Fixed-pressure Valves Research Articles

Choosing wisely: adjustable or fixed pressure valves for patients with idiopathic normal hydrocephalus? A systematic review and meta-analysis on ventriculoperitoneal shunt outcomes

Choosing wisely: adjustable or fixed pressure valves for patients with idiopathic normal hydrocephalus? A systematic review and meta-analysis on ventriculoperitoneal shunt outcomes

Treatment of Idiopathic Normal Pressure Hydrocephalus with a Novel Programmable Valve: Prospective Evaluation of Costs, Efficacy, and Safety.

Objective Programmable valves provide an equal or superior neurological outcome when compared with fixed pressure ones, with fewer complications, in treating idiopathic normal pressure hydrocephalus (iNPH) patients. Long-term costs of these treatments have not been properly compared in literature. We sought to compare costs, efficacy, and safety of 1-year treatment of iNPH patients with programmable valve Sphera Pro and a fixed pressure valve. Materials and Methods A prospective cohort of iNPH patients treated with programmable valve was compared with a historical cohort of iNPH patients treated with fixed pressure valve. Our primary outcome was mean direct cost of treating iNPH up to 1 year. Efficacy in treating iNPH and safety were assessed as secondary outcomes. Statistical Analysis Proportions were compared using chi-square or Fisher's exact tests. Normally distributed variables were compared using the Student's t -test or the Mann-Whitney's U test. Differences in the evolution of the variables over time were assessed using generalized estimating equations. All tests were two-sided, with an α of 0.05. Results A total of 19 patients were analyzed in each group (mean age 75 years, the majority male). Comorbidities and clinical presentation were similar between groups. Both fixed pressure and programmable valve patients had neurological improvement over time ( p < 0.001), but no difference was seen between groups ( p = 0.104). The fixed pressure valve group had more complications than the programmable valve group (52.6% vs. 10.5%, respectively, p = 0.013). Annual treatment cost per patient was US$ 3,820 ± 2,231 in the fixed pressure valve group and US$ 3,108 ± 553 in the programmable valve group. Mean difference was US$712 (95% confidence interval, 393-1,805) in favor of the programmable valve group. Conclusion The Sphera Pro valve with gravitational unit had 1 year treatment cost not higher than that of fixed pressure valve, and resulted in similar efficacy and fewer complications.

410 Treatment of Idiopathic Normal Pressure Hydrocephalus With a Novel Programmable Valve With Gravitational Unit: Prospective Evaluation of Efficacy, Safety and Costs

INTRODUCTION: Programmable valves provide an equal or superior neurological outcome when compared to fixed pressure ones, with fewer complications, in treating idiopathic normal pressure hydrocephalus (iNPH) patients. Long-term costs of these treatments have not been properly compared in literature. METHODS: A prospective cohort of iNPH patients treated with programmable valve between January 2018 and May 2020 was compared to a historical cohort of iNPH patients treated with fixed pressure valve from January 2016 through December 2017. Our primary outcome was the mean cost of treating iNPH up to one year. Cost variables assessed included number of surgeries, length of ICU and hospital stay, and number of imaging tests. Efficacy in treating iNPH, measured by mean NPH Japanese Scale, and safety, measured by complications rates, were assessed as secondary outcomes. RESULTS: A total of 19 patients were analyzed in each group (mean age 75 years, the majority male). Comorbidities and clinical presentation were similar between groups. Both fixed pressure and programmable valve patients had neurological improvement over time (p &lt; 0.001), but no difference was seen between groups (p = 0.104). The fixed pressure valve group had more complications than programmable valve group (52.6% vs 10.5%, respectively, p = 0.013). Annual treatment cost per patient was US$ 3,820 ± 2,231 in the fixed pressure valve group and US$ 3,108 ± 553 in the programmable valve group. Mean difference was US$712 (95% CI, 393 – 1,805) in favor of the programmable valve group. CONCLUSIONS: The novel programmable valve with gravitational unit had one-year treatment cost not higher than that of fixed-pressure valve, and resulted in similar efficacy and fewer complications.

From fixed-pressure paediGAV to programmable proGAV/proSA serial valves for pediatric hydrocephalus within the 1st year of life: a technical single-center analysis.

