Neurosurgery Blog

Acta Neurochir (2010) 152:989–995. DOI 10.1007/s00701-010-0605-x

Purpose: In patients with idiopathic normal pressure hydrocephalus (iNPH) and ventriculomegaly, examine whether there is a gradient in pulsatile intracranial pressure (ICP) from within the cerebrospinal fluid (CSF) of cerebral ventricles (ICPIV) to the subdural (ICPSD) compartment. We hypothesized that pulsatile ICP is higher within the ventricular CSF.

Methods The material includes 10 consecutive iNPH patients undergoing diagnostic ICP monitoring as part of pre-operative work-up. Eight patients had simultaneous ICPIV and ICPSD signals, and two patients had simultaneous signals from the lateral ventricle (ICPIV) and the brain parenchyma (ICPPAR). Intracranial pulsatility was characterized by the wave amplitude, rise time, and rise time coefficient; static ICP was characterized by mean ICP.

Results None of the patients demonstrated gradients in pulsatile ICP, that is, we found no evidence of higher pulsatile ICP within the CSF of the cerebral ventricles (ICPIV), as compared to either the subdural (ICPSD) compartment or within the brain parenchyma (ICPPAR). During ventricular infusion testing in one patient, the ventricular ICP (ICPIV) was artificially increased, but this increase in ICPIV produced no gradient in pulsatile ICP from the ventricular CSF (ICPIV) to the parenchyma (ICPPAR).

Conclusions: In this cohort of iNPH patients, we found no evidence of transmantle gradient in pulsatile ICP. The data gave no support to the hypothesis that pulsatile ICP is higher within the CSF of the cerebral ventricles (ICPIV) than within the subdural (ICPSD) compartment or the brain parenchyma (ICPPAR) in iNPH patients.

Childs Nerv Syst (2010) 26:791–796. DOI 10.1007/s00381-009-1061-x

The reported rate is up to 10% of shunt disconnection or fracture, either ventriculoperitoneal or subduroperitoneal. However, not all of shunt discontinuity is associated with shunt malfunction. We analyzed the discontinuity of the shunt system and related factors and tried to present a follow-up policy.

Methods This is a retrospective study involving 22 patients who presented with shunt disconnection because of malfunction or other reasons between January 2003 and October 2008. To evaluate shunt function, we performed a shuntogram, temporary ligation, or intraoperative exploration.

Results Nine (40.9%) of 22 patients had nonfunctioning shunts. The shunt system was removed in eight cases, and one patient refused surgical management. Of these 22 patients with disconnected shunts, 17 shunts placed in the occipital area were discontinued. The discontinuations were mostly fractured at neck (52%), not disconnected at connection site.

Conclusion Shunt disconnection has not been always represented a shunt malfunction. We thought many patients with disconnected shunt may be independent from shunt system, and it can be a good chance for patient to remove the shunt system

Journal of Neurosurgery, June 2010. DOI: 10.3171/2010.4.JNS10132

Neurosurgery 66:917-924, 2010 DOI: 10.1227/01.NEU.0000367801.35654.EC

Diffusion tensor imaging (DTI) parameters were investigated in patients with chronic idiopathic hydrocephalus to evaluate microstructural changes of brain tissue caused by chronic ventricular dilatation.

METHODS: Eleven patients fulfilling the criteria for possible or probable idiopathic normal pressure hydrocephalus and 10 healthy control subjects underwent MRI at 3 Tesla, including DTI with 12 gradient directions. Patients were scanned before lumbar cerebrospinal fluid (CSF) withdrawal tests. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between patients and controls were assessed using 2 different methods: manual definition of regions of interest and a fully automated method, TBSS (Tract-Based Spatial Statistics). DTI parameters were correlated with clinical findings.

RESULTS: Compared with the control group, patients with chronic idiopathic hydrocephalus had significantly higher MD values in both the periventricular corticospinal tract (CST) and the corpus callosum (CC), whereas FA values were significantly higher in the CST but lower in the CC. DTI parameters of the CST correlated with the severity of gait disturbances.

CONCLUSION:Microstructural changes in periventricular functionally relevant white matter structures (CSF, CC) in chronic idiopathic hydrocephalus can be visualized using DTI. Further studies should investigate the change of DTI parameters after CSF shunting and its relation to neurologic outcome.

