Open-door extended endoscopic transorbital technique to the paramedian anterior and middle cranial fossae: technical notes, anatomomorphometric quantitative analysis, and illustrative case.

OBJECTIVE: The superior eyelid endoscopic transorbital approach (SETOA) provides a direct and short minimally invasive route to the anterior and middle skull base. Nevertheless, it uses a narrow corridor that limits its angles of attack. The aim of this study was to evaluate the feasibility and potential benefits of an "extended" conservative variant of the "standard" endoscopic transorbital approach-termed "open-door"-to enhance the exposure of lesions affecting the paramedian aspect of the anterior and middle cranial fossae. METHODS: First, the authors described the technical nuances of the open-door extended transorbital approach (ODETA). Next, they documented its morphometric advantages over standard SETOA. Finally, they provided a clinical-anatomical application to demonstrate enhanced exposure and better angles of attack to treat lesions occupying the paramedian anterior and middle cranial fossae. Five adult cadaveric specimens (10 sides) initially underwent standard SETOA and then extended open-door SETOA (ODETA to the paramedian anterior and middle fossae). The adjunct of hinge-orbitotomy, through three surgical steps and straddling the frontozygomatic suture, converted conventional SETOA to its extended open-door variant. CT scans were performed before dissection and uploaded to the neuronavigation system for quantitative analysis. The angles of attack on the axial plane that addressed four key landmarks, namely the tip of the anterior clinoid process (ACP), foramen rotundum (FR), foramen ovale (FO), and trigeminal impression (TI), were calculated for both operative techniques and compared. RESULTS: Hinge-orbitotomy of the extended open-door SETOA resulted in several surgical, functional, and esthetic advantages: it provided wider axial angles of attack for each of the target points, with a gain angle of 26.68° ± 1.31° for addressing the ACP (p < 0.001), 29.50° ± 2.46° for addressing the FR (p < 0.001), 19.86° ± 1.98° for addressing the FO (p < 0.001), and 17.44° ± 2.21° for addressing the lateral aspect of the TI (p < 0.001), while hiding the skin scar, avoiding temporalis muscle dissection, preserving flap vascularization, and decreasing the rate of bone infection and degree of orbital content retraction. CONCLUSIONS: The extended open-door technique may be specifically suited for selected patients affected by paramedian anterior and middle fossae lesions, with prevalent anteromedial extension toward the anterior clinoid, the foremost compartment of the cavernous sinus and FR and not completely controlled with the pure endoscopic transorbital approach.

The anterolateral triangle as window on the foramen lacerum from transorbital corridor: anatomical study and technical nuances.

OBJECTIVE: Neurosurgical indications for the superior eyelid transorbital endoscopic approach (SETOA) are rapidly expanding over the last years. Nevertheless, as any new technique, a detailed knowledge of the anatomy of the surgical target area, the operative corridor, and the specific surgical landmark from this different perspective is required for a safest and successful surgery. Therefore, the aim of this study is to provide, through anatomical dissections, a detailed investigation of the surgical anatomy revealed by SETOA via anterolateral triangle of the middle cranial fossa. We also sought to define the relevant surgical landmarks of this operative corridor. METHODS: Eight embalmed and injected adult cadaveric specimens (16 sides) underwent dissection and exposure of the cavernous sinus and middle cranial fossa via superior eyelid endoscopic transorbital approach. The anterolateral triangle was opened and its content exposed. An extended endoscopic endonasal trans-clival approach (EEEA) with exposure of the cavernous sinus content and skeletonization of the paraclival and parasellar segments of the internal carotid artery (ICA) was also performed, and the anterolateral triangle was exposed. Measurements of the surface area of this triangle from both surgical corridors were calculated in three head specimens using coordinates of its borders under image-guide navigation. RESULTS: The drilling of the anterolateral triangle via SETOA unfolds a space that can be divided by the course of the vidian nerve into two windows, a wider "supravidian" and a narrower "infravidian," which reveal different anatomical corridors: a "medial supravidian" and a "lateral supravidian," divided by the lacerum segment of the ICA, leading to the lower clivus, and to the medial aspect of the Meckel's cave and terminal part of the horizontal petrous ICA, respectively. The infravidian corridor leads medially into the sphenoid sinus. The arithmetic means of the accessible surface area of the anterolateral triangle were 45.48 ± 3.31 and 42.32 ± 2.17 mm2 through transorbital approach and endonasal approach, respectively. CONCLUSION: SETOA can be considered a minimally invasive route complementary to the extended endoscopic endonasal approach to the anteromedial aspect of the Meckel's cave and the foramen lacerum. The lateral loop of the trigeminal nerve represents a reliable surgical landmark to localize the lacerum segment of the ICA from this corridor. Nevertheless, as any new technique, a learning curve is needed, and the clinical feasibility should be proven.