Programmable valves have gained increasing popularity in the complex treatment of pediatric hydrocephalus. Over the last decade, adjustable serial valves have gradually replaced fixed-pressure valves in the authors' department. The present study investigates this development by analyzing shunt- and valve-related outcomes for this vulnerable population. A retrospective analysis of all shunting procedures between January 2009 and January 2021 in children younger than 1 year of age was performed at the authors' single-center institution. Postoperative complications and surgical revisions were set as outcome parameters. Shunt and valve survival rates were evaluated. Statistical analysis compared children who underwent implantation of the Miethke proGAV/proSA programmable serial valves with those who underwent implantation of the fixed-pressure Miethke paediGAV system. Eighty-five procedures were evaluated. The paediGAV system was implanted in 39 cases and the proGAV/proSA in 46 cases. The mean ± SD follow-up was 247.7 ± 140 weeks. In 2009 and 2010, paediGAV valves were used exclusively, but by 2019, the use of proGAV/proSA had evolved into the first-line therapy. The paediGAV system was significantly more often revised (p < 0.05). The main indication for revision was proximal occlusion, with or without impairment to the valve. The valve and shunt survival rates of proGAV/proSA were significantly prolonged (p < 0.05). The surgery-free valve survival of proGAV/proSA was 90% after 1 year and 63% after 6 years. There were no overdrainage-related revisions of proGAV/proSA valves. Favorable shunt and valve survival validates the increasing use of programmable proGAV/proSA serial valves in this delicate population. Potential benefits in postoperative treatment should be addressed in prospective multicenter studies.

Use of programmable valve versus fixed pressure valve in the treatment of idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis.

Use of programmable valve versus fixed pressure valve in the treatment of idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis.

Incidental and Clinical Significance of Slit Ventricles in Fixed Pressure Valves.

Slit ventricle syndrome (SVS) is arecognizeddelayed complication ofcerebrospinal fluid (CSF) shuntingin children. Ithad beenlinked to the use of low-pressureshuntsandconsidered anargument for the use of programmablevalves.In this study, weaim to assess the rate of SVSin childrenthat wereshuntedusingfixed-pressure valves. This study is a retrospective cohort study that occurred in King Abdulaziz Medical City, Jeddah, which reviews 100 patients with a median age of 15.5 months that were shunted by using fixed pressure valves during the period from 2010 to 2018. Fixed low-pressure valves were used in 69% of patients, while fixed medium-pressure valves were used in 31% of patients.SVS was defined by the presence ofslit-like ventricles (fronto-occipital [F-O] hornsratiowas ≤ 0.2 onanypost-shunt CT scan)andthe occurrence ofslit-like ventricle-related symptoms (chronic headache, nausea, vomiting,andaltered conscious level_ in theabsence ofother causes of shunt malfunction. The overall SVS ratein thecohortwas 6%. Nine childrenhadslit-like ventricles, butonly six of themwere symptomatic. Relatively higherSVSrateswereobservedinyoungermale children,obstructivehydrocephalus,andmedium-pressure valves.Slit-like ventricle-related symptoms in the absence of a slit-like ventriclewere reported in 24 out of 91 (26%)patients.A total of42 patients underwent shunt revisions for other complications.AllSVSpatients were treated conservatively.There was a temporal fluctuationin the F-O horns ratio andinsome patientswithSVStheirF-Ohornsratio returnedto normal atfurtherfollow-up without intervention. The overall SVS ratefollowing the use offixed-pressure CSFvalves in children is lowand managed conservatively. Not all patients withslit-like ventricles are symptomaticand the radiological appearance of SVS may improveon further follow-up without intervention.Fixed pressure valves remainan acceptabledevice inthetreatment of hydrocephalus in children.

From Shunt to Recovery: A Multidisciplinary Approach to Hydrocephalus Treatment in Severe Acquired Brain Injury Rehabilitation.

Background: Hydrocephalus among Severe Acquired Brain Injury (SABI) patients remains overlooked during rehabilitation. Methods: A retrospective cohort study was carried out of traumatic and non-traumatic SABI patients with hydrocephalus, consecutively admitted over 9 years in a tertiary referral specialized rehabilitation hospital. Patients were treated with ventriculoperitoneal shunt before or during inpatient rehabilitation and assessed using the Level of Cognitive Functioning Scale and Disability Rating Scale. Logistic regression models were used to identify predictors of post-surgical complications. Linear regression models were used to investigate predictors of hospital length of stay (LOS), disability, and cognitive function. Results: Of the 82 patients, 15 had post-surgical complications and 16 underwent cranioplasty. Shunt placement complication risk was higher when fixed vs. when programmable pressure valves were used. A total of 56.3% achieved functional improvement at discharge and 88.7% improved in cognitive function; of the 82 patients, 56% were discharged home. In multiple regression analyses, higher disability at discharge was related to cranioplasty and longer LOS, while poorer cognitive function was associated with cranioplasty. Increase in LOS was associated with increasing time to shunt and decreasing age. Conclusions: A significant improvement in cognitive and functional outcomes can be achieved. Cranioplasty increased LOS, and fixed pressure valves were related to poorer outcomes.

