The Roof of the 4th Ventricle Seen From Inside: Endoscopic Anatomic Illustration-A Case Series

BACKGROUND

The anatomy of the roof of the fourth ventricle has been illustrated in many laboratory investigations, but in vivo reports of the roof anatomy and its variants are still lacking.

OBJECTIVE

To describe the topographical anatomy of the roof of the fourth ventricle explored through a transaqueductal approach that overcomes cerebrospinal fluid depletion, displaying in vivo anatomic images possibly quite close to normal physiological conditions.

METHODS

We critically reviewed the intraoperative video recordings of our 838 neuroendoscopic procedures, selecting 27 cases of transaqueductal navigation that provided good quality image details of the anatomy of the roof of the fourth ventricle. Twenty-six patients affected by different forms of hydrocephalus were therefore categorized into three groups: Group A: blockage of the aqueduct-aqueductoplasty, Group B: communicating hydrocephalus, and Group C: tetraventricular obstructive hydrocephalus.

RESULTS

Group A has shown what the roof of a normal fourth ventricle really looks like albeit the structures seemed overcrowded because of the narrow space. Images from groups B and C paradoxically allowed a more distinct identification of the roof structures flattened by ventricular dilation, making them more comparable with the topography traced on the laboratory microsurgical studies.

CONCLUSION

Endoscopic in vivo videos and images provided a novel anatomic view and an in vivo redefinition of the real topography of the roof of the fourth ventricle. The relevant role of cerebrospinal fluid was defined and outlined, as well as the effects of hydrocephalic dilation on some structures on the roof of the fourth ventricle.

Where the central canal begins: endoscopic in vivo description

OBJECTIVE

Although evidence and descriptions of the central canal (CC) along the medulla oblongata and the spinal cord have been provided by several anatomical and radiological studies, a clear picture and assessment of the opening of the CC, or apertura canalis centralis (ACC), into the fourth ventricle is lacking, due to its submillimetric size and hidden position in the calamus scriptorius.

METHODS

The authors reviewed all of their cases in which patients underwent ventricular transaqueductal flexible endoscopic procedures and selected 44 cases in which an inspection of the region of the calamus scriptorius had been performed and was suitable for study inclusion. Patients were divided into different groups, based on the presence or absence of a chronic pathological process involving the fourth ventricle. In each case, the visual appearance of the opening of the CC of the ACC was classified as no evidence (A0), indirect evidence (A1), or clear evidence (A2). Morphometric measurements were inferred from surrounding structures and the size of surgical tools visible in the field.

RESULTS

The opening of the CC could be clearly observed in all cases (A1 4.5%, A2 95.5%). In normal cases, a lanceolate shape along the median sulcus was most frequently found, with an average size of 600 × 250 µm that became rounded and smaller in size in cases of hydrocephalus. The distance between the caudal margin of the ACC and the obex was about 1.8 mm in normal cases, 2.1 mm in cases of obstructive hydrocephalus, and 1 mm in cases of normal pressure hydrocephalus. The two wings of the area postrema, variable in size and shape, were sited just caudal to the opening.

CONCLUSIONS

A flexible scope inserted through the cerebral aqueduct can approach the hidden calamus scriptorius like a pen fits into an inkpot. With this privileged viewpoint, the authors provide for the first time, to their knowledge, a clear and novel vision of the opening of the CC in the fourth ventricle, along with the precise location of this tiny structure compared to other anatomical landmarks in the inferior triangle.

Homologous amniotic membrane as a dural substitute in decompressive craniectomies

INTRODUCTION

A dura mater substitute in decompressive craniectomies must protect the brain while providing a dissection plane between the cortex and myocutaneous layer. The human amniotic membrane (AM) has anti-inflammatory, wound healing, and differentiation properties. We tested AM properties as a dural substitute by comparing the outcomes to biological ones.

METHODS

We prospectively collected data on 25 patients who randomly underwent decompressive craniectomy with lyophilized AM patches and 25 in which biological substitutes were utilized between 2015 and 2019. The AM was laid with the epithelial side facing the brain because of the anti-adhesive proprieties, while the chorion facing the myocutaneous flap. We collected data on demographics, neurological status, comorbidities, and surgical outcomes. Additionally, we created a score - dura mimicking score- and reviewed postoperative imaging and pathological specimens.

RESULTS

The majority (96%) of AM grafts were integrated into native dura. Thirteen patients scored as excellent and 11 good on our "dura mimicking score", showing tissue integration ability but no cerebral cortex adhesion. The histopathological analysis showed that AM had thick plates of dense fibrous tissue with small reactive vessels, reactive fibroblasts, and lymphocytes infiltrate. The AM group's first outcomes were not different from the biological substitute patients but higher integration rate to the dura and less adhesion to the myocutaneous flap in AM patients.

CONCLUSIONS

We documented the anti-adhesive, protective, and integrative properties of AM dural substitute patches in patients who underwent decompressive craniectomies, comparing the intraoperative differences and postoperative outcomes to biological dural substitutes.

Opto-chiasmatic apoplexy as a compartment syndrome? Anatomical and surgical considerations on two bleeding cavernous malformations

OBJECTIVE

Opto-chiasmatic (OC) cavernous malformations are sporadic lesions that are often misdiagnosed clinically and radiologically. Presenting symptoms range from incidental findings to the more frequent and dramatic "chiasmal apoplexy." The present study aims to evaluate the potential role of arachnoidal membranes of the basal cisterns in the onset of OC apoplexy. A possible mechanism resembling a compartment syndrome is discussed through the description of two cases of bleeding cavernomas.

METHODS

We describe clinical, radiological, intraoperative findings in two cases of young patients presenting with OC apoplexy from bleeding cavernoma. The first was a 38-year-old man diagnosed with optic neuritis at the first episode of visual acuity deterioration. The second patient was a 22 -year-old woman who suffered two OC apoplexy episodes from a recurrence, which also presented with bleeding.

RESULTS

Both patients were operated on via pterional craniotomy and presented a postoperative improvement of visual symptoms. The second patient experienced deterioration 30 months after surgical resection due to rebleeding from a recurrence and required a second operation. Follow-up revealed a good recovery of visual disturbances; MRI at 6 and 3 years showed in both patients an apparent complete removal of the cavernous malformations.

