Long-term follow-up data from the Shunt Design Trial

A standardized protocol to reduce cerebrospinal fluid shunt infection: the Hydrocephalus Clinical Research Network Quality Improvement Initiative

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.

Development of Microfabricated Magnetic Actuators for Removing Cellular Occlusion

Here we report on the development of torsional magnetic microactuators for displacing biological materials in implantable catheters. Static and dynamic behaviors of the devices were characterized in air and in fluid using optical experimental methods. The devices were capable of achieving large deflections (>60°) and had resonant frequencies that ranged from 70 Hz to 1.5 kHz in fluid. The effect of long-term actuation (>2.5 · 10(8) cycles) was quantified using resonant shift as the metric (Δf < 2%). Cell-clearing capabilities of the devices were evaluated by examining the effect of actuation on a layer of aggressively growing adherent cells. On average, actuated microdevices removed 37.4% of the adherent cell layer grown over the actuator surface. The effect of actuation time, deflection angle, and beam geometry were evaluated. The experimental results indicate that physical removal of adherent cells at the microscale is feasible using magnetic microactuation.

Shunt failure due to intracranial migration of BioGlide ventricular catheters

OBJECT

In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to the Bio-Glide Snap Shunt ventricular catheters. This prompted a retrospective review of the patient cohort and resulted in a recall by the FDA in the US.

METHODS

After the index cases were identified, the FDA was notified by the hospital, leading to a recall of the product. Hospital operative logs were used to identify patients in whom the affected products were used. A letter describing the risk was sent to all patients offering a free screening CT scan to look for disconnection. A call center was established to respond to patient questions, and an informational video was made available on the hospital website. The authors reviewed the records of the index cases and other cases subsequently identified.

RESULTS

Seven index cases and an additional 16 cases of disconnection were identified in the 466 patients in whom a BioGlide Snap Shunt ventricular catheter had been implanted. Mean time to disconnection was 2.7 years (range 4 days-5.8 years). Computed tomography slices in the plane of the catheter helped visualize disconnections. Retrieval was difficult, and in 5 patients the disconnected catheter was not removable. Three catheters were completely within the ventricle. At presentation, 4 children suffered from severe neurological deficits, including one who died as a result of the shunt malfunction.

CONCLUSIONS

BioGlide snap-design ventricular catheters are prone to disconnection. Continued vigilance and specific imaging are important. Catheter removal after disconnection may be difficult. Elective removal prior to disconnection in asymptomatic children has not been performed.

Can using a peel-away sheath in shunt implantation prevent ventricular catheter obstruction?

PURPOSE

Shunt obstruction is the most common shunt complication. In 2003, Kehler et al. used peel-away sheath while implanting the ventricular catheter in 20 patients. They found less revision rate in the peel-away sheath group. We aimed to test the efficacy of this technique in cadavers.

METHODS

We used 100 fresh brains obtained from medicolegal autopsies. Posterior parietal and frontal approaches were used to puncture the lateral ventricle in each cerebral hemisphere. The ventricle is punctured with a peel-away sheath system. After the ventricle is reached, the mandarin is retracted and the ventricular catheter is introduced through the opening. The ventricular catheter was removed from the ventricle, the opening at the tip of the ventricular catheter was checked out for obstruction, and the number of patent and plugged openings was recorded. This procedure was repeated four times for each location with and without using peel-away sheath. The control group consisted of the procedures done without using peel-away sheath.

RESULTS

The number of the plugged openings in the peel-away sheath group was significantly smaller than the control group. There was no significant difference between the two groups in terms of gender and left and right cerebral hemispheres. The obstruction rate was significantly lower in the posterior parietal approach. Pearson's correlation showed that increasing age was associated with less obstruction rate.

CONCLUSION

Peel-away sheath decreases the number of plugged openings of the ventricular catheter. A clinical cooperative study is needed to prove that a peel-away sheath should be included in the ventricular shunt systems in the market.

Modified bilateral subtemporal decompression for resistant slit ventricle syndrome

PURPOSE

Slit ventricle syndrome (SVS) remains a major problem for early shunted children. Several conservative and surgical treatment paradigms have been suggested; however, there is no consensus on the optimal surgical treatment. We present our experience using bilateral subtemporal decompressions with dura and arachnoid opening for the treatment of a subgroup of children with severe and resistant SVS.

METHODS

Fifteen children with severe and resistant SVS underwent a modified bilateral subtemporal craniectomy, with dura and arachnoid opening. Their clinical and radiological data were retrospectively reviewed.

RESULTS

Seven (46.6%) patients had a complete recovery from their symptoms with a follow-up of 5.9 ± 2.6 years.The remaining eight (53.3%), underwent additional surgeries. Four (26.6%), had a single proximal shunt revision after dilatation of their ventricles. Following these procedures these four children are well and stable with a follow-up of 1.8 ± 2 years. The other four had further cranial vault expansion, one of which was followed by a proximal shunt revision. Thus, 11 of these 15 patients (73.4%) had a very good outcome, attributable to this technique, with a mean follow-up of 4.5 ± 3 years.

CONCLUSIONS

Modified bilateral subtemporal decompression with dura and arachnoid opening yields a high cure rate for severe and resistant slit ventricle syndrome. Proximal shunt revision may be safely performed in a subset of patients that dilate their ventricles following the procedure. Further cranial expansion may be reserved for children with recurrent SVS symptoms who do not respond to STD and remain with very small ventricles.

Evaluation of the ShuntCheck Noninvasive Thermal Technique for Shunt Flow Detection in Hydrocephalic Patients

BACKGROUND:

ShuntCheck (Neuro Diagnostic Devices, Inc., Trevose, Pennsylvania) is a new device designed to detect cerebrospinal fluid (CSF) flow in a shunt by sensing skin temperature downstream from a region of CSF cooled by an ice cube.

OBJECTIVE:

To understand its accuracy and utility, we evaluated the use of this device during routine office visits as well as during workup for suspected shunt malfunction.

METHODS:

One hundred shunted patients were tested, including 48 evaluated during possible shunt malfunction, of whom 24 went on to surgical exploration. Digitally recorded data were blindly analyzed and compared with surgical findings and clinical follow-up.

