Plectin plays a role in the migration and volume regulation of astrocytes: a potential biomarker of glioblastoma.

BACKGROUND: The expression of aquaporin 4 (AQP4) and intermediate filament (IF) proteins is altered in malignant glioblastoma (GBM), yet the expression of the major IF-based cytolinker, plectin (PLEC), and its contribution to GBM migration and invasiveness, are unknown. Here, we assessed the contribution of plectin in affecting the distribution of plasmalemmal AQP4 aggregates, migratory properties, and regulation of cell volume in astrocytes. METHODS: In human GBM, the expression of glial fibrillary acidic protein (GFAP), AQP4 and PLEC transcripts was analyzed using publicly available datasets, and the colocalization of PLEC with AQP4 and with GFAP was determined by immunohistochemistry. We performed experiments on wild-type and plectin-deficient primary and immortalized mouse astrocytes, human astrocytes and permanent cell lines (U-251 MG and T98G) derived from a human malignant GBM. The expression of plectin isoforms in mouse astrocytes was assessed by quantitative real-time PCR. Transfection, immunolabeling and confocal microscopy were used to assess plectin-induced alterations in the distribution of the cytoskeleton, the influence of plectin and its isoforms on the abundance and size of plasmalemmal AQP4 aggregates, and the presence of plectin at the plasma membrane. The release of plectin from cells was measured by ELISA. The migration and dynamics of cell volume regulation of immortalized astrocytes were assessed by the wound-healing assay and calcein labeling, respectively. RESULTS: A positive correlation was found between plectin and AQP4 at the level of gene expression and protein localization in tumorous brain samples. Deficiency of plectin led to a decrease in the abundance and size of plasmalemmal AQP4 aggregates and altered distribution and bundling of the cytoskeleton. Astrocytes predominantly expressed P1c, P1e, and P1g plectin isoforms. The predominant plectin isoform associated with plasmalemmal AQP4 aggregates was P1c, which also affected the mobility of astrocytes most prominently. In the absence of plectin, the collective migration of astrocytes was impaired and the dynamics of cytoplasmic volume changes in peripheral cell regions decreased. Plectin's abundance on the plasma membrane surface and its release from cells were increased in the GBM cell lines. CONCLUSIONS: Plectin affects cellular properties that contribute to the pathology of GBM. The observed increase in both cell surface and released plectin levels represents a potential biomarker and therapeutic target in the diagnostics and treatment of GBMs.

Image-Guided Surgery in Complex Skull Base and Facial Fractures: Initial Experience on the Role of Intra-Operative Computer Tomography.

Surgery of fractures involving the skull base and the facial skeleton often presents challenges that should be addressed to prevent secondary brain injuries (i.e., cerebro-spinal fluid leak), preserve visual functioning, and guarantee a good esthetic result. Complex craniofacial reconstruction can be aided by navigation and pre-operative planning. In recent years, computerized planning of surgical reconstruction drastically increased the safety and efficacy of surgery, but the impact of intraoperative high quality image devices such as an intraoperative computed tomography (CT) scan has not been investigated yet. This case-control study reports the institutional preliminary experience of using intraoperative CT scans in the surgical management of complex cranio-facial fractures. The results in terms of accuracy of bony reconstruction and neurological or surgical complications have been analyzed in 12 consecutive patients treated with (6 cases) or without (6 cases) i-CT. Comparative analysis demonstrated a greater accuracy of reconstruction in patients treated with the assistance of i-CT. Intraoperative CT is a useful tool with a promising role in a multidisciplinary surgical approach to complex cranio-facial surgery.

