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

Vaulting further: cranial vault expansion for craniocerebral disproportion without primary craniosynostosis

PURPOSE

Treatment of subjects with refractory idiopathic intracranial hypertension (IIH) or shunted hydrocephalus with chronic shunt complications is challenging. What is the role for cranial vault expansion, particularly utilizing posterior vault distraction osteogenesis (PVDO), in these cases? This study assesses medium-term efficacy of cranial vault expansion in this unique patient population.

METHODS

A retrospective review was conducted of patients who underwent cranial vault expansion from 2008 to 2023 at the Children's Hospital of Philadelphia. Subjects who did not have a diagnosis of primary craniosynostosis were included in the study. Demographic information, medical history, and perioperative details were collected from medical records. Primary outcomes were the rate of CSF diversion procedures and resolution of presenting signs and symptoms. Secondary outcomes were perioperative and 90-day complications and reoperation requirement.

RESULTS

Among 13 included subjects, nine (69.2%) patients had a primary diagnosis of shunted hydrocephalus and 4 (30.8%) patients had IIH. Twelve (92.3%) subjects underwent posterior vault distraction osteogenesis (PVDO) and one (7.7%) underwent posterior vault remodeling (PVR). All 4 patients with IIH demonstrated symptomatic improvement following PVDO, including resolution of headaches, vomiting, and/or papilledema. Among 9 patients with shunted hydrocephalus, CSF diversion requirement decreased from 2.7 ± 1.6 procedures per year preoperatively to 1.2 ± 1.8 per year following cranial vault expansion (p = 0.030). The mean postoperative follow-up was 4.1 ± 2.1 years and four (30.8%) patients experienced complications within 90 days of surgery, including infection (n = 2), CSF leak (n = 1), and elevated ICP requiring lumbar puncture (n = 1). Four (30.8%) patients underwent repeat cranial vault expansion for recurrence of ICP-related symptoms. At most recent follow-up, 7 of 9 patients with shunted hydrocephalus demonstrated symptomatic improvement.

CONCLUSION

Cranial vault expansion reduced intracranial hypertension-related symptomology as well as the rate of CSF diversion-related procedures in patients with refractory IIH and shunted hydrocephalus without craniosynostosis, and should be considered in those who have significant shunt morbidity.

Effectiveness of subtemporal decompression for the management of slit ventricle syndrome

OBJECTIVES

To assess the effectiveness of subtemporal decompression in the management of slit ventricle syndrome.

METHODS

We conducted a retrospective review of all patients with slit ventricle syndrome (SVS) who underwent subtemporal decompression (STD) at our centre between 2010 and 2021. Cases were identified using the hospital database. Medical records for each patient were reviewed, including operative and radiological reports.

RESULTS

Fifteen patients underwent STD for the management of SVS. Median age at time of STD was 9.18 years. Aetiology of hydrocephalus consisted of spinal dysraphism (5), idiopathic (4), post-infectious (1), post-haemorrhagic (3), secondary to tumour (1), and craniofacial anomalies (1). Median age at first shunt insertion was 3.4 months. Median pre-operative period assessed, from initial shunt insertion to STD, was 4.54 (interquartile range [IQR] 3.12-10.47) years. Twelve patients underwent ≥1 shunt revision prior to STD. All patients had a diagnosis of SVS at time of STD. Presenting symptoms, for the admission in which STD was performed, included nausea (9), vomiting (8), lethargy (8), headache (12), irritability (5), and visual disturbances (6). One third underwent shunt revision at the time of STD. Two patients developed post-operative complications requiring further surgery (meningitis requiring shunt revision: 1; wound debridement: 1). Three patients developed uncomplicated post-operative pyrexia, which was managed with antibiotics. Median duration of post-operative follow-up was 5.4 (IQR 1.73-8.54) years. Eleven patients underwent ≥1 shunt related procedure following STD. Wilcoxon signed-rank test demonstrated a significant difference in number of shunt related procedures before (median = 5, IQR 1-8) and after (median = 3, IQR 0-5) STD (Z = -2.083, p = .037). All patients reported subjective symptom improvement post-operatively. Thirteen patients experienced symptom recurrence at a median duration of 10 months post-operatively.

CONCLUSIONS

STD was associated with a reduction in the amount of shunt related procedures required in this group of patients with SVS. Further study is required to confirm this association.

