Programmable Valve Research Articles

Improved Outcome in Shunted iNPH with a Combination of a Codman Hakim Programmable Valve and an Aesculap-Miethke ShuntAssistant

Low pressure valves with ventriculoperitoneal shunts have been proven to lead to good outcomes in the treatment of idiopathic normal pressure hydrocephalus. However, overdrainage complications are often seen with low opening pressures. Efforts have been made to obtain good outcomes without overdrainage complications by decreasing the hydrostatic pressure component using special valve constructions. The aim of this study was to ascertain whether it is possible to optimise outcome with the implantation of both an adjustable valve and a gravitational unit. Between July 2003 and July 2006, 42 patients underwent ventriculoperitoneal shunt surgery with a Codman Hakim programmable valve (Codman, Johnson & Johnson, Raynham, USA) and a Miethke ShuntAssistant (Miethke Gmbh, Potsdam, Germany). These patients were followed up for a period between 2 years (35 patients) and 4 years (18 patients) after surgery. The systematic re-programming of the valves from 100 mmH(2)O to 70 mmH(2)O and then to 50 mmH(2)O after 3 months allowed the brain to adapt to the implanted valve without the complication of overdrainage. The responder rates were 86% after two years and 83% after four years. Overdrainage was seen in 3% of the cases, mechanical complications occurred in 6%. Our results indicate that the combination of a Codman Hakim programmable valve with a Miethke ShuntAssistant could improve outcomes in shunted iNPH. This finding has yet to be proven in a larger, prospective randomized trial.

The parallel use of endoscopic fenestration and a cystoperitoneal shunt with programmable valve to treat arachnoid cysts: experience and hypothesis

The authors share their experience of the treatment of arachnoid cysts with endoscopic fenestration and cystoperitoneal shunt placement during the same operation. The importance of this strategy is related to the fact that the shunt can induce the collapse of the cyst and that the endoscopic fenestration could make it possible to remove the shunt, avoiding the phenomenon of shunt dependence. Between 1996 and 2005, 35 patients with an arachnoid cyst were treated using endoscopic fenestration and placement of a programmable shunt. The patients' ages (70% boys and 30% girls) ranged from 2 months to 16 years. These patients were reviewed with MR imaging and clinical examination. The cyst volumes and clinical examinations were evaluated. No serious complications were reported; the cyst disappeared in 60% of the cases, and in 54% of the cases it was possible to remove the shunt without shunt dependence. In the authors' view, this strategy seems easy, does not take longer than a simple shunt surgery or an endoscopic cystostomy alone, and can be useful for treatment of arachnoid cysts in all locations.

Factors influencing spinal canal stenosis in patients with long-term controlled hydrocephalus treated with cerebrospinal fluid shunt

Spinal canal stenosis (CS) occurs in patients with hydrocephalus who are treated with cerebrospinal fluid (CSF) shunting. The pathophysiology of CS comprises CSF overdrainage. We analyzed the incidence of CS and the factors causing it. Thirty-three patients who underwent ventriculoperitoneal shunt during childhood visited the Outpatient Department in Yamaguchi University Hospital in 2006. Diameters of spinal canal at C(4) were measured. Treatment procedure, age, and type of hydrocephalus in the patients with CS were compared with those without CS. Of the 33 patients, 10 (30.3%) presented CS, and two (6.1%) were symptomatic. A low-pressure valve caused CS with a significantly higher incidence than a medium- or high-pressure valve (60.0% vs. 17.4%, P < 0.05). Although the difference was not significant, the average age of shunt insertion for a patient with CS was slightly less (0.87 +/- 0.99) than for a patient without CS (1.63 +/- 1.58). No differences in the CS incidence were observed between obstructive and communicating hydrocephalus. In order to prevent CS, the hydrocephalus should be appropriately controlled by using a medium- or high-pressure valve until the diameter of the spinal canal reaches the required level. Adjustment of the programmable valve with the patient's growth should be ideal.

