Alberto Di Somma

Endoscopic Anatomy of the Skull Base Explored Through the Nose

OBJECTIVE Different surgical approaches have been used over the years in order to access skull base. The endoscopic endonasal approach represents a direct and minimally invasive approach to the suprasellar, retrosellar, and retroclival space, with the advantage of avoid brain retraction and visualize safely and effectively the surgical target. The present contribution aims to provide anatomical details of the skull base as seen from below (i.e., via an endoscopic endonasal approach). METHODS Five human cadaver heads were dissected. The anatomical neurovascular structures within the skull base were visualized and carefully described from an endoscopic endonasal view. The advantages and limitations of the endoscopic endonasal route were discussed as well. RESULTS The entire skull base region, as seen from the endoscopic endonasal viewpoint, has been divided in 4 main regions: anterior skull base, middle skull base, posterior skull base and parasellar area. CONCLUSION The development of endoscopic techniques has opened different perspectives over the skull base surgery. Endonasal surgery provides access to a wide range of skull base lesions via a natural surgical corridor (i.e., the nasal cavities).

Extended Endoscopic Endonasal Approaches for Cerebral Aneurysms: Anatomical, Virtual Reality and Morphometric Study

Introduction. The purpose of the present contribution is to perform a detailed anatomic and virtual reality three-dimensional stereoscopic study in order to test the effectiveness of the extended endoscopic endonasal approaches for selected anterior and posterior circulation aneurysms. Methods. The study was divided in two main steps: (1) simulation step, using a dedicated Virtual Reality System (Dextroscope, Volume Interactions); (2) dissection step, in which the feasibility to reach specific vascular territory via the nose was verified in the anatomical laboratory. Results. Good visualization and proximal and distal vascular control of the main midline anterior and posterior circulation territory were achieved during the simulation step as well as in the dissection step (anterior communicating complex, internal carotid, ophthalmic, superior hypophyseal, posterior cerebral and posterior communicating, basilar, superior cerebellar, anterior inferior cerebellar, vertebral, and posterior inferior cerebellar arteries). Conclusion. The present contribution is intended as strictly anatomic study in which we highlighted some specific anterior and posterior circulation aneurysms that can be reached via the nose. For clinical applications of these approaches, some relevant complications, mainly related to the endonasal route, such as proximal and distal vascular control, major arterial bleeding, postoperative cerebrospinal fluid leak, and olfactory disturbances must be considered.

Extended Endoscopic Endonasal Approach to the Third Ventricle: Multimodal Anatomical Study with Surgical Implications

INTRODUCTION A certain interest for the extended endoscopic endonasal approach for the management of sellar-suprasellar lesions extending inside the third ventricle has been growing in recent years. The aim of this anatomical study was to evaluate the possibilities in terms of exposure and access to the different areas of the third ventricle, with the endoscopic endonasal technique, as compared with the microscopic or endoscopic view provided via different transcranial approaches. The advantages and limitations of both surgical pathways were analyzed. MATERIALS AND METHODS Ten human cadaver heads were dissected. In order to standardize the comparison between the endonasal and the transcranial routes, the third ventricle cavity has been divided into four areas by means of two ideal planes, one passing through the optic chiasm and the interthalamic commissure and one passing through the posterior edge of the foramen of Monro and the interthalamic commissure. Accordingly, two anterior (infundibular and foraminal) and two posterior (mesencephalic and tectal) areas have been defined. RESULTS The endoscopic endonasal approach allows for exploration and surgical maneuverability, especially in the anterior areas of the third ventricle. In the infundibular and foraminal areas the surgical maneuverability seems to be better as compared with that obtained inside the mesencephalic region, while via the endonasal route the tectal area could not be reached. In particular, the infundibular area can be explored either passing through the lamina terminalis or via the tuber cinereum; this latter trajectory enables visualization of the foramina of Monro and the floor of the third ventricle up to the pineal recess. CONCLUSION This anatomical study shows that the lamina terminalis and, above all, the tuber cinereum represent two safe entry points defining possible surgical corridors to be considered for the extended endoscopic endonasal approach to the third ventricle.