RESULTS:

Findings in the 20 malfunctioning shunts with unambiguous flow or absence of flow at surgery were strongly correlated with ShuntCheck results (sensitivity and specificity to flow of 80% and 100%, respectively, P = .0007, Fisher's exact test, measure of agreement κ = 0.8). However, the thermal determination did not distinguish patients in the suspected malfunction group who received surgery from those who were discharged without surgery (P = .248 by Fisher's exact test, κ = 0.20). Half of the patients seen in routine office visits did not have detectable flow, although none required shunt revision on clinical grounds. Intermittent flow was specifically demonstrated in one subject who had multiple flow determinations.

CONCLUSION:

Operative findings show that the technique is sensitive and specific for detecting flow, but failure to detect flow does not statistically predict the need for surgery. A better understanding of the normal dynamics of flow in individual patients, which this device may yield, will be necessary before the true clinical utility of non-invasive flow measurement can be assessed.

Initial proximal obstruction of ventriculoperitoneal shunt in patients with preterm-related posthaemorrhagic hydrocephalus

BACKGROUND/AIMS

Obstruction is the most common complication of ventriculoperitoneal shunts in patients with hydrocephalus. Despite technical advances, rates of obstruction have barely decreased and remain at over 40% of cases. Patients suffering from preterm-related posthaemorrhagic hydrocephalus are considered a group with a particularly high risk of obstruction. The aim of the present study was to review our series of patients with preterm-related posthaemorrhagic hydrocephalus and analyse the occurrence of the first ventricular shunt obstruction as well as the related clinical and radiological factors.

METHODS

We conducted a retrospective review of 103 cases treated from 1982 to 2010. Descriptive analysis, raw and adjusted bivariate correlations and survival analysis were performed.

RESULTS

Over the course of the follow-up, 42 patients presented at least one episode of obstruction that required proximal revision. Medium-opening pressure valves were associated with a higher rate of obstruction compared to low-opening pressure valves; however, in our series this association became statistically significant only in patients with a weight of over 2,000 g at the time of surgery (odds ratio 6.75). The occurrence of previous infection and the development of late slit ventricle syndrome were also significantly associated with obstruction of the ventricular catheter (odds ratios 3.35 and 4.27, respectively).

CONCLUSIONS

Rates of shunt obstruction in preterm-related posthaemorrhagic hydrocephalus remain high but do not seem to be higher than in other groups of paediatric hydrocephalus. Prevention of infection and the use of the appropriate type of valve design can help to decrease the incidence of proximal shunt obstruction, which in turn could decrease the incidence of symptomatic slit ventricle syndromes.

Effect of electromagnetic-navigated shunt placement on failure rates: a prospective multicenter study

Object

As many as 40% of shunts fail in the first year, mainly due to proximal obstruction. The role of catheter position on failure rates has not been clearly demonstrated. The authors conducted a prospective cohort study of navigated shunt placement compared with standard blind shunt placement at 3 European centers to assess the effect on shunt failure rates.

Methods

All adult and pediatric patients undergoing de novo ventriculoperitoneal shunt placement were included (patients with slit ventricles were excluded). The first cohort underwent standard shunt placement using anatomical landmarks. All centers subsequently adopted electromagnetic (EM) navigation for routine shunt placements, forming the second cohort. Catheter position was graded on postoperative CT in both groups using a 3-point scale developed for this study: (1) optimal position free-floating in CSF; (2) touching choroid or ventricular wall; or (3) intraparenchymal. Episodes and type of shunt revision were recorded. Early shunt failure was defined as that occurring within 30 days of surgery. Patients with shunts were followed-up for 12 months in the standard group, for a median of 6 months in the EM-navigated group, or until shunt failure.

Results

A total of 75 patients were included in the study, 41 with standard shunts and 34 with EM-navigated shunts. Seventy-four percent of navigated shunts were Grade 1 compared with 37% of the standard shunts (p = 0.001, chi-square test). There were no Grade 3 placements in the navigated group, but 8 in the standard group, and 75% of these failed. Early shunt failure occurred in 9 patients in the standard group and in 2 in the navigated group, reducing the early revision rate from 22 to 5.9% (p = 0.048, Fisher exact test). Early shunt failures were due to proximal obstruction in 78% of standard shunts (7 of 9) and in 50% of EM-navigated shunts (1 of 2).

Conclusions

Noninvasive EM image guidance in shunt surgery reduces poor shunt placement, resulting in a significant decrease in the early shunt revision rate.

Is Normal Pressure Hydrocephalus more than a mechanical disruption to CSF flow?

This work proposes a new theoretical framework for the water transport in the cerebral environment. The approach is based on Multiple-Network Poroelastic Theory (MPET) and is a natural extension of poroelasticity, a well reported technique applied to cerebrospinal fluid (CSF) transport. MPET accounts for the transport of CSF and blood simultaneously, as they permeate and deform the cerebral tissue. To demonstrate the strength of this approach, MPET is applied to one of the most paradoxical and non-intuitive cerebral pathologies, Normal Pressure Hydrocephalus (NPH). It is shown, for the first time, that clinically relevant ventricular deformations can be observed in the case of totally unobstructed, patient-specific aqueducts. Cerebral diseases are recognised as pivotal in healthcare; they relate to a whole host of unmet clinical needs. We are convinced that basic understanding of fluid transport, as provided by a validated MPET model, is the most promising way to address these needs meaningfully, in a clinical setting.

Protective effect of rifampicin and clindamycin impregnated devices against Staphylococcus spp. infection after cerebrospinal fluid diversion procedures

Background

Infection is a major complication of cerebrospinal fluid shunting procedures. The present report assesses the efficacy of such catheters in both shunts and external ventricular drains (EVDs) against infection and particularly against Staphylococcus spp. infection.

Methods

All shunt and EVD procedures performed by means of antibiotic-impregnated catheters (AICs) and non-AICs during the period of study were registered. In cases of shunt procedures, a minimal follow-up of 90 days was considered, as well as de novo insertion and catheter revisions. Single valve revisions were not included. In cases of EVD procedures, those catheters removed before the fifth post-insertion day were not included. A total of 119 cerebrospinal fluid shunting procedures performed with AICs were studied in comparison with 112 procedures performed by means of non-AICs.