External-internal cranial expansion to treat patients with craniocerebral disproportion due to post-shunt craniosynostosis: a case series

INTRODUCTION

Secondary craniosynostosis subsequent to shunting is one of the late complications of ventricular shunt placement in the early childhood. Several interventions have been used to treat high intracranial pressure associated with this condition. This study aimed to evaluate the patients' clinical symptoms and head circumference before and after a method of decompressive craniotomy, coined as external-internal cranial expansion (EICE).

METHODS

A retrospective study was conducted, and the patients who had undergone EICE for the treatment of post-shunt craniosynostosis between 2010 and 2020 were enrolled. This approach was a combination of a hinge multiple-strut decompressive craniectomy and internal cranial flap thinning by drill. Data, extracted from medical records, were used to evaluate the patients' symptoms and head circumferences before and 12 months after surgery.

RESULTS

A total of 16 patients were enrolled in the study, of which eight were females. Before the surgery, 9 patients (56.2%) suffered from visual impairment, and all had intractable headache. Papilledema was recorded in all, with 3 cases having optic disc paleness. After cranial expansion, only two patients had headaches, diagnosed as migraine-type and psychosomatic headaches, respectively. In two patients, progressive visual impairments got worsening after surgery, which would be due to severe preoperative optic nerve atrophy. Patients' head circumferences significantly increased after the surgery (mean of 48.97 ± 4.28 cm vs. 45.78 ± 4.31 cm; P value < 0.0001).

CONCLUSION

In lower resource countries, where newer technologies like distraction osteogenesis is not easily available, external-internal cranial expansion can be considered an effective alternative for patients with post-shunt craniosynostosis.

Cerebral venous sinus thrombosis as a consequence of shunt hyperdrainage: a proposal of the pathophysiological mechanism and case report

BACKGROUND AND AIM

Shunt dysfunction is a common event, especially in children who have this intervention performed early in life. The consequences of chronic shunt overdrainage can be multiple since the cerebral hydrodynamics is altered. A thrombotic event with consequent symptoms of intracranial hypertension is discussed in this article.

MATERIAL AND METHODS

We performed a detailed review of cerebral hydrodynamics and intracranial pressure compensation mechanisms and how this can alter cerebral venous circulation. Next, we report the case of a 4-year-old child with such a clinical presentation that was conducted by our team.

RESULTS

A child with a history of hydrocephalus treated with a ventriculo-peritoneal (VP) shunt in his early childhood presented with symptoms of intracranial hypertension, initial computed tomography (CT) demonstrating reduced-sized ventricles. Complementary investigation showed bilateral papilledema, cranial suture closure, changes compatible with Chiari type I, and venous sinus thrombosis (transverse and sigmoid, bilaterally). The case was managed conservatively with full anticoagulation with enoxaparin. Four months after the onset of symptoms, there was an improvement in the clinical and imaging status.

CONCLUSION

A condition of severe headache in a patient with an apparently functioning shunt and small ventricles on initial CT should open up a range of diagnostic possibilities, with pseudotumor cerebri syndrome and cerebral venous sinus thrombosis being suggested. The therapeutic approach in these cases must be individualized.

Risk factors for unchanged ventricles during pediatric shunt malfunction

OBJECTIVE

Children whose ventricles do not change during shunt malfunction present a diagnostic dilemma. This study was performed to identify risk factors for unchanged ventricular size at shunt malfunction.

METHODS

This retrospective 1:1 age-matched case-control study identified children with shunted hydrocephalus who underwent shunt revision with intraoperative evidence of malfunction at one of the three participating institutions from 1997 to 2019. Cases were defined as patients with a change of < 0.05 in the frontal-occipital horn ratio (FOR) between malfunction and baseline, and controls included patients with FOR changes ≥ 0.05. The presence of infection, abdominal pseudocyst, pseudomeningocele, or wound drainage and lack of baseline cranial imaging at the time of malfunction warranted exclusion.

