Pathogenesis and management of low-pressure hydrocephalus: A narrative review

Patients diagnosed with low-pressure hydrocephalus typically present with enlarged ventricles and unusually low intracranial pressure, often measuring below 5 cmH2O or even below atmospheric pressure. This atypical presentation often leads to low recognition and diagnostic rates. The development of low-pressure hydrocephalus is believed to be associated with a decrease in the viscoelasticity of brain tissue or separation between the ventricular and subarachnoid spaces. Risk factors for low-pressure hydrocephalus include subarachnoid hemorrhage, aqueduct stenosis, prior cranial radiotherapy， ventricular shunting, and cerebrospinal fluid leaks. For potential low-pressure hydrocephalus, diagnostic criteria include neurological symptoms related to hydrocephalus, an Evans index >0.3 on imaging, ICP ≤ 5 cm H2O, symptom improvement with negative pressure drainage, and exclusion of ventriculomegaly caused by neurodegenerative diseases. The pathogenesis and pathophysiological features of low-pressure hydrocephalus differ significantly from other types of hydrocephalus, making it challenging to restore normal ventricular morphology through conventional drainage methods. The primary treatment options for low-pressure hydrocephalus involve negative pressure drainage and third ventriculostomy. With appropriate treatment, most patients can regain their previous neurological function. However, in most cases, permanent shunt surgery is still necessary. Low-pressure hydrocephalus is a rare condition with a high rate of underdiagnosis and mortality. Early identification and appropriate intervention are crucial in reducing complications and improving prognosis.

A case of rapid deterioration in a subacute period after endoscopic third ventriculostomy

Background: Although generally a safe procedure, serious postoperative complications after endoscopic third ventriculostomy (ETV) for obstructive hydrocephaly have been rarely reported, such as delayed obstruction of the stoma at the third ventricle floor.Case description: A 20-year-old male was referred to our department because of severe headache and diplopia. A pineal tumour and obstructive hydrocephaly were detected in preoperative imaging. After tumour biopsy and ETV, the reduction of ventricle size and improvement of headaches were immediately observed. On the seventh day, however, he developed a rapidly progressing consciousness disturbance due to severe hydrocephalus leading to urgent secondary ETV. The original ventriculostomy stoma at the third ventricle floor was completely occluded by scar adhesion. The patient recovered well as previously and received additional treatment.Conclusion: Although very rare, occlusion of the ventriculostomy stoma can postoperatively occur in the subacute period. Patients undergoing ETV for obstructive hydrocephalus due to a pineal tumour should be carefully monitored to avoid serious consequences.

Aberrant Arterial Anatomy at the Floor of the Third Ventricle: Video Case Report

A 65-year-old woman presented with a 2-month progressive history of forgetfulness, headaches, and decline in mobility. Imaging showed a large, enhancing pineal region tumor with triventricular hydrocephalus. She underwent an endoscopic third ventriculostomy and biopsy after appropriate consent was gained. Video 1 demonstrates the endoscopic procedure during which 2 aberrant arteries were identified at the floor of the third ventricle. The endoscopic third ventriculostomy was performed between these 2 arteries with great care to preserve them. The patient improved postoperatively with resolution of the hydrocephalus. Histology showed a metastatic malignant melanoma. To the best of our knowledge, no similar anatomy has been shown in an endoscopic procedure. We speculate that these are perforating arteries from the posterior communicating artery (premamillary artery) or a branch from the first part of the posterior cerebral artery P1 (thalamoperforators). Other options include perforators from the ophthalmic segment of the internal carotid artery, the communicating segment of the internal carotid artery, the superior hypophyseal artery, or a branch of the medial posterior choroidal arteries. We look at each in turn.

Endoscopic third ventriculostomy limited by artery of Percheron

The irrigation of the thalamus depends mainly on the thalamoperforating arteries. There are many anatomical variations in these arteries, the best known being the artery of Percheron. We report a case of a 13-year-old male presented with headache and decline in his mental status. Imaging features showed obstructive hydrocephalus secondary to a mass at the level of the mesencephalon so an endoscopic third ventriculostomy was performed. During the procedure a thalamoperforating artery was encountered at the level of the tuber cinereum limiting the perforation of the third ventricle floor. The present case emphasizes the importance of knowing the anatomy of these arteries and the identification of their main variants during neurosurgical procedures.

Biomechanics of brain tissue damage caused by fiber endoscope penetration in third ventriculostomy surgery

Third ventriculostomy is the preferred treatment for obstructive hydrocephalus, but the biomechanics of brain tissue damage caused by fiber endoscopes remains unclear. In this study, brain tissue material parameters were tested based on the Ogden model to simulate needle puncture mechanics, and replicated the entire fiber endoscope advancement process during third ventriculostomy. It was found that a smaller diameter fiber endoscope, a perpendicular puncture angle, and a faster puncture speed would decrease the damage of brain tissue caused by the fiber endoscope. This study provides valuable insights for optimizing the instrumentation and surgical process of third ventriculostomy.

