Giant tumefactive mesencephalothalamic Virchow-Robin space with triventricular hydrocephalus: a case-based systematic literature review.

BACKGROUND: The perivascular spaces of the brain are also known as Virchow-Robin spaces (VRSs). Dilated Virchow-Robin spaces in the brainstem are rare and mainly cause symptoms due to obstructive hydrocephalus, less frequently because of their size, mass effect, and impact on eloquent structures. CASE ILLUSTRATION: We present a patient with giant tumefactive VRS with hydrocephalus and neurological symptoms who was treated with endoscopic third ventriculostomy (ETV) followed by microscopic cyst fenestration. On the basis of this observation, we performed a thorough review of the literature to evaluate different treatment options. RESULTS: An 11-year-old girl presented with a headache for 3 months. The patient had a giant tumefactive mesencephalothalamic VRS with triventricular hydrocephalus. She was initially treated with endoscopic third ventriculostomy and multiple cyst fenestration. Symptomatic cyst regrowth required multiple cyst fenestrations via transcallosal transchoroidal (N = 2) and subtemporal approaches (N = 1) at the 2- and 4-year follow-ups. A literature review of these conditions allowed the detection of 12 cases (including our index case), and only 25% (3/12) of the patients underwent cyst fenestration 16.7% (2/12) required endoscopic fenestration and 8.3% (1/12) required microscopic fenestration. CONCLUSION: Giant mesencephalothalamic dVRSs are rare in the pediatric population. These patients are usually symptomatic due to obstructive hydrocephalus. Surgical options are endoscopic third ventriculostomy, ventricular shunt procedures, or direct cyst fenestration (microscopic or endoscopic). Close follow-up is mandatory owing to the risk of progression of the disease. Cyst fenestration resolves symptoms immediately, as it addresses both hydrocephalus and mass effects due to the cystic lesion in the same setting.

Low-grade epilepsy-associated tumors: Epilepsy outcome and antiseizure medication discontinuation after lesionectomies as first-line surgical approach in pediatric population.

OBJECTIVE: This study aimed to evaluate epilepsy outcome and antiseizure medication (ASM) discontinuation after lesionectomies as first surgical approach in pediatric population diagnosed with low-grade epilepsy-associated neuroepithelial tumors (LEATs). METHODS: We conducted a retrospective study. Thirty-six consecutive patients with histological diagnoses of LEATs who underwent surgery between 2018 and 2021 at our institution were included. The clinical and surgical data were retrospectively analyzed. RESULTS: Thirty (83.3%) of 36 patients are free of disabling seizures (Engel class I) and 19 (63,4%) of them are classified as Engel Ia. In 17 (47.2%) patients, ASM could be discontinued. The mean age at surgery was 8.6 years (±4.04) and the mean age at onset of epilepsy was 7.2 years (±3.8), whereas the mean duration of epilepsy in months at the time of surgery was 21.3 months (±23.7). The epileptogenic tumor was in the temporal lobe in 20 (55.5%) patients. Because of seizure persistence, a second or a third surgery was necessary for six patients (16.7%) and four of them had residual lesions (three in temporal and one in extratemporal site). No perioperative complications were recorded, including acute seizures, with a median hospitalization time of 7 days. Shorter epilepsy duration at time of surgery as long as a single ASM was significantly correlated with an Engel class I outcome (p-value = .01 and p-value = .016, respectively). Focal seizure semeiology was associated with an increased probability of antiseizure medication discontinuation (p-value = .042). SIGNIFICANCE: Our findings confirm that shorter epilepsy disease duration, monotherapy before surgery, and seizure semeiology are determinant factors for a positive seizure outcome and medication discontinuation, also with less invasive surgical approaches such as lesionectomies. However, considering the intrinsic multifactorial epileptogenic nature of LEATs, a tailored surgical approach should be considered to optimize clinical and seizure outcome, especially for lesions located in the temporal lobe.

Image-guided biopsy of intracranial lesions in children, with a small robotic device: a case series.

