The application of controlled intracranial hypertension in slit ventricle syndrome patients with obstructive hydrocephalus and shunt malfunction

Chronic Pediatric Headache as a Manifestation of Shunt Over-Drainage and Slit Ventricle Syndrome in Patients Harboring a Cerebrospinal Fluid Diversion System: A Narrative Literature Review

The main subject of the current review is a specific subtype of headache, which is related to shunt over-drainage and slit ventricle syndrome, in pediatric patients harboring an implanted shunt device for the management of hydrocephalus. This clinical entity, along with its impairment regarding the quality of life of the affected individuals, is generally underestimated. This is partly due to the absence of universally agreed-upon diagnostic criteria, as well as due to a misunderstanding of the interactions among the implicated pathophysiological mechanisms. A lot of attempts have been performed to propose an integrative model, aiming at the determination of all the offending mechanisms of the shunt over-drainage syndrome, as well as the determination of all the clinical characteristics and related symptomatology that accompany these secondary headaches. This subcategory of headache, named postural dependent headache, can be associated with nausea, vomiting, and/or radiological signs of slim ventricles and/or subdural collections. The ultimate goal of our review is to draw clinicians' attention, especially that of those that are managing pediatric patients with permanent, long-standing, ventriculoperitoneal, or, less commonly, ventriculoatrial shunts. We attempted to elucidate all clinical and neurological characteristics that are inherently related to this type of headache, as well as to highlight the current management options. This specific subgroup of patients may eventually suffer from severe, intractable headaches, which may negatively impair their quality of daily living. In the absence of any other clinical condition that could be incriminated as the cause of the headache, shunt over-drainage should not be overlooked. On the contrary, it should be seriously taken into consideration, and its management should be added to the therapeutic armamentarium of such cases, which are difficult to be handled.

Management of Slit Ventricle Syndrome: A Single-Center Case Series of 32 Surgically Treated Patients

OBJECTIVE

Slit ventricle syndrome (SVS) is an iatrogenic disease occurring in patients with ventriculoperitoneal shunt. This article reports the management modalities and results in a case series from a single center.

METHODS

We reviewed a series 48 hospitalized patients with severe SVS whom we managed in a 10-year period. Thirty-seven patients harboring programmable valves (P-valves) first underwent attempts at valve reprogramming. This treatment produced no effect in 21 patients, who therefore required surgical treatment. Surgery was also required by 11 patients without P-valve. Accordingly, 32 patients had to be operatively treated by shunt externalization followed by valve replacement or endoscopic third ventriculostomy basing on intracranial pressure and ventricular size. The new valve was either ProGav Mietke (Aesculap) or Medos Codman (Integra), each equipped with its own antisiphon system. In selected cases, a programmable antisiphon system (ProSa Mietke) was used.

RESULTS

Surgical mortality was 3% and major morbidity accounted for 6%. Complete resolution was obtained in 55% of cases, improvement in 32%, and no effect or worsening in 13%. Only 1 patient became shunt free after endoscopic third ventriculostomy. Medos and ProGrav provided comparable outcomes, whereas ProSa was determinant in selected cases. Pediatric age, uncomplicated shunt courses, and short SVS histories were significantly favorable indicators.

CONCLUSIONS

SVS management remains problematic. However, this study individuated factors that may improve the outcome, such as wider use of P-valves to treat hydrocephalus, timely diagnosis of overdrainage, and earlier and more aggressive indications to manage SVS.

Slit ventricle syndrome: Historical considerations, diagnosis, pathophysiology, and treatment review

After the introduction of shunt treatment for the management of childhood hydrocephalus, a wide variety of complications related to this treatment modality have been recognized. The entity of slit ventricle syndrome (alternatively, symptomatic ventricular coaptation) is one of them, is frequently encountered in the pediatric population and its symptom complex resembles that of shunt failure. We conducted research on PubMed^®, MEDLINE^®, and Web of Science^®, using the keywords: “slit ventricles,” “slit ventricle syndrome,” “SVS” and “ventricular coaptation.” The aim of our review was to trace the advances made through the past decades, concerning our knowledge about the clinical characteristics, pathophysiology, and treatment options of this entity. The discrepancy among researchers about the offending etiology and the optimum treatment algorithm of this entity, as well as the necessity of an updated concept regarding shunt over drainage is analyzed. The multiple treatment modalities proposed and pathophysiologic mechanisms implicated for the treatment of slit ventricle syndrome illustrate the complexity of this entity. Consequently, the issue requires more detailed evaluation. In this review, we comment on all the main facets related to shunt over drainage and the resultant slit ventricle syndrome.

