Positional shunt assist for slit ventricle syndrome.

PURPOSE: Hydrocephalus is one of the most common pathologies in pediatric neurosurgery. One of the causes of recurring events of headaches among shunted children is "slit ventricle syndrome" (SVS). Several potential treatments have been proposed, yet SVS often represents a treatment challenge. The goal of the current series is to present our experience with adding a positional shunt-assist (SA) (Miethke, Aesculap) for the treatment of SVS. METHODS: Clinical data was retrospectively collected from all consecutive children with SVS that were treated with SA (Miethke, Aesculap) at our center. Surgical and clinical outcomes as expressed by hospital visits, or need for additional surgery, were evaluated. RESULTS: Nine cases were included. Hydrocephalus etiology included IVH (6), postinfectious (1), and congenital syndromes (2). Average age at first shunt was 4 months. Primary shunt type was differential-pressure-valve in all. Average age at SVS onset was 4 years. Average age at SA placement was 5.5 years. There were no perioperative complications besides a single stich abscess. A 6-month follow-up period after SA was compared to a 6-month period prior to the SA: average hospital visits decreased from 2.4 to 0.6 per patient (p < 0.0002). 4/9 patients needed an LP or shunt revision before the SA surgery, while no procedure was indicated during the immediate 6-month follow-up. At the last follow-up, there was a significant reduction in the rate of ER visits compared to prior to surgery; however, the number of neurosurgical procedures did not significantly differ. CONCLUSION: Using a SA for SVS was associated with a short-term improvement of symptoms in the majority of cases, reduction in hospital visits, and reduced need for SVS-related procedures.

Subtemporal Decompression in Resistant Slit Ventricle Syndrome in Children: An Observational Study and Survival Analysis.

INTRODUCTION: Slit ventricle syndrome (SVS) remains a challenging problem in the early-shunted paediatric population. Various surgical and non-surgical treatments have been devised for this condition. However, there is currently no gold standard for its optimal management. Among various treatment modalities, subtemporal decompression (STD) is often performed as a last resort. We present our experience of STD in paediatric patients with SVS in whom initial treatment with programmable valves and anti-syphon device were not successful. METHODS: This is a single-centre retrospective observational study and survival analysis. Patients who underwent STD for SVS were included. Pre- and post-operative imaging data and clinical outcomes were collected. RESULTS: There were 20 patients (12 M, 8 F) with a mean age of 9 years (SD: 4) at first STD. 90% (n = 18) of patients had multiple shunt revisions pre-STD. At first STD, 70% (n = 14) and 30% (n = 6) of patients had unilateral or bilateral STD, respectively. STD led to a reduction in the frequency of shunt revisions in 60% (n = 12) of patients. The median time required before further STD, shunt surgery, or cranial vault surgery was 14 months. The median time before a further STD was required (either revision or contralateral side) was 89 months. At a median follow-up of 66.5 months (range: 1-159), 65% (n = 13) of patients had improvement in symptoms. CONCLUSIONS: A large proportion of patients with persistent SVS symptoms, refractory to multiple shunt revisions, benefitted from STD in combination with shunt optimization. It was also safe and well-tolerated. Therefore, in patients who have multiple failed shunts, STD may reduce the morbidity associated with further shunt revisions and can significantly improve symptomatology.

Slit Ventricle Syndrome.

Slit ventricle syndrome (SVS) is a complication after ventriculoperitoneal shunt (VPS) or cystoperitoneal shunt(CPS), mostly due to excessive drainage of cerebrospinal. The disease is most often seen in children and has a complex pathogenesis. Clinical manifestations are mainly intermittent headache, slow refilling of the shunt reservoir, and slit-like ventricles on imaging. Surgery is the main treatment. We present a 22-year-old female patient with a previous 14-year history of CPS. The patient recently presented with typical symptoms but her ventricular morphology was normal. We performed VPS after diagnosis of SVS. After the surgery, the patient's symptoms improved and her condition was stable.

Noninvasive intracranial pressure monitoring throughout brain compliance guiding a ventriculoperitoneal shunt replacement in hydrocephalus-case report.