CONCLUSION

The cisternal environment where OC cavernous malformations develop and the paradigm of a compartment syndrome could explain the clinical presentation variability. This very rare subset of cavernomas would benefit from a classification system using ad hoc neuroimaging protocols and consistent indications.

New perspectives in the endoscopic treatment of brain purulent collections: targets, techniques, results in a case series, and overview of the literature

BACKGROUND

Purulent intracranial infections are threatening conditions. Different surgical approaches have been described, respecting the rationale of evacuating the fluid component of the purulent collection. Emerging evidence supports the use of the endoscope for the treatment of cerebral abscesses and subdural empyemas; especially the peculiarities of flexible endoscopes could potentially offer a more effective and conclusive management as compared with the drainage through catheters. We describe our experience in the treatment of intracranial purulent collections with flexible endoscopy, comparing it with the most recent literature.

METHODS

Ten patients affected by intracranial suppuration were treated with endoscopy at our institution. The neurosurgical technique is thoroughly described. The related literature is reviewed, providing a comprehensive overview on the endoscopic treatment of intracranial suppuration so far.

RESULTS

All the patients had a good clinical outcome, with no peri-operative complications. The postoperative scans showed significant radiological improvement, with important reduction of the pus volume. In all cases, the microbiological cultures showed positivity.

CONCLUSIONS

In our experience, the use of the flexible scope proved feasible and effective in the treatment of intracranial purulent collections. Visual awareness of the internal capsule is not limited to a direct inspection of the fluid pus; it rather allows an active removal of the more solid (and perhaps more microbiologically significant) fibrinoid component, and also assists in final bleeding control and in assessing the extent of the evacuation. The steering capabilities of the fiberscope are particularly suitable for such purposes, allowing sampling the solid internal layer of the pyogenic membrane, and potentially shedding light on the actual clinical significance of this component of the abscess.

A light on the dark side: in vivo endoscopic anatomy of the posterior third ventricle and its variations in hydrocephalus

OBJECTIVE

Despite the technological advancements of neurosurgery, the posterior part of the third ventricle has always been the "dark side" of the ventricle. However, flexible endoscopy offers the opportunity for a direct, in vivo inspection and detailed description of the posterior third ventricle in physiological and pathological conditions. The purposes of this study were to describe the posterior wall of the third ventricle, detailing its normal anatomy and surgical landmarks, and to assess the effect of chronic hydrocephalus on the anatomy of this hidden region.

METHODS

The authors reviewed the video recordings of 59 in vivo endoscopic explorations of the posterior third ventricle to describe every identifiable anatomical landmark. Patients were divided into 2 groups based on the absence or presence of a chronic dilation of the third ventricle. The first group provided the basis for the description of normal anatomy.

RESULTS

The following anatomical structures were identified in all cases: adytum of the cerebral aqueduct, posterior commissure, pineal recess, habenular commissure, and suprapineal recess. Comparing the 2 groups of patients, the authors were able to detect significant variations in the shape of the adytum of the cerebral aqueduct and in the thickness of the habenular and posterior commissures. Exploration with sodium fluorescein excluded the presence of any fluorescent area in the posterior third ventricle, other than the subependymal vascular network.

CONCLUSIONS

The use of a flexible scope allows the complete inspection of the posterior third ventricle. The anatomical variations caused by chronic hydrocephalus might be clinically relevant, in light of the commissure functions.

Classification of orbitocranial wooden foreign body penetration injuries: what to do when they violate the intracranial space? A systematic review

INTRODUCTION

Orbitocranial wooden foreign body (OWF) penetrations are rare but challenging occurrences that may violate the intracranial space resulting in brain damage and hemorrhagic, as well as infectious, complications. Moreover, there is a specific subset of cases of OWF penetrations that are particularly challenging to treat. Although there are well-defined management guidelines for pure intraorbital localization, there is not yet a defined treatment protocol for foreign bodies reaching the intracranial space. However, their removal performed either directly or through craniotomy, is often easily attainable given the condition that all necessary precautions are accounted for.

EVIDENCE ACQUISITION

After having treated a 48-year-old man with a transorbital OWF penetration injury at our neurosurgical department, we systematically reviewed the last 15 years of literature to define and summarize the best management strategy. Multiple databases were searched for case reports and case series involving patients with intraorbital and transorbital OWF penetration injuries. For each study, we extracted data on age, sex, imaging modality, type of wood (processed vs. unprocessed), location of periorbital and intracranial entry site, treatment type ("pull and see" or "open and see"), antibiotic therapy, and complications.

EVIDENCE SYNTHESIS

We classified transorbital OWFs into two categories: transorbital with only cavernous sinus involvement and transorbital with more extensive intracranial involvement. We described what we believed was the most appropriate management conduct in each case.

CONCLUSIONS

Grounded on our experience and on the review of the literature, we suggest, based on the anatomical localization of the OWF, a classification system for OWFs which is coupled with a tailored treatment strategy for each case. These suggestions are made to provide surgeons with direction on the correct management of such rare but challenging occurrences.

Over ten years overall survival in glioblastoma: A different disease?

PURPOSE

The reasons why a specific subset of glioblastoma (GBM) patients survive longer than others is still unclear. This study analyzed a cohort of long-term and very-long-term GBM survivors to determine which genetic alterations or patient's characteristics influence survival time.

METHODS

We retrospectively reviewed a cohort of GBM patients treated at our institution over the last 20 years, stratifying patients in three groups: those with a survival time ≥ 36 months and < 120 months (LTS), ≥120 months (VLTS), and < 36 months, respectively. Clinical (age, sex, focality, resection degree, Karnofsky performance status), and immunohistochemical and molecular data (Ki-67 expression and multiple genes alterations) were collected. We then utilized principal component analysis, logistic regression, and Cox proportional hazard models to identify those variables associated with survival.

