The Integration of 3D Virtual Reality and 3D Printing Technology as Innovative Approaches to Preoperative Planning in Neuro-Oncology.

Our study explores the integration of three-dimensional (3D) virtual reality (VR) and 3D printing in neurosurgical preoperative planning. Traditionally, surgeons relied on two-dimensional (2D) imaging for complex neuroanatomy analyses, requiring significant mental visualization. Fortunately, nowadays advanced technology enables the creation of detailed 3D models from patient scans, utilizing different software. Afterwards, these models can be experienced through VR systems, offering comprehensive preoperative rehearsal opportunities. Additionally, 3D models can be 3D printed for hands-on training, therefore enhancing surgical preparedness. This technological integration transforms the paradigm of neurosurgical planning, ensuring safer procedures.

Microneurosurgical training in the anatomical specimen: A structured plan for endoscopic and microsurgical skull base training during the residency.

BACKGROUND AND OBJECTIVE: The development of a high level of competence and technical proficiency is one of the main objectives of any neurosurgical training program. Due to many factors, this progressive skill development can be complex during the residency. Despite its high cost and infrastructure requirements, there is renewed interest regarding the role of anatomy labs. The study and dissection of the human cadaver has been the environment where many surgeons have developed the necessary skills for microneurosurgery. We propose a structured endoscopic and microsurgical training dissection program to enable residents to maximize the benefits of their training in the lab. MATERIAL AND METHODS: During the months of September, October and November 2021, a stay was done at the Microneurosurgery and Skull Base Laboratory of the Miguel Hernández University of Alicante. A total of 2 specimens were used. The first specimen underwent a first endoscopic endonasal dissection phase. After completing the endonasal part, a set of incisions were made to perform the transcranial part. In the second specimen, the transcranial part was performed first, leaving the endonasal endoscopic work for the last phase. RESULTS: The results of the dissection program are presented. During the endonasal endoscopic phase, the transsphenoidal approach to the sella was simulated while focusing on the extended approaches in the sagittal plane. During the transcranial phase, right and left anterolateral approaches, a left anterior transcallosal interhemispheric approach, a left transcondylar posterolateral approach and a combined right lateral approach were performed. CONCLUSIONS: The structured dissection of the specimen allowed both endonasal endoscopic and transcranial microsurgical training in the same specimen. This design facilitated the realization of the core skull base approaches in the same specimen. According to our initial experience, we believe that developing common dissection programs is a powerful tool to maximize the results of our residents' laboratory training.

Robot-assisted implantation of a microelectrode array in the occipital lobe as a visual prosthesis: technical note.

The prospect of direct interaction between the brain and computers has been investigated in recent decades, revealing several potential applications. One of these is sight restoration in profoundly blind people, which is based on the ability to elicit visual perceptions while directly stimulating the occipital cortex. Technological innovation has led to the development of microelectrodes implantable on the brain surface. The feasibility of implanting a microelectrode on the visual cortex has already been shown in animals, with promising results. Current research has focused on the implantation of microelectrodes into the occipital brain of blind volunteers. The technique raises several technical challenges. In this technical note, the authors suggest a safe and effective approach for robot-assisted implantation of microelectrodes in the occipital lobe for sight restoration.

Clinical and anatomical analysis of the epileptogenic spread patterns in focal cortical dysplasia patients.

Background: Focal cortical dysplasia (FCD) is one of the main causes of intractable epilepsy, which is amendable by surgery. During the surgical management of FCD, the understanding of its epileptogenic foci, interconnections, and spreading pathways is crucial for attaining a good postoperative seizure free outcome. Methods: We retrospectively evaluated 54 FCD patients operated in Federal Center of Neurosurgery, Tyumen, Russia. The electroencephalogram findings were correlated to the involved brain anatomical areas. Subsequently, we analyzed the main white matter tracts implicated during the epileptogenic spreading in some representative cases. We prepared 10 human hemispheres using Klinger's method and dissected them through the fiber dissection technique. Results: The clinical results were displayed and the main white matter tracts implicated in the seizure spread were described in 10 patients. Respective FCD foci, interconnections, and ectopic epileptogenic areas in each patient were discussed. Conclusion: A strong understanding of the main implicated tracts in epileptogenic spread in FCD patient remains cardinal for neurosurgeons dealing with epilepsy. To achieve meaningful seizure freedom, despite the focal lesion resection, the interconnections and tracts should be understood and somehow disconnected to stop the spreading.