Hybrid Implants in Anterior Cervical Spine Surgery: The State of the Art and New Trends for Multilevel Degenerative Disc Disease.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) still represents the first surgical option in the treatment of cervical degenerative disc disease (DDD) but is still burdened by several complications secondary to the loss of mobility at the treated segment and adjacent segment diseases (ASDs). To overcome those complications, hybrid surgery (HS) incorporating ACDF and cervical disc arthroplasty (CDA) is increasingly performed for DDD. METHODS: We retrospectively reviewed the clinical, surgical, and outcome data of 85 consecutive patients (M/F, 41/44) harboring cervical disc herniation with or without osteophytes, with radiculopathy and with or without myelopathy, who underwent the anterior approach to a cervical discectomy on two or more levels with at least one disc prosthesis, along with a cage and plate or an O Profile screwed plate. RESULTS: All the patients improved regardless of the cervical construct used. No significant relationship between different kinds of prosthesis and their surgical level; the number of cages; and the site of the cages (screwed and/or plated) was found concerning immediate stability, dynamic prosthesis effectiveness, and clinical improvement in all the patients up to the maximum follow-up time. CONCLUSIONS: Although the optimal surgical technique for cervical DDD remains controversial, HS represents a safe and effective procedure in select patients with multilevel cervical DDD, as demonstrated by biomechanical and clinical studies and the present series.

Direct Transpedicular C2 Fixation for the Surgical Management of Hangman's Fractures: A "Second Youth" for the Judet Approach.

PURPOSE: The optimal management of hangman's fractures is controversial and the standard of care has been neither established nor supported by strong evidence. The Judet approach has been introduced in 1970 as surgical option to treat selected cases of hangman's fractures, harboring the advantage to preserve motion of the craniovertebral junction and to restore the C2 vertebra anatomy by insertion of transpedicular screws through the fracture line. This paper reviews the literature on hangman's fractures surgically managed by Judet approach, and reports two new illustrative cases. METHODS: The PubMed database was searched for the review process. After initial screening of abstracts and papers, 13 manuscripts were included in the present review.Two cases of hangman's fractures, a Levine-Edwards type I and a type IIA, respectively, treated with direct transpedicular C2 screw fixation are reported. Surgical steps of the Judet approach are also described. RESULTS: Our literature review revealed that the technique described by Judet is gaining appeal only in recent years and there is no consensus on surgical indications.No surgery-related complications were observed in the two reported cases. Patients experienced a significant reduction of neck pain postoperatively. Motion of craniovertebral junction was preserved in both patients at 3-, 6-, and 12-month follow-ups. CONCLUSIONS: Direct transpedicular osteosynthesis of C2-pars interarticularis fracture has been already demonstrated as effective in type II and IIA hangman's fractures. The application of such technique in selected patients with atypical type I fractures should also be considered in order to achieve early mobilization and avoid external fixation.

Role of i-CT, i-US, and Neuromonitoring in Surgical Management of Brain Cavernous Malformations and Arteriovenous Malformations: A Case Series.

OBJECTIVE: We retrospectively reviewed the institutional experience in patients who underwent microsurgical resection of cavernous malformations (CMs) or arteriovenous malformations (AVMs) using a multimodal intraoperative protocol including neuronavigation, intraoperative ultrasound (i-US), computed tomography (i-CT), and neuromonitoring. METHODS: Twenty-four patients (14 male), with a mean age of 47.5 years (range 27-73), have been included: 20 of them suffered from CMs and 4 suffered from AVMs. Neuromonitoring was used in 18 cases, when lesions were located in eloquent areas; 2 patients underwent awake craniotomy. First, an i-CT scan with and without contrast was acquired after patient positioning. Navigated B-mode ultrasound acquisition was carried out after dural opening to identify the lesion (CMs or AVMs nidus). Following identification and resection of vascular lesions, postcontrast i-CT (or CT-angio) was performed to detect and localize any small or calcified remnant (in cases of CMs) or residual vessels feeding the nidus (in cases of AVMs). RESULTS: In 5 cases of CMs and in 1 case of AVM, i-CT identified small residual lesions. In these cases, new i-CT images were uploaded into the navigation system and used for further resection. i-US was useful before starting transsulcal or transcortical approach to identify the lesions and guide the trajectory of the approach. However, several artifacts were observed during subsequent steps of dissection, making image interpretation difficult. CONCLUSIONS: The combination of different intraoperative real-time imaging modalities (i-CT and i-US), coupled with neuromonitoring, in the surgical management of vascular lesions, particularly if located in eloquent areas, has a positive impact on clinical outcome.

