Mother-Daughter Ventricular Endoscopy: A Technical Note and 2-Dimensional Video.

BACKGROUND AND IMPORTANCE: While navigating the ventricles with a rigid endoscope provides excellent visualization and the ability to use endoscopic instruments for complex surgery, these endoscopes are often too large to navigate tight areas. We present a surgical video showing the technique of mother-daughter endoscopy, which consists of the introduction of a flexible 1-mm fiberoptic endoscope through the channel of a large rigid endoscope to allow visualization across small spaces or channels, in this case, the cerebral aqueduct. This combination of superior visualization and handling of rigid endoscopes and flexibility and small size of fiberoptic endoscopes enhances safety and broadens possibilities in ventricular surgery. CLINICAL PRESENTATION: A 64-year-old woman with prior endoscopic aqueductoplasty for triventricular hydrocephalus and a failed endoscopic third ventriculostomy presented with focal restenosis of the aqueduct. A repeat endoscopic aqueductoplasty with stent placement were performed. Mother-daughter endoscopy was used to explore the occluded aqueduct for improved safety before fenestration and to ensure proper stent placement after fenestration. CONCLUSION: Mother-daughter endoscopy can add safety to complex or high-risk endoscopic procedures, particularly those with tight spaces that the large mother endoscope cannot visualize.

A rare case of intralesional haemorrhage of a benign aqueductal cyst after CSF diversion treatment. A case report and review of literature.

Benign cysts within the pure aqueductal region are a rare entity. Their critical location within the ventricular system presents a risk of potentially catastrophic outcomes. We present a case of a 68-year-old female who was transferred to our unit with an acute obstructive triventricular hydrocephalus caused by a benign cyst within the cerebral aqueduct. She became unconscious and had an urgent endoscopic third ventriculostomy (ETV). Post-operatively, the patient was recovering well but then developed a sudden onset severe headache accompanied by vomiting. Imaging revealed intracystic haemorrhage with expansion of lesion but there was no obstructive hydrocephalus due to CSF diversion performed 9 d prior. She was treated conservatively and continued to improve.

Comparative anatomy of dissected optic lobes, optic ventricles, midbrain tectum, collicular ventricles, and aqueduct: evolutionary modifications as potential explanation for non-tumoral aqueductal anomalies in humans.

PURPOSE: An extensive literature has postulated multiple etiologies for aqueductal stenosis. No publications were found, discussing that evolutionary modifications might explain aqueductal anomalies. This study's objectives were to review the evolutionary modifications of vertebrates' tectum structures that might explain human aqueduct anomalies. Undertaking vertebrate comparative study is currently not feasible in view of limitations in obtaining vertebrate material. Thus, vertebrate material collected, injected, dissected, and radiographed in the early 1970s was analyzed, focusing on the aqueduct and components of the midbrain tectum. METHODS: Photographs of brain dissections and radiographs of the cerebral ventricles and arteries of adult shark, frog, iguana, rabbit, cat, dog, and primate specimens, containing a barium-gelatin radiopaque compound, were analyzed focusing on the aqueduct, the optic ventricles, the quadrigeminal plate, and collicular ventricles. The anatomic information provided by the dissections and radiographs is not reproducible by any other radiopaque contrast currently available. RESULTS: Dissected and radiographed cerebral ventricular and arterial systems of the vertebrates demonstrated midbrain tectum changes, including relative size modifications of the mammalian components of the tectum, simultaneously with the enlargement of the occipital lobe. There is a transformation of pre-mammalian optic ventricles to what appear to be collicular ventricles in mammals, as the aqueduct and collicular ventricle form a continuous cavity. CONCLUSIONS: The mammalian tectum undergoes an evolutionary cephalization process consisting of relative size changes of the midbrain tectum structures. This is associated with enlargement of the occipital lobe, as part of overall neocortical expansion. Potentially, aqueductal anomalies could be explained by evolutionary modifications.

Unilateral Tension Pneumocephalus of the Sylvian Fissure: A Rare Neurosurgical Complication.