RESULTS

Younger age at presentation (HR = 0.36, 95% CI 0.21-0.67, p = .001), and MGMT promoter [(MGMTp), methylated, HR = 0.57, CI 0.34-0.96, p = .034) were associated with higher odds of VLTS survival. The multivariate analysis showed how the combination of younger age (< 50 years), Ki-67 < 10%, and the coexistence of TERTp not mutated, MGMTp methylated, and IDH1/2 mutated in the same patient are also associated with higher odds of survival (HR = 0.10, CI 0.01-0.74, p = .025).

CONCLUSIONS

We confirmed younger age at presentation and MGMTp methylation as the only independent factors associated with VLTS. The exceptional survival of our VLTS patients is probably associated with different, still understudied, gene mutations, or with the coexistence of multiple factors.

Form follows function: estimation of CSF flow in the third ventricle-aqueduct-fourth ventricle complex modeled as a diffuser/nozzle pump

OBJECTIVE

In the last 20 years, researchers have debated cerebrospinal fluid (CSF) dynamics theories, commonly based on the classic bulk flow perspective. New hypotheses do not consider a possible hydraulic impact of the ventricular morphology. The present study investigates, by means of a mathematical model, the eventual role played by the geometric shape of the "third ventricle-aqueduct-fourth ventricle" complex in CSF circulation under the assumption that the complex behaves like a diffuser/nozzle (DN) pump.

METHODS

DN pumps are quite recent devices introduced as valveless micropumps in various industrial applications given their property of driving net flow when subjected to rhythmic pulsations. A novel peculiar DN pump configuration was adopted in this study to mimic the ventricular complex, with two reservoirs (the ventricles) and one tube provided with a conical reach (the aqueduct-proximal fourth ventricle). The flow was modeled according to the classic equations of laminar flow, and the external rhythmic pulsations forcing the system were reproduced as a pulsatile pressure gradient between the chambers. Several physiological scenarios were implemented with the integration of data acquired by MRI in 10 patients with no known pathology of CSF dynamics, and a quantitative analysis of the effect of geometric and hydraulic parameters (diverging angle, sizes, frequency of pulsations) on the CSF net flow was performed.

RESULTS

The results showed a craniocaudal net flow in all the given values, consistent with the findings of cine MRI studies. Moreover, the net flow estimated for the analyzed cohort of patients ranged from 0.221 to 0.505 ml/min, remarkably close to the values found on phase contrast cine MRI in healthy subjects. Sensitivity analysis underlines the pivotal role of the DN configuration, as well as of the frequency of forcing pressure, which promotes a relevant net flow considering both the heart and respiration rate.

CONCLUSIONS

This work suggests that the geometry of the third ventricle-aqueduct-fourth ventricle complex, which resembles a diverter, appears to be functional in the generation of a net craniocaudal flow and potentially has an impact on CSF dynamics. These conclusions can be drawn by observing the analogies between the shape of the ventricles and the geometry of DN pumps and by recognizing the basis of the mathematical model of the simplified third ventricle-aqueduct-fourth ventricle complex proposed.

Prone versus sitting position in pediatric low-grade posterior fossa tumors

PURPOSE

The choice between sitting and prone position to access the infratentorial space in a suboccipital craniotomy is still a matter of debate. The comparisons in terms of complications and outcome of both positions are scarce, and the pediatric population is indeed more infrequent in these in scientific reviews. In this paper, we assess intraoperative and postoperative complications and neurological outcome in pediatric patients undergoing posterior cranial fossa surgery for pilocytic astrocytoma in sitting and prone position respectively.

METHODS

We retrospectively analyzed 30 consecutive patients undergoing surgery for cerebellar pilocytic astrocytoma at the two neurosurgical units referring to the University of Padova Medical School from 1999 to 2017. Preoperative, intraoperative, and postoperative data were retrieved from our medical archives.

RESULTS

The statistical analysis did not show any differences between the two groups in terms of preoperative, intraoperative, and postoperative data. The neurological status at last follow-up was similar in both groups of patients.

CONCLUSIONS

Our results suggest that both sitting and prone position can be considered safe in suboccipital craniotomies. Further studies are needed to show if there are possible differences between these positions for other frequent pediatric tumors such as medulloblastomas and ependymomas.

Homologous cryopreserved amniotic membrane in the repair of myelomeningocele: preliminary experience

OBJECTIVE

Surgical management of spinal dysraphism often requires the use of dural substitutes. Amniotic membrane (AM) has drawn the interest of clinicians for its valuable concentration of cytokines and factors capable of promoting wound healing, re-epithelialization, inhibiting fibrosis and regulating angiogenesis. These beneficial qualities could make AM an interesting dural substitute for spina bifida repair. In this study, we describe the use of banked homologous AM as a dural substitute for the repair of spinal dysraphism in newborns. Our purpose is to test the mechanical characteristics, as well as the safety and effectiveness of AM in preventing postoperative complications and re-tethering.

METHODS

The AM patch was carefully detached from the chorion of donors undergoing caesarean section, rinsed in saline solution, and cryopreserved in liquid nitrogen. Five newborns were treated using AM: three affected by open spinal dysraphism and two by spina bifida occulta. The AM patch was used as a dural substitute with two different positions and purposes: the amnion-side down covering the placode to prevent adhesions or placed extradurally facing the dura to avoid scarring and facilitating the sliding of the dural sac itself under the extradural tissue layers.

RESULTS

No adverse events occurred, and the surgical wounds healed without complications. MRI scans taken at 3 and 6 months after surgery showed a satisfying de-tethering of the spinal cord with no obvious evidence of new adherence formation.

CONCLUSIONS

We present a multimodal interposition technique using AM as a reconstructive and anti-adhesive tissue for the treatment of open myelomeningocele (MMC) and lipomeningocele (LMC) treatment. In our experience, AM proved its efficacy in restoring the dural sac integrity without complications. We support the use of AM as a promising dural substitute, speculating on how the use of AM could potentially change reconstructive strategies for spinal dysraphism.