Results

Antibiotic-impregnated catheters were associated with a significant decrease in both overall and staphylococcal infection (p = 0.030 and p = 0.045, respectively). The number needed to treat for AICs was 8 to prevent one infection and 14 to prevent one staphylococcal infection. When comparing with shunts, the use of EVDs was associated with a 37-fold increased likelihood of infection.

Conclusions

Antibiotic-impregnated catheters are a safe and helpful tool to reduce CSF shunting device-related infections.

Radiographic assessment of snap-shunt failure: report of 2 cases

Accurate assessment of imaging studies in patients with ventriculoperitoneal shunts can be aided by empirical findings. The authors characterize an objective measurement easily performed on head CT scans with the goal of producing clear evidence of shunt fracture or disconnection in patients with a snap shunt-type system. The authors describe 2 cases of ventriculoperitoneal shunt failure involving a fracture and a disconnection associated with a snap-shunt assembly. In both cases the initial clinical symptoms were not convincing for shunt malfunction, and the interpretation of the CT finding failed to immediately identify the abnormality. As the clinical picture became more convincing for shunt malfunction, each patient subsequently underwent successful shunt revision. The authors reviewed the CT scans of 10 patients with an intact and functioning snap-shunt system to characterize the normal appearance of the snap-shunt connection. On CT scans the distance between the radiopaque portion of the ventricular catheter and the radiopaque portion of the reservoir dome measures an average of 4.72 mm (range 4.6-4.9 mm, 95% CI 4.63-4.81 mm). In the authors' patient with a fractured ventricular catheter, this interval measured 7.8 mm, and in the patient with a disconnection it measured 7.7 mm. In comparison with the range of normal values, a radiolucent interval significantly greater than 4.9 mm should promptly raise concern for a disconnected or fractured shunt in this system. This measurement may prove particularly useful when serial imaging is not readily available.

Endoscopic Third Ventriculostomy Vs Cerebrospinal Fluid Shunt in the Treatment of Hydrocephalus in Children

BACKGROUND

Endoscopic third ventriculostomy (ETV) has preferentially been offered to patients with more favorable prognostic features compared with shunt.

OBJECTIVE

To use advanced statistical methods to adjust for treatment selection bias to determine whether ETV survival is superior to shunt survival once the bias of patient-related prognostic factors is removed.

METHODS

An international cohort of children (≤ 19 years of age) with newly diagnosed hydrocephalus treated with ETV (n = 489) or shunt (n = 720) was analyzed. We used propensity score adjustment techniques to account for 2 important patient prognostic factors: age and cause of hydrocephalus. Cox regression survival analysis was performed to compare time-to-treatment failure in an unadjusted model and 3 propensity score—adjusted models, each of which would adjust for the imbalance in prognostic factors.

RESULTS

In the unadjusted Cox model, the ETV failure rate was lower than the shunt failure rate from the immediate postoperative phase and became even more favorable with longer duration from surgery. Once patient prognostic factors were corrected for in the 3 adjusted models, however, the early failure rate for ETV was higher than that for shunt. It was only after about 3 months after surgery did the ETV failure rate become lower than the shunt failure rate.

CONCLUSIONS

The relative risk of ETV failure is initially higher than that for shunt, but after about 3 months, the relative risk becomes progressively lower for ETV. Therefore, after the early high-risk period of ETV failure, a patient could experience a long-term treatment survival advantage compared with shunt. It might take several years, however, to realize this benefit.

Hydrocephalus shunt practice of experienced pediatric neurosurgeons

OBJECTIVE

The objective of this study is to evaluate the ways experienced pediatric neurosurgeons insert ventriculo-peritoneal shunts and manage the shunted children afterward.

METHODS

Seven pediatric neurosurgeons with extensive experience in hydrocephalus were surveyed about their choice of shunts, methods of shunt insertion, shunt follow-ups, management of incidental ventriculomegaly, and prevention of slit-ventricle syndrome. The author completed the survey also.

RESULTS

No particular shunt was used by a majority of respondents, although differential pressure valves were used most often. Adjuncts to insert the ventricular catheter were used by half. Shunt catheters were inserted frontally in half and posteriorly in half. No one obtained annual follow-up scans after 5 years of age, and no one operated on asymptomatic children with ventriculomegaly except perhaps in spina bifida cases. No techniques were identified to prevent slit-ventricle syndrome, but respondents emphasized the need for reticence in initial shunt insertions and in shunt revisions.

CONCLUSIONS

There are substantial variations among extremely experienced pediatric neurosurgeons in their choice of shunts and their techniques of shunt insertion but reasonable uniformity in their frequency of follow-up, in not-obtaining routine scans after age five, and in rarely revising asymptomatic children. Methods to accurately position ventricular catheters and to prevent slit-ventricle syndrome need to be evaluated in multicenter studies.

Perforation holes in ventricular catheters--is less more?

OBJECTIVE

Obstruction is a common cause of cerebrospinal fluid (CSF) shunt failure. Risk factors for proximal obstructive malfunction are suboptimal ventricular catheter positioning and slit-like ventricles. A new ventricular catheter design to decrease risk of obstruction was evaluated.

METHODS

A review of histopathological tissue investigation from occluded ventricular catheters (n = 70) was performed. A new ventricular catheter design was realized with six perforation holes. These catheters were compared to regular catheters (16 holes, Miethke, Aesculap) for flow characteristics using ink studies and flow velocity at hydrostatic pressure levels from 14 to 2 cmH(2)O in an experimental setup. The six-hole catheters were implanted in hydrocephalic patients with slit-like ventricles (n = 55). A follow-up was performed to evaluate the need of catheter revisions.

RESULTS

Histological evaluation showed that obstructive tissue involved 43-60% extraventricular tissue, including gliosis, connective and inflammatory cells. In flow characteristic studies, the 16-hole catheters showed that only proximal perforations are of functional relevance. For six-hole catheters, all perforations were shown to be relevant with remaining reserve capacity. Flow velocity however showed no significant differences between six and 16 perforations. The six-hole catheter was implanted in 55 patients with a mean follow-up period of 15 +/- 9 months. A total of 12 catheters were explanted, revealing an overall survival proportion of 77.4%.

