BACKGROUND: Entrapment of the temporal horn (TH) is rare condition that can lead to increased intracranial pressure, but there is no consensus on a standard treatment. The aim of this study was to conduct a systematic literature review of the reported cases of TH entrapment and describe our operative technique for endoscopic fenestrations of the lateral ventricle into the basal cisterns.
METHODS: We searched the databases Pubmed and Google scholar to find all studies reporting cases of entrapped TH and the subsequent treatment. Additionally, we report two illustrative cases of endoscopic fenestration with a step-by-step description of our surgical technique.
RESULTS: Twenty-nine studies with a total of 67 patients were included in the analysis. The mean age was 36.5 years (SD± 21.9), and the female-to-male ratio was 1.5. The most frequent cause of TH entrapment was post-surgical scarring after tumor surgery (n= 30), and the most commonly reported treatment modality was endoscopic fenestration of the TH (n = 14). We observed an increasing use of endoscopic fenestration over time.
CONCLUSIONS: Entrapped TH is a rare condition often requiring surgical treatment. Neuronavigation-guided endoscopic fenestration of the ventricle into the basal cisterns appears to be a safe, efficient, and device-free technique that has gained importance over the past years.

Introduction  Hydrocephalus is a condition characterized by the abnormal accumulation of cerebrospinal fluid within the brain\'s ventricular system. It can stem from obstructive and nonobstructive causes. Pregnancy introduces physiopathological changes that may heighten the risk of developing or worsening symptomatic hydrocephalus. Nevertheless, comprehensive reports on this aspect, especially regarding surgical interventions, remain scarce. Case Report  A young woman with a history of recurrent headaches experienced a worsening of her symptoms at the onset of her pregnancy. A magnetic resonance imaging (MRI) in the first trimester revealed increased ventricular dilation, indicating an obstructive cause due to aqueduct stenosis. During a neurosurgical board meeting, treatment options were discussed, considering the identifiable obstruction, the heightened intra-abdominal pressure associated with pregnancy, and the risk of ventricular shunt dysfunction. The patient underwent an endoscopic third ventriculostomy (ETV) without complications, leading to both symptom relief and a successful conclusion to the pregnancy. Discussion  Neurosurgical procedures in pregnant women are uncommon due to the increased risks to both the mother and the fetus. However, when performed by a qualified multidisciplinary team, they can lead to positive outcomes. In cases of hydrocephalus during pregnancy, ETV appears to be a viable alternative for surgical intervention, particularly when hydrocephalus becomes symptomatic and an obstructive cause is identified, whether in patients with existing shunts or those with newly developed hydrocephalus.

A developmental venous anomaly (DVA) is a venous drainage of the associated parenchyma that is normally asymptomatic. However, a DVA located adjacent to the aqueduct can cause obstructive hydrocephalus by blocking the flow of cerebrospinal fluid. We describe a rare case of obstructive hydrocephalus due to aqueductal stenosis secondary to a DVA. A 43-year-old man presented with sudden bilateral temporal pain during weight training. Using a 3-Tesla scanner, cranial magnetic resonance imaging (MRI) was performed, and hydrocephalus was found with mild enlargement of the lateral and third ventricles. Susceptibility-weighted imaging and postcontrast MRI revealed that the DVA from the bilateral thalami narrowed the orifice of the aqueduct on its drainage route towards the vein of Galen. We assumed that force exerted during weight training may have caused dilation of the anomalous veins, leading to his symptom. A review of the relevant English-language literature yielded only 19 cases of aqueductal stenosis due to DVA. In comparison to these cases, the duration of symptom in our case was extremely short because the patient had a history of ventriculomegaly detected on plain computed tomography and was diagnosed quickly based on the characteristic finding of DVA: the caput medusae appearance.

Subependymomas are benign tumors of the ventricles that grow from the ventricular wall into the cerebrospinal fluid spaces within the brain, obstructing the flow of the cerebrospinal fluid and causing obstructive hydrocephalus. It is estimated that ependymomas represent between 0.2% and 0.7% of all intracranial tumors. They arise most frequently in the fourth ventricle (50-60%) and the lateral ventricles (30-40%). We present the case of a 50-year-old patient, previously diagnosed with an intraventricular process, admitted in our clinic. At neurological examination, the patient was cooperative, bradylalic, and bradypsychic, with right hemiparesis, postural and balance disorders, and occasionally sphincteric incontinence. MRI with contrast described a left intraventricular tumor, in the frontal horn of the left lateral ventricle with homogeneous appearance, with a maximum diameter of 50 mm and base of insertion at the adjacent ependyma of the foramen of Monro, which determined obstructive hydrocephalus. Total resection of the left intraventricular cerebral tumor was achieved. Histopathological analysis revealed a subependymoma. Postoperative recovery was slowly favorable, with significant neurological improvement. At neurological examination at three-month follow-up, the patient\'s right hemiparesis and unsystematized balance disorders improved. A contrast-enhanced CT scan was performed, highlighting left frontal sequelae hypodensity corresponding to the operated tumor, enlarged left lateral ventricle without active hydrocephalus, and no sign of tumor recurrence. At six-month follow-up, clinico-radiologic findings coincide with those from three-month follow-up. Subependymomas are slow-growing (grade 1) tumors and generally have a favorable prognosis. Unfortunately, due to their anatomical level, multiple complications can arise, caused from obstructive hydrocephalus complications, such as cognitive dysfunction and incontinence. Tumor resection should be complete, a successful operation being a challenge for every neurosurgeon.

Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) are surgical methods for treating obstructive hydrocephalus. However, there is still disagreement regarding the most effective technique, in terms of both operative success and postoperative complications. Therefore, we performed a systematic review and meta-analysis to compare the efficacy and safety of these two methods in patients with obstructive hydrocephalus. We performed a systematic search of the PubMed, Scopus, and Cochrane Library databases. Randomized clinical trials (RCTs) comparing ETV and VPS in pediatric or adult patients with obstructive hydrocephalus were included. The outcomes included were operative success, postoperative cerebrospinal fluid leak, postoperative infection, postoperative or intraoperative bleeding, blockage rate, and mortality. The risk ratio (RR) was calculated with a 95% confidence interval (CI). Heterogeneity was evaluated with I 2 statistics. We used a fixed-effects model for outcomes with I 2  < 25% and DerSimonian and Laird random-effects model for other conditions. The Cochrane collaboration tool for assessing the risk of bias in randomized trials was used for risk-of-bias assessment. R, version 4.2.1, was used for statistical analyses. Of the 2,353 identified studies, 5 RCTs were included, involving 310 patients with obstructive hydrocephalus, of which 163 underwent ETV. There was a significant difference in favor of ETV for postoperative infection (risk ratio [RR]: 0.11; 95% confidence interval [CI]: 0.04-0.33; p  < 0.0001; I 2  = 0%) and blockage rate (RR: 0.15; 95% CI: 0.03-0.75; p  = 0.02; I 2  = 53%). Meanwhile, there was no significant difference between groups for the postoperative or intraoperative bleeding (RR: 0.44; 95% CI: 0.17-1.15; p  = 0.09; I 2  = 0%), postoperative cerebrospinal fluid leak (RR: 0.65; 95% CI: 0.22-1.92; p  = 0.44; I 2  = 18%), operative success (RR: 1.18; 95% CI: 0.77-1.82; p  = 0.44; I 2  = 84%), and mortality (RR: 0.19; 95% CI: 0.03-1.09; p  = 0.06; I 2  = 0%). Three RCTs had some concerns about the risk of bias and one RCT had a high risk of bias due to the process of randomization and selection of reported results. Thus, this meta-analysis of RCTs evaluating ETV compared with VPS demonstrated that although there is no superiority of ETV in terms of operative success, the incidence of complications was significantly higher in patients who underwent VPS. Our results suggest that the use of ETV provides greater benefits for the treatment of obstructive hydrocephalus. However, more RCTs are needed to corroborate the superiority of ETV.

Colloid cysts are benign growths commonly found in the third ventricle at the foramen of Monro. They can be asymptomatic or present with a variety of symptoms, including headaches, diplopia, memory problems, psychosis, urinary incontinence, and ataxia. Obstructive hydrocephalus from a colloid cyst is caused by a blockage of cerebral spinal fluid (CSF) from the lateral ventricles at the foramen of Monro. Colloid cysts have rarely been reported to cause sudden death. Here we present the case of a 32-year-old female with a known history of a colloid cyst who presented with a headache and transient weakness in her lower extremities noted while climbing stairs.

Although choroid plexus cysts are a frequent incidental neuroimaging finding, symptomatic ones are rare-a series of more than five cases are hard to find. In the absence of high-volume studies, there are no generally accepted algorithms for diagnosis and treatment for this pathology. Proposed surgical techniques include microsurgical excision or fenestration and endoscopic excision or fenestration with or without additional shunting. No definitive conclusions exist about the superiority of a certain technique. Here, we introduce an illustrative case of a patient with a symptomatic choroid plexus cyst in the trigone of the lateral ventricle and a systematic review of 65 additional published cases with the aim of identifying epidemiological features, variants of localization of the cysts, their symptoms, persistence of concomitant obstructive hydrocephalus, and treatment modalities. A PRISMA-based literature search was performed on the PubMed, MEDLINE, Scopus, and Web of Knowledge databases. We include in the review case reports and case series of symptomatic choroid plexus cysts with full texts or valuable abstracts available online in English and published by April 2023. All abstracts of retrieved studies were assessed by two independent researchers to avoid bias. Only descriptive statistics were used for the presentation of the results. A total of 48 studies (39 case reports and 9 case series) with 65 depicted cases met the eligibility criteria. The review showed a slight predominance of choroid plexus cysts in men. The most common localizations of cysts were the trigone and the body of the lateral ventricle. Obstructive hydrocephalus is often present in patients with choroid plexus cysts. The most common symptoms of cysts were signs of increased ICP: headaches and vomiting. The main treatment approaches for symptomatic choroid plexus cysts were microsurgical excision, microsurgical fenestration, endoscopic fenestration, and total endoscopic excision. The tendency has been noted to shift from microsurgical to endoscopic procedures over the past two decades. Some data on the classification of cysts of the central nervous system and the underlying mechanisms of the pathogenesis of choroid plexus cysts are also presented.Although symptomatic cases of choroid plexus cysts are rare, by summarizing currently available data, one could clarify their common features and identify a preferable treatment modality.