The subependymal microvascular network revealed by endoscopic fluorescence angiography

BACKGROUND

The subependymal vascularization of the cerebral ventricles has been described in anatomical studies on human specimens. Its identification in vivo during neuroendoscopic navigation could have anatomical interest and may lead to a safer ventricular navigation, also avoiding unexpected bleeding. The traditional endoscopic visualization allows the certain identification of only the main vessels. In this study we describe the features of the subependymal vascular network (SEVN) enhanced by sodium fluorescein (SF) angiography. We compare these findings with the vascular patterns visible under white light to evaluate the sensitivity of this technique in unveiling the most distant branches of the SEVN.

METHODS

We reviewed the video records of 39 fluorescein-assisted neuroendoscopic procedures. Steerable fiberscopes equipped with a dual observation mode for both white light and fluorescence were used. After preliminary inspection of the ventricular cavities, the camera was switched to the blue light fluorescent mode. Identical portion of ventricular walls observed in both modalities were compared and analyzed to enhance potential differences of the vascular features.

RESULTS

The main veins were positive (fluorescein enhanced) in 10 patients (25.6%), vessels of smaller diameter visible also under white light presented a detectable fluorescence in 27 patients (69.2%), the micro SEVN, not visible under with light, was revealed by SF in 21 patients (53.8%).

CONCLUSIONS

Fluorescein-guided neuroendoscopy deserves closer investigation since it allows detection of small vessels, not otherwise visible, in the ventricle walls. This method could be applied to ameliorate the knowledge of the environment the surgeon is working on, leading as a result to a safer navigation, also by avoiding minor bleedings.

Treatment of Posttubercular Syringomyelia Not Responsive to Antitubercular Therapy: Case Report and Review of Literature

Posttubercular adhesive arachnoiditis is a rare, late complication of tubercular meningitis. Syringomyelia can develop as a consequence of intramedullary cystic lesions and cerebrospinal fluid (CSF) flow disturbance around the spinal cord, even after successful chemotherapy. We reviewed the literature related to posttubercular syringomyelia treatment and suggest a new combined surgical approach. A 25-year-old Nigerian male patient presented with legs numbness, urinary disturbance, and legs weakness. Spinal magnetic resonance revealed a T5-T7 syringomyelia, secondary to adhesive spinal arachnoiditis related to a history of tuberculous meningitis. Adhesiolysis by direct visualization with a flexible endoscope was performed and a handmade S-italic syringe-subdural shunt was placed to restore CSF flow. During the postoperative course, the neurological deficits improved together with the resolution of the syrinx. Long-term magnetic resonance imaging follow-up documented no recurrences or shunt displacements. We suggest that, when antitubercular therapy is not effective to resolve postarachnoiditis syrinx, arachnolysis with a flexible endoscope together with the placement of an S-italic shunt allowed free CSF communication between the syrinx and the subarachnoid space. Furthermore, we support that the use of an s-shaped shunt could prevent displacement or migration of the device and allows an easier revision in case of acute or late complications.

Fluorescein-Guided Neuroendoscopy for Intraventricular Lesions: A Case Series

BACKGROUND: The benefits of neuroendoscopy in the pathological diagnosis of intra- and paraventricular tumors have already been shown in many neurosurgical studies. However, most authors agree that neuroendoscopic biopsies are not infrequently inconclusive due to small or inadequate samples, prompting the need for new diagnostic strategies.

OBJECTIVE: To describe a technique not previously reported in the literature, combining neuroendoscopy with angiofluorescein guidance for the pathological diagnosis of intra- and paraventricular tumors.

METHODS: The 4-mm steerable fiberscope used was equipped with dual observation modes for white light and fluorescein. Access was by the classical precoronal burr hole. After inspecting the ventricular system in white light, a 10-mg/kg dose of fluorescein sodium (FS) was administered intravenously to the patient. The endoscope was then switched to the blue light fluorescent mode to better localize the pathological tissue. The protocol had been submitted to the local ethics committee.

RESULTS: From September 2011 to March 2015, 9 consecutive patients (aged 1-56 yr) harboring intra- and paraventricular lesions prospectively underwent angiofluorescein-guided endoscopy. In all cases, a pathological diagnosis was obtained without complications. In 5 patients, an endoscopic third ventriculostomy, and, in 1 patient, a septostomy was performed during the same procedure. Fluorescein guidance definitely modified our site of biopsy in 4 cases.

CONCLUSION: In our experience, FS has proven to be a strong enhancer of all ventricular lesions presenting with a disrupted blood–brain barrier, including inflammatory processes. Fluorescein-guided neuroendoscopy appears to be a safe, economic method to improve diagnostic potential in ventricular lesions.

Osteoblastoma Mimicking an Idiopathic Intracranial Hypertension Syndrome

Osteoblastomas are rare, benign bone tumors mainly arising from the long bones and the posterior vertebral arches. Skull localizations account for approximately 15% of cases. A total amount of thirty cases involving the temporal bone are reported in the literature. Clinical presentation of temporal osteoblastomas often includes local pain and swelling, while 7^th and 8^th cranial nerve impairment is rare. We report the novel finding of increase intracranial pressure syndrome secondary to dominant transverse-sigmoid sinus junction compression caused by a small temporal bone osteoblastoma. Excision of the tumor with the restoration of venous flow in the sigmoid sinus was followed by a prompt clinical improvement. In the management of patients with a venous sinus compression, restoration of venous drainage should be a priority.

Aspiration of parafalcine empyemas with flexible scope

PURPOSE

Subdural empyemas are considered neurosurgical emergencies, and the parafalcine location is particularly insidious. We revised the experience of general surgeons who are used to manage chronic pleural purulent collections with video-assisted thoracoscopy.

METHODS

With a similar technique, we successfully aspirated a parafalcine empyema using a flexible scope avoiding a more invasive craniotomy. A review of the treatment options of empyematous collections is also provided, focusing particularly on the hazardous parafalcine location.

RESULTS

The management of subdural empyemas poses different decision-making problems compared to common brain abscesses, urging a more rapid and holistic surgical treatment with minimally invasive approach. Endoscopic aspiration of parafalcine empyema was followed by complete recovery in our patient.

CONCLUSIONS

Flexible endoscopy is a promising method to obtain complete pus removal even from loculated collections through a bur hole, avoiding large craniotomies and consequent potential complications.

