Seven years of clinical experience with the programmable Codman Hakim valve: a retrospective study of 583 patients

The Top 100 Most Cited Journal Articles on Hydrocephalus

Hydrocephalus represents a significant burden of disease, with more than 383,000 new cases annually worldwide. When the magnitude of this condition is considered, a centralized archive of pertinent literature is of great clinical value. From a neurosurgical standpoint, hydrocephalus is one of the most frequently treated conditions in the field. The focus of this study was to identify the top 100 journal articles specific to hydrocephalus using bibliometric analysis. Using the Journal of Citation Report database, 10 journals were identified. The Web of Science Core Collection was then searched using each journal name and the search term "hydrocephalus." The results were ordered by "Times Cited" and searched by the number of citations. The database contained journal articles from 1976 to 2021, and the following variables were collected for analysis: journal, article type, year of publication, and the number of citations. Journal articles were excluded if they had no relation to hydrocephalus, mostly involved basic science research, or included animal studies. Ten journals were identified using the above criteria, and a catalog of the 100 most cited publications in the hydrocephalus literature was created. Articles were arranged from highest to lowest citation number, with further classification by journal, article type, and publication year. Of the 100 articles referenced, 38 were review articles, 24 were original articles, 15 were comparative studies, 11 were clinical trials, six were multi-center studies, three were cross-sectional, and three were case reports with reviews. Articles were also sorted by study type and further stratified by etiology. If the etiology was not specified, studies were instead subcategorized by treatment type. Etiologies such as aqueductal stenosis, tumors, and other obstructive causes of hydrocephalus were classified as obstructive (n=6). Communicating (n=15) included idiopathic, normal pressure hydrocephalus, and other non-obstructive etiologies. The category "other" (n=3) was assigned to studies that included etiologies, populations, and/or treatments that did not fit into the classifications previously outlined. Through our analysis of highly cited journal articles focusing on different etiologies and the surgical or medical management of hydrocephalus, we hope to elucidate important trends. By establishing the 100 most cited hydrocephalus articles, we contribute one source, stratified for efficient referencing, to facilitate clinical care and future research on hydrocephalus.

Dual catheter and double-lumen cerebrospinal fluid shunt systems with backflow mechanisms

PURPOSE

We previously developed a novel functional benchtop apparatus to simulate catheter occlusion in vitro utilizing avian vitelline membrane and chalaza to test catheter designs and de-obstruction techniques. Here, we study the integration of double-lumen catheter-mediated backflow in the shunt system assembly and its potential for an in-line de-obstruction of an obstructed ventricular catheter.

METHODS

A double-lumen catheter was connected to a standard proximal shunt catheter for all trials. One limb of the double-lumen catheter was connected to the backflow mechanisms and allowed to loop back for fluid access. A micropump and a bi-corporal electromagnetic pump were utilized to provide various degrees of backflow at predetermined intervals. Flow rates were measured after initial occlusion and after implementation of the backflow mechanisms, and degrees of catheter blockage was calculated as a percentage of the unoccluded flow rate. Flow visualization was also used.

RESULTS

In baseline blockage of less than 50%, the average occluding agent weighed 0.3-0.6 g with baseline flow rates of 8.5-11.9 mL/min. After 5 min of backflow using a micropump, the degree of blockage was reduced in 50% of trials. Additional backflow for 5 min did not provide further improvements in flow rate. In baseline blockage of greater than 50%, the average occluding agent weighed 0.8-1.3 g with baseline flow rates of 1.1-4.2 mL/min. After 5 min of backflow, the system demonstrated a decreased blockage in 20% of trials; additional backflow for 5 min further improved the flow rate in 40% of the total trials. Only magnetic plates provided enough force to provide pulsatile backflow in the bi-corporal electromagnetic system.

CONCLUSIONS

The preliminary results of connecting a standard proximal catheter in series with a double-lumen catheter show a slight change in the percent occlusion from the baseline status several times when the retrograde flow occurred via one limb of the catheter. Additionally, the de-obstruction seems related to the length of the interval of the backflow and the initial percentage occlusion of the proximal catheter. The statistical analysis does not reveal a statistically significant reduction in occlusion in the proximal catheter with either backflow interval.

Toward the "Perfect" Shunt: Historical Vignette, Current Efforts, and Future Directions

As a concept, drainage of excess fluid volume in the cranium has been around for more than 1000 years. Starting with the original decompression-trepanation of Abulcasis to modern programmable shunt systems, to other nonshunt-based treatments such as endoscopic third ventriculostomy and choroid plexus cauterization, we have come far as a field. However, there are still fundamental limitations that shunts have yet to overcome: namely posture-induced over- and underdrainage, the continual need for valve opening pressure especially in pediatric cases, and the failure to reinstall physiologic intracranial pressure dynamics. However, there are groups worldwide, in the clinic, in industry, and in academia, that are trying to ameliorate the current state of the technology within hydrocephalus treatment. This chapter aims to provide a historical overview of hydrocephalus, current challenges in shunt design, what members of the community have done and continue to do to address these challenges, and finally, a definition of the "perfect" shunt is provided and how the authors are working toward it.

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.

Pressure control cam displacement in the Codman-Hakim programmable valve after a 3T MRI: Case report and review of the literature

Pressure control cam dislocation is a rare finding in patients with a programmable shunt valve that should be considered when evaluating patients with signs and symptoms of shunt malfunction. The objective of this paper is to review the mechanism, clinical presentation, and radiographic findings associated with pressure control cam (PCC) dislocation, in addition to presenting a novel case to add to the scarce literature on this topic. A systematic review of the literature were performed using PubMed, Embase, and Cochrane from database inception. PCC dislocation is exceedingly rare and can present with no symptoms, positional headache, neck pain, nausea, or vomiting. Skull x-ray findings demonstrate a clear black "X" at the distal end of the valve, due to the PCC disarticulation from atop the base plate of the plastic valve housing. Intraoperatively, a "Y"-shaped crack atop the plastic valve housing may be present and the PCC may be fully separated from the shunt or found at the distal end of the plastic valve housing. Prior reports of dislocation of the PCC have occurred 7-9 years after implantation, with inciting events including direct trauma, programmable valve adjustment, and utilization 3-Tesla magnetic resonance image scan.

Mechanical Complications of Sophysa SM8 Shunt in Adult Hydrocephalus: A Monocentric Experience

BACKGROUND

Sophysa SM8 is widely used by neurosurgeons in France. Published studies report shunt malfunction rates in adults between 18% and 29%. However, these studies included multiple valve types and thus entailed a serious confounding factor.

OBJECTIVE

To ascertain the incidence the Sophysa SM8 cerebrospinal fluid (CSF) shunt malfunctions in adults.

METHODS

We present a retrospective series of adult patients who underwent CSF shunt placement between 2000 and 2013 with Sophysa SM8.

RESULTS

In total, 599 patients (329 males and 270 females) were included. The mean age at surgery was 64.15 years (19-90) (SD 16.17; median 68.0). The causes of hydrocephalus were normal pressure hydrocephalus (49%), traumatic hemorrhages (26.5%), tumors (15.7%), cerebral aqueduct stenoses (3%), and arachnoid cysts (2%). The mean follow-up was 3.9 years (0-16) (SD 4.10; median 3 years). The rate of complications was 22.04% (132 of 599). Most frequent causes of complications were disconnection (25%), migration (12.9%), overdrainage (9.1%), and proximal obstruction (6.8%). In 17 cases (12.9%), no failure was diagnosed during revision. Seven infections (5.3%) were reported. The mean delay for the first revision was 1.70 years (0-13.93) (SD 2.67, median 0.35). The risk of shunt failure was 36% at 10 years. Seventeen percent of revisions occurred during the first year after shunt placement.

CONCLUSION

Disconnections are a very frequent complication of Sophysa SM8 valve. They are related to the 2-connector system of this valve. Based on these results, we recommend using 1-piece valves.

Magnetic resonance imaging-related programmable ventriculoperitoneal shunt valve setting changes occur often

PURPOSE

Patients with programmable ventriculoperitoneal (VP) shunt valves undergo multiple skull radiographs to evaluate for setting changes resulting from MRI. Our purpose was to determine the rates of inadvertent, MRI-related, programmable VP shunt valve setting changes.