Programmable CSF Shunt Valves: Radiographic Identification and Interpretation

The programmable CSF shunt valve has become an important tool in hydrocephalus treatment, particularly in the NPH population and in pediatric patients with complex hydrocephalus. The purpose of this study is to provide a single reference for the identification of programmable shunt valves and the interpretation of programmable shunt valve settings. Four major manufacturers of programmable shunts agreed to participate in this study. Each provided radiographic images and legends for their appropriate interpretation. Issues of MR imaging compatibility for each valve are also discussed.

Overdrainage of cerebrospinal fluid caused by detachment of the pressure control cam in a programmable valve after 3-tesla magnetic resonance imaging

The authors report a rare case of overdrainage of the CSF caused by the malfunction of a Codman-Hakim programmable valve (CHPV) following a 3-T MR imaging procedure. Nine years ago this 72-year-old woman underwent ventriculoperitoneal shunt placement with a CHPV system for hydrocephalus due to subarachnoid hemorrhage. The postoperative course was uneventful and the system functioned well. A radiograph obtained immediately after 3-T MR imaging revealed that the pressure control cam in the valve system was detached from the base plate. Intracranial hypotension syndrome occurred several hours after the MR imaging study, and a CT scan revealed a decrease in ventricle size. A revision of the system promptly resolved the symptoms, and a postoperative CT scan revealed that the ventricle size was restored to normal. Examination of the extracted valve showed a Y-shaped crack in the plastic housing as well as detachment of the white marker and cam from the base plate. A reduction in the power of the flat spring to press the valve ball led to CSF overdrainage because of a loss of support by the cam. Because the patient had incurred no head injury during the day and radiographic studies of the system 5 years previously had shown detachment of the white marker, damage to the system might have been caused by a past impact. These facts may indicate that the antimagnetic performance of the system could have decreased due to a previous impact and that the strong magnetic force in a 3-T MR imaging environment might have caused detachment of the cam.

Programmable valve shunts: are they really better?

Programmable valve shunts allows selection of opening pressure of shunt valve. In the presented article, a unique complication pertaining to programmable shunts has been discussed. A 5-year-old boy who had tectal plate low grade glioma with obstructive hydrocephalus was managed with Codman programmable ventriculoperitoneal shunt. There was a spontaneous change in the opening pressure of the shunt valve leading to shunt malfunction. Routinely used household appliances produce a magnetic field strong enough to cause change in the setting of shunt valve pressure and may lead to valve malfunction. Other causes of programmable valve malfunction also discussed.

A Comparative Result of Ventriculoperitoneal Shunt, Focusing Mainly on Gravity-Assisted Valve and Programmable Valve

Despite rapid evolution of shunt devices, the complication rates remain high. The most common causes are turning from obstruction, infection, and overdrainage into mainly underdrainage. We investigated the incidence of complications in a consecutive series of hydrocephalic patients. From January 2002 to December 2009, 111 patients underwent ventriculoperitoneal (VP) shunting at our hospital. We documented shunt failures and complications according to valve type, primary disease, and number of revisions. Overall shunt survival time was 268 weeks. Mean survival time of gravity-assisted valve (GAV) was 222 weeks versus 286 weeks for other shunts. Survival time of programmable valves (264 weeks) was longer than that of pressure-controlled valves (186 weeks). The most common cause for shunt revision was underdrainage (13 valves). The revision rate due to underdrainage in patients with GAV (7 of 10 patients) was higher than that for other valve types. Of 7 patients requiring revision for GAV underdrainage, 6 patients were bedridden. The overall infection rate was 3.6%, which was lower than reported series. Seven patients demonstrating overdrainage had cranial defects when operations were performed (41%), and overdrainage was improved in 5 patients after cranioplasty. Although none of the differences was statistically significant, some of the observations were especially notable. If a candidate for VP shunting is bedridden, GAV may not be indicated because it could lead to underdrainage. Careful procedure and perioperative management can reduce infection rate. Cranioplasty performed prior to VP shunting may be beneficial.

