Time Of Shunt Insertion Research Articles

Impact of dual procedures: How combining VP shunt placement for hydrocephalus and myelomeningocele repair in newborns affects complication rates?

To discern the efficacy of simultaneous versus delayed VPS surgery in managing hydrocephalus linked with MMC repair: The debate over the concurrent or deferred placement of ventriculoperitoneal shunts (VPS) during myelomeningocele (MMC) repair in hydrocephalic neonates necessitates a nuanced evaluation of associated risks and benefits. While VPS placement can mitigate cerebrospinal fluid (CSF) leaks and minimize wound dehiscence post-MMC repair, it concurrently introduces potential hazards such as infections and shunt-related malfunctions. This prospective cohort study focused on144 newborns with spinal myelomeningocele and hydrocephalus. Divided into two groups based on the timing of dysraphism repair and VPS placement, 101 children underwent concurrent procedures, while 43 received deferred VPS insertion post-MMC closure. Female patients constituted 60% of the cohort, with lumbar lesions being predominant. The median age for MMC closure was three days. Analysis revealed that the deferred insertion group exhibited higher rates of shunt malfunctions, CSF leaks, and wound dehiscence compared to the concurrent insertion group. Although indications hinted at a potential increase in shunt infections in the immediate insertion group, statistical significance was lacking. The study established a statistically significant association between the timing of shunt insertion during MMC repair and specific outcomes, such as CSF leaks and wound dehiscence. The findings suggest that concurrent shunt insertion during MMC repair may reduce the incidence of these complications compared to deferred insertion. However, no substantial differences emerged in terms of shunt infection and malfunction, emphasizing the persistent challenges associated with these major complications.

Ventriculoperitoneal shunting obstruction: a multicentre clinical audit for cerebrospinal fluid parameters and its prediction role.

Shunt obstruction is a type of ventriculoperitoneal shunt (VPS) failure. Whether changes in cerebrospinal fluid (CSF) parameters can influence shunt outcomes or not is debatable. In this study, we retrospectively included adult hydrocephalus patients who received VPS from 6 general hospitals in different provinces of China from November 2013 to September 2021. The inclusion criteria: Patients with hydrocephalus of all etiologies underwent shunt surgery from 6 general hospitals in different provinces of China were included in the study. The exclusion criteria: 1.Patients under the age of 18; 2.Patients who had previous shunt surgery; 3. Shunt failurefromother factors; 4.Patients died from other causes; 5. Patients with incomplete data. The CSF of shunt patients had been analyzed at the time of shunt insertion. The CSF samples were collected and analyzed when the shunt was implanted. The relationship between CSF parameters and the incidence rate of shunt obstruction in one year was analyzed. A total of 717 eligible patients from 6 hospitals were included, of whom 59(8.23%) experienced obstruction. Multivariate logistic regression analysis identified that protein level(odds ratio [OR] 1.161, 95% CI 1.005 ~ 1.341, p = 0.043), decreased glucose level(< 2.5 mmol/L)(odds ratio 3.784, 95% confidence interval 1.872 ~ 7.652, p = 0.001) and protein level increase(> 0.45 g/L) (odds ratio 3.653, 95% confidence interval 1.931 ~ 6.910, p = 0.001)were independent risk factors of shunt obstruction. This study suggested that increased protein level (> 0.45 g/L) and decreased glucose level (< 2.5 mmol/L) in CSF indicated an increased risk of shunt obstruction in a patient with hydrocephalus. Thus, shunt surgery should be more carefully considered when the CSF glucose and protein were abnormal.