BACKGROUND AND OBJECTIVES: Robot-assisted biopsies have gained popularity in the last years. Most robotic procedures are performed with a floor-based robotic arm. Recently, Medtronic Stealth Autoguide, a miniaturized robotic arm that work together with an optical neuronavigation system, was launched. Its application in pediatric cases is relatively unexplored. In this study, we retrospectively report our experience using the Stealth Autoguide, for frameless stereotactic biopsies in pediatric patients. METHODS: Pediatric patients who underwent stereotactic biopsy using the Stealth Autoguide cranial robotic platform from July 2020 to May 2023 were included in this study. Clinical, neuroradiological, surgical, and histological data were collected and analyzed. RESULTS: Nineteen patients underwent 20 procedures (mean age was 9-year-old, range 1-17). In four patients, biopsy was part of a more complex surgical procedure (laser interstitial thermal therapy - LITT). The most common indication was diffuse intrinsic brain stem tumor, followed by diffuse supratentorial tumor. Nine procedures were performed in prone position, eight in supine position, and three in lateral position. Facial surface registration was adopted in six procedures, skull-fixed fiducials in 14. The biopsy diagnostic tissue acquisition rate was 100% in the patients who underwent only biopsy, while in the biopsy/LITT group, one case was not diagnostic. No patients developed clinically relevant postoperative complications. CONCLUSION: The Stealth Autoguide system has proven to be safe, diagnostic, and highly accurate in performing stereotactic biopsies for both supratentorial and infratentorial lesions in the pediatric population.

Surgical Approaches to the Third Ventricle: An Update.

The third ventricle is located in the deepest part of the brain and is delimited by both telencephalic and diencephalic structures. Its location makes every surgical procedure inside or around it quite challenging, due to the distance from the surface to the fragility of the neurovascular structures that is necessary to dissect before entering its cavity and to the narrow surgical corridors through which it is necessary to work. Its geometric localization inside the cranial cavity and the anatomical relationship with the interhemispheric fissure offers nevertheless to the surgeon an impressive variety of surgical approaches, which allow to reach every millimeter of the third ventricle lumen. Mastering properly all these approaches requires an impressive anatomical knowledge, the best available technology, and most refined technical skills, making the surgery of the third ventricle a point of excellence in the evolution of each neurosurgeon. The development of neuronavigation and neuroendoscopy has been a revolution in neurosurgery in the last 20 years and offered special advantages for the surgery of the third ventricle. In fact, the narrow corridors of approach make the precision of the neuronavigation and the enlightenment and magnification of the neuroendoscopy especially useful to reach the third ventricle cavity and working inside or around it. This chapter reviews the history of the surgery of the third ventricle and offers an update of the variety of surgical corridors identified and of the technology now available to properly work through them and inside the third ventricle cavity.

Dry Field Technique and Ultrasonic Aspirator in Endoscopic Removal of a Hemorrhagic Intraventricular Tumor in a 2-Year-Old Girl.

Neuroendoscopic procedures inside the ventricular system always bear the risk for an unexpected intraoperative hemorrhage. Most hemorrhages can be managed by constant irrigation with low- and high-pressure washes. In the other rare cases, the dry field technique may be necessary.1-5 It requires the aspiration of the entire intraventricular cerebrospinal fluid with the aim of establishing a proper environment for hemostasis. Video 1 illustrates a step-by-step removal of an intraventricular tumor in a 2-year-old girl through an endoscopic technique where the dry field technique was undertaken because of its hemorrhagic nature. Postoperative magnetic resonance imaging showed complete removal of the left frontal tumor infiltration at the level of the left frontal ependyma. The small residual tumor on the left frontal horn was removed using microsurgical technique with another procedure and after achieving complete removal of all visible tumor, the patient was referred to radiotherapy.

Hemostasis in a giant intraventricular tumor using a saline-cooled radiofrequency bipolar coagulator: technical note.