The feasibility of three port endonasal, transorbital, and sublabial approach to the petroclival region: neurosurgical audit and multiportal anatomic quantitative investigation.

PURPOSE: The petroclival region represents the "Achille's heel" for the neurosurgeons. Many ventral endoscopic routes to this region, mainly performed as isolated, have been described. The aim of the present study is to verify the feasibility of a modular, combined, multiportal approach to the petroclival region to overcome the limits of a single approach, in terms of exposure and working areas, brain retraction and manipulation of neurovascular structures. METHODS: Four cadaver heads (8 sides) underwent endoscopic endonasal transclival, transorbital superior eyelid and contralateral sublabial transmaxillary-Caldwell-Luc approaches, to the petroclival region. CT scans were obtained before and after each approach to rigorously separate the contribution of each osteotomy and subsequentially to build a comprehensive 3D model of the progressively enlarged working area after each step. RESULTS: The addition of the contralateral transmaxillary and transorbital corridors to the extended endoscopic endonasal transclival in a combined multiportal approach provides complementary paramedian trajectories to overcome the natural barrier represented by the parasellar and paraclival segments of the internal carotid artery, resulting in significantly greater area of exposure than a pure endonasal midline route (8,77 cm2 and 11,14 cm2 vs 4,68 cm2 and 5,83cm2, extradural and intradural, respectively). CONCLUSION: The use of different endoscopic "head-on" trajectories can be combined in a wider multiportal extended approach to improve the ventral route to the most inaccessible petroclival regions. Finally, by combining these approaches and reiterating the importance of multiportal strategy, we quantitatively demonstrate the possibility to reach "far away" paramedian petroclival targets while preserving the neurovascular structures.

Functional and clinical outcomes after superior eyelid transorbital endoscopic approach for spheno-orbital meningiomas: illustrative case and literature review.

The pattern of growth of spheno-orbital meningiomas accounts for the main presenting symptoms, such as proptosis, eye motility deficit, visual impairment, diplopia. As these are benign tumors, the postoperative patient's quality of life is an important factor to consider during the preoperative planning. A detailed literature review of superior eyelid transorbital endoscopic approach for spheno-orbital meningiomas, including our own case, was made. A Medline search up to March 2022 in PubMed online electronic database was made using the following key phrases: "superior eyelid endoscopic transorbital approach spheno-orbital meningiomas," "superior eyelid endoscopic transorbital approach," "spheno-orbital meningiomas endoscopic approach." The inclusion criteria were surgical series, reviews, and case reports in English language, as well as papers written in other languages, but including the abstract in English. Cadaveric studies, multiportal combined approaches for SOM, were excluded. The literature review has disclosed five studies for a total of 65 patients, whose demographic, clinical, pathological, surgical, complications, and outcome data were analyzed. Functional and esthetic outcome data after superior eyelid transorbital approach are the following: improvement of proptosis (100%), of visual deficits (66.66%) and of ocular paresis (75%), with only 11 complications (4 trigeminal dysesthesia, 2 CSF leak, 2 wound complications, 1 upper eyelid necrosis, 1 hemorrhage of surgical field, 1 keratitis) reported, but at the expense of extent of resection (gross total resection 33.39%). Based on the outcome data, the superior eyelid transorbital endoscopic approach results in a suitable operative technique for selected spheno-orbital meningiomas.

Review of the main surgical and angiographic-oriented classifications of the course of the internal carotid artery through a novel interactive 3D model.

The course of the internal carotid artery (ICA) and its segment classifications were reviewed by means of a new and freely available 3D interactive model of the artery and the skull base, based on human neuroimages, that can be freely downloaded at the Public Repository of the University of Barcelona (http://diposit.ub.edu/dspace/handle/2445/112442) and runs under Acrobat Reader in Mac and Windows computers and Windows 10 tablets. The 3D-PDF allows zoom, rotation, selective visualization of structures, and a predefined sequence view. Illustrative images of the different classifications were obtained. Fischer (Zentralbl Neurochir 3:300-313, 1938) described five segments in the opposite direction to the blood flow. Gibo-Rothon (J Neurosurg 55:560-574, 1981) follow the blood flow, incorporated the cervical and petrous portions, and divided the subarachnoid course-supraclinoid-in ophthalmic, communicating, and choroidal segments, enhancing transcranial microscopic approaches. Bouthillier (Neurosurgery 38:425-433, 1996) divided the petrous portion describing the lacerum segment (exposed in transfacial procedures and exploration of Meckel's cave) and added the clinoid segment between the proximal and distal dural rings, of interest in cavernous sinus surgery. The Kassam's group (2014), with an endoscopic endonasal perspective, introduces the "paraclival segment," including the "lacerum segment" and part of the intracavernous ICA, and details surgical landmarks to minimize the risk of injury. Other classifications are also analyzed. This review through an interactive 3D tool provides virtual views of the ICA and becomes an innovative perspective to the segment classifications and neuroanatomy of the ICA and surrounding structures.