MATERIALS AND METHODS

In this retrospective cohort with a study period of January 2015-December 2018, we reviewed the pre- and post-MRI skull radiographs of patients with programmable VP shunts and collected the following data: Demographics, commercial type of the valve used, magnetic field strength of the MRI device used, and whether a setting change occurred. We used the chi-square test to identify variables associated with valve setting change.

RESULTS

We identified 210 MRI exposure events in 156 patients, and an MRI-related valve setting change rate of 56.7%. The setting change rate was significantly higher with higher magnetic field strength (p = 0.03), and with Medtronic Strata™ valves compared to Codman Hakim™ valves (p < 0.0001).

CONCLUSION

Inadvertent, MRI-related shunt valve setting changes are frequent with valves that lack a locking mechanism. Therefore, we suggest that when feasible, the clinicians could opt to manually reprogram the valves after the MRI to the preferred setting without the need for pre- and post-MRI radiographs. We believe that this protocol modification could help reduce ionizing radiation exposure and cost. Manufacturers may consider incorporating locking mechanisms into the design of such devices in order to reduce the unintended setting change rates.

Preoperative risk and postoperative outcome from subdural fluid collections in African infants with postinfectious hydrocephalus

OBJECTIVE

This study investigated the incidence of postoperative subdural collections in a cohort of African infants with postinfectious hydrocephalus. The authors sought to identify preoperative factors associated with increased risk of development of subdural collections and to characterize associations between subdural collections and postoperative outcomes.

METHODS

The study was a post hoc analysis of a randomized controlled trial at a single center in Mbale, Uganda, involving infants (age < 180 days) with postinfectious hydrocephalus randomized to receive either an endoscopic third ventriculostomy plus choroid plexus cauterization or a ventriculoperitoneal shunt. Patients underwent assessment with the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III; sometimes referred to as BSID-III) and CT scans preoperatively and then at 6, 12, and 24 months postoperatively. Volumes of brain, CSF, and subdural fluid were calculated, and z-scores from the median were determined from normative curves for CSF accumulation and brain growth. Linear and logistic regression models were used to characterize the association between preoperative CSF volume and the postoperative presence and size of subdural collection 6 and 12 months after surgery. Linear regression and smoothing spline ANOVA were used to describe the relationship between subdural fluid volume and cognitive scores. Causal mediation analysis distinguished between the direct and indirect effects of the presence of a subdural collection on cognitive scores.

RESULTS

Subdural collections were more common in shunt-treated patients and those with larger preoperative CSF volumes. Subdural fluid volumes were linearly related to preoperative CSF volumes. In terms of outcomes, the Bayley-III cognitive score was linearly related to subdural fluid volume. The distribution of cognitive scores was significantly different for patients with and those without subdural collections from 11 to 24 months of age. The presence of a subdural collection was associated with lower cognitive scores and smaller brain volume 12 months after surgery. Causal mediation analysis demonstrated evidence supporting both a direct (76%) and indirect (24%) effect (through brain volume) of subdural collections on cognitive scores.

CONCLUSIONS

Larger preoperative CSF volume and shunt surgery were found to be risk factors for postoperative subdural collection. The size and presence of a subdural collection were negatively associated with cognitive outcomes and brain volume 12 months after surgery. These results have suggested that preoperative CSF volumes could be used for risk stratification for treatment decision-making and that future clinical trials of alternative shunt technologies to reduce overdrainage should be considered.

Mechanical complications of cerebrospinal fluid shunt. Differences between adult and pediatric populations: myths or reality?

OBJECTIVE

Shunt malfunctions seem more frequent in children (44 to 81%) than in adults (18 to 29%). Because of discrepancies between studies, it is not possible to affirm this disparity. The objective was to verify whether the incidence of cerebrospinal fluid (CSF) shunt malfunctions is higher in children than adults.

METHODS

We present a retrospective series of child and adult patients who underwent CSF shunt placement between 2000 and 2013 with a Sophysa SM8® valve.

RESULTS

599 adults and 98 children (sex ratio 1.28) underwent CSF shunt placement. Age at first surgery ranged between 1 day of life and 90 years (mean of 55.8 years, SD 25.8, median 64.8 years). The mean follow-up was 4 years (SD 4.264, 0-16; median 3 years). The cumulative complication rate was 25.5% (178/697). Mechanical complications were disconnection (25.1%), migration (11.8%), intracranial catheter obstruction (8.9%) and malposition (8.4%). The mean delay for the first revision was 1.90 years (0-13.9), (SD 2.73, median 0.5). The probability of shunt failure was 65% at 10 years in the child group and 36% at 10 years in the adult group. Moreover, in the child group, 33% of revisions occurred during the first year after shunt placement versus 17% in the adult group. Thus, the probability of shunt failure was higher in children than in adults (log-rank test, p < 0.001).

CONCLUSIONS

This is the first retrospective study, comparing children and adults undergoing CSF shunt using the same valve, able to confirm the higher rate of complications in children.

In vitro testing of explanted shunt valves in hydrocephalic patients with suspected valve malfunction

Diagnosis of symptomatic valve malfunction in hydrocephalic patients treated with VP-Shunt (VPS) might be difficult. Clinical symptoms such as headache or nausea are nonspecific, hence cerebrospinal fluid (CSF) over- or underdrainage can only be suspected but not proven. Knowledge concerning valve malfunction is still limited. We aim to provide data on the flow characteristics of explanted shunt valves in patients with suspected valve malfunction. An in vitro shunt laboratory setup was used to analyze the explanted valves under conditions similar to those in an implanted VPS. The differential pressure (DP) of the valve was adjusted stepwise to 20, 10, 6, and 4 cmH₂O. The flow rate of the explanted and the regular flow rate of an identical reference valve were evaluated at the respective DPs. Twelve valves of different types (Codman CertasPlus valve n = 3, Miethke Shuntassistant valve n = 4, Codman Hakim programmable valve n = 3, DP component of Miethke proGAV 2.0 valve n = 2) from eight hydrocephalic patients (four male), in whom valve malfunction was assumed between 2016 and 2017, were replaced with a new valve. Four patients suffered from idiopathic normal pressure (iNPH), three patients from malresorptive and one patient from obstructive hydrocephalus. Post-hoc analysis revealed a significant difference (p < 0.001) of the flow rate between each explanted valve and their corresponding reference valve, at each DP. In all patients, significant alterations of flow rates were demonstrated, verifying a valve malfunction, which could not be objectified by the diagnostic tools used in the clinical routine. In cases with obscure clinical VPS insufficiency, valve deficiency should be considered.

The Correlative Factors and Probable Mechanism of Epidural Fluid Collection After Cranioplasty

OBJECTIVE

Epidural fluid collection (EFC) is one of the postoperative complications of cranioplasty and is easily ignored. Not only the predictive factors of EFC formation are unknown, the pathologic mechanisms are also unknown. We determined to analyze the predictive factors and the mechanism of EFC formation.

METHODS

A total of 340 patients underwent cranioplasty were retrospectively analyzed in this study. A series of factors were compared in the EFC and none-EFC groups and farther compared in the progress epidural fluid collection (PEFC) and none-PEFC subgroups to determine the predictive factors. The t test, χ test, and logistic regression analysis were used in statistical analysis.

RESULTS

The rate of EFC formation was 34.41%, and the size of skull defect, preoperative volume of collapse, intraoperative dura suspending, a pre- or intraoperative ventriculoperitoneal shunt (V-P shunt), and an postoperative air bubble in epidural space were predictive factors for EFC formation. Furthermore, the incidence of PEFC was 10.29%, the size of skull defects and intraoperative dura suspending were predictive factors for PEFC formation. The protein ratio and lactate dehydrogenase (LDH) ratio of effusion to serum were >0.5 and 0.6, respectively. There was no adverse prognosis.

CONCLUSIONS

Although EFC can be treated with conservative therapy, we need to emphasize EFC incidence and development. As neurosurgeons, it is necessary to analyze the preoperative predictive factors of EFC, pay attention to the intraoperative details such as dura suspending to prevent PEFC formation, and the early intervention should be performed in the postoperative.

