Shunt Overdrainage Research Articles

Utility of very high-pressure valves in persistent symptomatic shunt overdrainage

IntroductionShunt overdrainage is one of the long-term complications associated with ventriculoperitoneal shunts. Treatment of refractory cases may require further upgrading of both the valve opening pressure and antisiphon device. The aim of this paper is to describe the results of this combination in a selected group of patients. MethodsRetrospective cohort study that included 18 pediatric patients between 2003-2022. Previous shunts were exchanged for the combination of a SOPHYSA Polaris® SPVA-300 valve and upgraded fixed or adjustable antigravitatory devices. The following variables were collected: etiology of the hydrocephalus, age at first shunt and type of valve, number of shunt revisions, other surgical procedures, age at inclusion, clinical and radiological outcomes, and follow-up time. A descriptive analysis was done with means, medians and ranges for quantitative variables; percentages and frequencies for the analysis of qualitative data. ResultsThe median age at first shunt was two months (0-67). The mean number of shunt revisions before inclusion was three. Shunt removal was attempted in seven patients without success; temporary success was observed in two patients who underwent ETV. Two patients had previous cranial expansions. The mean age at inclusion was 9.1 years (2.7-15.2). After the shunt system was exchanged and upgraded, clinical improvement was observed in 94.4% (17/18) of patients, and radiological improvement was observed in 83.3% (15/18) of patients. The median follow-up was 21 months. ConclusionsBefore considering more invasive therapeutic measures, shunt system optimization by the combination of very high-pressure valves and upgraded in-line antisiphon devices is a valid and safe strategy for refractory symptomatic shunt overdrainage.

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.

In Reply: Middle Meningeal Artery Embolization for Primary Treatment of a Chronic Subdural Hematoma in a Pediatric Patient: A Systematic Review of the Literature and Case Report.

To the Editor: We thank Lu et al1 for their interest in our article. Middle meningeal artery (MMA) embolization is becoming increasingly used in a subset of pediatric patients, and in the short time since the submission of our manuscript, an additional 2 case reports have been published.2,3 In their letter, Lu et al1 described several important considerations that will guide the selection of appropriate pediatric candidates for MMA embolization. Age—We agree that the age of the patient is an important factor. Among pediatric patients, chronic subdural hematomas are most commonly associated with abusive head trauma, anticoagulation/antiplatelet treatment for congenital cardiac disease, and ventricular shunt overdrainage.4 As a result, pediatric chronic subdural hematomas are often identified in infants and young children. Less common etiologies include neoplastic disease and arachnoid cysts, which can affect pediatric patients of any age. Pediatric patients at the younger end of the spectrum present several unique challenges because of the small caliber of their blood vessels, as well as the importance of limiting iodinated contrast and ionizing radiation.5 Despite these challenges, MMA embolization in young patients is feasible and can be a safe option in select patients when performed by experienced providers. Five of the 8 cases that have been described in the literature involved patients who were 2 years of age or younger.2,3,6-8 Etiology—As highlighted by Lu et al,1 2 patients in our systematic review underwent MMA embolization in the setting of a ruptured arachnoid cyst.9,10 We fully agree that subdural hygromas associated with arachnoid cysts can be treated nonsurgically11 and that even a certain subset of subdural hematomas can also be observed in this setting. As such, we agree that MMA embolization may not be the optimal first-line treatment in such cases. Indeed, both patients described in the literature only underwent MMA embolization after first undergoing either burr hole drainage or subdural-to-peritoneal shunt placement, with subsequent symptomatic recurrence of the hematoma.9,10 Timing—As alluded to above, the timing of intervention is controversial. Only 2 of the patients described in the literature underwent MMA embolization as a first-line treatment.7,12 Given the small number of cases that have been reported to date, we agree that MMA embolization is far from becoming the standard of care among pediatric patients with chronic subdural hematomas. Nevertheless, it represents yet another treatment option in the neurosurgeon's armamentarium and warrants additional study to determine its optimal role. We thank Lu et al1 for pointing out these important considerations and look forward to seeing the pediatric neurosurgical community continue to study the indications, efficacy, and risks of pediatric MMA embolization.