Hybrid implants in anterior cervical decompressive surgery for degenerative disease.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) still represent the mainstream surgical approach in the treatment of degenerative cervical Degenerative Disc Disease (DDD), being a loss of mobility at the treated segment and adjacent segment diseases well-known complications. To overcome those complications, hybrid surgery (HS) incorporating ACDF and cervical disk arthroplasty is increasingly performed for DDD. METHODS: We retrospectively reviewed the clinical, surgical, and outcome data of 62 consecutive patients (male/female, 29/37) harboring cervical disk herniation with or without osteophytes, with radiculopathy with or without myelopathy, who underwent a cervical discectomy on two or more levels with the anterior approach with at least one disk prosthesis along with cage and plate or O Profile screwed plate. RESULTS: All the patients improved regardless of the cervical construct used. No significant relationship between different kind of prostheses as well as their surgical level, the number and the site of the cages (screwed and/or plated) was found out concerning immediate stability, dynamic prosthesis effectiveness, and clinical improvement in all the patients up to the maximum follow-up. CONCLUSIONS: Although the optimal surgical technique for cervical DDD remains controversial, HS represents a safe and effective procedure in selected patients with multilevel cervical DDD, as demonstrated by biomechanical and clinical studies and the present series. Some technical aspects should be considered when dealing with this procedure, like the drilling of the endplate, and some radiological findings have to be detected because potentially predictive of future misplacement.

FLAIRectomy in Supramarginal Resection of Glioblastoma Correlates With Clinical Outcome and Survival Analysis: A Prospective, Single Institution, Case Series.

BACKGROUND: Extent of tumor resection (EOTR) in glioblastoma surgery plays an important role in improving survival. OBJECTIVE: To analyze the efficacy, safety and reliability of fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) images used to guide glioblastoma resection (FLAIRectomy) and to volumetrically measure postoperative EOTR, which was correlated with clinical outcome and survival. METHODS: A total of 68 glioblastoma patients (29 males, mean age 65.8) were prospectively enrolled. Hyperintense areas on FLAIR images, surrounding gadolinium-enhancing tissue on T1-weighted MR images, were screened for signal changes suggesting tumor infiltration and evaluated for supramaximal resection. The surgical protocol included 5-aminolevulinic acid (5-ALA) fluorescence, neuromonitoring, and intraoperative imaging tools. 5-ALA fluorescence intensity was analyzed and matched with the different sites on navigated MR, both on postcontrast T1-weighted and FLAIR images. Volumetric evaluation of EOTR on T1-weighted and FLAIR sequences was compared. RESULTS: FLAIR MR volumetric evaluation documented larger tumor volume than that assessed on contrast-enhancing T1 MR (72.6 vs 54.9 cc); residual tumor was seen in 43 patients; postcontrast T1 MR volumetric analysis showed complete resection in 64 cases. O6-methylguanine-DNA methyltransferase promoter was methylated in 8/68 (11.7%) cases; wild type Isocytrate Dehydrogenase-1 (IDH-1) was found in 66/68 patients. Progression free survival and overall survival (PFS and OS) were 17.43 and 25.11 mo, respectively. Multiple regression analysis showed a significant correlation between EOTR based on FLAIR, PFS (R2 = 0.46), and OS (R2 = 0.68). CONCLUSION: EOTR based on FLAIR and 5-ALA fluorescence is feasible. Safety of resection relies on the use of neuromonitoring and intraoperative multimodal imaging tools. FLAIR-based EOTR appears to be a stronger survival predictor compared to gadolinium-enhancing, T1-based resection.

Microsurgical Clipping Compared with New and Most Advanced Endovascular Techniques in the Treatment of Unruptured Middle Cerebral Artery Aneurysms: A Meta-Analysis in the Modern Era.