Risk Factors for Malfunction of Ventriculoperitoneal Shunts Performed by Medical Residents in Children: An Exploratory Study

Abstract Introduction Ventriculoperitoneal shunts (VPSs) are common neurosurgical procedures, and in educational centers, they are often performed by residents. However, shunts have high rates of malfunction due to obstruction and infection, especially in pediatric patients. Monitoring the outcomes of shunts performed by trainee neurosurgeons is important to incorporate optimal practices and avoid complications. Methods In the present study, we analyzed the malfunction rates of VPSs performed in children by residents as well as the risk factors for shunt malfunction. Results The study included 37 patients aged between 0 and 1.93 years old at the time of surgery. Congenital hydrocephalus was observed in 70.3% of the patients, while 29.7% showed acquired hydrocephalus. The malfunction rate was 54.1%, and the median time to dysfunction was 28 days. Infections occurred in 16.2% of the cases. Cerebrospinal fluid leukocyte number and glucose content sampled at the time of shunt insertion were significantly different between the groups (p = 0.013 and p = 0.007, respectively), but did not have a predictive value for shunt malfunction. In a multivariate analysis, the etiology of hydrocephalus (acquired) and the academic semester (1st) in which the surgery was performed were independently associated with lower shunt survival (p = 0.009 and p = 0.026, respectively). Conclusion Ventriculoperitoneal shunts performed in children by medical residents were at a higher risk of malfunction depending on the etiology of hydrocephalus and the academic semester in which the surgery was performed.

Modelling success after perinatal post-haemorrhagic hydrocephalus: a single-centre study

IntroductionPost-haemorrhagic hydrocephalus is common amongst premature infants and one of the leading indications for paediatric cerebrospinal fluid (CSF) diversion. Permanent CSF diversion is often delayed until the infant is older but there is no clear consensus on the timing for this. The outcomes for permanent shunting in this patient group are poor, with higher rates of failure and infection compared to other aetiologies of hydrocephalus.MethodsWe conduct a single-centre retrospective review of infants with post-haemorrhagic hydrocephalus requiring a permanent shunt insertion over a 5-year period. Demographic and clinical data from time of shunt insertion were collected and used to generate generalised linear models (GLMs) to predict shunt success at 12 months after insertion.ResultsTwenty-six infants underwent permanent shunting in this period for post-haemorrhagic hydrocephalus, with 10 suffering shunt failure within the first 12 months. The best-performing GLM was able to predict shunt success with a sensitivity of 1 and specificity of 0.90, with head circumference, weight, and corrected age at the time of shunt insertion being the most significantly associated variables for shunt success in this model.ConclusionOur proof-of-principle study suggests that highly accurate prediction of shunt success for infants with post-haemorrhagic hydrocephalus is possible using routinely available clinical variables. Further work is required to test this model in larger cohorts and validate whether pre-operative use can improve outcomes for this patient group.

Association of Preoperative Cerebrospinal Fluids Parameters With Early Shunt Obstruction in Patients With Post-hemorrhagic Hydrocephalus Treated by Lumboperitoneal Shunt.

Background: Early shunt obstruction (SO) remains the most common cause of lumboperitoneal shunt (LPS) failure. Although there is anecdotal evidence that the level of cerebrospinal fluid (CSF) parameters might affect shunt performance, its association with early LPS obstruction in adults with post-hemorrhagic hydrocephalus (PHH) is unclear.Methods: The retrospective study was performed by reviewing the adults with PHH treated by LPS from years 2014 to 2018. We included patients with CSF samples analyzed within 1 week prior to shunt insertion or at the time of shunt insertion. Baseline characteristics of each patient were collected. The primary outcomes were the incidence rate and associated factors of SO occurring within 3 months of shunt placement. The secondary outcomes included scores on the National Institute of Health Stroke Scale (NIHSS) and Evans Index at discharge.Results: A total of 76 eligible patients were analyzed, of whom 61 were obstruction-free and 15 were early SO. The overall rate of early SO was 15.6%. The RBCs count and nucleated cells count in preoperative CSF were actually higher in patients with early SO, compared to patients in the control group. Multivariate analysis identified RBC elevation (>0 × 106/L; OR: 10.629, 95% CI: 1.238–91.224, p = 0.031) as a dependent risk factor for early SO. NIHSS dramatically decreased at discharge while the alteration of ventricular size was not observed.Conclusions: This study suggested that the presence of RBCs in preoperative CSF was associated with early SO in patients with PHH treated by LPS.