Shunt performance in 349 patients with hydrocephalus after aneurysmal subarachnoid hemorrhage

BackgroundShunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage (aSAH) is a common sequelae leading to poorer neurological outcomes and predisposing to various complications.MethodsA total of 2191 consecutive patients with aSAH were acutely admitted to the Neurointensive Care at the Kuopio University Hospital between 1990 and 2018 from a defined population. A total of 349 (16%) aSAH patients received a ventriculoperitoneal shunt, 101 with an adjustable valve (2012–2018), 232 with a fixed pressure valve (1990–2011), and 16 a valveless shunt (2010–2013). Clinical timelines were reconstructed from the hospital records and nationwide registries until death (n = 120) or June 2019.ResultsComparing the adjustable valves vs. the fixed pressure valves vs. the valveless shunts, intraventricular hemorrhage was present in 61%, 44% and 100%, respectively. The median times to the shunt were 7 days vs. 38 days vs. 10 days. The rates of the first revision were 25% vs. 32% vs. 69%. The causes included infection in 11% vs. 7% vs. 25% and overdrainage in 1% vs. 4% vs. 31%. The valveless shunt was the only independent risk factor (HR 2.9) for revision. After the first revision, more revisions were required in 48% vs. 52% vs. 45%.ConclusionsThe protocol to shunt evolved over time to favor earlier shunt. In post-aSAH hydrocephalus, adjustable valve shunts, without anti-siphon device, can be installed at an early phase after aSAH, in spite of intraventricular blood, with a modest risk (25%) of revision. Valveless shunts are not recommendable due to high risk of revisions.

Efficacy and safety of the Miethke programmable differential pressure valve (proGAV\xae2.0): a single-centre retrospective analysis

PurposeAchieving decompression without CSF over-drainage remains a challenge in hydrocephalus. Differential pressure valves are a popular treatment modality, with evidence suggesting that incorporation of gravitational units helps minimise over-drainage. This study seeks to describe the utility of the proGAV®2.0 programmable valve in a paediatric population.MethodsClinical records and imaging of all patients fitted with proGAV®2.0 valves and Miethke fixed-pressure valves between 2014 and 2019 at our tertiary centre were analysed. Patient demographics, indication for shunt and valve insertion/revision and time to shunt/valve revision were collected. Ventricular linear metrics (fronto-occipital horn ratio (FOHR) and fronto-occipital horn width ratio (FOHWR)) were collected pre- and post-valve insertion. Microsoft Excel and SPSS v24 were used for data collection and statistical analysis.ResultsEighty-eight proGAV®2.0 valves were inserted in a population of 77 patients (n = 45 males (58%), mean age 5.1 years (IQR: 0.4–11.0 years)). A total of 102 Miethke fixed-pressure valves were inserted over the same time period. Median follow-up was 17.5 months (1.0–47.3). One (1.1%) proGAV®2.0 was revised due to over-drainage, compared to 2 (1.9%) fixed-pressure valves (p > 0.05). ProGAV®2.0 insertion resulted in a significant decrease in the mean number of revisions per patient per year (1.77 vs 0.25; p = 0.01). Overall shunt system survival with the proGAV®2.0 was 80.4% at 12 months, and mean time to revision was 37.1 months, compared to 31.0 months (95%CI: 25.7–36.3) and 58.3% in fixed-pressure valves (p < 0.01). Significant decreases were seen following proGAV®2.0 insertion in both FOHR and FOHWR, by 0.014 (95%CI: 0.006–0.023, p = 0.002) and 0.037 (95%CI: 0.005–0.069, p = 0.024) respectively.ConclusionThe proGAV®2.0 provides effective decompression of hydrocephalic patients, significantly reduces the number of valve revisions per patient and had a significantly greater mean time to revision than fixed-pressure valves.