OBJECTIVE: Analyzing occlusion, complications rate, and clinical results in unruptured saccular middle cerebral artery aneurysms (MCAAs) comparing clipping with the most advance and newer endovascular techniques. METHODS: We conducted a literature research from January 2009 to December 2018 to evaluate the efficacy and safety of microsurgical clipping or endovascular treatment with new devices (such as Flow-diverter or Woven EndoBridge) in patients with unruptured MCAAs. We extracted data involved: study and intervention features, occlusion rate; time of occlusion assessment; and clinical outcome. RESULTS: A total of 29 studies and 1552 patients with unruptured saccular MCAAs were included in our analysis (464 patients included in the endovascular group, 1088 patients in the surgical group). Overall, the rate of long-term complete/near-complete occlusion was 78.1% (311/405, 95% confidence interval [CI], 69%-87.1%) and 95.7% (113/118, 95% CI, 92%-99.3%) after endovascular and surgical treatments, respectively (P = 0.001). The long-term complete occlusion rate was 60% (153/405, 95% CI, 45%-74%) and 95% (112/118, 95% CI, 90%-98%) after endovascular and surgical treatments, respectively (P = 0.001). The overall rate of treatment-related complications was 5.6% (33/464, 95% CI, 3.6%-7.7%) and 2.9% (37/1088, 95% CI, 0.8%-5%) among the endovascular and surgical groups, respectively (P = 0.001). Endovascular treatments were associated with higher rates of good neurologic outcome (283/293 [97%], 95% CI, 95%-98% vs. 570/716 [84%], 95% CI, 67%-98%; P = 0.001). No difference was found for the mortality (3/464 [1.5%], 95% CI, 0.4%-2.6% vs. 1/1088, 95% CI, 0.1%-0.6%; P = 0.5). CONCLUSIONS: Treatment-related complication and mortality are comparable among these techniques and the risk of aneurysm rupture seems very low for both strategies. The endovascular approach seems to increase the probability of good functional outcome after treatment, compared with surgery.

Radiological evaluation of ex novo high grade glioma: velocity of diametric expansion and acceleration time study.

BACKGROUND: One of the greatest neuro-oncological concern remains the lack of knowledge about the etiopathogenesis and physiopathology of gliomas. Several studies reported a strict correlation between radiological features and biological behaviour of gliomas; in this way the velocity of diametric expansion (VDE) correlate with lower grade glioma aggressiveness. However, there are no the same strong evidences for high grade gliomas (HGG) because of the lack of several preoperative MRI. PATIENTS AND METHODS: We describe a series of 4 patients affected by HGG followed from 2014 to January 2019. Two patients are male and two female; two had a pathological diagnosis of glioblastoma (GBM), one of anaplastic astrocytoma (AA) and one had a neuroradiological diagnosis of GBM. The VDE and the acceleration time (AT) was calculated for fluid attenuated inversion recovery (FLAIR) volume and for the enhancing nodule (EN). Every patients underwent sequential MRI study along a mean period of 413 days. RESULTS: Mean VDE evaluated on FLAIR volume was 39.91 mm/year. Mean percentage ratio between peak values and mean value of acceleration was 282.7%. Median appearance time of EN after first MRI scan was 432 days. Mean VDE was 45.02 mm/year. Mean percentage ratio between peak values and mean value of acceleration was 257.52%. CONCLUSIONS: To our knowledge, this is the first report on VDE and acceleration growth in HGG confirming their strong aggressiveness. In a case in which we need to repeat an MRI, time between consecutive scans should be reduced to a maximum of 15-20 days and surgery should be executed as soon as possible.

The unfeasible made feasible: lumbar minimally invasive hybrid stabilization with dynamic rod and mini-open transforaminal lumbar interbody fusion.