Pituitary enlargement in patients with cerebrospinal fluid drainage due to ventricular shunt insertion: know the condition and do not mistake for adenoma

ObjectiveChildhood hydrocephalus patients treated by ventriculo-peritoneal (v.-p.) shunting are sometimes referred years after this therapy for evaluation of suspicious pituitary enlargement. Since pituitary size has been shown to depend on cerebrospinal fluid (CSF) pressure, we assume this phenomenon to be caused by shunt overdrainage. Therefore, we studied pituitary size and morphology in shunted hydrocephalus patients with radiological signs of high CSF drainage.Patients and methodsRetrospective study of pituitary size and morphology in 15 shunted patients with non-tumoral hydrocephalus and 7 shunted hydrocephalus patients due to childhood brain tumor compared to a population mean. In five brain tumor patients also pre- and postsurgical comparisons were performed.ResultsPituitary mid-sagittal size and pituitary volume were significantly higher in both hydrocephalus groups, compared to the population mean (midsagittal size t = 5.91; p < 0.001; pituitary volume, t = 3.03; p = 0.006). In patients available for pre- and postoperative comparison, there was also a significant increase in pituitary size and volume postoperatively (mean preoperative midsagittal height 2.54 ± 1.0 mm vs. 6.6 ± 0.7 mm post-surgery; mean pre-operative pituitary volume 120.5 ± 69.2 mm3 vs. 368.9 ± 57.9 mm3 post-surgery).ConclusionOur results confirmed a significant increase in pituitary size and volume, mimicking pituitary pathology, after v.-p. shunt insertion. This phenomenon can be explained by the Monro–Kellie doctrine, stating that intracranial depletion of CSF—as caused by v.p. shunting—leads to compensatory intracranial hyperemia, especially in the venous system, with the consequence of engorged venous sinuses, most likely responsible for enlargement of the pituitary gland.

DDEL-03. The use of programmable valves as a vehicle for intrathecal chemotherapy delivery in infants with CNS tumors and hydrocephalus.

INTRODUCTION: Current chemotherapy protocols for treatment of embryonal brain tumors in infants recommend administration of intrathecal chemotherapy either by a lumbar tap or via an Ommaya reservoir. Children with concurrent hydrocephalus and shunts may have sub-therapeutic levels of chemotherapy in the CSF due to constant CSF drainage to extra-CNS compartments. We present our experience in delivery of chemotherapy to young children via programmable valves. RESULTS: A retrospective analysis of infants with CNS malignancies and hydrocephalus treated with a shunt and a programmable valve (CERTAS™ Plus Programmable Valves - Integra Life Sciences) was conducted. Five infants 1.1-3 years of age (mean 2) were included. Pathologies included atypical teratoid rhabdoid tumor (ATRT N=2), medulloblastoma (N=2), and metastatic rhabdomyosarcoma(N=1). Intrathecal injections were conducted in an outpatient setting unless hospitalization was required for other reasons. Only one child required sedation due to noncompliance. A total of 61 chemotherapeutic administrations were performed directly through the valve while set on an extremely high opening pressure for several hours( 35 with hydrocortisone and cytarabine, 26 with topotecan). There were no infections, leaks or major complications. One child required a wound revision due to exposure of the proximal catheter related to extremely thin skin, one child developed somnolence and fever which were not related to a shunt malfunction or infection, and one child had clinical and radiological shunt over-drainage solved by increasing of valve settings. CONCLUSIONS: Programmable ventriculoperitoneal valves appear to a safe method for delivery of chemotherapy in infants with malignant CNS tumors .This technique may potentially have an added value for children with concurrent shunts, and may also obviate the need for an additional ventricular access device .

Shunt Over-drainage, Slit Ventricle Syndrome, Programmable Valves and Anti-Siphon Devices. A Narrative Review of a Multifactorial and Intractable Problem.