Efficacy of the Programmable Valve in the Treatment of Hydrocephalus

Efficacy of the Programmable Valve in the Treatment of Hydrocephalus

Effect of transcranial magnetic stimulation on four types of pressure-programmable valves

Exposure to powerful magnetic fields may alter the settings of programmable ventriculoperitoneal shunt valves or even cause permanent damage to these devices. Transcranial magnetic stimulation (TMS) and magnetic resonance imaging both generate a high-intensity, focal magnetic field. To the best of our knowledge, there is no literature data on the compatibility of TMS with neurosurgical implants. The aim of the present in vitro study was to investigate the effects of TMS on four types of pressure-programmable valves (the Strata 2 from Medtronic, the Polaris from Sophysa, the ProGAV from Miethke, and a cylindrical valve from Codman-Hakim). We used a Magpro X100 stimulator (Medtronic) for monophasic or biphasic TMS via a circular or a figure-of-eight coil. Each valve setting was tested before and after exposure to TMS. Experiment 1: The effect of the coil-valve distance (10, 5, 2.5, and 1 cm) was assessed. Experiment 2: We mimicked in situ stimulation with a human mannequin by placing the valve in a retroauricular position, the TMS circular coil on the apex, and figure-of-eight coil centered over the primary motor area site. Temperature changes were monitored throughout the experiments. Experience 3: TMS-induced valve movements were assessed by using an in-house accelerometric setup. Our results primarily demonstrated that the Strata 2 and Codman-Hakim valves' settings were perturbed by TMS. There was no heating effect for any of the valves. However, TMS induced movements of the Strata 2, Polaris, and ProGAV valves. Experiment 1: The unsetting frequencies observed for the Strata 2 and the Codman-Hakim valve showed an influence of the distance, the coil model, and the magnetic field characteristics, whereas the Polaris and ProGAV's settings remained unchanged. Experiment 2: Unsetting occurred for Strata 2 valve with the circular coil only, whereas the Polaris, ProGAV, and Codman-Hakim valves' settings remained stable. Experiment 3: The Strata 2, Polaris, and ProGAV valves showed high-amplitude oscillations during TMS under all stimulation conditions, whereas the Codman-Hakim valve did not move. Our in vitro experiments showed that TMS can interfere with programmable shunt valves by inducing unsetting or movement. This finding suggests that great care must be taken if applying TMS in hydrocephalic, shunted patients.

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

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

Efficacy of conventional valves compared to programmable valves in managing children &amp; adolescents with hydrocephalus: a 450 valve retrospective study

Materials and methods The authors collected computerized data for all patients subjected to a CSF shunt insertion or revision except those with brain tumours from the Patient Data Management System and the Computer Information System of the Seattle Children's Hospital from 1 January 2000 through 31 December 2008. Data collected included the patient's diagnosis, birth date, details of the operation insertion and components of revisions, valve type and location, type and timing of prophylactic antibiotic administration, time of day of the operation, duration of operation, presence of a trainee, incidence of shunt complications and white blood cell (WBC) and red blood cell counts (RBC) in the CSF obtained at the time of operation. Patients were followed for a minimum of one year post-operatively and statistical analysis was done using Vassar STATS® and MedCalc® which included Chi Square, Kaplan Meier Survival Curves and multi-variant analysis. Results A total of 1,278 operations were analyzed that incorporated 450 valve (233 PVS & 217 NPVS) implantations (166) or revisions (284) for 306 patients. Patients with a PVS that were adjusted (≥ 6 mo after implantation) demonstrated no significant difference to rate of non-valve revision (X2 p = 0.63), infection(X2 p = 0.99), or overall valve survival (KM p = 0.24) compared to patients with NPVS. Complications leading to valve replacement of the initial implantation occurred in 42% of NPVS and 45% of PVS(X2 p = 0.89). By differentiating patients by their preoperative WBC (poly ≥ 3 or mono ≥ 50) and/or RBC ≥ 30 in the CSF (as indications for inflammation), revisions of NPVS were significantly greater in valve survival rate than the PVS (p = 0.002). No significant differences existed between the two valve systems for reason of revision, location, age of patient, time of day, duration of the operation type of antibiotic used or time of administration or presence of trainee.

