Cerebrospinal Fluid Diversion from the Cisterna Magna in Patients with Idiopathic Intracranial Hypertension and Slit Ventricles: Long-Term Effectiveness, Revision Rates, and Clinical Outcomes.

OBJECTIVE: Idiopathic intracranial hypertension (IIH) is a cerebrospinal fluid (CSF) disorder defect that is frequently treated with CSF shunts. Shunts utilizing the cisterna magna as a proximal reservoir have been described in literature; however, long-term outcomes are unknown. The present study aims to describe the long-term effectiveness, revision rates, and clinical outcomes of this shunt in 14 patients with IIH and slit ventricles. METHODS: A single-center retrospective review of 14 IIH patients treated by cisterna magna shunts was performed. Shunt histories, including revision rate and time until first shunt failure for ventricular, lumbar, and cisterna magna shunts were recorded. "Revision rate" was calculated as the total number of shunt revisions over years of total shunt placement. The average follow-up time was 12.08 years. RESULTS: The mean age at first cisterna magna shunt placement was 18.1 years (6.6-43.3 years) and all patients had radiological evidence of slit ventricles. Cisterna magna shunts improved or resolved clinical symptoms for all 14 patients and had a lower rate of revisions (0.42 revision/year) compared to ventricular (0.72 revision/year) and lumbar (1.30 revision/year) shunts. Of the 11 patients still requiring CSF diversion at the end of the study, eight had functioning shunts that utilized the cisterna magna. CONCLUSIONS: The cisterna magna shunt may be a suitable option for patients with IIH and slit ventricles. Further study is needed to understand the clinical utility of this shunt for the population in which it is indicated.

Simple methods for cerebrospinal fluid collection in fetal, neonatal, and adult rat.

BACKGROUND: Cerebrospinal fluid (CSF) collection and its analysis are common medical practices useful in the diagnosis, therapy, and prevention of central nervous system (CNS) disorders. In recent years, several types of research have improved our insight into CSF and its role in health and disease. Yet, many characteristics of this fluid remain to be fully understood. NEW METHODS: Here, we describe how to collect CSF from embryonic, postnatal, and adult stages of the rat. In adults, CSF can be collected through simple stereotaxic surgery to expose the membrane overlying the cisterna magna (CM) of an anesthetized rat and collection of CSF through micropipette puncture through the membrane. In embryos and pups, CSF is aspirated, using a fire-polished micro-capillary pipette, from the CM of animals. RESULTS: Application of these methods provides the maximum volume of pure, uncontaminated CSF (embryonic day 19: 10-15 microliter, postnatal day 5: 20-30 microliter, adults: 100-200 microliter) with a success rate of approximately 95% in every age. COMPARISON WITH EXISTING METHODS: Compared to the existing protocols, these methods obtain considerable volumes of CSF, which may accelerate the measurement of biological markers in this fluid. Also, these techniques do not require surgical skills and according to the practical points mentioned during sampling, the procedures can be performed in rapid fashion. CONCLUSION: We describe simple methods for collecting CSF in live rats. These protocols provide clean, uncontaminated CSF for experiments to understand the exact role of this fluid in the development and maintenance of the CNS health.

Stereotaxic Surgical Approach to Microinject the Caudal Brainstem and Upper Cervical Spinal Cord via the Cisterna Magna in Mice.

Stereotaxic surgery to target brain sites in mice is commonly guided by skull landmarks. Access is then obtained via burr holes drilled through the skull. This standard approach can be challenging for targets in the caudal brainstem and upper cervical cord due to specific anatomical challenges as these sites are remote from skull landmarks, leading to imprecision. Here we outline an alternative stereotaxic approach via the cisterna magna that has been used to target discrete regions of interest in the caudal brainstem and upper cervical cord. The cisterna magna extends from the occipital bone to the atlas (i.e., the second vertebral bone), is filled with cerebrospinal fluid, and is covered by dura mater. This approach provides a reproducible route of access to select central nervous system (CNS) structures that are otherwise hard to reach due to anatomical barriers. Furthermore, it allows for direct visualization of brainstem landmarks in close proximity to the target sites, increasing accuracy when delivering small injection volumes to restricted regions of interest in the caudal brainstem and upper cervical cord. Finally, this approach provides an opportunity to avoid the cerebellum, which can be important for motor and sensorimotor studies.