The current management strategy of hydrocephalus mainly involves the insertion of a ventriculoperitoneal shunt and is inherently related with a complication widely known as shunt over-drainage. Albeit this is a well-recognized complication, the true incidence and severity of this phenomenon remains undefined and most probably underdiagnosed, necessitating a more comprehensive pathophysiologic and therapeutic consideration. The slit ventricle syndrome is intimately related with the entity of shunt over-drainage, although who's the definition of the former is implicated by a lack of universally accepted inclusion criteria. Another point of controversy is related with the absence of widely accepted criteria that would be able to discriminate the existing differentiations between these two entities. This is reflected in the fact that there are many proposed, relevant, treatment protocols. The background for all this data is based on the uncertainty and ambiguity regarding the pathophysiological mechanisms that are implicated. Current efforts are centered on the implementation of precautionary measures, as well as on treatment of both of these entities. Currently, there are enough evidence that support the concept that prevention of siphoning via the use of gravitational valves or antisiphon devices is the most efficacious means contained in our current therapeutic armamentarium. We attempt to present an overview of this complex entity, emphasizing on the hydrodynamics of the cerebrospinal fluid circulation in conditions harboring a ventriculoperitoneal shunt, the effect of the siphoning effect and the role of programmable valves and anti-siphon devices in our effort to eliminate this phenomenon. Based on an extensive literature review and on expert opinion, we concluded that the insertion of an anti-siphon device (gravitational shunt valves) could reliably address the issue of over-drainage, when a patient assumes a vertical position. Besides that, there are ongoing prospective studies centered on the safety and efficacy of adjustable gravitational valves, whose results are of ultimate importance. It is of paramount importance to be recognized that, due to the complexity of the pathophysiology of shunted hydrocephalus, lifelong follow-up of patients with ventriculoperitoneal shunts is necessary.

The Role of Antisiphon Devices in the Prevention of Central Ventricular Catheter Obliteration for Hydrocephalus: A 15-Years Institution's Experience Retrospective Analysis.

Shunt over-drainage in patients harboring a ventriculoperitoneal shunt constitutes one of the most devastating, and difficult to manage, side effects associated with this operation. Siphoning is one of the most important contributing factors that predispose to this complication. Based on the fact that the predisposing pathophysiologic mechanism is considerably multiplicated, amelioration of that adverse condition is considerably difficult to achieve. A lot of evidence suggests that the widespread utilization of gravitational valves or antisiphon devices is of utmost importance, in order to minimize or even avoid the occurrence of such complications. The recent literature data highlight that gravity-related, long-lasting shunt over-drainage consists of a momentous factor that could be considered one of the main culprits of central shunt failure. A lot of efforts have been performed, in order to design effective means that are aimed at annihilating siphoning. Our tenet was the investigation of the usefulness of the incorporation of an extra apparatus in the shunt system, capable of eliminating the impact of the siphoning effect, based on the experience that was gained by their long-term use in our institution. A retrospective analysis was performed, based on the data that were derived from our institution’s database, centered on patients to which an ASD was incorporated into their initial shunt device between 2006 and 2021. A combination of clinical, surgical, radiological findings, along with the relevant demographic characteristics of the patients were collected and analyzed. We attempted to compare the rates of shunt dysfunction, attributed to occlusion of the ventricular catheter, in a group of patients, before and after the incorporation of an anti-siphon device to all of them. A total number of 120 patients who have already been shunted due to hydrocephalus of different etiologies, were managed with the insertion of an ASD. These devices were inserted at different anatomical locations, which were located peripherally to the initially inserted valvular mechanism. The data that were collected from a subpopulation of 17 of these patients were subjected to a separate statistical analysis because they underwent a disproportionately large number of operations (i.e., >10-lifetime shunt revisions). These patients were studied separately as their medical records were complicated. The analysis of our records revealed that the secondary implementation of an ASD resulted in a decrease of the 1-year and 5-year central catheter dysfunction rates in all of our patients when compared with the relevant obstruction rates at the same time points prior to ASD insertion. According to our data, and in concordance with a lot of current literature reports, an ASD may offer a significant reduction in the obstruction rates that is related to the ventricular catheter of the shunt. These data could only be considered preliminary and need to be confirmed with prospective studies. Nevertheless, this study could be considered capable of providing supportive evidence that chronic shunt over-drainage is a crucial factor in the pathophysiology of shunt malfunction. Apart from that, it could provide pilot data that could be reviewed in order to organize further clinical and laboratory studies, aiming toward the assessment of optimal shunt valve systems that, along with ASD, resist siphoning.