Adjustable pressure valves for chronic hydrocephalus following subarachnoid hemorrhage: Is it worthwhile?

ObjectiveCompared to fixed pressure valves (FPV), adjustable pressure valves (APV) might reduce the rates of over/underdrainage necessitating revision surgery after shunt placement. But due to higher implant costs and valve vulnerability, the use APV in neurosurgery is still limited. The aim of this study was to evaluate the clinical utility of APV in patients with aneurysmal subarachnoid hemorrhage (aSAH). Material and MethodsAll consecutive aSAH patients undergoing ventriculoperitoneal shunt (VPS) placement at our institution between 2003 and 2016 were eligible. Rates and the risk factors for shunt valve dysfunction and over/underdrainage were evaluated. ResultsA total of 189 patients were included in the final analysis. FPV were implanted in the majority of patients (173/91.5 %). Revision surgery due to over/underdrainage was performed in 8 (4.6 %) cases with FPV and in no case with APV. Higher patients’ age (>65 years, p = 0.011; aOR 10.36) and bone flap reimplantation following decompressive craniectomy (p = 0.044; aOR 6.53) independently predicted the need for revision surgery for over/underdrainage. There was no difference in the occurrence of valve dysfunction between the two valve types (1 [6.3 %] APV, 12 [6.9 %] FPV), p > 0.99). Patients requiring revision surgery for over/underdrainage had a higher risk for unfavorable outcome at 6 months follow-up (mRS>3, p = 0.009; aOR = 8.0). ConclusionAPV is a valuable option for aSAH individuals undergoing VPS implantation to reduce the need for revision surgery for over/underdrainage. Particularly, elderly patients and those requiring bone flap reimplantation might benefit from APV.

Management of paediatric hydrocephalous with Miethke fixed pressure gravitational valves. The Alder Hey Children's Hospital experience.

The management of paediatric hydrocephalous remains challenging with the complication and revision rates being consistent in the literature. We hypothesise that the use of a fixed pressure gravitational valve for all de novo shunt insertions decreases the rate of functional revisions and that by implementing the routine use of gravitational valves in children, we would see a reduction in over-drainage and slit ventricle syndrome. Retrospective data collection in a single centre, between February 2010 and August 2018. All patients undergoing fixed pressure gravitational Miethke valve insertion were included. We collected data on patients' demographics, reason for shunt insertion, type of valve and time to and reason for first revision. Data analysis was done with SPSS. A total of 235 patients were included in our study (124 males, 111 females), aged from 0 to 18.6years (median 0.28). A total of 99 shunt revisions were documented, 30 of which secondary to ventricular catheter malfunction and 28 secondary to infection. The overall mechanical valve survival rates were 88.5%, 86.4% and 85.5% at 1, 2 and 5years, respectively. Shunt revision due to over-drainage was documented in only 3 cases (1.3%). Our results are in agreement with existing literature regarding shunt failures secondary to all extrinsic factors to the valve (infection and mechanical failure). We have shown that the use of a Miethke fixed pressure valve for all de novo shunt insertions in paediatric hydrocephalus decreases the need for functional revisions with valve survival rates being superior to the ones described for other types.

