Category: hydrocephalus

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Shunt surgery in patients with hydrocephalus and white matter changes

J Neurosurg 114:1432–1438, 2011. DOI: 10.3171/2010.11.JNS10967

Patients with idiopathic normal pressure hydrocephalus (iNPH) often present with impaired gait and cognition together with ventricular enlargement and normal intracranial pressure. Many have vascular risk factors as well as periventricular and deep white matter changes on MR imaging. Abnormal CSF dynamics, that is, high resistance to outflow or improvement after CSF drainage, indicate good effects of shunt surgery. The authors examined whether the worst-case iNPH patients with extensive vascular white matter disease and normal CSF dynamics would benefit from shunt surgery. These patients also fulfilled the criteria for Binswanger disease. Therefore, a randomized controlled double-blind study was performed.

Methods. Fourteen consecutive patients fulfilling the above criteria were randomized to receive either open or closed shunts. At 3 months after surgery, the patients with initially ligated shunts had their shunts opened. Clinical evaluation consisting of 7 quantitative psychometric and 6 continuous gait tests was performed preoperatively and 3 and 6 months after surgery.

Results. Patients randomized to receive open shunts had improved motor (30% increase) and psychometric (23% increase) scores 3 months after shunt placement. There were no significant changes between the 3- and 6-month follow- up in these same patients. Conversely, those with initially ligated shunts were unchanged during the first 3-month period, although they improved in both motor (28%) and cognitive (18%) functions following removal of the ligature.

Conclusions. Patients with enlarged ventricles, hydrocephalic symptoms, and extensive vascular white matter changes benefit from shunt surgery.

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Hydrocephalus associated with vestibular schwannomas: management options and factors predicting the outcome

J Neurosurg 114:1209–1215, 2011. DOI: 10.3171/2010.10.JNS1029

The current, generally accepted optimal management for hydrocephalus related to vestibular schwannomas (VSs) is primary tumor removal, with further treatment reserved only for patients who remain symptomatic. Previous studies have shown, however, that this management can lead to an increase in surgery-related complications. In this study, the authors evaluated their experience with the treatment of such patients, with the aim of identifying the following: 1) the parameters correlating to the need for specific hydrocephalus treatment following VS surgery; and 2) patients at risk for developing hydrocephalus-related complications.

Methods. This was a retrospective study of a 400-patient series. The complication rates and outcomes following primary hydrocephalus treatment versus primary VS removal were compared. Patients undergoing primary tumor removal were further subdivided on the basis of the need for subsequent hydrocephalus treatment. The 3 categories of parameters tested for correlation with the need for such subsequent treatment as well as with heightened risk for developing complications were patient-, tumor-, and hydrocephalus-related.

Results. Of the entire series, 53 patients presented with hydrocephalus. Forty-eight of 53 patients underwent primary VS surgery, of whom 42 (87.5%) did not require additional hydrocephalus treatment. Of the 6 patients who did require additional hydrocephalus treatment, only 3 ultimately required a VP shunt. Factors correlating to the need of hydrocephalus treatment after VS removal were large tumor size, irregular tumor surface, and severe preoperative hydrocephalus. Patients with a longer symptom duration prior to surgery, those with polycyclic tumors, or with inhomogeneous VS, were at heightened risk for the development of CSF leaks. The general and functional outcome of surgery showed no correlation to the presence of preoperative hydrocephalus.

Conclusions. Primary tumor removal is the optimum management of disease in patients with VS with associated hydrocephalus; it leads to resolution of the hydrocephalus in the majority of cases, and the outcome is similar to that of patients without hydrocephalus. Certain factors may aid in identifying patients at risk for developing persistent hydrocephalus as well as those at risk for CSF leaks

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Morbidity of Ventricular Cerebrospinal Fluid Shunt Surgery in Adults: An 8-Year Study

Neurosurgery 68:985–995, 2011 DOI: 10.1227/NEU.0b013e318208f36

Cerebrospinal fluid (CSF) shunt procedures have dramatically reduced the morbidity and mortality rates associated with hydrocephalus. However, despite improvements in materials, devices, and surgical techniques, shunt failure and complications remain common and may require multiple surgical procedures.

OBJECTIVE: To evaluate CSF shunt complication incidence and factors that may be associated with increased shunt dysfunction and infection rates in adults.