Split cerebral aqueduct: a neuroendoscopic illustration

PURPOSE

Forking of the cerebral aqueduct is a developmental malformation that is infrequently encountered by neurosurgeons as a rare cause of hydrocephalus, sometimes with a delayed onset. The etiology of an apparently forked aqueduct might be different. However, neuroendoscopy can often be the optimal treatment. The purpose of this study was to review the literature by analyzing the anatomical, functional, diagnostic, and therapeutic features of this unusual condition and adding our personal cases.

METHODS

We present a case of forking of the cerebral aqueduct that was detected in vivo and treated with a flexible scope. A thorough review of the pertinent literature is also discussed. In the past years, diagnosis of forked aqueduct was possible only postmortem.

RESULTS

A forked aqueduct is occasionally encountered in patients when a delayed hydrocephalic decompensation occurs.

CONCLUSIONS

Flexible neuroendoscopy enables for a direct, in vivo diagnosis and immediate treatment through a third ventriculostomy.

Banked Fascia Lata in Sellar Dura Reconstruction after Endoscopic Transsphenoidal Skull Base Surgery

Objectives Cerebrospinal fluid (CSF) leakage is an undesirable complication of transsphenoidal skull base surgery. The issue of the most appropriate sellar dura repair remains unresolved, although a multilayer technique using autologous fascia lata is widely used. We describe the novel application of a homologous banked fascia lata graft as an alternative to an autologous one in the reconstruction of sellar dura defects in endoscopic transsphenoidal surgery. Design The clinical records of patients who underwent endoscopic transsphenoidal surgery at our department from June 2012, when we started using homologous fascia lata, up to July 2014 were reviewed retrospectively. The data concerning diagnosis, reconstruction technique, and surgical outcome were analyzed. Results We treated 16 patients successfully with banked fascia lata. Twelve patients presented intraoperative CSF leakage, and four patients were treated for postoperative rhinoliquorrhea. Banked fascia lata was used in a single-to-multilayer technique, depending on the anatomical features of the defect and of the sellar floor. No complications or failures in sella reconstruction occurred. Conclusion A banked fascia lata graft proved reliable and safe in providing an effective sellar dura reconstruction. Used in a multilayer strategy, it should be considered a viable alternative to an autologous fascia lata graft.

The human area postrema: clear-cut silhouette and variations shown in vivo

OBJECT The human area postrema (AP) is a circumventricular organ that has only been described in cadaveric specimens and animals. Because of its position in the calamus scriptorius and the absence of surface markers on the floor of the fourth ventricle, the AP cannot be clearly localized during surgical procedures. METHODS The authors intravenously administered 500 mg fluorescein sodium to 25 patients during neuroendoscopic procedures; in 12 of these patients they explored the fourth ventricle. A flexible endoscope equipped with dual observation modes for both white light and fluorescence was used. The intraoperative fluorescent images were reviewed and compared with anatomical specimens and 3D reconstructions. RESULTS Because the blood-brain barrier does not cover the AP, it was visualized in all cases after fluorescein sodium injection. The AP is seen as 2 coupled leaves on the floor of the fourth ventricle, diverging from the canalis centralis medullaris upward. Although the leaves normally appear short and thick, there can be different morphological patterns. Exploration using the endoscope's fluorescent mode allowed precise localization of the AP in all cases. CONCLUSIONS Fluorescence-enhanced inspection of the fourth ventricle accurately identifies the position of the AP, which is an important landmark during surgical procedures on the brainstem. A better understanding of the AP can also be valuable for neurologists, considering its functional role in the regulation of homeostasis, emesis, and cardiovascular and electrolyte balance. Despite the limited number of cases in this report, evidence indicates that the normal anatomical appearance of the AP is that of 2 short and thick leaves that are joined at the midline. However, there can be great variability in terms of the structure's shape and size.

Peripheral trigeminal nerve field stimulation: report of 6 cases

OBJECT

Peripheral nerve field stimulation has been successfully used for many neuropathic syndromes. However, it has been reported as a treatment for trigeminal neuropathic pain or persistent idiopathic facial pain only in the recent years.

METHODS

The authors present a review of the literature and their own series of 6 patients who were treated with peripheral nerve stimulation for facial neuropathic pain, reporting excellent pain relief and subsequent better social relations and quality of life.

RESULTS

On average, pain scores in these patients decreased from 10 to 2.7 on the visual analog scale during a 17-month follow-up (range 0-32 months). The authors also observed the ability to decrease trigeminal pain with occipital nerve stimulation, clinically confirming the previously reported existence of a close anatomical connection between the trigeminal and occipital nerves (trigeminocervical nucleus).

CONCLUSIONS

Peripheral nerve field stimulation of the trigeminal and occipital nerves is a safe and effective treatment for trigeminal neuropathic pain and persistent idiopathic facial pain, when patients are strictly selected and electrodes are correctly placed under the hyperalgesia strip at the periphery of the allodynia region.

Third ventriculostomy site as a neuroreceptorial area

PURPOSE

Endoscopic third ventriculostomy is an established method for treating hydrocephalus. The third ventriculostomy site is considered a safe area that can be disrupted during surgical endoscopic procedures. The question of the clinical consequences of an apparently unavoidable injury to the floor of the third ventricle has been sporadically addressed in the literature. The aim of this study is to describe our anatomical and operative findings during endoscopic procedures performed in fluorescent mode after intravenous fluorescein injection and address the possible role of fluorescein-enhanced visualization of the median eminence as an accessory tool in order to partially spare this functional structure when performing ventriculostomy.

METHODS

We prospectively administered intravenously 500 mg of fluorescein sodium in 12 consecutive endoscopic surgery cases. A flexible scope equipped with dual observation modes for both white light and fluorescence was used. Taking into account the position of the basilar apex and the need for a conveniently sized stoma, a perforation area was chosen and dilated using a Fogarty balloon, guided by fluorescein-enhanced visualization of the median eminence.

