Midline developmental abnormalities of the posterior fossa: correlation of classification with outcome

The Management of Hydrocephalus in Midline Posterior Fossa Cystic Collections: Surgical Outcome From a Retrospective Single-Center Case Series of 54 Consecutive Pediatric Patients

BACKGROUND

Hydrocephalus frequently occurs with midline posterior fossa cystic collections. The classification of this heterogeneous group of developmental anomalies, including Dandy-Walker malformation, persisting Blake's pouch, retrocerebellar arachnoid cysts, and mega cisterna magna, is subject of debate. The absence of diagnostic criteria is confusing regarding the ideal management of PFCC-related hydrocephalus.

OBJECTIVE

To decipher the surgical strategy for the treatment of children with PFCC-related hydrocephalus through a retrospective analysis of the surgical outcome driven by their clinical and radiological presentation.

METHODS

This study enrolled patients operated of symptomatic PFCC-related hydrocephalus. Clinical and MRI features were examined, as well as the surgical outcome. Unbiased subgroup classification of the patients was performed with multiple component analysis as a function of imaging characteristics and hierarchical clustering on principal component. Outcome was assessed with binomial logistic regression and Kaplan-Meier analysis.

RESULTS

Fifty-four patients were included between 2007 and 2021. Multiple component analysis suggested that cerebellar and vermian hypoplasia, vermian rotation, basal-tentorial angle, and fastigial angle were strongly correlated. Hierarchical clustering and the distribution of the patients in the bidimensional plot showed the clear segregation of 3 major clusters, which correlated with the radiological diagnosis ( P < .01). Binomial logistic regression and survival analysis showed that endoscopic third ventriculostomy was an effective treatment for patients with persisting Blake's pouch, while failing to control hydrocephalus in most of patients with Dandy-Walker malformation.

CONCLUSION

Preoperative MRI in patients with PFCC-related hydrocephalus is essential to better define the diagnosis. The choice of treatment strategy notably relies on correct radiological diagnosis.

Craniomegaly in Neonate and Infants Requiring Neurosurgical Intervention: An Experience at Tertiary Care Center

Background The identification of neurosurgical causes of craniomegaly and early institution of therapy requires for better clinical and functional outcomes.

Aims and Objectives The aim of this study was to evaluate the neurosurgical causes, managements, and outcomes of craniomegaly in neonate and infants.

Materials and Methods The cases with a history of head enlargement from neonatal period were included in this study. Their causes, managements, and outcomes were recorded retrospectively during the period of January 2010 to February 2013, in neurosurgery department at SGPGIMS Lucknow, and June 2018 to June 2020, at UPUMS, Saifai, Etawah, UP, India.

Results Out of 41 cases, there were 30 (73.14%) cases of hydrocephalus, 4 (9.76%) Dandy-Walker malformation, 2 (4.88%) subdural collection, 2 (4.88%) arachnoid cyst, 1 (2.44%) craniosynostosis, and 2 (4.88%) with tubercular meningitis. The age range of our cases was 18 to 178 days and the mean age was 102.54 ± 50.73. Preoperative head circumference range was 39 to 62 cm (mean: 55.27 ± 6.58cm). Majority of the cases (n = 32, 78.05%) were managed with ventriculoperitoneal shunt surgeries. Out of 41 cases, 33(80.49%) had improved outcomes, 7 (17.07%) stabilized, and mortality occurred in 1 (2.44%) case. Postoperatively, there was improvement in the head circumference (range: 39–60 cm and mean: 46.15 ± 5.83 cm) on 6 to 24 months (mean: 17.85 ± 5.18 months) of follow-up.

Conclusion Hydrocephalus was the commonest neurosurgical cause of head enlargement in neonate and infants. Shunt surgery was the most common form of management of these cases. Early detection, institution of therapy, and periodic follow-up program for diagnosing and treating complications were the key to successful outcomes in these patients.