BACKGROUND: Meningiomas are relatively rare in children and tend to be intraventricular and cystic, with often malignant behavior. Complete excision is associated with the most favorable outcome; moreover, the size and extent of these lesions often make complete excision in one step impossible because of the risk of intraoperative death from uncontrollable hemorrhage. CASE PRESENTATION: A 10-year-old girl was admitted for headache in the last 3 months and was found to have a giant left intraventricular lesion with a volume of 166.63 cm3, which caused hydrocephalus and significant mass effect. Very large draining veins were evident within the tumor, draining into the thalamostriates and internal cerebral veins. Cerebral angiography showed multiple feeders originating mainly from branches of the posterior left choroidal artery with distal afferents that could not be embolized. Therefore, a left parietal transcortical approach was chosen. Given the vascularity of the tumor, saline-cooled radiofrequency coagulation (Aquamantys®) was used to reduce blood loss intraoperatively. Gross total resection (GTR) was achieved with an estimated blood loss of 640 mL. Pathology analysis was consistent with WHO grade 1 transitional meningioma. Postoperatively, the patient was neurologically intact, and MRI confirmed complete resection. CONCLUSION: Aquamantys® is a novel bipolar coagulation device that employs a new bipolar coagulation technique combining radiofrequency energy and saline to achieve hemostatic sealing by denaturing collagen fibers. This offers the possibility of achieving adequate hemostasis even in giant intraventricular tumors in infants to obtain GTR resection with minimal blood loss.

Pure endoscopic ultrasonic removal of choroid plexus papillomas of the third ventricle: technical report of two cases.

BACKGROUND: Tumors of the choroid plexus of the third ventricle are uncommon. Surgical excision is technically challenging because of the rich vascularisation, central location, and high incidence in young children. Open microsurgical resection is considered the standard treatment. However, attempts at purely endoscopic removal of choroid plexus tumors of the third ventricle have also been made in the past, with encouraging results. CASE REPORTS: We report our experience with endoscopic ultrasonic removal of two cases of tumors of the third ventricular choroid plexus. The first case was a large atypical choroid plexus papilloma (WHO grade 2) in the anterior third ventricle associated with hydrocephalus; the second case was a smaller choroid plexus papilloma (WHO grade 1) in the middle/posterior third ventricle without overt hydrocephalus requiring a more anterior neuronavigation guided approach. DISCUSSION AND CONCLUSION: Choroid plexus papillomas of the third ventricle can be safely treated by a purely endoscopic approach because they are usually smaller than their counterparts in the lateral ventricle and often have a recognizable vascular pedicle. Early detection and control of the vascular pedicle at the choroidal border is key to success. The use of ultrasonic aspirator facilitates and expedites endoscopic access. By alternating surface coagulation with fragmentation and aspiration with the ultrasonic aspirator, the tumor can be removed without difficult dissection maneuvers.

Fourth ventricle to spinal subarachnoid space stenting in pediatric patients with refractory syringomyelia: case series and systematic review.

A series of 5 patients treated with the fourth ventricle to spinal subarachnoid space stent (FVSSS) is presented. Indication for surgery, surgical technique, pre-operative and post-operative images, and outcome are analyzed. A systematic review of the pertinent literature has also been performed. This is a retrospective cohort review of a series of 5 consecutive patients with refractory syringomyelia who underwent a fourth ventricle to spinal subarachnoid space shunt surgery. The surgical indication was based on the presence of refractory syringomyelia in patients already treated for Chiari malformation or in patients who developed scarring at the level of the outlets of the fourth ventricle following posterior fossa tumor surgery. The mean age at FVSSS was 11.30 ± 5.88 years. Cerebral MRI revealed crowded posterior fossa, with a membrane at the level of the foramen of Magendie. Spinal MRI showed syringomyelia in all patients. Before surgery, the averages of the craniocaudal and the anteroposterior diameter were 22.66 and 1.01 cm, respectively, whereas the volume was 28.16 cm3. The post-operative period was uneventful in 4 out of 5 patients; one child died on the 1st post-operative day due to complications unrelated to surgery. In remaining cases, syrinx marked improvement. The post-operative volume was 1.47 cm3 with an overall reduction of 97.61%. With regard to literature, 7 articles with a total of 43 patients were analyzed. After FVSSS, syringomyelia reduction was observed in 86.04% of cases. Three patients underwent reoperation due to syrinx recurrence. Four patients presented a catheter displacement, one a wound infection and meningitis and one CSF leak requiring placement of a lumbar drain. FVSSS is highly effective in restoring CSF dynamics, with dramatic improvement of syringomyelia. In all our cases, the volume of the syrinx was reduced by at least 90%, with improvement/resolution of accompanying symptomatology. This procedure should be reserved to patients in which other causes of gradient pressure between the fourth ventricle and subarachnoid space are excluded, for example, tetraventricular hydrocephalus. Surgical procedure is not simple, because it requires meticulous microdissection of cerebello-medullary fissure and upper cervical spine, in already operated patients. To avoid migration of the stent, it should be carefully sutured to the dura mater or thick arachnoid membrane.