Neuroendoscopy in the management of pineal region tumours in children

INTRODUCTION

Pineal region tumours (PRTs) are more common in children and represent a wide variety of lesions. The practise of a radiation test dose is obsolete and a biochemical/histological diagnosis is recommended before further therapy. Many patients present with hydrocephalus. Advances in neuroendoscopic techniques have allowed safe and effective management of this obstructive hydrocephalus with an opportunity to sample cerebrospinal fluid (CSF) and obtain tissue for histopathology. Definitive surgery is required in less than a third. Endoscopic visualisation and assistance is increasingly used for radical resection, where indicated.

METHODOLOGY

Our experience of endoscopic surgery for paediatric PRTs from 2002 to 2021 is presented. All patients underwent MRI with contrast. Serum tumour markers were checked. If negative, endoscopic biopsy and endoscopic third ventriculostomy (ETV) were performed; and CSF collected for tumour markers and abnormal cells. For radical surgery, endoscope-assisted microsurgery procedures were performed to minimise retraction, visualise the extent of resection and confirm haemostasis.

RESULTS

M:F ratio was 2:1. The median age of presentation was 11 years. Raised ICP (88.88%) was the commonest mode of presentation. Nineteen patients had pineal tumours, one had a suprasellar and pineal tumour, one had disseminated disease, while six had tectal tumours. The ETB diagnosis rate was 95.45%, accuracy rate was 83.3% and ETV success rate was 86.96%.

CONCLUSION

Neuroendoscopy has revolutionised the management of paediatric PRTs. It is a safe and effective procedure with good diagnostic yield and allows successful concurrent CSF diversion, thereby avoiding major surgeries and shunt implantation. It is also helpful in radical resection of lesions, where indicated.

Loculated hydrocephalus: is neuroendoscopy effective and safe? A 90 patients' case series and literature review

INTRODUCTION

Loculated hydrocephalus is a complex condition in which different non-communicating compartments form within the ventricular system due to different etiology, mainly intraventricular hemorrhage and infection. Since the end of the twentieth century, neuroendoscopy has been explored as a therapeutic option for loculated hydrocephalus with non-univocal results.

METHODS

We performed a retrospective analysis of 90 patients who underwent endoscopic treatment for loculated hydrocephalus from January 1997 to January 2021 (mean age: 2 years, range 7-21). We included 37 (41.1%) children with multiloculated hydrocephalus, 37 (41.1%) with isolated lateral ventricle, 13 (14.4%) with excluded temporal horn, and 3 (3.3%) with isolated fourth ventricle. We compared our results with those available in literature.

RESULTS

A mean of 1.91 endoscopic procedure/patient were performed (only one endoscopy in 42.2% of cases). Complications of neuroendoscopy and of shunt surgeries were recorded in 17 (18.9%) and 52 (57.8%) children, respectively. Twenty-six (28.9%) children were shunt-free at the last follow-up, 47.8% have only one shunt.

DISCUSSION

The first goal of neuroendoscopy is to increase the rate of shunt-free patients but, when it is not possible, it aims at simplifying shunt system and reducing the number of surgical procedures. In our series, neuroendoscopy was able to achieve both these goals with an acceptable complication rate. Thus, our results confirmed neuroendoscopy as a valid tool in the long-term management of loculated hydrocephalus. Neuronavigation and intraoperative ultrasound could increase the success rate in cases with distorted anatomy.

ETV as treatment for obstructive hydrocephalus in an aneurysmal malformation of the vein of Galen in infants: case report and review of literature

INTRODUCTION

A vein of Galen aneurysmal malformation (VGAM) is a high-flow arteriovenous malformation that typically presents in early childhood. Complications associated with this condition include heart failure and hydrodynamic disorders resulting from high blood flow. Hydrocephalus is one of the hydrodynamic disorders. It can present in a chronic form due to a defect in the absorption of cerebrospinal fluid (CSF) resulting from venous hypertension or in an acute/subacute form due to obstruction of normal circulation routes caused by the mass effect of the VGAM. Currently, endovascular closure of the lesion is considered the treatment of choice. However, in acute/subacute presentations of obstructive hydrocephalus, progression may occur despite endovascular treatment, necessitating a cerebrospinal fluid diversion procedure. Prior to the advent of endoscopic treatment, ventricular shunts were utilized, but outcomes were poor due to the pathological hydrodynamic parameters associated with the malformation. The role of endoscopic third ventriculostomy as a treatment option in these situations remains unclear, and there is limited literature available. Therefore, we present the case of a patient with a vein of Galen aneurysmal malformation and obstructive hydrocephalus, which was treated via ETV. Furthermore, a literature review was conducted.

CASE DESCRIPTION

We present a 5-month-old infant who was diagnosed at birth with VGAM. At 2 months of age, a partial closure of the malformation was performed via endovascular. Subsequently, the patient presented at the emergency department with symptoms of irritability, lethargy, vomiting, feeding refusal, and "setting sun" sign of several days' duration due to obstructive hydrocephalus. The patient was successfully treated via ETV. Following this, a new arteriography was performed and revealed occlusion of the VGAM. The child clinically improved and currently exhibits mild psychomotor impairment after 1-year follow-up.