Predicting outcomes in Dandy-Walker malformation: a retrospective cohort study

OBJECTIVE

Dandy-Walker malformation (DWM) is a disorder that most neurologists and neurosurgeons will manage at some point during their careers. It is characterized by partial or complete dysgenesis of the cerebellar vermis. Outcomes are highly variable and range from functionally normal to severely disabled. Predicting these outcomes has classically been focused on the radiological findings that constitute DWM. Other anomalies that can be commonly found in these patients are potentially more indicative of outcome than the tenet markers of DWM. Furthermore, hydrocephalus is an ever-present danger in these patients, many of whom will be admitted to the hospital due to this condition. This study aims to identify these items as potential predictors of outcome.

METHODS

All referrals from antenatal anatomy scans between 1992 and 2013 that were suspicious for DWM were reviewed. Neurosurgery archives were reviewed for outpatient letters and other correspondence. The number of DWM diagnoses was quantified. Outcomes were judged based on patient status, ranging from death to attending normal school. The presence of any other anomalies was quantified and measured against patient outcomes.

RESULTS

Cyst size and the presence of another CNS anomaly were shown to portend worse outcomes. Non-CNS anomalies and hydrocephalus were not predictive of worse outcomes. Furthermore, of all the treatments assessed, ventriculoperitoneal shunts were shown to be the most effective in this data set.

CONCLUSIONS

Results from this study suggest a pivot in how prognoses in DWM should be established and how parents should be counseled, along with a view of hydrocephalus and its treatment that challenges the current literature.

Developmental Retrocerebellar Cysts: A New Classification for Neuroendoscopic Management and Systematic Review

OBJECTIVE

Posterior fossa cystic malformations are diversely classified with considerable overlap without therapeutic relevance. These cysts posterior to the cerebellum, presenting in children younger than 5 years, are labeled developmental retrocerebellar cysts (DRCCs) under a new classification in relation to neuroendoscopy.

METHODS

DRCC was categorized as type 0 for asymptomatic enlarged cistern magna and was not treated. Among symptomatic cases, cysts with a compressed fourth ventricle were labeled type 1, whereas cysts in continuity with the fourth ventricle were termed type 2. They were further categorized as subtype B if hydrocephalus was greater relative to the cyst, or otherwise as subtype A. The literature was reviewed according to PRISMA guidelines.

RESULTS

There were 13 children aged 3-48 months. Type 1A DRCC was noted in 5 patients, with onset before 6 months, 4 of whom (80%) had intracranial hypertension. All underwent suboccipital endoscopic deroofing and cisternostomy (SEDC), a new technique. Type 1B DRCC was seen in 2 patients, with onset at 8-9 months, who underwent endoscopic third ventriculostomy (ETV) + endoscopic ventriculocystostomy (EVC). Type 2A DRCC was observed in 4 patients, with onset at 5-47 months, who underwent SEDC. Type 2B DRCC was noted in 2 patients, with onset 6-8 months, who underwent ETV. With a mean follow-up of 32 months, all showed clinicoradiologic improvement. The application of our classification to other studies showed ETV/EVC to be successful in only 67% of type 1A DRCC and 72% of type 2A DRCC, compared with 100% efficacy of SEDC in our series.

CONCLUSIONS

This is probably the first ever endoscopic classification of pediatric posterior fossa cyts, elucidating pathophysiology, presentation, and treatment. Patients with type 1 DRCC present early because of extraneous compression. Among patients with type 2 DRCC, posterior fossa compliance determines the degree of hydrocephalus. The newly described SEDC seems more appropriate for types 1A and 2A DRCC. ETV is adequate in type 2B DRCC and effective with EVC in type 1B.

