Impact of augmented reality fiber tractography on the extent of resection and functional outcome of primary motor area tumors

OBJECTIVE

This study aimed to evaluate the impact of augmented reality intraoperative fiber tractography (AR-iFT) on extent of resection (EOR), motor functional outcome, and survival of patients with primary motor area (M1) intra-axial malignant tumors.

METHODS

Data obtained from patients who underwent AR-iFT for M1 primary tumors were retrospectively analyzed and compared with those from a control group who underwent unaugmented reality intraoperative fiber tractography (unAR-iFT). A full asleep procedure with electrical stimulation mapping and fluorescein guidance was performed in both groups. The Neurological Assessment in Neuro-Oncology (NANO), Medical Research Council (MRC), and House-Brackmann grading systems were used for neurological, motor, and facial nerve assessment, respectively. Three-month postoperative NANO and MRC scores were used as outcome measures of the safety of the technique, whereas EOR and survival curves were related to its cytoreductive efficacy. In this study, p < 0.05 indicated statistical significance.

RESULTS

This study included 34 and 31 patients in the AR-iFT and unAR-iFT groups, respectively. The intraoperative seizure rate, 3-month postoperative NANO score, and 1-week and 1-month MRC scores were significantly (p < 0.05) different and in favor of the AR-iFT group. However, no difference was observed in the rate of complications. Glioma had incidence rates of 58.9% and 51.7% in the study and control groups, respectively, with no statistical difference. Metastasis had a slightly higher incidence rate in the control group, without statistical significance, and the gross-total resection and near-total resection rates and progression-free survival (PFS) rate were higher in the study group. Overall survival was not affected by the technique.

CONCLUSIONS

AR-iFT proved to be feasible, effective, and safe during surgery for M1 tumors and positively affected the EOR, intraoperative seizure rate, motor outcome, and PFS. Integration with electrical stimulation mapping is critical to achieve constant anatomo-functional intraoperative feedback. The accuracy of AR-iFT is intrinsically limited by diffusion tensor-based techniques, parallax error, and fiber tract crowding. Further studies are warranted to definitively validate the benefits of augmented reality navigation in this surgical scenario.

Intraoperative Augmented Reality Fiber Tractography for Primary Motor Area Glioma Resection

The implementation of intraoperative augmented reality fiber tractography (iAR-FT) into the surgical workflow for high-grade supratentorial gliomas has been shown to be effective and safe in maximizing the extent of resection and progression-free survival through the surgeon's enhanced 3-dimensional awareness of the spatial localization of fiber tracts.1-3 Primary motor area tumors present special challenges due to the high eloquence of the precentral gyrus and risk of postoperative onset or worsening of motor deficits, as well as limited postoperative plasticity.4 Although essential, electrical stimulation mapping (ESM) techniques have a number of limitations with respect to primary motor pathways, including a higher risk of intraoperative stimulation-evoked seizures, a risk of false negatives in the presence of preoperative deficits, a nonnegligible risk of permanent deterioration even in the presence of negative stimulation maps, and, most importantly, limited spatial resolution.4-8 The rationale for integrating ESM and iAR-FT is to compensate for the limitations of the former in terms of morphologic and spatial representation of fiber tracts. The benefits of coupling iAR-FT with ESM techniques allow for continuous integrated anatomical-functional feedback during surgery. In Video 1 we describe the key technical aspects and benefits of iAR-FT-assisted surgery for maximal safe gross total resection of a primary motor area grade IV astrocytoma.

Comparative Analysis of Surgical Working Corridors for Meckel Cave Trigeminal Schwannomas: A Quantitative Anatomic Study

BACKGROUND AND OBJECTIVES

Volumetric analysis of the working corridors of the interdural approach to the Meckel cave may lead to a selection of routes which are anatomically more advantageous for trigeminal schwannoma resection. The herein-reported anatomic study quantitively compares the infratrochlear (IT) transcavernous, anteromedial (AM), and anterolateral (AL) corridors, highlighting their feasibility, indications, advantages, and limitations.

METHODS

Anatomic boundaries and depth of Meckel cave, porus trigeminus, IT transcavernous, AM, and AL corridors were identified in 20 formalin-fixed latex-injected cadaveric heads and were subsequently measured. The corridor areas and volumes were derived accordingly. Each opening angle was also calculated. Angles and volumes were compared using analysis of variance. Statistical significance was set at a P -value <.05.

RESULTS

The IT transcavernous corridor volume was greater than that of the AM and AL. The opening angle of the AM middle fossa triangle was wider than the other 2.

CONCLUSION

The IT corridor can be advantageous for Meckel cave schwannomas invading the cavernous sinus and those with a notable extension into the posterior fossa because the transcavernous approach maximizes the working space into the retrosellar area. The AM middle fossa corridor is strategic in schwannomas confined to the Meckel cave with a minor extension into the posterior fossa. It raises the chance of total resection with a single approach involving the porus trigeminus opening.

Optic Foraminotomy versus Anterior Clinoidectomy for Small Superior-Projecting Paraclinoid Aneurysms: Visual and Angiographic Outcome Evaluation

INTRODUCTION

Optic foraminotomy (OF) has been recently proposed as an alternative to anterior clinoidectomy (AC) for selected types of paraclinoid aneurysms. In this study, OF and AC were compared for small superior-projecting paraclinoid aneurysms assuming visual and angiographic results as outcome measures. Indications for OF are also discussed.

METHODS

Data of patients who underwent surgery for a paraclinoid aneurysm in the last 10 years were collected across 3 tertiary hospitals. Small to regular-size and superior projecting aneurysms were sorted. Multiple and complex aneurysms were excluded. Records of patients who went through OF were compared with those of patients who underwent AC. Neurologic outcome was reported as a modified Rankin Scale. Aneurysm complete occlusion rate and rate of approach-related worsened vision were selected as outcome measures of efficacy and safety, respectively, of the OF versus AC. Unpaired t test and χ² test were used for numerical and categorical variables, respectively. A P value less than 0.05 was considered statistically significant.

RESULTS

OF and AC groups involved 18 and 25 patients, respectively. Complication rate, overall neurologic outcome, rate of approach-related worsened vision, and complete occlusion rate did not differ between the groups. The average follow-up was 51 ± 34 and 60 ± 41 months in the OF and AC groups, respectively.

CONCLUSIONS

Compared to AC, OF did not show either a higher rate of approach-related worsened vision or a lower aneurysm complete occlusion rate. OF can be considered a valid alternative to the AC for small superior-projecting dorsal ICA wall paraclinoid aneurysms.

Cranio-Orbito-Zygomatic Approach: Core Techniques for Tailoring Target Exposure and Surgical Freedom

Background: The cranio-orbito-zygomatic (COZ) approach is a workhorse of skull base surgery, and each of its steps has a precise effect on target exposure and surgical freedom. The present study overviews the key techniques for execution and tailoring of the COZ approach, focusing on the quantitative effects resulting from removal of the orbitozygomatic (OZ) bar, orbital rim, and zygomatic arch. Methods: A PRISMA-based literature review was performed on the PubMed/Medline and Web of Science databases using the main keywords associated with the COZ approach. Articles in English without temporal restriction were included. Eligibility was limited to neurosurgical relevance. Results: A total of 78 articles were selected. The range of variants of the COZ approach involves a one-piece, two-piece, and three-piece technique, with a decreasing level of complexity and risk of complications. The two-piece technique includes an OZ and orbitopterional variant. Superolateral orbitotomy expands the subfrontal and transsylvian corridors, increasing surgical freedom to the basal forebrain, hypothalamic region, interpeduncular fossa, and basilar apex. Zygomatic osteotomy shortens the working distance of the pretemporal and subtemporal routes. Conclusion: Subtraction of the OZ bar causes a tremendous increase in angular exposure of the subfrontal, transsylvian, pretemporal, and subtemporal perspectives avoiding brain retraction, allowing for multiangled trajectories, and shortening the working distance. The COZ approach can be tailored based on the location of the lesion, thus optimizing the target exposure and surgical freedom and decreasing the risk of complications.