CSF shunt valve occlusion-does CSF protein and cell count matter?

Shunt obstruction is a common cause of shunt failure in the treatment of hydrocephalus. Valve occlusion is traditionally believed to originate from elevated CSF protein or cellular components, although detailed evidence is scarce and contradictory. Therefore, this study aimed to examine CSF protein and cell count as risk factors for valve obstruction. We retrospectively examined 274 patients who underwent shunt placement for hydrocephalus between 2009 and 2018 and had at least 1year follow-up. Age, aetiology of hydrocephalus, valve type, occurrence of revision, reason for revision and CSF protein and cell count at the time of shunt insertion and revision surgery were analysed. Thirty-two of 274 patients (11.7%) required revision surgery due to valve occlusion. Mean time to revision was 143days. CSF white blood cell (WBC) count but not protein was associated with valve occlusion overall. Of all obstructed valve patients, 25% showed CSF protein level within the normal range, whereas 13.6% of the patients overall showed greatly elevated CSF protein level without evidence of valve obstruction. Persistently elevated CSF protein level at the time of shunt revision was significantly associated with valve obstruction within 90days of initial insertion (early occlusion). Children with congenital malformations and post-haemorrhagic patients were significantly overrepresented in the occlusion group, particularly in the early occlusion group. Pathological CSF values such as WBC count and persistently elevated protein level serves as a risk factor for early valve obstruction. Late obstruction occurs independent of normal CSF values. Infants are particularly prone to early and late valve obstructions. CSF protein level at shunt insertion is not predictive of valve occlusion.

CSF Surfactant Protein Changes in Preterm Infants After Intraventricular Hemorrhage.

Introduction: Surfactant proteins (SP) have been shown to be inherent proteins of the human CNS and are altered during acute and chronic disturbances of CSF circulation. Aim of the study was to examine the changes of surfactant protein concentrations in CSF of preterm babies suffering from intraventricular hemorrhage.Patients and Methods: Consecutive CSF samples of 21 preterm infants with intraventricular hemorrhages (IVH) and posthemorrhagic hydrocephalus (PHHC) were collected at primary intervention, after 5–10 days and at time of shunt insertion ~50 days after hemorrhage. Samples were analyzed for surfactant proteins A, B, C, and G by ELISA assays and the results were compared to 35 hydrocephalus patients (HC) without hemorrhage and 6 newborn control patients.Results and Discussion: Premature patients with IVH showed a significant elevation of surfactant proteins SP-A, C, and G compared to HC and control groups: mean values for the respective groups were SP-A 4.19 vs. 1.08 vs. 0.38 ng/ml. Mean SP-C 3.63 vs. 1.47 vs. 0.48 ng/ml. Mean SP-G 3.86 vs. 0.17 vs. 0.2 ng/ml. SP-A and G concentrations were slowly falling over time without reaching normal values. SP-C levels declined faster following neurosurgical interventions and reached levels comparable to those of hydrocephalus patients without hemorrhage.Conclusion: Intraventricular hemorrhages of premature infants cause posthemorrhagic CSF flow disturbance and are associated with highly significant elevations of surfactant proteins A, C, and G independent of total CSF protein concentrations.

Timing of Shunt Insertion in Children with Neural Tube Defects and Hydrocephalus: A Clinical Study.

Timing of Shunt Insertion in Children with Neural Tube Defects and Hydrocephalus: A Clinical Study.