Posterior dynamic stabilization of the lumbar spine is spreading as a viable alternative to spinal fusion, aiming to achieve an equally satisfactory clinical outcome without making the spine completely rigid. We describe the feasibility of a minimally invasive surgical technique used to implant a hybrid system and perform a mini-open (m-open) transforaminal lumbar interbody fusion (TLIF) in patients suffering from degenerative spondylolistesis and adjacent level's degenerative disc disease (DDD). Three patients (2 females), suffering from degenerative spondylolistesis and adjacent level's DDD, underwent two-level hybrid stabilization combining a rigid, circumferential fusion (with m-open TLIF) at the level involved by spondylolistesis and a dynamic stabilization at the adjacent one. Screws, hybrid rods as well as interbody cages were introduced using a simple minimally invasive technique. Clinical and radiological evaluation was performed pre- and postoperatively, and at 3, 6 and 12 months, respectively, using the Visual Analogue Scale and the Oswestry Disability Index questionnaire. Mean VAS and ODI score reduced from 8.3, preoperatively, to 5 and from 72.66 to 43.98, respectively. No surgery-related complications were observed and the mean postoperative hospitalization was 2.5 days. Postoperative and follow-up flexion-extension X-rays showed persisting motion at dynamically stabilized levels. Follow-up CT imaging confirmed interbody fusion at TLIF levels in all patients. Dynamic and hybrid stabilizations of the lumbar spine are typically performed using open surgery. This study reports the feasibility of a hybrid stabilization with m-open TLIF performed using a minimally invasive technique.

Pros and cons of a minimally invasive percutaneous subdural drainage system for evacuation of chronic subdural hematoma under local anesthesia.

OBJECTIVE: Chronic subdural hematoma (CSH) is a common neurosurgical disease among elderly population with concomitant degenerative neurological disorders. This is a retrospective series-control analysis of prospectively collected data, aiming to show advantages and indications of a minimally invasive, percutaneous drainage system for CSH. PATIENTS AND METHODS: We retrospectively analyse the clinical and radiological data of a minimally invasive, percutaneous draining system (Integra ™) used in fifteen patients (Group A; mean age: 75.7) with CSH, and compare them with those obtained from two retrospective series of patients: the first one (Group B 15 patients, mean age 77.1) treated with standard, single-burr hole technique for subdural drainage under general anaesthesia; the second one (Group C 15 patients, mean age 76.4) treated with standard, single-burr hole technique for subdural drainage under local anaesthesia and mild sedation. All The percutaneous procedures (Group A) were performed under local anaesthesia. RESULTS: Mean follow-up was 10.9 (range 3-14), 18.2 (range 10-29) and 15.2 (range 8-28) months in Group A, B and C respectively. Three of 15 and in Group B experienced a worsening of pre-existing neurodegenerative disorders after general anaesthesia. One patient in group C suffering from Parkinson's disease experienced a worsening of gait disturbances. Post-operative CT scans were performed at 48 h and 21 days after the operation. An early post-operative CT-scan, obtained immediately after surgical procedure, was performed in all Group A patients. No differences in CSH evacuation were observed comparing the three groups. Two recurrent hematomas, one in group A and one in group B, required revision. Post-operative hospitalization was similar (5.1 vs 5.7 vs 5.6 days, respectively, in group A, B and C) but analgesics use was lower in Group A. CONCLUSION: Pre-operative evaluation of radiological features of CSDHs is crucial in determining the right indication for a minimally invasive drainage. Minimally invasive treatments of CSH may reduce the use of anaesthetic drugs and worsening of pre-existing neurodegenerative disorders.

Tentorial Angioleiomyoma: A Rare Neurosurgical Entity. Case Report and Review of the Literature.

BACKGROUND: Angioleiomyoma (ALM) is a soft tissue neoplasm rarely described in the intracranial site. Because of their uncommon presentation, atypical neuroradiologic and pathologic features, ALMs are often misdiagnosed. CASE DESCRIPTION: We describe the neuroradiologic, clinical, and pathologic data of a 37-year-old male patient suffering from a tentorial ALM. He was admitted at our hospital because of a posterior cranial fossa mass. Magnetic resonance imaging (MRI) showed a left tentorial tumor, hypointense on T1-weighted sequences, with heterogeneous contrast enhancement after gadolinium injection ("salt-and-pepper" fashion) and slightly hyperintense signal on T2-weighted sequence. After surgery, pathological examination showed a tumor composed of several thick-walled blood vessels mixed with a population of deeply eosinophilic spindle-shaped smooth muscle cells arranged in bundles. Necrosis was absent. Neither cellular pleomorphism nor mitoses were detected. Immuno-histochemical analysis confirmed the smooth muscle phenotype of the spindle cell component: diffuse and strong positivity for alpha-smooth muscle actin, desmin, and h-caldesmon. Based on both morphologic and immunohistochemical findings, a diagnosis of primary intracranial ALM was rendered. CONCLUSIONS: We add to the literature the tenth case of this exceedingly rare tumor and submit that ALM should be suspected when a tentorial mass with a "flame-like" time-dependent pattern of contrast enhancement on MRI, a "salt-and-pepper" post-contrast appearance on MRI T1-weighted sequences, and a relation with large intracranial feeding vessels are present.