RESULTS

Of 450 included patients, 60% were male, 73% were Caucasian, and 67% had an occipital shunt. The median age was 4.3 (IQR 0.97-9.21) years at malfunction. On univariable analysis, unchanged ventricles at malfunction were associated with a frontal shunt (41% vs 28%, p < 0.001), programmable valve (17% vs 9%, p = 0.011), nonsiphoning shunt (85% vs 66%, p < 0.001), larger baseline FOR (0.44 ± 0.12 vs 0.38 ± 0.11, p < 0.001), no prior shunt infection (87% vs 76%, p = 0.003), and no prior shunt revisions (68% vs 52%, p < 0.001). On multivariable analysis with collinear variables removed, patients with a frontal shunt (OR 1.67, 95% CI 1.08-2.70, p = 0.037), programmable valve (OR 2.63, 95% CI 1.32-5.26, p = 0.007), nonsiphoning shunt at malfunction (OR 2.76, 95% CI 1.63-4.67, p < 0.001), larger baseline FOR (OR 3.13, 95% CI 2.21-4.43, p < 0.001), and no prior shunt infection (OR 2.34, 95% CI 1.27-4.30, p = 0.007) were more likely to have unchanged ventricles at malfunction.

CONCLUSIONS

In a multicenter cohort of children with shunt malfunction, those with a frontal shunt, programmable valve, nonsiphoning shunt, baseline large ventricles, and no prior shunt infection were more likely than others to have unchanged ventricles at shunt failure.

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.

The Expanding Role of Posterior Vault Distraction Osteogenesis in Idiopathic Intracranial Hypertension and Slit Ventricle Syndrome

ABSTRACT

The purpose of this study was to compare perioperative safety and efficacy of posterior vault distraction osteogenesis (PVDO) in patients with primary nonsynostotic cephalo-cranial disproportion, namely slit ventricle syndrome and idiopathic intracranial hypertension (IIH), to a cohort of patients with craniosynostosis (CS). A retrospective review of patients undergoing PVDO from 2009 to 2019 at our institution was performed. Craniosynostosis patients were matched by sex and age at PVDO to the nonsynostotic cohort. Operative details, perioperative outcomes, and distraction patterns were analyzed with appropriate statistics. Nine patients met inclusion criteria for the non-CS cohort. Six patients (67%) underwent PVDO for slit ventricle and the remaining 3 patients (33%) underwent PVDO for IIH. The majority of CS patients were syndromic (n = 6, 67%) and had multisuture synostosis (n = 7, 78%). The non-CS cohort underwent PVDO at a median 56.1 months old [Q1 41.1, Q3 86.6] versus the CS cohort at 55.7 months [Q1 39.6, Q3 76.0] (P = 0.931). Total hospital length of stay was longer in the non-CS patients (median days 5 [Q1 4, Q3 6] versus 3 [Q1 3, Q3 4], P = 0.021). Non-CS patients with ventriculoperitoneal shunts had significantly less shunt operations for ICP concerns post-PVDO (median rate: 1.74/year [Q1 1.30, Q3 3.00] versus median: 0.18/year [Q1 0.0, Q3 0.7]; P = 0.046). In this pilot study using PVDO to treat slit ventricle syndrome and IIH, safety appears similar to PVDO in the synostotic setting. The cohort lacks adequate follow-up to assess long term efficacy, although short-midterm follow-up demonstrates promising results with less need for shunt revision and symptomatic relief. Future studies are warranted to identify the preferred surgical approach in these complex patients.

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.

Bridging the intracranial pressure gap: a smooth transition strategy for slit ventricle syndrome

Slit ventricle syndrome (SVS) is a well-known complication of long-standing shunts. Patients develop intermittent severe headache, vomiting with other symptoms of increased intra-cranial pressure. Brain computed tomography (CT) usually reveals slit-like ventricles with nearly obstructed proximal catheters. Treatment for SVS usually involves upgrading the shunt valve pressure setting. Currently, many patients carry programmable shunts and pressure setting can be adjusted noninvasively. However, when the programmable valve pressure setting is upgraded, some patients with SVS experience worsened symptoms. This is caused by the time gap between ICP increase and real ventricular expansion (and freeing proximal catheter) after shunt upgrading. Therefore, it is important to control a patient's symptoms during the transition period. We report our experience in controlling ICP in a patient with SVS using external ventricular drainage.