CONCLUSION

In the literature, there are a limited number of reports on the treatment of obstructive hydrocephalus associated with VGAM via ETV. These reports have demonstrated good outcomes with minimal surgical complications. Our patient also exhibited good results. As such, ETV is a viable and safe option for the treatment of obstructive hydrocephalus associated with VGAM in pediatric patients. However, more research is needed to establish the effectiveness of ETV in comparison to other treatment options and to understand the long-term outcomes.

Endoscopic transventricular approach for the resection of a hemorrhagic cavernous malformation of the tectal plate: Operative video

Background

Cavernomas of the third ventricle are rare entities that provide significant therapeutic challenges. Because of the better view of the surgical field and the possibility to achieve a gross total resection (GTR), microsurgical approaches are more commonly used to target the third ventricle. Endoscopic transventricular approaches (ETVA), on the other hand, are minimally invasive procedures that can afford a straight corridor trough the lesion, avoiding bigger craniotomies. Moreover, these approaches have shown lower infectious risks and shorter hospitalization times.

Case Description

A 58-year-old female patient accessed the Emergency Department complaining of headache, vomiting, mental confusion, and syncopal episodes for the past 3 days. An urgent brain computed tomography scan revealed a hemorrhagic lesion of the third ventricle, conditioning triventricular hydrocephalus, so an external ventricular drainage (EVD) was placed in an emergency setting. An magnetic resonance imaging (MRI) showed a 10 mm diameter hemorrhagic cavernous malformation originating from the superior tectal plate. An ETVA was performed for the cavernoma resection, followed by an endoscopic third ventriculostomy. After proving shunt independence, the EVD was removed. No clinical nor radiological complications were assisted in the postoperative period, so the patient was discharged 7 days after. The histopathological examination was consistent with cavernous malformation. An immediate postoperative MRI showed GTR of the cavernoma with a little clot around the surgical cavity, which appeared completely reabsorbed 4 months later.

Conclusion

ETVA provides a straight corridor to the third ventricle, excellent visualization of the relevant anatomical structures, safe resection of the lesion, and treatment of the concomitant hydrocephalus by ETV.

Chiari III malformation with defect in Liliequist membrane on MR imaging

The Liliequist membrane is a radiologically neglected structure, with routine evaluation only carried out in pre-operative and post-operative cases of third ventriculostomy. We report two cases of Chiari III malformation in two unrelated females with similar findings on magnetic resonance imaging study including occipital and low cervical encephalocele, hydrocephalus, and segmentation anomalies in cervical spine. Along with these findings, we report a flow void on T2-weighted images observed in both cases across the site of Liliequist membrane between interpeduncular and chiasmatic cistern. Our findings of CSF flow across the Liliequist membrane may represent spontaneous third ventriculostomy or another congenital defect in the myriad of anomalies seen in cases of Chiari III malformation.

Racemose neurocysticercosis simulating tuberculous meningitis

We report a patient with racemose neurocysticercosis, highlighting the diagnostic and management issues. A 37-year-old male had headaches, fever, and seizures for 8 months. He had a positive tuberculin test, cerebrospinal fluid pleocytosis, and hydrocephalus and exudates on MRI. His symptoms rapidly resolved following antitubercular and prednisolone treatment. After 2 months, he was readmitted with headache and vomiting, and his brain MRI revealed communicating hydrocephalus with a cyst in the lateral ventricle and subarachnoid space, which was confirmed as neurocysticercosis on the third ventriculostomy. The patient was managed with dexamethasone and a ventriculoperitoneal shunt. This case highlights that meningitis symptoms, CSF pleocytosis, and positive tuberculin tests may not always suggest tubercular etiology.

Evaluation of third ventriculostomy outcome by measuring optic nerve sheath diameter in adult hdyrocephalus

OBJECTIVE

It is difficult to demonstrate the success of the procedure in patients with third ventriculostomy. We evaluated that optic nerve sheath diameter (ONSD) measurement, which can reflect intracranial pressure, may be a criterion for decision of endoscopic third ventriculostomy (ETV) success.

METHODS

28 adult patients suffering long overt standing ventriculomegaly (LOVA) who performed ETV were included in this retrospective study. The patients were divided into two groups as successful (group A) and failed ETV group (group B) according to their postoperative evaluation. ONSD was measured on pre- and post-operative computed tomography (CT) and Evan's index (EI), diameter of third ventricule (V3), the patency of ETV stoma and periventricular edema were evaluated by magnetic resonance imaging (MRI).