INTRODUCTION: Ventriculoperitoneal (VP) shunt is the primary therapy for hydrocephalus in children; however, this technique is amenable to malfunctions, which could be detected through an assessment of clinical signs and imaging results. Furthermore, early detection can prevent patient deterioration and guide clinical and surgical treatment. CASE PRESENTATION: A 5-year-old female with a premedical history of neonatal IVH, secondary hydrocephalus, multiple VP shunts revisions, and slit ventricle syndrome was evaluated using a noninvasive intracranial pressure monitor device at the early stages of the clinical symptoms, evidencing increased intracranial pressure and poor brain compliance. Serial MRI images demonstrated a slight ventricular enlargement, leading to the use of a gravitational VP shunt, promoting progressive improvement. On the follow-up visits, we used the noninvasive ICP monitoring device to guide the shunt adjustments until symptom resolution. Furthermore, the patient has been asymptomatic for the past 3 years without requiring new shunt revisions. DISCUSSION: Slit ventricle syndrome and VP shunt dysfunctions are challenging diagnoses for the neurosurgeon. The noninvasive intracranial monitoring has allowed a closer follow-up assisting early assessment of brain compliance changes related to a patient's symptomatology. Furthermore, this technique has high sensitivity and specificity in detecting alterations in the intracranial pressure, serving as a guide for the adjustments of programmable VP shunts, which may improve the patient's quality of life. CONCLUSION: Noninvasive ICP monitoring may lead to a less invasive assessment of patients with slit ventricle syndrome and could be used as a guide for adjustments of programmable shunts.

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.

Visual acuity loss and sixth nerve palsy as the only manifestations of slit ventricle syndrome.

The case is presented of a girl diagnosed with obstructive hydrocephalus due to pilomyxoid astrocytoma, which required a ventriculoperitoneal shunt (VPS) at the age of 5 years and 10 months. Two months later, magnetic resonance imaging of the brain did not show ventriculomegaly or other signs of increased intracranial pressure. At the age of 6 years and 2 months, a rapid onset of bilateral visual acuity loss developed and she was diagnosed with slit ventricle syndrome. Despite valve revisions of the VPS, she developed an abrupt decline of visual acuity to hand motion at 10 cm. Fundus examination revealed bilateral optic atrophy. She did not report any other systemic symptoms suggesting increased intracranial pressure, such as headache, nausea, vomiting, lethargy, irritability, or altered levels of consciousness.

Pérdida de agudeza visual y parálisis de VI nervio craneal como únicas manifestaciones de un síndrome de colapso ventricular / Visual acuity loss and sixth nerve palsy as the only manifestations of slit ventricle syndrome

Se describe una niña con hidrocefalia obstructiva por un astrocitoma pilomixoide, que requirió implantar una derivación ventrículo-peritoneal (DVP) a los 5 años y 10 meses de edad. Dos meses después, la resonancia magnética cerebral no mostró ventriculomegalia ni otros signos de aumento de la presión intracraneal. A la edad de 6 años y 2 meses desarrolló una rápida disminución de la agudeza visual bilateral siendo diagnosticada de síndrome de colapso ventricular. A pesar de las revisiones valvulares de la DVP, se produjo una disminución abrupta de la agudeza visual a movimientos de mano a 10cm. El examen del fondo de ojo reveló atrofia óptica bilateral. No refirió otros síntomas sistémicos que sugirieran un aumento de la presión intracraneal, como dolor de cabeza, náuseas, vómitos, letargia, irritabilidad o niveles alterados de conciencia.

The case is presented of a girl diagnosed with obstructive hydrocephalus due to pilomyxoid astrocytoma, which required a ventriculoperitoneal shunt (VPS) at the age of 5 years and 10 months. Two months later, magnetic resonance imaging of the brain did not show ventriculomegaly or other signs of increased intracranial pressure. At the age of 6 years and 2 months, a rapid onset of bilateral visual acuity loss developed and she was diagnosed with slit ventricle syndrome. Despite valve revisions of the VPS, she developed an abrupt decline of visual acuity to hand motion at 10cm. Fundus examination revealed bilateral optic atrophy. She did not report any other systemic symptoms suggesting increased intracranial pressure, such as headache, nausea, vomiting, lethargy, irritability, or altered levels of consciousness.