Posterior Fossa Laser Interstitial Thermal Therapy in Children.

Real-time, MRI-guided laser interstitial thermal therapy (MRgLITT) is emerging as a minimally invasive technique for epilepsy surgery and for deep-seated tumors in the pediatric population. However, MRgLITT for posterior fossa lesions poses a unique challenge that is especially evident in this age range and remains understudied. In this study, we report our experience and analyze the current literature on MRgLITT for the treatment of posterior fossa in children.

Acute ischemic stroke secondary to ventriculoperitoneal shunt dysfunction in a child with Moyamoya syndrome.

Background: Patients with brain vascular disease and hydrocephalus may be predisposed to acute ischemic stroke in case of shunt dysfunction and subsequent increased intracranial pression. Patients with brain tumor may develop hydrocephalus as a consequence of obstruction of cerebrospinal fluid pathways and radiation-induced moyamoya syndrome secondary (RIMS) to radiotherapy (RT). Case Description: A 15-year-old male patient, affected by hydrocephalus and RIMS, presented acute cerebral ischemia after an episode of shunt malfunction. The shunt was promptly revised and the areas of ischemia visible at magnetic resonance imaging significantly decreased. Conclusion: Children who receive RT for brain tumor, particularly if the circle of Willis region is involved, require close surveillance for the development of vasculopathy and consequent stroke. This surveillance must be even tighter if the patient has been treated with ventricular shunt for the possible synergistic interaction between the two causes on reducing cerebral perfusion and increasing the risk of acute ischemic events.

Mystery(n) Phenotypic Presentation in Europeans: Report of Three Further Novel Missense RNF213 Variants Leading to Severe Syndromic Forms of Moyamoya Angiopathy and Literature Review.

Moyamoya angiopathy (MMA) is a rare cerebral vasculopathy in some cases occurring in children. Incidence is higher in East Asia, where the heterozygous p.Arg4810Lys variant in RNF213 (Mysterin) represents the major susceptibility factor. Rare variants in RNF213 have also been found in European MMA patients with incomplete penetrance and are today a recognized susceptibility factor for other cardiovascular disorders, from extracerebral artery stenosis to hypertension. By whole exome sequencing, we identified three rare and previously unreported missense variants of RNF213 in three children with early onset of bilateral MMA, and subsequently extended clinical and radiological investigations to their carrier relatives. Substitutions all involved highly conserved residues clustered in the C-terminal region of RNF213, mainly in the E3 ligase domain. Probands showed a de novo occurring variant, p.Phe4120Leu (family A), a maternally inherited heterozygous variant, p.Ser4118Cys (family B), and a novel heterozygous variant, p.Glu4867Lys, inherited from the mother, in whom it occurred de novo (family C). Patients from families A and C experienced transient hypertransaminasemia and stenosis of extracerebral arteries. Bilateral MMA was present in the proband's carrier grandfather from family B. The proband from family C and her carrier mother both exhibited annular figurate erythema. Our data confirm that rare heterozygous variants in RNF213 cause MMA in Europeans as well as in East Asian populations, suggesting that substitutions close to positions 4118-4122 and 4867 of RNF213 could lead to a syndromic form of MMA showing elevated aminotransferases and extracerebral vascular involvement, with the possible association of peculiar skin manifestations.

