Isolated Fourth Ventricle: To Shunt or Stent

Delayed symptomatic TFV in neonatal posthemorrhagic hydrocephalus-pathophysiology and therapeutic strategy: A case report and review of the literature

INTRODUCTION

Trapped fourth ventricle (TFV), which is a rare neurosurgical condition with multifactorial etiology, requires a prompt diagnosis and appropriate therapeutic method selection. We report a case of post-hemorrhagic hydrocephalus and TFV incited/worsened by prematurity, sepsis, acute respiratory distress syndrome (ARDS), mechanical ventilation, and concomitant fourth ventricle outlets stenosis; which displayed a delayed onset. This article addresses the proposed pathophysiology and the clinical importance of appropriate therapeutic strategies with a mini-review of the literature.

CASE PRESENTATION

We encountered a case involving a premature Asian male newborn with sepsis and posthemorrhagic hydrocephalus who required ventriculoperitoneal shunt surgery. However, after three years, the baby was diagnosed with a trapped fourth ventricle and subsequently underwent retrograde endoscopic surgery with stent insertion.

DISCUSSION

TFV is traditionally known as a complication of lateral ventricle shunting. However, in rare cases such as our neonate patient, it develops as a consequence of multiple pathophysiological processes including ventricular system inflammation along with associated anatomic and physiologic alterations, which necessitates prompt diagnosis and a case-specific therapeutic strategy.

CONCLUSION

Understanding the multifactorial pathophysiological mechanisms leading to the development of TFV is crucial. The presence of comorbidities such as prematurity, neonatal sepsis, and ARDS increased the risk of intraventricular hemorrhage and subsequent inflammation and further exacerbated obstructions in cerebrospinal fluid pathways. When posthemorrhagic TFV is accompanied by collapsed lateral ventricles, the optimal treatment approach is retrograde endoscopic fenestration with stent insertion. This treatment option has proven effective in alleviating the condition and restoring proper cerebrospinal fluid flow.

Endoscopic transaqueductal stent placement for tumor-related aqueductal compression in pediatric patients: surgical consideration, technique, and results

PURPOSE

Endoscopic transaqueductal stenting has become a well-accepted treatment option for a selected small subset of aqueductal stenosis-related obstructive hydrocephalus. However, transaqueductal stenting poses unique challenges and risks which requires critical consideration. This report discusses the clinical experiences with transaqueductal stenting for periaqueductal tumor-related aqueductal stenosis focusing on pediatric patients.

METHODS

A retrospective analysis of all patients undergoing endoscopic TAS from 01/1993 to 01/2022 in the author's departments was performed. Demographic, clinical, radiological, and intraoperative endoscopic data were evaluated. All patients with AS-related occlusive hydrocephalus that was treated with TAS were analyzed and prospectively followed. Special attention has been given to providing insights into indications, surgical technique, and limitations.

RESULTS

Out of 28 endoscopic transaqueductal endoscopis stenting procedures, five procedures were performed on periaqueductal tumor-related obstructive hydrocephalus, two children and three adult patients. CSF pathway was obstructed by tumor located in the aqueduct in 2, by tumor in the thalamus/mesencephalon in 1, by a tumor within the third ventricle in 1, and by a tumor of the lamina tecti in 1. Simultaneously with transaqueductal stenting, 2 endoscopic third ventriculostomies (ETV), 3 tumor biopsies, and 1 tumor resection were performed. Postoperative complications included the following: CSF fistula (1 case), and asymptomatic fornix contusion (1 case). A working aqueductal stent was achieved in all cases based on clinical follow-up evaluation. Postoperatively, all patients showed improvement or resolution of their symptoms. The mean follow-up period was 25.2 months (range, 1-108 months). One patient died due to tumor progression during early follow-up. No stent migration was seen.

CONCLUSION

Endoscopic third ventriculostomy remains the gold standard for treatment of CSF circulation obstructions with lesions in the posterior third ventricle and aqueduct. Transaqueductal stenting for periaqueductal tumor-related aqueductal compression is technically feasible. However, because of the potential high risks and subtle advantages compared with ETV transaqueductal stenting, it might be indicated in a small subset of well-selected patients if alternative treatment options are not at hand.