Three-Dimensional, High-Definition Exoscopic Anterior Cervical Discectomy and Fusion: A Valid Alternative to Microscope-Assisted Surgery.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) remains one of the most commonly taught procedures during residency and one of the most frequently performed by neurosurgeons. Neurosurgeons use microscopes to perform surgery and to train other surgeons. Although the microscope provides excellent illumination and magnification, its use will be limited to 2 people: the surgeon and the assistant. Consequently, the scrub nurse and residents watching 2-dimensional images on monitors will have a reduced perception of the surgical field depth and anatomical details. The exoscope has been introduced as an alternative to microscopes and endoscopes. We used a 3-dimensional (3D), high-definition exoscope (3D Vitom [Karl Storz, Tuttlingen, Germany]) in 2 patients undergoing 2-level ACDF for cervical myeloradiculopathy. METHODS: The exoscope was used during soft tissue dissection, discectomy, osteophytectomy, and cage insertion. Microsurgical drilling of the posterior osteophytes, which will usually require adequate magnification and proper microscope angulation, was also performed using the exoscope. RESULTS: The exoscope provided a 3D view of the surgical field similar to that provided by a microscope and allowed us to effectively and safely perform the required surgical steps. The main advantage of 3D exoscope-assisted surgery, compared with microscope-assisted surgery, is the possibility to generate videos with a similar view and image quality as perceived by the surgeon. Therefore, the didactic capabilities of exoscopic videos are greater than those provided by microscopic videos. Exoscopes are also smaller compared with microscopes, allowing for comfortable use from the early surgical steps to device implantation. CONCLUSION: We believe that exoscope-assisted surgery could become a safe and effective alternative to microscope-assisted surgery in ACDF.

CircSMARCA5 Regulates VEGFA mRNA Splicing and Angiogenesis in Glioblastoma Multiforme Through the Binding of SRSF1.

Circular RNAs are a large group of RNAs whose cellular functions are still being investigated. We recently proposed that circSMARCA5 acts as sponge for the splicing factor Serine and Arginine Rich Splicing Factor 1 (SRSF1) in glioblastoma multiforme (GBM). After demonstrating by RNA immunoprecipitation a physical interaction between SRFS1 and circSMARCA5, we assayed by real-time PCR in a cohort of 31 GBM biopsies and 20 unaffected brain parenchyma controls (UC) the expression of total, pro-angiogenic (Iso8a) and anti-angiogenic (Iso8b) mRNA isoforms of Vascular Endothelial Growth Factor A (VEGFA), a known splicing target of SRSF1. The Iso8a to Iso8b ratio: (i) increased in GBM biopsies with respect to UC (p-value < 0.00001); (ii) negatively correlated with the expression of circSMARCA5 (r-value = -0.46, p-value = 0.006); (iii) decreased in U87-MG overexpressing circSMARCA5 with respect to negative control (p-value = 0.0055). Blood vascular microvessel density, estimated within the same biopsies, negatively correlated with the expression of circSMARCA5 (r-value = -0.59, p-value = 0.00001), while positively correlated with that of SRSF1 (r-value = 0.38, p-value = 0.00663) and the Iso8a to Iso8b ratio (r-value = 0.41, p-value = 0.0259). Kaplan-Meier survival analysis showed that GBM patients with low circSMARCA5 expression had lower overall and progression free survival rates than those with higher circSMARCA5 expression (p-values = 0.033, 0.012, respectively). Our data convincingly suggest that circSMARCA5 is an upstream regulator of pro- to anti-angiogenic VEGFA isoforms ratio within GBM cells and a highly promising GBM prognostic and prospective anti-angiogenic molecule.