METHODS: From January 1999 to December 2006, we conducted a prospective surveillance program for all neurosurgical procedures including reoperations and infections. Patients undergoing CSF shunt placement were retrospectively identified among patients labeled in the database as having a shunt as a primary or secondary intervention. Revisions of shunts implanted in another hospital or before the study period were excluded, as well as lumbo- or cyst-peritoneal shunts. Shunt complications were classified as mechanical dysfunction or infection. Follow-up was at least 2 years. Potential risk factors were evaluated using log-rank tests and stepwise Cox regression models.

RESULTS: During the 8-year surveillance period, a total of 14 275 patients underwent neurosurgical procedures, including 839 who underwent shunt placement. One hundred nineteen patients were excluded, leaving 720 study patients. Mechanical dysfunction occurred in 124 patients (17.2%) and shunt infection in 44 patients (6.1%). These 168 patients required 375 reoperations. Risk factors for mechanical dysfunction were atrial shunt, greater number of previous external ventriculostomies, and male sex; risk factors for shunt infection were previous CSF leak, previous revisions for dysfunction, surgical incision after 10 AM, and longer operating time.

CONCLUSION: Shunt surgery still carries a high morbidity rate, with a mean of 2.2 reoperations per patient in 23.3% of patients. Our risk-factor data suggest methods for decreasing shunt-related morbidity, including peritoneal routing whenever possible and special attention to preventing CSF leaks after craniotomy or external ventriculostomy.

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Pineal region tumors: an optimal approach for simultaneous endoscopic third ventriculostomy and biopsy

Neurosurg Focus 30 (4):E3, 2011. DOI: 10.3171/2011.2.FOCUS10301

Simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is a widely accepted therapeutic and diagnostic procedure for patients with noncommunicating hydrocephalus secondary to a pineal region tumor. Multiple approaches have been advocated, including the use of a steerable fiberoptic or rigid lens endoscope via 1 or 2 trajectories. However, the optimal approach has not been established based on the individual anatomical characteristics of the patient.

 Methods. A retrospective review of patients undergoing simultaneous ETV and tumor biopsy was undertaken. Preoperative MR images were examined to measure the width of the anterior third ventricle and maximal diameters of the tumor, Monro foramen (right), and massa intermedia. The distances between the tumor and massa intermedia, tumor and anterior commissure, midbrain and massa intermedia, and the dorsum sella and anterior commissure were also recorded. Single and dual trajectory approaches were compared using paired t-tests for each parameter.

Results. Over an 8-year interval, 15 patients underwent simultaneous ETV and tumor management. These patients ranged from 6 to 71 years of age (mean 36.7 years); 5 were younger than 18 years of age. Seven were treated using a dual trajectory approach, and 8 were treated using a single trajectory approach. All cases were completed without complications or the need for an additional CSF diversionary procedure within 6 months. The diagnostic yield at biopsy was 86.7%. There were no statistically significant differences between the single and dual trajectory groups for the measured parameters. However, the dual trajectory group demonstrated a larger anterior third ventricular diameter (1.43 vs 1.21 cm, p = 0.29). The single trajectory group trended toward a smaller tumor– anterior commissure interval (2.23 vs 2.51 cm, p = 0.24) and a larger dorsum sella–anterior commissure distance (1.67 vs 1.49 cm, p = 0.28).

Conclusions. These data confirm the safety and diagnostic efficacy of simultaneous ETV and biopsy for tumors of the pineal region. Although no statistically significant differences were seen in the authors’ recorded measurements, several trends suggest a role for a tailored approach to selecting a single or dual trajectory approach when using a rigid endoscope

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Prevention of Ventriculostomy-Related Infections With Prophylactic Antibiotics and Antibiotic- Coated External Ventricular Drains: A Systematic Review

Neurosurgery 68:996–1005, 2011 DOI: 10.1227/NEU.0b013e3182096d84

Ventriculostomy-related infection (VRI) is a severe complication of external ventricular drain use, occurring in 5% to 23% of patients. Preventive measures for VRI include prolonged prophylactic systemic antibiotics (PSAs) and an antibioticcoated external ventricular drains (ac-EVDs).

OBJECTIVE: We performed a systematic review of all studies evaluating PSAs and ac-EVD for VRI prevention through July 2010.