Microsurgical Neurovascular Anatomy of the Brain: The Posterior Circulation (Part II)

Introduction:

Vascular complications of posterior fossa surgery are often deadly although widely preventable through in-depth knowledge of the microsurgical neurovascular anatomy of the infratentorial region and careful surgical planning. The target of this study is to provide a synoptic overview of the normal anatomy and anatomic variants of the infratentorial neurovascular system, critical to safely operate tumors and neurovascular pathologies of the posterior fossa.

Methods:

Two fresh-frozen and five formalin-fixed cadaveric heads were used. Cervical arteries and internal jugular veins were injected with red and blue latex, respectively. The heads were dissected under a surgical microscope, with magnifications ranging between 3x to 40x, focusing on the infratentorial region. The infratentorial arteries, their collaterals and perforating branches, the brainstem and cerebellar veins, the tentorial venous sinuses, and the relative vascular territories were summarized according to a synoptic approach.

Results:

The vertebral artery, basilar artery (BA), and posterior cerebral artery (PCA) are the main sources of the arterial supply of the brainstem and cerebellum through the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), the superior cerebellar artery (SCA), and the perforating arteries. The perforating arteries of the vertebrobasilar system derive from the PICA, BA, AICA, SCA, and PCA, and provide for a key contribution to the vascularization of the midbrain, pons, medulla oblongata, fourth ventricle, cerebellar and cerebral peduncles, thalamus, hypothalamus, subthalamus, posterior part of the internal capsule, and optic tract. The distal segments and branches of the PCA also add a significant arterial supply to the temporal, occipital, and parietal lobes. The venous outflow of the posterior fossa is a prerogative of the internal jugular veins via the tentorial venous sinuses.

Conclusion:

A perfect mastery of the arterial, venous, and cisternal anatomy of the infratentorial region is vital for the planning and execution of the whole range of posterior fossa approaches.

The Modular Concept in Skull Base Surgery: Anatomical Basis of the Median, Paramedian and Lateral Corridors

Introduction:

A thorough understanding of skull base anatomy is imperative to perform safely and effectively any skull base approach. In this article, we examine the microsurgical anatomy of the skull base by proposing a modular topographic organization in the median, paramedian, and lateral surgical corridors in relation to transcranial and endoscopic approaches.

Methods:

Five dry skulls were studied focusing on the intracranial and exocranial skull base. Two lines were drawn parallel to the lateral border of the cribriform plate of the ethmoid bone and foramen lacerum, respectively. Lines 1 and 2 delimited the median, paramedian and lateral corridors of the skull base. The bony structures that formed each corridor were carefully reviewed in relation to the planning and execution of the skull base transcranial and endoscopic approaches.

Results:

The midline corridor involves the crista galli, cribriform plate, planum and jugum sphenoidale, chiasmatic sulcus, tuberculum sellae, sellar region, dorsum sellae, clivus, and foramen magnum. The paramedian corridor includes the fovea ethmoidalis, the root of the lesser and greater sphenoid wing, anterior clinoid process, foramen lacerum, the upper half of the petro-occipital suture, and jugular tubercle. The lateral corridors include the orbital plates, sphenoid wings, squamosal and petrous parts of the temporal bone, caudal aspect of the petro-occipital suture, internal auditory canal, jugular foramen, the sulcus of the sigmoid sinus.

Conclusion:

In-depth three-dimensional knowledge of skull base anatomy based on the modular concept of the surgical corridors is critical for the planning and execution of the transcranial and endoscopic approaches.

Microsurgical Neurovascular Anatomy of the Brain: The Anterior Circulation (Part I)

Introduction:

Treatment of cranial neurovascular pathology requires a detailed understanding of the brain, head, and neck vasculature. This study aims at a comprehensive overview of the microsurgical anatomy of the anterior cerebral circulation.

Methods:

Five formalin-fixed adult cadaveric heads were used. Common carotid arteries, vertebral arteries, and internal jugular veins were injected with colored latex (red for arteries and blue for veins). The heads were dissected under a surgical microscope with magnifications ranging between 3× to 40× focusing on the anterior circulation. A synoptic approach was used to describe in detail the segments, branches, perforating arteries, veins, and vascular territories of the cerebral arteries and veins.

Results:

The anterior arterial circulation of the brain is provided by the internal carotid artery (ICA), anterior cerebral artery (ACA), middle cerebral artery (MCA), anterior communicating artery (ACoA), and perforating arteries. Perforating arteries of the anterior circulation arise from the ICA, ACA, MCA, ACoA, and posterior communicating artery (PCoA). The distal segments and collateral branches of the ICA, ACA, and MCA give the arterial supply to the largest part of the forebrain, whereas perforating arteries of the anterior circulation are related to the striatum, thalamus, and basal ganglia. The ACoA is the core functional anastomosis between the left and right ICA systems. The external carotid artery provides the vascular supply to the region of the face, head, and neck, and most of the meninges. The internal jugular venous system is composed of the internal and external jugular veins, which constitutes the outflow of the cerebral and facial venous system, respectively.

Conclusion:

Thorough knowledge of the topographic, cisternal, and functional anatomy of the anterior circulation of the brain is critical for surgery of the supratentorial lesions. (www.actabiomedica.it)

Supratentorial high-grade gliomas: maximal safe anatomical resection guided by augmented reality high-definition fiber tractography and fluorescein

OBJECTIVE

The theoretical advantages of augmented reality (AR) with diffusion tensor imaging (DTI)-based high-definition fiber tractography (HDFT) and sodium fluorescein (F) in high-grade glioma (HGG) surgery have not been investigated in detail. In this study, the authors aimed to evaluate the safety and efficacy profiles of HDFT-F microscope-based AR cytoreductive surgery for newly diagnosed supratentorial HGGs.

METHODS

Data of patients with newly diagnosed supratentorial HGGs who underwent surgery using the AR HDFT-F technique were reviewed and compared with those of a cohort of patients who underwent conventional white-light surgery assisted by infrared neuronavigation. The safety and efficacy of the techniques were reported based on the postoperative Neurological Assessment in Neuro-Oncology (NANO) scores, extent of resection (EOR), and Kaplan-Meier curves, respectively. The chi-square test was conducted for categorical variables. A p value < 0.05 was considered statistically significant.

RESULTS

A total of 54 patients underwent surgery using the AR HDFT-F technique, and 63 underwent conventional white-light surgery assisted by infrared neuronavigation. The mean postoperative NANO scores were 3.8 ± 2 and 5.2 ± 4 in the AR HDFT-F group and control group, respectively (p < 0.05). The EOR was higher in the AR HDFT-F group (p < 0.05) than in the control group. With a mean follow-up of 12.2 months, the rate of progression-free survival (PFS) was longer in the study group (log-rank test, p = 0.006) than in the control group. Moreover, the complication rates were 9.2% and 9.5% in the study and control groups, respectively.

CONCLUSIONS

Overall, AR HDFT-F-assisted surgery is safe and effective in maximizing the EOR and PFS rate for patients with newly diagnosed supratentorial HGGs, and in optimizing patient functional outcomes.