Hydrocephalus – Focus Session

Dear Reader, You are receiving the second volume of Archives of Pediatric Neurosurgery. This is an electronic journal from the Brazilian Society of Pediatric Neurosurgery, which is published quarterly. We are dedicating this volume to hydrocephalus-related topics. Hydrocephalus is one of the most important topics in pediatric neurosurgery and is related to up to 40% of the activities performed in many specialized services. With its multiple etiologies and variety of proposed treatment modalities, this disease presents a huge challenge, and many questions have not been answered. When focusing on fetal hydrocephalus, we still cannot determine which fetuses will benefit from treatment during the fetal period. The answers are also unclear as to why surgery for myelomeningocele correction performed under 27 weeks of gestation decreases the prevalence of hydrocephalus. What is the best treatment for intraventricular hemorrhage in premature infants: Brain Washing, external ventricular drainage, ventriculosubgaleal shunt, reservoir placement and repeated punctures or lumbar punctures? Furthermore, what is the best treatment for hydrocephalus in cases of posterior fossa tumor: Placing an external ventricular drain and resecting the tumor, performing a third ventriculostomy or placing a ventriculoperitoneal shunt, considering that in cases of giant tumors in each of these situations, ascending herniations can occur? Of course, the procedure selected will be related to the dynamics, volume and expertise of the treatment center. Regarding valves, we know that the number of shunts implanted annually is enormous and that the market for valves is divided among several companies that manufacture these prostheses. Which valve is the best? An anti-gravitational one, a programmable one, one with an anti-siphon mechanism? Fixed-pressure valves, valves that produce fewer MRI artifacts, those that do not experience pressure changes due to MRI, or those impregnated with antibiotics? How can a simple valve work as well as a valve with a complex system? Why does a valve system cost $1,000 in one country but costs ten times more in another country? Why are some types of valves sold only in underdeveloped countries? How can we avoid or minimize biological and mechanical complications after valve placement? Even neuroendoscopic procedures that have been performed for more than 25 years in Brazil are not free of complications such as bleeding, infection and technical incapacity of the professional. Nevertheless, we believe that all services that treat children with hydrocephalus should be able to provide neuroendoscopic procedures, thus decreasing the number of shunts placed. We hope that this volume can answer some of these questions. I invite you to participate in Archives of Pediatric Neurosurgery by contributing scientific articles focusing on pediatric neurosurgery. This volume was compiled during the coronavirus (COVID-19) pandemic. We hope that this disease will be controlled quickly, allowing us to return to our normal activities. We also hope that pregnant women will not transmit the disease to their fetuses, causing hydrocephalus, as was observed in the last Zika virus epidemic. Sincerely, Sergio Cavalheiro Editor-in-chief, Archives of Pediatric Neurosurgery

Exclusive use of fixed pressure valves for cerebrospinal fluid diversion in a modern adult cohort

BackgroundThere is extensive debate on the role of fixed pressure shunts in the adult population. Most studies assessing fixed pressure valves do not consider the potential for changes in technique and management of shunts. We sought to examine the natural history of fixed pressure. MethodsWe conducted a retrospective chart review of 169 patients undergoing shunt placement by the senior author Daniel Wecht (DW). The etiology of shunt placement, shunt failure rates, and outcome data was assessed for each patient. ResultsOverall, 126 patients underwent initial shunt placement. Thirty-three (26.2%) patients required at least one shunt revision during follow-up. The most common cause of first time revision was mechanical shunt malfunction (13, 39.4%), followed by infection (7, 21.2%), and shunt migration (6, 18.2%). Three patients (9.1%) required revision due to misplaced catheters. Underdrainage or overdrainage of shunts each resulted in revisions for 2 (6.1%) patients. The mean follow-up length was 28.1 ± 6.1 months. ConclusionFixed pressure shunts failed primarily because of shunt malfunction and occurred most commonly in patients developing hydrocephalus as a result of hemorrhage or normal pressure hydrocephalus (NPH). The overall failure rate between these two groups was proportionally equivalent. Both overdrainage or underdrainage were found to be rare indications for revision.

Comparative durability and costs analysis of ventricular shunts.

Ventricular shunt (VS) durability has been well studied in the pediatric population and in patients with normal pressure hydrocephalus; however, further evaluation in a more heterogeneous adult population is needed. This study aims to evaluate the effect of diagnosis and valve type-fixed versus programmable-on shunt durability and cost for placement of shunts in adult patients. The authors retrospectively reviewed the medical records of all patients who underwent implantation of a VS for hydrocephalus at their institution over a 3-year period between August 2013 and October 2016 with a minimum postoperative follow-up of 6 months. The primary outcome was shunt revision, which was defined as reoperation for any indication after the initial procedure. Supply costs, shunt durability, and hydrocephalus etiologies were compared between fixed and programmable valves. A total of 417 patients underwent shunt placement during the index time frame, consisting of 62 fixed shunts (15%) and 355 programmable shunts (85%). The mean follow-up was 30 ± 12 (SD) months. The shunt revision rate was 22% for programmable pressure valves and 21% for fixed pressure valves (HR 1.1 [95% CI 0.6-1.8]). Shunt complications, such as valve failure, infection, and overdrainage, occurred with similar frequency across valve types. Kaplan-Meier survival curve analysis showed no difference in durability between fixed (mean 39 months) and programmable (mean 40 months) shunts (p = 0.980, log-rank test). The median shunt supply cost per index case and accounting for subsequent revisions was $3438 (interquartile range $2938-$3876) and $1504 (interquartile range $753-$1584) for programmable and fixed shunts, respectively (p < 0.001, Wilcoxon rank-sum test). Of all hydrocephalus etiologies, pseudotumor cerebri (HR 1.9 [95% CI 1.2-3.1]) and previous shunt malfunction (HR 1.8 [95% CI 1.2-2.7]) were found to significantly increase the risk of shunt revision. Within each diagnosis, there were no significant differences in revision rates between shunts with a fixed valve and shunts with a programmable valve. Long-term shunt revision rates are similar for fixed and programmable shunt pressure valves in adult patients. Hydrocephalus etiology may play a significant role in predicting shunt revision, although programmable valves incur higher supply costs regardless of initial diagnosis. Utilization of fixed pressure valves versus programmable pressure valves may reduce supply costs while maintaining similar revision rates. Given the importance of developing cost-effective management protocols, this study highlights the critical need for large-scale prospective observational studies and randomized clinical trials of ventricular shunt valve revisions and additional patient-centered outcomes.