Dynamic Lateral Semisitting Position for Supracerebellar Approaches: Technical Note and Case Series.

BACKGROUND: It has always been a matter of debate which position is ideal for the supracerebellar approach. The risk of venous air embolism (VAE) is the major deterrent for surgeons and anesthesiologists, despite the fact that sitting and semisitting positions are commonly used in these operations. OBJECTIVE: To demonstrate a reduction on the risk of VAE and tension pneumocephalus throughout the operation period while taking advantages of the semisitting position. METHODS: In this study, 11 patients with various diagnoses were operated in our department using the supracerebellar approach in the dynamic lateral semisitting position. We used end-tidal carbon dioxide and arterial blood pressure monitoring to detect venous air embolism. RESULTS: None of the patients had clinically significant VAE in this study. No tension pneumocephalus or major complications were observed. All the patients were extubated safely after surgery. CONCLUSION: The ideal position, with which to apply the supracerebellar approach, is still a challenge. In our study, we presented an alternative position that has advantages of the sitting and semisitting positions with a lower risk of venous air embolism.

Predictive model of resection in endoscopic endonasal approach for pituitary adenomas based on anatomical limits.

INTRODUCTION: The aim of this project is to study several anatomical-radiological features of pituitary adenomas obtained from preoperative radiological images and to analyze their relationship with the extent of resection achieved through the endoscopic endonasal approach. The second objective was to create a prediction model of the extent of resection. MATERIAL AND METHODS: We retrospectively evaluated 105 patients. Tumor volume, Knosp grade, suprasellar-diaphragm coefficient and invasion of the posterior compartment have been analyzed. The extent of resection was assessed by analyzing the postoperative magnetic resonance. We created the predictive scale using statistically independent variables. RESULTS: When each of the variables has been studied individually, a statistically significant value of all of them is appreciated to obtain a complete resection. However, only the Knosp grade and the suprasellar-diaphragm coefficient had a statistically significant value as independent variables. The sum of the Odds Ratio obtained from the Knosp scale, and the suprasellar-diaphragm coefficient gives the probability of complete resection. A new set of cases was employed to validate the scale. CONCLUSIONS: The cavernous sinus invasion and the newly designed suprasellar diaphragm coefficient are directly related to the extent of resection in pituitary adenoma surgery performed by a transellar endoscopic approach. Moreover, based on both radiologic factors, a predictive scale may predict the probability of complete resection in a series of patients.

Micromirrors in Neurosurgery: Technical Overview and Benefits Assessment.

AIM: To weight the benefits and limitations of intraoperative use of micromirrors in neurosurgery. MATERIAL AND METHODS: Surgical cases where micromirrors were employed were retrospectively selected from the surgical database of five different surgeons in different hospitals. Complications directly attributable to the micromirrors were assessed intraoperatively and confirmed with postoperative neuroimaging studies. RESULTS: Fourteen patients were selected. The site of the lesion was as follows: posterior fossa (43%), frontal lobe (22%), temporal lobe (14%), parietal lobe (7%), insula (7%), and basal ganglia (7%). Five tumors (35%) were gliomas, 3 (21%) epidermoid, and 3 (21 %) supratentorial metastases. Two patients underwent microvascular decompression for neurovascular conflict, and 1 harbored a brain arteriovenous malformation. A gross total resection was achieved in all the tumors and the AVM, while an effective decompression was successfully performed in both patients with conflict. No complications directly attributable to the use of the micromirror occurred. A relatively easy learning curve was noted. CONCLUSION: Micromirrors proved to be useful in enhancing the visualization of neurovascular structures and pathology residuals within deep-seated surgical fields without the need for fixed brain retraction. Their cost-effectiveness and easy learning curve constitute solid reasons for advocating a revitalization of this ?old but gold? tool in neurosurgery.

Central quadrantotomy for intractable childhood epilepsy: operative technique and functional neuroanatomy.