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.

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.

Novel Endoscopic Technique for Inserting a Sheath into a Slit Ventricle: The Water-Slide Technique.

BACKGROUND: The efficacy and safety of endoscopic procedures for slit ventricle syndrome (SVS) have been presented in recent studies. However, inserting a sheath into a target ventricle is essential in the beginning of endoscopic procedures for SVS, and this maneuver is challenging owing to the quite narrow ventricular space. We report a novel flexible endoscopic technique, the water-slide technique, that can effectively guide a sheath into a slit ventricle without the use of other adjunctive devices, such as a neuronavigation system and an ultrasound machine. METHODS: Ten endoscopic procedures using the water-slide technique were performed in 9 patients with SVS. All patients had undergone ventriculoperitoneal shunt placement. Using the technique, the sheath was first placed on the flexible endoscope. The endoscope was then inserted into the lateral ventricle along the tract around the pre-existing ventricular catheter with irrigation of artificial cerebrospinal fluid via the working channel of the endoscope. After the endoscope reached the ventricle, the sheath was inserted into the ventricle along the endoscope. The endoscope was then used as a stylet. The endoscopic procedure was performed afterward. Continuous irrigation of artificial cerebrospinal fluid via the working channel is important when using this technique. RESULTS: In all cases, the sheath was successfully introduced to the slit ventricle without the use of adjunctive devices. There were no postoperative complications correlated with the maneuver. CONCLUSIONS: This novel endoscopic technique is effective and safe for inserting a sheath into a target ventricle in the management of SVS.

Cranial expansion and aqueductoplasty for combined isolated fourth ventricle and slit-ventricle syndrome: a surgical alternative.

INTRODUCTION: An isolated fourth ventricle (IFV) is a rare entity observed in shunted patients and its treatment is still uncertain. Endoscopic aqueductoplasty has shown good results for restoring CSF flux between the third and fourth ventricles. However, it needs some grade of ventricular dilation to be performed. Some patients affected by IFV show slit-ventricle morphology in CT/MRI. Usually, the rise of opening pressure or the shunt externalization gets enough ventricular dilation. However, the lack of intracranial compliance in some patients makes these options unsuitable and high-ICP symptoms are developed without ventricular dilation. METHODS: We present a two cases series affected by IFV with no ventricular dilation in radiological exams. ICP sensors were implanted, observing high-ICP and establishing the diagnosis of craniocerebral disproportion. A two-stage surgical plan based on a dynamic cranial expansion followed by a supratentorial endoscopic aqueductoplasty was performed. A physical and mathematical model explaining our approach was also provided. RESULTS: Chess-table cranial expansion technique was performed in both patients. Six/seven days after the first surgery, respectively, ventricular dilation was observed in CT. Endoscopic precoronal aqueductoplasty was then performed. No postoperative complications were described. IFV symptoms improved in both patients. Eighteen and 12 months after the two-stage surgical plan, the patients remain symptom-free and void of flow is still observed between the third and the fourth ventricles in MRI. CONCLUSION: The two-stage approach was a suitable option for the treatment of these complex patients affected by both craniocerebral disproportion and isolated fourth ventricle.

Predictors of fast and ultrafast shunt failure in pediatric hydrocephalus: a Hydrocephalus Clinical Research Network study.