CONCLUSION

In narrow ventricles, we assume that catheter perforations that are located also in the tissue might be a risk for CSF shunt obstruction. Fewer amounts of perforations in the catheters with equal flow features might decrease this risk when catheters can be implanted with adequate precision.

Endoscopic third ventriculostomy in patients younger than 2 years: outcome analysis of 41 hydrocephalus cases

OBJECT

The object of this study was to analyze the outcome of endoscopic third ventriculostomy (ETV) in patients under 2 years of age and investigate factors related to ETV success or failure in this patient population.

METHODS

The authors reviewed their experience in using endoscopic third ventriculostomy (ETV) in the treatment of 41 hydrocephalus patients younger than 2 years. The mean duration of follow-up was 45 months. The relationship between ETV efficacy and the following variables was analyzed: cause of hydrocephalus, level of CSF occlusion, primary versus secondary ETV, type of surgical procedure, head circumference, patient age at ETV, patient age at first manifestation of hydrocephalus, and anatomical features of the ventricle. Success of ETV was assessed based on the results of neurological examination and postoperative imaging during the follow-up period.

RESULTS

The authors performed 32 primary ETVs and 10 secondary ETVs (ETV after hydrocephalus surgery) in 41 patients (a second ETV was performed in 1 patient). The success rates of primary and secondary ETV were 75.8 and 55.6%, respectively (no significant difference, p = 0.15). The ETV was clinically and radiologically successful in 30 (71.4%) of 42 procedures during a mean (+/- SD) follow-up period of 45.0 +/- 4.8 months (range 12-127 months). A negative relationship was found between success of ETV and the thickness of the floor of the third ventricle (the most effective procedures were those in which the floor of the ventricle was thinnest [p < 0.05]). There was a highly significant correlation between ETV success and prolapse of the ventricle floor (p < 0.001). Also, there was an inverse relationship between ventricle floor thickness and the width of the third ventricle (p < 0.005). In our group of patients there was significant correlation between ETV success and patient age at onset of hydrocephalus (the most effective procedures were in patients in whom signs of hydrocephalus first occurred after 1 month of age [p = 0.02]).

CONCLUSIONS

Endoscopic third ventriculostomy was successful in 71.4% of procedures in children younger than 2 years and in 75.0% of procedures in infants. Success of ETV in children younger than 2 years depends not on the age of the patient or cause of hydrocephalus but on the thickness of the floor of the third ventricle and the patient's age at first manifestation of hydrocephalus.

Shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage: incidence, predictors, and revision rates. Clinical article

OBJECT

Chronic shunt-dependent hydrocephalus is a recognized complication of aneurysmal subarachnoid hemorrhage. While its incidence and risk factors have been well described, the long-term performance of shunts in this setting has not been not widely reported.

METHODS

Using administrative databases, the authors derived a retrospective cohort of patients undergoing treatment of a ruptured aneurysm in Ontario, Canada, between 1995 and 2005. The authors determined the incidence of shunt-dependent hydrocephalus and analyzed putative risk factors. Mortality rates and indicators of morbidity were recorded. Patients were followed up for the occurrence of shunt failure over time.

RESULTS

Of 3120 patients in the cohort, 585 (18.75%) developed shunt-dependent hydrocephalus. On multivariate analysis, age, acute hydrocephalus, ventilation on admission, aneurysms in the posterior circulation and giant aneurysms were all significant predictors of shunt-dependent hydrocephalus. The mortality rate was not increased in patients with chronic hydrocephalus (hazard ratio 1.04, p = 0.63); however, indicators of morbidity were increased in these patients. Of the 585 patients with shunt-dependent hydrocephalus, only 173 (29.6%) underwent a subsequent revision procedure. Ninety-eight percent of these revisions were completed within 6 months. Subsequent revisions occurred more frequently. On multivariate analysis, significant predictors of shunt revision included aneurysm location in the posterior circulation and endovascular treatment of the initial ruptured aneurysm.

CONCLUSIONS

Shunt-dependent hydrocephalus affects a significant proportion of subarachnoid hemorrhage survivors, contributing to additional morbidity among these patients. Shunt failures occur less frequently in patients who underwent treatment for a ruptured aneurysm than with other forms of hydrocephalus. Most failures occur within 6 months, suggesting that shunt dependency may be transient in the majority of patients.

Infection rates following initial cerebrospinal fluid shunt placement across pediatric hospitals in the United States. Clinical article

OBJECT

Reported rates of CSF shunt infection vary widely across studies. The study objective was to determine the CSF shunt infection rates after initial shunt placement at multiple US pediatric hospitals. The authors hypothesized that infection rates between hospitals would vary widely even after adjustment for patient, hospital, and surgeon factors.

METHODS

This retrospective cohort study included children 0-18 years of age with uncomplicated initial CSF shunt placement performed between January 1, 2001, and December 31, 2005, and recorded in the Pediatric Health Information System (PHIS) longitudinal administrative database from 41 children's hospitals. For each child with 24 months of follow-up, subsequent CSF shunt infections and procedures were determined.

RESULTS

The PHIS database included 7071 children with uncomplicated initial CSF shunt placement during this time period. During the 24 months of follow-up, these patients had a total of 825 shunt infections and 4434 subsequent shunt procedures. Overall unadjusted 24-month CSF shunt infection rates were 11.7% per patient and 7.2% per procedure. Unadjusted 24-month cumulative incidence rates for each hospital ranged from 4.1 to 20.5% per patient and 2.5-12.3% per procedure. Factors significantly associated with infection (p < 0.05) included young age, female sex, African-American race, public insurance, etiology of intraventricular hemorrhage, respiratory complex chronic condition, subsequent revision procedures, hospital volume, and surgeon case volume. Malignant lesions and trauma as etiologies were protective. Infection rates for each hospital adjusted for these factors decreased to 8.8-12.8% per patient and 1.4-5.3% per procedure.

CONCLUSIONS

Infections developed in > 11% of children who underwent uncomplicated initial CSF shunt placements within 24 months. Patient, hospital, and surgeon factors contributed somewhat to the wide variation in CSF shunt infection rates across hospitals. Additional factors may contribute to variation in CSF shunt infection rates between centers, but further study is needed. Benchmarking and future prospective multicenter studies of CSF shunt infection will need to incorporate these and other patient, hospital, and surgeon factors.