RESULTS

The mean ONSD was measured as 6.39±0.92mm for the right eye, 6.50±0.91mm for the left eye on preoperative CT. The mean ONSD by CT (after surgery) was 4.89±0.87mm for the right eye, 5.02±0.1mm for the left eye (p<0.05). Postoperative group A and group B were compared according to ONSD measurement; mean ONSD in group A was 4.52±0.69mm for the right and 4.59±0.9mm for the left, mean ONSD in group B was 5.82±0.51mm for the right and 6.1±0.32mm for the left (p<0.05). The best ONSD value for detecting failed ETV was 5.40mm (sensitivity 90%, specifity 75%, AUROC 0.938) for right and 5.91mm (sensitivity 90%, specifity 75%, AUROC 0.950) for left. EE was measured as 0.39±0.12mm on preoperative MRI and 0.39±0.12mm on postoperative MRI (p=0.3). V3 was measured as 14.7±2.47mm on preoperative MRI and 10.47±1.99mm on postoperative MRI (p<0.05).

CONCLUSION

The statistical values obtained from study show that the ONSD measurement can help in the postoperative evaluation of patients, who had a ETV surgery.

Hydrocephalus secondary to dengue encephalitis in an infant: case report

BACKGROUND

Dengue is the leading cause of mosquito-borne viral infection. It is responsible for high morbidity and mortality in children living in endemic areas. Nowadays, neurological complications are progressively referred to and include a broad spectrum of symptoms. It can be secondary to metabolic alterations, direct invasion by the virus, and enhanced autoimmune response.

CASE PRESENTATION

Here, we report a rare case of hydrocephalus secondary to dengue encephalitis. A 13-day-old boy was diagnosed with dengue. He evolved with seizures and impaired consciousness being diagnosed with encephalitis. After clinical treatment, he was discharged fully recovered. Three months later, he presented with signs and symptoms of intracranial hypertension. Brain MRI revealed hydrocephalus secondary to acquired aqueduct stenosis. The patient underwent an endoscopic third ventriculocisternostomy.

CONCLUSION

Dengue infection is a differential diagnosis for acute febrile neurological impairment in children from endemic areas. Follow-up should be offered after dengue encephalitis to detect possible late-onset complications, as hydrocephalus.

Evaluation of third ventriculostomy outcome by measuring optic nerve sheath diameter in adult hdyrocephalus

OBJECTIVE

It is difficult to demonstrate the success of the procedure in patients with third ventriculostomy. We evaluated that optic nerve sheath diameter (ONSD) measurement, which can reflect intracranial pressure, may be a criterion for decision of endoscopic third ventriculostomy (ETV) success.

METHODS

28 adult patients suffering long overt standing ventriculomegaly (LOVA) who performed ETV were included in this retrospective study. The patients were divided into two groups as successful (group A) and failed ETV group (group B) according to their postoperative evaluation. ONSD was measured on pre- and post-operative computed tomography (CT) and Evan's index (EI), diameter of third ventricule (V3), the patency of ETV stoma and periventricular edema were evaluated by magnetic resonance imaging (MRI).

RESULTS

The mean ONSD was measured as 6.39±0.92mm for the right eye, 6.50±0.91mm for the left eye on preoperative CT. The mean ONSD by CT (after surgery) was 4.89±0.87mm for the right eye, 5.02±0.1mm for the left eye (p<0.05). Postoperative group A and group B were compared according to ONSD measurement; mean ONSD in group A was 4.52±0.69mm for the right and 4.59±0.9mm for the left, mean ONSD in group B was 5.82±0.51mm for the right and 6.1±0.32mm for the left (p<0.05). The best ONSD value for detecting failed ETV was 5.40mm (sensitivity 90%, specifity 75%, AUROC 0.938) for right and 5.91mm (sensitivity 90%, specifity 75%, AUROC 0.950) for left. EE was measured as 0.39±0.12mm on preoperative MRI and 0.39±0.12mm on postoperative MRI (p=0.3). V3 was measured as 14.7±2.47mm on preoperative MRI and 10.47±1.99mm on postoperative MRI (p<0.05).

CONCLUSION

The statistical values obtained from study show that the ONSD measurement can help in the postoperative evaluation of patients, who had a ETV surgery.

External validation of the ETV success score in 313 pediatric patients: a Brazilian single-center study

The endoscopic third ventriculostomy (ETV) success score (ETVSS) was developed to predict the success rate of ETV at 6 months. In this study, the authors assessed the performance of this score for > 6 months, i.e., at 12 months, and provided external validation in Brazilian children. All children undergoing first ETV (without choroid plexus cauterization) at a Brazilian single institution for > 20 years were included in the study. The ETVSS was retrospectively calculated for each patient and compared with the actual success of the procedure observed at 6 and 12 months after the procedure. A total of 313 eligible children underwent initial ETV, 34.18% of whom had undergone shunt placement before ETV. The most common etiologies were aqueductal stenosis (45%) and non-tectal brain tumors (20.8%). ETV was successful at 6 months in 229 patients (73.16%) compared with the 61.3% predicted by the ETVSS. The overall actual success rate observed at 1 year after ETV was 65.1% (204 patients). The area under the receiver operating characteristic curve was 0.660 at 6 months and 0.668 at 1 year, which suggested a tendency for the ETVSS to underestimate the actual success rate of ETV at both timepoints. The ETVSS showed good success prediction in accordance with the actual ETV success rate and proved to be useful during the decision-making process of ETV.