Shedding the Light on the Natural History of Intracranial Aneurysms: An Updated Overview

The exact molecular pathways underlying the multifactorial natural history of intracranial aneurysms (IAs) are still largely unknown, to the point that their understanding represents an imperative challenge in neurovascular research. Wall shear stress (WSS) promotes the genesis of IAs through an endothelial dysfunction causing an inflammatory cascade, vessel remodeling, phenotypic switching of the smooth muscle cells, and myointimal hyperplasia. Aneurysm growth is supported by endothelial oxidative stress and inflammatory mediators, whereas low and high WSS determine the rupture in sidewall and endwall IAs, respectively. Angioarchitecture, age older than 60 years, female gender, hypertension, cigarette smoking, alcohol abuse, and hypercholesterolemia also contribute to growth and rupture. The improvements of aneurysm wall imaging techniques and the implementation of target therapies targeted against inflammatory cascade may contribute to significantly modify the natural history of IAs. This narrative review strives to summarize the recent advances in the comprehension of the mechanisms underlying the genesis, growth, and rupture of IAs.

Pulsatile cerebrospinal fluid dynamics in Chiari I malformation syringomyelia: Predictive value in posterior fossa decompression and insights into the syringogenesis

Background:

Pathophysiological mechanisms underlying the syringomyelia associated with Chiari I malformation (CM-1) are still not completely understood, and reliable predictors of the outcome of posterior fossa decompression (PFD) are lacking accordingly. The reported prospective case-series study aimed to prove the existence of a pulsatile, biphasic systolic–diastolic cerebrospinal fluid (CSF) dynamics inside the syrinx associated with CM-1 and to assess its predictive value of patients' outcome after PFD. Insights into the syringogenesis are also reported.

Methods:

Fourteen patients with symptomatic CM-1 syringomyelia underwent to a preoperative neuroimaging study protocol involving conventional T1/T2 and cardiac-gated cine phase-contrast magnetic resonance imaging sequences. Peak systolic and diastolic velocities were acquired at four regions of interest (ROIs): syrinx, ventral, and dorsal cervical subarachnoid space and foramen magnum region. Data were reported as mean ± standard deviation. After PFD, the patients underwent a scheduled follow-up lasting 3 years. One-way analysis of variance with Bonferroni Post hoc test of multiple comparisons was performed P was <0.001.

Results:

All symptoms but atrophy and spasticity improved. PFD caused a significant velocity changing of each ROI. Syrinx and premedullary cistern velocities were found to be decreased within the 1^st month after PFD (<0.001). A caudad and cephalad CSF jet flow was found inside the syrinx during systole and diastole, respectively.

Conclusion:

Syrinx and premedullary cistern velocities are related to an early improvement of symptoms in patients with CM-1 syringomyelia who underwent PFD. The existence of a biphasic pulsatile systolic–diastolic CSF pattern inside the syrinx validates the “transmedullary” theory about the syringogenesis.

Gene Polymorphisms Increasing the Risk of Intracranial Aneurysms: Interleukin-6 -174G>C and -572G>C (Part II)

Introduction The interleukin-6 (IL-6), a proinflammatory cytokine, supports the adaptive immune response and regulates inflammatory processes. The -174 G>C and -572 G>C promoter polymorphisms of the IL-6 gene take part in the pathogenesis of intracranial aneurysms (IAs) and influence the clinical presentation of subarachnoid hemorrhage. This meta-analysis purposes to evaluate whether and which IL-6 allelic variations are related to a risk of IAs formation. Methods A PRISMA-based literature search was performed on the PubMed/Medline and Web of Science databases. The keywords used were "interleukin-6," "IL-6," "polymorphism," "interleukin-6 genotype," combined with "intracranial aneurysms" and "subarachnoid hemorrhage." Only human case-control studies, with a study (IAs) and a control group, written in English, and published in the last 15 years were selected. A meta-analysis was performed, estimating odds ratios and 95% confidence intervals in fixed- or random-effects models, as applicable. Statistical analysis was conducted with RevMan 5.0 software. Results 9 studies were eligible. No associations were found between -174 G>C polymorphisms and IAs susceptibility. Notable results were reported by the analysis of -572G>C polymorphisms. -572GG/GC/CC genotypes were strongly related to IAs occurrence with a statistical significance of p=0.03, p=0.0009, and p=0.00001, respectively. Conclusion A higher incidence of -572G>C promoter polymorphisms were demonstrated in the IAs group, highlighting the pivotal role of inflammatory genes in the natural history of brain aneurysms. Additional studies are required considering the racial heterogenicity and the need to widen the population sample.

Pterional Approach

The pterional approach is a workhorse in neurosurgery, to the point where perfect knowledge of its execution is essential in neurosurgical daily practice. The pterional transsylvian corridor is used to treat aneurysms involving anterior circulation, basilar apex, the proximal segment of the superior cerebellar and posterior cerebral artery, arteriovenous malformations and cavernous hemangiomas of the basal forebrain, anterior and middle skull base tumors, gliomas of the frontal, parietal, and temporal opercula, insula, mediobasal temporal region, cerebral peduncles, interpeduncular fossa, and also orbital lesions. We herein overview the core technique and variations of the pterional approach aimed at broadening surgical freedom and decreasing the risk of approach-related complications.

Posterior Circulation Aneurysms: A Critical Appraisal of a Surgical Series in Endovascular Era

The advent of the endovascular era has apparently decreased the role of microneurosurgery for many of the posterior circulation aneurysms. This study consists of a critical appraisal of a retrospective surgical series regarding posterior circulation aneurysms, targeted to define whether microneurosurgery still has a role for some of these. In 28 years, 157 aneurysms were surgically treated, 98 of which ruptured. The Average patient age was 56.7 ± 14.2 years, while in hemorrhagic cases, the mean Hunt-Hess score was 2.17 ± 0.8. Basilar tip, vertebral artery and proximal posterior inferior cerebellar artery were the most frequently involved sites. The treatment consisted of 128 clippings, 19 trappings, 7 wrappings, and 3 bypasses. A total exclusion was achieved in 88.5% of the aneurysms. An average follow-up of 67.1 ± 61.3 months proved no recurrences. The best results were observed in patients <65 years old who harbored small-to-regular aneurysms of the basilar tip, distal cerebellar arteries, or vertebral artery.Clipping proved to be a definitive and durable treatment for a large part of posterior circulation aneurysms, whereas bypass allows for treating aneurysms not amenable for coiling, stenting, or clipping. The present study confirms that microneurosurgery continues to have a paramount role within neurovascular pathology.

Far Lateral Approach

The far lateral approach is an inferolateral extension of the lateral suboccipital approach. Designed for clipping of the aneurysms of the vertebrobasilar junction and proximal segments of the posterior inferior cerebellar artery, it became over the years a workhorse approach for ventral foramen magnum meningiomas and other intradural lesions located anterior to the dentate ligament.  This article summarizes the technical key aspects of the far lateral approach and transcondylar, supracondylar, and paracondylar extension.

Cranio-Orbito-Zygomatic Approach

The cranio-orbito-zygomatic (COZ) approach consists of an extension of the pterional approach characterized by the removal of the superolateral part of the orbital rim and zygoma. This key step tremendously increases the angular exposure to some deep targets and overall surgical freedom to the lesion. In this article we review the technical variations of the COZ approach, mainly focusing on the differential quantitative effects coming from the orbital osteotomy compared to the zygomatic one.