METHODS: Two reviewers independently assessed eligibility and evaluated study quality based on pre-established criteria. Observational studies and randomized clinical trials (RCTs) that fulfilled inclusion criteria were included in the meta-analysis.

RESULTS: Three RCTs and 7 observational studies met our inclusion criteria and were included in the analysis. The type of antibiotics and VRI definitions varied among these studies. Pooled analysis showed a protective effect of PSAs and ac-EVDs for VRI (risk ratio: 0.32; 95% CI: 0.18-0.56). Results showed moderate heterogeneity (I2 = 53%) explained by the difference in quality among the studies and the inclusion of 1 large positive cohort study. The effect of PSAs and ac-EVDs was unrelated to the type of study (RCT or observational, P for interaction = .55), the route of antibiotic administration (PSAs or ac-EVDs, P = .13), or the quality of the studies (suboptimal vs good/excellent, P = .55).

CONCLUSION: RCTs and observational-derived evidence support the use of PSAs throughout the duration of external ventricular drainage; similarly, the use of ac-EVDs to prevent VRI seems to be beneficial. Available data are heterogeneous and of suboptimal quality. Further research is needed to confirm the findings of this meta-analysis. There are not sufficient data to compare the protective effect of ac-EVDs and PSAs.

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Evans’ Index Revisited: The Need for an Alternative in Normal Pressure Hydrocephalus

Neurosurgery 68:939–944, 2011 DOI: 10.1227/NEU.0b013e318208f5e0

The international guidelines for the diagnosis of normal pressure hydrocephalus (NPH) define ventricular enlargement as Evans’ index greater than 0.3.

OBJECTIVE: To establish whether there is a correlation between Evans’ index and ventricular volume (VV) in NPH and whether choosing different planes for the measurements could produce significantly different results.

METHODS: Pre–shunt insertion, thin-section CT scans of the brains of 10 patients with shunt-responsive NPH were reviewed retrospectively, measuring Evans’ index, frontal horn index, VV, and total intracranial volume (ICV). The ventricular/intracranial volume index (VV/ICV) was calculated. Correlation between each of the linear indices and VV and VV/ICV was done.

RESULTS: Significant differences were found in the index values calculated at different planes. The frontal horn index at a plane 16 mm parallel to the anterior commissure– posterior commissure (AC-PC) plane showed best correlation with VV and VV/ICV (r: 0.658 and 0.587, respectively). Evans’ index, also obtained at a plane 16 mm parallel to the AC-PC plane, showed best correlation with VV and VV/ICV (r: 0.619 and 0.498, respectively).

CONCLUSION: Evans’ index value can vary significantly in a patient with NPH, depending on the level of the brain CT scan image at which the frontal horns and maximal inner skull diameters are measured. Evans’ index is not an ideal method for estimating the VV in NPH patients. Volumetric measurements represent the logical accurate estimate of true ventricular size as well as the size of the other intracranial compartments.

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A Novel Method for Cerebrospinal Fluid Diversion: A Cadaveric and Animal Study

Neurosurgery 68:491–495, 2011 DOI: 10.1227/NEU.0b013e3181ffa21c

Cerebrospinal fluid (CSF) diversionary methods are fraught with complications (eg, infection, obstruction, and CSF malabsorption at the distal site).

INTRODUCTION: The authors investigated the sternum, specifically the manubrium, as a potential CSF receptacle for patients with hydrocephalus.

METHODS: Five fresh adult human cadavers had the manubrium cannulated in a suprasternal location. Tap water was infused via a metal trocar for approximately 60 minutes. Additionally, morphometric examination of the manubrium from 40 adult human skeletons was performed. Next, 4 anesthetized rhesus monkeys underwent cannulation of the manubrium: 2 were infused with 50 mL of saline over approximately 1 hour, and 2 were infused by gravity drip of saline over 24 hours. Finally, 2 adult pigs underwent long-term ventriculosternal tube placement with analysis for function and potential development of osteomyelitis.

RESULTS: Thirty liters of water were injected into all cadaveric specimens without overflow or noticeable edema. No fluid accumulation was identified. The manubrium had a mean length, width, and thickness of 5.1 cm, 5.0 cm, and 1 cm, respectively. The animals that underwent infusion of 50 mL of saline and the animals that underwent gravity drip tolerated the procedure without vital sign changes or evidence of saline leakage into the pleural cavity. The 2 pigs did not show any vital sign changes, and, 2 weeks post procedure, they had no findings of osteomyelitis.