Refractory subhemispheric epilepsy has been traditionally treated by resection. The last few decades have seen the emergence of disconnective techniques, for both hemispheric and subhemispheric disease. The aim of this study was to describe the technique for a disconnective surgery for large epileptogenic lesions involving the central (perirolandic cortices), parietal, and occipital lobes. This junctional cortex within the hemisphere (in contrast to anterior and posterior quadrantotomies) presents unique challenges when contemplating a complete disconnection of the region. The surgical technique is achieved through six distinct steps: fronto-central, inferior frontoparietal, lateral temporo-occipital, medial frontal, basal temporo-occipital, and posterior parasagittal callosal disconnections. The functional neuroanatomy of each step is described, along with cadaveric dissections. The authors describe this technique and include a case description of a young girl who presented with childhood-onset intractable epilepsy associated with cognitive stagnation. The postoperative seizure outcome in this patient remains excellent at 2 years' follow-up, with gains in cognition and behavior. Excellent seizure outcomes can be achieved if the network encompassing the entire epileptogenic cortex is disconnected while ensuring preservation of fiber systems that link functionally eloquent uninvolved cortices adjacent to the central quadrant.

Working in low- and middle-income countries: Learning from each other.

•Barriers may limit LMICs-HICs collaborations: infrastructure, equipment's lack/inadequacy, political issues, brain drain.•Local training is crucial for universal health coverage; several activities are headed by Global Neurosurgery organisations.•The â€‹EANS Global and Humanitarian Neurosurgery Committee aims to become a gateway for partnerships between HICs and LMICs.

A Frontal Route to Middle and Posterior Cranial Fossa: Quantitative Study for the Lateral Transorbital Endoscopic Approach and Comparison with the Subtemporal Approach.

BACKGROUND: Skull base lesions within the middle cranial fossa (MCF) remain challenging. Recent reports suggest that transorbital endoscopic approaches (TOEAs) might be particularly suitable to access the MCF and expose the lateral wall of the cavernous sinus and the Meckel's cave. METHODS: The present study was developed to compare the nuances of the subtemporal approach (STA) with those of the lateral TOEA (LTOEA) to the MCF and posterior cranial fossa (PCF) in cadaveric specimens. After orbital craniectomy, interdural opening of the cavernous sinus lateral wall (CSlw), exposure of the Gasserian ganglion, and extradural elevation of the temporal lobe was performed. Next, anterior endoscopic petrosectomy was performed and the PCF was accessed. We quantitatively analyzed and compared the angles of attack and distances between LTOEA and STA to different structures at the CSlw, petrous apex (PA), and PCF. RESULTS: Cadaveric dissection through the LTOEA completely exposed the CSlw and PA. LTOA exhibited larger distances than the STA to all targets. Importantly, these differences were greater at the PA and its surrounding key anatomic landmarks. The horizontal and vertical angles of attack allowed by the LTOA were smaller both for the CSlw and PA. However, these differences were not significant for the vertical angle of attack at the CSlw. CONCLUSIONS: LTOEA provides a direct ventral route to the medial aspect of MCF, PA, and PCF. Although TOEAs are versatile approaches, the unfamiliar surgical anatomy and limited instrument maneuverability demand extensive cadaveric dissection before moving to the clinical setting.

Three-Dimensional Reconstruction of the Sphenoid Sinus Anatomy for Presurgical Planning with Free OSIRIX Software.

Background A preoperative three-dimensional (3D) surgical field understanding remains a key factor to achieve safer endonasal transsphenoidal endoscopic approaches (ETSE). The aim of this article is to describe how we can get a reliable 3D sphenoidal anatomical reconstruction for surgical planning by using a user-friendly, accurate, and free image software. Methods Free computer software (OSIRIX Medical Imaging Software) was used to create in a personal computer a three-dimensional (3D) reconstruction of the sphenoid sinus (SS) based on head computed tomography angiographies (CTAs) from a series of 67 patients who were operated for sellar tumors during a 4-year period (March 2016 to March 2020). The aim of the 3D reconstruction with OSIRIX was to reveal preoperatively the most important intrasphenoidal structures seen from the endonasal point of view. Results The intraoperative visible sphenoidal structures were previously recognized in the virtual 3D reconstructed image with 100% of specificity (SP) and positive predictive value. The OSIRIX view by using region of interest points allowed us to see preoperatively the internal carotid artery parasellar course even in those cases in which it was hidden by bone or tumor. Moreover, the 3D reconstruction was able to provide a clear differentiation between the tumor and the pituitary gland when both structures were in contact with the sellar floor. Conclusion Our experience with the OSIRIX software from CTA as preoperative planning for endonasal pituitary surgery was valuable, because it gave us access in simple way to a free and reliable 3D image of the SS.