Ventriculoperitoneal shunt complications in an adult population: A comparison of various shunt designs to prevent overdrainage

Background:

Overdrainage after cerebrospinal fluid diversion remains a significant morbidity. The hydrostatic, gravitational force in the upright position can aggravate this. Siphon control (SC) mechanisms, as well as programmable and flow regulating devices, were developed to counteract this. However, limited studies have evaluated their safety and efficacy. In this study, direct comparisons of the complication rates between siphon control (SC) and non-SC (NSC), fixed versus programmable, and flow- versus pressure regulating valves are undertaken.

Methods:

A retrospective chart review was performed over all shunt implantations from January 2011 to December 2016 within the Houston Methodist Hospital system. Complication rates within 6 months of the operative date, including infection, subdural hematoma, malfunction, and any other shunt-related complication, were analyzed via Fisher’s exact test, with P < 0.05 regarded as significant. Subgroup analyses based on diagnoses – normal pressure hydrocephalus (HCP), pseudotumor cerebri, or other HCP – were also performed.

Results:

The overall shunt-related complication rate in this study was 19%. Overall rates of infection, shunt failure, and readmission within 180 days were 3%, 11%, and 34%, respectively. No difference was seen between SC and NSC groups in any complication rate overall or on subgroup analyses. When comparing fixed versus programmable and flow- versus pressure-regulating valves, the latter in each analysis had significantly lower malfunction and total complication rates.

Conclusions:

Programmable and pressure regulating devices may lead to lower shunt malfunction and total complication rates. Proper patient selection should guide valve choice. Future prospective studies may further elucidate the difference in complication rates between these various shunt designs.

Programmable valve breakage in shunt systems of children with posthemorrhagic hydrocephalus after minor head trauma-a case series

PURPOSE

We report five rare cases of programmable valve breakage (Codman Hakim-Medos valve) in shunt systems of children with posthemorrhagic hydrocephalus. Only four similar studies have been published in the current literature.

METHODS

Between 2013 and 2018, five children with posthemorrhagic hydrocephalus were admitted to the pediatric department. All patients had a history of slight blows to the head in a minor trauma and follow up MRI scans. After initial clinical examination, cranial computed tomography (CT) and X-ray were conducted.

RESULTS

In all cases, pumping the reservoir resulted in very slow refilling. The cranial CT in one patient showed slit ventricles confirming the suspicion of overdrainage, the other cases a slight enhancement of the hydrocephalus. In lateral X-rays of the skull in comparison to the first X-ray control of the shunt valve, the pressure control chamber could be seen dislocated in the inferior part of the reservoir in all cases. Surgery revealed that the shunt valve was broken. The pressure control chamber had dropped to the bottom of the reservoir. After implantation of a new shunt valve, the symptoms resolved completely in all five children. Overall this complication occurred in 4.3% (5 of 85 implanted Codman Hakim-Medos valve) of all children necessitating ventriculoperitoneal shunt implantation between January 2013 and December 2018.

CONCLUSION

The well-accepted Codman Hakim-Medos programmable valve is part of a tube-system, which is designed to offer the possibility of a reliable and precise treatment of hydrocephalus. Various mechanical and non-mechanical complications of shunt systems have been reported. Valve breakage is a very rare condition, often missed, and must be kept in mind when trauma and prior MRI scan are reported.

An investigation of factors associated with the development of postoperative bone flap infection following decompressive craniectomy and subsequent cranioplasty

OBJECTIVE

After a decompressive craniectomy (DC), a cranioplasty (CP) is often performed in order to improve neurosurgical outcome and cerebral blood circulation. But even though the performance of a CP subsequent to a DC has become routine medical practice, patients can in fact develop many complications from the surgery that could prolong hospitalization and lead to unfavorable prognoses. This study investigates one of the most frequent complications, bone flap infection, in order to identify prognostic factors of its development.

PATIENTS AND METHODS

In this single-center study, we have retrospectively examined 329 CPs performed between 2002 and 2017. Multiple categorical and metric parameters (e.g., timing of CP, bone flap material, specific laboratory signs of infection and reason for DC) were analyzed applying unadjusted and multivariable testing.

RESULTS

Bone flap infection occurred in 24 patients (7.3%). A CP performed more than six months after a DC is associated with a significantly increased risk of infection (OR = 0.308 [0.118; 0.803], p = 0.016). However, with CPs performed after twelve months, the incidence decreases, but without provable statistical impact. In addition, bone flap infection is strongly related to the neurological outcome and the material used for the skull implant, with the use of synthetic bone flaps leading to a marked increase in the rate of infection (p < 0.001).

CONCLUSIONS

This study supports the hypothesis that the risk of infection is higher the longer the elapsed time between DC and CP, especially if more than six months. Based on our results, the best DC-CP time frame for keeping the infection rate low is performing the CP within the first six months after the DC. In the event that the CP cannot be performed within the first six months, a CP performed twelve months or more after the DC seems to have a favorable outcome as well.

Efficacy and safety of programmable compared with fixed anti-siphon devices for treating idiopathic normal-pressure hydrocephalus (iNPH) in adults - SYGRAVA: study protocol for a randomized trial

BACKGROUND

Idiopathic normal-pressure hydrocephalus (iNPH) is a distinct form of dementia, characterized by gait ataxia, cognitive impairment and urinary incontinence. In contrast to all other causes of dementia (e.g., Alzheimer-type and others), ventriculoperitoneal (VP) shunt surgery may offer a curative treatment option to patients. While being a rather low-risk type of surgery, it may cause significant over- or underdrainage complications (e.g., headaches, dizziness, vomiting, intracerebral bleeding, etc.) during posture change. Anti-siphon devices (ASDs) are a group of technically different additional valves used in shunt surgery. They are designed to maintain intraventricular pressure within a normal physiological range regardless of patient position. Fixed ASDs proved to substantially lower the rate of overdrainage complications. No significant differences, however, were noted regarding underdrainage complications. Technical successors of fixed ASDs are programmable ASDs. The aim of this study is to evaluate whether programmable ASDs compared to fixed ASDs are able to avoid both over- and underdrainage complications.

METHODS/DESIGN

In this investigator-initiated, multicenter randomized trial, 306 patients are planned to be recruited. Male and female patients aged ≥18 years with iNPH who are eligible for VP shunt surgery and meet all other entry criteria can participate. Patients will be randomized in a balanced 1: 1 fashion to a VP shunt with a programmable valve either supplemented with a fixed ASD, or a programmable ASD. Patients will be followed-up 3, 6 and, on an optional basis, 12 months after surgery. The primary outcome measure is the cumulative incidence of over- or underdrainage 6 months post surgery, as defined by clinical and imaging parameters.

DISCUSSION

SYGRAVA is the first randomized trial to determine whether programmable ASDs reduce complications of drainage compared to fixed ASDs in patients with iNPH. The results of this study may contribute to health-technology assessment of different valve systems used for VP-shunt surgery, and determination of the future standard of care.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number: ISRCTN13838310 . Registered on 10 November 2016.

Subdural hematomas in 1846 patients with shunted idiopathic normal pressure hydrocephalus: treatment and long-term survival

OBJECTIVE Subdural hematoma (SDH) is the most common serious adverse event in patients with shunts. Adjustable shunts are used with increasing frequency and make it possible to noninvasively treat postoperative SDH. The objective of this study was to describe the prevalence and treatment preferences of SDHs, based on fixed or adjustable shunt valves, in a national cohort of patients with shunted idiopathic normal pressure hydrocephalus (iNPH), as well as to evaluate the effect of SDH and treatment on long-term survival. METHODS Patients with iNPH who received a CSF shunt in Sweden from 2004 to 2015 were included in a prospective quality registry (n = 1846) and followed regarding SDH, its treatment, and mortality. The treatment of SDH was categorized into surgery, opening pressure adjustments, or no treatment. RESULTS During the study period, the proportion of adjustable shunts increased from 75% to 95%. Ten percent (n = 184) of the patients developed an SDH. In 103 patients, treatment was solely opening pressure adjustment. Surgical treatment was used in 66 cases (36%), and 15 (8%) received no treatment. In patients with fixed shunt valves, 90% (n = 17) of SDHs were treated surgically compared with 30% (n = 49) in patients with adjustable shunts (p < 0.001). There was no difference in long-term patient survival between the SDH and non-SDH groups or between different treatments. CONCLUSIONS SDH remains a common complication after shunt surgery, but adjustable shunts reduced the need for surgical interventions. SDH and treatment did not significantly affect survival in this patient group, thus the noninvasive treatment offered by adjustable shunts considerably reduces the level of severity for this common adverse event.

