A review of solitary fibrous tumor/hemangiopericytoma tumor and a comparison of risk factors for recurrence, metastases, and death among patients with spinal and intracranial tumors.

Meningeal solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) had been combined into a single classification until 2016. Recurrence and metastases rates are still understudied, especially for spinal SFT/HPCs. Here, we describe CNS SFT/HPCs and predictors for recurrence, metastases, and death, in spinal and intracranial SFT/HPCs, separately. We collected data from studies with patient-level data available on primary SFT/HPCs from multiple online databases. Clinico-demographic data, surgical outcomes, recurrence, metastases, and death rates were abstracted. We used logistic and Cox regression models to identify predictors for recurrence, metastases, and death for spinal and intracranial SFT/HPCs. Twenty-nine studies (368 patients) were included. Higher histological grade and subtotal resection were associated with recurrence (p values < 0.05), while higher histological grade and recurrence (p values < 0.005) were associated with metastases formation. Time to recurrence (p < 0.005) and metastases (p < 0.001) formation were shorter for spinal SFT/HPCs. Death rates were higher among intracranial SFT/HPC patients (p value = 0.001). Among patients with higher histological grade, rates of metastases formation were different between intracranial and spinal SFT/HPCs. Risk of metastases was higher in the first 5 years from surgery for both intracranial and spinal SFT/HPCs. Meningeal SFT/HPCs patients have high rates of recurrence and metastasis, which occur mostly within the first 5 years after diagnosis. Spinal and intracranial SFT/HPCs show similar behavior, but spinal SFT/HPCs tend to develop metastases and recurrences in a shorter interval of time. Careful follow-up for spinal SFT/HPCs should be considered because spinal cases seem to be slightly more aggressive and require more attention.

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.

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.

Carbon dioxide field flooding reduces the hemodynamic effects of venous air embolism occurring in the sitting position.

PURPOSE: Although the utility of the sitting position is undisputed for biomechanical and ergonomic reasons, it has been debated in recent years for its risks, particularly venous air embolism (VAE). In order to reduce the hemodynamic effect of VAE, we changed the composition of the surgical field air partially replacing nitrogen with carbon dioxide (CO2) that better dissolves in human tissues. METHODS: First, we tested our method on a test dummy in the sitting position. Infrared CO2 sensors were placed close to the wound opening and on the facial mask of the surgeon. An oxygen sensor was connected to a computer for data recording (ALTAIR(®), MSA Safety). This model showed that 10 L/min CO2 flow provides efficient air displacement, maintaining safety for the surgeon. We reproduced the above-described surgical field environment in ten consecutive cases of posterior fossa surgery performed in the sitting position. A homogeneous group of ten patients operated in the sitting position with standard setting environment was used for control. We intraoperatively monitored VAE with trans-esophageal echocardiography (TEE), end-tidal CO2 (ETCO2), CO2 arterial pressure (PaCO2), and hemodynamic changes. RESULTS: Although the percentage of VAE was 70% in both groups, hemodynamic effects occurred in 10% of cases in the study group and in 40% of cases in the control group. CONCLUSIONS: Our preliminary study shows that a CO2-enriched sitting position surgical microenvironment significantly reduces the hemodynamic effects of VAE, more likely because arterial CO2 emboli are more soluble and consequently much better tolerated than air emboli.

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.

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.

The Correlation Between Paraspinal Muscular Morphology, Spinopelvic Parameters, and Back Pain: A Comparative Cohort Study.

BACKGROUND: The relationship between paraspinal muscle degeneration and low back pain (LBP), disability, and structural changes has been investigated in the literature, but it is still a matter of debate. We differentiated paraspinal muscle magnetic resonance imaging by quality and quantity, focusing on fatty infiltration (FI) and paraspinal muscles cross-sectional area (CSA) from T12 to S1 in patients with and without chronic LBP. We aimed to determine whether paraspinal muscle quantity (CSA) and quality (FI) are positively associated with LBP or degenerative/spinopelvic changes in the spine. METHODS: Between 2018 and 2021, we prospectively enrolled 205 patients aged between 18 to 65 years, of whom 153 patients had chronic back pain (back pain group) and 52 patients did not have chronic back pain (no back pain group), and collected clinicodemographic, structural, and spinopelvic data. We correlated these data with paraspinal muscle FI and CSA from T12 to S1. Multivariate models were run to highlight associations between pain, disability, or degenerative and spinopelvic parameters. RESULTS: Age was not associated with increased FI but consistently with decreased CSA values. After adjusting for age, sex, and body mass index, FI was associated with an increased risk of back pain (OR, 8.80; 95% CI, 1.9-39.79; P = 0.006) and high disability scores (OR, 3.41; 95% CI, 1.12-10.30; P = 0.030). Decreased CSA was associated with reduced disc height (P < 0.001), while FI and CSA did not associate with abnormal spinopelvic parameters. CONCLUSIONS: FI on paraspinal muscle highly correlates with back pain and disability but was not found in structural and degenerative changes in the lower back. CLINICAL RELEVANCE: Findings from this study are clinically relevant for patient counseling and rehabilitation strategies. LEVEL OF EVIDENCE: 2b.