Trapped fourth ventricle: to stent, shunt, or fenestrate-a systematic review and individual patient data meta-analysis

Trapped or isolated fourth ventricle (TFV) is a rare but critical neurosurgical condition, mostly occurring in pediatric patients, caused by a blockage of the in- and outlets of the fourth ventricle. The purpose of this study is to review all available data on the treatment options of TFV and to compare their safety, efficacy, and durability. MEDLINE, Embase, and Google Scholar were searched from inception to September 13, 2022, for prospective or retrospective cohorts, case-control studies, case series or case reports, reporting detailing outcomes of TFV patients, treated with an endoscopic-, microsurgical-, shunt placement,- or hybrid approaches to TFV. All authors were contacted to provide individual patient data. Eighty-seven articles (314 patients) were included in the individual patient data meta-analysis (IPD) and 9 (151 patients) in the cohort meta-analysis. The IPD revealed that primary endoscopic (aOR 0.21; [95% CI 0.08-0.57]) and microsurgical interventions (aOR 0.21; [95% CI 0.05-0.82]) were associated with a significantly lower revision rate, compared to shunt placement, when adjusted for confounders. Endoscopy was also associated with a significantly higher rate of clinical improvement (aOR 4.56; [95% CI 1.2-18]). The meta-analysis revealed no significant difference in revision rate between the endoscopic (0.33 [95% CI 0.0-0.52]) and shunt group (0.44 [95% CI 0.0-1.0]). Endoscopy should be considered as the first-line treatment of TFV due to its superior efficacy, durability, and similar safety, compared to shunt placement and its minimally invasive nature. Microsurgery should be considered as a second treatment option, due to its similar clinical outcomes and revision rate as endoscopy, but it is more invasive in nature.

FOURTH VENTRICLE ENTRAPMENT MANAGEMENT AND ITS OUTCOMES: CASE-SERIES FROM A SINGLE NEUROSURGERY CENTER

This case-series aims to report the elaborate management of FVEs in our center and their outcome. Data from 2017 to 2022 were retrospectively collected. We reviewed patient's demography, clinical findings, radiology results, operative procedures, and complications after surgery. Five patients with FVE diagnosis underwent neurosurgical procedures. The procedures include VP shunt, endoscopic cyst fenestration and fourth ventricle peritoneal shunt (FVPS). Out of five patients, 3 had favorable outcomes, 1 deceased, and 1 patient were still hospitalized. The underlying diseases varied from hemorrhage, cyst, infection, congenital, and neoplasm. FVE etiologies range from congenital to intraventricular hemorrhage complications and infection. VPS, FVPS, and endoscopic treatment with stenting or fenestration are surgical options for treating FVE patients. CSF diversion using shunt device is the simplest procedure. Patients with FVE in general have favorable outcome after CSF diversion of any method.

Radiologic and clinical outcome of isolated fourth ventricle following post-hemorrhagic hydrocephalus in children

PURPOSE

Few studies report radiologic and clinical outcome of post-hemorrhagic isolated fourth ventricle (IFV) with focus on surgical versus conservative management in neonates and children. Our aim is to investigate differences in radiological and clinical findings of IFV between patients who had surgical intervention versus patients who were treated conservatively.

METHODS

A retrospective analysis of patients diagnosed with IFV was performed. Data included demographics, clinical exam findings, surgical history, and imaging findings (dilated FV extent, supratentorial ventricle dilation, brainstem and cerebellar deformity, tectal plate elevation, basal cistern and cerebellar hemisphere effacement, posterior fossa upward/downward herniation).

RESULTS

Sixty-four (30 females) patients were included. Prematurity was 94% with 90% being < 28 weeks of gestation. Mean age at first ventricular shunt was 3.6 (range 1-19); at diagnosis of IFV, post-lateral ventricular shunting was 26.2 (1-173) months. Conservatively treated patients were 87.5% versus 12.5% treated with FV shunt/endoscopic fenestration. Severe FV dilation (41%), severe deformity of brainstem (39%) and cerebellum (47%) were noted at initial diagnosis and stable findings (34%, 47%, and 52%, respectively) were seen at last follow-up imaging. FV dilation (p = 0.0001) and upward herniation (p = 0.01) showed significant differences between surgery versus conservative management. No other radiologic or clinical outcome parameters were different between two groups.