Neurosurgery 66:904-909, 2010 DOI: 10.1227/01.NEU.0000368385.74625.96

This study investigated the outcome of early shunt placement in patients with poor-grade subarachnoid hemorrhage and the effect of intraventricular hemorrhage (IVH) and high proteinaceous cerebrospinal fluid (CSF) on subsequent shunt performance. METHODS:This study included 33 consecutive patients with initial Fisher grade (3/4) subarachnoid hemorrhage who had undergone conversion from external ventricular drainage (EVD) to a ventriculoperitoneal (VP) shunt and whose computed tomography scan showed IVH at the time of shunt placement. Early weaning from an EVD and conversion to a VP shunt was performed irrespective of IVH or high protein content in the CSF. RESULTS: The mean interval from EVD to VP shunt placement was 6.4 days. The mean volume of IVH was 9.44 mL, and the mean value of IVH/whole ventricle volume ratio (ie, percentage of blood suspension in the CSF) was 9.81%. The mean perioperative protein level in the CSF was 149 mg/dL. During the follow-up period, 2 patients (6.1%) required VP shunt placement, and no patients experienced complications of ventriculitis or shunt-related infection. CONCLUSION: Based on our data, earlier EVD weaning and shunt placement can effectively treat subarachnoid hemorrhage–induced hydrocephalus in patients with severe subarachnoid hemorrhage. This procedure resulted in no shunt-related infections and a 6.1% revision rate. There were fewer adverse effects of IVH and protein on shunt performance. Therefore, weaning from an EVD and conversion to a permanent VP shunt need not be delayed because of IVH or proteinaceous CSF.

J Neurosurg 112:832–839, 2010. (DOI: 10.3171/2009.7.JNS09550)

Ventriculomegaly is a common imaging finding in many types of conditions. It is difficult to determine whether it is related to true hydrocephalus or to an atrophic process by using only imaging procedures such as MR imaging after traumatic injury, stroke, or infectious disease. Diffusion tensor (DT) imaging can distinguish the compression characteristics of white matter, indicating that increased diffusion anisotropy may be related to white matter compression. In this preliminary study, the authors compared the DT imaging findings of ventriculomegaly with those of chronic hydrocephalus or atrophy to clarify the potential of diffusion anisotropy in the identification of hydrocephalus. Methods. Ten patients with chronic hydrocephalus, 8 patients with atrophy (defined by conventional devices and surgical outcome), and 14 healthy volunteers underwent DT imaging. Images were acquired before and after shunting or once in cases without shunting. The fractional anisotropy (FA) values at many points around the lateral ventricle were evaluated. Results. The FA patterns around the lateral ventricle in the chronic hydrocephalus and atrophy groups were different. Especially in the caudate nucleus, FA was increased in the chronic hydrocephalus group compared with the atrophy group. Furthermore, the FA values returned to normal levels after shunt placement. Conclusions. Assessment of the FA value of the caudate nucleus may be an important, less invasive method for distinguishing true hydrocephalus from ventriculomegaly. Further research in a large number of patients is needed to verify the diagnostic ability of this method.

Neurosurgery 66:465-474, 2010 DOI: 10.1227/01.NEU.0000365272.77634.6B

OBJECTIVE: To evaluate the reliability of the gravitation-assisted adjustable proGAV shunt system with a prospective multicenter study conducted in 10 German hospitals.

METHODS: Enrollment for this observational study began in April 2005 and concluded in February 2006. The protocol required re-examinations 3 and 6 months postoperatively and fixed the endpoint of follow-up at 12 months after implantation. Patients with different types of adult, juvenile, and pediatric hydrocephalus were included and 165 patients were enrolled; 9 died and 12 had incomplete follow-up.

RESULTS: Of the assessable 144 patients, 130 completed the protocol after 12 months, whereas 14 failed because of the need to explant the device, mainly because of infection. In 12 patients, components of the shunt, not the valve, were revised. In 65 of the 144 patients, there were 102 readjustments of the valve in 67 incidences because of underdrainage and in 35 because of overdrainage. In 1 case, readjustment was not possible. Determination of pressure level with the verification instrument was safe and corresponded to the required x-ray controls after adjustments. No unintended readjustments were noted.