Middle fossa approach for a facial nerve schwannoma: how I do it.

BACKGROUND: Facial nerve schwannomas can extend to the middle fossa or the cerebellopontine angle through the labyrinthine and cisternal segments of the facial nerve. The middle fossa approach (MFA) and its extensions provide a wide approach to deal with a large variety of lesions located in the middle and posterior cranial fossa junction. METHODS: We describe the MFA along with its advantages and limitations to treat a facial nerve schwannoma involving the middle and posterior cranial fossa. CONCLUSIONS: The MFA is a well-established route to surgically deal with tumors located in and around the proximal four segments of the facial nerve.

Cadaveric White Matter Dissection Study of the Telencephalic Flexure: Surgical Implications.

Neurosurgery has traditionally been overtly focused on the study of anatomy and functions of cortical areas with microsurgical techniques aimed at preserving eloquent cortices. In the last two decades, there has been ever-increasing data emerging from advances in neuroimaging (principally diffusion tensor imaging) and clinical studies (principally from awake surgeries) that point to the important contribution of white matter tracts (WMT) that influence neurological function as part of a brain network. Major scientific consortiums worldwide, currently working on this human brain connectome, are providing evidence that is dramatically altering the manner in which we view neurosurgical procedures. The development of the telencephalic flexure, a major landmark during the human embryogenesis of the central nervous system (CNS), severely affects the cortical/subcortical anatomy in and around the sylvian fissure and thus the different interacting brain networks. Indeed, the telencephalic flexure modifies the anatomy of the human brain with the more posterior areas becoming ventral and lateral and associative fibers connecting the anterior areas with the previous posterior ones follow the flexure, thus becoming semicircular. In these areas, the projection, association, and commissural fibers intermingle with some WMT remaining curved and others longitudinal. Essentially the ultimate shape and location of these tracts are determined by the development of the telencephalic flexure. Five adult human brains were dissected (medial to lateral and lateral to medial) with a view to describing this intricate anatomy. To better understand the 3D orientation of the WMT of the region we have correlated the cadaveric data with the anatomy presented in the literature of the flexure during human neuro-embryogenesis in addition to cross-species comparisons of the flexure. The precise definition of the connectome of the telencephalic flexure is primordial during glioma surgery and for disconnective epilepsy surgery in this region.

Optic Foraminotomy for Clipping of Superior Carotid-Ophthalmic Aneurysms.

Background: Carotid-ophthalmic aneurysms usually cause visual problems. Its surgical treatment is challenging because of its anatomically close relations to the optic nerve, carotid artery, ophthalmic artery, anterior clinoid process, and cavernous sinus, which hinder direct access. Despite recent technical advancements enabling risk reduction of this complication, postoperative deterioration of visual function remains a significant problem. Therefore, the goal of preserving and/or improving the visual outcome persists as a paramount concern. Objective: We propose optic foraminotomy as an alternative microsurgical technique for dorsal carotid-ophthalmic aneurysms clipping. As a secondary objective, the step by step of that technique and its benefits are compared to the current approach of anterior clinoidectomy. Methods: We present as an example two patients with superior carotid-ophthalmic aneurysms in which the standard pterional craniotomy, transsylvian approach, and optic foraminotomy were performed. Surgical techniques are presented and discussed in detail with the use of skull base dissections, microsurgical images, and original drawings. Results: Extensive opening of the optic canal and optic nerve sheath was successfully achieved in all patients allowing a working angle with the carotid artery for correct visualization of the aneurysm and further clipping. Significant visual acuity improvement occurred in both patients because of decompression of the optic nerve. Conclusion: Optic foraminotomy is an easy and recommended technique for exposing and treating superior carotid-ophthalmic aneurysms and allowing optic nerve decompression during the first stages of the procedure. It shows several advantages over the current anterior clinoidectomy technique regarding surgical exposure and facilitating visual improvement.

How I do it: paramedian supracerebellar transtentorial approach for a temporomesial glioma.