Global Rostral Midbrain Syndrome (GRMS) and Corpus callosum infarction in the context of shunt overdrainage

We report 3 cases of Global rostral midbrain syndrome (GRMS) and Corpus Callosum (CC) infarction, in the context of hydrocephalus followed by shunt dysfunction and slit ventricles. Prior shunt implantation had been indicated for adult-onset hydrocephalus secondary to aqueductal stenosis of varying causes. All three patients had been stable for months before developing repeated shunt dysfunctions, ultimately progressing to parkinsonism, Parinaud syndrome, akinetic mutism, pyramidal signs, cognitive impairment, CC infarction and slit ventricles, in the context of CSF overdrainage. Parkinsonism-related symptoms responded to dopa in all cases, but Parinaud syndrome and cognitive impairment persisted. Although GRMS has been described in the context of a transtentorial pressure gradient after shunt blockage, in these three cases with similar clinical presentation, reverse transtentorial pressure gradient and slit ventricles due to shunt overdrainage was the likely cause. The authors discuss the role of CC infarction and provide a detailed analysis after gathering previously described data, to unify information under a recognizable clinical entity and better understand the underlying pathophysiology, treatment options and outcome

Ventriculoatrial Shunting: An Escape Option in Patients with Idiopathic Normal Pressure Hydrocephalus Failing Ventriculoperitoneal Drainage

Ventriculoperitoneal (VP) shunting is widely accepted as the gold-standard treatment for idiopathic normal pressure hydrocephalus (iNPH). However, a restricted group of patients experience only minimal or no improvement after the operation. In such cases, the question whether the diagnosis was incorrect or the shunt is malfunctioning remains unanswered. We retrospectively collected data on a 10-year series of VP-shunted patients with iNPH showing transient or minimal improvement of symptoms within 3weeks from surgery. A full workup (including noninvasive diagnostic, cognitive, and invasive tests) was performed. After ruling out mechanical malfunction, we performed a tap test followed by a Katzman test 2 weeks later. The confirmed persistence of disturbance of cerebrospinal fluid dynamics was treated by shunt revision and, if found working, by its replacement into the atrial cavity. Twenty patients were diagnosed with shunt insufficiency. At surgery, the distal end of the shunt was easily extruded and found working in all cases. It was then repositioned into the right atrium (the first 8 patients of the series also underwent failed contralateral abdominal replacement). Early postoperative clinical improvement was always confirmed. In 1 case, shunt overdrainage was corrected by valve upregulation. According to our experience, inadequate distal end placement of a shunt might be one of the reasons needing investigation in patients with iNPH failing improvement after surgery. In such situations, the conversion to a ventriculoatrial shunt proved to be a low-cost and successful treatment option.

Severity of upper limb discrepancies affect the postural balance in children with obsteric brachial plexus palsy (pilot study)

Ventriculoperitoneal (VP) shunting is widely accepted as the gold-standard treatment for idiopathic normal pressure hydrocephalus (iNPH). However, a restricted group of patients experience only minimal or no improvement after the operation. In such cases, the question whether the diagnosis was incorrect or the shunt is malfunctioning remains unanswered.We retrospectively collected data on a 10-year series of VP-shunted patients with iNPH showing transient or minimal improvement of symptoms within 3 weeks from surgery. A full workup (including noninvasive diagnostic, cognitive, and invasive tests) was performed. After ruling out mechanical malfunction, we performed a tap test followed by a Katzman test 2 weeks later. The confirmed persistence of disturbance of cerebrospinal fluid dynamics was treated by shunt revision and, if found working, by its replacement into the atrial cavity.Twenty patients were diagnosed with shunt insufficiency. At surgery, the distal end of the shunt was easily extruded and found working in all cases. It was then repositioned into the right atrium (the first 8 patients of the series also underwent failed contralateral abdominal replacement). Early postoperative clinical improvement was always confirmed. In 1 case, shunt overdrainage was corrected by valve upregulation.According to our experience, inadequate distal end placement of a shunt might be one of the reasons needing investigation in patients with iNPH failing improvement after surgery. In such situations, the conversion to a ventriculoatrial shunt proved to be a low-cost and successful treatment option.

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.

External cranial expansion as treatment of intracranial hypertension. Technical note.

