Endoscopic Transforaminal Transchoroidal Approach to the Third Ventricle for Cystic and Solid Tumors.

BACKGROUND: Endoscopic access to the third ventricle is limited by the confinements of the foramen of Monro and can be aided by opening of the choroidal fissure. OBJECTIVE: We describe the endoscopic transforaminal transchoroidal (ETTC) approach to the third ventricle with opening of the choroidal fissure to enlarge the posterior foramen of Monro for treatment of various third ventricular diseases. METHODS: We completed a retrospective review of a prospectively collected database at 3 tertiary academic facilities. The search included patients who underwent endoscopic transcranial procedures between 2005 and 2018. All 13 patients included in this study were treated using the ETTC approach for lesions in the third ventricle using a rigid 6-mm working endoscope. RESULTS: There were 7 women and 6 men with a mean age of 44 years (standard deviation, 16 years). Third ventricular diseases included colloid cyst, craniopharyngioma, anaplastic astrocytoma, subependymal giant cell astrocytoma, metastatic lung adenocarcinoma, and lymphoma. Resection was complete in 7 patients and near complete in 4. Two patients had biopsy of a thalamic tumor and third ventriculostomy. The mean follow-up time was 44 months (standard deviation, 36 months; range, 9-121 months). There were no intraoperative or postoperative complications related to the approach. CONCLUSIONS: ETTC approach is a safe and effective method for enlargement of the foramen of Monro. The approach improves maneuverability of the endoscope and allows a broad range of movement and increased angulation within the foramen of Monro. Attention to anatomy is paramount to avoid injury to the venous structures and fornix.

Near-Infrared Confocal Laser Reflectance Cytoarchitectural Imaging of the Substantia Nigra and Cerebellum in the Fresh Human Cadaver.

BACKGROUND: Cytoarchitectural neuroimaging remains critical for diagnosis of many brain diseases. Fluorescent dye-enhanced, near-infrared confocal in situ cellular imaging of the brain has been reported. However, impermeability of the blood-brain barrier to most fluorescent dyes limits clinical utility of this modality. The differential degree of reflectance from brain tissue with unenhanced near-infrared imaging may represent an alternative technique for in situ cytoarchitectural neuroimaging. METHODS: We assessed the utility of unenhanced near-infrared confocal laser reflectance imaging of the cytoarchitecture of the cerebellum and substantia nigra in 2 fresh human cadaver brains using a confocal near-infrared laser probe. Cellular images based on near-infrared differential reflectance were captured at depths of 20-180 µm from the brain surface. Parts of the cerebellum and substantia nigra imaged using the probe were subsequently excised and stained with hematoxylin and eosin for histologic correlation. RESULTS: Near-infrared reflectance imaging revealed the 3-layered cytoarchitecture of the cerebellum, with Purkinje cells appearing hyperreflectant. In the substantia nigra, neurons appeared hyporeflectant with hyperreflectant neuromelanin cytoplasmic inclusions. Cytoarchitecture of the cerebellum and substantia nigra revealed on near-infrared imaging closely correlated with the histology on hematoxylin-eosin staining. CONCLUSIONS: We showed that unenhanced near-infrared reflectance imaging of fresh human cadaver brain can reliably identify and distinguish neurons and detailed cytoarchitecture of the cerebellum and substantia nigra.

Endoscopic Third Ventriculostomy in 250 Adults With Hydrocephalus: Patient Selection, Outcomes, and Complications.

BACKGROUND: Endoscopic third ventriculostomy (ETV) has been used predominantly in the pediatric population in the past. Application in the adult population has been less extensive, even in large neurosurgical centers. To our knowledge, this report is one of the largest adult ETV series reported and has the consistency of being performed at 1 center. OBJECTIVE: To determine the efficacy, safety, and outcome of ETV in a large adult hydrocephalus patient series at a single neurosurgical center. In addition, to analyze patient selection criteria and clinical subgroups (including those with ventriculoperitoneal shunt [VPS] malfunction or obstruction and neurointensive care unit patients with extended ventricular drainage before ETV) to optimize surgical results in the future. METHODS: We conducted a retrospective review of adult ETV procedures performed at our center between 2000 and 2014. RESULTS: The overall rate of success (no further cerebrospinal fluid diversion procedure performed plus clinical improvement) of 243 completed ETVs was 72.8%. Following is the number of procedures with the success rate in parentheses: aqueduct stenosis, 56 (91%); communicating hydrocephalus including normal pressure hydrocephalus, nonnormal pressure hydrocephalus, and remote head trauma, 57 (43.8%); communicating hydrocephalus in postoperative posterior fossa tumor without residual tumor, 14 (85.7%); communicating hydrocephalus in subarachnoid hemorrhage without intraventricular hemorrhage, 23 (69.6%); obstruction from tumor/cyst, 42 (85.7%); VPS obstruction (diagnosis unknown), 23 (65.2%); intraventricular hemorrhage, 20 (90%); and miscellaneous (obstructive), 8 (50%). There were 9 complications in 250 intended procedures (3.6%); 5 (2%) were serious. CONCLUSION: Use of ETV in adult hydrocephalus has broad application with a low complication rate and reasonably good efficacy in selected patients.