Use of programmable versus nonprogrammable shunts in the management of normal pressure hydrocephalus: A multicenter retrospective study with cost-benefit analysis in Turkey

Ventriculoperitoneal shunt systems that are used in the treatment of normal pressure hydrocephalus are often associated with drainage problems. Adjustable shunt systems can prevent or treat these problems, but they may be expensive. The aim of our study is to compare the complications and total cost of several shunt systems.Patients with normal pressure hydrocephalus who underwent ventriculoperitoneal shunting between 2011 and 2016 were included in the study. The study involves patient consent and the informed consent was given. Complications and the average cost per person were compared between patients with adjustable and nonadjustable shunts. Shunt prices, surgical complications, and revision costs were taken into account to calculate the average cost.Of the 110 patients who were evaluated, 80 had a nonadjustable shunt and 30 had an adjustable shunt. In the group with adjustable shunts, the rates of subdural effusion and hematoma were 19.73% and 3.29%, respectively. In the group with nonadjustable shunts, these rates were 22.75% and 13.75%, respectively. One patient in the adjustable group underwent surgery for subdural hematoma, while 8 patients in the nonadjustable group underwent the same surgery. Ten patients required surgical intervention for subdural effusion and existing shunt systems in these patients were replaced by an adjustable shunt system. When these additional costs were factored into the analysis, the difference in cost between the shunt systems was reduced from 600 United States dollars (USD) to 111 USD.When the complications and additional costs that arise during surgical treatment of normal pressure hydrocephalus were considered, the price difference between adjustable and nonadjustable shunt systems was estimated to be much lower.

Hydrocephalus treatment in children: long-term outcome in 975 consecutive patients

OBJECTIVE Hydrocephalus remains one of the more common pathologies managed in pediatric neurosurgical units. Endoscopic third ventriculostomy (ETV) has an advantage over ventriculoperitoneal shunting as it enables patients to remain device free. Multiple shunt devices with various valve designs exist, with no one valve proven to be superior to another. The aim of this study was to describe the management of hydrocephalus and its long-term outcome. METHODS The authors retrospectively reviewed the medical records of all patients who had been treated for hydrocephalus at the Hôpital Necker-Enfants Malades in the period from 1985 to 1995. RESULTS Nine hundred seventy-five children had been treated for hydrocephalus. The mean follow-up was 11 ± 7.4 years (mean ± standard deviation). The most common cause of hydrocephalus was tumor related (32.3%), followed by malformative (24.5%) and inflammatory (20.9%) causes. Two hundred eighty patients underwent ETV as the first-line treatment. The procedure was effective in controlling hydrocephalus due to posterior fossa tumors and aqueductal stenosis. Six hundred ninety-five children had initial shunt insertion, with the majority receiving an Orbis-Sigma valve (OSV). The overall OSV shunt survival was 70% at 1 year, 58% at 10 years, and 49% at 20 years. The most common cause for mechanical shunt failure was obstruction (50.7%). Overall shunt survival was statistically different between the OSV and the differential-pressure valve (p = 0.009). CONCLUSIONS Endoscopic third ventriculostomy is effective in the management of childhood hydrocephalus. Its success is directly related to the underlying pathology. In the long term, the OSV has significantly higher event-free shunt survival than the classic differential-pressure valve systems.

Ventricular catheter development: past, present, and future

Cerebrospinal fluid diversion via ventricular shunting is the prevailing contemporary treatment for hydrocephalus. The CSF shunt appeared in its current form in the 1950s, and modern CSF shunts are the result of 6 decades of significant progress in neurosurgery and biomedical engineering. However, despite revolutionary advances in material science, computational design optimization, manufacturing, and sensors, the ventricular catheter (VC) component of CSF shunts today remains largely unchanged in its functionality and capabilities from its original design, even though VC obstruction remains a primary cause of shunt failure. The objective of this paper is to investigate the history of VCs, including successful and failed alterations in mechanical design and material composition, to better understand the challenges that hinder development of a more effective design.

Ventricular Shunts

Ventricular shunts are mechanical devices used in the treatment of hydrocephalus, by means of which cerebrospinal fluid (CSF) is diverted from the ventricles to other low-pressure body cavities. Over the last 50 years, mechanical shunting has become the cornerstone for the treatment of hydrocephalus with shunt valves evolving from simple differential valves to complex programmable valves. The chief complications of ventricular shunting include obstruction, infections, and overdrainage causing subdural hematomas and slit-ventricle syndrome. As the number of commercially available valve designs continues to grow, each new generation aims at reducing the likelihood of complications, especially those resulting from overdrainage. Several studies aimed at establishing the superiority of any valve design have been conducted. All have highlighted the advantages and shortcomings of most models without conclusively providing evidence for choosing one over another. As a result, choices still rest on individual and institutional preferences.

Long-term survival rates of gravity-assisted, adjustable differential pressure valves in infants with hydrocephalus

OBJECTIVE The use of adjustable differential pressure valves with gravity-assisted units in shunt therapy of children with hydrocephalus was reported to be feasible and promising as a way to avoid chronic overdrainage. In this single-center study, the authors' experiences in infants, who have higher rates of shunt complications, are presented. METHODS All data were collected from a cohort of infants (93 patients [37 girls and 56 boys], less than 1 year of age [mean age 4.1 ± 3.1 months]) who received their first adjustable pressure hydrocephalus shunt as either a primary or secondary implant between May 2007 and April 2012. Rates of valve and shunt failure were recorded for a total of 85 months until the end of the observation period in May 2014. RESULTS During a follow-up of 54.2 ± 15.9 months (range 26-85 months), the Kaplan-Meier rate of shunt survival was 69.2% at 1 year and 34.1% at 85 months; the Kaplan-Meier rate of valve survival was 77.8% at 1 year and 56% at 85 months. Survival rates of the shunt were significantly inferior if the patients had previous shunt surgery. During follow-up, 44 valves were exchanged in cases of infection (n = 19), occlusion (n = 14), dysfunction of the adjustment unit (n = 10), or to change the gravitational unit (n = 1). CONCLUSIONS Although a higher shunt complication rate is observed in infant populations compared with older children, reasonable survival rates demonstrate the feasibility of using this sophisticated valve technology. The gravitational unit of this valve is well tolerated and its adjustability offers the flexible application of opening pressure in an unpredictable cohort of patients. This may adequately address overdrainage-related complications from early in treatment.

Practice guideline: Idiopathic normal pressure hydrocephalus: Response to shunting and predictors of response: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

We evaluated evidence for utility of shunting in idiopathic normal pressure hydrocephalus (iNPH) and for predictors of shunting effectiveness.

METHODS

We identified and classified relevant published studies according to 2004 and 2011 American Academy of Neurology methodology.

RESULTS

Of 21 articles, we identified 3 Class I articles.

CONCLUSIONS

Shunting is possibly effective in iNPH (96% chance subjective improvement, 83% chance improvement on timed walk test at 6 months) (3 Class III). Serious adverse event risk was 11% (1 Class III). Predictors of success included elevated Ro (1 Class I, multiple Class II), impaired cerebral blood flow reactivity to acetazolamide (by SPECT) (1 Class I), and positive response to either external lumbar drainage (1 Class III) or repeated lumbar punctures. Age may not be a prognostic factor (1 Class II). Data are insufficient to judge efficacy of radionuclide cisternography or aqueductal flow measurement by MRI.

RECOMMENDATIONS

Clinicians may choose to offer shunting for subjective iNPH symptoms and gait (Level C). Because of significant adverse event risk, risks and benefits should be carefully weighed (Level B). Clinicians should inform patients with iNPH with elevated Ro and their families that they have an increased chance of responding to shunting compared with those without such elevation (Level B). Clinicians may counsel patients with iNPH and their families that (1) positive response to external lumbar drainage or to repeated lumbar punctures increases the chance of response to shunting, and (2) increasing age does not decrease the chance of shunting being successful (both Level C).

Spectral analysis of intracranial pressure: Is it helpful in the assessment of shunt functioning in-vivo?