The extent of resection of T2-flair hyperintense area for eloquent glioblastomas: outcomes analysis between awake and general anesthesia patients.

BACKGROUND: Maximum safe resection for eloquent areas glioblastomas (GBMs) is the greatest tumor resection achievable without causing neurological deficits. This study aims to assess, through quantitative volumetric analysis, the outcomes of patients with eloquent areas GBMs and correlate the extent of resection (EOR), based on MRI T1-contrast enhanced (CE) and T2- fluid-attenuated inversion recovery (FLAIR) sequences, with patient outcomes and overall survival. METHODS: We prospectively collected and analyzed patients with a diagnosis of primary GBM located in an eloquent area operated between January 2012 and April 2018. We examined 295 consecutive patients' records with GBM and identified 82 eloquent GBMs who met inclusion criteria. We stratified our patients by type of treatment-awake surgery (AS) and general anesthesia (GA) craniotomies. The kind of treatment was correlated with EOR, focusing on exeresis over the limit of the contrast-enhanced signal intensity, including both T1-CE and T2-FLAIR MRI signal alterations. RESULTS: The overall mean EOR value was higher in AS than in GA on T1-CE (P value: 0.010) and T2-Flair MRI images (P value: 0.007). Also, patients who had at least 30% of T2-FLAIR signal resection (EOR≥30%) had a significantly lower risk of death and recurrence (P value: 0.020), independent of residual T1-CE tumor volume. CONCLUSIONS: Extensive T2-Flair resection and AS improve overall survival and reduce risk of recurrence while simultaneously minimizing surgical and medical complications among patients with GBMs in eloquent areas.

Bibliographic Study and Meta-Analysis of Clinical Outcomes of Full-Endoscopic Spine Surgery for Painful Lumbar Spine Conditions.

BACKGROUND: Full-endoscopic spine surgery (FESS) indications already cover degenerative, infectious, and neoplastic diseases. This study aimed to use a bibliometric search and meta-analysis of the highest-quality studies in the last 20 years to determine the quantity and quality of FESS research, geographic distribution, and the outcomes for lumbar conditions. METHODS: Articles on FESS published from 2000 to 2022 were screened and assessed through Web of Science, PubMed, and Scopus. Also, databases were searched for longitudinal studies to pool in a meta-analysis of patients undergoing FESS for lumbar conditions. After stratifying the risk of bias and having collected the studies of the highest quality, we included the proportion of patients with a satisfactory outcome and intraoperative and postoperative adverse events after the analysis of lumbar spine conditions. RESULTS: A total of 728 articles were identified by the bibliographic search. Between 2000 and 2021, the published articles increased 21-fold. Most were from China (70.15%), followed by South Korea (19.5%). Most were retrospective (68.3%) and regarding treatment of lumbar disease (86.4%). Fifty studies, including 34,828 patients, were pooled in the meta-analysis. More than 85% of patients experienced satisfactory improvement in each of different lumbar conditions. Major adverse events were <2%; recurrence and postoperative dysesthesia rates were within those reported for open or mini-invasive procedures. CONCLUSIONS: This study may fill research gaps on FESS and lead to adequately designed studies. Our meta-analysis showed that FESS for lumbar diseases is a procedure with satisfactory outcomes and low rates of adverse events.

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.

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.

A Systematic Review and Meta-Analysis of Outcomes and Adverse Events for Juxtafacet Cysts Treatment.

BACKGROUND: Different procedures have been used for the treatment of lumbar juxtafacet cysts (JFCs). Recently, full-endoscopic cyst excision has been suggested as a reasonable alternative. We performed a meta-analysis to assess the overall rates of favorable outcomes and adverse events for each available treatment and determine the outcome and complication rates concerning spine stability. METHODS: Multiple databases were searched for English-language studies involving adult patients with lumbar JFCs who had been followed for more than 6 months. Outcomes included the proportion of patients with a satisfactory outcome. Adverse events included recurrence and revision rates as well as intraoperative complications. We further stratified the analysis based on the spine's condition (degenerative listhesis vs without degenerative listhesis). RESULTS: A total of 43 studies, including 2226 patients, were identified. Over 80% of patients experienced satisfactory improvement after surgical excision but only 66.2% after percutaneous cyst rupture and aspiration. Overall, recurrence and revision rates were almost double in patients with preoperative degenerative listhesis at the cyst level, especially in the minimally invasive group (2.1% vs 31.3% and 6.8% vs 13.1%, respectively). The rate of full-endoscopic satisfactory outcomes was approximately 90%, with low rates of adverse events (<2%). CONCLUSION: We analyzed the outcome and adverse event rates for each kind of available treatment for JFC. Full endoscopy has outcomes and rates of adverse events that overlap with open and minimally invasive approaches. LEVEL OF EVIDENCE: 2A.