Performance of the fixed pressure valve with antisiphon device SPHERA® in the treatment of normal pressure hydrocephalus and prevention of overdrainage

Normal pressure hydrocephalus (NPH) is characterized by the triad of gait apraxia, dementia and urinary incontinence associated with ventriculomegaly and normal pressure of cerebrospinal fluid. Treatment is accomplished through the implantation of a ventricular shunt (VPS), however some complications are still frequent, like overdrainage due to siphon effect. This study analyses the performance of a valve with anti-siphon device (SPHERA®) in the treatment of patients with NPH and compares it with another group of patients with NPH who underwent the same procedure without anti-siphon mechanism (PS Medical® valve). 30 patients were consecutively enrolled in two groups with 15 patients each and followed clinically and radiologically for 1 year. Patients submitted to VPS with SPHERA® valve had the same clinical improvement as patients submitted to VPS with PS Medical®. However, complications and symptomatology due to overdrainage were significantly lower in SPHERA® group, suggesting it as a safe tool to treat NPH.

Role of Endoscopic Third Ventriculostomy and Ventriculoperitoneal Shunt in Idiopathic Normal Pressure Hydrocephalus

Currently, the most common treatment for idiopathic normal pressure hydrocephalus (INPH) is a ventriculoperitoneal shunt (VPS), generally with programmable valve implantation. Endoscopic third ventriculostomy (ETV) is another treatment option, and it does not require prosthesis implantation. To compare the functional neurological outcome in patients after 12 months of treatment with INPH by using 2 different techniques: ETV or VPS. Randomized, parallel, open-label trial involving the study of 42 patients with INPH and a positive response to the tap test, from January 2009 to January 2012. ETV was performed with a rigid endoscope with a 30° lens (Minop, Aesculap), and VPS was performed with a fixed-pressure valve (PS Medical, Medtronic). The outcome was assessed 12 months after surgery. The neurological function outcomes were based on the results of 6 clinical scales: mini-mental, Berg balance, dynamic gait index, functional independence measure, timed up and go, and normal pressure hydrocephalus. There was a statistically significant difference between the 2 groups after 12 months of follow-ups, and the VPS group showed better improvement results (ETV = 50%, VPS = 76.9%). Compared with ETV, VPS is a superior method because it had better functional neurological outcomes 12 months after surgery.

Performance of fixed-pressure valve with antisiphon device SPHERA® in hydrocephalus treatment and overdrainage prevention

Patients with hydrocephalus and risk factors for overdrainage may be submitted to ventricular shunt (VS) implant with antisiphon device. The objective of this study was to prospectively evaluate for two years the clinical and tomographic results of the implant of fixed-pressure valves with antisiphon device SPHERA(®) in 35 adult patients, with hydrocephalus and risk factors for overdrainage. Of these, 3 had congenital hydrocephalus in adult patients with very dilated ventricles (Evans index >50%), 3 had symptomatic overdrainage after previous VS implant (subdural hematoma, hygroma or slit ventricle syndrome), 1 had previous chronic subdural hematoma, 15 had normal pressure hydrocephalus with final lumbar pressure <5 cm H(2)O after tap test (40 mL), 6 had pseudotumor cerebri, and 7 had hydrocephalus due to other causes. Clinical improvement was observed and sustained in 94.3% of the patients during the two-year period with no computed tomography (CT) evidence of hypo or overdrainage, and no immediate early or late significant complications.