Retro-odontoid Degenerative Pseudotumour Causing Spinal Cord Compression and Myelopathy: Current Evidence on the Role of Posterior C1-C2 Fixation in Treatment.

BACKGROUND: A retro-odontoid pseudotumour compressing the spinal cord and causing myelopathy is often associated with an inflammatory condition such as rheumatoid arthritis. A degenerative non-inflammatory retro-odontoid pseudotumour responsible for clinically relevant spinal cord compression is a rare condition described in small clinical series and is likely associated with craniovertebral junction hypermobility or instability-like conditions. For several years, direct removal of the lesion through an anterior or lateral approach has been advocated as the best surgical option. However, in the last decade the posterior approach to the craniovertebral junction, to perform C1-C2 fixation and C1 laminectomy without removal of the retro-odontoid tissue, has demonstrated its efficacy in reducing retro-odontoid pannus as well as in obtaining improvement of myelopathy. METHODS: In this paper we analyse the clinical and radiological outcomes of seven patients (five males and two females) treated with posterior C1-C2 fixation and C1 laminectomy for a degenerative non-inflammatory retro-odontoid pseudotumour responsible for spinal cord compression. C1 laminectomy provided immediate spinal cord decompression. We also review the relevant literature focusing on associated cervical degenerative conditions that may contribute to triggering or acceleration of atlantoaxial hypermobility or 'instability', causing formation of the retro-odontoid tissue. RESULTS: The mean follow-up period (of six followed-up patients) was 55.8 months (range 10-96 months). In all cases the Nurick score at the latest follow-up visit demonstrated clinical improvement; magnetic resonance imaging during follow-up demonstrated progressive reduction of the retro-odontoid pseudotumour in all but one patient, who died of surgery-unrelated disease in the early postoperative period. No vascular or neural damage secondary to C1-C2 fixation was observed. CONCLUSION: C1-C2 fixation associated with C1 laminectomy is an effective surgical option to treat myelopathy secondary to a degenerative retro-odontoid pseudotumour. In these cases, direct removal of intracanalar tissue compressing the spinal cord is not required, as C1-C2 fixation is sufficient to cause its disappearance.

Spinal Arachnoiditis Ossificans: Report of Quadruple-Triggered Case.

BACKGROUND: Arachnoiditis ossificans (AO) is a rare condition often associated with previous spine surgery. Here we describe a unique case of a patient affected by ankylosing spondylitis (AS), presenting with progressive neurologic deterioration due to AO. We also review the literature on evaluation and management of patients suffering from AO. CASE DESCRIPTION: The 65-year-old patient had a history of previous spinal trauma and related thoracolumbar surgery. Magnetic resonance imaging revealed multiloculated intradural/extramedullary cysts on the posterior surface of the spinal cord at Th9-L1, with clustered nerve roots. Computed tomography, with 3-dimensional reconstruction, demonstrated a likely ossification of both the dura and arachnoid from Th9 to S1. Microsurgical debridement of scar tissue from previous surgery, drilling of posterior ossified plaques at Th11-Th12-L1, and marsupialization and drainage of arachnoid cysts at Th11-Th12 were performed. CONCLUSIONS: We submit that AS, spinal trauma, epidural hematoma, and related surgery may be synergistic and independent factors in the etiopathogenesis of AO. This should be considered in patients with AS and/or a history of spinal surgery who present neurologic worsening.

Out-of-third ventricle colloid cysts: review of the literature on pathophysiology, diagnosis and treatment of an uncommon condition, with a focus on headache.