CONCLUSION

Only radiologic outcome results showed stable or normal FV dilation and stable or decreased upward herniation in the surgically treated group.

The entity of the trapped fourth ventricle: A review of its history, pathophysiology, and treatment options

An isolated or trapped fourth ventricle is a relatively rare, although serious, adverse effect of hemorrhagic, infectious, or inflammatory processes that involve the central nervous system. This entity usually occurs after successful shunting of the lateral ventricles and may become clinically evident with the development of delayed clinical deterioration. This decline of the neurological status of the patient is evident after an initial period of improvement of the relevant symptoms. Surgical treatment options include cerebrospinal fluid shunting procedures, along with open surgical and endoscopic approaches. Complications related to its management are common and are related with obstruction of the fourth ventricular catheter, along with cranial nerve or brainstem dysfunction. We used the keywords: "isolated fourth ventricle," and "trapped fourth ventricle," in PubMed^® and Web of Science^®. Treatment of the trapped fourth ventricle remains a surgical challenge, although the neurosurgical treatment armamentarium has broadened. However, prompt recognition of the clinical and neurological findings that accompany any individual patient, in conjunction with the relevant imaging findings, is mandatory to organize our treatment plan on an individual basis. The current experience suggests that any individual intervention plan should be mainly based on the underlying pathological substrate of hydrocephalus. This could help us to preserve the patient's life, on an emergent basis, as well as to ensure an uneventful neurological outcome, maintaining at least the preexisting level of neurological function.

Endoscopic aqueductoplasty and stenting in the treatment of isolated fourth ventricle in children: 20-year institutional experience

BACKGROUND

Endoscopic aqueductoplasty with aqueductal stenting is an effective surgical procedure for the treatment of isolated fourth ventricle (IFV). Due to the rarity of the underlying pathology, it can be considered a rare procedure that can be performed with different surgical techniques and approaches.

OBJECTIVES

To assess long-term functioning of permanent aqueductal stents implanted in children affected by hydrocephalus and IFV and to describe some variations of the same procedure.

METHODS

We reviewed retrospectively all the patients presenting at our institution in the years 1999-2019 for symptoms of isolated fourth ventricle who underwent a surgical procedure of endoscopic aqueductoplasty and/or aqueductal stent. Surgical reports, radiological images, and surgical videos were retrospectively analyzed.

RESULTS

Thirty-three patients with symptomatic isolated fourth ventricle (IFV) underwent fifty (50) neuroendoscopic procedures in the period observed. The median age of the patients at the time of first surgery was 7 months, with 22 premature babies. In twenty-nine patients (87.8%), a precoronal approach was performed, while four patients received a suboccipital burr hole. Ten patients were never reoperated since. Twenty-three patients underwent further surgeries: a new aqueductoplasty with aqueductal stent was performed in 13 cases. The remaining 10 patients required a combination of other procedures for management of hydrocephalus. Long-term follow-up showed a permanent stent functioning rate of 87% at 2 years and 73% at 4 years, remaining stable afterwards at very long term (20 years).

CONCLUSION

Endoscopic aqueductoplasty and stenting is a reliable procedure in the long-term management of isolated fourth ventricle.

Proposed radiological score for the evaluation of isolated fourth ventricle treated by endoscopic aqueductoplasty

PURPOSE

Evidence supporting the effectiveness of endoscopic aqueductoplasty (EA) for the treatment of isolated fourth ventricle (IFV) is limited to small surgical series of cases. Additionally, studies adopted different radiological outcome criteria, which makes it difficult to compare outcomes accurately. Thus, we aimed to develop a radiological score (RS) as an alternative assessment method for EA.