Decompressive Cranial Vault Remodeling in Osteosclerotic Robinow Syndrome

We present a novel application of endocranial burr contouring for cranial vault expansion as a surgical adjunct during decompressive craniectomy in patients with cranial osteosclerosis. A 16-year-old female with osteosclerotic Robinow syndrome complicated by slit ventricle syndrome presented with refractory intracranial hypertension following external ventricular drain placement. Symptoms included severe headaches and altered mental status. Given the severe intracranial volume restriction secondary to massive calvarial thickening (2.5 cm), the patient was taken to the operating room for urgent surgical decompression. After frontal and parietal craniectomy, burr and osteotome contouring were used to remove two-thirds of the endocranial calvarial bone flap thickness resulting in a 9% cranial vault expansion while preserving an overall normal head size. There were no immediate postoperative complications. At over 3 years postoperatively, the patient had reduced headaches, maintained adequate shunt function, and has not required further vault reconstruction.

Shunt Failure-The First 30 Days

BACKGROUND

Incontrovertible predictors of shunt malfunction remain elusive.

OBJECTIVE

To determine predictors of shunt failure within 30 d of index surgery.

METHODS

This was a single-center retrospective cohort study from January 2010 through November 2016. Using a ventricular shunt surgery research database, clinical and procedural variables were procured. An "index surgery" was defined as implantation of a new shunt or revision or augmentation of an existing shunt system. The primary outcome was shunt failure of any kind within the first 30 days of index surgery. Bivariate models were created, followed by a final multivariable logistic regression model using a backward-forward selection procedure.

RESULTS

Our dataset contained 655 unique patients with a total of 1206 operations. The median age for the cohort at the time of first shunt surgery was 4.6 yr (range, 0-28; first and third quartile, .37 and 11.8, respectively). The 30-day failure rates were 12.4% when analyzing the first-index operation only (81/655), and 15.7% when analyzing all-index operations (189/1206). Small or slit ventricles at the time of index surgery and prior ventricular shunt operations were found to be significant covariates in both the "first-index" (P < .01 and P = .05, respectively) and "all-index" (P = .02 and P < .01, respectively) multivariable models. Intraventricular hemorrhage at the time of index surgery was an additional predictor in the all-index model (P = .01).

CONCLUSION

This study demonstrates that only 3 variables are predictive of 30-day shunt failure when following established variable selection procedures, 2 of which are potentially under direct control of the surgeon.

Isolated Post-Shunt Metopic Synostosis and Neural Tube Defects

BACKGROUND

Craniosynostosis is an uncommon complication after shunting procedures for congenital hydrocephalus. We report a case of a child with myelomeningocele and normocephaly at the time of birth. She underwent ventricular shunting for Chiari malformation and hydrocephalus at 3 days of age. An immediate postoperative CT scan confirmed all sutures were open. Serial CT scans document an open metopic suture at 2 months, closed metopic suture at 5 months, and trigonocephaly at 11 months with concomitant slit ventricle syndrome, and collapsed lateral and third ventricles.

METHODS

An Ovid MEDLINE search within the dates of 1948 through 2017, using the keywords "synostosis AND shunt" was carried out. A tabulation of all patients and their respective synostosis patterns were recorded.

RESULTS

We identified 8 case series and 2 case reports during 43 years (1966-2017). Seventy-eight patients with 79 suture synostosis patterns were identified (one patient underwent a second cranial reconstruction for identification of a separate, newly formed synostosis). Eighteen (30.5%) cases were associated with a neural tube defect (NTD). Patients with NTD and secondary craniosynostosis had on average earlier age of shunt placement (P = 0.001), craniosynostosis presentation (P = 0.146), and cranioplasty (P = 0.325) than secondary craniosynostosis patients without NTD.

CONCLUSIONS

Ventricular shunt drainage in treating hydrocephalus rarely may lead to early synostosis and cranial deformity, especially in patients with NTDs. Early shunt placement poses significant risk in patients with NTD. Close follow-up may be necessary to evaluate overdrainage and cranial deformity after shunting procedures.

The Neuroimaging Studies in Children with Ventriculoperitoneal Shunt Complications: A 10 Years Descriptive Sudy in Tehran

Background

Any mismatch between the production and absorption of CSF results in hydrocephalus. In most cases, the selected choice of treatment is the ventriculoperitoneal shunt insertion. Although, the surgery could have complications such as infection, shunt malfunction, subdural hematoma, seizure and Shunt immigration; so, the early and proper detection of these complications could result in better prognosis. The aim of this study was to evaluate and compare the efficacy of CT scan, CSF analysis and X-ray radiography in detection of shunt complications and problems in shunt placement and further follow-up in hospitalized children.