Fluorescein-assisted stereotactic needle biopsy of brain tumors: a single-center experience and systematic review.

Over the last years, fluorescence-based technology has begun an emergent intraoperative method for diagnostic confirmation of brain tumor tissue in stereotactic needle biopsy. However, the actual level of evidence is quite low, especially about fluorescein sodium (FL) application. This method needs to be further validated and better analyzed about its impact in clinical practice. Retrospective analysis of 11 cases with contrast-enhancing brain tumors, underwent awake stereotactic needle biopsy with intraoperative FL assistance (group 1), was verified under the operative microscope filter. This group was matched with a control group of 18 patients (group 2). In addition, a systematic literature review was performed in PubMed/Medline database according to PRISMA statement. All studies concerning FL or 5-ALA application in stereotactic biopsy as intraoperative confirmation of brain tumor tissue were included. The primary endpoint was the evaluation of diagnostic accuracy. In group 1, all fluorescent specimens were diagnostic. The number of samplings was the useful minimum and non-use of intraoperative neuropathological examination allowed to significantly reduce procedure time (42.09 vs 69.72 min of group 2). No complications occurred, and the average hospitalization time after procedure was 1.09 days (vs 2.33 of group 2). Literature analysis supports the usefulness of photodiagnosis and its high diagnostic yield especially at the core of high-grade/contrast-enhancing tumors. FL assistance during stereotactic biopsy of contrast-enhancing brain tumors may give a real-time confirmation of tumor tissue, maximizing the diagnostic yield, and reducing time of procedure, morbidity, and hospitalization.

Multimodal use of indocyanine green endoscopy in neurosurgery: a single-center experience and review of the literature.

During the last 10 years, microscope-integrated indocyanine green fluorescence (m-ICG) has been widely used for assessing real-time blood flow during aneurysm surgery. More recently, an endoscope-integrated indocyanine green fluorescence (e-ICG) has been adopted as a versatile tool during different endoscopic neurosurgical procedures. The purpose of the present report is to evaluate multimodal applications of e-ICG during different endonasal, intraventricular, aneurysm and brain tumor surgeries and provide technical nuances. In addition, we reviewed the literature and identified and compare several overlapping case series of patients treated via an endoscopic integrated indocyanine green fluorescence technique. A total of 40 patients were retrospectively evaluated. Patients were divided into four main groups: (1) endoscopic endonasal approaches (n = 14); (2) ventricular endoscopic approach including patients undergoing third ventriculostomy (n = 8) and tumor biopsy (n = 1); (3) aneurysms surgery (n = 9); and (4) brain parenchymal tumors (n = 8). All patients were successfully treated using the e-ICG dynamic endoscopic visualization, and there were no perioperative complications. Such unique features open up a promising field of applications beyond the use of m-ICG in different surgical field due to the longer duration of e-ICG fluorescence up to 35 ± 7 min. E-ICG represents a new and effective technique for longer real-time visualization of vascular structures preserving normal tissues and functions during different transcranial and endonasal approaches. As the technology and e-ICG resolution improves, the technique has the potential to become a critical tool for different applications in neurosurgery.

A Novel and Freely Available Interactive 3d Model of the Internal Carotid Artery.

We describe a new and freely available 3D interactive model of the intracranial internal carotid artery (ICA) and the skull base that also allows to display and compare its main segment classifications. High-resolution 3D human angiography (isometric voxel's size 0.36 mm) and Computed Tomography angiography images were exported to Virtual Reality Modeling Language (VRML) format for processing in a 3D software platform and embedding in a 3D Portable Document Format (PDF) document that can be freely downloaded at http://diposit.ub.edu/dspace/handle/2445/112442 and runs under Acrobat Reader on Mac and Windows computers and Windows 10 tablets. The 3D-PDF allows for visualisation and interaction through JavaScript-based functions (including zoom, rotation, selective visualization and transparentation of structures or a predefined sequence view of the main segment classifications if desired). The ICA and its main branches and loops, the Gasserian ganglion, the petrolingual ligament and the proximal and distal dural rings within the skull base environment (anterior and posterior clinoid processes, silla turcica, ethmoid and sphenoid bones, orbital fossae) may be visualized from different perspectives. This interactive 3D-PDF provides virtual views of the ICA and becomes an innovative tool to improve the understanding of the neuroanatomy of the ICA and surrounding structures.

The use of a three-dimensional endoscope for different skull base tumors: results of a preliminary extended endonasal surgical series.