Intracranial hypertension may be idiopathic or due to multiple etiologies. Some bone dysplasias and chronic shunt overdrainage syndrome may sometimes lead to intracranial hypertension associated with craniocerebral disproportion due to thickening of cranial diploe. The internal cranial expansion procedure has been used for patients with intracranial hypertension, whether or not associated with craniocerebral disproportion. Its purpose is to increase the intracranial volume by drilling down the inner table. This technique enables the craniocerebral disproportion to be improved and intracranial hypertension reduced. In other etiologies of intracranial hypertension with non-thickened diploe, internal cranial expansion may not be enough to resolve the hypertension. For these cases we propose a modification of the technique by expanding the cranial vault outwards; external cranial expansion. We describe this technique as used in a pediatric patient who presented with chronic headache, tonsillar ectopia, and sleep apnea syndrome. This patient also had a multisuture craniosynostosis, a non-thickened diploe, and intracranial hypertension.

Intraventricular Fluid Injection as a Novel Treatment of Subdural Fluid Collection after VP Shunt Overdrainage: A Case Report

Introduction: Subdural fluid collection is one of many complications of ventriculoperitoneal (VP) shunt. Variety of surgical procedures have been applied for the treatment of the post VP shunt subdural fluid collection, but the ideal surgical treatment remains controversial. Case Report: This is a case report of 14 years old boy who had a history of multiple VP shunt revisions for post hemorrhagic hydrocephalus with subdural fluid collections due to cerebrospinal fluid (CSF) overdrainage. Result: The author performed intraventricular fluid injection via shunt valve to expand the brain mantle and drain the subdural fluid through a small craniotomy. This is the first case report using the novel “fluid infusion” technique for the treatment of intractable subdural fluid collection after the VP shunt overdrainage. Conclusion: The technique can bring potentially great impact for the future treatment of symptomatic subdural fluid collection associated with CSF overdrainage after VP shunt.

How to Choose a Shunt for Patients with Normal Pressure Hydrocephalus: A Short Guide to Selecting the Best Shunt Assembly.

Most patients with hydrocephalus are still managed with the implantation of a cerebrospinal fluid (CSF) shunt in which the CSF flow is regulated by a differential-pressure valve (DPV). Our aim in this review is to discuss some basic concepts in fluid mechanics that are frequently ignored but that should be understood by neurosurgeons to enable them to choose the most adequate shunt for each patient. We will present data, some of which is not provided by manufacturers, which may help neurosurgeons in selecting the most appropriate shunt. To do so, we focused on the management of patients with idiopathic “normal-pressure hydrocephalus” (iNPH), as one of the most challenging scenarios, in which the combination of optimal technology, patient characteristics, and knowledge of fluid mechanics can significantly modify the surgical results. For a better understanding of the available hardware and its evolution over time, we will have a second look at the design of the first DPV and the reasons why additional devices were incorporated to control for shunt overdrainage and its related complications. We try to persuade the reader that a clear understanding of the physical concepts of the CSF and shunt dynamics is key to understand the pathophysiology of iNPH and to improve its treatment.

Hydrodynamic comparison of shunt and endoscopic third ventriculostomy in adult hydrocephalus using in vitro models and fluid-structure interaction simulation

ObjectiveThe comparison of the efficiency of shunt placement and endoscopic third ventriculostomy (ETV) in treating of adult hydrocephalus patients with various intensities and different obstruction intensities in the aqueduct of Sylvius (AS). MethodsIn vitro models with separated ventricles were simulated and implemented for modeling shunt and ETV surgeries in one healthy subject and hydrocephalus patients with various intensities, as well as three different obstruction intensities in AS and under two cerebrospinal fluid (CSF) dynamic conditions. The fluid-structure interaction simulation was also carried out to validate in vitro results. ResultsThe efficiency of both methods in reducing the maximum CSF pressure in the subarachnoid space (MCPS) decreased by an increase in the patient's intensities. Contrary to shunting, the efficiency of ETV in reducing MCPS demonstrated a decline (8.3–16.4%) by an increase in obstruction levels in AS. Based on the findings, shunt efficiency in decreasing MCPS in patients with low intensity was more remarkable compared to ETV. However, ETV was more efficient than shunt in the patient with intracranial hypertension. Further, shunt placement and ETV led to a significant reduction in the amplitude of CSF pressure in the SAS (ACPS) in patients with sneezing, coughing, Valsalva maneuver, and exercising effects in contrast to other patients. Moreover, ACPS reduction was not related to the intensity of the disease in both treatment methods. In contrast to shunt, an increase in the obstruction level in AS led to a reduction in ACPS in ETV in both CSF dynamic conditions. ConclusionsThe noises from irregular disorders increased the discharging of CSF after shunt placement, and activities such as sneezing, coughing, Valsalva maneuvers, and exercising increased the risk of shunt overdrainage by 10.4~47.8%, especially in the patient with intracranial hypertension. Based on the proposed in vitro ETV and shunt models, an increase of head compliance was higher in ETV compared to the shunt. Eventually, an increase in the obstruction level of AS after ETV led to a decline in head compliance in contrast to shunt.