Gene Polymorphisms Increasing the Risk of Intracranial Aneurysms: Interleukin-1β -511C>T (Part I)

Introduction Intracranial aneurysms (IAs) are devastating cerebrovascular diseases with multifactorial etiology. The role of inflammation is indisputable, and interleukins are pivotal in supporting local inflammatory pathways and endothelial dysfunction at the aneurysm wall. In the light of insufficient evidence reported in the literature, this meta-analysis was aimed to investigate the genetic linkage between IL-1β (rs16944) -511C>T polymorphisms and IAs susceptibility. Methods A comprehensive online literature review was completed using the PubMed/Medline and Web of Science databases in accordance with the PRISMA guidelines. "Interleukin-1β," "IL-1β," "polymorphism," "intracranial aneurysm," and "subarachnoid hemorrhage" were the main keywords. Only human case-control studies, published from 2005 to 2021, written in English or translated, were screened. In the statistical analysis, we applied the fixed- and random-effect models, according to the level of heterogeneity, to assess the odds ratios (ORs) and 95% confidence intervals (CIs). RevMan 5.0 software was used for the statistics. Results Only 4 studies were eligible, with a total of 2070 patients, 1050 of which were assigned to the study group. Combined results showed a statistically significant association between the risk of IAs and -511CC (OR=0.79, 95% CI [0.65-0.95], p=0.01), and CT (OR=0.69, 95% CI [0.58-0.82], p<0.0001; OR=0.71, 95% CI [0.55-0.93], p=0.01) allele variations, both in the fixed- and random- models. No correlation was identified for the -511TT genotype (p=0.42; p=0.78). All the texts showed a low level of publication bias. Conclusion The present meta-analysis proved a potential role of IL-1β -511CC/CT genotypes in the pathogenesis of IAs. Additional studies are imperative to explain the underlying neuroimmune mechanisms, also allowing tailoring the potential inflammatory-target therapies for IAs.

Microneurosurgery for Paraclinoid Aneurysms in the Context of Flow Diverters

The advent of flow diverter (FD) stents has apparently reduced the role of microneurosurgery for paraclinoid aneurysms despite sparse high-quality evidence about their long-term effects.The present study critically reviews the overall results of a microneurosurgical series of 57 paraclinoid aneurysms.Of these aneurysms, 47.4% were regular in size while 19.3 were giant. Barami type I was predominant. In 21 aneurysms a hemorrhagic onset occurred. Pterional approach with intradural anterior clinoidectomy was preferred by far. Clipping was possible in 91.2% of aneurysms and a high-flow bypass was the choice in five cases. An mRS of 0-2 was achieved in 77.3% of patients, typically <50 years old.Visual field appeared improved or unchanged in 36.3% and 63.6% of the symptomatic patients, respectively. In 76.1% of incidental aneurysms, campimetry was unaffected by surgery.A complete aneurysm exclusion was achieved in 93% of cases using a single procedure. No recurrences were documented on an average follow-up of 54.1 ± 34 months.Microneurosurgery is still a valuable, definitive, and durable option for Barami type Ia, Ib, or II paraclinoid aneurysm, especially in patients <50 years old and visually symptomatic. Conditions other than these are ideal candidates for FD stents.

Brain location and tumor biological markers in high and low grade gliomas: our experience

BACKGROUND

Recent studies suggest gliomas location may be correlated with specific biological signatures. Our purpose was to focus on the possible correlation between MGMT metilation status and Ki67 positivity with patient age, glioma location and lateralization.

METHODS

We performed a retrospective evaluation to assess the correlation between MGMT metilation status and Ki67 index positivity with patient age, glioma location and lateralization.

RESULTS

The study included 174 supratentorial gliomas. Of these, 144 tumors were high grade gliomas (HGGs) and 30 tumors were low grade gliomas (LGGs). In HGG group we detected an association between tumor location and MGMT status. Those GBMs located in the frontal lobe were significantly associated with MGMT methylated status (MGMT+) and Ki67<30% than those GBMs located in other sites; while those GBMs located in the temporal lobe were associated with MGMT unmethylated (MGMT-) status. In anaplastic gliomas, we found an association between the involvement of the frontal lobe with MGMT+ status and Ki67<30%. In LGG group, our results showed that both frontal and temporal lobe were associated with a Ki67<30% and there was a predictive value for MGMT methylation status when patient age increased.

CONCLUSIONS

Our findings suggest there is a high variability in anatomical distribution of biological glioma markers and this high heterogeneity may have a clinical role. Moreover our study supports the idea that frontal lobe HGGs may be biologically favorable. Considering that as all glioma with lobar location are more amenable to radical surgical resection, it may be assumed that frontal tumor can have a better prognosis, and we have shown, to our knowledge for the first time, this is true both for HGG and for LGG.

Dye-Perfused Human Placenta for Vascular Microneurosurgery Training: Preparation Protocol and Validation Testing

BACKGROUND

Human placenta is recognized as a valuable vascular microneurosurgery training model because of its abundant availability, ethical acceptance, and analogous vasculature with other vessels of the human body; however, human placenta laboratory preparation techniques are not well described in the literature. This study outlines a detailed and standardized laboratory protocol for preparation of a color-perfused human placenta model. Survey-based validation of the model is also reported herein.

METHODS

The protocol involved cleaning and cannulation of the umbilical vein and arteries, irrigation with heparin, and storage at 3°C or freezing at -18°C. Before use, arteries were perfused with carmine/cochineal, and veins were perfused with methylthioninium chloride. A questionnaire with 5 questions was administered to 40 participants among attending or resident neurosurgeons, otolaryngologists, and maxillofacial surgeons on 4 consecutive microsurgical courses to assess the reliability of the placenta model. Trainees were divided into 3 groups based on their experience. A χ² test was used to identify differences between groups.

RESULTS

Forty-two placentas were considered appropriate for training and were successfully perfused with dyes. Thirty-three participants completed the questionnaire, of which most, especially advanced and intermediate participants, indicated the placenta as a valuable, accurate, and reproducible model. No differences were observed among the groups.

CONCLUSIONS

The human placenta is an excellent tool for vascular microneurosurgery laboratory training. Color perfusion enhances the reliability of this model, which was validated by most surgeons, regardless of their experience.

Anterolateral approach for subaxial vertebral artery decompression in the treatment of rotational occlusion syndrome: results of a personal series and technical note

OBJECTIVES

To report the results of a retrospective series and a technical note about the anterolateral approach for the treatment of the rotational occlusion syndrome (ROS) involving the subaxial V2 segment of the vertebral artery (VA).

METHODS

We retrospectively reviewed the data of a cohort of patients that underwent an anterolateral approach to decompress the VA as they suffered from ROS secondary to a subaxial compression. A dynamic study with ultrasonography, CT, MRI, and catheter-based angiography were obtained in all cases. Severe symptomatology and cerebellar-brainstem strokes were indications for surgery. The anterolateral approach involved a pre-sternocleidomastoid precarotid exposure. The retro-longus colli and pre-scalenic corridors were used to access the C5-C6 and C3-C4 segment, respectively, and to perform the decompression.

RESULTS

Twelve patients were treated. Recurrent drop attacks were present in all cases. Osteophytes at C5 and C6 were the most common causes of subaxial VA compression. Anterior decompression stand-alone was performed in all but 1 patient. A recurrent laryngeal nerve palsy and a numbness of the C5 nerve root were the only complications observed, both transient. A satisfactory untethering of the VA with a complete recovery was achieved in all patients, apart from those with severe infratentorial strokes.

DISCUSSION READ

Anterolateral approach allows for an effective and safe treatment of the ROS involving the subaxial portion of the VA. Retro-longus colli and pre-scalenic corridors, developed through a precarotid exposure, have an anatomical rationale in decreasing the risks of complications. Decompression stand-alone is adequate in almost the totality of cases.

Surgical Management of Giant Intracranial Aneurysms: Overall Results of a Large Series

OBJECTIVE

To review and discuss surgical treatment options for giant intracranial aneurysms (GIAs), focusing on indications, technical aspects, and results, along with some illustrative cases.

METHODS

We reviewed the data of 82 consecutive patients surgically managed between January 2000 and December 2019 for treatment of a GIA.