Shunting of the over 80s in normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus is predominantly a disease of the elderly. By its nature, many of those who present to clinic are in advanced old age with multiple comorbidities. Majority of patients treated are younger than 80years old. We present the clinical outcomes and complication rates of patients over the age of 80years at the time of operation, during the past 11years at a single institution. Retrospective analysis of clinical records of all patients over the age of 80years, who presented to our institution between 2006 and 2016. Results were analysed for co-morbidities, immediate and delayed complications, change in mobility/cognitive function post shunting of hydrocephalus. 39 patients (24 male, 15 female) met criteria. Mean [SD] age at the time of shunt insertion was 84years (+/- 3.22) (range 80-94). No patients developed immediate CSF infection or sub-dural collection, or extended length of stay due to surgical or anaesthetic complications. There were no peri-operative or anaesthetic complications. 4 patients required a delayed surgical revision to encourage greater CSF drainage. 3 patients went on to develop delayed subdural haematoma, 1 of which was associated with trauma, 2 through overdrainage. 1 patient experienced poor post-operative wound healing and subsequently underwent removal of shunt. Of the 34 patient followed up, 27 patients (79.4%) improved in their mobility. (64.7%) patients/families reported symptomatic improvement in their cognition and memory. 6 (17.7%) patients did not experience an improvement in either mobility or cognitive function. Our data supports the assertion that, with proper patient selection, shunting of the over 80s with iNPH is a safe and effective procedure.

Shunt infection in the first year of life

Children younger than 1 year of age are unique in their physiology and comorbidities. Reports in the literature suggest that the risk factors for shunt infection may be different in this population compared with older children. Importantly, these infants often have other congenital malformations requiring various surgical interventions, which impose an additional risk of infection. In the 3-year period between 2008 and 2010, 270 patients underwent initial CSF shunt placement during the 1st year of life. Clinical characteristics, hospital course, and shunt infections were prospectively recorded in the practice and hospital electronic medical record. Special attention was given to types and timing of other invasive procedures and their relationship with shunt infection. The average gestational age was 33.6 weeks, and the average birth weight was 2333 g. The average weight at the time of shunt insertion was 4281 g. Prior to shunt insertion, 120 patients underwent 148 surgical procedures, including ventricular access device insertion (n = 63), myelomeningocele closure (n = 37), and cardiac procedures (n = 11), among others. In the 12-month period after shunt insertion, 121 of the 270 patients underwent 135 surgical procedures, which included 79 CSF shunt revisions. Shunt infection occurred in 22 patients, and organisms were identified in 20 cases. Univariate analysis showed that of the very prematurely born infants (gestational age < 30 weeks), those who underwent preshunt cardiac surgery and any surgical procedures within 30 days after the shunt insertion were at a greater risk of shunt infection. In multivariate analysis, preshunt cardiac surgery and surgical procedures within 30 days postshunt placement were significant risk factors independent of gestational age, birth weight, and history of shunt revisions. The results of this study suggest that surgical procedures within 30 days after shunt insertion and preshunt cardiac surgery are associated with a greater risk of shunt infection in children in whom these devices were inserted during the 1st year of life.

C-Reactive Protein in Prediction of Ventriculoperitoneal Shunt-Related Infection in High-Risk Patients

C-reactive protein (CRP) is an inflammatory marker believed to be of value in the early detection of meningitis. We evaluated its potential as a marker for prediction of shunt-related infection in high-risk subjects. We conducted a prospective pilot study in 26 ventriculoperitoneal shunt procedures; 18 of the patients were considered to be at high risk of infection at the time of shunt insertion. All patients were screened for other disease that could cause, an increase in CRP. The serum CRP medians were 3.90 mg/L in the whole sample and 5.36 mg/L in the high-risk participants. All four shunt infections occurred in the high-risk group (22.2% of the group), three (75%) of which were in patients with meningitis. The logistic regression model showed that CRP concentrations above the cut-off value of ≥ 7 mg/L were related to shunt infection (p=0.042). The receiving-operating characteristic curve revealed a cutoff point at ≥ 10.1 mg/L (sensitivity 0.75, 1 - specificity 0.18). The calculated area under the curve was 0.744. The sensitivity and specificity in the whole sample and high-risk group were not different (75% and 79%-80%, respectively). The positive post-test probability was 40% in the whole sample and 50% in the high-risk group. The negative post-test probability was 5% and 7%, respectively. Our data suggest that in a patient at high risk of shunt-related infection, the serum CRP concentration can be a valuable predictor of the risk of infection. Further studies in larger samples would be worthwhile.