OBJECTIVE

Shunt failure is common in hydrocephalic patients. The cerebrospinal fluid (CSF) infusion test enables the assessment of CSF absorption capacity, which is represented by the resistance to CSF outflow (ROUT) However, shunt failure may not only affect the CSF absorption capacity but also the intracranial compliance or compensatory properties. Spectral analysis of the ICP signal obtained during the infusion test may enable the comprehensive assessment of the overall deterioration caused by shunt failure.

MATERIAL AND METHODS

A total of 121 hydrocephalic shunted patients underwent the infusion test with continuous intracranial pressure (ICP) and arterial blood pressure (ABP) recording. The maximum amplitudes of three major frequency bandwidths (0.2-2.6, 2.6-4.0 and 4.0-15 Hz, respectively) were calculated from the ICP. Statistical analyses were conducted to identify factors significantly associated with shunt failure, to construct an index (i.e., the shunt response parameter, SRP) for detecting shunt failure, and to define thresholds for ROUT and SRP.

RESULTS

The ROUT threshold for detecting shunt failure was 7.59 mmHg/ml/min, and this threshold showed an accuracy of 82.64%. All spectral parameters were found to be significantly associated with shunt patency (p<0.05). The SRP exhibited significantly better accuracy than ROUT in detecting shunt failure (91.74%).

CONCLUSION

The hydrodynamic assessment of shunted patients enhanced by spectral analysis during the infusion test detected shunt failure with high accuracy. Although further validation is needed, the SRP exhibited promising results.

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 ventriculoperitoneal shunting in patients with neoplasms of the central nervous system: An analysis of 59 cases

Approximately 1-5% of patients with cerebral metastasis and ~40% of patients with primary brain tumors suffer from hydrocephalus. These patients often exhibit a poor prognosis. The aim of the present study was to reassess the validity of ventriculoperitoneal shunting (VPS) with the assistance of the general surgeon in oncological patients. A total of 59 patients underwent first-time VPS at the Beth Israel Deaconess Medical Center (Boston, USA) between 2004 and 2012; 40 patients had hydrocephalus from brain metastasis and 19 from primary tumors. The analyzed independent variables included demographics, body mass index, past medical history, clinical presentation, indication for surgery, Karnofsky performance status (KPS) score and surgical technique; the dependent variables were postoperative symptoms and occurrence, cause and time of shunt failure. The outcomes were analyzed with the t-test and Kaplan-Meier estimates for shunt survival. The mean age of the patients was 57.2 years and the mean operative time was 50.4 min. Symptomatic palliation was achieved in 93% of the cases; patients with severe symptoms, such as debilitating headaches, nausea and vomiting, benefited significantly from VPS. The mean follow-up time was 6.3 months; complications occurred in only 7 patients (11.8%) during follow-up: 2 in the proximal shunt (1 infection and 1 obstruction), both requiring revision, 1 infection in the distal catheter requiring shunt removal, 2 cases of intracerebral bleeding that were monitored with computed tomography scans, 1 wound infection treated with antibiotics and 1 valve complication that required temporary revision. The initial and 3-month KPS scores were 65±16.4 and 75±16.0, respectively. The mean overall shunt survival was 6.4 months (range, 1.0 day-76.0 months) from the placement of the VP shunt. At 3 months after VPS, 93.5% of the patients remained alive with functioning shunts and at 1 year 87% of the shunts were still functioning. In conclusion, VPS remains a valid option for cancer patients with low KPS, as it improves the quality of life in such patients, even in the setting of previous infection, hemorrhage, or leptomeningeal disease, since shunt patency outlasts the overall survival of nearly all patients.

Evidences in the treatment of idiopathic normal pressure hydrocephalus

INTRODUCTION

idiopathic normal pressure hydrocephalus (INPH) is characterized by gait apraxia, cognitive dysfunction and urinary incontinence. There are two main treatment options: ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV). However, there are doubts about which modality is superior and what type of valve should be applied. We are summarizing the current evidence in INPH treatment.

METHODS

an electronic search of the literature was conducted on the Medline, Embase, Scielo and Lilacs databases from 1966 to the present to obtain data published about INPH treatment.

RESULTS

the treatment is based on three pillars: conservative, ETV and VPS. The conservative option has fallen into disuse after various studies showing good results after surgical intervention. ETV is an acceptable mode of treatment, but the superiority of VPS has made the latter the gold standard.

CONCLUSION

well-designed studies with a high level of appropriate evidence are still scarce, but the current gold standard for treatment of INPH is conducted using VPS.

Radiographic evaluation of pediatric cerebrospinal fluid shunt malfunction in the emergency setting

Children with ventricular cerebrospinal fluid shunts for treatment of hydrocephalus require frequent evaluation for potential shunt malfunction. Current practice relies heavily on neuroimaging, particularly cranial computed tomography, which repeatedly exposes children to ionizing radiation. Rapid cranial magnetic resonance imaging is a new radiation-sparing alternative to CT for evaluation of potential shunt malfunction. We review the diagnostic test performance, radiation exposure, advantages, and limitations of the major neuroimaging modalities available to providers caring for children with possible shunt malfunction in the emergent setting.

Early cranioplasty vs. late cranioplasty for the treatment of cranial defect: A systematic review

BACKGROUND

Cranioplasty is considered as a routine procedure in everyday neurosurgical practice for the patient with cranial defect, however, there is no established consensus on optimal surgical timing.

OBJECTIVE

To compare the effect of early cranioplasty (1-3 months after DC) and late cranioplasty (3-6 months after DC) on the complications and recovery of neurological function in the management of patients who received decompressive craniotomy.

METHODS

In this paper, the authors report a systematic review and meta-analysis of operative time, complications and neurological function outcomes on different timing of cranioplasty. Randomized or non-randomized controlled trials of early cranioplasty and late cranioplasty surgery were considered for inclusion.

RESULTS

Nine published reports of eligible studies involving 1209 participants meet the inclusion criteria. Compared with late cranioplasty, early cranioplasty had no significant difference in overall complications [RR=1.14, 95%CI (0.83, 1.55), p>0.05], infection rates [RR=0.87, 95%CI (0.47, 1.61), p>0.05], intracranial hematoma [RR=1.09, 95%CI (0.53, 2.25), p>0.05]; subdural fluid collection [RR=0.47, 95%CI (0.15, 1.41), p>0.05]. However, early CP significantly reduced the duration of cranioplasty [mean difference=-13.46, 95%CI (-21.26, 5.67), p<0.05]. The postoperative hydrocephalus rates were significant higher in the early cranioplasty group [RR=2.67, 95%CI (1.24, 5.73), p<0.05].

CONCLUSION

Early CP can only reduce the duration of operation, but cannot reduce the complications of patients and even increase the risk of hydrocephalus. More evidence from advanced multi-center studies is needed to provide illumination for the timing selection of CP surgery.

Intracranial pressure monitoring in pediatric and adult patients with hydrocephalus and tentative shunt failure: a single-center experience over 10 years in 146 patients

OBJECT In patients with hydrocephalus and shunts, lasting symptoms such as headache and dizziness may be indicative of shunt failure, which may necessitate shunt revision. In cases of doubt, the authors monitor intracranial pressure (ICP) to determine the presence of over- or underdrainage of CSF to tailor management. In this study, the authors reviewed their experience of ICP monitoring in shunt failure. The aims of the study were to identify the complications and impact of ICP monitoring, as well as to determine the mean ICP and characteristics of the cardiac-induced ICP waves in pediatric versus adult over- and underdrainage. METHODS The study population included all pediatric and adult patients with hydrocephalus and shunts undergoing diagnostic ICP monitoring for tentative shunt failure during the 10-year period from 2002 to 2011. The patients were allocated into 3 groups depending on how they were managed following ICP monitoring: no drainage failure, overdrainage, or underdrainage. While patients with no drainage failure were managed conservatively without further actions, over- or underdrainage cases were managed with shunt revision or shunt valve adjustment. The ICP and ICP wave scores were determined from the continuous ICP waveforms. RESULTS The study population included 71 pediatric and 75 adult patients. There were no major complications related to ICP monitoring, but 1 patient was treated for a postoperative superficial wound infection and another experienced a minor bleed at the tip of the ICP sensor. Following ICP monitoring, shunt revision was performed in 74 (51%) of 146 patients, while valve adjustment was conducted in 17 (12%) and conservative measures without any actions in 55 (38%). Overdrainage was characterized by a higher percentage of episodes with negative mean ICP less than -5 to -10 mm Hg. The ICP wave scores, in particular the mean ICP wave amplitude (MWA), best differentiated underdrainage. Neither mean ICP nor MWA levels showed any significant association with age. CONCLUSIONS In this cohort of pediatric and adult patients with hydrocephalus and tentative shunt failure, the risk of ICP monitoring was very low, and helped the authors avoid shunt revision in 49% of the patients. Mean ICP best differentiated overdrainage, which was characterized by a higher percentage of episodes with negative mean ICP less than -5 to -10 mm Hg. Underdrainage was best characterized by elevated MWA values, indicative of impaired intracranial compliance.