CONCLUSION: Based on our studies, the manubrium of the sternum appears to be an ideal location for the placement of the distal end of a CSF diversionary shunt when other anatomic receptacles are not an option. In vivo human studies are now required to verify our findings.

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Variability among pediatric neurosurgeons in the threshold for ventricular shunting in asymptomatic children with hydrocephalus

J Neurosurg Pediatrics 7:000–000, 2011.DOI: 10.3171/2010.11.PEDS10275

The thresholds for shunting CSF in children with asymptomatic hydrocephalus are unclear; there are neither guidelines nor sufficient research to determine what degree of hydrocephalus should be treated. The authors hypothesize that 1) pediatric neurosurgeons currently have high thresholds for recommending treatment for these children, but 2) there is significant variability among these treatment thresholds.

Methods. The authors surveyed attendees of the Joint Pediatric Neurosurgery Section meeting in Spokane, Washington, in December 2008, regarding their treatment thresholds for 22 clinical scenarios. Each participant was provided an illustration of 5 imaging studies (3 slices each) showing progressively larger ventricles. For each scenario, respondents were asked to indicate the minimum ventricular size they would treat, if any. Responses were quantified from 1 to 6 from smaller to larger, with 6 being no treatment, and a mean theoretical treated ventricular size (MTTVS) was calculated for each scenario.

Results. Respondents were relatively conservative in recommending treatment, with MTTVSs of 3.7–6.0; in 13 scenarios, the MTTVS was greater than 5.0 (larger than the largest presented ventricular size). For scenarios in which a mean frontooccipital ratio could be calculated, the value ranged from 0.55 to 0.67 (moderate to severe hydrocephalus). Although there were clear majority responses for each scenario, there was also significant variability. There were no patterns of association with the respondent’s age, training, board certification, or type or location of practice.

Conclusions. This study demonstrates that pediatric neurosurgeons’ thresholds for treating asymptomatic children with hydrocephalus are generally high, but there is also significant variability.

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

Neurosurgery 68:198–205, 2011 DOI: 10.1227/NEU.0b013e3181fe2db6

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 k = 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, k = 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 noninvasive flow measurement can be assessed.

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Postshunt Cognitive and Functional Improvement in Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 68:416–419, 2011 DOI: 10.1227/NEU.0b013e3181ff9d01

Improvement in gait after shunt placement has been well documented in idiopathic normal pressure hydrocephalus (iNPH); however, controversy remains regarding the extent and pattern of postsurgical cognitive changes. Conflicting findings may be explained by variability in both test selection and follow-up intervals across studies. Furthermore, most investigations lack a control group, making it difficult to disentangle practice effects from a true treatment effect.

OBJECTIVE: To examine postshunt changes in a sample of well-characterized iNPH participants compared with a group of age- and education-matched healthy control subjects.

METHODS: We identified 12 participants with iNPH undergoing shunt placement and 9 control participants. All participants were evaluated with comprehensive neuropsychological testing and standardized gait assessment at baseline and were followed up for 6 months.

RESULTS: Repeated-measures analysis of variance revealed a significant group- (iNPH and control) by-time (baseline and 6 months) interaction for Trailmaking Test B: (P< .003) and Symbol Digit Modalities (P< .02), with greater improvement in iNPH participants relative to control subjects. In addition, the iNPH group showed greater improvement in gait (P< .001) and caregivers reported improved activities of daily living (P , .01) and reduced caregiver distress (P< .01).

CONCLUSION: This study demonstrates improvements in mental tracking speed and sustained attention 6 months after shunt placement in iNPH. The present investigation is the first study to use a controlled design to show that cognitive improvement in iNPH is independent of practice effects. Furthermore, these findings indicate functional and quality-of-life improvements for both the shunt responder and their caregiver.