METHODS

The cases of 20 consecutive pediatric patients harboring IFV and treated by EA were retrospectively reviewed. Clinical data and pre- and 1-year postoperative brain images were analyzed. The RS was based on the enlargement of the fourth ventricle and deformation of the cerebellum and brainstem. After randomization, three experts, blinded to patient outcomes, analyzed the brain images and established a consensus for the values of the score. Outcomes were validated by comparing the maximum anteroposterior distance of the fourth ventricle using the RS, pediatric functional status score, and clinical symptoms.

RESULTS

The RS was strongly correlated with the anteroposterior distance of the fourth ventricle (Pearson's coefficient = 0.78), and the mean RS dropped from 6.15 to 3.90 (p < 0.001) 1 year after EA. Upward extension (p = 0.021) and brainstem deformation (p = 0.010) were the most significant improved features. There was agreement among RS and symptom improvement in 16 children (80%) and the pediatric functional status score in 14 children (70%).

CONCLUSION

In this study, the proposed radiological score proved to be an accurate tool for the evaluation of IFV treatment with EA.

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.

Trapped fourth ventricle-treatment options and the role of open posterior fenestration in the surgical management

BACKGROUND

Trapped fourth ventricle (TFV) is a rare and difficult to treat condition. Most patients have a past inciting event (infection, IVH, trauma) and history of prior CSF diversion. The symptoms are due to the mass effect on brainstem and cerebellum. Rarely, TFV can also be associated with syrinx formation due to a dissociated craniospinal CSF flow near the fourth ventricle outlets. We present our experience and outcomes of open posterior fenestration in 11 cases, along with an overview of the surgical management of TFV.

METHODS

Between 2011 and 2018, 11 patients of TFV were operated by the posterior approach fenestration of the fourth ventricle outlets and arachnoid dissection. The clinical and radiological findings of the patients were retrieved from the hospital database. The surgical technique is described in detail. The patients' neurological status and imaging findings in the follow-up were recorded and compared.

RESULTS

The average age of the patients was 23.55 years. The most common presenting symptoms were headache (9/11) and gait imbalance (7), with TB meningitis being the commonest etiology. Ten patients had a history of prior CSF diversion with two presenting with shunt malfunction. Mean follow-up duration was 33.33 months. The improvement in neurological status was observed in 9/11 patients, 2 remained status quo. On follow-up imaging, 8/11 (72.72%) patients had a decrease in the size of TFV while syrinx improved in 3/5 (60%).

CONCLUSION

Multiple surgical approaches have been described for TFV. Endoscopic fourth ventriculostomy with aqueductoplasty is gaining popularity in the past two decades. However, an open posterior fenestration of the midline fourth ventricle outlet (magendieplasty) along with sharp arachnoid dissection (adhesiolysis) along the cerebello-medullary cisterns and paracervical gutters is relatively simple and provides physiological fourth ventricular CSF outflow. This is especially useful in TFV with syrinx as the craniospinal CSF circulation is established.

Trapped fourth ventricle: a rare complication in children after supratentorial CSF shunting

PURPOSE

Trapped fourth ventricle (TFV) is a well-identified problem in hydrocephalic children. Patients with post-hemorrhagic hydrocephalus (PHH) are mostly affected. We tried to find out predisposing factors and describe clinical findings to early diagnose TFV and manage it.

METHODS

We reviewed our database from 1991 to 2018 and included all patients with TFV who required surgery. We analyzed prematurity, cause of hydrocephalus, type of valve implanted, revision surgeries, modality of treatment of TFV, and their clinical examination and MRI imaging.

RESULTS

We found 21 patients. Most of patients suffered from PHH (16/21), tumor (2/21), post-meningitis hydrocephalus (2/21), and congenital hydrocephalus (1/21). Seventeen patients were preterm. Seven patients suffered from a chronic overdrainage with slit ventricles in MRI. Thirteen patients showed symptoms denoting brain stem dysfunction; in 3 patients, TFV was asymptomatic and in 5 patients, we did not have available information regarding presenting symptoms due to missing documentation. An extra fourth ventricular catheter was the treatment of choice in 18/21 patients. One patient was treated by cranio-cervical decompression. Endoscopic aqueductoplasty with stenting was done in last 2 cases.

