Tamara D. Simon, Matthew P. Kronman, Kathryn B. Whitlock, Nancy E. Gove, Nicole Mayer-Hamblett, Samuel R. Browd, D. Douglas Cochrane, Richard Holubkov, Abhaya V. Kulkarni, Marcie Langley, David D. Limbrick Jr., Thomas G. Luerssen, W. Jerry Oakes, Jay Riva-Cambrin, Curtis Rozzelle, Chevis Shannon, Mandeep Tamber, John C. Wellons III, William E. Whitehead and John R. W. Kestle
CSF shunt infection requires both surgical and antibiotic treatment. Surgical treatment includes either total shunt removal with external ventricular drain (EVD) placement followed by new shunt insertion, or distal shunt externalization followed by new shunt insertion once the CSF is sterile. Antibiotic treatment includes the administration of intravenous antibiotics. The Hydrocephalus Clinical Research Network (HCRN) registry provides a unique opportunity to understand reinfection following treatment for CSF shunt infection. This study examines the association of surgical and antibiotic decisions in the treatment of first CSF shunt infection with reinfection.
A prospective cohort study of children undergoing treatment for first CSF infection at 7 HCRN hospitals from April 2008 to December 2012 was performed. The HCRN consensus definition was used to define CSF shunt infection and reinfection. The key surgical predictor variable was surgical approach to treatment for CSF shunt infection, and the key antibiotic treatment predictor variable was intravenous antibiotic selection and duration. Cox proportional hazards models were constructed to address the time-varying nature of the characteristics associated with shunt surgeries.
Of 233 children in the HCRN registry with an initial CSF shunt infection during the study period, 38 patients (16%) developed reinfection over a median time of 44 days (interquartile range [IQR] 19–437). The majority of initial CSF shunt infections were treated with total shunt removal and EVD placement (175 patients; 75%). The median time between infection surgeries was 15 days (IQR 10–22). For the subset of 172 infections diagnosed by CSF culture, the mean ± SD duration of antibiotic treatment was 18.7 ± 12.8 days. In all Cox proportional hazards models, neither surgical approach to infection treatment nor overall intravenous antibiotic duration was independently associated with reinfection. The only treatment decision independently associated with decreased infection risk was the use of rifampin. While this finding did not achieve statistical significance, in all 5 Cox proportional hazards models both surgical approach (other than total shunt removal at initial CSF shunt infection) and nonventriculoperitoneal shunt location were consistently associated with a higher hazard of reinfection, while the use of ultrasound was consistently associated with a lower hazard of reinfection.
Neither surgical approach to treatment nor antibiotic duration was associated with reinfection risk. While these findings did not achieve statistical significance, surgical approach other than total removal at initial CSF shunt infection was consistently associated with a higher hazard of reinfection in this study and suggests the feasibility of controlling and standardizing the surgical approach (shunt removal with EVD placement). Considerably more variation and equipoise exists in the duration and selection of intravenous antibiotic treatment. Further consideration should be given to the use of rifampin in the treatment of CSF shunt infection. High-quality studies of the optimal duration of antibiotic treatment are critical to the creation of evidence-based guidelines for CSF shunt infection treatment.
John C. Wellons III, Chevis N. Shannon, Richard Holubkov, Jay Riva-Cambrin, Abhaya V. Kulkarni, David D. Limbrick Jr., William Whitehead, Samuel Browd, Curtis Rozzelle, Tamara D. Simon, Mandeep S. Tamber, W. Jerry Oakes, James Drake, Thomas G. Luerssen, John Kestle and For the Hydrocephalus Clinical Research Network
Previous Hydrocephalus Clinical Research Network (HCRN) retrospective studies have shown a 15% difference in rates of conversion to permanent shunts with the use of ventriculosubgaleal shunts (VSGSs) versus ventricular reservoirs (VRs) as temporization procedures in the treatment of hydrocephalus due to high-grade intraventricular hemorrhage (IVH) of prematurity. Further research in the same study line revealed a strong influence of center-specific decision-making on shunt outcomes. The primary goal of this prospective study was to standardize decision-making across centers to determine true procedural superiority, if any, of VSGS versus VR as a temporization procedure in high-grade IVH of prematurity.
The HCRN conducted a prospective cohort study across 6 centers with an approximate 1.5- to 3-year accrual period (depending on center) followed by 6 months of follow-up. Infants with premature birth, who weighed less than 1500 g, had Grade 3 or 4 IVH of prematurity, and had more than 72 hours of life expectancy were included in the study. Based on a priori consensus, decisions were standardized regarding the timing of initial surgical treatment, upfront shunt versus temporization procedure (VR or VSGS), and when to convert a VR or VSGS to a permanent shunt. Physical examination assessment and surgical technique were also standardized. The primary outcome was the proportion of infants who underwent conversion to a permanent shunt. The major secondary outcomes of interest included infection and other complication rates.
One hundred forty-five premature infants were enrolled and met criteria for analysis. Using the standardized decision rubrics, 28 infants never reached the threshold for treatment, 11 initially received permanent shunts, 4 were initially treated with endoscopic third ventriculostomy (ETV), and 102 underwent a temporization procedure (36 with VSGSs and 66 with VRs). The 2 temporization cohorts were similar in terms of sex, race, IVH grade, head (orbitofrontal) circumference, and ventricular size at temporization. There were statistically significant differences noted between groups in gestational age, birth weight, and bilaterality of clot burden that were controlled for in post hoc analysis. By Kaplan-Meier analysis, the 180-day rates of conversion to permanent shunts were 63.5% for VSGS and 74.0% for VR (p = 0.36, log-rank test). The infection rate for VSGS was 14% (5/36) and for VR was 17% (11/66; p = 0.71). The overall compliance rate with the standardized decision rubrics was noted to be 90% for all surgeons.