Treatment of thoracolumbar burst fractures: SpineJack vs. posterior arthrodesis-comparison of clinical and radiological outcomes.

Background: Thoracolumbar fractures sometimes require anterior support and post-traumatic deformity correction. SpineJack proved favorable results in cadaveric and clinical studies, with satisfactory pain relief, vertebral height restoration, and low rates of above adjacent fractures, in neurologically intact fractures. We compared patients' clinical and radiological outcomes of thoracolumbar fractures treated either with posterior arthrodesis or SpineJack. Methods: We prospectively collected A2 split and A3, and A4 burst fractures between 2017 and 2021. Patients were stratified in posterior arthrodesis (PA group) and SpineJack (SJ group) and included if age ≥18 years, T11-L3 level, emergent or elective surgery, single or multiple, and neurologically intact. Age, sex, type and level, pain, operative and discharge time, vertebral body heights (VBH), posterior wall retropulsion (PWR), vertebral kyphosis (VK) and local kyphosis (LK) angles, vertebral body (VB) volume, and complications were collected. We then compared clinical-radiographic outcomes between the two groups. Results: We found no significant differences in median postoperative pain while operative time and discharge time were shorter for SJ patients than PA ones (P<0.001). Mean anterior VBH increase was 20.7%, mid-VBH was 25.5%, and posterior VBH was 8.8%, while increase in VB volume was 26.2%. SJ patients had non-inferior VK e LK angles correction to PA ones. Mean PWR value between pre and post SJ implantation was 0.15±0.65 mm, and no adjacent above-level fractures occurred. Conclusions: We showed satisfactory outcomes in a selected range of neurologically intact thoracolumbar split or burst fractures. SJ leads to shorter operative and discharge time and good VB angles and diameters restoration.

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.

Primary and metastatic intraaxial brain tumors: prospective comparison of multivoxel 2D chemical-shift imaging (CSI) proton MR spectroscopy, perfusion MRI, and histopathological findings in a group of 159 patients.

BACKGROUND: This study aims to assess the diagnostic value of multivoxel 2D chemical-shift imaging (CSI) proton magnetic resonance (MR) spectroscopy combined with perfusion magnetic resonance imaging (MRI) in the differential diagnosis and grading of brain tumors by comparing neuroimaging data with histopathological findings obtained after resection or biopsy. METHODS: A total of 159 patients with a previous brain tumor diagnosis underwent multivoxel 2D CSI proton MR spectroscopy and perfusion MRI. MR spectroscopy multivoxel 2D CSI was performed with an echo time of 30, TR 1,500, FOV 160 mm, acquisition time 7 min 34 s. rCBV maps were evaluated during postprocessing. Statistical analysis was performed on the examination of distributive normality, with logarithmic transformations, Fisher's test, and Bonferroni's test. We used the Pearson's test to compare percentages. RESULTS: In the differential diagnosis between GBM and metastases, MR spectroscopy multivoxel 2D CSI, combined with dynamic contrast enhanced MRI (DCE-MRI) perfusion, reached high sensibility and specificity (p < 0.000001). In brain tumor grading, the same method reached high sensibility and specificity (p < 0.000001) in distinguishing grade III-IV gliomas but encountered difficulty in determining grades within the two main groups of primary brain tumors, especially where mixed gliomas were involved. CONCLUSIONS: The systematic use of CSI spectroscopy and perfusion imaging has shown a high potential in the differential diagnosis and grading of brain tumors. Further exploration into diagnostic procedures that can significantly distinguish between grade III-IV and grade II tumors is needed.

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.

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.

Pituitary metastasis of Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a malignant neuroendocrine tumor of the skin that demonstrates a remarkable tendency to metastasize. However, only a few cases of MCC brain metastases have been reported in the literature. We here present a unique case of a pituitary metastasis of MCC in a 65-year-old patient with a history of pituitary adenoma. This case is particularly novel due to the fact that the primary site of the MCC is unknown.

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.