Pediatric Moyamoya Disease and Syndrome in Italy: A Multicenter Cohort.

Background: Moyamoya is a rare progressive cerebral arteriopathy, occurring as an isolated phenomenon (moyamoya disease, MMD) or associated with other conditions (moyamoya syndrome, MMS), responsible for 6-10% of all childhood strokes and transient ischemic attacks (TIAs). Methods: We conducted a retrospective multicenter study on pediatric-onset MMD/MMS in Italy in order to characterize disease presentation, course, management, neuroradiology, and outcome in a European country. Results: A total of 65 patients (34/65 women) with MMD (27/65) or MMS (38/65) were included. About 18% (12/65) of patients were asymptomatic and diagnosed incidentally during investigations performed for an underlying condition (incMMS), whereas 82% (53/65) of patients with MMD or MMS were diagnosed due to the presence of neurological symptoms (symptMMD/MMS). Of these latter, before diagnosis, 66% (43/65) of patients suffered from cerebrovascular events with or without other manifestations (ischemic stroke 42%, 27/65; TIA 32%, 21/65; and no hemorrhagic strokes), 18% (12/65) of them reported headache (in 4/12 headache was not associated with any other manifestation), and 26% (17/65) of them experienced multiple phenotypes (≥2 among: stroke/TIA/seizures/headache/others). Neuroradiology disclosed ≥1 ischemic lesion in 67% (39/58) of patients and posterior circulation involvement in 51% (30/58) of them. About 73% (47/64) of patients underwent surgery, and 69% (45/65) of them received aspirin, but after diagnosis, further stroke events occurred in 20% (12/61) of them, including operated patients (11%, 5/47). Between symptom onset and last follow-up, the overall patient/year incidence of stroke was 10.26% (IC 95% 7.58-13.88%). At last follow-up (median 4 years after diagnosis, range 0.5-15), 43% (26/61) of patients had motor deficits, 31% (19/61) of them had intellectual disability, 13% (8/61) of them had epilepsy, 11% (7/61) of them had behavioral problems, and 25% (13/52) of them had mRS > 2. The proportion of final mRS > 2 was significantly higher in patients with symptMMD/MMS than in patients with incMMS (p = 0.021). Onset age <4 years and stroke before diagnosis were significantly associated with increased risk of intellectual disability (p = 0.0010 and p = 0.0071, respectively) and mRS > 2 at follow-up (p = 0.0106 and p = 0.0009, respectively). Conclusions: Moyamoya is a severe condition that may affect young children and frequently cause cerebrovascular events throughout the disease course, but may also manifest with multiple and non-cerebrovascular clinical phenotypes including headache (isolated or associated with other manifestations), seizures, and movement disorder. Younger onset age and stroke before diagnosis may associate with increased risk of worse outcome (final mRS > 2).

Herophilus-Galen line as a predictor of extent of resection in the occipital interhemispheric transtentorial approach to pineal tumors in children.

