PROSAIKA: a prospective multicenter registry with the first programmable gravitational device for hydrocephalus shunting.

OBJECTIVE: Cerebrospinal fluid (CSF) overdrainage is a major problem in shunt therapy for hydrocephalus. The adjustable gravitational valve proSA allows for the first time a targeted compensation for overdrainage in the upright position without interfering with the differential pressure valve. To evaluate benefit, safety and reliability, the multicenter prospective registry PROSAIKA was conducted in 10 German neurosurgical centers. METHODS: Between March 2009 and July 2010, 120 hydrocephalic patients undergoing first time shunt implantation or shunt revision using proSA entered the study. 93 patients completed the 12 months follow-up. RESULTS: Hydrocephalus symptoms were improved in 86%, unchanged in 9% and deteriorated in 3%. In 51%, the proSA opening pressure was readjusted one or several times to treat suspected suboptimal shunt function, this resulted in clinical improvement in 55%, no change in 25%, and deterioration in 20% of these patients. The 1 year censored proSA shunt survival rate was 89%. Device related shunt failure was seen in two cases. CONCLUSIONS: This is the first clinical report on the implantation of the adjustable gravitational valve proSA with a follow-up of 12 months in a substantial number of patients. Irrespective of different hydrocephalus etiologies and indications for shunt surgery, the overall results after 12 months were very satisfying. The high frequency of valve readjustments underlines the fact that preoperative selection of the appropriate valve opening pressure is difficult. The low number of revisions and complications compared to other valves proves that proSA implantation adds no further risk; this valve is reliable, helpful and safe.

Ventriculoperitoneal Shunt Tip as a Rare Cause for Recurrent Pain Episodes in a Child: Think Irritable Peritoneum.

Ventriculoperitoneal (VP) shunting is an established treatment to regulate the drainage of cerebrospinal fluid (CSF) in posthaemorrhagic hydrocephalus. Several complications (e.g. blockage of CSF shunting, overdrainage, but also catheter-related perforation of abdominal organs, etc.) may occur and may lead to painful episodes, mostly headache, in these children. Here, we report on a 7-year-old child with recurrent painful episodes after revision of a VP shunt that subsided only after repositioning of the abdominal tip of the VP shunt. Visceral irritation by a malpositioned VP shunt should be considered as a cause for recurrent pain in non-verbal children without other relevant clinical findings.

Predictors of subsequent overdrainage and clinical outcomes after ventriculoperitoneal shunting for idiopathic normal pressure hydrocephalus.

BACKGROUND: Little is known about variables associated with overdrainage complications and neurofunctional and health-related quality of life outcomes in idiopathic normal-pressure hydrocephalus (iNPH) patients after shunt surgery. OBJECTIVE: To identify candidate demographic and disease-specific predictors of overdrainage and patient-related outcomes, allowing for more personalized care of patients with iNPH. METHODS: This was a secondary analysis of the dataset of the SVASONA study, a multicenter randomized trial comparing gravitational and conventional gravitational valves for treating iNPH. We evaluated the association between baseline items and the incidence of overdrainage, using different endpoint definitions. RESULTS: We identified only a few variables associated with a possible increased risk of overdrainage. Apart from using conventional rather than gravitational valves, longer duration of surgery and female sex were associated with a higher risk of clinical signs and symptoms suggestive of overdrainage (hazard ratio: 1.02, 95% confidence interval: 1.01-1.04 and 1.84, 95% confidence interval: 0.81-4.16). The occurrence of clinical symptoms of overdrainage, and the need for exchanging a programmable by a gravitational valve may adversely affect disease-specific outcomes like the Kiefer score. CONCLUSION: Few, if any, baseline and treatment characteristics may be helpful in estimating the individual risk of complications and clinical outcomes after shunt surgery for iNPH. Patients should be informed that longer surgery for any reason may increase the risk of later overdrainage. Also, women should be counseled about a sex-associated increased risk of the development of clinical symptoms of overdrainage, although the latter cannot be distinguished from a generally higher prevalence of headaches in the female population.