Natural history of hydrocephalus in children with spinal open neural tube defect.

Background:The long-term prognosis of patients with Spinal Open Neural Tube Defect (SONTD)-associated hydrocephalus is not well known. This study was conducted to ascertain the incidence and natural history of hydrocephalus in patients with SONTD.Methods:All 82 patients with SONTD referred to Neurosurgery/Spina Bifida Clinics at King Khalid University Hospital, Riyadh, Saudi Arabia (January 1995 - July 2010) were studied and followed for a period of 1-16 years. Patients were divided into three groups: Group “A” with active hydrocephalus treated with ventriculoperitoneal shunt (VPS), or endoscopic third ventriculostomy (ETV); Group “B” with compensated hydrocephalus; and Group “C” with no hydrocephalus. Timing of shunt insertion, complications of treatment and status of hydrocephalus were analyzed.Results:The mean age of the 82 patients was 7.4 years (range 1-16 years). Group “A” included 59 (72%) patients, Group “B” 7 (8.5%) patients, and Group “C” 16 (19.5%) patients. Chiari malformation type II was found in 71 (86.6%) patients, 57 of whom (80%) were in Group “A” with active hydrocephalus. They were treated by VPS (51 patients) and ETV (8 patients). The shunts were revised or replaced in 10 (19.6%) patients due to obstruction or infection. Primary ETV failed in 3/8 patients, and treated by VPS. None of those in Groups “B” or “C” required treatment for hydrocephalus during the follow up.Conclusion:Hydrocephalus affects the majority of patients with SONTD who have Myelomeningocele (MMC) and CM II and requires close surveillance and prompt management. Children with SONTD should routinely undergo MRI examination of brain and craniocervical junction to clarify ventricular size, and the presence of CM II.

Comparison of simultaneous shunting to delayed shunting in infants with myelomeningocele in terms of shunt infection rate

Timing of shunt insertion in infants with myelomeningocele (MM) and hydrocephalus (HCP) has been debated. Many authors have suggested to perform the repair of MM and shunt insertion during same operation. However, there is also an opposite view. We analyzed retrospectively 166 patients who underwent MM Sac repair to evaluate whether there are difference between these two methods in terms of shunt infection rate. In the same session, V-P (ventriculoperitoneal) shunt placement was performed onto 65 infants within the first 48 hours of postnatal and 36 infants were operated 48 hours after birth. In separate sessions, repair of MM were performed onto 29 infants within the first 48 hours of postnatal and shunting was peformed 7 days after sac repair. 14 infants were performed MM sac repair 48 hours after birth, then shunt was applied 7 days after closure of MM. Shunt infection rate in concurrently operated groups was markedly high (12.3 % in early surgery, 33.3% in late surgery); in separatedly operated groups' shunt infection rate was lower (3.44% in early surgery, 14.29% in late surgery). We propose to perform V-P shunt placement and MM repair in separate sessions.

Breastfeeding: a potential protective factor against ventriculoperitoneal shunt infection in young infants