RESULTS

After a mean of 20 s in the fluorescent mode, the fluorescein enhanced the visualization of the median eminence-tuber cinereum complex. In our preliminary experience, by opening the stoma in the fluorescence mode, almost half of the visible median eminence surface can be spared from iatrogenic sacrifice.

CONCLUSIONS

Tailoring fluorescence-guided ventriculostomy is a feasible way of trying to preserve the median eminence and may have implications for the site and safety of this common surgical procedure.

Anaplastic ependymoma of the third ventricle

Supratentorial ependymomas are rare, especially in the third ventricle. We report the case of an ependymoma of the posterior third ventricle that was endoscopically removed just by aspiration through a flexible scope. Histologically, beside the typical pattern of growth with perivascular pseudorosettes, the tumor featured hypercellular areas with more than 10 mitoses per 10 high-power fields, consistent with grade III-anaplastic tumor. A few months later, a second neuroendoscopy offered the unique chance to appreciate the total absence of tumor tissue and the restored anatomy. However, consistently with the high grade, the tumor recurred in two different locations including the endoscopic trajectory, and spread through the cerebrospinal fluid. The patient underwent a second resective surgery and radiosurgery. Despite a cycle of chemotherapy, multiple lesions both in the ventricular system and at the level of cauda equina appeared 12 months later. A comprehensive review of intraventricular anaplastic ependymomas is also provided.

The marionette technique for treatment of isolated fourth ventricle: technical note

Isolated fourth ventricle is not uncommon in complex posthemorrhagic or postinfectious hydrocephalus. When the condition is symptomatic, the current surgical treatment is endoscopic aqueductoplasty, followed by endoscope-assisted placement of a catheter in the fourth ventricle. The authors suggest a very simple method of steering the tip of standard ventricular catheters by using materials commonly available in all operating rooms. The main advantage of this method is that it permits less invasive transaqueductal drainage of trapped fourth ventricles, especially in cases of narrow third ventricle, because the scope and catheter are introduced in sequence and not in a double-barreled fashion. Two illustrative cases are reported.

Neuroendoscopic aspiration of tumors in the posterior third ventricle and aqueduct lumen: a technical update

BACKGROUND

Small soft ventricular tumors are good candidates for complete removal by a purely endoscopic technique. This approach is particularly interesting for lesions located in the posterior third ventricle and aqueductal lumen.

METHODS

We present our method of endoscospic aspiration through direct contact between the tumor and the working channel of a flexible scope.

RESULTS

Aspiration without the intermediate use of cannulas is safe and has proved to be effective in the apparently total or partial removal of three soft tumors of different pathologies located in the third ventricle or aqueductal lumen. In one case, a second neuroendoscopy a few months later to repeat endoscopic third ventriculostomy (ETV) offered a unique opportunity to observe the absence of the tumor and the restored anatomy.

CONCLUSIONS

Neuroendoscopy provides a safe, effective way to radically resect small soft tumors in these troublesome locations and can be a valuable alternative to microsurgery.

Gliomas of the pineal region

Although several series of pineal region tumors are available, the issue of pineal gliomas has been scarcely faced in the literature. Gliomas are usually included in largest series of pineal neoplasms. Therefore, whether pineal gliomas share the biological behavior of either hemispheric gliomas or other midline lesions is not yet defined. The aim of this retrospective study is to analyze long-term morbidity and mortality of these lesions. In English published literature gliomas account for about 14-22 % of all pineal region tumors. Most of these tumors are pilocytic astrocytomas, while glioblastoma multiforme is rare. We retrospectively analyzed all pineal region tumors operated on in our department in the last 28 years, and identified eight pineal astrocytomas, accounting for 14.03 % of all pineal tumors. The series includes four pilocytic astrocytomas, two grade II diffuse astrocytomas, and two anaplastic astrocytomas. A comprehensive review of the available literature data shows that the mean survival time of WHO grade II gliomas is shorter when tumor grows in the pineal region than for hemispheric locations, although the limited amount of available data prevents a rigorous statistical analysis. This difference might be due to the peculiar infiltrating behavior of pineal tumors, which often can't be satisfactorily resected from vital structures.

Fluorescein-Enhanced Characterization of Additional Anatomical Landmarks in Cerebral Ventricular Endoscopy

BACKGROUND:

Fluorescein enhancement to detect retinal disorder or differentiate cancer tissue in situ is a well-defined diagnostic procedure. It is a visible marker of where the blood-brain barrier is absent or disrupted. Little is reported in the contemporary literature on endoscopic fluorescein-enhanced visualization of the circumventricular organs, and the relevance of these structures as additional markers for safe ventricular endoscopic navigation remains an unexplored field.

OBJECTIVE:

To describe fluorescein sodium–enhanced visualization of circumventricular organs as additional anatomic landmarks during endoscopic ventricular surgery procedures.

METHODS:

We prospectively administered intravenously 500 mg fluorescein sodium in 12 consecutive endoscopic surgery patients. A flexible endoscope equipped with dual observation modes for both white light and fluorescence was used. During navigation from the lateral to the fourth ventricle, the endoscopic anatomic landmarks were first inspected under white light and then under the fluorescent mode.

RESULTS:

After a mean of 20 seconds in the fluorescent mode, the fluorescein enhanced visualization of the choroid plexus of the lateral ventricle, median eminence–tuber cinereum complex, organum vasculosum of the lamina terminalis, choroid plexus of the third and fourth ventricles, and area postrema.

CONCLUSION:

Fluorescein-enhanced visualization is a useful tool for helping neuroendoscopists recognize endoscopic anatomic landmarks. It could be adopted to guide orientation when the surgeon deems an endoscopic procedure unsafe or contraindicated because of unclear or subverted anatomic landmarks. Visualization of the circumventricular organs could add new insight into the functional anatomy of these structures, with possible implications for the site and safety of third ventriculostomy.

External ventricular drainage alone versus endoscopic surgery for severe intraventricular hemorrhage: a comparative retrospective analysis on outcome and shunt dependency

OBJECT

Massive intraventricular hemorrhages (IVHs) require aggressive and rapid management to decrease intracranial hypertension, because the amount of intraventricular blood is a strong negative prognostic predictor on outcome. Neuroendoscopy may offer some advantages over more traditional surgical approaches on outcome and may decrease the number of shunt procedures that need to be performed.