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.

Cerebral MRI and EEG studies in the initial management of pediatric headaches.

BACKGROUND AND STUDY PURPOSE: High resolution imaging modalities and electroencephalographic studies (EEG) are used in the assessment of children with headaches. We evaluated the role of cerebral MRI (cMRI) and EEG in the initial assessment of children with headache as the chief complaint of initial presentation. METHODS: A retrospective chart analysis was performed at a tertiary University Hospital. RESULTS: 209 patients were included in this study [mean age 11.3 years; male 91 (43.5%); female 118 (56.5%)]. The following types of headaches were seen: Unclassified headache: 23.4%; probable migraine 17.2%, migraine without aura 13.4%, complicated migraine 12.4%, migraine with aura 1.0%; tension-type 15.3%, and cluster headaches 0.5%, and secondary headaches 16.7%. In 93 children (44.5%) abnormal physical/neurological findings were noted (multiple entries possible). On cMRI studies the following findings were seen: Infection of sinuses (7.2%), pineal cysts (2.4%), arachnoidial cyst and Chiari malformation (1.9%), unspecified signal enhancement (1.0%), and pituitary enlargement, inflammatory lesion, angioma, cerebral ischaemia, and intra-cerebral cyst (each 0.5%). Electroencephalographic findings included both focal and generalised abnormal slowing (5.3%) and Spike-wave complexes (3.3%). CONCLUSIONS: Despite abnormal findings on neurological/physical examination in a substantial number of children with headaches, the yield of pathological cMRIs was low. The use of EEG recordings was not contributory to the diagnostic and therapeutic approach. More research is needed to better define those patients who are likely to have an intracranial pathology.

Intraventricular cooling during CSF infusion studies.

We implemented ventricular infusion studies on 33 patients suspected of idiopathic normal pressure hydrocephalus (iNPH), benign intracranial hypertension (BIH) or occlusive hydrocephalus (HOC) in order to confirm shunt indications. The initial scope was to study O(2) supply during infusion tests to exclude further violation of already vulnerable brains during ICP elevation. Intraventricular infusion was performed via ventricle catheters with the ICP tip sensor, while brain tissue oxygenation was measured with intraparenchymal Raumedic PTO probes. In 15 out of 23 (65%; 8 NPH, 2BIH, 5 HOC), pO(2) increased constantly (average 140%), while brain temperature decreased (range: 0.2-4.5°C) during the infusion studies. In another six patients, O(2) values remained largely stable during the infusion studies (4NPH, 1BIH, 1HOC). Cerebral deoxygenation during infusion tests occurred only in two patients (1NPH, 1HOC).Overall cerebral oxygenation and temperature inversely correlated well with some temporary delay regarding oxygenation state as a consequence of cerebral temperature. Probably, this effect is a consequence of reduced cerebral metabolism caused by local cooling. We hypothesise that such cooling is mediated via the large basal arteries and suggest that such a pathophysiology, ICP-controlled local cooling, might offer a new option for brain protection (e.g. in an ICP crisis).

On the method of a randomised comparison of programmable valves with and without gravitational units: the SVASONA study.