INTRODUCTION: Colloid cysts are rare benign intracranial lesions classically described as "third ventricle colloid cysts" because of their location within the third ventricle. These lesions' clinical and diagnostic features are mainly related to intermittent or persistent obstruction of foramina of Monro causing cerebrospinal fluid (CSF) circulation impairment and symptoms of raised intracranial pressure. Few reports on colloid cysts located outside the third ventricle have been published over the years. This paper aims to review the existing literature on out-of-third ventricle colloid cysts, and introduces a new illustrative case of lateral ventricle colloid cyst surgically managed with endoscopic technique. EVIDENCE ACQUISITION: A literature review was performed through a Medline web-search, using "colloid cysts," "lateral ventricle colloid cysts," "fourth ventricle colloid cysts," "brain colloid cyst," "spinal colloid cysts" as keywords. All retrieved abstracts were screened and full-length text of papers suitable for inclusion were examined. An illustrative case has been added to the existing literature. A 45-year-old man complaining of recurrent headache underwent conservative treatment for 4 years. The unusual headache features as well as the uncommon onset and association with episodic mental impairment led to an initial diagnosis of anxiety disorder triggering the headache. A further worsening of headache and the lack of significant clinical benefit prompted further investigation. Computed-tomography (CT) of the brain showed asymmetrical dilatation of the right lateral ventricle, due to the presence of a cystic mass obstructing the foramen of Monroe. Patient underwent endoscopic resection of the cyst. EVIDENCE SYNTHESIS: The literature review revealed 16 papers reported between 1952 and 2016. In all cases included histological diagnosis of colloid cyst had been obtained. Clinical and radiological features, as well as surgical management in each case have been analyzed. In the case here reported, histological examination documented a colloid cyst. The postoperative course was uneventful, with progressive resolution of headache. CONCLUSIONS: Despite third ventricle colloid cysts are related to typical clinical and diagnostic features, non-third ventricle colloid cysts may be responsible for unusual clinical presentation, so making a correct diagnostic approach challenging. We submit that in cases of recurrent headache with unusual features and lacking signs of neurological deficits, a rare neurosurgical condition as an "ectopic" colloid cyst should be included in the differential diagnosis.

Thalamomesencephalic cavernoma: anterior transcallosal transchoroidal approach.

We present a case of a 62-year-old man with acute onset of diplopia, headache, and vomiting for a bleeding thalamomesencephalic cavernoma. The lesion was removed via the anterior transcallosal transchoroidal approach. His head was slightly flexed and a right paramedian craniotomy for an interhemispheric approach was performed. The interhemispheric fissure was split and, after callosotomy, the choroidal fissure was opened along the tenia fornicis to enter the velum interpositum and enlarge the foramen of Monro. The cavernoma was then identified and resected. There were no long-term postoperative neurological deficits. This approach is a valid alternative for thalamomesencephalic lesions. The video can be found here: https://youtu.be/DJdorbzDnH0.

Intraoperative Computed Tomography and Awake Craniotomy: A Useful and Safe Combination in Brain Surgery.

BACKGROUND: Awake surgery is an effective technique to improve safety in surgical resection of lesions involving eloquent areas of the brain. Intraoperative imaging guidance and neuronavigation are widely applied in neurosurgical procedures. However, data on the application of intraoperative imaging to awake craniotomies are limited. We report our experience with intraoperative computed tomography (i-CT) during awake surgery, focusing on technical feasibility and effectiveness. METHODS AND RESULTS: Four patients with a lesion located in an eloquent area of the brain-1 with a cavernous hemangioma, 1 with a high-grade glioma, and 2 with a low-grade glioma (LGG)-underwent awake surgery with neuronavigation guidance. In all patients, i-CT was used to evaluate the completeness of resection or the extent of residual tumor. Intraoperative ultrasound was also used during microsurgery to verify the presence of residual tumor. The use of i-CT us allowed to obtain updated images for neuronavigation and to correct for brain shift. CONCLUSIONS: i-CT in awake surgery is reliable and effective. It does not significantly affect the duration of surgery and does not add stress for the patient. The possibility to correct for brain shift also in awake patients can increase the precision and accuracy of surgery, particularly in cases of LGG, avoiding the resection of normal white matter or tumor remnants in noneloquent areas.