Current state and future development of intracranial neuroendoscopic surgery

Since the introduction of the modern, smaller endoscopes in the 1960s, neuroendoscopy has become an expanding field of neurosurgery. Neuroendoscopy reflects the tendency of modern neurosurgery to aim towards minimalism; that is, access and visualization through the narrowest practical corridor and maximum effective action at the target point with minimal disruption of normal tissue. Transventricular neuroendoscopy allows the treatment of several pathologies inside the ventricular system, such as obstructive hydrocephalus and intra-/paraventricular tumors or cysts, often avoiding the implantation of extracranial shunts or more invasive craniotomic approaches. Endoscopic endonasal transphenoidal surgery allows the treatment of pathologies of the sellar and parasellar region, with the advantage of a wider vision of the surgical field, less traumatism of the nasal structures, greater facility in the treatment of possible recurrences and reduced complications. However, an endoscope may be used to assist microsurgery in virtually any kind of neurosurgical procedures (endoscope-assisted microsurgery), particularly in aneurysm and tumor surgery. Basic principles of optical imaging and the physics of optic fibers are discussed, focusing on the neuroendoscope. The three main chapters of neuroendoscopy (transventricular, endonasal transphenoidal and endoscope-assisted microsurgery) are reviewed, concerning operative instruments, surgical procedures, main indications and results.

Endoscopic third ventriculostomy is a safe and effective procedure for the treatment of Blake's pouch cyst

OBJECTIVE: Blake's pouch cyst (BPC) is a midline cystic malformation of the posterior fossa, within Dandy-Walker's complex (DWC), often associated with hydrocephalus. Endoscopic third ventriculostomy (ETV) has been an alternative to conventional methods for BPC treatment. This study aimed at reporting our experience with ETV in a series of patients with BPC. METHODS: Of 33 patients diagnosed with midline posterior fossa cyst, 26 met the protocol criteria for DWC, and eight subjects with BPC were selected (aged one month to two years old). All cases were treated with ETV. RESULTS: Five patients were male; and three were prenatally diagnosed. They had hydrocephalus and motor deficiencies. Motor assessment at a five-year follow-up yielded normal findings. All patients improved, and only one had residual cognitive dysfunction, despite overall neurological improvement. There were no complications. CONCLUSIONS: ETV was a safe and effective procedure, reducing risks and morbidity associated with open surgery and shunt-related problems.

Ascending transaqueductal cystoventriculoperitoneal shunting in Dandy-Walker malformation: technical note

The optimal treatment for Dandy-Walker malformation is still controversial. Ventriculoperitoneal shunting, cystoperitoneal shunting or combinations are the most common surgical options in the management of this clinical entity. Endoscopic procedures like ventriculocystostomy, 3rd ventriculostomy or endoscopy-assisted shunt surgeries have become the focus of recent publications. We describe a new transcystic endoscopic technique, with the usage of a single ascending transaqueductal shunt catheter with additional holes, whereby both the posterior fossa cyst and supratentorial ventricular compartments are drained effectively. By using this new technique complications associated with combined shunting can be avoided. In addition, by equalizing the pressure within the supra- and infratentorial compartments, the upward or downward herniations associated with single-catheter shunting can be prevented.

Hydrocephalus in Dandy-Walker malformation

INTRODUCTION

Even if the first description of Dandy-Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of "Dandy-Walker".

METHODS

An extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed.

CONCLUSION

The correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a "real" Dandy-Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

Treatment options for Dandy-Walker malformation

OBJECT

The aim of this study was to assess the efficacy of various treatment options available for children with Dandy-Walker malformation (DWM) and to evaluate the role of endoscopic procedures in the treatment of this disorder.