RESULTS

Male sex and hemorrhage at presentation were prevalent. The average follow-up was 81.2 ± 45 months. The anterior circulation was involved in 76.8% of GIAs. If the GIA showed a clear neck, minimal atherosclerosis, or intrasaccular thrombosis, and ≤2 branches arising from the neck, it was reconstructed. This procedure was possible in 78% of cases. The technique also involved temporary clipping, remodeling, and thrombectomy, as well as fragmentation techniques. Angioarchitectural features other than these techniques underwent bypass and aneurysm trapping. Most bypasses were extracranial to intracranial and high flow. Flow capacity, collateral circulation, and availability of the donor vessel mainly affected the choice of the type of bypass. Overall, successful exclusion of the GIA was 91.4%. The need for retreatment and complication rate were 3.6% and 19.5%, respectively. A good overall outcome (modified Rankin Scale score 0-3) was achieved in 84.2% of patients, and mortality was 10%.

CONCLUSIONS

Microneurosurgical techniques still maintain a significant role for most GIAs, with a high durability and acceptable rate of morbidity and mortality. Clip reconstruction is the first-line surgical treatment option, whereas bypass is indicated in cases of planned or unplanned sacrifice of the parent artery to prevent long-term ischemic complications.

Subaxial Vertebral Artery Rotational Occlusion Syndrome: An Overview of Clinical Aspects, Diagnostic Work-Up, and Surgical Management

Extrinsic compression of the subaxial vertebral artery (VA) may cause rotational occlusion syndrome (ROS) and contribute to vertebrobasilar insufficiency potentially leading to symptoms and in severe cases, to posterior circulation strokes. The present literature review aimed to report the main clinical findings, diagnostic work-up, and surgical management of the subaxial VA-ROS, the diagnosis of which can be difficult and is often underestimated. An illustrative case is also presented. A thorough literature search was conducted to retrieve manuscripts that have discussed the etiology, diagnosis, and treatment of ROS. Total 41 articles were selected based on the best match and relevance and mainly involved case reports and small cases series. The male/female ratio and average age were 2.6 and 55.6±11 years, respectively. Dizziness, visual disturbances, and syncope were the most frequent symptoms in order of frequency, while C5 and C6 were the most affected levels. Osteophytes were the cause in >46.2% of cases. Dynamic VA catheter-based angiography was the gold standard for diagnosis along with computed tomography angiography. Except in older patients and those with prohibitive comorbidities, anterior decompressive surgery was always performed, mostly with complete recovery, and zero morbidity and mortality. A careful neurological evaluation and dynamic angiographic studies are crucial for the diagnosis of subaxial VA-ROS. Anterior decompression of the VA is the cure of this syndrome in almost all cases.

Supraorbital keyhole approach: Pure endoscopic and endoscope-assisted perspective

OBJECTIVE

To assess the assumed advantages of pure endoscopic and endoscope-assisted methods for the supraorbital keyhole approach. The aim is to demonstrate visibility and accessibility of the pure endoscope approach as a possible standard approach for the supraorbital keyhole approach.

PATIENTS AND METHODS

We performed eight dissections on four cadaver heads using an operating microscope, an endoscope, and neuronavigation. The visibility and accessibility of the anterior and middle cranial fossae regions were compared for each. Special structures were defined to assess their preservation in both approaches. We used pure endoscopy on the eight sides and with a microscope on those same eight sides. Accessibility was quantified for key structures using linear measurements taken with the navigation system. In addition, we present clinical cases in which an endoscope-assisted supraorbital approach was employed.

RESULTS

Our measurements have been reported for each side in the formalin-fixed heads as the mean ± SD (in mm) from the bone margin to selected regions. Moreover, image analysis was performed using ImageJ software to compare selected surface area measurements between the endoscope and microscope images on each side for all cadaveric available specimens. There were no significant statistical differences between visualization of the selected areas. This means that by visual analysis both endoscopic and microscopic images can provide the surgeon nearly the same visibility and accessibility of a selected region.

CONCLUSION

A pure endoscopic method can be used to conduct the supraorbital keyhole approach when the endoscope is used as a primary tool. Our recommendation is to use the measurements described in this study for preoperative planning of the keyhole approach. We believe that with advances in neuro-endoscope technology, and instrumentations, the endoscopic approach may replace the microscopic approach in the near future.

The cell-based approach in neurosurgery: ongoing trends and future perspectives

OBJECTIVE

Examination of the current trends and future perspectives of the cell-based therapies in neurosurgery.

METHODS

A PubMed/MEDLINE-based systematic review has been performed combining the main Medical Subject Headings (MeSH) regarding the cell- and tissue-based therapies with the "Brain", "Spinal Cord", "Spine" and "Skull" MeSH terms. Only articles in English published in the last 10 years and pertinent to neurosurgery have been selected.

RESULTS

A total of 1,173 relevant articles have been chosen. Somatic cells and gene-modification technologies have undergone the greatest development. Immunotherapies and gene therapies have been tested for the cure of glioblastoma, stem cells mainly for brain and spinal cord traumatic injuries. Stem cells have also found a rationale in the treatment of the cranial and spinal bony defects, and of the intervertebral disc degeneration, as well.Most of the completed or ongoing trials concerning the cell-based therapies in neurosurgery are on phase 2. Future perspectives involve the need to overcome issues related to immunogenicity, oncogenicity and routes for administration. Refinement and improvement of vector design and delivery are required within the gene therapies.

CONCLUSION

The last decade has been characterised by a progressive evolution of neurosurgery from a purely mechanical phase to a new biological one. This trend has followed the rapid and parallel development of translational medicine and nanotechnologies.The introduction of new technologies, the optimisation of the already existing ones, and the reduction of costs are among the main challenges of the foreseeable future.

Anterolateral Approach for Retrostyloid Superior Parapharyngeal Space Schwannomas Involving the Jugular Foramen Area: A 20-Year Experience

BACKGROUND

Schwannomas encompassing the superior parapharyngeal space are challenging lesions because of the anatomical complexity of this region and the frequent involvement of the neurovascular structures of the jugular foramen. The purpose of this study is to report the technical aspects and the advantages of the anterolateral approach, here proposed for schwannomas of this complex area.

METHODS

The main steps of the anterolateral approach are described in detail, along with the results of a consecutive series of 38 patients with a retrostyloid superior parapharyngeal schwannoma involving the jugular foramen operated on by means of this route between 1999 and 2019.

RESULTS

The supine position is generally preferred. The medial border of the sternocleidomastoid muscle, mastoid tip, and superior nuchal line are the landmarks for the hockey-stick skin incision. The accessory nerve is retrieved and mobilized cranially. Detachment of the sternocleidomastoid, digastric, and nuchal muscles allows for a 180° exposure of the extracranial side of the jugular foramen. Three working corridors, namely the pre-carotid, pre-jugular, and retro-jugular, allow access to the deeper part of the jugular foramen area and the superior parapharyngeal space. In the present series, a gross total resection was achieved in 89.4% of the patients. Three recurrences occurred after an average follow-up of 80.5 ± 51 months.

CONCLUSIONS

The anterolateral approach is highly effective in the treatment of retrostyloid superior parapharyngeal space schwannomas involving the jugular foramen. Its simplicity of execution, versatility, and very low morbidity are among its main strengths.

Dysembryoplastic Neuroepithelial Tumors: What You Need to Know

OBJECTIVE

An updated and comprehensive review on dysembryoplastic neuroepithelial tumor (DNET) focusing on differential diagnosis, atypical presentation, seizure outcome, and risk of malignant transformation.

METHODS

A PubMed/MEDLINE-based literature search has been performed using "dysembryoplastic neuroepithelial tumor" as a keyword. Two treated cases characterized by an atypical presentation have been reviewed.