Clinical Experience of Ventriculoperitoneal Shunt Dysfunction in a Patient with Hydrocephalus after Brain Injury: A casereport

We report a case of an adult patient with post-traumatic hydrocephalus who was treated using a ventriculoperitoneal (VP) shunt with a fixed pressure setting valve. Slit ventricle syndrome was found two months later and an antisiphon device (ASD) was added. A fixed pressure valve with ASD was found not to be optimal in terms of improving his neurological symptoms and a programmable valve system was therefore implanted with a pressure setting of 140 mmH2O in the beginning. The valve then was gradually programmed to reduce down to 70 mmH2O over two months. This case demonstrates that selection of a shunting device is difficult, and even after deliberate selection and use of an antisiphon device, slit ventricle syndrome could not be avoided. In addition, the patient in this case had increased episodes of seizure that were associated with acute intracranial hypertension; these were caused by obstruction. Good clinical monitoring of such patients is needed because of the intermittent nature of the high intracranial pressure symptoms. Notwithstanding this, minor complications involving shunt dysfunction may be neglected once the initial treatment has been completed in the neurosurgical ward and the patient has been transferred to a rehabilitation ward. It should be noted that this patient was very sensitive to over-drainage and siphoning was required in order to generate an effective transmantle pressure gradient. Thus, the highest valve setting available was used at the beginning of treatment and this was followed by a methodically lowering of the opening pressure based on the clinical response and computed tomography findings. Overall, the programmable valve shunt system would seem to be more effective when there is a need to deal with shunt dysfunction non-invasively.

Are adjustable valves effective? Data from the UK Shunt Registry

Background Adjustable (often-called programmable) CSF valves have been developed by several manufacturers. These valves are more expensive, but have an advantage in that the operating pressure of the valve can be altered by the use of an external magnet as a simple procedure. The proportion of these valves used in the UK and Ireland has increased from 4.9% in 2000 to 22.4% in 2006. We have used data collected by the UK Shunt Registry to assess the effectiveness of these valves in reducing valve replacement for under and over-drainage using a case-control design. Materials and methods The UK Shunt Registry contains data on nearly 30,000 CSF shunt-related procedures. Our data suggests that primary factors involved in shunt revision are patient age, diagnosis and the number of revisions a patient has had. Procedures were identified where either a Medtronic Strata Valve or Codman Hakim Programmable Valve was used. Of these 1,389 had an accurate diagnosis and age entered and we were able to determine the exact number of shunt revisions. A database search was performed for procedures matched for patient age, diagnosis and revision status but using Medtronic or Codman fixed-pressure valves. Matches were found for 943 procedures.

818 Use of Programmable Valves to Prevent Overshunting Complications in Infants

INTRODUCTION: Hydrocephalus remains a common neurosurgical problem in the pediatric population. Despite the advent of newer interventions such as third ventriculostomy, ventriculoperitoneal shunting remains a mainstay of therapy. Because of the unique anatomy of the infant cranium (e.g., open cranial sutures), overshunting complications such as overriding parietal bones and microcephaly may be encountered with the use of fixed-pressure valves. We describe the use of programmable valves in infants requiring ventricular cerebrospinal fluid (CSF) drainage to prevent overshunting complications. METHODS: We retrospectively examined 22 patients who underwent placement of a programmable ventriculoperitoneal shunting device during the perinatal period for treatment of hydrocephalus at the University of California, San Francisco Medical Center. Mean follow-up period was 1.5 years. Valves were set at low pressures (30 mm Hg) at insertion. Pressure settings were increased to 150 mm Hg at the 1-month interval. Head circumference measurements were taken at presentation, at surgery, and at 1-, 3-, 6-, and 12-month intervals. Data were analyzed for number of subsequent valve adjustments, number of revisions, and incidence of all complications. RESULTS: All patients underwent successful placement of a programmable ventriculoperitoneal shunting device. Two patients underwent removal and replacement of the device secondary to infection. Seven patients underwent revision secondary to malfunction. Mean head circumference measurements remained between the 50th and 90th percentiles for age throughout the follow-up period. CONCLUSION: The reported incidence of CSF overdrainage secondary to ventriculoperitoneal shunting varies between 5 and 55%. These potential complications include intracranial hypotension, low-pressure syndromes, slit ventricle syndrome, intracranial hemorrhage, cranial deformities, and microcephaly. No overshunting complications were observed in this study population. We conclude that the advent of programmable valves may provide neurosurgeons with an additional tool in preventing complications of overshunting in infants with hydrocephalus.