Frameless radiosurgical third ventriculostomy: Technical report

Background:

We describe the technical report and results of the first image-guided, linear accelerator, frameless radiosurgical third ventriculostomy.

Methods:

We report a 20 years old man, with diplopia, balance disturbances, and limitation for gaze supraversion. Magnetic resonance imaging resonance imaging of the brain and cranial computed tomography showed showed a left thalamic-midbrain lesion that caused partial compression of the Silvio aqueduct and mild ventricular dilatation. The biopsy revealed the diagnosis of pleomorphic xanthoastrocytoma. Before radical treatment of the tumor with fractionated stereotactic radiotherapy, the patient underwent to frameless radiosurgical third ventriculostomy, on the TrueBeam STX® platform with the ExacTrac localization system. The target used was the one defined on the floor of the third ventricle, at the midpoint between the mammillary bodies and the infundibular recess. The prescription dose was 120 Gy, given using a monoisocentric technique of multiple noncoplanar circular arches. The geometric arrangement of the plan consisted of 15 arches, with a 4 mm cone, distributed over a 110° table.

Results:

There was symptomatic and image improvement two days after radiosurgery. On CT, a reduction in ventricular dilation was observed with a reduction in the Evans index from 0.39 (initial CT) to 0.29 (CT at 15 days). In 3.0T magnetic resonance image at 3 months, we showed the third ventriculostomy. There have been no treatment failures or complications.

Conclusion:

It is possible to effectively perform the frameless radiosurgical third ventriculostomy without associated morbidity in the short term.

Burr hole microsurgery in treatment of patients with intracranial lesions: Experience of 44 clinical cases

BACKGROUND

Modern technical capabilities have made minimally invasive surgery increasingly popular. Small incisions can reduce surgical duration and the degree of tissue trauma, which reduces the risk of complications. Burr hole microsurgery is a relatively new minimally invasive technique used in neurosurgery. The objective of this study was to assess the feasibility and outcomes of using burr hole microsurgery for the management of intracranial lesions.

METHODS

Forty-four adults were treated with burr hole microsurgery. Patients were divided into groups according to the presence of (1) brain tumors (n = 20); (2) congenital brain cysts (n = 16); (3) cavernous angiomas (n = 3); and (4) neurovascular conflicts of the 5th cranial nerve (n = 5). All surgical interventions were performed using the "MARI" device.

RESULTS

The transcortical approach was used to remove 16 brain tumors, and 2 brain tumors were biopsied. In the two tumor biopsy cases, the parasagittal interhemispheric route was used. Gross total resection was achieved in 10 cases (62.5%) when tumor size reached up to 4 cm, subtotal resection was achieved in four cases (25%) in large tumors, and partial resection in two cases (12.5%). In patients with congenital cysts, cavernous angiomas, trigeminal neuralgia, and symptomatic regression were noted the postoperative period. The surgical duration was 30-180 min (median, 75 min). A hemorrhagic complication was observed in one case. Significant postoperative complications and mortality were not observed.

CONCLUSION

Burr hole microsurgery can treat different intracranial lesions effectively. Despite a smaller craniotomy diameter of 11-14 mm compared with keyhole approaches, surgery was successful.

Three-Dimensional versus 2-Dimensional Endoscopic Third Ventriculostomy: Surgical Results of a Preliminary Comparative Study

BACKGROUND

Three-dimensional (3-D) endoscopes have been widely used for a large variety of approaches in neurosurgical practice. However, in the last decade, 3-D scopes were barely used for ventricular surgery. In this study, we illustrated our preliminary experience with a 3-D endoscope for third ventriculostomy using new dedicated endoscopic equipment.

METHODS

Over a 12-month period, a high-definition 3-D endoscopic third ventriculostomy (ETV) was performed in 14 patients with obstructive hydrocephalus. Patients were followed prospectively and compared retrospectively with a matched group of 16 similar patients who underwent ETV with a standard 2-dimensional (2-D) endoscope. Surgical outcome and intra- and postoperative course were retrospectively reviewed.

RESULTS

3-D ETV provided excellent surgical results, and no significant difference was shown in terms of outcome, complication, and length of hospitalization between the 2 groups. Moreover, operative time (minutes) was significantly shorter in the 3-D group than the 2-D ETV group (19.9 ± 4.8 vs. 22.9 ± 1.4, respectively; P < 0.05), and the use of the 3-D endoscope provided subjective improvements of depth perception, hand-eye coordination, and surgeon comfort.

CONCLUSIONS

Our preliminary study clearly demonstrated the effectiveness of 3-D ETV and provided a significant reduction of operative time. Depth information from the 3-D scope appears to facilitate rapid and stable ETV maneuvers, representing a critical development that may become a valuable tool for neuroendoscopy.