Methods

The medical records of children in Rasul Akram hospital in Tehran were reviewed retrospectively in the last 10 years, from 2006 to 2016. All data were recorded in the prepared form including the age, sex, shunt complication, CT scan and CSF characteristics.

Results

The total number of 95 patients were interfered in this study including 56 males (58.9%) and 39 females (41.1%). The mean age at the onset of complications were 2.8±2.2 years-old. The shunt obstruction (60%) and infection (25.3%) were the most common complications. The CT scan was able to detect 36.5% of shunt complications. The CT scan had the sensitivity and specificity of 50 and 87%, respectively in detection of shunt obstruction. The all cases of brain hematoma and hemorrhage were revealed by CT scan. On the other hand, the CT scan had 20% of sensitivity and 60% of specificity in the detection of shunt infection. The CSF evaluation in shunt infection revealed 92% hypoglycemia, 87.5% pleocytosis, and 62.5% positive CSF culture. CSF had the sensitivity, specificity, positive predictive value and negative predictive value of 92, 82, 63 and 97%, respectively. The patient's symptoms and signs were helpful in obtaining higher test accuracy.

Conclusion

The CT scan was not a good sensitive and specific study in the detection of shunt obstruction and infection, but it was very accurate in detection of hemorrhage and hematoma. On the other hand, CSF evaluation was a reliable test in shunt infection disclosure.

[Semiology of ventriculoperitoneal shunting dysfunction in children - a review]

INTRODUCTION

Ventriculoperitoneal shunting (VPS) is a treatment of the hydrocephalus that may dysfunction. The clinical presentation of shunt dysfunction is variable. We therefore decided to focus on the clinical presentation of VPS malfunction in children, as this condition requires immediate emergency treatment and because of the sometimes confusing signs of intracranial hypertension in a shunted child.

MATERIALS AND METHODS

We searched PubMed with the following groups of keywords: (dysfunction OR blockage) AND shunting AND hydrocephalus; shunt complications AND hydrocephalus; hydrocephalus AND shunt AND malfunction. Articles dealing with ventriculo-atrial shunt were excluded. A total of 79 articles were retained for analysis (English and French). Case reports were excluded.

RESULTS

The clinical presentation varies by age: vomiting and alterated level of consciousness are the most frequent signs in older children, whereas infants present more often with raised intracranial pressure symptoms such as nausea, vomiting, irritability and bulging fontanel. Drowsiness is a good predictor of VPS dysfunction. An asymptomatic presentation is rare but possible. Abdominal presentation is also possible, ranging from abdominal discomfort to peritonitis. Fever, occurring a short time after the last intervention, and irritability are good predictors of shunt infection. Pumping the chamber of the VPS has a weak positive predictive value (12%). Shunt dysfunction can lead to death, with an estimated mortality rate at 1% per year during the first years.

CONCLUSION

It is essential to be aware of the variability of the clinical presentation of VPS dysfunction, because of the potential severity of this condition. Also it is important to pay attention to the comments of the parents, especially if the child experienced a previous shunt malfunction.

Cranial vault expansion with the split bone flap technique in shunt-related craniosynostosis

INTRODUCTION

Shunt-related craniosynostosis causing craniocerebral disproportion represents a particular complication of the treatment of hydrocephalus. When the modification of the shunt opening pressure does not improve the symptomatology, surgery for correction of craniocerebral disproportion is indicated. We present the results and advantages of the split bi-frontal bone technique that is a modification of the previous used frontal bone advancement technique.

PATIENTS AND METHODS

We retrospectively reviewed 5 patients with iatrogenic craniosynostosis treated in our institution from 1995 to 2012. A splitting bi-frontal bone flap that is left floating posteriorly was performed to increase the cranial volume.

RESULTS

All patients were cured. This technique increases the volume of the skull favoring the expansion of the brain and allows good cosmetical results. No perioperative complications were reported.

DISCUSSION

The fact that the brain has a more appropriate volume allows the disappearance of the clinical symptomatology related to the split ventricle syndrome. The advantage is the respect of the fronto-orbital shape in children and adults with the same results of the classic frontal advancement in terms of volume expansion. The study of cerebral blood flow confirms the increase of the cerebral blood perfusion and the improvement of the regional cerebral blood flow in borderline regions. We preconize, for the treatment of slit ventricle syndrome, the bi-frontal split technique in children and adults for its efficacy, the low rate of complications and the respect of aesthetical constraints.