METHODS

The authors retrospectively reviewed the clinical and radiological data in 96 patients treated for massive IVH who were admitted between January 1996 and June 2008 to the neurosurgery unit after undergoing emergency CT scanning. Forty-eight patients (Group A) were treated with endoscopic aspiration surgery using a flexible endoscope with a "freehand" technique. A historical group of 48 patients (Group B) treated using external ventricular drain (EVD) placement alone was used as a comparison. The authors compared the radiological results with the clinical outcomes at 1 year according to the modified Rankin Scale and the need for internal CSF shunt treatment in the 2 groups.

RESULTS

Endoscopic aspiration did not significantly affect the outcome at 1 year as determined using the modified Rankin Scale. Patients who underwent endoscopy had an EVD in place for 0.18 days fewer than patients treated with an EVD alone. Patients undergoing external ventricular drainage alone had a 5 times greater chance of requiring a shunting procedure than those treated using neuroendoscopy and external ventricular drainage. Neuroendoscopy plus external drainage reduces shunting rates by 34% when compared with external drainage alone.

CONCLUSIONS

The reduction in internal shunt surgery encourages the adoption of neuroendoscopic aspiration of severe IVH as a therapeutic tool to decrease shunt dependency.

Endoscopic management of intracerebral hemorrhage

OBJECTIVES

Massive intracerebral and intraventricular hemorrhages require aggressive and rapid management to decrease intracranial hypertension. The amount of intraventricular blood is a strong prognostic predictor, and its fast removal is a priority. Neuroendoscopy may offer some advantages over more traditional surgical approaches.

METHODS

All relevant data described in our experience and in publications about minimally invasive treatment of intraventricular and intracerebral hemorrhage found through MEDLINE searches and related references are reviewed.

RESULTS

We described the technical details of neuroendoscopic management, highlighting the potential pitfalls and advantages of the techniques.

CONCLUSION

Early neuroendoscopic surgery is a feasible approach, allowing, in most instances, rapid clinical and radiological improvement.

Spontaneous resolution of atraumatic intrauterine ping-pong fractures in newborns delivered by cesarean section

Two cases of spontaneous intrauterine ping-pong fractures are reported in newborns delivered by cesarean section. Skull fractures occurred with no evidence of extrinsic trauma or cephalopelvic disproportion. Subsequent clinical follow-up at 6 and 12 months revealed normal skull reshaping and growth, with no associated neurological deficits. Spontaneous intrauterine ping-pong fractures in newborns delivered by cesarean section is a distinctly rare condition. These 2 cases demonstrate that, even without complicated spontaneous vaginal delivery or history of external trauma, congenital ping-pong fracture of the skull can occur. The existence of this clinical condition and its spontaneous resolution is important knowledge that can assist in the prepartum and postpartum management of children with this pathology.

Neuroendoscopic biopsy of ventricular tumors: a multicentric experience

OBJECT

Although neuroendoscopic biopsy is routinely performed, the safety and validity of this procedure has been studied only in small numbers of patients in single-center reports. The Section of Neuroendoscopy of the Italian Neurosurgical Society invited some of its members to review their own experience, gathering a sufficient number of cases for a wide analysis.

METHODS

Retrospective data were collected by 7 centers routinely performing neuroendoscopic biopsies over a period of 10 years. Sixty patients with newly diagnosed intraventricular and paraventricular tumors were included. No patient harboring a colloid cyst was included. Data regarding clinical presentation, neuroimaging findings, operative techniques, pathological diagnosis, postoperative complications, and subsequent therapy were analyzed.

RESULTS

In all patients, a neuroendoscopic tumor biopsy was performed. In 38 patients (64%), obstructive hydrocephalus was present. In addition to the tumor biopsy, 32 patients (53%) underwent endoscopic third ventriculostomy (ETV), and 7 (12%) underwent septum pellucidotomy. Only 2 patients required a ventriculoperitoneal shunt shortly after the endoscopy procedure because ETV was not feasible. The major complication due to the endoscopy procedure was ventricular hemorrhage noted on the postoperative images in 8 cases (13%). Only 2 patients were symptomatic and required medical therapy. Infection occurred in only 1 case, and the other complications were all reversible. In no case did clinically significant sequelae affect the patient's outcome. Tumor types ranged across the spectrum and included glioma (low- and high-grade [27%]), pure germinoma (15%), pineal parenchymal tumor (12%), primary neuroectodermal tumor (4%), lymphoma (9%), metastasis (4%), craniopharyngioma (6%), and other tumor types (13%). In 10% of patients, the pathological findings were inconclusive. According to diagnosis, specific therapy was performed in 35% of patients: 17% underwent microsurgical removal, and 18% underwent chemotherapy or radiotherapy.

CONCLUSIONS

This is one of the largest series confirming the safety and validity of the neuroendoscopic biopsy procedure. Complications were relatively low (about 13%), and they were all reversible. Neuroendoscopic biopsy provided meaningful pathological data in 90% of patients, making subsequent tumor therapy feasible. Cerebrospinal fluid pathways can be restored by ETV or septum pellucidotomy (65%) to control intracranial hypertension. In light of the results obtained, a neuroendoscopic biopsy should be considered a possible alternative to the stereotactic biopsy in the diagnosis and treatment of ventricular or paraventricular tumors. Furthermore, it could be the only surgical procedure necessary for the treatment of selected tumors.

Dynamic monitors of brain function: a new target in neurointensive care unit

Introduction

Somatosensory evoked potential (SEP) recordings and continuous electroencephalography (EEG) are important tools with which to predict Glasgow Outcome Scale (GOS) scores. Their combined use may potentially allow for early detection of neurological impairment and more effective treatment of clinical deterioration.