OBJECTIVE: The goals of this study were to evaluate the extent of resection (EOR) obtained with an occipital interhemispheric transtentorial approach (OITA) in a series of pediatric patients with pineal region tumors and to define preoperative radiological factors predictive of the EOR. METHODS: This is a retrospective cohort study of a series of pediatric patients with pineal tumors who underwent surgery through a microsurgical OITA performed by the senior author during the period from January 2006 to January 2020. The tumor volume was measured preoperatively, and then on sagittal midline cuts the authors identified the most cranial point of the torcular Herophili (defined as the "Herophilus point") and the lowest point of the inferior profile of the vein of Galen (defined as the "Galen point"). The line joining these two points (defined as the "Herophilus-Galen line" [H-G line]) was used to identify the "Herophilus-Galen plane" (H-G plane) perpendicular to the sagittal plane. Tumor volumes located below and above this plane were measured. EOR was evaluated by measuring residual tumor volume visible on T1 volumetric injected sequences of immediate postoperative MRI. RESULTS: Thirty patients were selected for study inclusion. The preoperative mean tumor volume was 15.120 cm3 (range 0.129-104.3 cm3). The mean volumes were 2.717 cm3 (range 0-31 cm3) above the H-G plane and 12.40 cm3 (median 5.27 cm3, range 0.12-72.87 cm3) below the H-G plane. Three patients underwent only biopsy. Of the remaining 27 patients, gross-total resection (GTR; 100% tumor volume) was achieved in 20 patients (74%). In the remaining 7 patients, the mean residual tumor volume was 7.3 cm3 (range 0.26-17.88 cm3). In 3 of these patients, GTR was accomplished after further surgical procedures (1 in 2 patients, 3 in 1 patient) for an overall GTR rate of 85.18%. Larger tumor volume was significantly associated with incomplete resection (p < 0.001). A tumor volume ≤ 2 cm3 above the H-G plane (p = 0.003), linear extension ≤ 1 mm above the H-G line, and pineal histology were predictive of GTR at first OITA procedure (p = 0.001). CONCLUSIONS: The H-G line is an intuitive, easy-to-use, and reliable indicator of the superior anatomical limit of visibility during the microsurgical OITA. This anatomical landmark may be useful as a predictor of EOR for pineal tumors performed through this approach. The main limitations of this study are the small number of patients and the exclusively pediatric age of the patient population.

Posterior Fossa Tumours in the First Year of Life: A Two-Centre Retrospective Study.

Posterior fossa tumours (PFTs) in infants are very rare, and information on these tumours is scarce in the literature. This retrospective study reports their pathological characteristics and describes surgical aspects and treatment outcomes. A two-centre cohort of infants with PFTs treated from 2007 to 2018 was retrospectively reviewed. Patient characteristics, clinical, and treatment data were reviewed. Survival curves for progression-free survival (PFS) and overall survival (OS) were generated. Thirty-three infants were retrieved. There were 11 low grade and 22 high-grade tumours. The most common presenting symptom was intracranial hypertension. Fifteen children out of thirty-three progressed. Five-year PFS was significantly lower in children with high-grade tumours (38.3%) than those with low-grade tumours (69.3%), p = 0.030. High-grade pathology was the only predictor of progression (HR 3.7, 95% CI 1.1-13.31), p = 0.045. Fourteen children with high-grade tumours died, with a 5-year OS of 55.25%. PFTs in children below one year of age still represent a unique challenge. Infants with high-grade tumours display the worst outcomes and the lowest survival, indicating that more effective strategies are needed.

The Clinical and Prognostic Impact of the Choice of Surgical Approach to Fourth Ventricular Tumors in a Single-Center, Single-Surgeon Cohort of 92 Consecutive Pediatric Patients.

Objective: A single-institution cohort of 92 consecutive pediatric patients harboring tumors involving the fourth ventricle, surgically treated via the telovelar or transvermian approach, was retrospectively reviewed in order to analyze the impact of surgical route on surgery-related outcomes and cumulative survival. Methods: Clinical, radiological, surgical, and pathology details were retrospectively analyzed. We selected n = 6 surgery-related clinical and radiological outcomes: transient and permanent neurological deficits, duration of assisted ventilation, postoperative new onset medical events, postoperative cerebellar mutism, and extent of resection. We built univariate and multivariate logistic models to analyze the significance of relationships between the surgical routes and the outcomes. Cumulative survival (CS) was estimated by the cohort approach. Results: There were 53 girls and 39 boys (mean age, 83 months). Telovelar approach was performed in 51 cases and transvermian approach in 41 cases. Early postoperative MRI studies showed complete removal in 57 cases (62%) and measurable residual tumor in 35 cases (38%). The average tumor residual volume was 1,316 cm3 (range, 0.016-4.231 cm3; median value, 0.9875 cm3). Residual disease was more often detected on immediate postop MRI after telovelar approach, but the difference was not significant. Cerebellar mutism was observed in 10 cases (11%). No significant difference in the onset of cerebellar mutism was detected between telovelar and transvermian approach. The choice of surgical approach did not significantly modify any other postoperative outcome and 1-/3-year CS of high-grade surgically treated tumors. Conclusions: With the limitation of a single-center, single-surgeon retrospective series, our findings offer significant data to reconsider the real impact of the choice of the surgical route to the fourth ventricle on the incidence of cerebellar mutism and surgery-related morbidity. This seems to be in line with some recent reports in the literature. Surgical approach to the fourth ventricle should be individualized according to the location of the tumor, degree of vermian infiltration, and lateral and upward extension. Telovelar and transvermian approaches should not be considered alternative but complementary. Pediatric neurosurgeons should fully master both approaches and choose the one that they consider the best for the patient based on a thorough and careful evaluation of pre-operative imaging.