Suturing of the Arachnoid Membrane for Reconstruction of the Cisterna Magna: Technical Considerations.

BACKGROUND: Postoperative cerebrospinal fluid (CSF) fistula following cranial or spinal surgery is associated with increased morbidity and mortality. To prevent CSF fistulas, various techniques have been described. Here, we describe the arachnoid membrane continuous-running suture technique in cisterna magna reconstruction for preventing postoperative CSF leakage. METHODS: After craniotomy and dural opening, the incision of the arachnoid of the cisterna magna was performed using a diamond blade. To prevent the arachnoid from drying out and shrinking during surgery, it was periodically irrigated with warm saline solution. Posterior fossa surgery was performed. When closing the membranes, the arachnoid membrane was closed with the running-suture technique. After the first surgical knot was made in the cranial end of the arachnoid opening, continuous suturing with a 2-mm distance between the stitches was performed without stretching them. After every 3 stitches, the free end of the thread was pulled gently along the suturing axis, and the edges of the arachnoid were closed. After the arachnoid edges were approximated, the surgical knot was tied. Watertight closure was checked by performing the Valsalva maneuver at the end of the surgery. RESULTS: No CSF leakages were observed after surgery. CONCLUSIONS: Arachnoid membrane suturing seems to be safe and effective in preventing postoperative CSF leakage and CSF-related complications. Using continuous running suturing alone, without any sealant, might be effective in cases with untraumatized arachnoid membrane.

Subtemporal-Transtentorial Approach for Microsurgical Resection of Hemorrhagic Ambient Cistern Arteriovenous Malformation.

Arteriovenous malformations (AVMs) of the ambient cistern are an extremely rare and complex subgroup of vascular malformation, representing a clinical challenge due to the deep-seated, highly eloquent anatomic location and the debilitating, life-threatening consequences related to hemorrhagic presentation and surgical morbidity. Ultimately, a tailored treatment, based on the presenting symptoms, AVM angioarchitecture, and annual risk of hemorrhage should be discussed among a multidisciplinary team to find the best individualized strategy balancing between the pros and cons of each approach. In Video 1, we present the case of a 60-year-old man with a hemorrhaged AVM of the right ambient cistern, present the pros and cons of each possible treatment strategy, and illustrate the successful resection of this lesion through a subtemporal-transtentorial microsurgical approach.

An Uncommon Case of Neuroenteric Cyst Located at the Lateral Cerebellomedullary Cistern.

We present the case of a 42-year-old woman with a 5-week history of headache, progressive dysphagia, dysphonia, and hoarseness. A brain magnetic resonance imaging revealed an extra-axial cyst of the left lateral cerebellomedullary cistern. The subsequent histopathologic examination diagnosed a neuroenteric cyst. This case sheds light on the pivotal role of histologic identification of neuroenteric cyst, which could be crucial for further diagnostic investigations, especially in pediatric patients.

Adult cerebellopontine angle ependymoma presenting as an isolated cisternal mass: A case report.

INTRODUCTION: Ependymomas represent approximately 2%-8% of all primary intracranial brain tumors. The occurrence of extra-axial posterior fossa ependymomas in adults is rare. CASE AND OUTCOMES: We report a case of extra-axial cerebellopontine (CP) angle ependymoma in an adult patient, managed through gross total resection (GTR) and adjuvant radiotherapy. At her one-year postoperative visit, the patient remained clinically stable without any symptoms or focal neurological deficit and a follow up MRI showed no evidence of tumor recurrence. DISCUSSION: Only six cases of adult cerebellopontine angle ependymomas have been reported in the English literature, with the left side affected more commonly. Including this case, the mean age of the reported cases of adult extra-axial CP angle ependymoma is 44.14 years (range 22-66 years). Men accounted for five out of seven cases (71.4%). Maximal surgical resection is the mainstay of treatment in extra-axial CP angle ependymomas. Among seven reported cases, five received GTR and two had subtotal resection (STR). Patients were followed an average of 13.6 months (range 2-30 months) and only two patients with STR died during the follow-up period (6 weeks and 2 months after surgery). Six of the seven reported cases (including this one) received adjuvant radiotherapy. CONCLUSION: Although rare, extra-axial CP angle ependymomas should be considered as a differential diagnosis to other lesions of the CPA. Radical resection, whenever possible, is usually associated with a good outcome. Adjuvant radiotherapy remains an optional treatment with an unknown impact on overall and progression-free survival.