Shunt Overdrainage: Reappraisal of the Syndrome and Proposal for an Integrative Model

Although shunt overdrainage is a well-known complication in hydrocephalus management, the problem has been underestimated. Current literature suggests that the topic requires more examination. An insight into this condition is limited by a lack of universally agreed-upon diagnostic criteria, heterogeneity of published series, the multitude of different management options and misunderstanding of relationships among pathophysiological mechanisms involved. We carried out a review of the literature on clinical, radiological, intracranial pressure (ICP), pathophysiological and treatment concepts to finally propose an integrative model. Active prophylaxis and management are proposed according to this model based on determination of pathophysiological mechanisms and predisposing factors behind each individual case. As pathophysiology is progressively multifactorial, prevention of siphoning with gravitational valves or antisiphon devices is mandatory to avoid or minimize further complications. Shunt optimization or transferal and neuroendoscopy may be recommended when ventricular collapse and cerebrospinal fluid isolation appear. Cranial expansion may be useful in congenital or acquired craniocerebral disproportion and shunting the subarachnoid space in communicating venous hydrocephalus and idiopathic intracranial hypertension.

Endoscopy in the treatment of slit ventricle syndrome

The present study aimed to investigate the efficacy of endoscopy in the treatment of post-shunt placement for slit ventricle syndrome (SVS). Endoscopic surgery was performed on 18 patients with SVS between October 2004 and December 2012. Sex, age, causes of the hydrocephalus, ventricular size and imaging data were collected and analyzed. All patients were divided into two groups according to ventricular size and underwent endoscopic surgeries, including endoscopic third ventriculostomy (ETV), endoscopic aqueductoplasty and cystocisternostomy. All treated patients were observed postoperatively for a period of 2 to 3 weeks, and outpatient follow-up was subsequently scheduled for >12 months. Clinical results, including catheter adherence, shunt removal and complications, were analyzed during the follow-up period. The success rate of endoscopic surgery was indicated to be 82.7%. Syndromes caused by aqueductal stenosis in 15 patients who underwent ETV were relieved; however, syndromes in the 3 patients with cerebral cysticercosis, suprasellar arachnoid cysts, pinea larea glioma and communicating hydrocephalus, respectively, were not relieved and underwent shunt placement again. Brain parenchyma, choroid plexus and ependymal tissue were the predominant causes for catheter obstruction and the obstruction rate was indicated to be 77.8% (14/18). Complications, such as pseudobulbar paralysis, infection and intraventricular hemorrhage arose in 3 patients. The present study indicates that endoscopic treatments are effective and ETV may be considered as a recommended option in the treatment of post-shunt placement SVS in hydrocephalus patients.

The truth and coherence behind the concept of overdrainage of cerebrospinal fluid in hydrocephalic patients

INTRODUCTION

Overdrainage, siphoning, and slit-ventricle syndrome are well-documented complications of shunting in hydrocephalic patients. Despite the prevalence of these conditions, their mechanisms are still not fully understood. In this paper, the authors trace the concept of overdrainage and the related phenomena of siphoning and slit-ventricle syndrome.

PURPOSE

To provide a historical overview of overdrainage and to reignite discussion of a topic that has been settled.

METHODS AND RESULTS

A medical literature search and review were performed via Google Scholar. Of 565 publications, 3 primary papers were identified and a timeline was developed demonstrating the convergence of the aforementioned concepts. From the primary papers, 25 relevant publications were selected and further analyzed searching for hypothesis, evidence, and conclusions.

CONCLUSION

Overdrainage, siphoning, and slit-ventricle syndrome are associated concepts that have converged into a pathophysiological theory where siphoning of CSF leads to overdrainage, which is then hypothesized to cause slit-ventricle syndrome in a small subset of patients. Our data suggests that while there have been numerous reports regarding overdrainage and its consequences, the evidence is not as robust as currently presumed and this subject requires prospective exploration.