RESULTS

Of 1162 articles, 200 relevant studies have been selected. DNET is a benign mixed neuronal-glial tumor causing drug-resistant epilepsy primarily in children and young adults. The typical radiological pattern is a magnetic resonance imaging (MRI) T1-hypointense, T2-, and fluid-attenuated inversion-recovery hyperintense multicystic lesion involving the cerebral cortex with no edema. Contrast enhancement may be present and a focal cortical dysplasia is commonly associated with it. MRI diffusion, perfusion, and spectroscopy have a paramount role in the differential diagnosis. The "specific glioneuronal elements" are pathognomonic. They are positive for S100 protein, synaptofisin, neuronal nuclei, oligodendrocyte transcription factor, neurite outgrowth inhibitor, and microtubule-associated protein 2, but negative for glial fibrillary acidic protein. As opposed to v-myb avian myeloblastosis viral oncogene homolog, isocitrate dehydrogenase-1/isocitrate dehydrogenase-2 mutation and codeletion 1p-19q, fibroblast growth factor receptor 1 and BRAF V600E mutations are present. The effectiveness of surgery on seizure outcome has been established. Rare malignant transformations have been reported, especially in extra-temporal and complex forms.

CONCLUSIONS

Advanced MRI techniques are fundamental in the differential diagnosis for DNET versus other low-grade gliomas. Immuno-phenotype assessment and search for fibroblast growth factor receptor 1 and BRAF V600E mutations limit the risk of misdiagnoses. A gross total tumor removal is generally associated with a seizure-free outcome. Recurrences and malignant transformations may rarely follow, legitimizing MRI surveillance in cases of subtotal tumor resection.

Simple schwannomatosis or an incomplete Coffin-Siris? Report of a particular case

BACKGROUND

Schwannomatosis is a genetic disorder that belongs to NF family. The mutation of SMARCB1 gene has been related to this entity and Coffin-Siris syndrome, as well. We reported a case of a female patient with SMARCB1 mutation who has developed a spontaneuous spleen rupture.

CASE DESCRIPTION

A 28 years old female patient with a story of a Sjogren syndrome, celiac disease and a surgically treated schwannoma, presented to our observation in July 2013 for a pain on the left elbow, where a tumefation was present. After neuroradiological evaluations, a surgical resection was performed and a schwannoma was diagnosed. Genetic exams revealed a puntiform SMARCB1 gene mutation. During 2015, she was subdued to the removal of an another schwannoma located into the cervical medullary canal. Few months later, she was operated in an another hospital for a spontaneous spleen rupture in a possible context of wandering spleen.

CONCLUSION

We think that the patient could suffer from a partially expressed Coffin-Siris syndrome. No cases of spontaneous rupture in a context of wandering spleen have been ever described as for as schwannomatosis or Coffin-Siris syndrome are concerned. More cases are necessary to establish a direct relationship.

Targeted therapy of human glioblastoma via delivery of a toxin through a peptide directed to cell surface nucleolin

Targeted anticancer therapies demand discovery of new cellular targets to be exploited for the delivery of toxic molecules and drugs. In this perspective, in the last few years, nucleolin has been identified as an interesting surface marker to be used for the therapy of glioblastoma. In this study, we investigated whether a synthetic antagonist of cell-surface nucleolin known as N6L, previously reported to decrease both tumor growth and tumor angiogenesis in several cancer cell lines, including glioblastoma cells, as well as endothelial cells proliferation, could be exploited to deliver a protein toxin (saporin) to glioblastoma cells. The pseudopeptide N6L cross-linked to saporin-S6 induced internalization of the toxin inside glioblastoma cancer cells. Our results in vitro demonstrated the effectiveness of this conjugate in inducing cell death, with an ID50 four orders of magnitude lower than that observed for free N6L. Furthermore, the preliminary in vivo study demonstrated efficiency in reducing the tumor mass in an orthotopic mouse model of glioblastoma.

NOS2 expression in glioma cell lines and glioma primary cell cultures: correlation with neurosphere generation and SOX-2 expression

Nitric oxide has been implicated in biology and progression of glioblastoma (GBM) being able to influence the cellular signal depending on the concentration and duration of cell exposure. NOS2 (inducible nitric oxide synthase) have been proposed as a component of molecular profile of several tumors, including glioma, one of the most aggressive primary brain tumor featuring local cancer stem cells responsible for enhanced resistance to therapies and for tumor recurrence. Here, we investigated the NOS2 mRNA expression by reverse transcription-PCR in human glioma primary cultures at several grade of malignancy and glioma stem cell (GSC) derived neurospheres. Glioma cell lines were used as positive controls both in terms of stemness marker expression that of capacity of generating neurospheres. NOS2 expression was detected at basal levels in cell lines and primary cultures and appeared significantly up-regulated in cultures kept in the specific medium for neurospheres. The immunofluorescence analysis of all cell cultures to evaluate the levels of SOX-2, a stemness marker aberrantly up-regulated in GBM, was also performed. The potential correlation between NOS2 expression and ability to generate neurospheres and between NOS2 and SOX-2 levels was also verified. The results show that the higher NOS2 expression is detected in all primary cultures able to arise neurosphere. A high and significant correlation between NOS2 expression and SOX-2 positive cells (%) in all cell cultures maintained in standard conditions has been observed. The results shed light on the potential relevance of NOS2 as a prognostic factor for glioma malignancy and recurrence.

Giant and Very Large Intracranial Aneurysms: Surgical Strategies and Special Issues

Giant intracranial aneurysms (GIAs) and very large intracranial aneurysms (VLAs) have a poor natural history because of a high incidence of bleeding and strokes. These lesions always represent a great challenge for neurosurgeons and interventional neuroradiologists because of some peculiar intrinsic features such as size, angioarchitecture, wide neck, mass effect, intraluminal thrombosis, atherosclerotic changes, involvement of branches and perforators, and a frequent need to perform revascularization procedures. The results of a cumulative surgical series of 75 VLAs and GIAs are reported. Thirty-three aneurysms were unruptured. Sixty aneurysms underwent direct surgical treatment consisting of 56 direct clippings, 3 trappings w/o revascularization, and 1 wrapping. Fifteen aneurysms were treated by means of extracranial to intracranial (EC-IC) high-flow bypass. An mRS score ranging between 0 and 2 was observed in 54 patients, whereas an mRS of 3 was seen in 5 patients. Four patients had a severe disability (mRS 4-5) and six patients died. Aneurysm's fragmentation, with stacking and seating clips, thrombectomy, and aneurysmorrhaphy were the techniques most frequently employed. Revascularization options involving EC-IC high-flow bypass were used in cases not amenable for direct treatment. Some technical tips and special issues related to the surgical management of these complex lesions are discussed.

Surgical Treatment of Arteriovenous Malformations: Role of Preoperative Staged Embolization

Preoperative embolization is complementary to surgery for large brain arteriovenous malformations (AVMs). From January 2005 to December 2015, 69 patients harboring an AVM were managed in our department by the same surgeon (RG). Forty one were ruptured and 65 were supratentorial. Thirty nine smaller AVMs were treated with surgery stand-alone, whereas, for 30 larger malformations, surgery was combined with adjuvant treatment involving preoperative staged embolization and/or, less frequently, radiosurgery. In all patients treated with surgery alone, complete resection of AVM was achieved. A successful preoperative partial endovascular obliteration of AVM was obtained in 24 out of 27 more complex cases, with a zero mortality rate and a very low morbidity. Here, embolization was of a certain utility in the handling of deeper feeders and nidus excision, also facilitating intraoperative hemostasis. In three cases of residuals, radiosurgery was performed. In those patient treated with a combined approach, a good overall outcome, 0-2 modified Rankin Scale (mRS), was achieved in 25 cases. Preoperative embolization proved to be a reasonable option complementary to high-grade AVMs surgery, reducing the frequency of breakthrough hemorrhages, aiding the elimination of deep feeders, and making the nidus dissection easier.