Design and validation of a 3D-printed simulator for endoscopic third ventriculostomy

BACKGROUND

Simulation-based training has been considered as the most promising curriculum for neurosurgical education to finally improve surgical skills with the greatest efficiency and safety. However, most of the simulators including physical models and virtual reality systems are relatively expensive, which limits their promotion. In this study, the authors tried to develop a realistic, low-cost, and reusable simulator for endoscopic third ventriculostomy (ETV) and evaluate its validity.

METHODS

A 3D-printed rigid skull with the ventricular system originated from a de-identified patient with obstructive hydrocephalus was constructed. The third ventricular floor was designed as a replaceable module. Thirty-nine neurosurgeons tested the simulator and a rating system was established to assess their performance. All participants filled out questionnaires to evaluate the simulator after training. Five neurosurgical students were recruited to finish the whole training for ten times in order to explore the learning curve of ETV.

RESULTS

We found that (1) the more experienced surgeons performed obviously better than the rather inexperienced surgeons which verified that our model could reflect the ability of the trainees; (2) as the training progressed, the scores of the post-graduates increased and the fifth training average score was obviously higher than their first training average score. The feedback questionnaires showed the average scores for value of the simulator as a training tool and global rating were 3.15 and 3.54 (on a 4-point scale).

CONCLUSION

Our model was practical for ETV training. The results of our program showed that our model could precisely reflect the operators' ability to perform ETV and could make it more efficient to master basic skills.

The Basal Subarachnoid Cisterns: Surgical and Anatomical Considerations

The basal subarachnoid cisterns are expansions of the subarachnoid space and transmit cranial nerves and intracranial vessels. Providing neurosurgeons with key concepts, anatomical landmarks, and techniques can result in safer procedures and better patient outcomes. In this review, we discuss the major basal subarachnoid cisterns including their embryology, history, anatomical descriptions, and use during surgical approaches.

Neurogenic Bladder Dysfunction as Signal of Late Failure of Endoscopic Third Ventriculostomy in Child with Spina Bifida

BACKGROUND

Endoscopic third ventriculostomy (ETV) is an option for hydrocephalus treatment in patients with myelomeningocele, mostly after a previous shunt dysfunction. Late failure of ETV is a rare event, traditionally associated with dramatic symptoms of intracranial hypertension. In patients with myelodysplasia and neurogenic bladder dysfunction, urodynamic deterioration can be a signal of neurologic worsening as a consequence of tethered cord or shunt problems.

CASE DESCRIPTION

We describe here a rare case of a 12-year-old female patient with myelomeningocele and evidence of a failure 10 years after a previously successful ETV whose initial symptoms were worsening of urinary complaints. After 2 months, she was admitted to the emergency department with seizures and acute hydrocephalus and was shunted.

CONCLUSIONS

Pediatric neurosurgeons must follow myelomeningocele patients with successful ETV for a long time and take care of subtle alterations of organic functions that have a close relationship with central nervous system integrity. A multidisciplinary approach can facilitate this strategy and avoid a tragic outcome.

Clinical Management of Prostate Cancer Metastasis to Pineal Gland: Case Report and Review of Literature

BACKGROUND

Prostate cancer is the most common cancer among American men, with an incidence of approximately 233,000 cases per year. Intracranial metastases are rare and, specifically, metastasis to the pineal gland has only been reported in 2 postmortem cases in the literature.

CASE DESCRIPTION

We present the first documented case of confirmed prostate cancer metastasis to the pineal gland in a living patient. The patient underwent an endoscopic third ventriculostomy and pineal lesion biopsy with complete resolution of his hydrocephalus and presenting symptoms. His biopsy results confirmed the prostate origin of the metastasis, and he subsequently underwent stereotactic radiosurgery for treatment of this lesion.

CONCLUSIONS

This is the first report of the clinical management of metastatic prostate cancer to the pineal region and description of the clinical outcome. Although prostate cancer is the most common cancer in American men, metastasis to the pineal has only been reported twice from autopsy examinations. Overall, pineal tumors in the geriatric population are exceedingly rare and the age and comorbidities in this patient made management quite unique.

Cryptococcal meningitis in an immunocompetent patient with obstructive hydrocephalus: A case report

BACKGROUND

Cryptococcal infections of the central nervous system are very rare in immunocompetent patients. They usually present as meningitis or as fungal cysts with or without hydrocephalus. Rapid diagnosis and treatment is crucial to the prognosis.

CASE REPORT

We report the case of an immunocompetent 40-year-old male patient with no medical or surgical history and no recent travel, who was hospitalized in our neurosurgery department because of a rapidly worsening headache. The neurological examination revealed no focal deficit but worrying signs of increased intracranial pressure. Magnetic resonance imaging (MRI) with contrast showed thick and large-scale cortico-pial cerebellar enhancements, associated with severe obstructive hydrocephalus. This required emergency endoscopic ventriculocisternostomy during which we observed cottony tissues along the ventricular walls. Biopsied tissues and cerebrospinal fluid samples (CSF) were not contributive. A CT scan of the chest and abdomen and blood markers of common primary tumors were all negative. No evidence of HIV infection or any cause of immunosuppression was identified. Symptoms and a second MRI slightly improved with intravenous corticosteroid therapy. The hypothesis of a lymphoma or granulomatous disease was made initially for which direct surgical biopsies were scheduled. The diagnosis of cryptococcal meningitis was obtained later on by simultaneous plasma and CSF Cryptococcus antigen detection. Cryptococcus neoformans (formerly C. neoformans var. grubii [serotype A]) was then identified by PCR. Clinical improvement was obtained with antifungal therapy.