Prevention of ventricular catheter obstruction and slit ventricle syndrome by the prophylactic use of the Integra antisiphon device in shunt therapy for pediatric hypertensive hydrocephalus: a 25-year follow-up study

OBJECT

This 25-year follow-up study was performed on 120 children with hypertensive hydrocephalus to evaluate the influence of the early prophylactic implantation of the Integra antisiphon device (ASD, Integra Neurosciences Ltd.) on the rate of proximal shunt obstructions and the frequency of symptomatic slit ventricle syndrome (SVS). The adaptability of the ASD to growth, proper positioning of the ASD as a necessity for its successful performance, and the 3 phases of SVS development are discussed.

METHOD

Since 1978, the ASD has consistently been implanted either at the time of primary shunt insertion (66 neonates, mean follow-up 11 years) or during revisions of preexisting shunts (54 children, mean follow-up 11.8 years). The complication rate among the 54 children before ASD implantation (mean follow-up 8.3 years) was compared with that among all 120 patients once an ASD had been inserted. Shunt complications were documented as ventricular catheter, distal catheter, and infectious complications.

RESULTS

The study revealed a significant long-term reduction in ventricular catheter obstructions and hospitalizations due to intermittent intracranial hypertension symptoms (symptomatic SVS) after both primary and secondary ASD implantation. Data in the study suggest that the high rate of ventricular catheter obstruction in pediatric shunt therapy is caused by hydrostatic suction induced by differential-pressure valve shunts during mobilization of the patient and that the development of a SVS can be traced back to this constant suction, which causes chronic CSF overdrainage and ventricular noncompliance. Recurrent ventricular catheter obstruction and SVS can be prevented by prophylactic supplementation of every shunt system with an ASD.

CONCLUSIONS

To inhibit chronic hydrostatic suction, to prevent overdrainage and proximal shunt obstruction, and to avoid SVS and thus improve the patient's quality of life, the prophylactic implantation of an ASD in every pediatric hydrocephalus shunt is recommended.

Surgical management of adult hydrocephalus

The management of adult hydrocephalus spans a broad range of disorders and ages. Modern management strategies include endoscopic and adjustable cerebrospinal fluid shunt diversionary techniques. The assessment and management of the following clinical conditions are discussed: 1) the adult patient with congenital or childhood-onset hydrocephalus, 2) adult slit ventricle syndrome, 3) multicompartmental hydrocephalus, 4) noncommunicating hydrocephalus, 5) communicating hydrocephalus, 6) normal pressure hydrocephalus, and 7) the shunted patient with headaches. The hydrodynamics of cerebrospinal fluid shunt diversion are discussed in relation to mechanisms of under- and overdrainage conditions. A rationale for the routine implementation of adjustable valves for adult patients with hydrocephalus is provided based on objective clinical and experimental data. For the condition of normal pressure hydrocephalus, recommendations are offered regarding the evaluation, surgical treatment, and postoperative management of this disorder.

Microsurgical third ventriculocisternostomy as an alternative to ETV: report of two cases

OBJECTIVE

To describe a microsurgical alternative to endoscopic third ventriculocisternostomy.

METHODS

Two children with shunt-dependent hydrocephalus and multiple shunt revisions were considered candidates for third ventriculocisternostomy (TVS). Because of slit ventricles, an endoscopic approach was not possible and, therefore, both patients received a microsurgical TVS by a supraorbital approach.

RESULTS

In both cases, microsurgical TVS was successful and the patients became shunt free.

CONCLUSION

Microsurgical TVS by a supraorbital craniotomy is a viable alternative to endoscopic TVS in selected cases.