Pioneers in the cisterna magna puncture / Pioneiros na punção da cisterna magna

Abstract At the beginning of the 20th century, cerebrospinal fluid (CSF) collection and analysis emerged as a promising aid in the diagnosis of diseases of the central nervous system. It was obtained through the established procedure of lumbar puncture, described by Heinrich Quinke in 1891. The search for an alternative way to gather the CSF emerged in animal research, highlighting the cisterna magna as a promising source, with relative safety when performed by someone trained. Described initially and in detail by James Ayer in 1920, the procedure was widely adopted by neurologists and psychiatrists at the time, featuring its multiple advantages and clinical applications. After a period of great procedure use and exponential data collection, its complications and risks relegated the puncture of the cisterna magna as an alternative route that causes fear and fascination in modern Neurology.

Resumo No início do século XX, a coleta e análise do líquido cefalorraquidiano (LCR) despontavam como um promissor auxílio no diagnóstico das doenças do sistema nervoso central. Sua obtenção se dava através do consagrado procedimento de punção lombar, descrito por Heinrich Quinke em 1891. A busca por uma via alternativa na obtenção do LCR ganhou destaque nas pesquisas animais, destacando-se na cisterna magna promissora fonte, com relativa segurança quando executada por alguém treinado. Descrito inicialmente e de maneira pormenorizada por James Ayer em 1920, o procedimento foi amplamente adotado por neurologistas e psiquiatras à época, com destaque para suas múltiplas vantagens e aplicações clínicas. Após um período de grande uso do procedimento e exponencial obtenção de dados, suas complicações e riscos relegaram a punção da cisterna magna como via alternativa que causa medo e fascínio na Neurologia moderna.

ATP Measurement in Cerebrospinal Fluid Using a Microplate Reader.

Imbalance in extracellular ATP levels in brain tissue has been suggested as a triggering factor for several neurological disorders. Here, we describe the most sensitive and reliable technique for monitoring the ATP levels in mice cerebrospinal samples collected by cisterna magna puncture technique and quantified using a microplate reader.

A modified park bench position: the "Dormeuse" position.

BACKGROUND: Because of the restricted volume of the cisternal space, proper patient positioning on the operating table is of utmost importance during surgery by retrosigmoid approaches. Three positions are commonly used: supine, with the head rotated to the side contralateral to the lesion; the semi-sitting position; and the park bench position. Each position has advantages and disadvantages, and the surgeon should choose the one best suited to the individual patient and the pathology to be treated. METHODS: We describe a modified park bench position that we call the Dormeuse position. CONCLUSION: The Dormeuse position guarantees decrease in the posterior fossa pressure and allows optimal neural and vascular manipulation and control of any aspect of the cerebellopontine angle.

Efficacy of cyst-cisternal shunt for refractory cyst regrowth of cystic vestibular schwannomas.

Vestibular schwannomas (VSs) are generally benign and slow-growing tumors, and microsurgical resection is the commonly recommended treatment. Some reports suggested that inserting a cystoperitoneal shunt was effective for treatment of cystic VSs; however, there was no report of a cyst-cisternal shunt which diverts cyst fluid into cistern. We report a case of cystic VS with repeated cyst regrowth within weeks after repeated surgeries. We prevented further recurrence using cyst-cisternal shunt. This technique may be a new treatment option for refractory cyst regrowth of cystic VSs.

Cannula Implantation into the Cisterna Magna of Rodents.