BACKGROUND: Classical approaches to the temporomesial region (TMR) include transtemporal, transylvian, or subtemporal. The supracerebellar infratentorial, initially developed to access dorsolateral cavernomas, has of late shown its versatility to access areas around the central core. The TMR is one such area that can be accessed through this approach with the addition of a tentorial incision. METHOD: The paramedian supracerebellar transtentorial approach (PSCTA) is described along with its advantages and limits compared to other approaches to treat TMR gliomas. CONCLUSION: The PSCTA offers a basal panoramic view of the TMR without the need of retraction, cortical incision, and white matter transgression.

Utility of indocyanine green in the detection of radiologically silent hemangioblastomas: case report.

Hemangioblastomas (HBs) are rare, benign, hypervascularized tumors. Fluorescent imaging with indocyanine green (ICG) can visualize tumor angioarchitecture. The authors report a case of multiple HBs involving two radiologically silent lesions only detected intraoperatively by ICG fluorescence. A 26-year-old woman presented with a cystic cerebellar mass on the tentorial surface of the left cerebellar hemisphere on MRI. A left paramedian suboccipital approach was performed to remove the mural nodule with the aid of ICG injection. The first injection, applied just prior to removing the nodule, highlighted the tumor and vessels. After resection, two new lesions, invisible on the preoperative MRI, surprisingly enhanced on fluorescent imaging 35 minutes after the ICG bolus. Both silent lesions were removed. Histological analysis of all three lesions revealed they were positive for HB. The main goal of this report is to hypothesize possible explanations about the mechanism that led to the behavior of the two silent lesions. Intraoperative ICG videoangiography was useful to understand the 3D angioarchitecture and HB flow patterns to perform a safe and complete resection in this case. Understanding the HB ultrastructure and pathophysiological mechanisms, in conjunction with the properties of ICG, may expand potential applications for their diagnosis and future treatments.

Extreme Lateral Supracerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature.

OBJECTIVE: The extreme lateral supracerebellar infratentorial (ELSI) approach has the potential to access several distinct anatomical regions that are otherwise difficult to reach. We have illustrated the surgical anatomy through cadaveric dissections and provided an extensive review of the literature to highlight the versatility of this approach, its limits, and comparisons with alternative approaches. METHODS: The surgical anatomy of the ELSI has been described using 1 adult-injected cadaveric head. Formalized noninjected brain specimens were also dissected to describe the brain parenchymal anatomy of the region. An extensive review of the literature was performed according to each targeted anatomical region. Illustrative cases are also presented. RESULTS: The ELSI approach allows for wide exposure of the middle and posterolateral incisural spaces with direct access to centrally located intra-axial structures such as the splenium, pulvinar, brainstem, and mesial temporal lobe. In addition, for skull base extra-axial tumors such as petroclival meningiomas, the ELSI approach represents a rapid and adequate method of access without the use of extensive skull base approaches. CONCLUSIONS: The ELSI approach represents one of the most versatile approaches with respect to its ability to address several anatomical regions centered at the posterior and middle incisural spaces. For intra-axial pathologies, the approach allows for access to the central core of the brain with several advantages compared with alternate approaches that frequently involve significant brain retraction and cortical incisions. In specific cases of skull base lesions, the ELSI approach is an elegant alternative to traditionally used skull base approaches, thereby avoiding approach-related morbidity.

Unilateral prefrontal lobotomy for epilepsy: technique and surgical anatomy.

OBJECTIVE: Surgery for frontal lobe epilepsy remains a challenge because of the variable seizure outcomes after surgery. Disconnective procedures are increasingly applied to isolate the epileptogenic focus and avoid complications related to extensive brain resection. Previously, the authors described the anterior quadrant disconnection procedure to treat large frontal lobe lesions extending up to but not involving the primary motor cortex. In this article, they describe a surgical technique for unilateral disconnection of the prefrontal cortex, while providing an accurate description of the surgical and functional anatomy of this disconnective procedure. METHODS: The authors report the surgical treatment of a 5-month-old boy who presented with refractory epilepsy due to extensive cortical dysplasia of the left prefrontal lobe. In addition, with the aim of both describing the subcortical intrinsic anatomy and illustrating the different connections between the prefrontal lobe and the rest of the brain, the authors dissected six human cadaveric brain hemispheres. These dissections were performed from lateral to medial and from medial to lateral to reveal the various tracts sectioned during the three different steps in the surgery, namely the intrafrontal disconnection, anterior callosotomy, and frontobasal disconnection. RESULTS: The first step of the dissection involves cutting the U-fibers. During the anterior intrafrontal disconnection, the superior longitudinal fasciculus in the depth of the middle frontal gyrus, the uncinate fasciculus, and the inferior frontooccipital fasciculus in the depth of the inferior frontal gyrus at the level of the anterior insular point are visualized and sectioned, followed by sectioning of the anterior limb of the internal capsule. Once the frontal horn is reached, the anterior callosotomy can be performed to disconnect the genu and the rostrum of the corpus callosum. The intrafrontal disconnection is deepened toward the falx, and at the medial surface, the cingulum is sectioned. The frontobasal disconnection involves cutting the anterior limb of the anterior commissure. CONCLUSIONS: This technique allows selective isolation of the epileptogenic focus located in the prefrontal lobe to avoid secondary propagation. Understanding the surface and white matter fiber anatomy is essential to safely perform the procedure and obtain a favorable seizure outcome.