Slit ventricle syndrome and early-onset secondary craniosynostosis in an infant

Patient: Female, 14 months

Final Diagnosis: Slit ventricle syndrome

Symptoms: Hydrocephalus • lethargy and seizure • vomiting

Medication: —

Clinical Procedure: —

Specialty: Pediatrics and Neonatology

Imaging evaluation of CSF shunts

OBJECTIVE

The objective of this article is to describe an approach to imaging CSF shunts. Topics reviewed include the components and imaging appearances of the most common types of shunts and the utility of different imaging modalities for the evaluation of shunt failure. Complications discussed include mechanical failure, infection, ventricular loculation, overdrainage, and unique complications related to each shunt type.

CONCLUSION

This article reviews the imaging features of common CSF shunts and related complications with which radiologists should be familiar.

Craniocerebral disproportion: a topical review and proposal toward a new definition, diagnosis, and treatment protocol

INTRODUCTION

At some point in their lives, patients previously shunted for hydrocephalus may experience chronic, debilitating headaches, despite the fact that their shunts are functioning properly. Previously published reports have suggested that a subset of these patients may be suffering from an iatrogenic craniocerebral disproportion (CCD) and, therefore, may benefit from procedures that expand the available intracranial space. A unified definition of this disorder, however, is lacking.

DISCUSSION

Here, the authors chart the history (including historical terminology) of CCD, review its incidence, describe its signs, symptoms, and associated radiologic findings, and expound upon its pathophysiology. Next, a concise clinical definition of CCD based on the temporal correlation of headaches with the appearance of plateau waves on intracranial pressure (ICP) monitoring is proposed. The authors conclude with a discussion of the various therapeutic strategies employed previously to treat this disorder and present their individualized treatment strategy based upon the simultaneous utilization of ICP monitors and gradual external cranial vault expansion.

Slit ventricle syndrome: a case report of intermittent intracranial hypertension

Slit ventricle syndrome is a rare condition whereby brain compliance is reduced and can be associated with intermittent intracranial hypertension. A 19-year-old male with a ventriculoperitoneal shunt for congenital hydrocephalus presented with a 1-day history of headache and drowsiness-symptoms from which he suffered in many recurrent episodes over the past 5 years. The improvement of headaches without surgical intervention led to the diagnosis of migraine. During this hospitalization, episodes of intermittent intracranial hypertension were documented along with the remission and relapse of the symptoms. While the patient's intracranial pressure was within normal range in over 90% of his monitoring period, which postponed shunting, replacement of his ventriculoperitoneal shut eventually resolved his symptoms. Slit ventricle syndrome with reduced ventricular compliances should be considered in patients with clinical evidence of intermittent intracranial hypertension and small ventricular size. The authors advocate shunt replacement as an appropriate treatment for this condition.

Combined intracranial pressure monitoring and cerebrospinal fluid infusion study to guide management of slit ventricle syndrome

INTRODUCTION

Slit ventricle syndrome remains a complex entity presenting a considerable challenge to treat successfully. This study aims to demonstrate the application of dual intracranial pressure (ICP) and infusion studies together with the novel shunt occlusion test in both a diagnostic and therapeutic role.

CASE REPORT

An 8-year-old child had aqueduct stenosis treated with a ventriculoperitoneal shunt (medium-pressure valve). The presentation was of headaches with papilloedema. Imaging with both computed tomography and magnetic resonance imaging revealed slit ventricles. Initially a shunt exploration revealed distal obstruction that was treated together with insertion of a paediatric strata II regular valve; however, the child continued to deteriorate. Overnight ICP monitoring revealed dramatically raised ICP with poor compensatory reserve. Intra-operative infusion study revealed a shunt that was patent distally but with proximal obstruction. A subtemporal decompression ipsilateral to the shunt was performed together with adjustment of the paediatric strata II regular valve to 2.5 in order to prevent overdrainage. This led to normalisation of ICP, resolution of papilloedema and symptomatic improvement.

DISCUSSION

We demonstrate how combined ICP monitoring and shunt infusion studies can be used to help guide management. Unilateral subtemporal decompressions and preventing shunt overdrainage can result in normalisation of ICP and cerebrospinal fluid dynamics.