Transciliary supraorbital approach (eyebrow approach) for resection of retrochiasmatic craniopharyngiomas: an alternative approach, case series, and literature review.

INTRODUCTION: Craniopharyngiomas are known for an irregular growth pattern and extension into the retrochiasmatic space with adherence to adjacent structures. We describe the use of the transciliary supraorbital approach (eyebrow approach) for resection of craniopharyngiomas with retrochiasmatic extension. METHODS: Our clinical database was reviewed to identify operative cases of craniopharyngiomas between July 1998 and January 2011. Only patients who had retrochiasmatic extension and underwent an eyebrow approach were included in this analysis. Endoscopy was used to aid surgical resection at the discretion of the surgeon. Six patients were identified (three from a retrospective review and three during the course of prospective follow-up evaluation). RESULTS: The group included three men and three women (mean age: 41.2 years; range: 28-57 years). All patients had visual and hormonal deficits at presentation. Complete resection was achieved in four patients. Endoscopic assistance was used in three patients. Opening of the frontal sinus occurred in two cases during surgery; an additional surgical procedure was required for repair of a cerebrospinal fluid leak in one of these cases. The duration of clinical follow-up ranged from 18 to 97 months. All patients had excellent cosmetic results, visual improvement to a serviceable level, and a Karnofsky performance scale score ≥ 80. CONCLUSIONS: The eyebrow approach is safe for resection of craniopharyngiomas with retrochiasmatic extension. This approach offers a reasonable surgical corridor for resection of the retrochiasmatic tumor component and can be enhanced using endoscopic assistance.

An episode of severely suppressed electrocerebral activity recorded by electroencephalography during endoscopic resection of a colloid cyst.

Intraoperative neuromonitoring utilizing electroencephalography (EEG) is rarely performed during neuroendoscopy. The authors present a case in which this monitoring modality was used for a patient with a colloid cyst in preparation for an open craniotomy should an endoscopic approach fail. In this case, EEG serendipitously captured near-complete cessation of electrocerebral activity that occurred during intraventricular irrigation in response to ventricular collapse and resulted in no postoperative deficits. To the authors' knowledge, this is the first reported case of severe suppression of electrical activity captured by EEG during neuroendoscopy. Although they describe a transient phenomenon that resulted in no residual cognitive or neurological deficits, the importance of cautious introduction of ventricular irrigation, the need to carefully monitor intracranial pressure during neuroendoscopic procedures, and the need to pay close attention to irrigation temperature and composition should not be underestimated. Additional studies regarding the utility of EEG in alerting neurosurgeons to adverse electrical cerebral activity during neuroendoscopy are warranted.

Endoscopic third ventriculostomy for hydrocephalus after perimesencephalic subarachnoid hemorrhage: initial experience in three patients.

BACKGROUND: To review the outcome after endoscopic third ventriculostomy (ETV) for symptomatic, persistent hydrocephalus in three patients with perimesencephalic angiographically negative subarachnoid hemorrhage (PNH) who were dependent on an external ventricular drain (EVD). METHODS: All patients initially presented with severe headache, nuchal rigidity, confusion and lethargy (Hunt-Hess Grade II or III), and persistent, EVD-dependent hydrocephalus. Cranial CT images in each revealed acute hydrocephalus and perimesencephalic hemorrhage pattern with a heavy clot burden (Fisher grade 3). A 3D-CT angiogram on admission and two four-vessel cerebral angiograms failed to demonstrate a bleeding source. All three patients failed trial EVD clamping, with clinical deterioration and elevated intracranial pressure (ICP). ETV was performed with a 0-degree endoscope in a 4.6-mm irrigating sheath using an endoscopic-coring/"cookie-cut" technique. An EVD was left in place for postoperative ICP monitoring but was clamped. RESULTS: ETV was accomplished in all patients. In one case, a tiny basilar tip aneurysm was seen during the endoscopic procedure. Intraoperatively, the prepontine cistern revealed dense, degraded blood products. Postprocedure ICP measurements were reduced to normal range. Clinical improvement, normal ICP readings, and/or radiographic evidence of resolution of hydrocephalus allowed uneventful removal of the EVD within 36-48 h post-ETV in all patients. All remained headache-free, with a normal neurological examination, during a follow-up period of 10, 11, and 12 months, respectively. CONCLUSION: To our knowledge, this is the first report of ETV for PNH with hydrocephalus and the first report of a basilar tip microaneurysm seen intraoperatively during ETV. ETV is a viable treatment option for refractory hydrocephalus secondary to a perimesencephalic pattern of subarachnoid hemorrhage (SAH). Its early application can avoid placement of a ventriculoperitoneal shunt, curtail the extended use of an EVD, and reduce the associated infection risks. Despite thorough angiographic investigation for an aneurysmal cause of SAH, a "microaneurysm" of the basilar artery was found at ETV. No complication or rebleeding was encountered.