Rerum magistra experientia est: The Evolution of Modern Endoscopic Endonasal Skull Base Surgery and Reconstruction Techniques

istorically, surgical management of suprasellar lesions has been done by different transcranial approaches H including the subfrontal, frontolateral, and pterional routes. Nevertheless, in the past decades, the evolution of the transsphenoidal technique and the technological progress has favored the introduction and diffusion of the extended transsphenoidal approaches to the skull base. This was first described by Weiss (19), creating a paradigm in transsphenoidal surgery, with opening a new corridor to the suprasellar space. The transtuberculum-transplanum approach provides a direct route to the sellar suprasellar area, ensuring unrivalled visualization of the undersurface of the optic chiasm, third ventricle, pituitary stalk, and hypothalamus. The close visualization of the infrachiasmatic perforators from the carotid, the basilar, the posterior cerebral, and the posterior communicating arteries ensure a direct bimanual tumor dissection of critical neurovascular structures. Finally, the transtuberculum-transplanum pathway provides a direct midline and minimally invasive approach to the suprasellar region, without any brain retraction.

Essential role of ultrastructural examination for spindle cell oncocytoma: Case report of a rare neoplasm and review of the literature

ABSTRACT Spindle cell oncocytoma (SCO) is an extremely rare neoplasm of the sellar region recognized as a distinct benign histopathological subtype of pituitary tumors in the 2007 World Health Organization classification of tumors of the central nervous system. The morphology of its neoplastic cells (spindle cells and granular eosinophilic cytoplasm) is common to several other lesions so that immunohistochemistry, together with ultrastructural examination, becomes essential in solving this differential diagnosis. Despite being labeled as benign, recurrence is described. Herein, we report a case of SCO in a 77-year-old man and discuss the diagnostic difficulties, ultrastructural aspects, and prognostic factors.

Surgical clipping of a dissecting aneurysm of the precommunicating segment of the anterior cerebral artery: a case report and review of the literature.

IntroductionDissecting aneurysms of the cerebral arteries are uncommon vascular malformations. Neurosurgical treatment remains critical in the management of patients with such vascular pathologies.Case presentationA 20-year-old Caucasian woman presented with a sudden onset of severe headache and loss of consciousness. Computed tomography revealed diffuse subarachnoid hemorrhage, while a computed tomography disclosed a dissecting aneurysm of the precommunicating segment of the right anterior cerebral artery. Cerebral carotid angiography confirmed the presence of the dissecting aneurysm. Due to the peculiar anatomic configuration, endovascular treatment was excluded and surgery was selected. As the left circulation perfused both postcommunicating segments of the anterior cerebral artery and the distal right precommunicating segment was hypoplastic, direct clipping of the right precommunicating segment, close to its origin from the internal carotid artery, was carried out. She recovered after surgery and a late angiography showed the correct positioning of the clip, with regular perfusion of both right and left postcommunicating segments.ConclusionsThe management of dissecting aneurysms of the cerebral arteries is still controversial. With this report we highlight a possible neurosurgical option among therapeutic strategies for these uncommon vascular lesions.

The “extended” endoscopic endonasal approach for the removal of a mixed intrasuprasellar germinoma: Technical case report

Background: Intracranial germ cell tumors (GCTs) represent less than 5% of pediatric brain tumors. Neurosurgical treatment remains essential in the management of patients with intracranial nongerminomatous GCT. Case Description: A 12-year-old girl presented with clinical features of neurohypophyseal dysfunction and rapidly progressive visual worsening. Magnetic resonance imaging (MRI) showed a lesion arising from the sella with a significant suprasellar component, compressing the optic chiasm and extending into the third ventricle. The tumor was removed via an endoscopic endonasal transtuberculum-transplanum approach and the histology revealed a mixed germinoma. In the postoperative course, a conspicuous improvement of visual function was observed; an early postoperative MRI showed near-total removal of the lesion. The patient was referred to pediatric oncologist for the adjunctive chemotherapy and radiotherapy. Conclusions: The management of primary intracranial sellar and suprasellar germinomas still remains controversial. With this report we highlighted another possible surgical option among therapeutic strategies for these highly malignant tumors.