Previous studies have shown nutritional benefits of breastfeeding for a child's health, especially for protection against infection. Protective factors in human milk locally and systemically prevent infections in the gastrointestinal as well as upper and lower respiratory tracts. It remains unclear whether breastfeeding protects infants against ventriculoperitoneal (VP) shunt infection. A cohort study was conducted from December 2003 to December 2006 at Children's Hospital Medical Center in Tehran, Iran. A total of 127 infants with hydrocephalus who were treated using a VP shunt in the first 6 months of life were enrolled. Each infant's breastfeeding method was classified as either exclusively breastfed (EBF), combination feedings of breast milk and formula (CFBF), or exclusively formula-fed (EFF). Infants were followed up to determine the occurrence of shunt infection within 6 months after operation. Statistical analysis was performed using survival methods. Infants ranged in age from 4 to 170 days at the time of shunt insertion (mean 69.6 days), and 57% were males. Regarding the breastfeeding categories, 57.5% were EBF, 25.2% were CFBF, and 17.3% were EFF. During the follow-up, shunt infection occurred in 16 patients, within 15 to 173 days after shunt surgery (median 49 days). The 6-month risk of shunt infection was 8.5% (95% confidence interval [CI] 4-18%) in the EBF group, 16.5% (95% CI 7-35%) in the CFBF group, and 26.0% (95% CI 12-52%) in the EFF group. There was no statistically significant difference between these 3 groups (p=0.11). The trend test showed a significant trend between the extent of breastfeeding and the risk of shunt infection (p=0.035), which persisted even after adjustment for potential confounding variables (hazard ratio=2.01, 95% CI 1.01-4). This study supports the protective effect of breastfeeding against shunt infection during the first 6 months of life and the presence of a dose-response relationship, such that the higher the proportion of an infant's feeding that comes from human milk, the lower the incidence of shunt infection. Encouraging mothers of infants with VP shunts to breastfeed exclusively in the first 6 months of life is recommended.

Predicting slitlike ventricles in children on the basis of baseline characteristics at the time of shunt insertion

Slit ventricle syndrome (SVS) is a delayed complication of shunt insertion and occurs only in children with slitlike ventricles after shunt placement. Although SVS appears to be related to early shunt placement, its predisposing factors are largely unknown. Baseline data in 737 children who had received shunts were obtained from the databases of two previous clinical trials. Ventricular size before shunt placement and at the last routine follow up was measured using the frontooccipital horn ratio (FOHR). Ventricles with an FOHR less than or equal to 0.2 at follow up were classified as slitlike ventricles. A univariate analysis was performed on data obtained in children with more than 1 year of clinical and radiographic follow up to identify risk factors for developing slitlike ventricles. These results were entered into a multivariate analysis to identify independent predictors of slitlike ventricles. Two hundred forty-four children had more than 1 year of clinical and radiographic follow-up data. The 23 patients (9.4%) who developed slitlike ventricles had shunts inserted at a younger age (42 compared with 134 days, p = 0.09) and were more likely to have developed hydrocephalus secondary to infection (37.5%), head injury (25.0%), or aqueductal stenosis (22.2%). Slitlike ventricles were seen in 10.8% of patients with differential-pressure valves, 10.5% of patients with Delta valves, and 3.6% of patients with Orbis-Sigma valves (p = 0.007). Regression analysis supported the role of the valve type in developing slitlike ventricles. Age at shunt insertion and valve type appear to be the modifiable risk factors for developing slitlike ventricles. If the authors of subsequent studies can further validate these conclusions, slow-draining valves and delayed shunt insertion might be used to decrease the incidence of slitlike ventricles and SVS.

Serotonin and 5-hydroxy indole acetic acid in infantile hydrocephalus

The concentration of metabolites of neurohormones in cerebrospinal fluid (CSF) is an index of turnover of substances in brain parenchyma. The raised intracranial pressure in hydrocephalic children may cause alteration in the metabolism of neurohormones. Serotonin and its metabolite 5-HIAA have been studied extensively in CSF of patients with neuropsychiatric diseases. Hence we studied the neurohormones serotonin and its end product 5-hydroxy indole acetic acid (5-HIAA) in CSF of hydrocephalus infants before and after ventriculoperitoneal (VP) shunt. Ventricular CSF samples form 50 hydrocephalic infants were obtained serially at the time of shunt insertion, and then on day 8 and day 30 postoperatively by direct puncture from shunt chamber using 26G needles. Control CSF samples were taken from otherwise healthy children operated under spinal anesthesia. The samples were analyzed for serotonin and 5-HIAA by spectrofluorophotometric method. At the time of shunt insertion, serotonin was significantly decreased (P<0.05) while 5-HIAA was significantly increased (P<0.001) in hydrocephalic infants. On day 8 and day 30 values of serotonin and 5-HIAA approached the baseline values. In patients who developed VP shunt blockade there was again a rise in levels of 5-HIAA. However, no correlation could be established between the levels of serotonin, 5-HIAA and the duration of hydrocephalus and the type of hydrocephalus. Our study shows increased 5-HIAA concentration in CSF indicating increased turnover of serotonin to its metabolite due to pressure changes in hydrocephalus. Long-term follow-up is required to assess if they could be of prognostic significance as regards to long term attainment of brain functions in hydrocephalic children.