CONCLUSION: The proGAV is a safe and reliable device.

Journal of Neurosurgery: Pediatrics. (DOI: 10.3171/2009.9.PEDS09196)

In Uganda, childhood hydrocephalus is common and difficult to treat. In some children, endoscopic third ventriculostomy (ETV) can be successful and avoid dependence on a shunt. This can be especially beneficial in Uganda, because of the high risk of infection and long-term failure associated with shunting. Therefore, the authors developed and validated a model to predict the chances of ETV success, taking into account the unique characteristics of a large sub-Saharan African population.

Methods. All children presenting with hydrocephalus at CURE Children’s Hospital of Uganda (CCHU) between 2001 and 2007 were offered ETV as first-line treatment and were prospectively followed up. A multivariable logistic regression model was built using ETV success at 6 months as the outcome. The model was derived on 70% of the sample (training set) and validated on the remaining 30% (validation set).

Results. Endoscopic third ventriculostomy was attempted in 1406 patients. Of these, 427 were lost to followup prior to 6 months. In the remaining 979 patients, the ETV was aborted in 281 due to poor anatomy/visibility and in 310 the ETV failed during the first 6 months. Therefore, a total of 388 of 979 (39.6% and [55.6% of completed ETVs]) procedures were successful at 6 months. The mean age at ETV was 12.6 months, and 57.8% of cases were postinfectious in origin. The authors’ logistic regression model contained the following significant variables: patient age at ETV, cause of hydrocephalus, and whether choroid plexus cauterization was performed. In the training set (676 patients) and validation set (303 patients), the model was able to accurately predict the probability of successful ETV (Hosmer-Lemeshow p value > 0.60 and C statistic > 0.70). The authors developed the simplified CCHU ETV Success Score that can be used in the field to predict the probability of ETV success.

Conclusions. The authors’ model will allow clinicians to accurately identify children with a good chance of successful outcome with ETV, taking into account the unique characteristics and circumstances of the Ugandan population.

J Neurosurg 112: 399–409, 2010. (DOI: 10.3171/2009.4.JNS081664)

Object. The test-retest method is commonly used in the management of patients with normal-pressure hydrocephalus (NPH). One of the most widely used techniques in the diagnosis of this condition is evaluation of the
patient’s response to CSF evacuation by lumbar puncture (a so-called tap test or spinal tap). However, interpretation of improved results in subsequent evaluations is controversial because higher scores could reflect a real change in specific abilities or could be simply the result of a learning effect.
Methods. To determine the effect of testing-retesting in patients with NPH, the authors analyzed changes documented on 5 neuropsychological tests (the Toulouse-Pieron, Trail Making Test A, Grooved Pegboard, Word Fluency, and Bingley Memory tests) and several motor ability scales (motor performance test, length of step, and walking speed tests) in a series of 32 patients with NPH who underwent the same battery on 4 consecutive days. The same tests were also applied in 30 healthy volunteers. In both groups, the authors used the generalized least-squares regression method with random effects to test for learning effects. To evaluate possible differences in response depending on the degree of cognitive impairment at baseline, the results were adjusted by using the Mini-Mental State Examination scores of patients and controls when these scores were significant in the model.
Results. In patients with NPH there were no statistically significant differences in any of the neuropsychological
or motor tests performed over the 4 consecutive days, except in the results of the Toulouse-Pieron test, which
were significantly improved on Day 3. In contrast, healthy volunteers had statistically significant improvement in the results of the Toulouse-Pieron test, Trail Making Test A, and Grooved Pegboard test but not in the remaining neuropsychological tests. Patients in the healthy volunteer group also exhibited statistically significant improvement in the motor performance test but not in step length or walking speed.
Conclusions. No learning effect was found in patients with NPH on any of the neuropsychological or motor tests. Clinical improvement after retesting in these patients reflects real changes, and this strategy can therefore be used in both the diagnosis and evaluation of surgical outcomes.