Cisterna magna cannulation (CMc) is a straightforward procedure that enables direct access to the cerebrospinal fluid (CSF) without operative damage to the skull or the brain parenchyma. In anesthetized rodents, the exposure of the dura mater by blunt dissection of the neck muscles allows the insertion of a cannula into the cisterna magna (CM). The cannula, composed either by a fine beveled needle or borosilicate capillary, is attached via a polyethylene (PE) tube to a syringe. Using a syringe pump, molecules can then be injected at controlled rates directly into the CM, which is continuous with the subarachnoid space. From the subarachnoid space, we can trace CSF fluxes by convective flow into the perivascular space around penetrating arterioles, where solute exchange with the interstitial fluid (ISF) occurs. CMc can be performed for acute injections immediately following the surgery, or for chronic implantation, with later injection in anesthetized or awake, freely moving rodents. Quantitation of tracer distribution in the brain parenchyma can be performed by epifluorescence, 2-photon microscopy, and magnetic resonance imaging (MRI), depending on the physico-chemical properties of the injected molecules. Thus, CMc in conjunction with various imaging techniques offers a powerful tool for assessment of the glymphatic system and CSF dynamics and function. Furthermore, CMc can be utilized as a conduit for fast, brain-wide delivery of signaling molecules and metabolic substrates that could not otherwise cross the blood brain barrier (BBB).

Ventriculocisternal Shunt Redivivus: Third Ventricle-Cisterna Magna Intradural Shunt: A Technical Note and Case Report.

OBJECTIVE: To present a hitherto unreported modification of the classic Torkildsen procedure: passing a catheter intracranially, between the third ventricle and cisterna magna. METHODS: We applied our technique to a 56-year-old man who presented to our department for treatment of a pineal region mass. RESULTS: The patient was placed in sitting position and the mass was gross totally removed through a supracerebellar infratentorial approach. After the completion of the tumor resection, the patency of the cerebral aqueduct was checked, but the permeability was doubtful. During the same procedure, a shunt was inserted, under direct microsurgical control, into the third ventricle and passed over the cerebellar surface into the cisterna magna. The postoperative course was uneventful, and the patient was discharged from our unit with no neurological deficits and able to carry on with his day-to-day life. CONCLUSIONS: Our case illustrates that ventriculocisternal shunting can successfully be used in selected cases. The variation we describe can be a valuable surgical strategy in patients with pineal region masses, in whom a supracerebellar infratentorial route is used and in whom uncertainty exists regarding the patency of the sylvian aqueduct.

Cisterna magna arachnoid membrane suturing decreases incidence of pseudomeningocele formation and incisional CSF leakage.

OBJECTIVE: A pseudomeningocele and an incisional cerebrospinal fluid leak are considered frequent complications following neurosurgical operations. The rate of these complications especially increases following neurosurgical procedures on the posterior cranial fossae. According to some publications, the rate of pseudomeningoceles has been reported as high as 40%, whereas that of incisional cerebrospinal fluid leaks is up to 17%. For the purposes of reducing the risk of these complications after a midline suboccipital craniotomy, we propose suturing the arachnoid membrane of the cisterna magna. In this paper, we present a retrospective analysis of arachnoid membrane suturing. METHODS: Seventy patients underwent midline suboccipital craniotomy by the first author between 2012 and 2016 at Burdenko Neurosurgery Institute. In this group was included a consecutive group of patients with posterior fossae tumors where the approach was performed through the cisterna magna arachnoid membrane following midline suboccipital craniotomy and dural opening. The patients were divided into two groups. Group 1 included 38 patients to whom cisterna magna arachnoid membrane suturing was performed with monofilament nonabsorbable suture 7.0., and additionally, the suture was sealed with fibrin adhesive sealant TachoComb®. Group 2 included 32 patients without arachnoid membrane suturing. There was no other significant difference in terms of clinical signs and surgical procedures between these groups. In the postoperative period, the frequency of developing a pseudomeningocele and an incisional cerebrospinal fluid leak was assessed in these two groups. The results were evaluated on the basis of clinical, CT, and MRI data performed in the postoperative period. RESULTS: In the patients who underwent arachnoid membrane suturing (group I), pseudomeningocele formation was observed in one (2.6%) and CSF leak in one (2.6%) of the 38 patients. In group II, in which patients had no arachnoid membrane suturing, we observed pseudomeningocele formation in 11 (34.4%) patients and a CSF leak in 7 (25.0%) out of 28 patients with known follow-up. Statistical analysis of the data indicates a significantly higher risk of postoperative pseudomeningocele formation and/or an incisional cerebrospinal fluid leak in a group of patients who did not undergo arachnoid membrane suturing (p < 0.05). CONCLUSIONS: Suturing of the arachnoid membrane of the cisterna magna and its further sealing with fibrin adhesive sealant TachoComb® create an additional barrier for preventing cerebrospinal fluid collection in the extradural space. This technique significantly reduces the risk of postoperative pseudomeningocele formation and/or an incisional cerebrospinal fluid leak in patients with midline suboccipital craniotomy.