A standardized protocol was instituted across all centers of the HCRN. Compliance was high. Choice of temporization techniques in premature infants with IVH does not appear to influence rates of conversion to permanent ventricular CSF diversion. Once management decisions and surgical techniques are standardized across HCRN sites, thus minimizing center effect, the observed difference in conversion rates between VSGSs and VRs is mitigated.
John R. W. Kestle, Richard Holubkov, D. Douglas Cochrane, Abhaya V. Kulkarni, David D. Limbrick Jr., Thomas G. Luerssen, W. Jerry Oakes, Jay Riva-Cambrin, Curtis Rozzelle, Tamara D. Simon, Marion L. Walker, John C. Wellons III, Samuel R. Browd, James M. Drake, Chevis N. Shannon, Mandeep S. Tamber, William E. Whitehead and The Hydrocephalus Clinical Research Network
In a previous report by the same research group (Kestle et al., 2011), compliance with an 11-step protocol was shown to reduce CSF shunt infection at Hydrocephalus Clinical Research Network (HCRN) centers (from 8.7% to 5.7%). Antibiotic-impregnated catheters (AICs) were not part of the protocol but were used off protocol by some surgeons. The authors therefore began using a new protocol that included AICs in an effort to reduce the infection rate further.
The new protocol was implemented at HCRN centers on January 1, 2012, for all shunt procedures (excluding external ventricular drains [EVDs], ventricular reservoirs, and subgaleal shunts). Procedures performed up to September 30, 2013, were included (21 months). Compliance with the protocol and outcome events up to March 30, 2014, were recorded. The definition of infection was unchanged from the authors' previous report.
A total of 1935 procedures were performed on 1670 patients at 8 HCRN centers. The overall infection rate was 6.0% (95% CI 5.1%–7.2%). Procedure-specific infection rates varied (insertion 5.0%, revision 5.4%, insertion after EVD 8.3%, and insertion after treatment of infection 12.6%). Full compliance with the protocol occurred in 77% of procedures. The infection rate was 5.0% after compliant procedures and 8.7% after noncompliant procedures (p = 0.005). The infection rate when using this new protocol (6.0%, 95% CI 5.1%–7.2%) was similar to the infection rate observed using the authors' old protocol (5.7%, 95% CI 4.6%–7.0%).
CSF shunt procedures performed in compliance with a new infection prevention protocol at HCRN centers had a lower infection rate than noncompliant procedures. Implementation of the new protocol (including AICs) was associated with a 6.0% infection rate, similar to the infection rate of 5.7% from the authors' previously reported protocol. Based on the current data, the role of AICs compared with other infection prevention measures is unclear.
William E. Whitehead, Jay Riva-Cambrin, John C. Wellons III, Abhaya V. Kulkarni, Samuel Browd, David Limbrick, Curtis Rozzelle, Mandeep S. Tamber, Tamara D. Simon, Chevis N. Shannon, Richard Holubkov, W. Jerry Oakes, Thomas G. Luerssen, Marion L. Walker, James M. Drake and John R. W. Kestle
Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone of the lateral ventricle. However, techniques for accurate catheter placement have not been developed. The authors recently reported a prospective study designed to test the accuracy of catheter placement with the assistance of intraoperative ultrasound, but the results were poor (accurate placement in 59%). A major reason for the poor accurate placement rate was catheter movement that occurred between the time of the intraoperative ultrasound image and the first postoperative scan (33% of cases). The control group of non–ultrasound using surgeons also had a low rate of accurate placement (accurate placement in 49%). The authors conducted an exploratory post hoc analysis of patients in their ultrasound study to identify factors associated with either catheter movement or poor catheter placement so that improved surgical techniques for catheter insertion could be developed.
The authors investigated the following risk factors for catheter movement and poor catheter placement: age, ventricular size, cortical mantle thickness, surgeon experience, surgeon experience with ultrasound prior to trial, shunt entry site, shunt hardware at entry site, ventricular catheter length, and use of an ultrasound probe guide for catheter insertion. Univariate analysis followed by multivariate logistic regression models were used to determine which factors were independent risk factors for either catheter movement or inaccurate catheter location.
In the univariate analyses, only age < 6 months was associated with catheter movement (p = 0.021); cortical mantle thickness < 1 cm was near-significant (p = 0.066). In a multivariate model, age remained significant after adjusting for cortical mantle thickness (OR 8.35, exact 95% CI 1.20–infinity). Univariate analyses of factors associated with inaccurate catheter placement showed that age < 6 months (p = 0.001) and a posterior shunt entry site (p = 0.021) were both associated with poor catheter placement. In a multivariate model, both age < 6 months and a posterior shunt entry site were independent risk factors for poor catheter placement (OR 4.54, 95% CI 1.80–11.42, and OR 2.59, 95% CI 1.14–5.89, respectively).
Catheter movement and inaccurate catheter placement are both more likely to occur in young patients (< 6 months). Inaccurate catheter placement is also more likely to occur in cases involving a posterior shunt entry site than those involving an anterior shunt entry site. Future clinical studies aimed at improving shunt placement techniques must consider the effects of young age and choice of entry site on catheter location.