Anterior peri-insular quadrantotomy: a cadaveric white matter dissection study.

OBJECTIVE: Anterior quadrant disconnection represents a safe surgical option in well-selected pediatric patients with a large frontal lobe lesion anterior to the motor cortex. The understanding of the anatomy of the white matter tracts connecting the frontal lobe with the rest of the cerebrum forms the basis of a safe and successful disconnective surgery. The authors explored and illustrated the relevant white matter tracts sectioned during each surgical step using fiber dissection techniques. METHODS: Five human cadaveric hemispheres were dissected to illustrate the frontal connections in the 3 planes. The dissections were performed from lateral to medial, medial to lateral, and ventral to dorsal to describe the various tracts sectioned during the 4 steps of this surgery, namely the anterior suprainsular window, intrafrontal disconnection, anterior callosotomy, and frontobasal disconnection. RESULTS: At the beginning of each surgical step, the U fibers were cut. During the anterior suprainsular window, the superior longitudinal fasciculus (SLF), the uncinate fasciculus, and the inferior fronto-occipital fasciculus (IFOF) were visualized and sectioned, followed by sectioning of the anterior limb of the internal capsule. During the intrafrontal disconnection, the SLF was cut, along with the corona radiata. At the medial surface the cingulum was sectioned. The anterior callosotomy disconnected the anterior third of the body of the callosum, the genu, and the rostrum. The frontobasal disconnection addressed the last remaining fibers connecting the frontal lobe with the rest of the hemisphere, namely the anterior limb of the anterior commissure. CONCLUSIONS: The anterior peri-insular quadrantotomy aims at effectively treating children with large lesions of the frontal lobe anterior to the motor cortex. A precise understanding of the gyral anatomy of this lobe along with the several white matter connections is crucial to avoid motor complications and to ensure complete disconnection.

Endonasal Endoscopic and Transoral Approaches to the Craniovertebral Junction and the Clival Region: A Comparative Anatomical Study.

OBJECTIVE: Anterior craniovertebral junction (CVJ) surgery has continued to be one of the most debated neurosurgical topics. The transoral approach (TOA) has been considered the choice for this region. However, it has some limitations and a not negligible degree of surgery-related morbidity. With the advent of endoscopy, the endoscopic endonasal approach (EEA) was developed, which minimized morbidity and improved exposure. To the best of our knowledge, despite the extensive reported data, a comparative anatomical study has not been performed and no definitive consensus has been reached on the indications for both approaches. METHODS: We compared the TOA and EEA to the CVJ using the previously described operability score (OS), calculated at 4 different targets: the C1 tubercle (C1), the lowest exposed point of the odontoid process (C2), the basion (BS) and the middle clivus (MC). The higher the OS for the selected targets, the more favorable the approach. RESULTS: The TOA had higher OSs at the MC, C1, and C2 targets, and the EEA showed greater OSs at MC and C1. The TOA and EEA had similar OSs at the BS. These results have shown that the OS is more favorable at C1-C2 using the TOA and the OSs at the MC and BS were similar. CONCLUSIONS: The OS is an effective method to compare surgical approaches. The present study demonstrated the maximal exposure capability of the 2 approaches. The TOA seemed to be superior for lower targets and the EEA for upper targets. Because of the strong variability in the CVJ anatomy and pathological features, we suggest considering the OS as a further tool to better define the best surgical approach.