CONCLUSION

Cryptococcal meningitis is a well-known condition in immunocompromised patients, often causing hydrocephalus requiring neurosurgical management. The diagnosis is more difficult in patients with no history of HIV or organ transplant. Neurologists and neurosurgeons must consider this possibility in case of diffuse, thick leptomeningeal enhancement on MRI.

Evaluation of hydrocephalus patients with 3D-SPACE technique using variant FA mode at 3T

The major advantages of three-dimensional sampling perfection with application optimized contrasts using different flip-angle evolution (3D-SPACE) technique are its high resistance to artifacts that occurs as a result of radiofrequency or static field, the ability of providing images with sub-millimeter voxel size which allows obtaining reformatted images in any plane due to isotropic three-dimensional data with lower specific absorption rate values. That is crucial during examination of cerebrospinal-fluid containing complex structures, and the acquisition time, which is approximately 5 min for scanning of entire cranium. Recent data revealed that T2-weighted (T2W) 3D-SPACE with variant flip-angle mode (VFAM) imaging allows fast and accurate evaluation of the hydrocephalus patients during both pre- and post-operative period for monitoring the treatment. For a better assessment of these patients; radiologists and neurosurgeons should be aware of the details and implications regarding to the 3D-SPACE technique, and they should follow the updates in this field. There could be a misconception about the difference between T2W-VFAM and routine heavily T2W 3D-SPACE images. T2W 3D-SPACE with VFAM imaging is only a subtype of 3D-SPACE technique. In this review, we described the details of T2W 3D-SPACE with VFAM imaging and comprehensively reviewed its recent applications.

Higher Failure of Endoscopic Third Ventriculostomy in Infants: The "Distensible" Skull Is the Culprit

The efficacy of endoscopic third ventriculostomy (ETV) in childhood strongly correlates with age. Reasons for the higher failure rate in infants are under debate but the "distensible" head with its immature skull (which would prevent an adequate flow through the ETV and/or a sufficient pressure gradient between the cortical subarachnoid spaces and the venous sinuses) has been suggested as a possible cause. Our evidence of spontaneous conversion of a failed, but always patent, third ventriculostomy into an effective one occurring in a child after maturation of the skull supports this hypothesis.

Assessment of Liliequist membrane by 3D-SPACE technique at 3 T

INTRODUCTION

Liliequist membrane (LM) is the most important anatomic structure for the success of endoscopic third ventriculostomy (ETV). Identification of this membrane is difficult with conventional MRI techniques. The purpose of this retrospective study is to determine the impact of three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) sequence with variant flip-angle mode (VFAM) in the assessment of LM at 3-T MRI devices.

METHODS

3D-SPACE with VFAM images were obtained in 445 patients. LM visibility and integrity were scored as 0 (good), 1 (moderate), and 2 (poor) on these images for each parts (sellar, diencephalic, and mesencephalic) and overall of the membrane.

RESULTS

According to the LM overall integrity scores, 11 % (48 cases) of the patients had perforated membrane. According to subsegmental integrity scores, sellar part was completely intact in 63 % of patients, diencephalic segment was completely intact in 60 % of the patients, and mesencephalic segment was completely intact in 95 % of the patients. Visibility scores of the third ventricle inferior wall were significantly higher in the patients with intact LM (p = 0.001). There was not any statistically significant relationship between LM pattern and overall integrity (p = 0.352). LM attachment sites could be detected easier in the patients who had better visibility of third ventricle inferior wall or intact LM (p < 0.001 for both).

CONCLUSION

3D-SPACE technique is a useful alternative for the evaluation of morphology, integrity, individual variations, topographic relationships, and visibility of LM since it has some advantages including lower SAR values, fewer artifacts, and high-resolution images.

Initial Experience with High-Definition Camera-On-a-Chip Flexible Endoscopy for Intraventricular Neurosurgery

OBJECTIVE

The usefulness of existing neuroendoscopes has been limited by either decreased range of motion or suboptimal image resolution. The flexible high-definition chip-camera endoscope has emerged as a potential solution to the shortcomings of available instruments by combining superior flexibility and image quality in order to better operate within spatially constrained intraventricular operations.

CASE DESCRIPTION

Here we describe a 36-year-old woman who presented with hydrocephalus caused by an obstructive mass arising from the tectum. A high-definition camera-on-a-chip flexible neuroendoscope was used to sample the tectal mass after a traditional neuroendoscope was used to perform a third ventriculostomy.