Tension pneumocephalus is an uncommon complication of neurosurgical procedures. We report a patient who presented with headache, vomiting, left hemiparesis and rhinorrhea 30 days after correction of a recurrent nasal cerebrospinal fluid fistula and shunt placement. A computed tomography scan revealed a massive collection of air with air-fluid level in the right sylvian fissure and midline shift. A right pterional craniotomy was performed and a small corticectomy resulted in evacuation of air from the sylvian fissure. A dural graft from the previous surgery was recognized to be acting as a ball-valve mechanism, trapping air from the nasal cavity. It was removed and the cranial defect was corrected with a split calvarial bone graft. Follow-up brain computed tomography revealed complete resolution of pneumocephalus. After surgery there was progressive improvement of neurological symptoms over 10 days, and the patient was asymptomatic after 1 month of follow-up.

Progressive midbrain clefts after head trauma and decompressive surgery: a report of two patients.

This report describes two patients with acute-onset ptosis, oculomotor dysfunction, ataxia and drowsiness, referable to the midbrain tegmentum. Both patients had previously suffered severe closed head injuries requiring craniotomy for cerebral decompression. Serial brain scans in both cases revealed a newly developing cleft in the midbrain, with features suggestive of abnormal cerebrospinal fluid (CSF) flow across the aqueduct. A trial of acetazolamide was initiated to reduce CSF production, followed by a third ventriculostomy for CSF diversion in one patient, which resulted in arrested disease progression and partial recovery. There are only two previous reports in the literature of midbrain clefts that developed as remote sequelae of head trauma. We postulate that altered CSF flow dynamics in the aqueduct, possibly related to changes in brain compliance, may be contributory. Early recognition and treatment may prevent irreversible structural injury and possible death.

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.

Relationship between pineal cyst size and aqueductal CSF flow measured by phase contrast MRI.

BACKGROUND: Most patients with pineal cysts referred for neurosurgical consultation have no specific symptoms or objective findings except for pineal cyst size to help in management decisions. Our purpose was to assess the relationship between pineal cyst size and aqueductal CSF flow using PC-MRI. METHODS: Eleven adult patients with pineal cysts (>1 cm) referred for neurosurgical consultations were included. Cyst volume was calculated using 3D T1 images. Phase contrast magnetic resonance imaging (PC-MRI) in axial plane with velocity encoding of 5 cm/sec was used to quantitatively assess CSF flow through the cerebral aqueduct to determine the aqueductal stroke volume, which was then correlated to cyst size using Pearson's correlation. Pineal cysts were grouped by size into small (6/11) and large (5/11) using the median value to compare aqueductal stroke volume using Mann-Whitney test. RESULTS: Patients were 39±13 years (mean±SD) of age, and 10/11 (91%) were female. There was significant negative correlation between cyst volume and aqueductal stroke volume (r=0.74; P=0.009). Volume of small cysts (4954±2157 mm3) was significantly different compared to large cysts (13,752±3738 mm3; P=0.008). The aqueductal stroke volume of patients harboring large cysts 33±8 µL/cardiac cycle was significantly lower than that of patients with small cysts 96±29 µL/cardiac cycle (P=0.008). CONCLUSIONS: Aqueductal CSF flow appears to decrease with increasing pineal cyst size. Our preliminary results provide first evidence that even in the absence of objective neurological findings or hydrocephalus; larger pineal cysts already display decreased CSF flow through the cerebral aqueduct.

Microstructural Injury to Left-Sided Perisylvian White Matter Predicts Language Decline After Brain Radiation Therapy.