Endoscopic third ventriculostomy in adults: a technique for dealing with the neural (opaque) floor.

OBJECT: An opaque (neural) floor of the third ventricle is considered an obstacle to safe penetration of the floor of the third ventricle in endoscopic third ventriculostomy (ETV). The direct technique of endoscopic coring ("cookie cut") of the opaque (neural) floor of the third ventricle is described in 41 cases among a total of 101 consecutive adult ETVs. METHODS: A 0° endoscope in a 4.6-mm irrigating sheath was used to press and core ("cookie cut") a section of the tuber cinereum, thereby exposing the underlying membranes and vasculature. Thereafter, the endoscopic apparatus was used to penetrate the membrane into the prepontine space. RESULTS: Among 101 consecutive ETVs performed in adults, there were 41 instances of an opaque floor in which the coring technique was used. The basilar artery (BA) complex was in the intended path of penetration in 13 cases. There were no perioperative deaths or vascular injuries. No cases were aborted because of the opaque floor or the configuration of the BA complex. The clinical success rate in the opaque floor group was 80% (33 of 41 patients). CONCLUSIONS: An opaque (neural) floor is frequently seen in adults during ETV. Removing the floor by the core ("cookie cut") method is a safe means of revealing the underlying BA complex and membranous structures prior to penetration into the prepontine cistern. On occasion, the BA complex may be in the path of penetration, and one can maneuver the endoscope to displace the vasculature to successfully accomplish the ETV.

Endoscopic cauterization of a symptomatic choroid plexus cyst at the foramen of Monro: case report.

OBJECTIVE: Choroid plexus cysts are common in the developing fetus, and although often persisting into adulthood, they rarely represent the underlying cause of symptomatic unilateral ventriculomegaly. The case presented here highlights both the diagnostic obscurity and endoscopic management of a choroid plexus cyst in a symptomatic patient. CLINICAL PRESENTATION: The patient is a 47-year-old white woman who presented with acute exacerbation of debilitating, diffuse, and postural headache, nausea, vomiting, early papilledema, and short-term memory loss. Cranial magnetic resonance imaging revealed an intraventricular mass obstructing the foramen of Monro on the left with ventriculomegaly. Cranial computed tomographic imaging demonstrated unilateral ventricular enlargement. INTERVENTION: During stereotactic endoscopic exploration, a choroid plexus cyst was evident at the foramen of Monro. Endoscopic cauterization of the cyst resulted in a decrease in the size of the left lateral ventricle, with complete relief of the patient's headaches and resolution of her memory loss. She remained headache free at the time of a 3-year follow-up evaluation after surgery. CONCLUSION: Choroid plexus cysts remain a diagnostic challenge; their presence should be sought out in the face of ventricular asymmetry and symptomatic hydrocephalus. Endoscopic ablation offers a minimally invasive treatment for the management of these lesions.

Delayed stoma failure in adult communicating hydrocephalus after initial successful treatment by endoscopic third ventriculostomy: case report.

OBJECTIVE: To describe 2 cases of delayed endoscopic third ventriculostomy (ETV) failure in 2 adult patients initially successfully treated for normal pressure hydrocephalus by ETV. The cause of ETV failure was stoma closure, and this was documented in both instances by direct endoscopic inspection. CLINICAL PRESENTATION: In the first case, a 67-year-old woman presented with progressive gait disturbance, incontinence, and memory problems. Brain magnetic resonance imaging exhibited ventricular dilation, including the fourth ventricle, disproportionate to cortical atrophy. In the second case, a 55-year-old man presented with progressive gait disturbance, urinary incontinence, memory problems, and headaches. Brain magnetic resonance imaging exhibited communicating hydrocephalus. INTERVENTION: The first patient underwent an ETV with subsequent improvement in all symptom areas. Three years and 2 months later, she experienced a return of original symptoms and ventricular dilation on brain computed tomography, compared with previous postoperative scans. Direct endoscopic inspection of the third ventricular floor revealed stoma closure secondary to fibrotic scar. The patient subsequently underwent ventriculoperitoneal shunt placement that resulted in symptom improvement. The patient in the second case underwent an ETV that resulted in marked symptom improvement in all areas. Four years and 3 months later, he experienced a return of gait difficulties and headaches. Direct endoscopic inspection showed a lack of cerebrospinal fluid pulsations through the third ventricular stoma and dense arachnoid adhesions around the basilar artery. A repeat ETV was unsuccessful. Subsequent ventriculoperitoneal shunt placement resulted in symptom improvement. CONCLUSION: ETV may provide an effective treatment for patients with normal pressure hydrocephalus, a form of communicating hydrocephalus. Stoma closure can be a mechanism of delayed ETV failure in normal pressure hydrocephalus, consistent with reports of ETV failure in pediatric obstructive hydrocephalus.