Endoscopic third ventriculostomy in the treatment of childhood hydrocephalus

OBJECTIVE

To develop a model to predict the probability of endoscopic third ventriculostomy (ETV) success in the treatment for hydrocephalus on the basis of a child's individual characteristics.

STUDY DESIGN

We analyzed 618 ETVs performed consecutively on children at 12 international institutions to identify predictors of ETV success at 6 months. A multivariable logistic regression model was developed on 70% of the dataset (training set) and validated on 30% of the dataset (validation set).

RESULTS

In the training set, 305/455 ETVs (67.0%) were successful. The regression model (containing patient age, cause of hydrocephalus, and previous cerebrospinal fluid shunt) demonstrated good fit (Hosmer-Lemeshow, P = .78) and discrimination (C statistic = 0.70). In the validation set, 105/163 ETVs (64.4%) were successful and the model maintained good fit (Hosmer-Lemeshow, P = .45), discrimination (C statistic = 0.68), and calibration (calibration slope = 0.88). A simplified ETV Success Score was devised that closely approximates the predicted probability of ETV success.

CONCLUSIONS

Children most likely to succeed with ETV can now be accurately identified and spared the long-term complications of CSF shunting.

How long should cerebrospinal fluid cultures be held to detect shunt infections? Clinical article

OBJECT

Infections of CSF hardware may be indolent, and some patients have received antibiotic treatment for various reasons before CSF is obtained to check for a shunt infection. At present, there are few data in the literature to guide the decision as to how long to hold CSF specimens when attempting to diagnose hardware infections, and institutions vary in the duration at which cultures are considered "final."

METHODS

The authors reviewed the microbiology data from CSF specimens obtained from shunts, ventriculostomies, reservoirs, and lumbar drains at their institution over a 36-month period to discover how long after collection cultures became positive. The authors also sought to discover whether this time was affected by prior treatment with antibiotics.

RESULTS

Of 158 positive CSF specimens obtained from hardware, the time to recovery ranged between 1-10 days, with a mean of 3.02 days (SD 2.37 days, 95% CI 2.66-3.38 days). One hundred and twenty-seven positive specimens were associated with clinical infections, and approximately 25% of these grew organisms after > 3 days, with some as long as 10 days after specimens were obtained. The most common organisms grown from individual patients were coagulase-negative Staphylococcus spp (34 cultures), Propionibacterium spp (21), Bacillus spp (6), Pseudomonas aeruginosa (4), and Staphylococcus aureus (4 cultures). Mean and maximum days to recovery were different across species, with S. aureus showing the shortest and Propionibacterium spp showing the longest incubation times. There appeared to be no significant difference in the time to recovery between specimens obtained in patients who had received prior antibiotic treatment versus those who had not.

CONCLUSIONS

A substantial number of positive CSF specimens obtained in patients with clinical infections grew bacteria after > 3 days, with some requiring as long as 10 days. Thus, a routine 10-day observation period for CSF specimens can be justified.

Treatment of hydrocephalus in adults

The following patients with multiple complex diagnoses define the adult hydrocephalus population: (1) transition patients (previously treated for hydrocephalus as children), (2) adults with previously untreated congenital hydrocephalus, (3) adults with acquired hydrocephalus with an identifiable etiology, and (4) patients with suspected or proven idiopathic normal pressure hydrocephalus. Restricting the outpatient care or hydrocephalus clinic definition to a single hydrocephalus patient subpopulation limits our understanding of these patients and effectively abandons the remaining adult patients with hydrocephalus to a less focused and potentially less effective healthcare arrangement. A comprehensive adult hydrocephalus clinic model is described and recommended to advance our understanding of this diverse patient population, which will ultimately lead to the development and provision of a better standard of patient care.

Gravitational shunt units may cause under-drainage in bedridden patients

OBJECTIVE

Implantation of a shunt in a hydrocephalic patient still carries a risk of complications such as over-drainage and under-drainage. Gravitational shunt units are especially designed to minimize the problem of over-drainage. Nevertheless, these valves carry a risk of under-drainage. The best choice of valve for a patient is still challenging. The purpose of this survey was to identify in which patients a gravitational shunt valve is liable to lead to under-drainage.

METHODS

Patients with hydrocephalus entered prospectively into a data base were reviewed retrospectively. The patients were treated between January 2006 to the end of Feb 2007 and those experiencing under- or over-drainage were identified.

RESULTS

Thirty-five ventriculo-peritoneal shunt systems were implanted in adult patients. The cause of the hydrocephalus was: normal pressure hydrocephalus in 18 patients, post-haemorrhagic following subarachnoid or intracerebral haemorrhage in 11, associated with a tumour in four and followed a head injury in two patients. Three different valves were used: an adjustable shunt valve with gravitational unit (Pro-GAV 0-20/25 in 21 patients), a gravitational shunt valve with fixed opening pressure (GAV 5/30 in nine patients) and an adjustable differential valve (Hakim medos in five patients). Four patients developed severe, valve-related under-drainage. Each had received a gravitational shunt valve and all were bedridden. In two of these patients it was necessary to change the valve. One patient who had received a differential valve, after regaining mobility developed severe over-drainage with bilateral subdural haematomas. Over-drainage was not seen in long-term bedridden patients with a differential shunt valve.

CONCLUSION

If a bedridden patient with a gravitational shunt valve system lies with a slightly elevated head, this leads to activation of the gravitational unit and this may cause under drainage. As a result, we advise not using an anti-siphon devices in a patient who is bedridden for a long period.

Priorities for hydrocephalus research: report from a National Institutes of Health-sponsored workshop

OBJECT

Treatment for hydrocephalus has not advanced appreciably since the advent of cerebrospinal fluid (CSF) shunts more than 50 years ago. Many questions remain that clinical and basic research could address, which in turn could improve therapeutic options. To clarify the main issues facing hydrocephalus research and to identify critical advances necessary to improve outcomes for patients with hydrocephalus, the National Institutes of Health (NIH) sponsored a workshop titled "Hydrocephalus: Myths, New Facts, and Clear Directions." The purpose of this paper is to report on the recommendations that resulted from that workshop.

