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John R. W. Kestle, Abhaya V. Kulkarni and Benjamin C. Warf

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Shobhan Vachhrajani, Abhaya V. Kulkarni and John R. W. Kestle

In the era of evidence-based medicine, clinical practice guidelines (CPGs) have become an integral part of many aspects of medical practice. Because practicing neurosurgeons rarely have the time or, in some cases, the methodological expertise, to assess and assimilate the totality of primary research, CPGs can in theory provide a vehicle through which neurosurgeons could more efficiently integrate the most current evidence into patient management. Clinical practice guidelines have been met with some skepticism, however, particularly within the neurosurgical community. Some have expressed concerns that the promise of CPGs has not been matched by the reality. Others who oppose CPGs fear that they hinder the art of medicine, and limit physician and patient autonomy. The purpose of this paper is to provide the practicing neurosurgeon with an up-to-date review of CPGs. The authors discuss some of the complexities and recent advancements in CPG development, appraisal, and publication. An overview of the various systems for grading medical evidence and issuing CPG recommendations, each of which has its advantages and disadvantages, is included, and the current knowledge on the impact of CPGs in 2 important realms, patient care and medicolegal issues, is discussed.

The purpose of this review is to provide a balanced, current synopsis of what CPGs are, how they are developed, and what they can and cannot do. The authors hope that this will allow neurosurgeons to make more informed decisions about the many CPGs that will inevitably become an essential component of medical practice in the years to come.

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Mark N. Hadley

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Editorial

Prediction, with restriction

Alan R. Cohen

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Abhaya V. Kulkarni, James M. Drake, John R. W. Kestle, Conor L. Mallucci, Spyros Sgouros and Shlomi Constantini

Object

The authors recently developed and internally validated the ETV Success Score (ETVSS)—a simplified means of predicting the 6-month success rate of endoscopic third ventriculostomy (ETV) for a child with hydrocephalus, based on age, etiology of hydrocephalus, and presence of a previous shunt. A high ETVSS predicts a high chance of early ETV success. In this paper, they assess the clinical utility of the ETVSS by determining whether long-term survival outcomes for ETV versus shunt insertion are different within strata of ETVSS (low, moderate, and high scores).

Methods

A multicenter, international cohort of children (≤ 19 years old) with newly diagnosed hydrocephalus treated with either ETV (489 patients) or shunt insertion (720 patients) was analyzed. The ETVSS was calculated for all patients. Survival analyses with time-dependent modeling of the hazard ratios were performed.

Results

For the High-ETVSS Group (255 ETV-treated patients, 117 shunt-treated patients), ETV appeared to have a lower risk of failure right from the early postoperative phase and became more favorable with time. For the Moderate-ETVSS Group (172 ETV-treated patients, 245 shunt-treated patients), ETV appeared to have a higher initial failure rate, but after about 3 months the instantaneous risk of ETV failure became slightly lower than shunt failure (that is, the hazard ratio became < 1). For the Low-ETVSS Group (62 ETV-treated patients, 358 shunt-treated patients), the early risk of ETV failure was much higher than the risk of shunt failure, but the instantaneous risk of ETV failure became lower than the risk of shunt failure at about 6 months following surgery (the hazard ratio became < 1).

Conclusions

Across all ETVSS strata, the risk of ETV failure becomes progressively lower compared with the risk of shunt failure with increasing time from the surgery. In the best ETV candidates (ETVSS ≥ 80), however, the risk of ETV failure is lower than the risk of shunt failure very soon after surgery, while for less-than-ideal ETV candidates (ETVSS ≤ 70), the risk of ETV failure is initially higher than the risk of shunt failure and only becomes lower after 3–6 months from surgery. These results need to be confirmed by larger, prospective, and preferably randomized studies.

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John R. W. Kestle, Hugh J. L. Garton, William E. Whitehead, James M. Drake, Abhaya V. Kulkarni, D. Douglas Cochrane, Cheryl Muszynski and Marion L. Walker

Object

Approximately 10% of cerebrospinal fluid (CSF) shunt operations are associated with infection and require removal or externalization of the shunt, in-hospital treatment with antibiotic agents, and insertion of a new shunt. In a previous survey, the authors identified substantial variation in the duration of antibiotic therapy as well as the duration of hospital stay. The present multicenter pilot study was undertaken to evaluate current strategies in the treatment of shunt infection.

Methods

Patients were enrolled in the study if they had a successful treatment of a CSF shunt infection proved by culture of a CSF specimen. Details of their care and the incidence of culture-proved reinfection were recorded.

Seventy patients from 10 centers were followed up for 1 year after their CSF shunt infection. The initial management of the infection was shunt externalization in 17 patients, shunt removal and external ventricular drain insertion in 50, and antibiotic treatment alone in three. Reinfection occurred in 18 patients (26%). Twelve of the 18 reinfections were caused by the same organism and six were due to new organisms. The treatment time varied from 4 to 47 days, with a mean of 17.4 days for those who later experienced a reinfection compared with 16.2 days for those who did not. The most common organism (Staphylococcus epidermidis, 34 patients) was associated with a reinfection rate of 29% and a mean treatment time of 12.8 days for those who suffered reinfection and 12.5 days for those who did not.