Neurosurgery 66:284-289, 2010 DOI: 10.1227/01.NEU.0000363405.12584.4D

BACKGROUND:The average hospital cost for shunt infection treatment is $50 000, making it the most financially costly implant-related infection in the United States. We set out to determine whether introduction of antibiotic-impregnated shunts (AISs) in our practice has decreased the incidence of shunt infection or decreased infection-related hospital costs at our institution.

METHODS: Clinical and hospital billing records of pediatric patients undergoing cerebrospinal fluid (CSF) shunt insertion at a single institution from April 2001 to December 2006 were retrospectively reviewed. Eighteen months before October 2002, all CSF shunts included standard, non-AIS catheters. During the 4 years after October 2002, all CSF shunts included AIS catheters. Patients were followed at least 18 months after surgery.

RESULTS: A total of 406 pediatric patients underwent 608 shunt placement procedures (400 AISs, 208 non-AISs). Of patients with non-AIS catheters, 25 (12%) experienced shunt infection, whereas only 13 patients (3.2%) with AIS catheters experienced shunt infection during follow-up (P < .001). The total hospital cost to treat 25 non-AIS shunt infections over the first 18 months was $1,234,928. The total hospital cost to treat 13 AIS shunt infections over the past 4 years was $606,328. The mean hospital cost per shunt infection was similar for infected AIS and non-AIS catheters ($46 640 vs. $49 397). However, the infection- related hospital cost per 100 patients shunted was markedly lower in the AIS cohort than in the non-AIS cohort ($151 582 vs. $593 715).

DISCUSSION: The introduction of AIS catheters in our institutional practice reduced the incidence of shunt infection and resulted in significant hospital cost savings. AIS systems are efficient and cost-effective instruments to prevent perioperative colonization of CSF shunt components.

Childs Nerv Syst (2010) 26:75–79.DOI 10.1007/s00381-009-0983-7

In the current literature, there are essentially no comparisons of quality of life (QOL) outcome after endoscopic third ventriculostomy (ETV) and shunt in childhood hydrocephalus. Our objective was to compare QOL in children with obstructive hydrocephalus, treated with either ETVor shunt. Methods A cross-sectional survey was conducted at SickKids, Toronto of children between ages five and 18 years, with obstructive hydrocephalus due to aqueductal obstruction and no other brain abnormalities. Measures of QOL were the Hydrocephalus Outcome Questionnaire and the Health Utilities Index Mark 3. A subset of patients was given the Wechsler Intelligence Scales for Children (WISC-IV). Results A total of 47 of 59 (80%) eligible patients participated (24 had ETV as primary treatment, 23 had shunt as primary treatment), with a mean age of 12.1 years (standard deviation 3.9) at assessment. The ETV group was older at initial surgery (p<0.001) and had larger ventricle size at last follow-up (p= 0.047). In all QOL measures, there were no significant differences between the ETV group and shunt group (all p≥ 0.09). Treatment failure, hydrocephalus complications, and the presence of a functioning ETV at assessment were not associated with QOL differences. Among the 11 children (six ETV, five shunt) who were given the WISC-IV, there were no significant differences between the scores of the ETV group and shunt group (all p≥0.11). Conclusions This is the first study to provide a meaningful comparison of QOL after ETV and shunt in children. These preliminary results suggest that there is no obvious difference in QOL after ETVand shunt.

J Neurosurg Pediatrics 5:4–16, 2010.(DOI: 10.3171/2008.7.17690)

This 25-year follow-up study was performed on 120 children with hypertensive hydrocephalus to evalu- ate the influence of the early prophylactic implantation of the Integra antisiphon device (ASD, Integra Neurosciences Ltd.) on the rate of proximal shunt obstructions and the frequency of symptomatic slit ventricle syndrome (SVS). The adaptability of the ASD to growth, proper positioning of the ASD as a necessity for its successful performance, and the 3 phases of SVS development are discussed.

Method. Since 1978, the ASD has consistently been implanted either at the time of primary shunt insertion (66 neonates, mean follow-up 11 years) or during revisions of preexisting shunts (54 children, mean follow-up 11.8 years). The complication rate among the 54 children before ASD implantation (mean follow-up 8.3 years) was com- pared with that among all 120 patients once an ASD had been inserted. Shunt complications were documented as ventricular catheter, distal catheter, and infectious complications.