An optimized technique of endoscopic third ventriculocisternostomy (ETV) for children with occlusive hydrocephalus.

In this article, we present an optimized minimally invasive technique of ETV for children with occlusive hydrocephalus. The study comprises of 64 consecutive pediatric cases (34 boys and 30 girls aged from 1 month to 5 years) of occlusive hydrocephalus from various etiologies, which were treated with a modified technique of ETV. Mean clinical follow-up period after ETV was 24.2 ± 3.8 months. Application of the new technique made it possible to significantly reduce the length of the soft tissue incision for access, and the use of upgraded instruments allowed to perform a twist drill hole in the skull to less than half a usual size. Access to the brain and lateral ventricle was performed by blunt trephination of the dura without the need for significant corticectomy or coagulation, and yielded minimal damage to the brain, which is very important in patients of young age. Continued endoscopic control during the approach down to the lateral ventricle increases safety and decreases risk of injury, and can be performed in cases of pathologies affecting the anatomical relationships of the lateral and third ventricle. Mortality in our cohort was 0%, and there were no postoperative neurological, endocrinological, or infectious complications. Patency rates of the first ETV performed was 78%, with the remaining patients requiring additional surgical procedures for complicated settings. This new technique of minimally invasive ETV placement in pediatric patients is an effective and safe method to treat occlusive hydrocephalus and can be recommended for extensive clinical use.

Solitary Cysticercal Cyst Inside the Blake's Pouch Remnant of Mega Cisterna Magna with Associated Aqueductal Stenosis: Clinical and Management Implications.

BACKGROUND: Intraventricular and subarachnoid forms represent the relatively complex, albeit uncommon, manifestations of central nervous system involvement by cysticercal cysts. Cysticercal encystation inside the Blake's pouch remnant of mega cisterna magna (MCM) remains an extremely rare clinical scenario that, to the best of our knowledge, has not been reported previously. CASE PRESENTATION: A 12-year-old boy presented with acute worsening and subsequent spontaneous resolution of his compensated hydrocephalus. Neuroimaging revealed features consistent with a MCM with septum inside, indicating remnants of the embryologic fourth ventricular diverticulum, the Blake's pouch. It also revealed a free-floating intact cysticercal cyst inside the MCM limited by the septum with aqueductal stenosis. The spontaneous clinicoradiologic resolution of hydrocephalus raised the possibility of ball valve obstruction of the cerebrospinal fluid outflow, i.e., Bruns syndrome. We successfully treated this patient with endoscopic extraction of the viable cysticercal cyst through a suboccipital burrhole. CONCLUSIONS: The clinical scenario presented here has not been described previously. Endoscopic cyst removal in such a situation is an effective and low-risk procedure that obviates the further need for antihelminthic medications.

Cisterna magna meningiomas without dural attachment: Report of two cases.

Meningiomas within the cisterna magna without dural attachment are extremely rare. To the best of our knowledge, only three cases of meningiomas within the cisterna magna have been reported in the literature. The authors present two cases of patient with the cisterna magna meningioma without dural attachment. (Case 1) A 36-year-old female presented with a 10-month history of numbness in the left hand. Magnetic resonance imaging (MRI) disclosed the presence of a contrast-enhanced tumor in the posterior fossa. A suboccipital craniectomy was performed, and the tumor located within the cisterna magna with no attachment to the dura. Diagnosis is made as clear cell meningioma. The postoperative course was uneventful, and a recurrence has not been observed for three years. (Case 2) A 58-year-old man presented with a well-circumscribed mass in the posterior fossa. At surgery, the tumor located within the cisterna magna with a connection to the right tenia. The tumor was totally removed without neurological deficits. At a 7-year follow-up, no evidence of a recurrence was observed. It is quite difficult to preoperatively diagnose as a cisterna magna meningioma without dural attachment. However, complete removal of the tumor should be achieved.