Conclusions

Reinfection after treatment of a CSF shunt infection is alarmingly common. According to the data available, the incidence of reinfection does not appear to be related to the duration of antibiotic therapy.

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Jay Riva-Cambrin, Chevis N. Shannon, Richard Holubkov, William E. Whitehead, Abhaya V. Kulkarni, James Drake, Tamara D. Simon, Samuel R. Browd, John R. W. Kestle and John C. Wellons III

Object

There is little consensus regarding the indications for surgical CSF diversion (either with implanted temporizing devices [reservoir or subgaleal shunt] or shunt alone) in preterm infants with posthemorrhagic hydrocephalus. The authors determined clinical and neuroimaging factors associated with the use of surgical CSF diversion among neonates with intraventricular hemorrhage (IVH), and describe variations in practice patterns across 4 large pediatric centers.

Methods

The use of implanted temporizing devices and conversion to permanent shunts was examined in a consecutive sample of 110 neonates surgically treated for IVH related to prematurity from the 4 clinical centers of the Hydrocephalus Clinical Research Network (HCRN). Clinical, neuroimaging, and so-called processes of care factors were analyzed.

Results

Seventy-three (66%) of the patients underwent temporization procedures, including 50 ventricular reservoir and 23 subgaleal shunt placements. Center (p < 0.001), increasing ventricular size (p = 0.04), and bradycardia (p = 0.07) were associated with the use of an implanted temporizing device, whereas apnea, occipitofrontal circumference (OFC), and fontanel assessments were not. Implanted temporizing devices were converted to permanent shunts in 65 (89%) of the 73 neonates. Only a full fontanel (p < 0.001) and increased ventricular size (p = 0.002) were associated with conversion of the temporizing devices to permanent shunts, whereas center, OFCs, and clot characteristics were not.

Conclusions

Considerable center variability exists in neurosurgical approaches to temporization of IVH in prematurity within the HCRN; however, variation between centers is not seen with permanent shunting. Increasing ventricular size—rather than classic clinical findings such as increasing OFCs—represents the threshold for either temporization or shunting of CSF.

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John R. W. Kestle, Jay Riva-Cambrin, John C. Wellons III, Abhaya V. Kulkarni, William E. Whitehead, Marion L. Walker, W. Jerry Oakes, James M. Drake, Thomas G. Luerssen, Tamara D. Simon and Richard Holubkov

Object

Quality improvement techniques are being implemented in many areas of medicine. In an effort to reduce the ventriculoperitoneal shunt infection rate, a standardized protocol was developed and implemented at 4 centers of the Hydrocephalus Clinical Research Network (HCRN).

Methods

The protocol was developed sequentially by HCRN members using the current literature and prior institutional experience until consensus was obtained. The protocol was prospectively applied at each HCRN center to all children undergoing a shunt insertion or revision procedure. Infections were defined on the basis of CSF, wound, or pseudocyst cultures; wound breakdown; abdominal pseudocyst; or positive blood cultures in the presence of a ventriculoatrial shunt. Procedures and infections were measured before and after protocol implementation.

Results

Twenty-one surgeons at 4 centers performed 1571 procedures between June 1, 2007, and February 28, 2009. The minimum follow-up was 6 months. The Network infection rate decreased from 8.8% prior to the protocol to 5.7% while using the protocol (p = 0.0028, absolute risk reduction 3.15%, relative risk reduction 36%). Three of 4 centers lowered their infection rate. Shunt surgery after external ventricular drainage (with or without prior infection) had the highest infection rate. Overall protocol compliance was 74.5% and improved over the course of the observation period. Based on logistic regression analysis, the use of BioGlide catheters (odds ratio [OR] 1.91, 95% CI 1.19–3.05; p = 0.007) and the use of antiseptic cream by any members of the surgical team (instead of a formal surgical scrub by all members of the surgical team; OR 4.53, 95% CI 1.43–14.41; p = 0.01) were associated with an increased risk of infection.

Conclusions

The standardized protocol for shunt surgery significantly reduced shunt infection across the HCRN. Overall protocol compliance was good. The protocol has established a common baseline within the Network, which will facilitate assessment of new treatments. Identification of factors associated with infection will allow further protocol refinement in the future.

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William E. Whitehead, Jay Riva-Cambrin, John C. Wellons III, Abhaya V. Kulkarni, Richard Holubkov, Anna Illner, W. Jerry Oakes, Thomas G. Luerssen, Marion L. Walker, James M. Drake and John R. W. Kestle

Object

Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are associated with prolonged shunt survival. Developing surgical techniques for accurate catheter insertion could, therefore, be beneficial to patients. This study was conducted to determine if the rate of accurate catheter location with intraoperative ultrasound guidance could exceed 80%.