Energy metabolism in glioblastoma stem cells: PPARα a metabolic adaptor to intratumoral microenvironment

Glioblastoma (GB), the most-common cancer in the adult brain, despite surgery and radio/ chemotherapy, is to date almost incurable. Many hypoxic tumors, including GB, show metabolic reprogramming to sustain uncontrolled proliferation, hypoxic conditions and angiogenesis. Peroxisome Proliferator-activated Receptors (PPAR), particularly the α isotype, have been involved in the control of energetic metabolism. Herein, we characterized patient-derived GB neurospheres focusing on their energetic metabolism and PPARα expression. Moreover, we used a specific PPARα antagonist and studied its effects on the energetic metabolism and cell proliferation/survival of GB stem cells. The results obtained demonstrate that tumor neurospheres are metabolically reprogrammed up-regulating glucose transporter, glucose uptake and glycogen and lipid storage, mainly under hypoxic culture conditions. Treatment with the PPARα antagonist GW6471 resulted in decreased cell proliferation and neurospheres formation. Therefore, PPARα antagonism arises as a potent new strategy as adjuvant to gold standard therapies for GB for counteracting recurrences and opening the way for pre-clinical trials for this class of compounds. When tumor neurospheres were grown in hypoxic conditions in the presence of different glucose concentrations, the most diluted one (0.25g/L) mimicking the real concentration present in the neurosphere core, PPARα increase/PPARγ decrease, increased proliferation and cholesterol content, decreased glycogen particles and LDs were observed. All these responses were reverted by the 72 h treatment with the PPARα antagonist.

Stemness Marker Detection in the Periphery of Glioblastoma and Ability of Glioblastoma to Generate Glioma Stem Cells: Clinical Correlations

BACKGROUND

Recent studies suggested glioma stem cells (GSCs) are key contributors to therapeutic resistance of glioblastoma multiforme (GBM) and are responsible for GBM recurrence.

METHODS

We characterized the phenotype of cancer cells in the core and periphery of 20 GBM tumors, correlating clinical outcome to the ability to form GSCs and distinguishing survival based on Ki-67 staining.

RESULTS

Similar levels of methylguanine-deoxyribonucleic acid methyltransferase were found in the core and periphery of GBM tumors, whereas Ki-67 was reduced in the periphery. Similar levels of stemness markers in the periphery and in the core of all GBM cultures were found. Only cells expressing >30% SOX2 levels were able to produce neurospheres. Immunophenotypic analysis showed higher levels of stemness markers in GSC cultures than in all GBM primary cultures. GSC in vitro production and coexpression of Ki-67 >5% negatively correlated with outcome.

CONCLUSIONS

Not all GBM cultures can generate GSCs, and this capacity is linked to >30% SOX2 levels. The ability to form spheres negatively correlated to survival, and the detection of >5% Ki-67 levels may be useful to identify patients at risk of disease progression. The presence of GSC-/SOX-2-/Ki-67- cells may be regarded as a new prognostic factor. The presence of stemness markers and methylguanine-deoxyribonucleic acid methyltransferase in the periphery of GBM tumors may be the reason for treatment failure and recurrence. Development of stem cell-targeted therapies and elaboration of more aggressive treatments represent an opportunity to eliminate the GBM source and the nidus of recurrence.

PPARα Antagonist AA452 Triggers Metabolic Reprogramming and Increases Sensitivity to Radiation Therapy in Human Glioblastoma Primary Cells

Glioblastoma (GB) is the most common cancer in the brain and with an increasing incidence. Despite major advances in the field, there is no curative therapy for GB to date. Many solid tumors, including GB, experienced metabolic reprogramming in order to sustain uncontrolled proliferation, hypoxic conditions, and angiogenesis. PPARs, member of the steroid hormone receptor superfamily, are particularly involved in the control of energetic metabolism, particularly lipid metabolism, which has been reported deregulated in gliomas. PPARα was previously indicated by us as a potential therapeutic target for this neoplasm, due to the malignancy grade dependency of its expression, being particularly abundant in GB. In this work, we used a new PPARα antagonist on patient-derived GB primary cells, with particular focus on the effects on lipid metabolism and response to radiotherapy. The results obtained demonstrated that blocking PPARα results in cell death induction, increase of radiosensitivity, and decrease of migration. Therefore, AA452 is proposed as a new adjuvant for the gold standard therapies for GB, opening the possibility for preclinical and clinical trials for this class of compounds. J. Cell. Physiol. 232: 1458-1466, 2017. © 2016 Wiley Periodicals, Inc.

Technical note: microdiscectomy and translaminar approach

Lumbar disk herniation (LDH) is a degenerative pathology. Although LDH generally occurs without migration of the fragment to the levels above or below, in 10% of the cases, this circumstance might happen. In these cases, the standard interlaminar approach, described by Caspar cannot be performed without laminotomies, interlaminectomies, or partial or total facetectomies. The translaminar approach is the only "tissue-sparing" technique viable in cases of cranially migrated LDH encroaching on the exiting nerve root in the preforaminal zones, for the levels above L2-L3, and in the preforaminal and foraminal zones, for the levels below L3-L4 (L5-S1 included, if a total microdiscectomy is unnecessary). This approach is more effective than the standard one, because it resolves the symptoms; it is associated with less postoperative pain and faster recovery times without the risk of iatrogenic instability, and it can also be used in cases with previous signs of radiographic instability. The possibility to spare the flavum ligament is one of the main advantages of this technique. For these reasons, the translaminar approach is a valid technique in terms of safety and efficacy. In this article the surgical technique will be extensively analyzed and the tips and tricks will be highlighted.

Third-generation percutaneous vertebral augmentation systems

Currently, there is no general consensus about the management of osteoporotic vertebral fractures (OVF). In the past, conservative treatment for at least one month was deemed appropriate for the majority of vertebral fractures. When pain persisted after conservative treatment, it was necessary to consider surgical interventions including: vertebroplasty for vertebral fractures with less than 30% loss of height of the affected vertebral body and kyphoplasty for vertebral fractures with greater than 30% loss of height. Currently, this type of treatment is not feasible. Herein we review the characteristics and methods of operation of three of the most common percutaneous vertebral augmentation systems (PVAS) for the treatment of OVF: Vertebral Body Stenting(®) (VBS), OsseoFix(®) and Spine Jack(®). VBS is a titanium device accompanied by a hydraulic (as opposed to mechanical) working system which allows a partial and not immediate possibility to control the opening of the device. On the other hand, OsseoFix(®) and Spine Jack(®) are accompanied by a mechanical working system which allows a progressive and controlled reduction of the vertebral fracture. Another important aspect to consider is the vertebral body height recovery. OsseoFix(®) has an indirect mechanism of action: the compaction of the trabecular bone causes an increase in the vertebral body height. Unlike the Vertebral Body Stenting(®) and Spine Jack(®), the OsseoFix(®) has no direct lift mechanism. Therefore, for these characteristics and for the force that this device is able to provide. In our opinion, Spine Jack(®) is the only device also suitable for the treatment OVF, traumatic fracture (recent, old or inveterate) and primary or secondary bone tumors.

Intraforaminal ozone therapy and particular side effects: preliminary results and early warning

BACKGROUND

The term "low back pain syndrome" represents a complex nosological entity. The therapeutic approach is often only symptomatic and not etiologic.

METHODS

Since 2013, 186 patients (97 males and 89 females, mean age 59.8 years) have undergone microsurgery for lumbar disc hernia or lumbar segmental stenosis. Among these patients, 23 had been previously treated with ozone therapy by the intraforaminal approach and 28 by intraforaminal steroid injections in other hospitals between 12 and 24 months before our clinical evaluation. These patients received 16 applications in an 8-week period (standard therapy).