Cochlear Implantation in the Presence of a Programmable Ventriculoperitoneal Shunt

Document challenges of cochlear implantation in the presence of a ventriculoperitoneal shunt (VPS) with a programmable valve. A 7-month-old, postmeningitic, hydrocephalic infant with profound sensorineural hearing loss. Ventriculoperitoneal shunt revision with a nonprogrammable valve and bilateral cochlear implantation. Magnetic fields generated by cochlear implant (CI) transmitting coil magnets were measured ex vivo. Successful implantation and elimination of potential hazardous interaction between CI and VPS. Index patient reviewed and magnetic field strength presented. Strong magnetic fields can potentially alter the pressure setting of programmable shunt valves, causing overdrainage or underdrainage and potential serious consequences. Clear communication between the involved medical specialties is required for optimal management of patients requiring both VPS and CI.

Lumboperitoneal shunt placement using computed tomography and fluoroscopy in conscious patients

The authors have developed a minimally invasive lumboperitoneal shunt placement procedure conducted after administration of a local anesthetic. The procedure involves placing a guide wire and a peel-away sheath under fluoroscopic and CT guidance. Between June 2004 and August 2006, 40 patients (21 men and 19 women; mean age 72.5 years [range 33-86 years]) underwent surgery. A Codman Hakim programmable valve system (82-3844, Codman & Shurtleff, Inc.) was used for the procedure. The mean operating time was 53 minutes, and 7 patients (17.5%) developed shunt dysfunction complications. These complications comprised an infected shunt valve in 2 patients, postoperative lower-limb pain in 1 patient, and shunt obstruction (caused by debris and hemorrhage) at the ventral and lumbar ends in 2 patients each. This procedure is less invasive than conventional lumboperitoneal shunt insertion and could be performed as an outpatient surgery for treatment of idiopathic normal-pressure hydrocephalus.

CSF overdrainage in shunted intracranial arachnoid cysts: a series and review

Cerebrospinal fluid (CSF) overdrainage in hydrocephalus is well recognized. Overshunting following cysto-peritoneal (CP) drainage in patients with arachnoid cysts (AC) is rarely documented. We report five patients with acquired Chiari malformation I and three with posterior fossa overcrowding due to excessive CSF drainage in shunted intracranial ACs. We review our observations and discuss the current knowledge on the pathogenesis and management of this complication. The medical records of the eight patients were analyzed in regard to clinical manifestation, cyst and shunt characteristics, management, and outcomes. Mean age of the patients was 5.5 years. After an average interval of 5 years, five patients developed symptoms related to hindbrain herniation and three to severe shunt overdrainage following CP shunting. Several management modalities were utilized that achieved a good result in seven instances. Some shunted ACs may evolve with overdrainage syndromes. Posterior fossa overcrowding and tonsillar herniation constitute their most severe forms. CSF hypotension, bone changes, venous engorgement, and probably cerebral chronic edema at the posterior fossa constitute the main factors involved in the pathogenesis of this entity. We also review previous instances of acquired Chiari malformation originating after AC shunting. Posterior fossa overcrowding and acquired Chiari I malformation can develop after excessive CSF drainage of intracranial ACs. Overshunting manifestations require prompt recognition and management. Preventive measures consist of making a stringent selection of cases being considered for surgery, avoiding CP drainage, and placing of a programmable valve as initial treatment of intracranial ACs if shunting is considered.

Management of a locked Strata valve

The PS Medical Strata valve is a programmable shunt valve used in the treatment of hydrocephalus that allows for noninvasive changes in the pressure setting using a magnet. The Strata valve is sensitive to magnetic fields, and reprogramming is frequently necessary after MR imaging. A known but rare complication of the Strata valve is that the rotor can become locked, causing shunt malfunction. This complication can only occur in a first generation Strata valve.

