in children using neither antibiotic-impregnated catheters nor laminar airflow was prospectively applied at Erasme Hospital, Brussels, Belgium. For assessing the protocol efficacy before continuation, we preliminarily analyzed the results of the first 100 operated children (43 females, 57 males, 49 aged <12 months; 115 consecutive shunt placement/revision procedures). All procedures were performed by the same senior surgeon, one assistant, one circulating nurse, one anesthesiologist. The sterile protocol was rigidly imposed to these four staff members: uniformed surgical technique; limited implant and skin edge manipulation; minimized human circulation in the room; scheduling surgery as first morning operation; avoiding postoperative cerebrospinal fluid (CSF) leak; double gloving; procedures of less than 30-min duration; systemic antibiotics prophylaxis. We analyzed separately: (1) children carrying an increased risk of SI (n = 38) due to preoperative external ventricular drainage, CSF leak, meningitis, glucocorticoids, chemotherapy; (2) children aged <12 months; (3) procedures for shunt revision.

RESULTS

Errors in protocol application were recorded in 71/115 procedures. They were mainly done by non-surgical staff, decreased with time and were medically justified in some young children. Surprisingly, no SI occurred (follow-up, 4 to 70 months). One child developed an appendicitis with peritonitis (Streptococcus faecalis) after 6 months. No SI was found. After peritonitis was cured, shunt reinsertion was uneventful.

CONCLUSION

These preliminary results suggest that a uniform and drastic sterile surgical technique for shunt placement: (1) can be rigidly applied on a routine basis; (2) can lower the early SI rate below 1%; (3) might have a stronger impact to reduce SI than using antibiotic-impregnated catheters and optimizing the operative environment such as using laminar airflow and reducing the non-surgical staff. This last issue will be evaluated further in the present ongoing protocol.

Reduction in shunt infection using antibiotic impregnated CSF shunt catheters: An Australian prospective study

Antibiotic impregnated shunt catheters have emerged as a promising tool against the continuing challenge of shunt infection. We present our prospective evaluation of the efficacy of antibiotic (rifampicin and clindamycin) impregnated cerebrospinal fluid (CSF) shunt catheters (AIC) in a mixed paediatric and adult Australian population. We have prospectively evaluated all the cerebrospinal fluid shunt procedures carried out in our institution over a 3-year period since July 2002, after the introduction of AIC in our practice. Patient demographics, indication for shunt procedure, risk factors for infection, shunt infections and other relevant factors were documented. The data has been compared with similar data collected over the previous 7 years of our experience with non-antibiotic impregnated catheters for CSF shunt procedures. Pearson's chi-square and Fisher's exact tests are used for statistical evaluation. From July 2002 to June 2005, 243 shunt procedures were carried out using AICs in 178 patients. There were three shunt infections (1.2%). Rigorous retrospective evaluation of shunt procedures over the preceding 7 years revealed 36 infections in 551 shunt procedures (6.5%). This reduction in the infection rate was statistically significant (p=0.0015 on Pearson's chi-square test and p=0.000529 on Fisher's exact test). We also report that the introduction of ceftriaxone prophylaxis during this period was associated with a reduction in Gram-negative shunt infection, but no effect on overall infection rate. We report rifampicin and clindamycin impregnated CSF shunt catheters significantly reduce the rate of shunt infection in Australian clinical practice. This data and the literature support the routine usage of AIC for all CSF shunt procedures.

Do antibiotic-impregnated shunts in hydrocephalus therapy reduce the risk of infection? An observational study in 258 patients

BACKGROUND

Shunt infection in hydrocephalus patients is a severe, even life-threatening complication. Antibiotic-impregnated shunts (AIS) have been developed in an attempt to reduce rate of shunt infection. The study was performed to analyze if AIS can diminish the rate of shunt infection. The pathogenic nature of shunt infection in patients with AIS systems and those without antibiotic impregnated shunts (non-AIS) was compared.

METHODS

Over a period of 24 months in the Department of Neurosurgery at University Hospital of Tübingen shunt surgery was performed in 258 patients. In 86 patients AIS systems were implanted. Shunt catheters were commercially impregnated with clindamycin and rifampicin. Analysis of the clinical data included sex, age, classification of hydrocephalus, shunt types and risk factors for shunt infection [age (< 1 year and > 80 years), prematurely born patients, external ventricular drainage, former shunt infection, former systemic infection, disturbance of consciousness, former radiation-/chemotherapy]. Infection rates and underlying bacterial pathogens of patients with AIS were compared to patients with implanted non-AIS systems (172 patients).

RESULTS

AIS and non-AIS patients did not differ in sex, etiology of hydrocephalus and the shunt type. In the AIS group 72 out of 86 patients had at least one risk factor (83.7 %), compared to 126 patients in the non-AIS group (73.3 %). There was no significant difference between the two groups (p = 0.0629; Fisher's exact test). In patients with no risk factors, only one patient with non-AIS suffered from shunt infection. In patients with one or more risk factors the rate for shunt infection was 7.14 % in patients with non-AIS and 6.94 % in patients with AIS. Former shunt infection (p = 0.0124) was related to higher risk for shunt infection. The use of AIS had therefore no significant advantage (p = 0.8611; multiple logistic regression). Significantly related to a shunt infection was the number of shunt surgeries. 190 interventions in the AIS group (2.21 interventions per patient) and 408 in the non-AIS group (2.37 interventions per patient) had been performed (p = 0.3063; Wilcoxon). There was no shunt infection in the group of patients on whom only one shunt surgery was performed. In patients with at least two shunt surgeries the infection rate was 9%. The infection rate in AIS patients was 5/52 (9.6 %) and in the non-AIS 10/114 (8.77 %), (p = 1.0; Fisher's exact test). Staphylococcus epidermidis was the most frequent pathogen for shunt infection. Fourteen out of 15 infections occurred within the first 6 months of surgery. The most frequent pathogen for shunt infection was S. epidermidis. No toxic or allergic complications were seen using the AIS shunt systems. The presented data show a remarkably low infection rate of 5.8 % in the non-AIS group compared to other studies which demonstrated a significant decrease in the infection rate by AIS.

CONCLUSION

AIS did not significantly reduce shunt infection in hydrocephalus patients in the presented study. In the AIS group three patients suffered from shunt infections caused by skin ulceration or neurosurgical procedures with exposure of the cerebrospinal liquor after shunt implantation. AIS was not developed to prevent infection in such cases, therefore an advantage of AIS can not be excluded. In view of the presented data and the small number of reported studies a prospective randomized multicenter study is required.