METHODS

The authors conducted a retrospective review of 72 children who underwent surgical treatment for DWM during a 16-year period. All patients underwent computed tomography scanning, and 26 underwent magnetic resonance (MR) imaging. The initial surgical treatment included ventriculoperitoneal (VP) shunt placement in 21 patients, cystoperitoneal (CP) shunt placement in 24, and combined VP and CP shunt insertion in three. Twenty-one patients underwent endoscopic procedures (endoscopic third ventriculostomy [ETV] alone in 16 patients, ETV with aqueductal stent placement in three, and ETV with fenestration of the occluding membrane in two). Three patients underwent membrane excision via a posterior fossa craniectomy. In the 26 patients who had undergone preoperative MR imaging, aqueductal patency was noted in 23 and aqueductal obstruction in three. These three patients underwent placement of a stent from the third ventricle to the posterior fossa cyst in addition to the ETV procedure. During the follow-up period, 12 patients with a CP shunt and four with a VP shunt experienced shunt malfunctions that required revision. Four patients with a CP shunt also required placement of a VP shunt. In addition, five of the 21 ETVs failed, requiring VP shunt insertion. A reduction in ventricle size noted on postoperative images occurred more frequently in patients with a VP shunt, whereas a reduction in cyst size was more appreciable in patients with a CP shunt. Successful ETV resulted in a slight decrease in ventricle size and varying degrees of reduction in cyst size.

CONCLUSIONS

Endoscopic procedures may be considered an acceptable alternative in children with DWM. The authors propose a treatment protocol based on preoperative MR imaging findings of associated aqueductal stenosis.

La malformation de Dandy-Walker

The aim of this review is to summarize our knowledge about Dandy-Walker malformation (DWM) and introduce recent notions about its prognosis. DWM is a malformation associating hypoplasia of the vermis, pseudocystic fourth ventricle, upward displacement of the tentorium, torcular and lateral sinuses and anterio-posterior enlargement of the posterior fossa. It is frequently associated with genetic anomalies, brain malformations (anomalies of gyration, grey matter heterotopias, meningoceles, corpus callosum agenesis...) or systemic malformations (heart, orthopedic, intestinal, urogenital and facial anomalies). It is also part of many syndromes. Its rarity, the difficulty of its diagnosis, the fact that the malformation is mainly known through hospitalized patients, mainly from neurosurgical departments, have made its definition variable and prevents us from having an accurate knowledge of its natural history and prognosis. Hydrocephalus, so frequent in neurosurgical series that some have included it in the definition, is actually rare as has been seen in prenatal series. Treatment, when necessary, is still controversial, the main options remaining cyst fenestration, ventriculo- and/or cystoperitoneal shunts and more recently endoscopic third ventriculostomy. The prognosis, commonly said to be unpredictable, is actually foreseeable after scrutinous observation of the brain anatomy, and mainly of the vermis. A cerebellar vermis with three groups of lobes and two main fissures, as identified on MRI T2 sagittal views, not only has the greatest chance to not be associated with other malformation but also to have a favorable neurocognitive outcome. On the contrary, a deeply dysgenetic vermis with only two or one recognizable lobes is not only constantly associated with other brain malformation but also with poor prognosis. This is a recent advance that may be important for those involved in prenatal counselling.

Diagnosis of inferior vermian hypoplasia by fetal magnetic resonance imaging: potential pitfalls and neurodevelopmental outcome

OBJECTIVE

Advances in fetal magnetic resonance imaging allow the detection of subtle anatomic anomalies of unclear long-term clinical significance. The purpose of this study was to examine the accuracy of fetal magnetic resonance imaging in the diagnosis of isolated inferior vermian hypoplasia and to describe the neurodevelopmental outcome.

STUDY DESIGN

We reviewed all cases with fetal and postnatal magnetic resonance imaging studies between 1999 and 2003 and identified 19 cases with a diagnosis of isolated inferior vermian hypoplasia. We compared prenatal and postnatal magnetic resonance imaging studies and evaluated subjects using developmental scales.

RESULTS

Isolated inferior vermian hypoplasia was confirmed by postnatal magnetic resonance imaging in 68% of the patients (13/19); the remaining 6 patients had normal postnatal magnetic resonance imaging results. On developmental testing at mean age 19.8 +/- 4.9 months, 3 infants (23%) with confirmed postnatal diagnosis demonstrated motor and language delays and functional difficulties, and 2 infants (15%) had behavioral problems; none of the infants with normal postnatal magnetic resonance imaging studies were delayed.