Management of cranial deformity following ventricular shunting

Ventricular shunt-induced craniosynostosis is a widely recognised cause of secondary craniosynostosis. We reviewed the management and long-term outcome of the cases of cranial deformity post cerebrospinal fluid shunting in our unit and compared these with previously published series. The Australian Craniofacial Unit and Department of Neurosurgery database was searched to identify cases of ventricular shunt-induced cranial deformity and a case note review was undertaken. Eight cases were identified, and all were shunted within 6 months of birth. Our patients required shunting with a low pressure valve for hydrocephalus secondary to either aqueduct stenosis or intraventricular haemorrhage. The diagnosis was made following computed tomography (CT) three-dimensional surface reconstruction of the skull. Two cases of confirmed suture fusion were treated with cranial vault remodelling and programmable shunt insertion. In six cases, the sutures were not completely fused on the CT images despite a scaphocephalic head shape. These patients were managed conservatively with close monitoring. Cranial vault remodelling together with insertion of programmable shunt valve is indicated in CT confirmed cases of secondary craniosynostosis.

Acute ventriculoperitoneal shunt malfunction following opening of the spinal subarachnoid space

This manuscript is an analysis of five patients with ventriculoperitoneal shunt malfunction following intradural lumbar spine operation. The authors attribute the cause of this shunt malfunction to the intracranial shunt catheter obstruction due to negative pressure at the lumbar site and cerebrospinal fluid drainage after lumbar subarachnoid space opening. Although the numbers are few, the speculation by the authors is insightful. This phenomenon is similar to slit ventricles due to normal pressure valve overdrainage in which high-pressure valve replacement is necessary. Further studies on patients with programmable valves that provide the ability of increasing a valve’s resistance before lumbar operation should prove this theory. Childs Nerv Syst (2009) 25:605 DOI 10.1007/s00381-008-0792-4

A Pressure Adjustment Protocol for Programmable Valves

There is no definite adjustment protocol for patients shunted with programmable valves. Therefore, we attempted to find an appropriate method to adjust the valve, initial valve-opening pressure, adjustment scale, adjustment time interval, and final valve-opening pressure of a programmable valve. Seventy patients with hydrocephalus of various etiologies were shunted with programmable shunting devices (Micro Valve with RICKHAM(R) Reservoir). The most common initial diseases were subarachnoid hemorrhage (SAH) and head trauma. Sixty-six patients had a communicating type of hydrocephalus, and 4 had an obstructive type of hydrocephalus. Fifty-one patients had normal pressure-type hydrocephalus and 19 patients had high pressure-type hydrocephalus. We set the initial valve pressure to 10-30 mmH(2)O, which is lower than the preoperative lumbar tapping pressure or the intraoperative ventricular tapping pressure, conducted brain computerized tomographic (CT) scans every 2 to 3 weeks, correlated results with clinical symptoms, and reset valve-opening pressures. Initial valve-opening pressures varied from 30 to 180 mmH(2)O (mean, 102 +/- 27.5 mmH(2)O). In high pressure-type hydrocephalus patients, we have set the initial valve-opening pressure from 100 to 180 mmH(2)O. We decreased the valve-opening pressure 20-30 mmH(2)O at every 2- or 3-week interval, until hydrocephalus-related symptoms improved and the size of the ventricle was normalized. There were 154 adjustments in 81 operations (mean, 1.9 times). In 19 high pressure-type patients, final valve-opening pressures were 30-160 mmH(2)O, and 16 (84%) patients' symptoms had nearly improved completely. However, in 51 normal pressure-type patients, only 31 (61%) had improved. Surprisingly, in 22 of the 31 normal pressure-type improved patients, final valve-opening pressures were 30 mmH(2)O (16 patients) and 40 mmH(2)O (6 patients). Furthermore, when final valve-opening pressures were adjusted to 30 mmH(2)O, 14 patients symptom was improved just at the point. There were 18 (22%) major complications : 7 subdural hygroma, 6 shunt obstructions, and 5 shunt infections. In normal pressure-type hydrocephalus, most patients improved when the final valve-opening pressure was 30 mmH(2)O. We suggest that all normal pressure-type hydrocephalus patients be shunted with programmable valves, and their initial valve-opening pressures set to 10-30 mmH(2)O below their preoperative cerebrospinal fluid (CSF) pressures. If final valve-opening pressures are lowered in 20 or 30 mmH(2)O scale at 2- or 3-week intervals, reaching a final pressure of 30 mmH(2)O, we believe that there is a low risk of overdrainage syndromes.