Neuroendoscopic treatment of symptomatic cyst of the septum pellucidum in children: A case series.

BACKGROUND: Symptomatic cysts of the septum pellucidum (CSP) are extremely rare in children and surgical indications are not well defined. A very careful clinical and neuroradiologic evaluation is necessary to consider a patient for surgical indication. METHODS: We present a surgical series of 7 pediatric patients. Clinical and radiological features of the patients, including clinical presentation, previous treatment, pre, and post-operative MRI, immediate postoperative, neuropsychiatric assessment, and outcomes were reviewed. RESULTS: There were 5 males and 2 females (mean age 8 yrs). Five patients presented a history of severe intermittent headaches, two of them were admitted with acute symptoms of raised intracranial pressure. One patient presented Epilepsy and ADHD and one patient had severe psychosis. Overall, psychiatric disorders were diagnosed in six patients, three patients had Intellectual Disability (ID). In all cases, the cyst presented a ballooning feature, with a mean volume of 18,36 cm3 (range 10,62-28,5) and significant lateral bulging of both layers. All were operated on endoscopically without complications. After surgery, a very significant decrease in cyst volume was observed (mean volume 5,68 cm3; range 3,18-10,1) with complete disappearance of the ballooning aspect. Headaches resolved in all patients. In two patients operated in emergency papilloedema and vision improved in the first week after surgery. No recurrence of the cysts was noted during follow-up in all patients. CONCLUSIONS: CSP may be associated with behavioral or psychiatric problems also in children. Neuroendoscopic surgery is a safe and effective therapeutic modality to treat CSP presenting with symptoms and signs of intracranial hypertension with good clinical results.

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.

Occipital interhemispheric transtentorial approach to a pineoblastoma in a 4-year-old child.

The authors present a pediatric case of a pineoblastoma treated with gross-total removal through an occipital interhemispheric transtentorial approach (OITA). The child presented with acute hydrocephalus that was treated by endoscopic third ventriculostomy (ETV) and tumor biopsy through a single burr hole. Histology revealed a pineoblastoma. Microsurgical total removal was performed 3 months after neoadjuvant chemotherapy. OITA was chosen on the basis of the tumor's location below the Herophilus-Galen line of sight. In this video, the authors show the positioning, the operating devices, the approach, and the microsurgical dissection, indicating all the neurovascular structures encountered. The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2122.

Interhemispheric transcallosal transchoroidal approach to a pineal teratoma in a 15-year-old boy.

In this video, the authors present an interhemispheric transcallosal transchoroidal approach to a pineal mass in a 15-year-old boy. He received emergency endoscopic third ventriculostomy (ETV), then an endoscopic biopsy that revealed an immature teratoma. Surgical removal was selected. The mass was located very high in the posterior third ventricle, hidden behind the splenium of the corpus callosum and the vein of Galen, so an interhemispheric transcallosal approach followed by a complete dissection of the whole choroidal fissure was chosen and allowed complete removal of the tumor. Microsurgical dissection is presented, showing clearly in detail all the neurovascular structures encountered. The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2126.