Valve pressure upgrade may produce progressive deterioration of vision in children with slit ventricle syndrome

Recently, valve upgrade and/or endoscopic third ventriculostomy, which have the merit of no additional shunting, were introduced for the treatment of slit ventricle syndrome, because lumboperitoneal shunting entails various complications including development of Chiari malformation, shunt malfunction, and infection. However, the safety of valve upgrading is not confirmed, especially in a child with slit ventricle syndrome developed as a result of pseudotumor cerebri. A 5-year-old boy with pseudotumor cerebri presented with headache, intermittent vomiting, and sudden deterioration of visual acuity. His cerebrospinal pressure during lumbar puncture was 69 cm H(2)O and his magnetic resonance imaging revealed only small ventricles. He underwent a ventriculoperitoneal shunt resulting in dramatic improvement. Four months later, he returned with recurrent spontaneous valve malfunction with recurrent severe headache and visual deterioration. After shunt revision with a programmable valve, his intermittent valve malfunction was improved by upgrading the valve opening pressure. However, his visual acuity became progressively aggravated. He underwent a lumboperitoneal shunt with low-pressure valve, which resulted in the disappearance of intermittent headaches and a deterioration of visual acuity. We suggest that valve pressure upgrade in children with slit ventricle syndrome after ventriculoperitoneal shunt for pseudotumor cerebri may produce acute deterioration of vision that had already been compromised, even within the normal intracranial pressure range and with improvement of associated symptoms.

Endoscopic third ventriculostomy in the treatment of shunt-related over-drainage: Preliminary experience with a new approach how to render ventricles navigable

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is increasingly used for the treatment of shunt-related complications in hydrocephalic patients, particularly if the etiology of the underlying hydrocephalus is of obstructive nature.

PURPOSE

Due to the slit-like configuration of the ventricles, ventricular dilatation must be achieved prior to ETV in patients with problems due to over-drainage. This has been accomplished by ligating or explanting the shunt. Here we present an alternative procedure using a gravitational antisiphon device.

MATERIALS AND METHODS

In two patients with over-drainage due to shunted occlusive hydrocephalus ventricles were dilated by integrating an antisiphon device (Miethke ShuntAssistant, Aesculap AG, Tuttlingen, Germany) into their shunt systems. The resistance of the antisiphon device, which is available in configurations from 10 to 35 cm H2O was chosen 10 cm H2O higher than necessary to prevent siphoning in the individual patient.

RESULTS

Both patients gradually recovered from their over-drainage symptoms and the ventricles enlarged enough to allow access with an endoscope. Using a standard procedure, ETV was performed 7 days and 1 month later, respectively. In the same operative session the shunts were occluded. Shunts were removed within 6 weeks after ETV. During follow-up of more than 3 years, both patients remained free of symptoms.

CONCLUSION

The incorporation of an antisiphon device with resistance level selected 10 cm H2O higher than needed to prevent anti-siphoning into a pre-existing shunt system in patients suffering from shunt-related over-drainage is a safe and effective technique to render ventricles large enough to allow endoscopic access for ETV.

The role of cranial expansion for craniocephalic disproportion

The appropriate treatment for craniocephalic disproportion, such as caused by slit ventricle syndrome, is uncertain. We have reviewed the treatment and outcomes of 4 children who underwent cranial expansion over a period of 5 years. The ages at cranial expansion were 16 months, 3 years 6 months and 2 at 6 years. Two children had slit ventricle syndrome and were treated with bilateral parietal expansions. Two children had non-syndromic craniosynostosis, one of these having vitamin D-resistant rickets. The latter 2 were treated with posterior cranial vault expansion, and one also had a craniocervical junction decompression performed. Post-operatively, symptoms of raised intracranial pressure resolved in all cases, and there was radiological evidence of re-establishment of normal CSF pathways. Although a rare condition, cranial expansion operations can be successful in appropriately selected cases of craniocephalic disproportion.

The problematic slit ventricle syndrome. A review of the literature and proposed algorithm for treatment

This review discusses the clinical difficulties with the so-called slit ventricle syndrome. It discusses why this terminology makes it difficult to formulate treatment algorithms. Slit ventricle syndrome should probably be known as the non-compliant ventricle syndrome to avoid confusion of radiological 'slit ventricles' with the syndrome. Therapeutic measures should ideally focus on the underlying pathology related to the syndrome. For those patients with iatrogenic small calvaria and synostosis, subtemporal decompression would appear a low-risk and quick procedure. Calvarial expansion would be a second-line treatment. For those patients with a normal-sized calvarium and non-compliant ventricle syndrome, valve upgrade, adding an antisiphon device or programmable valve would appear a good first step. For patients in whom the diagnosis is unclear, a potential management plan is discussed.