Intracranial pressure in hydrocephalus: impact of shunt adjustments and body positions

BACKGROUND

The association between intracranial pressure (ICP) and different shunt valve opening pressures in relation to body positions is fundamental for understanding the physiological function of the shunt.

OBJECTIVE

To analyse the ICP and ICP wave amplitude (AMP) at different shunt settings and body positions in patients with hydrocephalus.

METHODS

In this prospective study 15 patients with communicating hydrocephalus were implanted with a ligated adjustable ventriculoperitoneal shunt. They also received a portable intraparenchymatous ICP-monitoring device. Postoperative ICP and AMP were recorded with the patients in three different body positions (supine, sitting and walking) and with the shunt ligated and open at high, medium and low valve settings. In each patient 12 10 min segments were coded, blinded and analysed for mean ICP and mean AMP using an automated computer algorithm.

RESULTS

Mean ICP and mean AMP were lower at all three valve settings compared with the ligated shunt state (p<0.001). Overall, when compared with the supine position, mean ICP was 11.5±1.1 (mean±SD) mm Hg lower when sitting and 10.5±1.1 mm Hg lower when walking (p<0.001). Mean ICP was overall 1.1 mm Hg higher (p=0.042) when walking compared with sitting. The maximal adjustability difference (highest vs lowest valve setting) was 4.4 mm Hg.

CONCLUSIONS

Changing from a supine to an upright position reduced ICP while AMP only increased at trend level. Lowering of the shunt valve opening pressure decreased ICP and AMP but the difference in mean ICP in vivo between the highest and lowest opening pressures was less than half that previously observed in vitro.

Is there an ideal shunt? A panoramic view of 110 years in CSF diversions and shunt systems used for the treatment of hydrocephalus: from historical events to current trends

OBJECT

The goal of this study is to evaluate whether an "ideal shunt" exists.

METHODS

This is a retrospective analysis based on original papers in the field of Hydrocephalus and Shunts. Patients of all age groups, who had hydrocephalus, and underwent some form of CSF diversion were included. The study has been divided into four stages: from 1900 to 1949, 1950 to 1974, 1975 to 1999, and from 2000 to 2010.

RESULTS

In stage 1 (historical era): Saphenous vein grafts, rubber conduits, and other materials were used in CSF diversions. In 1949, the first implantable shunt tube was developed by Nulsen. In stage 2 (experimental stage): the Holter valve was developed. Newer innovations were developed in relation to the ventriculo-atrial shunt, which was the preferred CSF diversion. In stage 3 (developmental stage), a large number of different design shunt systems were developed, with the aim of reducing complications. The ventriculo-peritoneal shunt had become the preferred CSF diversion. Also, the programmable valve was born. In stage 4 (era of programmable valve, there is a preference for the use of programmable shunt systems. However, shunt failure rate at 1 year being around 25 to 40%, and shunt survival at 1 and 2 years are 50-70 and 47-53% in most series.

CONCLUSION

Every shunt is an ideal shunt provided the choice of the shunt used should be made by the matching performance of the shunt system to the altered profile of CSF dynamics of a given patient. The most important factor being the opening pressure.

A randomized controlled dual-center trial on shunt complications in idiopathic normal-pressure hydrocephalus treated with gradually reduced or “fixed” pressure valve settings

Object

This study was undertaken to investigate whether a gradual reduction of the valve setting (opening pressure) decreases the complication rate in patients with idiopathic normal-pressure hydrocephalus (iNPH) treated with a ventriculoperitoneal (VP) shunt.

Methods

In this prospective double-blinded, randomized, controlled, dual-center study, a VP shunt with an adjustable valve was implanted in 68 patients with iNPH, randomized into two groups. In one group (the 20–4 group) the valve setting was initially set to 20 cm H2O and gradually reduced to 4 cm H2O over the course of the 6-month study period. In the other group (the 12 group), the valve was kept at a medium pressure setting of 12 cm H2O during the whole study period. The time to and type of complications (hematoma, infection, and mechanical problems) as well as overdrainage symptoms were recorded. Symptoms, signs, and outcome were assessed by means of the iNPH scale and the NPH grading scale.

Results

Six patients in the 20–4 group (22%) and 7 patients in the 12 group (23%) experienced a shunt complication; 9 had subdural hematomas, 3 mechanical obstructions, and 1 infection (no significant difference between groups). The frequency of overdrainage symptoms was significantly higher for a valve setting ≤ 12 cm H2O compared with a setting > 12 cm H2O. The 20–4 group had a higher improvement rate (88%) than the 12 group (62%) (p = 0.032). There was no significant relationship between complications and body mass index, the use of an antisiphon device, or the use of anticoagulants.

Conclusions

Gradual lowering of the valve setting to a mean of 7 cm H2O led to the same rate of shunt complications and overdrainage symptoms as a fixed valve setting at a mean of 13 cm H2O but was associated with a significantly better outcome.

Adjustments in gravitational valves for the treatment of childhood hydrocephalus-a retrospective survey

OBJECTIVE

Debatable disadvantages of preset differential pressure valves in treating pediatric hydrocephalus are the inability to treat over- and underdrainage after implantation without further surgery. This survey aims to retrospectively determine whether adjustments were performed and effectively used for the individual adaptation of CSF drainage from the shunted patients' and families' perspective.

METHODS

In a series of 132 consecutive patients (59girls; 73boys, 0-29 years), families, caretakers, or the patients themselves were interviewed about their experiences after using the proGAV (Miethke-Aesculap, Germany) within a CSF-diverting shunt system. Thereby, the necessity and amounts of adjustments were evaluated. The subjective experiences of the adjustment process as well as the subsequent surgical interventions were documented with a follow-up period of 25.6 ± 9 months.

RESULTS

In 87.9 % of the cases, clinical symptoms improved subjectively after valve implantation. A total of 103 adjustments in 69 patients were performed. In 30 % of patients, more than one readjustment was done. As subjective experience, the adjustment process was described by 85 % of patients as painless or merely uncomfortable. Symptoms improved in 91 % in connection to a new pressure setting. During the entire follow-up period, 61 % of all patients remained free of surgery.

CONCLUSION

The recently used adjustable valves provide good clinical results and seem to lead to satisfactory treatment from the perspective of the affected patients or caretakers. Although a mechanical manipulation of the skin is necessary, the mechanism of the integrated adjustment unit was mostly well tolerated and allows for a noninvasive and MRI stable treatment of over- and underdrainage.

Programmable shunt valves for the treatment of hydrocephalus: a systematic review

OBJECTIVE

To evaluate the clinical effectiveness of programmable valves compared with non-programmable valves of hydrocephalus.

METHODS

In this paper, the authors report a systematic review and meta-analysis of complications and revision rate for programmable valves and non-programmable implantation. Randomized or non-randomized controlled trials of hydrocephalus treated by programmable and non-programmable valves were considered for inclusion.

RESULTS

Seven published reports of eligible studies involving 1702 participants meet the inclusion criteria. Compared with non-programmable, programmable valves had no significant difference in catheter-related complications [RR = 0.88, 95%CI (0.66,1.19), p = 0.10] and infection rate [RR = 1.25, 95%CI (0.92,1.69), p = 1.00]. There were significant differences in overall complications [RR = 0.80, 95%CI (0.67,0.96), p < 0.01], over-drainage or under-drainage complications [RR = 0.44, 95%CI (0.31,0.63), p < 0.01] and revision rate [RR = 0.56, 95%CI (0.45,0.69), p < 0.01] in favor of programmable valves.