Transaqueductal trans-Magendie fenestration of arachnoid cyst in the posterior fossa.

BACKGROUND: Neuroendoscopy is currently recommended as the first choice to treat posterior fossa arachnoid cysts. It has proven to be effective, providing improved outcome, and safe, having a low complication rate. Compared to craniotomy and shunt placement, it has lower surgical morbidity, minimizing or avoiding risks of subdural fluid collections, shunt infection, malfunction, overdrainage, and dependence. Usually, rigid scopes maneuvered through a suboccipital approach are used. When symptomatic obstructive hydrocephalus develops, CSF diversion is the first aim of surgery. METHODS: In these patients, a flexible scope introduced through a frontal burr hole allows not only immediate and efficient management of hydrocephalus with endoscopic third-ventriculostomy, but in selected cases also direct cyst inspection and fenestration. Navigation of an enlarged cerebral aqueduct is actually safe when performed by experienced neurosurgeons. RESULTS: We describe the cystocisternostomy of a cisterna magna arachnoid cyst using a transaqueductal trans-Magendie approach. CONCLUSIONS: This minimally invasive technique gives the possibility of performing both endoscopic third-ventriculostomy and cyst fenestration, which alone may not be enough to efficiently treat hydrocephalus.

The Role of Endoscopic Assistance in Ambient Cistern Surgery: Analysis of Four Surgical Approaches.

OBJECTIVE: We used microscopy with endoscopic assistance to conduct an objective analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric (OI), subtemporal (ST), and transchoroideal (TC). In addition, we performed a parahippocampalis gyrus resection in the ST context. METHODS: Each approach (SC, OI, ST, TC) was performed on 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the 30-degree endoscope was used to explore the exposure. The parahippocampalis gyrus was resected through an ST approach and the exposure was evaluated. The quantitative analysis was based on linear exposure of the vascular structures (linear exposure), such as the posterior choroidal artery (PChA), the P2 and P3 segments of the posterior cerebral artery (PCA) with their branches, the basal vein of Rosenthal, and the area of exposure of the ambient cistern region (area of exposure) limited by points on its superior, mesial, and anterior walls. In all cases, a P value of less than 0.05 was considered significant. RESULTS: There was a significant difference (P < 0.05) in linear exposure of the PCA and medial PChA between microsurgery and endoscopic assistance using the ST approach. This approach also improved the medial, superior, and total exposure of the ambient cistern region. CONCLUSIONS: This study demonstrates that endoscope assistance improved exposure of the ambient cistern region when using the ST approach. Endoscopic assistance provided similar surgical exposure compared with ST associated with parahippocampalis resection.

Neuroendoscopic Ventriculocisternostomy with Stent Placement for Trapped Temporal Horn After the Resection of Glioblastoma.

BACKGROUND: Endoscopic ventriculostomy is an attractive surgical alternative to ventriculoperitoneal shunt in the treatment of focal hydrocephalus, including trapped temporal horn (TTH). The major concern of this surgical approach is closure of a stoma, the risk of which may be minimized by placement of a stent after ventriculostomy. CASE DESCRIPTION: The authors report a case of a 60-year-old man with glioblastoma in the corpus callosum and the parietal lobe who developed TTH after partial tumor resection. After the failure of a ventriculoperitoneal shunt, endoscopic ventriculocisternostomy was chosen over the revision of the shunt. A stoma was placed at the medial wall of the dilated temporal horn. Endoscopic inspection confirmed communication with the interpeduncular cistern, but the collapsed lateral ventricle after fenestration suggested the risk of stoma closure. Therefore, a ventricular tube was placed through the stoma as a stent to secure its flow. No further surgical intervention was needed, and the patient was able to complete radiochemotherapy without cessation. CONCLUSIONS: The risk of recurrence of TTH after endoscopic ventriculocisternostomy may be minimized by combining ventriculostomy with stent placement. This surgical procedure would be beneficial, particularly in cases of TTH associated with malignant brain tumors, where the risk of delay or interruption of adjuvant oncologic treatments may negatively impact patient prognosis.