Surgical Approaches: Introduction and Outcomes

Abstract Craniopharyngiomas account for 1.2 to 4.6% of all intracranial tumors, and were first described in 1857 by Friedrich Albert von Zenker. They exist as two subtypes, namely adamantinomatous and papillary, with the former occurring in children and adults, but the form is seen almost exclusively in adults. Craniopharyngiomas involve the sella and parasellar areas and can recur even after radical resection. Over the years, several authors have defined classifications for craniopharyngiomas in terms of their growth path and the surgical route used. Fronto-temporal and transsphenoidal approaches are used, with the aid of the microscope and endoscope. Radiation treatment is usually reserved for residual or recurrent craniopharyngiomas. The outcome of primary surgery for craniopharyngiomas is affected by different factors such as age, clinical conditions, and previous treatment. Visual and endocrinological complications may persist.

Optic Nerve Atrophy Due to Long-Standing Compression by Planum Sphenoidale Meningioma

PURPOSE In this study we report an uncommon endoscopic endonasal image of an atrophic optic nerve as seen after surgical removal of a suprasellar meningioma. The peculiarity of this case is the long-lasting underestimated ocular symptomatology of the patient who reported a 15-year history of impairment of vision on her left eye. METHODS A 51-year-old woman was admitted to our hospital complaining of a 15-year history of impairment of vision on her left eye. After making serendipitously the diagnosis of a suprasellar mass, we performed endoscopic endonasal surgery. RESULTS The tumor was reached from below and removed safely, without manipulation of the optic pathways. At the end of tumor removal, the impressive left optic nerve atrophy due to enduring local tumor compression was visualized. CONCLUSIONS To the best of our knowledge, no endoscopic endonasal image with such features has been provided in the pertinent literature. Possibly, this contribution will help identify damaged optic nerves during endoscopic endonasal surgery.

Refining the anatomic boundaries of the endoscopic endonasal transpterygoid approach: the “VELPPHA area” concept

OBJECTIVEThe endoscopic endonasal transpterygoid route has been widely evaluated in cadavers, and it is currently used during surgery for specific diseases involving the lateral skull base. Identification of the petrous segment of the internal carotid artery (ICA) is a key step during this approach, and the vidian nerve (VN) has been described as a principal landmark for safe endonasal localization of the petrous ICA at the level of the foramen lacerum. However, the relationship of the VN to the ICA at this level is complex as well as variable and has not been described in the pertinent literature. Accordingly, the authors undertook this purely anatomical study to detail and quantify the peri-lacerum anatomy as seen via an endoscopic endonasal transpterygoid pathway.METHODSEight human anatomical specimens (16 sides) were dissected endonasally under direct endoscopic visualization. Anatomical landmarks of the VN and the posterior end of the vidian canal (VC) during the endoscopic endonasal transpterygoid approach were described, quantitative anatomical data were compiled, and a schematic classification of the most relevant structures encountered was proposed.RESULTSThe endoscopic endonasal transpterygoid approach was used to describe the different anatomical structures surrounding the anterior genu of the petrous ICA. Five key anatomical structures were identified and described: the VN, the eustachian tube, the foramen lacerum, the petroclival fissure, and the pharyngobasilar fascia. These structures were specifically quantified and summarized in a schematic acronym-VELPPHA-to describe the area. The VELPPHA area is a dense fibrocartilaginous space around the inferior compartment of the foramen lacerum that can be reached by following the VC posteriorly; this area represents the posterior limits of the transpterygoid approach and, of utmost importance, no neurovascular structures were observed through the VELPPHA area in this study, indicating that it should be a safe zone for surgery in the posterior end of the endoscopic endonasal transpterygoid approach.CONCLUSIONSThe VELPPHA area represents the posterior limits of the endoscopic endonasal transpterygoid approach. Early identification of this area can enhance the safety of the endoscopic endonasal transpterygoid approach expanded to the lateral aspect of the skull base, especially when treating patients with poorly pneumatized sphenoid sinuses.