METHODS

The workshop convened from September 29 to October 1, 2005, in Bethesda, Maryland. Among the 150 attendees was an international group of participants, including experts in pediatric and adult hydrocephalus as well as scientists working in related fields, neurosurgeons, laboratory-based neuroscientists, neurologists, patient advocates, individuals with hydrocephalus, parents, and NIH program and intramural staff. Plenary and breakout sessions covered injury and recovery mechanisms, modeling, biomechanics, diagnosis, current treatment and outcomes, complications, quality of life, future treatments, medical devices, development of research networks and information sharing, and education and career development.

RESULTS

The conclusions were as follows: 1) current methods of diagnosis, treatment, and outcomes monitoring need improvement; 2) frequent complications, poor rate of shunt survival, and poor quality of life for patients lead to unsatisfactory outcomes; 3) investigators and caregivers need additional methods to monitor neurocognitive function and control of CSF variables such as pressure, flow, or pulsatility; 4) research warrants novel interdisciplinary approaches; 5) understanding of the pathophysiological and recovery mechanisms of neuronal function in hydrocephalus is poor, warranting further investigation; and 6) both basic and clinical aspects warrant expanded and innovative training programs.

CONCLUSIONS

The research priorities of this workshop provide critical guidance for future research in hydrocephalus, which should result in advances in knowledge, and ultimately in the treatment for this important disorder and improved outcomes in patients of all ages.

The surgical management of pediatric hydrocephalus

The surgical management of hydrocephalus has undergone incredible changes over the past generation of neurosurgeons, including dramatic improvements in imaging, especially computed tomographic scanning and magnetic resonance imaging, and remarkably innovative advances in cerebrospinal fluid valve technology, complex computer models, and endoscopic equipment and techniques. In terms of overall patient outcomes, however, one could conclude that things are a little better, but "not much." This frustrating yet fascinating dichotomy between technological advancements and clinical outcomes makes hydrocephalus, first described by the ancients, as one of the most understated and complex disorders that neurosurgeons treat. The challenge to the next generation of neurosurgeons is to solve this vexing problem through better understanding of the basic science, improved computer models, additional technological advances, and, most importantly, a broad-based, concerted multidisciplinary attack on this disorder. This review focuses on the evolution of surgery for hydrocephalus over the last 30 years, the current state of the art of hydrocephalus treatment, and what appear to be the most promising future directions.

LOWER INCIDENCE OF REOPERATION WITH LONGER SHUNT SURVIVAL WITH ADULT VENTRICULOPERITONEAL SHUNTS PLACED FOR HEMORRHAGE-RELATED HYDROCEPHALUS

OBJECTIVE

The incidence of reoperation for ventriculoperitoneal shunts (VPS) in adults, although lower than in pediatric patients, is not insignificant. We hypothesize that adult VPS placed for hemorrhage-related hydrocephalus have a lower incidence of reoperation than those placed for other types of hydrocephalus.

METHODS

We retrospectively reviewed all adult (≥ 20 yr) VPS initially placed from February 2001 to August 2006 at the University of Florida. We determined the incidence and time interval to reoperation. Follow-up was conducted by telephone interview and review of medical records.

RESULTS

A total of 286 adult VPS were initially placed: 96 (34%) hemorrhage and 190 (66%) nonhemorrhage. A total of 15 (16%) hemorrhage patients underwent 22 shunt reoperations, compared with 50 (27%) nonhemorrhage patients who underwent 82 shunt reoperations (P = 0.0316). A Poisson regression analysis of the number of reoperations, factoring hemorrhage, age, and sex, demonstrated a significantly lower incidence of reoperation in hemorrhage patients (P = 0.0900). A Cox proportional hazards model analysis of time to first reoperation, factoring hemorrhage, age, and sex, demonstrated a significantly longer shunt survival in hemorrhage patients (P = 0.0404).

CONCLUSION

Adult VPS placed for hemorrhage-related hydrocephalus have a significantly lower incidence of reoperation and significantly longer shunt survival. This result may be related to an incidence of transient shunt dependency in patients with hemorrhage-related hydrocephalus. However, the precise mechanism remains unclear.

A multi-institutional, 5-year analysis of initial and multiple ventricular shunt revisions in children

OBJECTIVE

To evaluate risk factors and predictors of cerebrospinal ventricular shunt revisions in children.

METHODS

A retrospective, longitudinal cohort of 1307 children ages 0 to 18 years undergoing initial ventricular shunt placement in the year 2000, with follow-up through 2005, from 32 freestanding children's hospitals within the Pediatric Health Information Systems database was studied. Rates of ventricular shunt revision were compared with patient demographic, clinical, and hospital characteristics with use of bivariate and multivariate regression accounting for hospital clustering.

RESULTS

Thirty-seven percent of children required at least one shunt revision within 5 years of initial shunt placement; 20% of children required two or more revisions. Institutional rates of first shunt revision ranged from 20 to 70% of initial shunts placed among the 32 hospitals in the cohort. Hospitals where one to 20 initial shunt placements per year experienced the highest initial shunt revision rate (42%). Hospitals performing over 83 initial shunt placements per year experienced the lowest revision rate (22%). We found that children undergoing shunt placement in the Midwest were more likely to experience multiple shunt revisions (odds ratio, 1.25; 95% confidence interval, 1.06-1.47) after controlling for hospital volume, shunt type, age, and diagnosis associated with initial shunt placement.

CONCLUSION

Higher hospital volume of initial shunt placement was associated with lower revision rates. Substantial hospital variation in the rates of ventricular shunt revision exists among children's hospitals. Future prospective studies are needed to examine the reasons for the variability in shunt revision rates among hospitals, including differences in specific processes of care.

Ventricular shunt tap as a predictor of proximal shunt malfunction in children: a prospective study

OBJECT

The clinical diagnosis of cerebrospinal fluid (CSF) shunt malfunction can be challenging. In this prospective study, the authors evaluated a common method of interrogating shunts: the shunt tap; specifically, its ability to predict proximal malfunction.

METHODS

The authors performed standardized shunt taps in a consecutive series of cases involving children with suspected or proven shunt malfunction, assessing flow and, when possible, opening pressure. Data were collected prospectively, and results analyzed in light of surgical findings.