Results. The study revealed a significant long-term reduction in ventricular catheter obstructions and hospitaliza- tions due to intermittent intracranial hypertension symptoms (symptomatic SVS) after both primary and secondary ASD implantation. Data in the study suggest that the high rate of ventricular catheter obstruction in pediatric shunt therapy is caused by hydrostatic suction induced by differential-pressure valve shunts during mobilization of the patient and that the development of a SVS can be traced back to this constant suction, which causes chronic CSF overdrainage and ventricular noncompliance. Recurrent ventricular catheter obstruction and SVS can be prevented by prophylactic supplementation of every shunt system with an ASD.

Conclusions. To inhibit chronic hydrostatic suction, to prevent overdrainage and proximal shunt obstruction, and to avoid SVS and thus improve the patient’s quality of life, the prophylactic implantation of an ASD in every pediatric hydrocephalus shunt is recommended.

Neurosurgery 66:80-91, 2010 DOI: 10.1227/01.NEU.0000363408.69856.B8

OBJECTIVE: To review our experience of managing idiopathic normal pressure hydrocephalus (iNPH) during the 6-year period from 2002 to 2007, when intracranial pressure (ICP) monitoring was part of the diagnostic workup.

METHODS: The review includes all iNPH patients undergoing diagnostic ICP monitoring during the years 2002 to 2007. Clinical grading was done prospectively using a normal pressure hydrocephalus (NPH) grading scale (scores from 3 to 15). The selection of patients for surgery was based on clinical symptoms, enlarged cerebral ventricles, and findings on ICP monitoring. The median follow-up time was 2 years (range, 0.3-6 years). Both static ICP and pulsatile ICP were analyzed.

RESULTS: A total of 214 patients underwent the diagnostic workup, of whom 131 went on to surgery. Although 1 patient died shortly after treatment, 103 of the 130 patients (79%) improved clinically. This improvement lasted throughout the observation period. The static ICP observed during ICP monitoring was a poor predictor of the response to surgery. In contrast, among 109 of 130 patients with increased ICP pulsatility (ie, ICP wave amplitude >4 mm Hg on average and >5 mm Hg in >10% of recording time), 101 (93%) were responders (ie, increase in the NPH score of >2). Correspondingly, only 2 of 21 (10%) without increased ICP pulsatility were responders. Superficial wound infection was the only complication of ICP monitoring and occurred in 4 (2%) patients.

CONCLUSION: Surgical results in iNPH were good with almost 80% of patients improving after treatment. The data indicate that improvement after surgery can be anticipated in 9 of 10 iNPH patients with abnormal ICP pulsatility, but in only 1 of 10 with normal ICP pulsatility. Diagnostic ICP monitoring had a low complication rate

Am J Neuroradiol 30:1898 –906.DOI 10.3174/ajnr.A1726

BACKGROUND AND PURPOSE: 3D-constructive interference in steady state (3D-CISS) sequence has been used to assess the CSF pathways. The aim of this study was to investigate the additive value of 3D-CISS compared with conventional sequences in the diagnosis of obstructive membranes in hydrocephalus.

MATERIALS AND METHODS: A total of 134 patients with hydrocephalus underwent MR imaging examination with a 3T unit consisting of turbo spin-echo, 3D-CISS, and cine phase-contrast (cine PC) sequences. 3D-CISS was used to assess obstructive membranes in CSF pathways compared with other sequences. Cine PC, follow-up imaging, and surgical findings were used to confirm obstructive membranes.

RESULTS: Comparing the number of noncommunicating cases by using the conventional and 3D-CISS images, we found 26 new cases (19.4%) of 134 cases that were previously misdiagnosed as communicating hydrocephalus by conventional images. 3D-CISS sequence identified obstructive membranes invisible in other sequences, which facilitated selection of neuroendoscopy in the treatment of 31 patients (23.1%) in total who would have been otherwise treated with shunt insertion. These patients included 26 newly diagnosed noncommunicating cases after demonstration of intraventricular and/or fourth ventricular outlet membranes and 5 cases of communicating hydrocephalus with obstructing cisternal membranes. There were obstructions of the foramina of Luschka in 22 of 26 newly found noncommunicating cases.