OBJECTIVE: The supremacy of low-pressure valves (LPV) in the therapy of patients with idiopathic normal pressure hydrocephalus (iNPH) has been proven by the Dutch NPH study. The downside of LPVs is the high rate of overdrainage complications. In the meantime gravitational units have been developed with the objective of minimising overdrainage complications. Do these gravitational units allow the same favourable outcomes as in the Dutch NPH study without overdrainage complications? The goal of this prospective randomised controlled multicentre trial is to compare the rate of overdrainage complications after shunt surgery with programmable valves with or without a gravitational unit. METHOD: Patients suspected with iNPH with gait ataxia and one or two other symptoms of Hakim's triad and enlarged ventricles on CT or MRI underwent a cerebrospinal fluid (CSF) infusion test, CSF tap test and/or continuous ICP measurement in seven experienced centres. If iNPH was diagnosed the patients were randomised to receive a ventriculoperitoneal shunt with a programmable valve with or without a gravitational unit. The patients were followed up for 3, 6 and 12 months after surgery. The primary hypothesis of the study was that programmable valves with gravitational units will reduce the rate of overdrainage from 25% to 10%. The outcome measured by iNPH-specific outcome scales (Kiefer score, Black grading scale) and the generic quality of life (short form 12, SF12) was defined as the secondary endpoint. To detect the hypothesised difference in the incidence of overdrainage with a type I error of 5% and a type II error of 20%, correcting for multiple testing and an anticipated drop-out rate of 10%, we planned to enrol 250 patients. To ensure safety and efficacy we performed a planned interim analysis halfway. RESULTS: The study design has been found to be effective with regard to the primary hypothesis. CONCLUSION: The design of the SVASONA study was developed to be able to confirm the primary hypothesis. Thus, the method of the study should solve the dilemma of the Dutch NPH study by the randomised comparison of LPVs with and without gravitational units.

Reduction of shunt obstructions by using a peel-away sheath technique? A multicenter prospective randomized trial.

OBJECTIVE: Shunt obstructions may partly be caused by brain debris, which intrude into the ventricular catheter during ventricle puncture. Avoiding contact between the catheter and brain tissue, by using a peel-away sheath, should reduce the number of shunt failures caused by obstruction. To test this hypothesis, we conducted a randomized, prospective multicenter study. METHODS: 201 patients from 6 different neurosurgical centers in Germany receiving a ventriculo-peritoneal shunt were included in this study. Of these, 177 patients completed a 1-year follow-up period. Surgery was randomized in a 1 to 1 fashion, such that out of 177 procedures, 91 were performed using a peel-away sheath and 86 were performed without. The rate of surgical re-interventions and shunt obstructions within a 12-month period was recorded. RESULTS: Within 1 year post-surgery, 17 shunt obstructions (9.6%) leading to shunt revisions were recorded. However, no difference was found between surgeries performed using a peel-away sheath (9.9%) or not (9.3%). The overall shunt infection rate was 2.8% and the shunt revision rate for overdrainage was 3.9%. CONCLUSIONS: The theoretical advantages attributed to the use of a peel-away sheath to introduce a ventricular catheter could not be confirmed in this randomized study, suggesting that the proposed role of brain debris in shunt obstructions may be overestimated.

Glue instead of stitches: a minor change of the operative technique with a serious impact on the shunt infection rate.

INTRODUCTION: Shunt infections are still one of the most important complications of shunt surgery. We observed shunt infections coming from wound breakdown due to minimal CSF leakage from subcutaneous CSF accumulation, which is often unavoidable in babies over the borehole, along the fibers of stitches that close the superficial skin. Whether such secondary shunt infections might be overcome by avoiding stitches has been studied. MATERIALS AND METHODS: We examined 90 children experiencing their first shunt insertion between September 1998 and April 2008. We divided the children into two groups. Wound closure was performed with absorbable subcutaneous one-on-one sutures with counter-sunk knots in both groups. In one group, octylcyanoacrylate tissue adhesive was used for the final layer closure of the skin (44 children); in the other group, non-absorbable one-on-one single skin sutures were used (46 children). RESULTS: Using the glue, we reduced the wound dehiscence rate from 24% to 2% and the infection rate from 17% to 0%. CONCLUSION: A minimal change of operative technique substantially affects the shunt infection rate due to the extermination of the "wick-effect" along filaments used to close the skin. Furthermore, Dermabond itself has a bactericidal effect.

Animal experiments to evaluate complications of foreign materials on silicone with shunt catheters: preliminary results.