Methods

The authors conducted a prospective, multicenter study of children (< 18 years) requiring first-time treatment for hydrocephalus with a ventriculoperitoneal shunt. Using intraoperative ultrasound, surgeons were required to target the frontal horn or trigone for catheter tip placement. An intraoperative ultrasound image was obtained at the time of catheter insertion. Ventricular catheter location, the primary outcome measure, was determined from the first postoperative image. A control group of patients treated by nonultrasound surgeons (conventional surgeons) were enrolled using the same study criteria. Conventional shunt surgeons also agreed to target the frontal horn or trigone for all catheter insertions. Patients were triaged to participating surgeons based on call schedules at each center. A pediatric neuroradiologist blinded to method of insertion, center, and surgeon determined ventricular catheter tip location.

Results

Eleven surgeons enrolled as ultrasound surgeons and 6 as conventional surgeons. Between February 2009 and February 2010, 121 patients were enrolled at 4 Hydrocephalus Clinical Research Network centers. Experienced ultrasound surgeons (> 15 cases prior to study) operated on 67 patients; conventional surgeons operated on 52 patients. Experienced ultrasound surgeons achieved accurate catheter location in 39 (59%) of 66 patients, 95% CI (46%–71%). Intraoperative ultrasound images were compared with postoperative scans. In 32.7% of cases, the catheter tip moved from an accurate location on the intraoperative ultrasound image to an inaccurate location on the postoperative study. This was the most significant factor affecting accuracy. In comparison, conventional surgeons achieved accurate location in 24 (49.0%) of 49 cases (95% CI [34%–64%]). The shunt survival rate at 1 year was 70.8% in the experienced ultrasound group and 66.9% in the conventional group (p = 0.66). Ultrasound surgeons had more catheters surrounded by CSF (30.8% vs 6.1%, p = 0.0012) and away from the choroid plexus (72.3% vs 58.3%, p = 0.12), and fewer catheters in the brain (3% vs 22.4%, p = 0.0011) and crossing the midline (4.5% vs 34.7%, p < 0.001), but they had a higher proportion of postoperative pseudomeningocele (10.1% vs 3.8%, p = 0.30), wound dehiscence (5.8% vs 0%, p = 0.13), CSF leak (10.1% vs 1.9%, p = 0.14), and shunt infection (11.6% vs 5.8%, p = 0.35).

Conclusions

Ultrasound-guided shunt insertion as performed in this study was unable to consistently place catheters into the frontal horn or trigone. The technique is safe and achieves outcomes similar to other conventional shunt insertion techniques. Further efforts to improve accurate catheter location should focus on prevention of catheter migration that occurs between intraoperative placement and postoperative imaging. Clinical trial registration no.: NCT01007786 (ClinicalTrials.gov).

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Abhaya V. Kulkarni, Jay Riva-Cambrin, Samuel R. Browd, James M. Drake, Richard Holubkov, John R. W. Kestle, David D. Limbrick, Curtis J. Rozzelle, Tamara D. Simon, Mandeep S. Tamber, John C. Wellons III and William E. Whitehead

Object

The use of endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) has been advocated as an alternative to CSF shunting in infants with hydrocephalus. There are limited reports of this procedure in the North American population, however. The authors provide a retrospective review of the experience with combined ETV + CPC within the North American Hydrocephalus Clinical Research Network (HCRN).

Methods

All children (< 2 years old) who underwent an ETV + CPC at one of 7 HCRN centers before November 2012 were included. Data were collected retrospectively through review of hospital records and the HCRN registry. Comparisons were made to a contemporaneous cohort of 758 children who received their first shunt at < 2 years of age within the HCRN.

Results

Thirty-six patients with ETV + CPC were included (13 with previous shunt). The etiologies of hydrocephalus were as follows: intraventricular hemorrhage of prematurity (9 patients), aqueductal stenosis (8), myelomeningocele (4), and other (15). There were no major intraoperative or early postoperative complications. There were 2 postoperative CSF infections. There were 2 deaths unrelated to hydrocephalus and 1 death from seizure. In 18 patients ETV + CPC failed at a median time of 30 days after surgery (range 4–484 days). The actuarial 3-, 6-, and 12-month success for ETV + CPC was 58%, 52%, and 52%. Time to treatment failure was slightly worse for the 36 patients with ETV + CPC compared with the 758 infants treated with shunts (p = 0.012). Near-complete CPC (≥ 90%) was achieved in 11 cases (31%) overall, but in 50% (10 of 20 cases) in 2012 versus 6% (1 of 16 cases) before 2012 (p = 0.009). Failure was higher in children with < 90% CPC (HR 4.39, 95% CI 0.999–19.2, p = 0.0501).

Conclusions

The early North American multicenter experience with ETV + CPC in infants demonstrates that the procedure has reasonable safety in selected cases. The degree of CPC achieved might be associated with a surgeon's learning curve and appears to affect success, suggesting that surgeon training might improve results.