RESULTS

A shunt tap was performed prior to 68 operative explorations in 51 patients. Of the 68 taps, 28 yielded poor or no CSF flow on aspiration. After 26 of these 28 procedures, proximal catheter obstruction was identified. After 28 taps with good CSF return and normal or low opening pressure, 18 shunts were found to have a proximal obstruction, 8 had no obstruction, and 2 had a distal obstruction. Another 12 taps with good CSF flow had high opening pressure; subsequent surgery showed distal obstruction in 11 of the shunts, and proximal obstruction in 1. The positive predictive value of poor flow was 93%, while good flow on shunt tap predicted adequate proximal catheter function in only 55% of cases.

CONCLUSIONS

Poor flow of CSF on shunt tap is highly predictive of obstruction of the proximal catheter. Because not all patients with good flow on shunt tap underwent surgical shunt exploration, the specificity of this test cannot be determined. Nonetheless, a shunt tap that reveals good flow with a normal opening pressure can be misleading, and management of such cases should be based on clinical judgment.

Endoscopic management of hydrocephalus in pediatric patients: a review of indications, techniques, and outcomes

Although ventriculoperitoneal shunting remains the treatment of choice for many children with hydrocephalus, advances in endoscopic technology have greatly expanded the treatment options for these patients. For selected patients with obstructive hydrocephalus, endoscopic third ventriculostomy and other endoscopic techniques offer substantial advantages over shunting. As with any surgical procedure, appropriate patient selection is critical to successful outcomes. This article reviews modern endoscopic techniques available to treat hydrocephalus, with a focus on selection criteria and outcomes.

Clinical diagnosis of ventriculoperitoneal shunt failure among children with hydrocephalus

OBJECTIVE

To define the significance of various symptoms and signs in the diagnosis of ventriculoperitoneal shunt failure and infection.

METHODS

The observations that form the basis of this study were made in the course of 2 multicenter, prospective, randomized, controlled clinical trials of technical aspects of ventriculoperitoneal shunt surgery-the Shunt Design Trial and the Endoscopic Shunt Insertion Trial. At registration, basic demographic and baseline clinical data were recorded. At scheduled follow-up visits 3 months and 1, 2, and 3 years after surgery and at unscheduled visits, the presence or absence of various symptoms or signs was recorded. At each visit, the neurosurgeon-investigator made a determination about whether the shunt had reached an end point: mechanical obstruction, infection, overdrainage, or loculation of the ventricular system. Observations at the last follow-up visit for each patient constituted the data for the current study. Sensitivities, specificities, and likelihood ratios were calculated for each symptom and sign as tests for shunt failure from any cause and for failure by infection. Decision trees were constructed to analyze the relationships of various symptoms and signs in the diagnosis of shunt failure and infection.

RESULTS

Observations were available for analysis from 647 patient visits. A total of 248 shunts were judged to have failed (38%), and 55 were judged specifically to have failed by infection (8.5%). Bulging fontanel, fluid collection along the shunt, depressed level of consciousness, irritability, abdominal pain, nausea and vomiting, abnormal shunt pump test, accelerated head growth, and headache were strongly associated with shunt failure. Fever was strongly associated with shunt infection. Gross signs of wound infection were associated with shunt infection but were observed infrequently. Decision tree analysis confirmed the salience of bulging fontanel as a predictor of shunt failure. Fever and time since initial surgery were powerful predictors of shunt infection. Irritability emerged as an important observation in the identification of both shunt failure and shunt infection. Among children who underwent initial shunt insertion after 2 months of age, the absence of irritability, nausea/vomiting, and headache were powerful and generalizable predictors of the absence of shunt failure or infection.

CONCLUSIONS

Analysis of symptoms and signs of ventriculoperitoneal shunt complications can inform clinical judgment in the assessment of children with hydrocephalus.

VENTRICULOPERITONEAL SHUNTING AFTER ANEURYSMAL SUBARACHNOID HEMORRHAGE

OBJECTIVE

The goals of this study were to investigate the risk factors, indications, complications, and outcome for patients with ventriculoperitoneal shunts (VPSs) after subarachnoid hemorrhage and to define a subgroup eligible for future prospective studies designed to clarify indications for placement of a VPS.

METHODS

Clinical characteristics of 236 prospectively evaluated patients with subarachnoid hemorrhage and 6 months of follow-up were analyzed. Hydrocephalus was estimated by the relative bicaudate index (RBCI) measured on computed tomographic scans at the time of shunting. Patients were divided into three groups by ventricle size: Group 1 included 121 patients with small ventricles (RBCI &lt;1.0), Group 2 included 88 patients with borderline ventricle size (RBCI 1.0–1.4), and Group 3 included 27 patients with markedly enlarged ventricles (RBCI &gt;1.4).

RESULTS

Initially, 86 patients (36%) underwent ventriculoperitoneal shunting: 19 in Group 1 (16%), 43 in Group 2 (49%), and 24 in Group 3 (90%). Indications for placement of a VPS, risk factors, and outcome differed markedly by group. Four patients (3% of those not initially shunted) developed delayed hydrocephalus requiring a VPS, including one in Group 2 (2%). The 6-month shunt complication rate was 13%. Evaluation of patients in Group 2 indicated that functional status was an important factor in selecting candidates for shunting, and that patients receiving shunts and shunt-free patients demonstrated improvement in functional status during follow-up.

CONCLUSION

Although we currently use a proactive shunting paradigm for posthemorrhagic hydrocephalus, this report demonstrates that a conservative approach to patients with borderline ventricle size (i.e., RBCI of 1.0–1.4) and normal intracranial pressure should be evaluated in a prospective randomized trial.

Monte Carlo simulation of cerebrospinal fluid shunt failure and definition of instability among shunt-treated patients with hydrocephalus

OBJECT

The authors undertook the present study to estimate the number of operations that patients with hydrocephalus will require within 10 years of diagnosis based on published survival data for cerebrospinal fluid (CSF) shunts.