RESULTS

During the surgery, many hard adhesions between the soft tissues and bony structures were unexpectedly discovered. In particular, it was noted that the root contracted and had firm adhesions to the dural sac and/or fragmented disc, which were difficult to resolve. These specific pathological patterns were observed only in the patients who received ozone injections by the intraforaminal approach. We did not find any pathological abnormalities in the patients who did not receive any injections or who received intraforaminal steroid injections. Thus, we could exclude that the tissue damage was due to the mechanical action of the needle.

CONCLUSION

It is important to assert that ozone therapy procedures can be associated with several major complications. Therefore, performing a revision of the guidelines and protocols for ozone therapy application is indispensable.

Patient outcomes following second surgery for recurrent glioblastoma

BACKGROUND

The most appropriate management of recurrent glioblastoma is still controversial. In particular, the role of surgery at recurrence remains uncertain.

PATIENTS & METHODS

From our Institutional data warehouse we analyzed 270 consecutive patients who received second surgery for recurrent glioblastoma, to assess survival after second surgery, and to evaluate prognostic factors.

RESULTS

Complete resection was found in 128 (47.4%) and partial resection in 142 patients (52.6%). Median survival from second surgery was 11.4 months (95% CI: 10.0-12.7). Multivariate analysis showed that age (p = 0.001), MGMT methylation (p = 0.021) and extent of surgery (p < 0.001) are associated with better survival.

CONCLUSION

A complete resection should be the goal for second resection and younger age and MGMT methylation status might be considered in the selection of patients.

Nucleolin antagonist triggers autophagic cell death in human glioblastoma primary cells and decreased in vivo tumor growth in orthotopic brain tumor model

Nucleolin (NCL) is highly expressed in several types of cancer and represents an interesting therapeutic target. It is expressed at the plasma membrane of tumor cells, a property which is being used as a marker for several human cancer including glioblastoma. In this study we investigated targeting NCL as a new therapeutic strategy for the treatment of this pathology. To explore this possibility, we studied the effect of an antagonist of NCL, the multivalent pseudopeptide N6L using primary culture of human glioblastoma cells. In this system, N6L inhibits cell growth with different sensitivity depending to NCL localization. Cell cycle analysis indicated that N6L-induced growth reduction was due to a block of the G1/S transition with down-regulation of the expression of cyclin D1 and B2. By monitoring autophagy markers such as p62 and LC3II, we demonstrate that autophagy is enhanced after N6L treatment. In addition, N6L-treatment of mice bearing tumor decreased in vivo tumor growth in orthotopic brain tumor model and increase mice survival. The results obtained indicated an anti-proliferative and pro-autophagic effect of N6L and point towards its possible use as adjuvant agent to the standard therapeutic protocols presently utilized for glioblastoma.

Immunophenotypic characterization of human glioblastoma stem cells: correlation with clinical outcome

Recently, glioma stem cells have been identified as the main cause of glioma propagation and recurrence and a number of several cell markers have been indicated as putative GSC markers. In the present work, a retrospective study to evaluate the prognostic potential of ability to generate GSCs in our series of 15 glioblastoma patients is described. β-tubulin III, nestin, CD133, GFAP, and SOX-2 marker expression, both in primary GBM cultures and in respective glioblastoma stem cells (GSCs), was evaluated by flow cytometric analysis. Our results demonstrated various expression levels of these markers in both cell cultures; of note, only those cells expressing SOX-2 at greater than 30% levels were able to produce in vitro neurospheres. Moreover, statistical analysis revealed that the GSCs generation negatively affected overall survival (OS) (P = 0.000) and progression-free survival (PFS) (P = 0.001). In addition, a very poor OS (P = 0.000) and PFS (P = 0.000) were observed among patients whose tumors expressed Ki67, evaluated by immunohistochemistry, and showed the ability to generate in vitro GSCs. Overall, the results suggest that in vitro GSCs generation associated to the expression of Ki67 and SOX-2 may be useful to identify patients at risk of disease progression.

The double tunnels technique: an alternative minimally invasive approach for carpal tunnel syndrome

OBJECT

The purpose of this study was to assess the effectiveness and safety of an alternative minimally invasive technique for the treatment of carpal tunnel syndrome (CTS).

METHODS

This was designed as a prospective, randomized, open-label, blinded end point evaluation (PROBE) study. The active comparison was double tunnels technique (DTT) (Group A, 110 patients) versus standard open decompression of the median nerve (control [Group B], 110 patients). Patient recruitment started in January 2011. The primary outcomes were the functional Boston Carpal Tunnel Syndrome Questionnaire (BCTSQ) scores and visual analog scale (VAS) scores for pain (pVAS) at Weeks 2 and 4, and at Months 3, 6, and 12. The secondary outcome was the aesthetics (aVAS) score at Weeks 2 and 4, and at Months 3, 6, and 12.

RESULTS

The Student t-test and ANOVA were used, and the results were considered statistically significant if the p value was ≤ 0.05 for continuous variables. The DTT is a tissue-sparing approach that allows the surgeon to limit the length of the incision (0.6 ± 0.05 cm) and to respect the palmar fascia and the subcutaneous tissue. Recovery from wrist pain, night pain, numbness, stiffness, and weakness was achieved more effectively and quickly compared with the standard approach. Better BCTSQ, pVAS, and aVAS scores were observed in Group A.

CONCLUSIONS

The DTT is a safe and effective approach for the treatment of CTS. This technique entails faster recovery times, better aesthetic outcomes, and lower risks of complications.

Microdiskectomy and translaminar approach: minimal invasiveness and flavum ligament preservation

Study Design Retrospective study. Objective The interlaminar approach represents the standard procedure for the surgical treatment of lumbar disk herniation (LDH). In the case of disk herniations in the "hidden zone," it could be necessary to perform laminotomies or laminectomies and partial or total facetectomies to remove the herniated fragment, thus leading to iatrogenic instability. The objective of the study is to evaluate the translaminar approach, in terms of the results, safety, and efficacy compared with the standard approach. Methods Since February 2010, 38 patients (26 men and 12 women; mean age 50.9 years, range 31 to 78 years) with LDH and migration into the hidden zone underwent a microdiskectomy by the translaminar approach. Using a micro-diamond dust-coated burr, a translaminar hole (8 ± 2 mm) was made, with subsequent exposure of the involved root and removal of the fragment. A clinical follow-up was performed at months 1, 3, 6, and 12 using the visual analog scale and the Oswestry Disability Index. All patients were evaluated according to the Spangfort score. Postoperative radiographic evaluations were done at 1, 6, and 12 months (dynamic radiographic studies done at 6 and 12 months). Results In over 60% of cases, L4-L5 was the involved disk. The visualization of the roots was successfully achieved through a translaminar approach. No laminotomies, laminectomies, or partial or total facetectomies were performed. The flavum ligament was always spared. A severe intraoperative bleeding episode occurred in 5% of the cases, due to involvement of the epidural veins, but it did not result in prolonged operative time (mean duration 60 ± 10 minutes). The patients showed a gradual resolution of the back pain and a progressive resolution of the radicular pain and the neurologic deficits. No sign of radiographic instability was documented during the follow-up. No infections, dural tears, or spinal cord injuries occurred. No revision surgery was performed. Conclusion The translaminar approach is the only tissue-sparing technique viable in case of cranially migrated LDH encroaching on the exiting nerve root in the preforaminal zones, for the levels above L2-L3, and in the preforaminal and foraminal zones, for the levels below L3-L4 (L5-S1 included, if a total microdiskectomy is not necessary). The possibility to spare the flavum ligament is one of the main advantages of this technique. According to our experience, the translaminar approach is an effective and safe alternative minimally invasive surgical option.