Magnetic toys: forbidden for pediatric patients with certain programmable shunt valves?

Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in which patients have encountered powerful electromagnetic fields such as those involved in magnetic resonance imaging, but the potential effects of magnetic toys on programmable valves are not well known. The magnetic properties of nine toy magnets were examined. To calculate the effect of a single magnet over a distance, the magnetic flux density was directly measured using a calibrated Hall probe at seven different positions between 0 and 120 mm from the magnet. Strata II small (Medtronic Inc.), Codman Hakim (Codman & Shurtleff), and Polaris (Sophysa) programmable valves were then tested to determine the effects of the toy magnets on each valve type. The maximal flux density of different magnetic toys differed between 17 and 540 mT, inversely proportional to the distance between toy and measurement instrument. Alterations to Strata and Codman valve settings could be effected with all the magnetic toys. The distances that still led to an alteration of the valve settings differed from 10 to 50 mm (Strata), compared with 5 to 30 mm (Codman). Valve settings of Polaris could not be altered by any toy at any distance due to its architecture with two magnets adjusted in opposite directions. This is the first report describing changes in the pressure setting of some adjustable valves caused by magnetic toys in close contact. Parents, surgeons, neurologists, pediatric oncologists, and paramedics should be informed about the potential dangers of magnetic toys to prevent unwanted changes to pressure settings.

Ist eine Therapieoptimierung durch die Implantation eines verstellbaren Medos-Codman-Ventils in Kombination mit einem Miethke-ShuntassistentAesculap® bei Patienten mit idiopathischen Normaldruckhydrozephalus möglich?

Zielstellung Bessere Krankheitsverläufe nach Implantation eines Niederdruckventils bei Patienten mit idiopathischem Normaldruckhydrozephalus werden mit einer deutlich höheren Überdrainagerate meist teuer erkauft. Kann die Kombination eines verstellbaren Ventils mit einer Gravitationseinheit eine Optimierung der Behandlungsergebnisse bewirken? Methode In einer prospektiven Verlaufsbeobachtung wurden 42 Patienten mit einem idiopathischen Normaldruckhydrozephalus operativ mit der vorgenannten Ventilkombination im Zeitraum von Juli 2003 bis Juli 2006 im Unfallkrankenhaus Berlin behandelt und nach 2 bzw. 4 Jahren (21 Patienten) hinsichtlich des Krankheitsverlaufes und möglicher Ventilkomplikationen untersucht. Ergebnisse Der Krankheitsverlauf korreliert mit der Öffnungsdruckstufe des Ventils. Die kontrollierte Ventilumstellung von 100 auf 70 mm H2O sowie auf 50 mm H2O nach 3 Monaten erlaubt eine optimale Adaptation des Gehirns an das implantierte Ventil ohne Überdrainagekomplikationen. 86 % der Patienten zeigten 2 Jahre nach der Shuntoperation bzw. 83 % 4 Jahre nach der Shuntoperation eine klinische Besserung. Schlussfolgerungen Die Kombination eines verstellbaren Differenzialdruckventils mit einer Schwerkrafteinheit stellt aus unserer Sicht zur Zeit die optimale Therapievariante bei Patienten mit idiopathischem Normaldruckhydrozephalus dar.