Methods

We followed up 68 selected comatose patients between 2007 and 2009 who had been admitted to the Neurosurgical Intensive Care Unit of Treviso Hospital after being diagnosed with subarachnoid haemorrhage (51 cases) or intracerebral haemorrhage (17 cases). Quantitative brain function monitoring was carried out using a remote EEG-SEP recording system connected to a small amplification head box with 28 channels and a multimodal stimulator (NEMO; EBNeuro, Italy NeMus 2; EBNeuro S.p.A., Via P. Fanfani 97/A - 50127 Firenze, Italy). For statistical analysis, we fit a binary logistic regression model to estimate the effect of brain function monitoring on the probability of GOS scores equal to 1. We also designed a proportional odds model for GOS scores, depending on amplitude and changes in both SEPs and EEG as well as on the joint effect of other related variables. Both families of models, logistic regression analysis and proportional odds ratios, were fit by using a maximum likelihood test and the partial effect of each variable was assessed by using a likelihood ratio test.

Results

Using the logistic regression model, we observed that progressive deterioration on the basis of EEG was associated with an increased risk of dying by almost 24% compared to patients whose condition did not worsen according to EEG. SEP decreases were also significant; for patients with worsening SEPs, the odds of dying increased to approximately 32%. In the proportional odds model, only modifications of Modified Glasgow Coma Scale scores and SEPs during hospitalisation statistically significantly predicted GOS scores. Patients whose SEPs worsened during the last time interval had an approximately 17 times greater probability of a poor GOS score compared to the other patients.

Conclusions

The combined use of SEPs and continuous EEG monitoring is a unique example of dynamic brain monitoring. The temporal variation of these two parameters evaluated by continuous monitoring can establish whether the treatments used for patients receiving neurocritical care are properly tailored to the neurological changes induced by the lesions responsible for secondary damage.

Endoscopic third ventriculostomy in previously shunted children: a retrospective study

PURPOSE

The aim of this study was to assess the mid-term results, success rates, and time-to-failure of secondary endoscopic third ventriculostomy (secondary ETV), as well as the complex management of preoperative and postoperative cares.

METHODS

To this purpose, a retrospective analysis of a pediatric population of 22 children who underwent endoscopic third ventriculostomy (ETV) after shunt malfunction (secondary ETV) was performed.

RESULTS

The failure rate, given by the percentage of new shunt replacement in the first 3 months after ETV, was 36%, with a mean time to failure of 14.3 days. All the failures were evident within 1 month after the ETV. Despite the small number of patients in our series, we found no significant correlation between ETV failure and both patient age and hydrocephalus etiology (p = 0.47 and p = 0.78, respectively).

CONCLUSIONS

In our experience, ETV secondary to shunt malfunction in pediatric patients has a success rate of 64%. As it is a safe and rapid treatment option even in emergency conditions, it is worth performing this procedure in previously shunted children.

Amaurosis in infancy due to craniopharyngioma: a not-exceptional but often misdiagnosed symptom

Since children may not be able to complain of progressive reduction in optic acuity, visual assessment in infancy may present practical difficulties. The authors report a case of craniopharyngioma, which led a young child to early blindness before the correct diagnosis could be made. Similar to other reported cases, the authors found that surgery did not substantially modify the preoperative visual deficit. They conclude that minimal improvement in visual acuity can be expected despite successful microsurgical removal of the tumor.

Microembolic signals and strategy to prevent gas embolism during extracorporeal membrane oxygenation

Background

Extracorporeal membrane oxygenation (ECMO) supplies systemic blood perfusion and gas exchange in patients with cardiopulmonary failure. The current literature lacks of papers reporting the possible risks of microembolism among the complications of this treatment.

In this study we present our preliminary experience on brain blood flow velocity and emboli detection through the transcranial Doppler monitoring during ECMO.

Methods

Six patients suffering of heart failure, four after cardiac surgery and two after cardiopulmonary resuscitation were treated with ECMO and submitted to transcranial doppler monitoring to accomplish the neurophysiological evaluation for coma.

Four patients had a full extracorporeal flow supply while in the remaining two patients the support was maintained 50% in respect to normal demand.

All patients had a bilateral transcranial brain blood flow monitoring for 15 minutes during the first clinical evaluation.

Results

Microembolic signals were detected only in patients with the full extracorporeal blood flow supply due to air embolism.

Conclusions

We established that the microembolic load depends on gas embolism from the central venous lines and on the level of blood flow assistance.

The gas microemboli that enter in the blood circulation and in the extracorporeal circuits are not removed by the membrane oxygenator filter.

Maximum care is required in drugs and fluid infusion of this kind of patients as a possible source of microemboli. This harmful phenomenon may be overcome adding an air filter device to the intravenous catheters.

PRIMARY OBSTRUCTION OF THE FOURTH VENTRICLE OUTLETS

OBJECTIVE

Primary obstruction of the foramina of Magendie and Luschka is an uncommon and still unclear cause of noncommunicating hydrocephalus. The aim of this work is the description, for the first time, of the inner aspect of these velar obstructions of the fourth ventricle outlets and the demonstration of the efficacy of neuroendoscopic treatment.

METHODS

Of 240 hydrocephalic patients treated in our institution with endoscopic third ventriculostomy, a subgroup of 10 cases with closure of the fourth ventricular outlets without associated Chiari malformation and syringomyelia was selected. In all of these cases, a transaqueductal endoscopic navigation of the fourth ventricle was performed, and the obstructed outlets were inspected. All of the clinical data and, in particular, the videotape records of endoscopic operations, as well as the cine-magnetic resonance imaging scans, were reviewed to evaluate their patency status.

RESULTS

Various degrees of stenosis were found endoscopically: restriction of the Magendie contour with thick and opaque membrane, transparent spider web-like membrane, and dense membrane with fissures acting as valves. Endoscopic third ventriculostomy was effective in almost all patients, although we noticed an unforeseen high incidence of closure of the stoma. The restored normal cerebrospinal fluid flux after ventriculocisternostomy and magendieplasty was demonstrated by comparative study of cerebrospinal fluid flow measurements by cine-magnetic resonance imaging.

CONCLUSION

This report demonstrates the effectiveness of neuroendoscopic third ventriculostomy as well as magendiestomy in cases of tetraventricular hydrocephalus attributable to primary obstruction of the outlets of the fourth ventricle and, for the first time, presents direct images of various types of outlet obstructive pathology.