Treatment of cephalocranial disproportion in shunt-induced slit ventricle syndrome with cranial vault distraction osteogenesis

BACKGROUND

Slit ventricle syndrome (SVS) is a known late complication of shunting procedures. Some patients develop cephalocranial disproportion (CCD) that will require surgical treatment to increase craniocerebral compliance.

METHODS

We performed cranial vault distraction osteogenesis to treat 2 teenage patients who presented with SVS, increased intracranial pressure and CCD. Bilateral temporo-parieto-occipital craniotomies were performed.

RESULTS

Both patients successfully completed distraction and consolidated without the need for bone grafting. Postoperatively, both patients showed an increase in intracranial and intraventricular volume, as well as decreased shunt revisions. One patient had improvement of her headaches, while the other continues to have chronic headaches.

CONCLUSION

Distraction osteogenesis is an option to expand the cranial vault in older children with SVS and CCD, in which the traditional cranial vault expansion would be a challenge and may or may not provide adequate expansion.

Development of intracranial hypertension after surgical management of intracranial arachnoid cyst: report of three cases and review of the literature

OBJECTIVE

To describe three cases of delayed development of intracranial hypertension (IH) after surgical treatment of intracranial arachnoid cyst, including the pathogenesis of IH and a review of the literature.

METHODS

A retrospective and prospective analysis of three male patients (two 18 years old and one 45 years old) was performed. All patients underwent surgical intervention for symptomatic intracranial arachnoid cyst in the form of fenestration of the cyst and a cystoperitoneal shunt.

RESULTS

All three patients presented at a later stage with new-onset headaches after the initial management of arachnoid cyst. Magnetic resonance imaging and magnetic resonance venography ruled out any intracranial vascular pathology. Lumbar puncture and intracranial pressure monitoring showed increased intracranial pressure suggestive of idiopathic IH. To manage IH, intracranial pressure monitoring, cystoperitoneal shunt, ventriculoperitoneal shunt, and lumboperitoneal shunt were performed.

CONCLUSIONS

The pathogenesis of delayed development of IH in this clinical setting is not clearly elucidated. When intracranial arachnoid cysts are treated, the possibility of future development of IH should be borne in mind. Delayed presentation with headaches in patients after treatment of intracranial arachnoid cysts should raise the possibility of IH.

Neuroimaging of ventriculoperitoneal shunt complications in children

The ventriculoperitoneal shunt is the mainstay of treatment for hydrocephalus. Despite its widespread use and safety record, it often malfunctions due to complications such as obstruction, breakage, migration and infection. This necessitates a systematic approach to diagnosing the etiology of shunt failure. Any evaluation should begin with an appraisal of the patient's symptoms. In acute malfunction, nausea, vomiting, irritability, seizures, headache, lethargy, coma and stupor are seen. In chronic malfunction, neuropsychological signs, feeding pattern changes, developmental delay, decline in school performance, headaches and increased head size are often seen. The next step in evaluation is a CT scan of the head to evaluate ventricular size. Prior imaging studies should be obtained for comparison; if the ventricles have enlarged over time, shunt malfunction is likely. If there is no such increase or dilation in the first place, other diagnoses are possible. However, "slit ventricle syndrome" should also be considered. When prior imaging is not available, pumping the reservoir, a radionuclide shuntogram, a shunt tap or even surgical exploration are options. The goals of this paper are to provide an algorithm for evaluating shunt malfunction and to illustrate the radiographic findings associated with shunt failure.

Experience with a gravitational valve in the management of symptomatic overdrainage in children with shunts

OBJECT

Symptomatic overdrainage in children with shunt-treated hydrocephalus represents one of the more difficult shunt-related diseases and may require repeated surgery. Gravity-assisted valve design has become a standard device to avoid overdrainage in many European pediatric hydrocephalus centers. However, the use of a gravitational valve for relieving symptoms associated with overdrainage has not yet been addressed. The goal of this study was to evaluate the effectiveness of a gravitational valve in the treatment of symptomatic overdrainage in children with shunts.

METHODS

Seventeen children with an adjustable shunt system and symptomatic overdrainage were treated by insertion of a gravitational valve. Clinical and radiological outcome were monitored for a minimum of 12 months after surgery.