CONCLUSION

Although the studies seem to demonstrate a small advantage for the programmable shunts, the probable bias and the difficulties in patient selection are too important to make a general conclusion.

Programming jammed Codman Hakim programmable valves: study of an explanted valve and successful programming in a patient

Malfunction of a Codman Hakim programmable valve due to jamming of its programmable component may necessitate shunt revision. The authors report a method for programming jammed Codman Hakim programmable valves by using a Strata II magnet and additional neodymium magnets. The programming method was derived after studying a jammed valve in the laboratory that was explanted from an 10-year-old boy with a history of fourth ventricle ependymoma. Programming the explanted valve with a Codman programmer failed, but rotating a Strata II magnet above the valve resulted in rotation of the spiral cam in the valve. It was found that the Strata II magnet could be used to program the jammed valve by rotating the magnet 90° or multiples of 90° above the valve. The strength of the magnetic field of the Strata II magnet was able to be increased by putting neodymium magnets on it. The programming method was then successfully used in a patient with a jammed Codman Hakim programmable valve. After successful programming using this method, clinical and radiological follow-up of the patient was advised.

Safety and efficacy of gravitational shunt valves in patients with idiopathic normal pressure hydrocephalus: a pragmatic, randomised, open label, multicentre trial (SVASONA)

OBJECTIVES

To investigate whether gravitational valves reduce the risk of overdrainage complications compared with programmable valves in ventriculoperitoneal (VP) shunt surgery for idiopathic normal pressure hydrocephalus (iNPH).

BACKGROUND

Patients with iNPH may benefit from VP shunting but are prone to overdrainage complications during posture changes. Gravitational valves with tantalum balls are considered to reduce the risk of overdrainage but their clinical effectiveness is unclear.

METHODS

We conducted a pragmatic, randomised, multicentre trial comparing gravitational with non-gravitational programmable valves in patients with iNPH eligible for VP shunting. The primary endpoint was any clinical or radiological sign (headache, nausea, vomiting, subdural effusion or slit ventricle) of overdrainage 6 months after randomisation. We also assessed disease specific instruments (Black and Kiefer Scale) and Physical and Mental Component Scores of the Short Form 12 (SF-12) generic health questionnaire.

RESULTS

We enrolled 145 patients (mean (SD) age 71.9 (6.9) years), 137 of whom were available for endpoint analysis. After 6 months, 29 patients in the standard and five patients in the gravitational shunt group developed overdrainage (risk difference -36%, 95% CI -49% to -23%; p<0.001). This difference exceeded predetermined stopping rules and resulted in premature discontinuation of patient recruitment. Disease specific outcome scales did not differ between the groups although there was a significant advantage of the gravitational device in the SF-12 Mental Component Scores at the 6 and 12 month visits.

CONCLUSIONS

Implanting a gravitational rather than another type of valve will avoid one additional overdrainage complication in about every third patient undergoing VP shunting for iNPH.

Programmable valve represents an efficient and safe tool in the treatment of idiopathic normal-pressure hydrocephalus patients

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait disturbance, dementia and /or urinary incontinence, dilation of the ventricular system and normal opening cerebrospinal fluid pressure. Shunt surgery is the standard treatment of iNHP. Diversions with programmable valves are recommended, once drainage pressure can be changed. However, well-defined protocols still lack guiding the steps to attain proper pressure for each patient. Methods: In our study, we reported the experience of shunting 24 patients with iNPH using Strata® (Medtronic) valve, following a protocol based on a positive Tap Test. Results: We observed clinical improvement in 20 patients and stability/worsening in 4 patients. Complications occurred in five patients, including one death. The results display improvement, and complications occurred at a lower rate than reported in other studies. Conclusions: The Strata® valve used in the proposed protocol represents an efficient and safe tool in the treatment of iNPH.

Shunt survival rates by using the adjustable differential pressure valve combined with a gravitational unit (proGAV) in pediatric neurosurgery

OBJECT

Overdrainage is a chronic complication in shunted pediatric patients with hydrocephalus. The use of adjustability of differential pressure (DP) valves in combination with antisiphoning devices may help to overcome this sequela and may diminish the rate of possible shunt failures. The purpose of this retrospective study is to report our experience on shunt survival and infection rate with an adjustable DP valve with integrated gravitational unit in pediatric hydrocephalus.

METHODS

The proGAV consists of an adjustable differential pressure (DP) valve and a gravitational unit. During the time period of July 2004 and December 2009, a total of 237 adjustable gravitational valves were used in 203 children (age, 6.5 ± 6.54; 0-27 years). In the follow-up period, valve and shunt failures as well as rate of infection were recorded.

RESULTS

Within the average follow-up time of 21.9 ± 10.3 months (range, 6-72 months), the valve survival rate was 83.8 %. The overall shunt survival rate including all necessary revisions was 64.3 %. Looking at the group of infants (<1 year of age) within the cohort, the valve survival rate was 77.3 % and the shunt survival rate was 60.9 %. The overall infection rate was 4.6 %.

CONCLUSION

In a concept of avoiding chronic overdrainage by using the proGAV in hydrocephalic children, we observed a good rate of valve and shunt survival. Compared to previous reported series, we experienced the proGAV as a reliable tool for the treatment of pediatric hydrocephalus.

In vitro experiment for verification of the tandem shunt valve system: a novel method for treating hydrocephalus by flexibly controlling cerebrospinal fluid flow and intracranial pressure

OBJECT

The CSF shunt valve is a medical device whose main function is to regulate intracranial pressure and drain excess CSF. The authors have developed a new therapeutic method for treating hydrocephalus, namely the tandem shunt valve system, which has the potential of flexibly controlling the CSF flow rate and intracranial pressure in patients.

METHODS

The properties of the tandem system were verified by performing in vitro experiments. An in vitro system with a manometer was built to measure pressure and flow rates of water in open systems using the Codman Hakim Programmable Valve and the Strata adjustable pressure programmable valve. A single valve and 2 single shunt valves connected in series (the tandem shunt valve system) were connected to the manometer to check the final pressure.

RESULTS

Conventional single shunt valve systems require valve pressures to be set higher to slow down the CSF flow rate, which inevitably results in a higher final pressure. On the other hand, the tandem shunt valve system uses the combination of 2 valves to slow the CSF flow rate without increasing the final pressure.

CONCLUSIONS

The authors succeeded in experimentally demonstrating in vitro results of tandem systems and their effectiveness by applying a model to show that the valve with the higher pressure setting determined the final pressure of the entire system and the flow rate became slower than single shunt valve systems.

Shunting with gravitational valves—can adjustments end the era of revisions for overdrainage-related events?

Object

Overdrainage of CSF remains an unsolved problem in shunt therapy. The aim of the present study was to evaluate treatment options on overdrainage-related events enabled by the new generation of adjustable gravity-assisted valves.

Methods

The authors retrospectively studied the clinical course of 250 consecutive adult patients with various etiologies of hydrocephalus after shunt insertion for different signs and symptoms of overdrainage. Primary and secondary overdrainage were differentiated. The authors correlated the incidence of overdrainage with etiology of hydrocephalus, opening valve pressure, and patient parameters such as weight and size. Depending on the severity of overdrainage, they elevated the opening pressure, and follow-up was performed until overdrainage was resolved.

Results

The authors found 39 cases (15.6%) involving overdrainage-related problems—23 primary and 16 secondary overdrainage. The median follow-up period in these 39 patients was 2.1 years. There was no correlation between the incidence of overdrainage and any of the following factors: sex, age, size, or weight of the patients. There was also no statistical significance among the different etiologies of hydrocephalus, with the exception of congenital hydrocephalus. All of the “complications” could be resolved by readjusting the opening pressure of the valve in one or multiple steps, avoiding further operations.

Conclusions

Modern adjustable and gravity-assisted valves enable surgeons to set the opening pressure relatively low to avoid underdrainage without significantly raising the incidence of overdrainage and to treat overdrainage-related clinical and radiological complications without surgical intervention.

Initial experience with the Codman Certas adjustable valve in the management of patients with hydrocephalus

Background

A new adjustable valve, the Codman Certas^TM valve for treatment of hydrocephalus was introduced into clinical practice in January 2011. It has 8 different settings with an opening pressure varying from 36 to over 400 mm H₂O at a flow rate of 20 mL/h. The 8th setting is designed to provide a "virtual off" function. The objective of this report is to describe the initial clinical experience with the Certas^TM valve and evaluate clinical usage with the main focus on the portable adjustment device - Therapeutic Management System (TMS), the “virtual off” setting and compatibility with magnetic resonance imaging (MRI).