CONCLUSIONS

As demonstrated by this initial experience, the use of high-definition camera-on-a-chip flexible endoscopy may provide enhanced intraoperative visualization and application for intraventricular neurosurgery.

Aqueduct Stent Placement: Indications, Technique, and Clinical Experience

OBJECTIVE

Complicated hydrocephalus, such as trapped fourth ventricle, is challenging. Aqueduct stent placement is a possible alternative to the conventional multiple shunts approach. This article discusses the indications, techniques, and clinical experiences of aqueduct stent placement.

METHODS

We retrospectively analyzed a series of 10 consecutive patients with hydrocephalus and had aqueduct stent placement between February 2009 and May 2014. The clinical and imaging data were collected and the indications, technique, and clinical experience of aqueduct stent placement were analyzed and discussed.

RESULTS

Among the 10 patients (mean age, 38 years; range, 5 months-69 years), 8 patients harbored an obstructive hydrocephalus caused by aqueductal obstruction. The underlying pathology consisted of intraventricular tumor in 3 patients, intraventricular cysticercosis in 2, and membranous or inflammatory obstruction in 3 patients. Two patients presented with trapped fourth ventricle, which resulted from Dandy-Walker malformation and shunt placement, respectively. Aqueduct stents were placed endoscopically in 8 patients, whereas the other 2 were placed microscopically. There were no deaths due to aqueduct stent placement. Postoperatively, all of the patients showed improvement or resolution of their symptoms. After an average follow-up period of 27 months (range, 1-51 months), recurrence of aqueductal obstruction has not been observed. In 1 patient, there was a complication of transient oculomotor paralysis after aqueduct stent placement. A stent migration was observed in 1 patient after remaining stable for 4 years.

CONCLUSIONS

Aqueduct stent placement is technically feasible and can be useful in selected patients either with endoscopy or open surgery.

Liliequist membrane: radiological evaluation, clinical and therapeutic implications

In a simplistic and succinct way, Liliequist membrane may be understood as a projection formed by an arachnoid membrane extending from the dorsum sellae to the mammillary bodies. In spite of being well known to neurosurgeons, many radiologists neither know this anatomical structure nor give importance to its study. The imaging evaluation of this membrane is feasible and may be interesting for a better preoperative planning; postoperative evaluation of third ventriculostomies; and understanding of suprasellar arachnoid cysts and perimesencephalic hemorrhage. The present article illustrates the anatomy of the membrane, with emphasis on imaging findings, besides describing its possible clinical and surgical implications.

[Endoscopic approach to ventricular atrium for biopsy of pineal region tumour: case report]

INTRODUCTION

The usual endoscopic approach in the management of pineal region tumours consists of inserting the scope into the frontal horn of the lateral ventricle and advancing it through the foramen of Monro into the third ventricle. We report the case of a patient with a pineal tumour on whom we used an endoscopic approach through the ventricular atrium to obtain a biopsy by opening the choroidal fissure.

CLINICAL CASE

This young 25-year-old man presented with headache and double vision. Papilloedema and Parinaud's syndrome were found on physical examination. Cranial magnetic resonance revealed a pineal mass and hydrocephalus. We initially performed a third ventriculostomy and a tumour biopsy through a frontal burr hole. The tissue sample was not useful for pathological diagnosis and we decided to perform a second endoscopic biopsy.

CONCLUSIONS

The endoscopic approach to pineal region masses, reaching the ventricular atrium through a parietal burr hole and opening the choroidal fissure, makes it possible to take a biopsy using a single endoscopic approach without needing to cross other ventricular structures.

Cranial growth restriction, a fundamental measure for success of the endoscopy in children under 1 month of age. Is it possible to improve the outcome?

BACKGROUND

Endoscopic third ventriculostomy has been shown to be efficient for the treatment of non-communicating hydrocephalus. However, it is not recommended as the first option in the treatment of obstructive hydrocephalus in children under 3 months of age, because the success rate is less than 35%.

METHODS

We reviewed all the cases of triventricular hydrocephalus treated between 2007 and 2011 in patients under 1 month of age in the case of normal term births or under 1 month of corrected age, in the case of pre-term births. The first treatment option was endoscopic fenestration and a restriction of cranial volume during the two months after surgery.

RESULTS

Ten patients under 1 month of age underwent 13 ventriculostomies for non-communicating hydrocephalus of varying etiology (suprasellar arachnoid cyst (3), stenosis of the Sylvian aqueduct (2), post-infectious meningitis (3), and intrauterine bleeding (2)). Three required surgical endoscopic revision at 3, 4, and 5 months, respectively, after the initial surgery due to progressive ventricular enlargement. One of these three patients presented with Klebsiella pneumoniae ventriculitis as a complication after the second endoscopy. After a mean follow-up of 32 months, none has required a shunt.

CONCLUSIONS

In our limited experience in triventricular hydrocephalus in patients under 1 month, the third ventriculostomy technique may be a better option than the shunt in selected cases.