METHODS

Survival data for CSF shunts from several previously published sources were formatted as life tables spanning a 10-year period in monthly intervals. The monthly sequence of fractions of shunts failing was taken as the basis for a Monte Carlo simulation. Month by month for each virtual patient the computer simulation called up a random number between 0 and 1. If the random number was greater than the fraction of shunts failing in that monthly interval, the shunt survived. If the random number was less than or equal to the fraction of shunts failing in that interval, the shunt failed. When a virtual patient's shunt failed, that patient was returned to the first interval in the life table and began again. For every virtual patient this process continued for 120 months, and the number of shunt operations during the 10-year epoch was counted. Probability distributions were estimated for numbers of shunt operations. Expected numbers of shunt operations were calculated, as were the 95th and 99th percentiles.

RESULTS

Four sources of CSF shunt survival data were used. Expected numbers of shunt operations ranged between 2.43 and 3.93 over 10 years. Estimated 95th percentiles ranged between five and 11, and estimated 99th percentiles ranged between eight and 15.

CONCLUSIONS

New patients with hydrocephalus can expect to undergo between two and four operations for insertion or revision of CSF shunts in the first 10 years after diagnosis. Patients who undergo more than 15 shunt operations in 10 years are statistical outliers. A focused study of such patients may yield useful suggestions for complication avoidance and improvement in the quality of life of children with hydrocephalus.

Laparoscopic versus non-laparoscopic-assisted ventriculoperitoneal shunt placement in adults. A retrospective analysis

BACKGROUND

Ventriculoperitoneal shunts and distal shunt revisions bear a high risk of distal malfunction, especially in patients with previous abdominal pathologies as well as in obese patients. We performed laparoscopy-guided distal shunt placement or revision for patients with and without a positive abdominal history. We review the indications, techniques, complications, and long-term outcomes of these cases and compare the results to those of patients operated without laparoscopic guidance.

METHODS

A total of 211 distal shunt procedures were performed in our institute between January 2001 and December 2005, 59 of which were laparoscopically guided, and 152 were not. Of the 211 procedures, 177 were placement of new shunt systems, and 34 were distal revisions. A total of 33 procedures were performed in 25 patients with a history of abdominal surgery or inflammatory bowel disease; 15 procedures were operated with laparoscopic guidance.

RESULTS

The short-term complication and outcome rates were similar between the laparoscopy group and the other patients. Among the patients with new shunts, the long-term distal malfunction rate was lower in the laparoscopy group compared with the nonlaparoscopy group (4% vs 10.3%, respectively; P = .17). No patients in the laparoscopy group and 6 patients operated by other techniques had distal malfunction. There was 1 laparoscopy-related mortality and no morbidity.

CONCLUSIONS

Laparoscopy is not routinely indicated in distal shunt placement or revision. However, a laparoscopy-guided procedure may lower the rate of distal malfunction in patients with previous abdominal surgeries.

Laparoscopic Peritoneal Catheter Placement: Results of a New Method in 111 Patients

Objective:

Although cerebrospinal fluid shunting remains one of the most common neurosurgical procedures, it is fraught with high infection, blockage, and reoperation rates. It has been estimated that the economic cost of ventriculoperitoneal shunting exceeds $1 billion annually. A new laparoscopic technique that eliminates abdominal incisions overlying shunt hardware was applied to 111 patients requiring ventriculoperitoneal shunts in an effort to decrease the morbidity associated with shunting.

Methods:

All patients who required ventriculoperitoneal shunt insertion were eligible for this surgical technique. Patient selection was based on availability of both surgical teams (general surgery and neurological surgery) at the time of surgery. Using this technique, the distal shunt catheter is tunneled directly from the head into the peritoneal cavity under laparoscopic guidance without a skin incision directly overlying the distal catheter insertion site. Patients were followed prospectively for signs and symptoms related to shunt dysfunction, shunt infection, and incision morbidity.

Results:

One hundred eleven patients underwent 113 laparoscopic ventriculoperitoneal shunt surgeries between February 2003 and December 2004. The average follow-up period was 21.7 months (range, 12–34 mo). Nearly half of the patients (49%) were discharged the next morning and the majority (81%) was discharged within 2 days of surgery. Overall, 15 patients experienced complications requiring reoperation (13.5%) with a 1-year shunt survival rate of 91%. One patient (0.9%) acquired a new shunt infection, whereas two patients (1.8%) developed recurrence from a previous shunt infection. There were no abdominal incision-related complications.

Conclusion:

This simplified laparoscopic shunt placement technique, which requires no overlying abdominal incisions, can be performed quickly with high shunt survivability and low infection rates. Furthermore, the laparoscopic method has the advantage of fast recovery time, elimination of preperitoneal or misplaced catheters, and decreased abdominal incision morbidity. The procedure can be performed by either a multidisciplinary team or entirely by neurosurgeons.

Test characteristics of parent's visual analog scale score in predicting ventriculoperitoneal shunt malfunction in the pediatric emergency department

OBJECTIVES

Many parents of children with ventriculoperitoneal shunts present to the emergency department for evaluation of a possible shunt malfunction. No study to date has evaluated their ability to predict a shunt malfunction. Our study objective was to evaluate parents' accuracy for predicting a shunt malfunction in their child. We hypothesize that parents more experienced with prior shunt malfunctions are better able to predict subsequent malfunctions in their child.

METHODS

We conducted a prospective, descriptive study on children younger than 18 years presenting to our tertiary care pediatric emergency department with a possible ventriculoperitoneal shunt malfunction. Parents rated the likelihood of a shunt malfunction using an unmarked 100-mm visual analog scale marked definitely malfunctioning at the high end. An experienced parent was defined as one who had previously experienced at least 3 shunt malfunctions in their child.

RESULTS

We enrolled 85 parent-child dyads in our study. Twenty-four children were diagnosed with a malfunction. The predictive ability of parents to determine a shunt malfunction was found at a threshold visual analog scale score of 66 (sensitivity, 88.9%, and specificity, 62.2%). At a determined threshold value of 85 or more, experienced parents had a high specificity of 89.2% with a positive likelihood ratio of 5.1. Experienced parents showed an area under the curve of 0.7928 (95% confidence interval, 0.6037-0.9819); and inexperienced parents, 0.5611 (95% confidence interval, 0.3646-0.7576) (P = 0.096).

CONCLUSIONS

Experienced parents are better able to predict a shunt malfunction in their child.