CONCLUSIONS: Conventional sequences are insensitive to obstructive membranes in CSF pathways, especially in the fourth ventricular exit foramina and the basal cisterns. 3D-CISS sequence, revealing these obstructive membranes, can alter patient treatment and prognosis.

Neurosurgery 65:1197–1201, 2009.DOI: 10.1227/01.NEU.0000356973.39913.0B

OBJECTIVE: Free-hand insertion of an external ventricular drain (EVD) is a common emergency neurosurgical procedure, mostly performed for critically ill patients. Although EVD complications have been studied thoroughly, the accuracy of EVD positioning has been audited only occasionally.

METHODS: Post-EVD insertion computed tomographic scans performed in our unit over a 2-year period were analyzed for EVD tip location and intracranial catheter length.

RESULTS: A total of 183 post-EVD insertion scans were reviewed. Of those, 73 EVD tips (39.9%) were in the ipsilateral frontal horn of the lateral ventricle (the desired tar- get); of those, 18 (25%) required EVD revision/reinsertion. Of the others, 35 (19.1%) were in the third ventricle, 33 (18%) in the body of the lateral ventricle, 19 (10.4%) in the sub- arachnoid space, 5 (2.7%) in the contralateral frontal horn, and 18 (9.8%) within the brain parenchyma. When the EVD tip was outside the desired target, 44 of the patients (40%) required EVD revision/reinsertion procedure (P = 0.0383).

CONCLUSION: Free-hand insertion of an EVD is an inaccurate procedure, and further studies are required to assess the accuracy and feasibility of the routine use of neuro- navigation, ultrasonography, or other guidance techniques and the possible implication of the decreasing revision rate, complications, and length of hospital stay.

Childs Nerv Syst. DOI 10.1007/s00381-009-1019-z

The outcome of endoscopic third ventriculostomy (ETV) is worse in children younger than 2 years old and especially in infants, and controversies still exist whether ETV might be superior to shunt placement in this age group. We retrospectively analyzed the data of 23 patients younger than 6 months of age treated with ETV and assessed its feasibility as a first choice of treatment for hydrocephalus.

Methods: Between 1994 and 2008 in our clinic, 23 patients younger than 6 months having presented with obstructive hydrocephalus were treated endoscopically. The etiology of hydrocephalus was congenital aqueduct stenosis in 11 patients, posthemorrhagic obstruction in six patients, myelomeningocele in two patients, postmeningitis in two patients, Chiari I malformation in one patients, and Dandy Walker variant in one patient. ETV was considered successful when no shunt operation was needed in the patient.

Results: ETV was successful in eight patients with regression of intracranial hypertension. In the remaining 15 patients ventriculoperitoneal shunt implantation was necessary. Total success rate in our group of patients was 34.8%. In patients younger than 3 months of age (n=12), success rate was 25.0%. In patients from 3 to 6 months of age (n=11), success rate was 45.5%. Complication included intraventricular hemorrhage in one patient, meningitis and cerebrospinal fluid leak in one patient, and meningitis in one patient.

Conclusions: Based on our experience, ETV could be the first method of choice for hydrocephalus in children younger than 6 months of age, especially in patients older than 3 months of age.