OBJECTIVE: The primary objective of this study was to use the prospective Hydrocephalus Clinical Research Network (HCRN) registry to determine clinical predictors of fast time to shunt failure (≤ 30 days from last revision) and ultrafast time to failure (≤ 7 days from last revision). METHODS: Revisions (including those due to infection) to permanent shunt placements that occurred between April 2008 and November 2017 for patients whose entire shunt experience was recorded in the registry were analyzed. All registry data provided at the time of initial shunt placement and subsequent revision were reviewed. Key variables analyzed included etiology of hydrocephalus, age at time of initial shunt placement, presence of slit ventricles on imaging at revision, whether the ventricles were enlarged at the time of revision, and presence of prior fast failure events. Univariable and multivariable analyses were performed to find key predictors of fast and ultrafast failure events. RESULTS: A cohort of 1030 patients with initial shunt insertions experienced a total of 1995 revisions. Of the 1978 revision events with complete records, 1216 (61.5%) shunts remained functional for more than 1 year, and 762 (38.5%) failed within 1 year of the procedure date. Of those that failed within 1 year, 423 (55.5%) failed slowly (31-365 days) and 339 (44.5%) failed fast (≤ 30 days). Of the fast failures, 131 (38.6%) were ultrafast (≤ 7 days). In the multivariable analysis specified a priori, etiology of hydrocephalus (p = 0.005) and previous failure history (p = 0.011) were independently associated with fast failure. Age at time of procedure (p = 0.042) and etiology of hydrocephalus (p = 0.004) were independently associated with ultrafast failure. These relationships in both a priori models were supported by the data-driven multivariable models as well. CONCLUSIONS: Neither the presence of slit ventricle syndrome nor ventricular enlargement at the time of shunt failure appears to be a significant predictor of repeated, rapid shunt revisions. Age at the time of procedure, etiology of hydrocephalus, and the history of previous failure events seem to be important predictors of fast and ultrafast shunt failure. Further work is required to understand the mechanisms of these risk factors as well as mitigation strategies.

Aesthetic Cranial Vault Expansion in a Child With Slit Ventricle Syndrome and Eumorphic Face.

Ventricular shunting procedures represent the classical surgical treatment for hydrocephalus. Slit ventricle syndrome (SVS) with craniocerebral disproportion (CCD) and secondary craniosynostosis (SCS) is a well-known but uncommon complication following cerebrospinal fluid (CSF) shunting in children. Its general management includes shunt upgrade or revision, placement of anti-siphon devices, lumbo-peritoneal shunting, and endoscopic third ventriculostomy. Cranial expansion is generally considered a major procedure and is indicated when less invasive treatments fail. In these cases, SVS and associated SCS have been usually managed through anterior cranial vault expansion. This procedure aims to decrease the risk of further shunt revisions and to improve neurologic symptoms, but it takes the disadvantage of considerable iatrogenic alterations of the facial proportions. The authors report a case of a 6-year old boy with SVS and SCS, who maintained eumorphic face and was treated by an innovative post-coronal vault expansion ensuring a wide volume increase while avoiding any change of facial conformation.

Slit Ventricle as a Neurosurgical Emergency: Case Report and Review of Literature.

BACKGROUND: Symptomatic slit ventricle is one of the most challenging complications of shunt surgery in children. Clinical signs and symptoms may appear with a wide range of intracranial pressure (ICP) values. We report the case of a 10-year-old girl, who did not present the classic clinical features of extremely elevated ICP, which was proven by multiple invasive ICP recordings, performed during shunt revisions. CASE DESCRIPTION: At the age of 6 months, the patient presented squeal for many hours, accompanied with sunset eyes, bulging anterior fontanel, and dilated ventricles of all 4 ventricles on computed tomography scan. Acute ventriculoperitoneal shunt insertion was performed with adjustable valve. During the following 9 years, she was regularly seen and medically treated for intermittent headache, with nausea and vomiting. From 9 years of age, she was hospitalized for severe (10/10 on the visual analog scale), unbearable headache, agitation, and screaming on multiple occasions. Altogether, we had to revise the shunt system 5 times throughout 1 year. Radiologic imaging always showed narrow ventricles. Ophthalmologic examination of the fundus never revealed signs of raised ICP. Perioperative monitoring of the ICP with intraparenchymal sensor showed unexpected high values of 40-45 mm Hg. However, repetitive shunt revisions were successful only temporarily because the symptoms always returned. Only bilateral shunting of the ventricular system was able to eliminate the symptoms permanently. CONCLUSIONS: Images of slit ventricle can be associated either with low or extremely high ICP needing urgent surgical consideration, including ICP monitoring. Bilateral shunt insertion can be effective treatment for slit ventricle syndrome.

Slit Ventricle Syndrome Leads to 10-Year History of Repetitive Transient Central Herniation Masquerading as Seizures: Hydrocephalus Case Report.