Considerations in the Use of Gravitational Valves in the Management of Hydrocephalus. Some Lessons Learned with the Dual-Switch Valve.

In the past decade, there has been a clear trend towards better outcomes in patients with hydrocephalus, especially those with normal pressure hydrocephalus (NPH). This is partly due to the availability of more sophisticated hardware and a better understanding of implants. However, there is little evidence to show the superiority of a specific type of valve over another. The most commonly reported consequence of hydrodynamic mismatch is shunt over-drainage. Simple differential pressure valves, with a fixed opening pressure or even adjustable valves, lead to non-physiologic intraventricular pressure (IVP) as soon as the patient moves into an upright posture. These valves fail to maintain IVP within physiological limits due to the changes in hydrostatic pressure in the drainage system. To solve this problem more complex third-generation hydrostatic valves have been designed. These gravitational devices aim to reduce flow through a shunt system when the patient is upright but there are important technical differences between them. Here we review the main characteristics of the Miethke® Dual-Switch valve, which includes two valve chambers arranged in parallel: a low-opening pressure valve, designed for working in the supine position, and a second high-opening pressure valve, which starts working when the patient assumes the upright position. This paper specifies the main advantages and drawbacks of this device and provide a series of recommendations for its use. The discussion of this specific gravitational valve allows us to emphasize the importance of using gravitational control in implanted shunts and some the caveats neurosurgeons should take into consideration when using gravitational devices in patients with hydrocephalus. The correct function of any gravitational device depends on adequate device implantation along the vertical body axis. Misalignment from the vertical axis equal to or more than 45° might eliminate the beneficial effect of these devices.

Chest Implantation of Adjustable Gravitational Valves: An Easy, Safe, and Stable Alternative to Control Symptomatic Overdrainage in Shunted Children

Shunt overdrainage is a potential complication in pediatric hydrocephalus. The addition of adjustable gravitational units to previous shunt systems has been proposed as effective management for this problem. These devices have been traditionally implanted over the occipital bone. We propose chest implantation as an easier, safer, and more stable alternative in the pediatric population, especially in those cases with parieto-occipital shunts. This study comprises a retrospective analysis from a unicentric case series of pediatric patients affected by overdrainage and managed with adjustable gravitational valves implanted in the chest. The device implantation technique is described in detail and takes no more than 15 minutes. Thirty-seven patients met the criteria. The mean age of implantation was 9.62 years. The mean follow-up in the series was 38 months. The mean number of pressure adjustments was 2.48. The mean "deviation angle" of the device to the longitudinal body axis was 5.8°. The complications per year of shunt were <0.02 with no disconnection of the catheters in any case during follow-up. In our experience, chest implantation for adjustable gravitational devices was a suitable shunt modification in pediatric patients suffering from overdrainage.

In Reply to the Letter to the Editor Regarding “Reversible Severe Brainstem Herniation and Obstructive Hydrocephalus from Cystoperitoneal Shunt Overdrainage”

Suprasellar arachnoid cysts are a rare but important pediatric neurosurgical pathology with unknown ideal management. They have been previously managed with techniques including open craniotomy with microsurgical fenestration, cystoperitoneal shunting, endoscopic ventriculocystostomy, and endoscopic ventriculocystocisternostomy (VCC), without a consistent consensus on the best surgical approach. We present an overview of the literature on surgical management of suprasellar arachnoid cysts.A literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted for all articles evaluating treatment modalities for suprasellar arachnoid cysts, using PubMed, OVID, and Web of Science.Twenty-five articles on management of suprasellar arachnoid cysts in children were identified. Few published studies exist that examine different types of surgical management across a single institution. The majority of studies reported best clinical outcomes in patients treated with endoscopic approaches when compared with microsurgical fenestration or cystoperitoneal shunting, reporting lower rates of infection, shunt dependence, and need for revision in addition to better resolution of clinical symptoms. Furthermore, most studies argue that VCC is superior to ventriculocystostomy, offering better long-term improvement of clinical symptoms and lower rates of failure.This study examines the current literature on suprasellar arachnoid cyst surgical management to conclude that an endoscopic approach in comparison with other approaches has the best outcomes. Of the endoscopic options available, VCC provides patients with the best long-term resolution of symptoms and the lowest need for revision. These findings should be further investigated with larger multicenter studies to further compare different surgical techniques and outcomes.