Shunt infection: is there a near-miss scenario?

The aim of this study was to establish whether microbiological contamination at the time of shunt insertion can be detected and used to predict the likelihood of subsequent shunt infection. A prospective study of pediatric patients undergoing primary shunt insertion was undertaken. Following the protocol devised for this study, three swab samples were collected from the surgical wounds during each procedure. These samples were incubated and subcultured, and the isolates were identified and stored. In patients who subsequently presented with clinical evidence of shunt infection, cerebrospinal fluid (CSF) was analyzed using microscopy, tissue cultures, and sensitivity testing. The organisms isolated at the time of shunt insertion and those responsible for subsequent shunt infection were then compared. The study population consisted of 107 pediatric patients. Because one patient underwent placement of an additional contralateral shunt system, there were 108 total shunt insertions yielding 325 swab samples. Organisms were identified in cultures of 50 swab samples (15%) obtained in 40 patients (37%). In seven of these 40 patients (17.5%) a CSF infection subsequently developed. In only one patient was the infectious organism the same as that isolated from the swab specimens. In an additional six patients (8.8%) a CSF infection occurred despite the lack of growth in the cultures from intraoperative swab samples. The organisms responsible for shunt infection were rarely detected in the operative wound at the time of shunt insertion, leading the authors to conclude that the vulnerable period for bacterial colonization of shunts may not be restricted to the operative procedure as is commonly believed, but may extend throughout the postoperative period of wound healing. These findings have implications not only for a better understanding of the cause of shunt infections but also for the development of strategies to prevent them.

Bispectral Index Profile During Carotid Cross Clamping

This study aimed at investigating the Bispectral Index (BIS) profile during carotid cross clamping (CXC). The study involved a pilot group of 10 patients undergoing routine carotid endarterectomy with shunt insertion under total intravenous anesthesia, and a study group of 26 additional patients. In all patients, rates of propofol and remifentanil providing a steady-state level of hypnosis (BIS: 40-60) were maintained constant throughout a recording period ranging from 3 minutes before CXC to shunt insertion. BIS was recorded throughout this period and the internal carotid backflow observed at the time of shunt insertion was graded as good, moderate, or poor. In addition, A-Line Autoregressive Index (AAI) and processed electroencephalogram (EEG) parameters were recorded in patients of the study group. All parameters were averaged over 1 minute before CXC, at CXC, 1, 2, and 3 minutes after CXC, and at shunt insertion. Statistical analysis was performed using chi2, Friedman, and Spearman correlation tests. For technical reasons, reliable AAI, BIS monitor-derived, and other processed EEG data were obtained in 24, 25, and 18 patients of the study group, respectively. During the first 3 minutes after CXC, BIS increased over 60 [68.8 (6.1)] in 47%, decreased below 40 [34.9 (4.4)] in 25%, and remained in the 40 to 60 range in 28% of all recruited patients. A BIS increase was more frequently observed in patients with moderate or poor than in those with good internal carotid backflow (78, 67, and 29%, respectively). It was significantly correlated to an increase in AAI and EEG amplitude, a decrease in EEG suppression ratio, and a shorter time between induction of anesthesia and CXC. A BIS decrease was significantly correlated to an increase in suppression ratio and a longer time between induction and CXC. In conclusion, during CXC under a constant level of intravenous anesthesia, BIS may increase, decrease, or remain unchanged. The paradoxical BIS increase could be related to borderline ischemia, a change in brain anesthetic agent concentration, or a change in the nociceptive-antinociceptive balance associated with a CXC-elicited painful stimulation. Caution should be used when interpreting BIS value during CXC.