PURPOSE: Our purpose was to investigate the association between imaging biomarkers of radiation-induced white matter (WM) injury within perisylvian regions and longitudinal language decline in patients with brain tumors. METHODS AND MATERIALS: Patients with primary brain tumors (n = 44) on a prospective trial underwent brain magnetic resonance imaging, diffusion-weighted imaging, and language assessments of naming (Boston Naming Test [BNT]) and fluency (Delis-Kaplan Executive Function System Category Fluency [DKEFS-CF]) at baseline and 3, 6, and 12 months after fractionated radiation therapy (RT). Reliable change indices of language function (0-6 months), accounting for practice effects (RCI-PE), evaluated decline. Bilateral perisylvian WM regions (superficial WM subadjacent to Broca's area and the superior temporal gyrus [STG], inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus [IFOF], and arcuate fasciculus) were autosegmented. We quantified volume and diffusion measures of WM microstructure: fractional anisotropy (FA; lower values indicate disruption) and mean diffusivity (MD; higher values indicate injury). Linear mixed-effects models assessed mean dose as predictor of imaging biomarker change and imaging biomarkers as longitudinal predictors of language scores. RESULTS: DKEFS-CF scores declined at 6 months post-RT (RCI-PE, -0.483; P = .01), whereas BNT scores improved (RCI-PE, 0.262; P = .04). Higher mean dose to left and right regions was predictive of decreased volume (left-STG, P = .02; right-ILF and IFOF, P = .03), decreased FA (left-WM tracts, all P < .01; right-STG and IFOF, P < .02), and increased MD of left-WM tracts (all P < .03). Volume loss within left-Broca's area (P = .01), left-ILF (P = .01), left-IFOF (P = .01), and left-arcuate fasciculus (P = .04) was associated with lower BNT scores. Lower FA correlated with poorer DKEFS-CF and BNT scores within left-ILF (P = .02, not significant), left-IFOF (P = .02, .04), and left-arcuate fasciculus (P = .01, .01), respectively. Poorer DKEFS-CF scores correlated with increased MD values within the left-arcuate fasciculus (P = .03). Right-sided biomarkers did not correlate with language scores. CONCLUSIONS: Patients with primary brain tumors experience language fluency decline post-RT. Poorer fluency and naming function may be explained by microstructural injury to left-sided perisylvian WM, representing potential dose-avoidance targets for language preservation.

Central neurocytoma originating in third ventricle with expansion into the cerebral aqueduct and fourth ventricle: Case report and review of literature.

BACKGROUND: Central Neurocytomas (CNs) are rare brain tumors, making up less than 1% of all primary tumors within the CNS. They are commonly located in the lateral ventricles, and often present with visual changes and symptoms of obstructive hydrocephalus. Histopathology shows characteristics similar to ependymomas and oligodendrogliomas, however tumor cells display neuronal differentiation, and immunohistochemical stains typically for synaptophysin. Gross total resection is the most important prognostic indicator of survival. CASE DESCRIPTION: We describe the case of a 48-year-old male with a CN originating in the third ventricle with expansion through the cerebral aqueduct into the fourth ventricle. He presented with bi-frontal headaches, imaging revealed an avidly enhancing tumor occupying the inferior third ventricle, cerebral aqueduct, with expansion into the fourth ventricle. An interhemispheric craniotomy with a transcallosal transchoroidal approach to the third ventricle was performed, this provided a trajectory that paralleled the long axis of the tumor. Postoperative imaging confirmed a near total resection with linear residual enhancement on the anterior wall of the fourth ventricle. Intensity modulated radiotherapy was performed, 7-month follow-up imaging was clean. CONCLUSION: CNs are rare brain tumors, most commonly located within the lateral ventricles. We describe a rare case of a CN spanning from the third ventricle into the cerebral aqueduct and fourth ventricle. To our knowledge, this is only the fourth reported case of such a tumor. Surgical approach must be carefully selected, as gross total resection is the most important prognostic indicator.

Biventricular hydrocephalus secondary to aqueductal developmental venous anomaly.

Developmental venous anomaly (DVA) is the most common type of intracranial vascular malformation. These lesions are benign and are considered to be non-pathological variants of normal deep parenchymal veins. Although most of them are asymptomatic, a small subset of them located in aqueductal region have been reported to cause obstructive hydrocephalus. The authors present an interesting case of biventricular hydrocephalus secondary to a DVA located on the proximal aqueduct in an adolescent patient. This case is discussed with in corroboration with current literature and management recommendations.

A retrospective regional study of aqueduct stenosis and fourth ventricle outflow obstruction in the paediatric complex neurofibromatosis type 1 population; Aetiology, clinical presentation and management.