British Journal of Neurosurgery,23:5,521-523. DOI: 10.1080/02688690902980849

Endoscopic third ventriculostomy (ETV) is a well established treatment for selected cases of obstructive hydrocephalus. However, it does carry a significant rate of failure, which can be abrupt and life threatening. The present study analyses the benefits versus the risks of routine CSF reservoir insertion during ETV. Clinical data obtained from the medical records of patients from a single neurosurgical centre who underwent ETV between August 2002 and February 2007 were analysed retrospectively. A total of 34 records were available with follow-up ranging from 3–56 months (Median 26 months) and with patient age range between 6 months – 75 yrs (median 19 years). During this period, one neurosurgeon routinely placed reservoirs in all patients undergoing ETV (n1/434). In all instances of reservoir insertion, Ommaya reservoirs were used. The number of patients in which the reservoir was tapped for diagnostic and/or therapeutic reasons was quantified, and all complications resulting from reservoir placement recorded. ETV success was defined by a lack of subsequent need for cerebrospinal fluid diversion. In total 13 of 34 (38%) reservoirs inserted were tapped at a later date and there were no complications associated with their insertion. Tapping of reservoirs helped determine which patients required subsequent ventriculoperitoneal (VP) shunting. In at least one case reservoir tapping was carried out as an emergency and was a crucial intermediate intervention prior to further surgery. The overall success rate of ETV was 65% (95% CI, 49–81%) with four complications associated with ETV: short-term memory loss, psychosis, and two cases of post-operative seizures. These complications were not attributed to CSF reservoir insertion but the ETV procedure itself. The routine placement of CSF reservoir following ETV thus seems justified with respect to the observed benefits and lack of complications associated with its placement.

J Neurosurg 111:1029–1035, 2009. DOI: 10.3171/2008.9.JNS08881

Chronic shunt­dependent hydrocephalus is a recognized complication of aneurysmal subarachnoid hem­ orrhage. While its incidence and risk factors have been well described, the long­term 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 treat­ ment of a ruptured aneurysm in Ontario, Canada, between 1995 and 2005. The authors determined the incidence of shunt­dependent 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 multivari­ ate 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 loca­ tion in the posterior circulation and endovascular treatment of the initial ruptured aneurysm.

Conclusions. Shunt-dependent hydrocephalus affects a significant proportion of subarachnoid hemorrhage sur­ vivors, 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.

Neuroradiology DOI 10.1007/s00234-009-0610-z

We attempted to detect alterations in the cerebrospinal fluid (CSF) space in patients with idiopathic normal pressure hydrocephalus (iNPH) using voxel-based morphometry (VBM).

Methods. We obtained sagittal volume images of the entire head by three-dimensional T1-weighted magnetic resonance imaging and compared the regional distribution of CSF in 12 patients with iNPH, 14 patients with Alzheimer’s disease (AD), and 17 healthy individuals using VBM with automatically extracted CSF objects.

Results. VBM demonstrated significant widening at the lateral ventricles and Sylvian fissures and narrowing of the CSF space at the high convexity/midline areas in iNPH patients, compared to the AD patients and healthy controls (p<0.05, after correction with a false-discovery rate). In addition, the ratio of the CSF volume in the lateral ventricle/Sylvian fissure area to that in the high convexity/midline area in iNPH patients (3.9 ± 1.2) was remarkably greater than that in AD patients (1.2 ± 0.3) ANOVA, p < 0.001; post hoc Tukey’s test, p < 0.001); we could discriminate iNPH patients from those in the other two groups without any overlap, when using a cutoff level of 1.9.

Conclusion. VBM using CSF objects can be used to delineate the characteristic alteration of the CSF space in iNPH patients, which has been evaluated by visual interpretation.

J Neurosurg Pediatrics 4:389–393, 2009. (DOI: 10.3171/2009.4.PEDS09210)

In recent years CSF shunt catheters impregnated with rifampicin and clindamycin have been introduced to the United Kingdom (UK) market. These catheters have been shown to be effective in vitro against cultures of Staphylococcus epidermidis. The authors used data collected by the UK Shunt Registry to assess the efficacy of antibiotic-impregnated catheters (AICs) against shunt infection by using a matched-pair study design.

Methods. The UK Shunt Registry contains data on nearly 33,000 CSF shunt-related procedures. The authors identified 1139 procedures in which impregnated catheters had been used, and accurate information was known about diagnosis, number of revisions, sex, and age in these cases. The database was ordered chronologically and searched forward and backward for cases with these same characteristics but involving conventional catheters. Matches were found for 994 procedures.

Results. Among the 994 procedures in which AICs had been used, 30 shunts were subsequently revised because of shunt infection. Among the 994 controls, 47 were subsequently revised for infection (p = 0.048, chi-square test).

Conclusions. The UK Shunt Registry does not collect data on causative organisms, and the surgeon is relied on entirely for the diagnosis of infection. However, with the large number of matched pairs evaluated, the authors attempted to reduce bias to a minimum. Their data suggest that AICs have the potential to significantly reduce shunt infections.