RESULTS

Implantation of a gravitational valve resulted in either resolution (n = 12) or improvement (n = 5) of the symptoms. In 1 patient, symptoms remained almost unchanged and the gravitational valve had to be upgraded, resulting in resolution of the symptoms. During follow-up, the pressure setting of the adjustable differential pressure valve had to be changed in 7 patients.

CONCLUSIONS

The gravitational valve was effective in improving symptomatic overdrainage in the majority of patients in the present study. Because the ideal pressure setting for a given patient is hard to determine a priori, adjustable valve systems appear to be beneficial.

Dynamics of cerebrospinal fluid flow in slit ventricle syndrome

INTRODUCTION

Although slit ventricle syndrome (SVS) is identified as a serious complication in shunt-treated hydrocephalus, cerebral spinal fluid (CSF) flow via external ventricular drainage (EVD) or shunts in SVS have not been studied up to now.

MATERIAL AND METHODS

A new apparatus (LiquoGuard(®); Möller-Medical, Fulda, Germany) was used for EVD in a child with SVS. The LiquoGuard actively controls CSF drainage, based on intracranial pressure (ICP).

RESULTS

To achieve well-tolerated clinical conditions, an ICP level of 4 mmHg was necessary; realizable by drainage rates between 0 and 35 mL/h. Drainage rate variations typically occurred with repetitive time intervals of 2 h causing a "saw tooth" shaped CSF flow pattern throughout 24 h.

DISCUSSION

SVS seems to be characterized largely by quickly varying CSF drainage demands. Whether this is a general phenomenon or just true for this case has still to be studied and needs further clarification.

Acute cranial decompression in Meckel-Gruber syndrome and slit-ventricle syndrome with craniocephalic disproportion

Slit-ventricle syndrome (SVS) is characterized by headaches associated with subnormal ventricular size in patients with shunt-treated hydrocephalus. It commonly occurs in children who have had shunts placed at an early age and is diagnosed when computed tomography scans are carried out to investigate suspected shunt obstruction with an accompanying rise in intracranial pressure (ICP). Overdrainage of cerebrospinal fluid may additionally result in craniocephalic disproportion, potentially by dampening the normal expansile pulsations of the dura against the skull, which leads to craniostenosis. Management is controversial because many strategies have only short-term benefit, and surgical intervention is understandably often seen as a last resort.We present a case of a child with SVS and craniocephalic disproportion who was treated with urgent cranial expansion due to rising ICP. Intraoperative ICP monitoring demonstrates a rapid and sustained drop in ICP, and the patient made an uneventful return to his premorbid condition. We conclude that cranial vault expansion should be considered as an effective treatment for postshunt craniocephalic disproportion in patients with SVS.

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.

Evaluation of Strata NSC and Codman Hakim adjustable cerebrospinal fluid shunts and their corresponding antisiphon devices

OBJECT

The authors investigated and compared the in vitro characteristics of 2 CSF shunts, the Strata NSC and the Codman Hakim, and their corresponding antisiphon devices (ASDs).

METHODS

Six new CSF shunts and the corresponding ASDs for each model were tested in an automated, computerized experimental setup based on pressure regulation. Opening pressure accuracy, resistance, sensitivity to abdominal pressure, antisiphon effect, and the influence of different ASD positions were determined.

RESULTS

In general the shunts performed according to the manufacturers' specifications. However, at the lowest setting, the opening pressure of the Strata NSC was close to 0, and in the Codman Hakim shunt, it was higher than specified. The resistance in the Codman Hakim shunt (5.4 mm Hg/ml/min) was much higher than that in the Strata NSC (3.6 mm Hg/ml/min). Abdominal pressure affected opening pressure in both valves. Positioning the Strata ASD above or below the ventricular catheter tip resulted in higher and lower opening pressures, respectively, than when it was placed in line with the catheter. The positioning of the Codman Hakim ASD did not influence the opening pressure.

CONCLUSIONS

Both CSF shunts work properly, but at the lowest setting the opening pressure of the Strata NSC was near 0 and in the Codman Hakim it was twice the manufacturer's specifications. The resistance in the Strata NSC was below the normal physiological range, and in the Codman Hakim device it was in the lower range of normal. The ASD did not change the shunt characteristics in the lying position and therefore might not do so in children. If this is the case, then a shunt system with an integrated ASD could be implanted at the first shunt insertion, thus avoiding a second operation and the possibility of infection.

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.