OBJECTIVES: Aqueduct stenosis (AS) and fourth ventricle outflow obstruction are rare associations of neurofibromatosis type 1 (NF1), resulting in ventriculomegaly and hydrocephalus requiring surgical treatment. This study aims to identify the prevalence of AS and its patterns of clinical presentation, aetiology and treatment in the paediatric complex NF1 population. PATIENTS AND METHODS: Patients with NF-1 aged 0-18 years were recruited from the Regional Genetic Family Register, following institutional review board approval. Magnetic resonance imaging data and clinical documents were reviewed with respect to clinical presentation, degree of ventriculomegaly, aetiological factors and management of AS and fourth ventricle outflow obstruction. RESULTS: 24 of the 233 paediatric patients seen within the NHS highly specialised service for complex NF1 were found to have AS or and fourth ventricle outflow obstruction. This included 13 males and 11 females with a mean age of 9 years 5 months (range 8 months - 17 years). The majority of patients with AS or fourth ventricle outflow obstruction presented with symptoms of raised intracranial pressure associated with ventriculomegaly and/or hydrocephalus (n = 18). However, in 25 % of patients, AS was an incidental finding on MRI and was observed both in the presence (n = 2) and absence (n = 4) of ventriculomegaly. In the majority of cases a single cause of AS was identified (n = 16), of which tectal plate thickening (n = 7) was most frequently observed. The remaining 8 patients had multiple causes of AS, in which tectal plate thickening (n = 7) and aqueductal webs (n = 5) were the most common observations. Surgery was performed on all patients with evidence of raised pressure (n = 8) by performing endoscopic third ventriculostomy (ETV) (n = 5) or ventriculoperitoneal (VP)-shunting (n = 3). Tectal plate thickening was most frequently observed in patients who underwent ETV (n = 3), followed by aqueductal web (n = 1) and T2-signal changes in the tectal plate (n = 1). Patients treated with VP-shunt had 4th ventricle outflow obstruction (n = 2) and a tectal plate tumour (n = 1). CONCLUSION: This study identifies that AS is more prevalent amongst the paediatric complex NF-1 population than previously reported, occurring in 10 % of cases. Our findings demonstrate that AS is most commonly symptomatic in presentation but can be asymptomatic in 25 % of paediatric complex NF1 patients. In this population, AS can occur both in the presence and absence of ventriculomegaly and therefore requires careful monitoring for development of hydrocephalus. In this study, over one third of patients (9 of 24 patients) with AS eventually required treatment.

A case of developing obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies.

Developmental venous anomalies (DVAs), previously also known as venous angiomas, are variations of normal trans-medullary veins draining from white and gray matter. DVAs are usually asymptomatic and mostly discovered incidentally on brain imaging. However, some studies have reported symptomatic cases associated with DVAs. In this report, we report an extremely rare case of a 14-month-old boy with obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies. At the age of 14 months, his head circumference exceeded + 2SD significantly. Brain magnetic resonance imaging (MRI) showed triventriculomegaly and dilated collector vein coursing through the Sylvian aqueduct, causing aqueductal stenosis. Endoscopic third ventriculostomy (ETV) was successfully performed. During the procedure, a dilated collector vein was confirmed obstructing the Sylvian aqueduct. Postoperative cine MRI showed good flow signal through the opening and improvement of hydrocephalus was noted. Obstructive hydrocephalus following aqueductal stenosis caused by DVAs is very rare; nonetheless, it can be considered as a causal differential diagnosis for hydrocephalus. Whether ETV should be chosen, as the technique for diversion of cerebrospinal fluid (CSF) flow, remains controversial. This case report showed that ETV was effective and safe.

Surgical Techniques and Long-Term Outcomes of Flexible Neuroendoscopic Aqueductoplasty and Stenting in Infants with Obstructive Hydrocephalus: A Single-Center Study.

OBJECTIVE: To technically review and explore long-term follow-up results of aqueductoplasty and stenting under flexible neuroendoscopy in infantile obstructive hydrocephalus. METHODS: The clinical data, surgical techniques, and long-term effects in 14 infants with obstructive hydrocephalus treated by flexible neuroendoscopic aqueductoplasty and stenting between 2008 and 2010 were analyzed retrospectively. RESULTS: The 14 infants had a mean age of 5.71 ± 3.10 months (range, 2-11 months) and a mean duration of follow-up of 62.64 ± 34.52 months (range, 9-121 months). Subdural effusion was observed in 4 infants (28.6%) after surgery. There were no deaths or serious complications related to intracranial stent placement. Three infants (21.4%) failed, 2 due to proximal aqueduct occlusion from a short stent length and 1 due to intraluminal ependymal adhesion obstruction. One case was abandoned when a second surgical adjustment stent was unsuccessful, and the other 2 cases went to shunt surgery. CONCLUSIONS: Aqueductoplasty with stenting is a feasible and safe surgical procedure for treating infants with midbrain aqueduct stenosis or occlusion. However, the optimal stent material and definitive outcomes after this procedure require additional long-term follow-up studies in large numbers of infants.