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Risk Factors for Conversion to Permanent Ventricular Shunt in Patients Receiving Therapeutic Ventriculostomy for Traumatic Brain Injury

Neurosurgery 68:85–88, 2011 DOI: 10.1227/NEU.0b013e3181fd85f4

Intracranial pressure is routinely monitored in patients with severe traumatic brain injury (TBI). Patients with TBI sometimes develop hydrocephalus, requiring permanent cerebrospinal fluid (CSF) diversion. OBJECTIVE: To quantify the need for permanent CSF diversion in patients with TBI. METHODS: Patients who received a ventriculostomy after TBI between June 2007 and July 2008 were identified, and their medical records were abstracted to a database. RESULTS: Sixteen of 71 patients (22.5%) receiving a ventriculostomy required a ventriculoperitoneal or ventriculoatrial shunt before discharge from the hospital. The average number of days between ventriculostomy and shunt was 18.3. Characteristics that predispose these patients to require permanent CSF diversion include the need for craniotomy within 48 hours of admission (odds ratio, 5.20; 95% confidence interval, 1.48-18.35) and history of culture-positive CSF (odds ratio, 5.52; 95% confidence interval, 1.19-25.52). Length of stay was increased in patients receiving permanent CSF diversion (average length of stay, 61 vs 31 days; P = .04). Patient discharge disposition was similar between shunted and nonshunted patients. CONCLUSION: In this retrospective study, 22% of TBI patients who required a ventriculostomy eventually needed permanent CSF diversion. Patients with TBI should be assessed for the need for permanent CSF diversion before discharge from the hospital. Care must be taken to prevent ventriculitis. Future studies are needed to evaluate more thoroughly the risk factors for the need for permanent CSF diversion in this patient population.

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Intraventricular migration of the bone dust. Is a second operation for removal necessary?

Childs Nerv Syst. DOI 10.1007/s00381-010-1339-z

As the number of endoscopic third ventriculostomy (E3V) operations increase, new rare complications are encountered. In this article, a complication caused by bone particles that migrated into the third ventricle will be described. Additionally, the methods of avoidance as well as the necessity of a new approach will be discussed.

Methods After the video images of the first and second operations of a patient who was subjected to E3V twice were compared, it was discovered that one of the bone particles within the ventricle had occluded the ostium after the second operation. Most of the bones were removed and their pathological investigations were performed.

Results Video images of the patient, surgical observations of the second operation, emergence of the time of dysfunction, and other similar cases in the literature were assessed, and it was concluded that the bones that localized intraventricularly were living tissues.

Discussion Abandoning usage of bone dust for sealing burr holes is a solution to avoid this complication. In addition, it should be kept in mind that intraventricular bone particles might grow and lead to obstructions. If such particles are detected, removal of the bones in certain locations before formation of neovascularization can be an option.

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Investigating shunt function using continuous intracranial pressure monitoring in adults: single center experience

J Neurosurg 113:1326–1330, 2010. (DOI: 10.3171/2010.8.JNS1067)

Managing symptomatic ventriculoperitoneal shunts with no clear evidence of shunt malfunction either clinically or radiologically can be a difficult task. The aim of this study was to assess intracranial pressure (ICP) monitoring as a method of investigating shunt function.

Methods. The authors performed a retrospective analysis of 38 continuous ICP monitoring procedures done in patients with ventriculoperitoneal shunts and suspected shunt malfunction.

Results. Thirty-eight procedures were performed in 31 patients between January 2005 and October 2008. Sixteen recordings were normal, 6 revealed overdrainage or low pressure, 11 indicated underdrainage or high pressure, and 5 showed variable shunt function. Based on the findings after 20 procedures (53%), patients were treated conservatively: 4 by readjusting the valve setting and 16 by referral to the headache neurologist for medical treatment. Forty-five percent of the conservatively treated patients improved. Surgical exploration was undertaken following 18 procedures (47%); 72% of the surgically treated patients improved.

Conclusions. Continuous ICP monitoring using an intraparenchymal probe is a safe and effective method of investigating adult hydrocephalus.

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A Multicenter Multinational Registry for Assessing Ventriculoperitoneal Shunt Infections for Hydrocephalus

Neurosurgery 67:1303–1310, 2010 DOI: 10.1227/NEU.0b013e3181f07e76

Reported infection rates after ventriculoperitoneal shunt surgery vary from 1 to 25%. Antibiotic-impregnated (AI) catheters may reduce shunt infection rates, but this is uncertain.

OBJECTIVE: To establish a prospective shunt registry to evaluate short-term (3-month) infection rates associated with ventriculoperitoneal shunts and standard or AI catheters during surgical treatment of hydrocephalus.

METHODS: A prospective, multicenter, noncontrolled, open-label registry investigated patients with de novo catheter implantation or catheter replacement of an existing ventriculoperitoneal shunt. The primary outcome was shunt infection.