BACKGROUND: Slit-ventricle syndrome (SVS) is a recognized complication of ventricular shunt malfunction, resulting in cyclical symptoms without ventricular dilatation. We present a case of SVS with transient, repetitive, and progressive signs of brainstem herniation evidenced by pupillary dilatation, posturing, and unresponsiveness, with diffuse voltage attenuation on electroencephalogram (EEG). CASE DESCRIPTION: A 32-year-old female presented with a history of hydrocephalus and ventriculoperitoneal shunt placement at 9 months of age. She began experiencing significant headaches in college, later accompanied by stereotypical 5- to 25-minute episodes of unresponsiveness, posturing and pupillary dilatation, and failing anticonvulsant therapy. No neurosurgical evaluation was sought because of small ventricles on brain imaging. Episodes became progressively more frequent over a 10-year period, eventually occurring daily. On presentation, 5 clinical events were captured on EEG over 12 hours of monitoring. With each episode, she became unresponsive and hypertensive, with fixed, dilated pupils and flexor posturing. Between events, she was awake and alert, without confusion or postictal state. She had papilledema and limited extraocular movements, with normal pupils and vital signs. Computed tomography scanning showed small ventricles. A shunt tap revealed no flow. With each episode onset, an EEG revealed an abrupt background rhythm slowing to 2-3 Hz delta range without epileptiform discharges. Between events, EEGs displayed normal waveform activity. Emergent ventriculoperitoneal shunt revision resulted in no further episodes in a 4-year follow-up period. CONCLUSIONS: SVS can lead to severe intermittent brainstem herniation syndrome in the setting of shunt malfunction. Seizure diagnosis should be reserved for cases with proven functional shunt and EEG confirmation of epileptiform activity.

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.

Shunt overdrainage syndrome: review of the literature.

Shunt overdrainage in patients with hydrocephalus still represents a challenge for neurosurgeons, in part due to the lack of agreement or uniformity concerning the entity. Important problems exist relating to the real incidence of the entity, its definition, classification, and the pathophysiological theories behind the various treatment strategies proposed. Recent reports have suggested that the evidence about overdrainage and its consequences is not so robust as presumed. Consequently, the topic requires more detailed examination. In this review, we comment on all the main facets related with shunt overdrainage.

Shunt-dependent hydrocephalus: management style among members of the American Society of Pediatric Neurosurgeons.

OBJECTIVE The authors conducted a survey to evaluate differences in the understanding and management of shunt-dependent hydrocephalus among members of the American Society of Pediatric Neurosurgeons (ASPN). METHODS Surveys were sent to all 204 active ASPN members in September 2014. One hundred thirty responses were received, representing a 64% response rate. Respondents were asked 13 multiple-choice and free-response questions regarding 4 fundamental problems encountered in shunted-hydrocephalus management: shunt malfunction, chronic cerebrospinal fluid (CSF) overdrainage, chronic headaches, and slit ventricle syndrome (SVS). RESULTS Respondents agreed that shunt malfunction occurs most often as the result of ventricular catheter obstruction. Despite contrary evidence in the literature, most respondents (66%) also believed that choroid plexus is the tissue most often found in obstructed proximal catheters. However, free-text responses revealed that the respondents' understanding of the underlying pathophysiology of shunt obstruction was highly variable and included growth, migration, or adherence of choroid plexus, CSF debris, catheter position, inflammatory processes, and CSF overdrainage. Most respondents considered chronic CSF overdrainage to be a rare complication of shunting in their practice and reported wide variation in treatment protocols. Moreover, despite a lack of evidence in the literature, most respondents attributed chronic headaches in shunt patients to medical reasons (for example, migraines, tension). Accordingly, most respondents managed headaches with reassurance and/or referral to pain clinics. Lastly, there were variable opinions on the etiology of slit ventricle syndrome (SVS), which included early shunting, chronic overdrainage, and/or loss of brain compliance. Beyond shunt revision, respondents reported divergent SVS treatment preferences. CONCLUSIONS The survey shows that there is wide variability in the understanding and management of shunt-dependent hydrocephalus and its complications. Such discrepancies appear to be derived partly from inconsistent familiarity with existing literature but especially from a paucity of high-quality publications.