Reversible Severe Brainstem Herniation and Obstructive Hydrocephalus from Cystoperitoneal Shunt Overdrainage.

We present a case of symptomatic intracranial hypotension secondary to CSF overdrainage from a cystoperitoneal shunt system. Brain MRI shows distortion of the midbrain with secondary occlusion of the cerebral aqueduct resulting in obstructive hydrocephalus. The symptoms, brainstem herniation, and hydrocephalus resolved after tie occlusion of the shunt.

Hemangioblastoma of Cerebral Aqueduct Removed via Sitting, Supracerebellar Intracollicular Approach.

BACKGROUND: Tumors protruding into the cerebral aqueduct are rare, and tumors arising from within the cerebral aqueduct are rarer still. CASE DESCRIPTION: In this report, we discuss the presentation and clinical outcome of a 65-year-old man who presented to us with symptoms of hydrocephalus. Prior imaging had revealed a small enhancing nodule within the cerebral aqueduct. In the 6 months between initial imaging and our seeing the patient, the tumor demonstrated substantial interval growth, so the patient was offered resection. The tumor was accessed using a sitting, supracerebellar, intracollicular approach, which allowed for gross total resection of the mass without complication. Histopathology later revealed the lesion to be a hemangioblastoma. Two years after surgery, the patient was doing well with no neurologic deficits. CONCLUSIONS: We report the first case of an aqueductal hemangioblastoma and describe our use of a sitting, supracerebellar, intracollicular approach to access tumors occupying this cerebrospinal fluid space.

Brain and cord imaging features in neuromyelitis optica spectrum disorders.

OBJECTIVES: To validate imaging features able to discriminate neuromyelitis optica spectrum disorders from multiple sclerosis with conventional magnetic resonance imaging (MRI). METHODS: In this cross-sectional study, brain and spinal cord scans were evaluated from 116 neuromyelitis optica spectrum disorder patients (98 seropositive and 18 seronegative) in chronic disease phase and 65 age-, sex-, and disease duration-matched multiple sclerosis patients. To identify independent predictors of neuromyelitis optica diagnosis, after assessing the prevalence of typical/atypical findings, the original cohort was 2:1 randomized in a training sample (where a multivariate logistic regression analysis was run) and a validation sample (where the performance of the selected variables was tested and validated). RESULTS: Typical brain lesions occurred in 50.9% of neuromyelitis optica patients (18.1% brainstem periventricular/periaqueductal, 32.7% periependymal along lateral ventricles, 3.4% large hemispheric, 6.0% diencephalic, 4.3% corticospinal tract), 72.2% had spinal cord lesions (46.3% long transverse myelitis, 36.1% short transverse myelitis), 37.1% satisfied 2010 McDonald criteria, and none had cortical lesions. Fulfillment of at least 2 of 5 of absence of juxtacortical/cortical lesions, absence of periventricular lesions, absence of Dawson fingers, presence of long transverse myelitis, and presence of periependymal lesions along lateral ventricles discriminated neuromyelitis optica patients in both training (sensitivity = 0.92, 95% confidence interval [CI] = 0.84-0.97; specificity = 0.91, 95% CI = 0.78-0.97) and validation samples (sensitivity = 0.82, 95% CI = 0.66-0.92; specificity = 0.91, 95% CI = 0.71-0.99). MRI findings and criteria performance were similar irrespective of serostatus. INTERPRETATION: Although up to 50% of neuromyelitis optica patients have no typical lesions and a relatively high percentage of them satisfy multiple sclerosis criteria, several easily applicable imaging features can help to distinguish neuromyelitis optica from multiple sclerosis. ANN NEUROL 2019;85:371-384.