CONCLUSION

Isolated inferior vermian hypoplasia in the second trimester may be over-diagnosed by fetal magnetic resonance imaging and therefore warrants postnatal magnetic resonance imaging confirmation.

Endoscopic transtentorial ventriculocystostomy and cystoventriculoperitoneal shunt in a neonate with Dandy-Walker malformation and associated aqueductal obstruction

OBJECTIVE

Shunting of the lateral ventricle and the posterior fossa cyst is the advocated surgical therapy for children with Dandy-Walker malformation (DWM) and associated aqueductal obstruction. The high rate of complications of combined shunting stimulated the authors to search for an alternative surgical solution.

CLINICAL PRESENTATION/INTERVENTION

After transtentorial endoscopic ventriculocystostomy, a cystoventricular catheter, connected to a peritoneal shunt, was placed in a neonate with DWM and associated aqueductal obstruction. Immediately prior to ventriculocystostomy, the presence of a blocked third ventricular outflow was reconfirmed by contrast medium injection. Neuronavigation was required to define the surgical path from the lateral ventricle through the tentorium and the overlying small rim of brain parenchyma into the posterior fossa cyst. The postoperative clinical course was uneventful with radiologically proven reduction of the size of the ventricular system and the cyst.

CONCLUSION

Cystoventriculoperitoneal shunt placement after transtentorial endoscopic ventriculostomy is a surgical alternative in very young children with DWM and associated aqueductal obstruction.

Bilateral abducent and facial nerve palsies following fourth ventricle shunting: two case reports

CASE REPORTS

Treatment of isolated fourth ventricle syndrome is difficult and there is no widely agreed method. Fourth ventriculo-peritoneal shunting is the most commonly utilized procedure for the management of this syndrome. Complications from shunting are common and are usually related to malfunction, infection, dislocation and overdrainage. We present two unusual cases in which both patients developed bilateral abducens and facial nerve palsies following shunting of an isolated fourth ventricle. Magnetic resonance imaging (MRI) in both cases revealed collapse of the fourth ventricles with downward displacement of the brain stem. In the first case the trans-tentorial pressure difference was equilibrated with the aid of a "Y" connector between the supratentorial and infratentorial shunts, with full recovery of the neurological deficits; in the second case this approach failed and following a complicated neurosurgical course successful endoscopic aqueductal stenting was performed.

DISCUSSION

Pathogenesis of cranial nerve palsies following fourth ventricle shunting and the rationale of treatment are discussed and the literature is reviewed.

Endoscopic third ventriculostomy with cystoventricular stent placement in the management of dandy-walker malformation: technical case report of three patients

OBJECTIVE AND IMPORTANCE

Dandy-Walker malformation has conventionally been managed with placement of cystoperitoneal or ventriculoperitoneal shunts. However, associated aqueductal obstruction requires simultaneous drainage of both the supratentorial and infratentorial compartments.

CLINICAL PRESENTATION

Three children with Dandy-Walker malformation and aqueductal obstruction were managed with endoscopic third ventriculostomy and placement of a stent from the third ventricle to the posterior fossa cyst.

INTERVENTION

After an endoscopic third ventriculostomy was performed, the stent was placed from the third ventricle to the posterior fossa cyst through the thinnest part of the posteroinferior wall of the aqueduct. There was no operative morbidity. In one patient, the stent was malpositioned, requiring a repositioning. The endoscopic third ventriculostomy was successful in two patients, whereas it failed in one, requiring a ventriculoperitoneal shunt placement.

CONCLUSION

Cystoventricular stent placement with endoscopic third ventriculostomy is a promising alternative in patients with Dandy-Walker malformation with aqueductal obstruction.