A comparison between flow-regulated and adjustable valves used in hydrocephalus during infancy.

Ventriculoperitoneal shunt insertion during the neonatal period and early infancy is associated with a high rate of shunt failure when compared to the adult population. Furthermore, the function of flow-regulated valves and differential pressure valves may be different in neonatal hydrocephalus. A retrospective case series of all primary shunt procedures carried out during or immediately following the neonatal period, from August 2011 to February 2018 at Sheffield Children's Hospital. The total sample size was 55. This included 34 patients with adjustable valves (Miethke ProGav) and 21 with flow-regulated valves (Orbis-Sigma); however, only 53 had adequate follow-up. The overall 1year shunt survival was 34% (18/53), and there was no significant difference depending on which shunt valve was implanted. The primary shunt infection rate was 11% (6/53) with S. aureus being the most common causative organism. During the first year of life, clinical signs of shunt overdrainage were seen more frequently in patients with adjustable valves than in those with flow-regulated valves (59% [19/32] versus 24% [5/21], p= 0.02). Furthermore, 2 patients in the adjustable valve group developed sagittal craniosynostosis secondary to shunt overdrainage. Shunt failure is high when inserted during or immediately following the neonatal period. Overdrainage may be less common in patients with flow-regulated valves. However, if overdrainage is observed, adjusting the setting of a differential pressure valve can effectively treat the overdrainage without the need for invasive shunt revision surgery.

Neuroendoscopic treatment of arachnoid cysts in the paediatric population. Series results for 20 patients

IntroductionNeuroendoscopy has become an effective and safe treatment for arachnoid cysts in the paediatric population. We review the paediatric patients with arachnoid cysts treated by neuroendoscopy in our hospital and analyse the results. Material and methodsA retrospective analysis of 20 patients operated on from 2005 to 2018. The variables assessed are: gender, age, clinical presentation, cyst site, presence of hydrocephalus and/or extra-axial collections, endoscopic procedures and complications. Procedure success is defined as an improvement in symptoms and reduction in cyst size until end of follow-up. ResultsOur series comprised 13 males and 7 females (mean age: 64.6 months, range: 4–172 months). The most frequent site was suprasellar-prepontine (7), followed by intraventricular (6), quadrigeminal (3), interhemispheric (2) and Sylvian (2).A total of 70% (14/20) of patients had hydrocephalus at diagnosis, which increased to 85% in suprasellar-prepontine cysts and 100% in quadrigeminal cysts. Only 4/14 patients with required a ventriculoperitoneal shunt (median age at diagnosis: 12.5 months). Of these 4 patients, 3 developed severe shunt overdrainage.The procedure was successful in 60% (12/20) of the patients in the series. Success by location was 57% (4/7) in suprasellar cysts, 33% (1/3) in quadrigeminal cysts, 66% (4/6) in intraventricular cysts, 100% (2/2) in interhemispheric cysts and 50% (1/2) in Sylvian cysts. Treatment thus failed in 8 cases, with a mean time to failure of 12.12 months (range: 0–45 months). A new neuroendoscopic procedure was performed in 4 of these 8 cases (success in 2/4), a ventriculoperitoneal shunt was placed in 2 cases, a cystoperitoneal shunt was placed in 1 case and the remaining case was managed conservatively. Mean follow-up time was 52.45 months (range: 3–129 months). ConclusionsNeuroendoscopy is an effective and safe treatment for arachnoid cysts in paediatric patients that also enables managing associated hydrocephalus in most cases. The choice of neuroendoscopic procedure and success rate depend on cyst location. Younger patients have been found to have a higher shunt dependency rate. In these cases, measures to prevent shunt overdrainage are recommended.