RESULTS: A total of 440 patients were entered into the registry at 10 sites: 3 in North America, 2 in Singapore, 4 in China and 1 in India. Seven patients were excluded. Of the 433 remaining patients, 314 had new shunts and 119 were revisions. Shunt infections occurred in 14 of 433 patients (3.2%) overall and in 2 of 37 infants (5.2%) younger than 1 year. AI catheters were used in 46 of 433 patients at 7 centers. The shunt infection rate was 0 of 46 for shunts with AI catheters and 14 of 387 (3.6%) without AI catheters. Infection rates were similar with AI catheters, adjusting for age and catheter type.

CONCLUSION: The overall shunt infection rate was lower than in previous multicentered studies. The low infection rate and low rate of AI catheter use precludes any meaningful statement regarding the value of AI catheters in reducing the infection rate. Consideration should be given to performing a well designed, adequately powered, prospective randomized controlled trial to determine whether AI catheters reduce shunt infection rates.

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Predictors of long-term shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage

J Neurosurg 113:774–780, 2010. DOI: 10.3171/2010.2.JNS09376

The purpose of this study was to identify predictors of shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH).

Methods. The authors evaluated the incidence of shunt-dependent hydrocephalus in a consecutive cohort of 580 patients with SAH who were admitted to the Neurological Intensive Care Unit of Columbia University Medical Center between July 1996 and September 2002. Patient demographics, 24-hour admission variables, initial CT scan characteristics, daily transcranial Doppler variables, and development of in-hospital complications were analyzed. Odds ratios and 95% CIs for candidate predictors were calculated using multivariate nominal logistic regression.

Results. Admission glucose of at least 126 mg/dl (adjusted OR 1.6; 95% CI 1.0–2.6), admission brain CT scan with a bicaudate index of at least 0.20 (adjusted OR 1.43; 95% CI 1.0–2.0), Fisher Grade 4 (adjusted OR 2.71; 95% CI 1.2–5.7), fourth ventricle hemorrhage (adjusted OR 1.78; 95% CI 1.1–2.7), and development of nosocomial meningitis (adjusted OR 2.2; 95% CI 1.4–3.7) were independently associated with shunt dependency.

Conclusions. These data suggest that permanent CSF diversion after aneurysmal SAH may be independently predicted by hyperglycemia at admission, findings on the admission CT scan (Fisher Grade 4, fourth ventricle intraventricular hemorrhage, and bicaudate index ≥ 0.20), and development of nosocomial meningitis. Future research is needed to assess if tight glycemic control, reduction of fourth ventricle clot burden, and prevention of nosocomial meningitis may reduce the need for permanent CSF diversion after aneurysmal SAH.

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Reinfection following initial cerebrospinal fluid shunt infection

J Neurosurg Pediatrics 6:000–000, 2010. DOI: 10.3171/2010.5.PEDS09457

Significant variation exists in the surgical and medical management of CSF shunt infection. The objectives of this study were to determine CSF shunt reinfection rates following initial CSF shunt infection in a large patient cohort and to determine management, patient, hospital, and surgeon factors associated with CSF shunt reinfection.

Methods. This retrospective cohort study included children who were in the Pediatric Health Information System (PHIS) database, who ranged in age from 0 to 18 years, and who underwent uncomplicated initial CSF shunt placement in addition to treatment for initial CSF shunt infection between January 1, 2001, and December 31, 2008. The outcome was CSF shunt reinfection within 6 months. The main predictor variable of interest was surgical approach to treatment of first infection, which was determined for 483 patients. Covariates included patient, hospital, surgeon, and other management factors.