Findings

Forty-two patients with hydrocephalus from different etiologies were treated with the Certas^TM adjustable shunt system. Data regarding implantation procedures, the use of the TMS system, x-ray imaging, and MRI procedures were recorded prospectively. All patients had clinical follow-up at four weeks after implantation and every three months until a stable clinical condition was obtained.

The mean time for follow-up was 8.6 months (1–16.6). Seventy-one adjustments were performed with the TMS, 12 were problematic. Twenty-nine MRI procedures were performed and did not cause accidental resetting. Five patients were treated with the "virtual off" function for a period.

Conclusions

We found the Certas^TM valve valuable in the treatment of hydrocephalus, usability of the TMS was high because it is small and portable, but in some cases we experienced adjustment problems with the first procedures performed by a surgeon, indicating that there is a learning curve. The "virtual off" function provided a possibility of treating over-drainage without the need for shunt ligation or other invasive procedures.

One-year outcome in the European multicentre study on iNPH

OBJECTIVES

To assess the 1-year outcome after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH).

METHODS

Patients (n = 142) were prospectively included in the European multicentre study by 13 centres. Diagnoses were based solely on clinical and radiological findings. All received a programmable ventriculoperitoneal shunt. Re-examinations, 12 months after surgery, were performed in 115 patients, and the outcome was assessed by the modified Rankin scale (mRs) and a new iNPH grading scale. Improvement was defined as ≥1 step on the mRs and ≥5 points on the iNPH scale.

RESULTS

The scores on both scales were significantly improved after 1 year of shunt treatment (Ps < 0.001). Sixty-nine per cent of the patients were improved according to the mRs and 84% according to the iNPH scale. The proportion able to live independently (scores 0-2 on the mRs) was increased from 53% before to 82% 12 months after surgery (P < 0.001). Neither classification (typical or questionable) nor comorbidity affected the level of improvement. Patients not completing the study were worse off with regard to their clinical condition at entry than completers. Twenty-eight per cent of the patients experienced complications and were either conservatively (13%) or surgically (15%) treated.

CONCLUSION

The results of this prospective multicentre study on patients with iNPH diagnosed solely on clinical and radiological criteria support shunt surgery in patients presenting with symptoms and signs and MRI findings suggestive of iNPH.

Risk factors for recurrent shunt infections in children

Risk factors for recurrent shunt-related cerebrospinal fluid (CSF) infections were analyzed. A total of 58 children were treated for initial shunt infections (ISI): all children were treated with antibiotics and CSF drainage, either by removal of the shunt system and insertion of an external ventricular drainage (EVD) catheter (44 children, 75.9%) or by externalization of the existing ventricular catheter (14 children, 24.1%). Recurrent shunt infections (RSI) were detected in 15 children: nine had been treated with shunt removal and insertion of a new EVD catheter and six had been treated with externalization of the existing ventricular catheter. There was a statistically significant increase in the number of RSI in children treated with externalization of the existing ventricular catheter. Thus, to reduce the risk of RSI, total shunt removal and insertion of a new EVD catheter is preferred.

Role of endoscopic third ventriculostomy at infected cerebrospinal fluid shunt removal

OBJECT

Cerebrospinal fluid shunt infection is distressing, especially in the pediatric population. Usually, infected CSF shunts are removed, and after temporary external CSF drainage, reinsertion of the CSF shunt is necessary. Unfortunately, it is not rare to encounter CSF reinfection after shunt renewal, and furthermore, the reinserted CSF shunt is at a considerable risk of malfunction. Endoscopic third ventriculostomy (ETV) is a potent option in managing CSF shunt infection, although ETV failure may occur more frequently when it is used to remove an infected shunt. The authors retrospectively evaluated CSF reinfection after using ETV during removal of infected CSF shunts; then the longevity of ETV and of successive reinserted ventriculoperitoneal shunts (VPSs) after ETV failure were also examined.

METHODS

Children with shunted hydrocephalus were retrospectively reviewed, and data on their initial CSF shunt infections were extracted. Thirty-six children underwent VPS reinsertion (the VPS group), and 9 underwent ETV after removal of the infected CSF shunt (the ETV group). As the primary outcome, ETV efficacy against CSF reinfection within 6 months was analyzed by comparing the reinfection rates, and the risk factors for CSF reinfection were analyzed by logistic regression. The longevity of the reinserted shunt in the VPS group was calculated using the Kaplan-Meier method, which was compared with ETV longevity as the secondary outcome, and also with the longevity of reinserted VPSs in the ETV group after ETV failure as the tertiary outcome.

RESULTS

Reinfection of CSF was seen in 27.8% of children in the VPS group. Among 9 children in the ETV group, only 1 (11.1%) had CSF reinfection. However, logistic regression analysis failed to show that performing ETV was a significant factor protecting against CSF reinfection: the significant risk factors were younger age at reinsertion of VPS or ETV (p = 0.037) and a history of shunt revisions (p = 0.011). The longevity of reinserted VPSs in the VPS group was calculated to be 658 ± 166.3 days (mean ± SE). Longevity of ETV was compared in the analysis of the secondary outcome, which was 929.2 ± 511.1 days, and there were no significant differences between these durations. Only 2 ETVs stayed patent, and a VPS was eventually implanted in the other 7 children. The longevity of this reinserted VPS in the ETV group, calculated based on these 7 children, was 2011.1 ± 540.7 days, which was confirmed to be longer than that in the VPS group (p = 0.031).

CONCLUSIONS

Although the protective effect of using ETV during removal of an infected CSF shunt on reinfection is marginal, the ETV longevity can be considered equivalent to that of reinserted VPSs. Even if ETV failure occurs, the reinserted VPS has significantly better longevity than a VPS reinserted without using ETV, and use of ETV during infected CSF shunt removal can be considered a potent alternative or at least an adjunct to VPS reinsertion.

Ten years of clinical experience in the use of fixed-pressure versus programmable valves: a retrospective study of 159 patients

AIM

The aim of this study was to present our 10-year experience with the use of fixed-pressure and programmable valves in the treatment of adult patients requiring cerebrospinal fluid (CSF) diversion.

MATERIAL AND METHODS

Patients (n = 159; 89 male and 70 female) suffering from hydrocephalus of various causes underwent CSF shunt implantation. Forty fixed-pressure and 119 programmable valves were initially implanted.

RESULTS

The observed revision rate was 40% in patients with fixed-pressure valves. In 20% of these patients, a revision due to valve mechanism malfunction was undertaken, and the initial valve was replaced with a programmable one. The revision rate in the adjustable-pressure valve subgroup was 20%. The infection rate for the fixed-pressure and programmable valve subgroups were 3%, and 1.7%, respectively. Similarly, subdural fluid collections were noticed in 17% and 4% of patients with fixed-pressure valves and programmable valves, respectively.

CONCLUSIONS

The revision and over-drainage rates were significantly lower when using programmable valves, and thus, this type of valve is preferred whenever CSF has to be diverted.

More malfunctioning Medos Hakim programmable valves: cause for concern?

Object

In recent years, the authors have noticed a growing number of programmable valve defects at their institution. Therefore, they conducted this study to evaluate the increased incidence of malfunctioning valves.

Methods

They investigated all revisions that had been performed at their institution between 1994 and 2010 for dislodgement of the stator of a standard Medos Hakim programmable valve with a prechamber.

Results

Fifteen valves were removed because of dislodged stators. The valves had been implanted between May 16, 1993, and December 27, 2002, and were explanted between February 19, 2006, and January 22, 2010. Thus, the valves had been in place for a mean period of 11 years (median 11 years, range 7–14 years). The percentage of dislodged stators was almost 3% (15 of 546 valves). Particularly noteworthy is that all malfunctioning valves were found in children who had been younger than 1 year of age at the time of implantation.

Conclusions

Medos Hakim programmable valve malfunctions are rare events but should receive careful attention. When the pressure setting cannot be adjusted, a malfunction should always be suspected and radiographic imaging should be performed to assess the valve. Stator dislodgement is the most serious form of valve adjustment failure.