OBJECTIVE: Use of silicone to manufacture hydrocephalus shunts has been critical for the successful introduction of modern shunt therapy. However reactions to foreign material cause biodegradation, calcification, and massive scarring, and their impact on the still high shunt failure rate might have been undervalued in the past. We established an animal model to simulate the conditions and reactions with the silicone catheter in human patients. METHODS: We implanted catheters from different hydrocephalus shunt manufacturers available on the world market in 12 four-week old Wistar rats. To mimic shearing forces and tensile stress, the tubes were firmly fixed proximally and distally in a growing rat. The catheters remained in the subcutaneous tissue for 1 year before being removed and studied using scanning electron microscopy and histological studies. RESULTS: All of the implanted long catheters showed fractures and calcification on their surfaces, whereas the short fragmented catheters did not. CONCLUSION: The immunological reactions with silicone and the biodegradation of the material can be simulated in this animal model to study details of the pathophysiology of this process.

Intracranial irregularities beside hydrocephalus in H-Tx rats.

INTRODUCTION: It has been well documented that up to 70% of H-Tx rats' offspring suffer from severe hydrocephalus, which can be fatal if it remains untreated. Some offspring also have non-fatal moderate hydrocephalus allowing a normal life expectancy. The objective of this study was finding other morphological intracranial abnormalities that are not directly related to hydrocephalus. METHOD: An MRT for small animals (Bruker, Biospec, Erlangen Germany) with a 2.4 T magnet at 100 MHz has been used to study 98 apparently non-hydrocephalic H-Tx rats. T2-weighted 2D-RARE, T2-weighted 3D-Turbo-RARE sequence and T1-weighted 3D-gradient-echo sequences were used. RESULTS: Apart from 36% of animals with moderate or mild hydrocephalus, we found one animal with a cystic cerebellar malformation similar to an arachnoid cyst with minimal space occupying effects. Nine rats had a mild or moderate-sized unilateral enlargement of one lateral ventricle, but a causative occlusion of the Foramen of Monroe could not be verified. Finally, one animal with huge hydrocephalus had a midline cystic malformation between both cerebral hemispheres. CONCLUSION: Aside from the well-documented hydrocephalus, H-Tx rats may develop other intracranial malformations that have not yet been documented in the literature.

Experiences with a gravity-assisted valve in hydrocephalic children. Clinical article.

OBJECT: Over the past decade, a gravity-assisted valve (GAV) has become a standard device in many European pediatric hydrocephalus centers. Because past comparative clinical outcome studies on valve design have not included any GAV, the authors in this trial evaluated the early results of GAV applications in a pediatric population. METHODS: For a minimum of 2 years the authors monitored 169 of 182 hydrocephalic children who received a pediatric GAV at their first CSF shunt insertion (61.5%) or as a substitute for any differential pressure valve (38.5%) at 1 of 7 European pediatric hydrocephalus centers. Outcomes were categorized as valve survival (primary outcome) or shunt survival (secondary outcome). The end point was defined as valve explantation. RESULTS: Within a follow-up period of 2 years, the valve remained functional in 130 (76.9%) of 169 patients. One hundred eight of these patients (63.9%) had an uncomplicated clinical course without any subsequent surgery, and 22 (13%) were submitted to a valve-preserving catheter revision without any further complications during the follow-up period. Thirty-nine patients (23.1%) reached an end point of valve explantation: 13 valve failures from infection (7.7%), 8 (4.7%) from overdrainage, and 18 (10.6%) from underdrainage. CONCLUSIONS: Compared with nongravitational shunt designs, a GAV does not substantially affect the early complication rate. Valve-preserving shunt revisions do not increase the risk of subsequent valve failure and therefore should not be defined as an end point in studies on valve design. A significant impact of any well-established valve design on the early complication rate in shunt surgery is not supported by any current data; therefore, this correlation should be dismissed. As overdrainage-related complications have been shown to occur late, the presumed advantages of a pediatric GAV remain to be shown in a long-term study.