Primary leptomeningeal medulloblastoma (PL-MB) in adults is a rare disease with a severe prognosis. A 35-year-old woman presented with headaches, diplopia, and gait ataxia, with triventricular hydrocephalus and descent of the cerebellar tonsils beyond the foramen magnum. Endoscopic third ventriculostomy was performed. Six months later, headaches recurred. Dilatation of the supratentorial ventricular system and massive cerebellar swelling without contrast-enhancing nodularities were reported. Occipitocervical decompression with duraplasty was performed. A bioptic diagnosis of PL-MB was made. Craniospinal irradiation and chemotherapy were administered. After 18 months, no recurrence was observed. Few cases of PL-MB have been reported: patients die before treatment or within a few days after surgery. Our long-term survival could be ascribable to a slow clinical presentation and an early diagnosis that allowed surgical treatment and the administration of a combined chemoradiotherapy protocol. Cerebellar swelling, even without associated enhancing lesions, with or without hydrocephalus, should be a neuroradiological alarm sign, and PL-MB should be considered.

UNASSIGNED: Cerebellar hemangioblastoma is a highly vascular benign tumor and the growth rate of hemangioblastomas is believed to often accelerate during pregnancy; however, the reason for this rapid increase in size remains poorly understood. There are several case reports of symptomatic hemangioblastoma during pregnancy; however, the favorable management strategy has not been well established.
UNASSIGNED: A 35-year-old woman, gravida 2 para 1, with no significant medical history presented with vertigo and difficulty walking at around 11 weeks of pregnancy and was referred to our institute at 30 weeks of gestation because of worsening symptoms. Brain magnetic resonance imaging revealed a 5.6 cm cystic lesion with a mural nodule in the right cerebellar hemisphere and the lesion blocked cerebrospinal fluid drainage from the fourth ventricle and brainstem, resulting in obstructive hydrocephalus. After obtaining the patient\'s consent, a multidisciplinary team consisting of obstetricians and neurosurgeons decided to perform resection of the intracranial lesion following delivery of the fetus by emergency cesarean section in view of the symptoms of increased intracranial pressure. The patient\'s general condition was confirmed to be stable postoperatively and she was discharged on the 16th day of her hospitalization without any neurological deficits or fetal complications.
UNASSIGNED: Urgent tumor resection combined with cesarean section can be planned once fetal lung maturity is confirmed. Most cases of symptomatic hemangioblastoma during pregnancy have an uneventful gestational course and a favorable outcome for both mother and child.

Holmes tremor (HT) is a rare and debilitating movement disorder comprising both rest and action tremor, and it is known for its resistance to treatment. Its most common causes include ischemic or hemorrhagic insults and trauma. Mechanistically, the combined rest and action tremor is thought to require a double lesion of both the dopaminergic nigrostriatal system and the dentatorubrothalamic pathways, often near the midbrain where both pathways converge. The aim of this study was to characterize HT as a presenting sign in cases of hydrocephalus and to discuss potential pathomechanisms, clinical presentations, and treatment options.
MEDLINE and Web of Science were searched for cases of HT with hydrocephalus from database inception to August 2021, and these were compiled along with the authors\' own unique case of treatment-responsive HT in a child with low-pressure obstructive hydrocephalus secondary to a tectal tumor. Patient characteristics, presenting signs/symptoms, potential precipitating factors, interventions, and patient outcomes were recorded.
Nine patients were identified including the authors\' video case report. All patients had a triventriculomegaly pattern with at least a component of obstructive hydrocephalus, and 4 patients were identified as having low-pressure hydrocephalus. Parinaud\'s syndrome and bradykinesia were the most commonly associated signs. Levodopa and CSF diversion were the most commonly used and effective treatments for HT in this population. This review was not registered and did not receive any funding.
HT is a poorly understood and probably underrecognized presentation of hydrocephalus that is difficult to treat, limiting the strength of the evidence in this review. Treatment options include CSF diversion, antiparkinsonian agents, antiepileptic agents, deep brain stimulation, and MR-guided focused ultrasound, and aim toward the nigrostriatal and dentatorubrothalamic pathways hypothesized to be involved in its pathophysiology.