Risk factors for pediatric ventriculoperitoneal shunt infection and predictors of infectious pathogens.

Identification of risk factors for shunt infection and predictors of infectious pathogens may improve current methods to prevent and treat shunt infections. We reviewed data on 820 consecutive ventriculoperitoneal (VP) shunt placement procedures in 442 pediatric patients at our institution during 1992-1998. Ninety-two shunts (11%) developed infection a median of 19 days (interquartile range, 11-35 days) after insertion. Premature birth (relative risk [RR], 4.81; 95% confidence interval [CI], 2.19-10.87), previous shunt infection (RR, 3.83; 95% CI, 2.40-6.13), and intraoperative use of the neuroendoscope (RR, 1.58; 95% CI, 1.01-2.50) were independent risk factors for shunt infection. The bacterial organisms early after shunt surgery (<14 days) were the same as those late after shunt surgery (>14 days). As determined by an analysis of the 92 infected shunts, hospital stay of >3 days at the time of shunt insertion (odds ratio [OR], 5.27; 95% CI, 1.15-25.3) and prior Staphylococcus aureus shunt infection (OR, 5.91; 95% CI, 1.35-25.9) independently increased the odds that S. aureus was the causal pathogen.

The long-term outcome in children with late-onset aqueductal stenosis resulting from benign intrinsic tectal tumors

Benign intrinsic tumors arising in the dorsal midbrain have long been recognized as a potential cause of late-onset aqueductal stenosis. Where histopathological studies of such lesions have been performed, the majority have been reported to be low-grade gliomas. Because these tumors often present with a paucity of neurological findings and a characteristic radiographic appearance and because there has been substantial uncertainty regarding their potential for long-term progression, the authors have routinely deferred biopsy and/or radiotherapy for these lesions until there has been clear-cut evidence of disease progression. Herein, the authors report their experience with 16 children manifesting this syndrome who were treated between 1979 and 1992. The patients ranged in age from 6 months to 14 years at presentation (median 9.75 years). In general, symptoms of increased intracranial pressure developed insidiously; three of the older children had exhibited profound macrocephaly since infancy, which predated the onset of other symptoms of hydrocephalus by several years. Only one of the 16 children showed evidence of brain-stem dysfunction at presentation, a partial Parinaud's syndrome that resolved following placement of a ventriculoperitoneal shunt. In 12 patients, the tumor was detected by magnetic resonance (MR) imaging at initial evaluation as a bulbous enlargement of the tectal plate. In four patients who presented before the advent of MR imaging, initial computerized tomography (CT) scans failed to delineate the tectal lesion convincingly; however, subsequent MR studies clearly demonstrated the presence of an intrinsic tectal mass. All 16 patients underwent cerebrospinal fluid diversion initially, with conservative management of the tectal lesion and close long-term follow-up monitoring. Four children ultimately demonstrated clinical signs of progressive tumor growth with the insidious onset of partial or complete Parinaud's syndrome, despite the presence of a functioning shunt. The median interval to symptom progression was 7.8 years from the time of shunt insertion and 11.5 years from the onset of initial symptoms and signs of hydrocephalus. Follow-up CT and MR studies demonstrated obvious tumor enlargement in three of the four patients who then underwent stereotactic or open biopsy. The histological diagnosis in these three was benign mixed glioma, anaplastic astrocytoma, and low-grade astrocytoma. All four patients with clinical evidence of disease progression were treated with conventional radiotherapy; the patient with an anaplastic astrocytoma also received focal stereotactic radiosurgery. These patients subsequently remained clinically stable, with three showing tumor regression and one showing stable disease on serial MR studies (median follow-up period from tumor progression, 4.25 years).(ABSTRACT TRUNCATED AT 400 WORDS)