Posterior cerebral artery P1 segment at the stoma during endoscopic third ventriculostomy in adults.

OBJECTIVES: A serious catastrophic complication of endoscopic third ventriculostomy (ETV) is basilar artery (BA) damage. Although the BA has been discussed as the cause of haemorrhage and even pseudoaneurysm, variations of the posterior cerebral artery proximal segment (P1) and its protrusion into the third ventricle floor have not been emphasised. A series of cases are reported in which the P1 segment was located at the stoma during an ETV and was at risk of perforation. Precautionary techniques for complication avoidance are described. METHODS: A retrospective review was performed of all ETVs performed in adults at our institution between 2004 and 2008. Cases were identified in which the P1 segment was noted to herniate into the stoma at the time of third ventricular floor fenestration. RESULTS: Among 65 cases reviewed, six were identified in which the P1 segment significantly herniated into an area of the stoma at the time of third ventricular floor fenestration. In no case was the P1 segment injured by the ETV procedure. Each of the six patients had opaque third ventricle floors. A 'cookie cut' technique was used in which the opaque third ventricle floor was abraded to reveal the underlying translucent membrane, offering an improved view of arteries in the basilar cisterns. In four of six patients, ETV resulted in clinical improvement. CONCLUSIONS: The posterior cerebral artery P1 segment is potentially at risk during ETV in adults as well as in children. Awareness and proper precautions may help reduce injuries to either the P1 or the basilar apex during an ETV.

Enlarged thalamostriate vein causing unilateral Monro foramen obstruction. Case report.

Causes of unilateral hydrocephalus resulting from an obstruction at the Monro foramen include foraminal atresia, tumors, gliosis, contralateral shunting, and infectious and inflammatory conditions. However, few reports in the literature cite vascular lesions as the cause of the obstruction. To their knowledge, the authors present the first report of unilateral hydrocephalus occurring due to an abnormally enlarged thalamostriate vein independent of an arteriovenous malformation or developmental venous angioma. The condition was treated successfully by endoscopic septum pellucidum fenestration. A 28-year-old man was referred for evaluation due to a 10-year history of chronic headaches that worsened in severity over the past year. A CT scan of the head revealed unilateral right ventricular dilation. Cranial MR imaging with and without contrast administration showed a dilated right thalamostriate-internal vein complex without any evidence of associated arteriovenous malformation or venous angioma. Endoscopic exploration of the right lateral ventricle showed an enlarged subependymal thalamostriate vein obstructing the Monro foramen. An endoscopic fenestration of the septum pellucidum was performed, resulting in alleviation of the patient's symptoms. Abnormally enlarged venous structures may cause obstructive unilateral hydrocephalus and can be a rare cause of chronic, intermittent headaches in adults. Endoscopic fenestration of the septum pellucidum is an effective treatment.

Neural-dural transition at the medial anterior cranial base: an anatomical and histological study with clinical applications.

OBJECT: Few anatomical studies have been focused on the morphological features and microscopic anatomy of the transition from the intracranial space to the medial anterior cranial base. The authors of the current study performed histological analyses to define the structure of the transition from neural foramina to the cranial base (neural-dural transition) at the cribriform plate, particularly as related to cerebrospinal fluid (CSF) fistula formation and surgical intervention in the region. METHODS: The medial anterior cranial base was resected in six cadaveric specimens. Histological methods were used to study the anatomy of the region on the microscopic level. Results of these examinations revealed a multilayered neural-dural transition at the cribriform plate, which consisted of an arachnoid membrane and a potential subarachnoid space as well as dura mater, periosteum, ethmoid bone, and associated layers of submucosa and mucosa of the paranasal air spaces. A subarachnoid space was identified around the olfactory nerves as they exited the neural foramina of the cribriform plates. The dura mater eventually thinned out and became continuous with the periosteum in the ethmoid bone. The dura, arachnoid membrane, and associated potential subarachnoid space were obliterated at a place 1 to 2 mm into the olfactory foramen. The authors present a case of recurrent CSF rhinorrhea successfully treated using a technique of multilayered reconstruction with pericranium, fat, and bone. CONCLUSIONS: The findings provide an anatomical basis for CSF fistula formation in the region of the cribriform plate and help to explain the unusual presentations in patients who have CSF rhinorrhea and meningitis. These results may facilitate the treatment of CSF fistulas, repair of defects in the medial anterior cranial base, and approaches to tumors and other pathological entities in the region.