Results. The PHIS database includes 675 children with initial CSF shunt infection. Surgical approach to treatment of the initial CSF shunt infection was determined for 483 children (71.6%). The surgical approach was primarily shunt removal/new shunt placement (in 286 children [59.2%]), but a substantial number underwent externalization (59 children [12.2%]), of whom a subset went on to have the externalized shunt removed and a new shunt placed (17 children [3.5% overall]). Other approaches included nonsurgical management (64 children [13.3%]) and complete shunt removal without shunt replacement (74 children [15.3%]). The 6-month reinfection rate was 14.8% (100 of 675 patients). The median time from infection to reinfection was 21 days (interquartile range [IQR] 5–58 days). Children with reinfection had less time between shunt placement and initial infection (median 50 vs 79 days, p = 0.06). No differences between those with and without reinfection were seen in patient factors (patient age at either shunt placement or initial infection, sex, race/ethnicity, payer, indication for shunt, number of comorbidities, distal shunt location, and number of shunt revisions at first infection); hospital volume; surgeon volume; or other management factors (for example, duration of intravenous antibiotic use). Nonsurgical management was associated with reinfection, and complete shunt removal was negatively associated with reinfection. However, reinfection rates did not differ between the 2 most common surgical approaches: shunt removal/new shunt placement (44 [15.4%] of 286; 95% CI 11.4%–20.1%) and externalization (total 12 [20.3%] of 59; 95% CI 11.0%–32.8%). Externalization followed by shunt removal/new shunt placement (5 [29.4%] of 17; 95% CI 10.3%–56.0%) and nonsurgical management (15 [23.4%] of 64; 95% CI 13.8%–35.7%) had higher, but nonstatistically significant, reinfection rates. The length of stay was shorter for nonsurgical management.

Conclusions. Surgical approach to treatment of initial CSF shunt infection was not associated with reinfection in this large cohort of patients.

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Endoscopic Third Ventriculostomy Vs Cerebrospinal Fluid Shunt in the Treatment of Hydrocephalus in Children: A Propensity Score–Adjusted Analysis

Neurosurgery 67:588-593, 2010 DOI: 10.1227/01.NEU.0000373199.79462.21

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 patientrelated 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.

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Adjustable shunt valve–induced magnetic resonance imaging artifact: a comparative study

J Neurosurg 113:74–78, 2010. (DOI: 10.3171/2009.9.JNS09171)

In this paper, the authors’ goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences.

Methods. The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences.

Results. Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm3 on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm3, p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequencse for both valve types.

Conclusions. Adjustable valve–induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact–inducing adjustable shunt valves.

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Selection of patients with idiopathic normal-pressure hydrocephalus for shunt placement: a single-institution experience

J Neurosurg 113:64–73, 2010. DOI: 10.3171/2010.1.JNS091296

The ability to predict outcome after shunt placement in patients with idiopathic normal-pressure hydrocephalus (NPH) represents a challenge. To date, no single diagnostic tool or combination of tools has proved capable of reliably predicting whether the condition of a patient with suspected NPH will improve after a shunting procedure. In this paper, the authors report their experience with 120 patients with the goal of identifying CSF hydrodynamics criteria capable of selecting patients with idiopathic NPH. Specifically, they focused on the comparison between CSF-outflow resistance (R-out) and intracranial elastance (IE).

Methods. Between January 1977 and December 2005, 120 patients in whom idiopathic NPH had been diagnosed (on the basis of clinical findings and imaging) underwent CSF hydrodynamics evaluation based on an intraventricular infusion test. Ninety-six patients underwent CSF shunt placement: 32 between 1977 and 1989 (Group I) on the basis of purely clinical and radiological criteria; 44 between 1990 and 2002 (Group II) on the basis of the same criteria as Group I and because they had an IE slope > 0.25; and 20 between 2003 and 2005 (Group III) on the basis of the same criteria as Group II but with an IE slope ≥ 0.30. Outcomes were evaluated by means of both Stein-Langfitt and Larsson scores. Patients’ conditions were considered improved when there was a stable decrease (at 6- and 12-month follow-up) of at least 1 point in the Stein-Langfitt score and 2 points in the Larsson score.

Results. Group I: while no statistically significant difference in mean R-out value between improved and unimproved cases was observed, a clear-cut IE slope value of 0.25 differentiated very sharply between unimproved and improved cases. Group II: R-out values in the 2 unimproved cases were 20 and 47 mm Hg/ml/min, respectively. The mean IE slope in the improved cases was 0.56 (range 0.30–1.4), while the IE slopes in the 2 unimproved cases were 0.26 and 0.27. Group III: the mean IE slope was 0.51 (range 0.31–0.7). The conditions of all patients improved after shunting. A significant reduction of the Evans ratio was observed in 34 (40.5%) of the 84 improved cases and in none of the unimproved cases.

Conclusions. Our strategy based on the analysis of CSF pulse pressure parameters seems to have a great accuracy in predicting surgical outcome in clinical practice.

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