CONCLUSION

Diagnosis of clinically symptomatic TFV and its treatment is a challenge in our practice of pediatric neurosurgery. PHH and prematurity are risk factors for the development of such complication. Both fourth ventricular shunting and endoscopic aqueductoplasty with stenting are effective in managing TFV. Microsurgical fourth ventriculostomy is not recommended due to its high failure rate. Early detection and intervention may help in avoiding fatal complication and improving the neurological function.

Endoscopic Fourth Ventriculostomy: Suboccipital Transaqueductal Approach for Fenestration of Isolated Fourth Ventricle: Case Report and Technical Note

BACKGROUND

Trapped or isolated fourth ventricle is a known, late sequela after lateral ventricular shunt placement for hydrocephalus, particularly after infection or hemorrhage. It may cause brainstem compression and insidiously present with ataxia, dysarthria, and intracranial hypertension, further delaying diagnosis. There is no universally agreed on treatment algorithm, and options include open fenestration through a suboccipital craniotomy, fourth ventricle shunting, and minimally invasive options including endoscopic stenting and fenestration through a precoronal approach.

CASE DESCRIPTION

We describe a young child with epilepsy and symptomatic brainstem compression from a dilated fourth ventricle, with a history of streptococcal parietal abscess and posthemorrhagic hydrocephalus requiring shunt placement. Given his history of infection and nearly neurologically intact examination, we pursued minimally invasive endoscopy through a suboccipital, transaqueductal approach to fenestrate his fourth ventricle.

CONCLUSIONS

Magnetic resonance imaging (MRI) demonstrated complex, loculated hydrocephalus and a dilated fourth ventricle. Under electromagnetic navigation, we endoscopically fenestrated his fourth ventricle using a rarely described suboccipital, transaqueductal approach. He tolerated the procedure without complication and improved neurologically, although his follow-up MRI demonstrated no change in fourth ventricular dilation at 1 year. Although there was no decrease in size of the fourth ventricle on follow-up MRI, we describe an alternative, well-tolerated, suboccipital approach for the management of a trapped fourth ventricle. Fenestration of a web of tissue in the aqueduct of Sylvius provided long-term clinical improvement and may provide a rescue approach for patients who are not candidates for standard approaches.

Reversible Progressive Multiple Cranial Nerve Paresis in the Isolated Fourth Ventricle following Placement of Fourth Ventricle Shunt: Case Report and Review of the Literature

BACKGROUND/AIMS

Multiple lower cranial nerve paresis occurring after placement of a fourth ventricle shunt for an isolated fourth ventricle is an uncommon complication in the postoperative period. Of the various etiologies, direct brain stem injury by the catheter and rapid decompression of the fourth ventricle by the shunt causing traction on the cranial nerves have been reported in the literature.

METHODS

We report the case of a 9-year-old girl with an isolated fourth ventricle who developed bilateral facial and multiple lower cranial nerve paresis with bilateral internuclear ophthalmoplegia a month after placement of a ventriculoperitoneal shunt. The postprocedure MRI showed a well-decompressed fourth ventricle with catheter tip located along the long axis of the fourth ventricle.

RESULTS

She was managed non-operatively. She improved gradually in her cranial nerve paresis over the next 3 months and completely recovered at 9 months.

CONCLUSION

We believe the reversible multiple cranial nerve neuropathies resulted from acute decompression of the fourth ventricle following the shunt insertion. A gradual decompression of the dilated fourth ventricle by an aqueductal stent or a high-pressure shunting system could prevent this potential complication.

Feasibility of a Fourth Ventriculopleural Shunt for Diversion of an Isolated Fourth Ventricle: A Technical Note

Isolated fourth ventricle syndrome is an uncommon entity due to obstruction of both inlet and outflow foramina. The resulting mass effect from the progressively expanding fourth ventricle may cause symptoms from both cerebellar and brainstem compression. Although a variety of treatment modalities have been advocated for this condition, an in-depth description of placement of a fourth ventriculopleural (VPL) shunt from a single-stage prone approach has not yet been published in the literature. We describe here a case of successful placement of a fourth VPL shunt in a 22-year-old female with a history of a prior posterior fossa pilocytic astrocytoma resection who presented with symptomatic isolated fourth ventricular hydrocephalus.