BACKGROUND: The evolution of skull base surgery over the past decade has been influenced by advancement in visualization technology. Recently, as a result of such improvements, three-dimensional (3-D) scopes have been widely used during endoscopic endonasal approaches. In the present study, we describe the use of 3-D stereoscopic endoscope for the treatment of a variety of skull base lesions. METHODS: From January 2010 to June 2015, a 3-D endoscopic endonasal approach (4 and 4.9 mm, 0°, and 30° rigid endoscopes) was performed in 70 patients with the following lesions: 42 large extrasellar pituitary macroadenomas, seven tuberculum sellae meningiomas, seven clivus chordomas, five craniopharyngiomas, three fibrous dysplasia of the clivus, three sinonasal malignancies, one orbital lymphangioma, one trigeminal neurinoma, one primary suprasellar lymphoma. RESULTS: Total tumor removal was obtained in 50 patients (71.4 %) while in 14 (20 %), subtotal removal was possible in six (8.6 %) only partial removal was achieved. Overall complications included diabetes insipidus in eight patients (11.4 %), hypopituitarism in seven patients (10 %), CSF leak in five patients (7.1 %), cranial nerve injury in two patients (2.8 %), panhypopituitarism in two patients (2.8 %), meningitis in one (1.4 %) and one postoperative central retinal artery occlusion (1.4 %). There was no mortality in the series. The mean follow-up time was 39 months (range, 6-72 months). CONCLUSIONS: In our experience, the 3-D endoscope represents a critical development in visualization, thus enabling improved hand-eye coordination and depth perception, which are mandatory for the management of complex intradural neurovascular structures during tumor removal surgery.

Long-term outcomes of endoscopic endonasal approach for skull base surgery: a prospective study.

UNLABELLED: Little is known about the long-term effects of either transnasal transsphenoidal endoscopic approach (TTEA) or expanded endonasal approach (EEA). This study assessed the long-term impact of endoscopic skull base surgery on olfaction, sinonasal symptoms, mucociliary clearance time (MCT), and quality of life (QoL). Patients with pituitary adenomas underwent TTEA (n = 38), while patients with other benign parasellar tumours who underwent an EEA with vascularised septal flap reconstruction (n = 17) were enrolled in this prospective study between 2009 and 2012. Sinonasal symptoms (Visual Analogue Scale), subjective olfactometry (Barcelona Smell Test-24, BAST-24), MCT (saccharin test), and QoL (short form SF-36, rhinosinusitis outcome measure/RSOM) were evaluated before, and 12 months after, surgery. At baseline, sinonasal symptoms, MCT, BAST-24, and QoL were similar between groups. Twelve months after surgery, both TTEA and EEA groups experienced smell impairment compared to baseline. Moreover, EEA (but not TTEA) patients reported increased posterior nasal discharge and longer MCTs compared to baseline. No significant changes in olfactometry or QoL were detected in either group 12 months after surgery. Over the long-term, expanded skull base surgery, using EEA, produced more sinonasal symptoms (including loss of smell) and longer MCTs than pituitary surgery (TTEA). EEA showed no long-term impact on smell test or QoL. LEVEL OF EVIDENCE: IIb.

The extended endoscopic endonasal transplanum transtuberculum approach to the anterior communicating artery complex: anatomic study.

BACKGROUND: When performing a transplanum transtuberculum approach, dealing with the anterior communicating artery (ACoA) complex is inevitable. The aim of this study is to provide quantitative anatomical information regarding the ACoA complex and its bony and neural relationships, when exposed through this approach. METHOD: The endoscopic endonasal transplanum transtuberculum approach was performed on ten human cadaver heads. In each specimen, radiological studies were performed. A three-dimensional model of the approach was reconstructed. Measured parameters were: exposure of the vessels; distance between the proximal anterior cerebral artery (A1) and the optic chiasm; dimension of the bone opening. The feasibility to perform clip placement was graded as "possible" or "not possible". RESULTS: Dimension of bone opening varied from 88 to 53 mm(2). The ACoA was exposed for 3 mm ± 2 mm, A1 for 17 mm ± 9 mm, the distal anterior cerebral artery (A2) for 12 mm ± 3 mm, the recurrent artery of Heubner (RAH) for 16 mm ± 4 mm. Clip placement was possible on the ACoA, A2, and distal segment of A1 in all cases, and on the proximal segment of A1 in one instance. The distance between A1 and the optic chiasm measured 9 mm ± 2 mm. CONCLUSIONS: The ACoA, A2, and the distal segment of A1 can be visualized and controlled through the transplanum transtuberculum approach. The relationship between A1, gyrus rectus, and optic chiasm is the main determinant for the exposure and control of the vessel. The olfactory nerve can represent a surgical landmark for the identification of the A1 origin. The whole course of the RAH can be visualized trough this approach.

Pedicled lateral nasal wall flap for the reconstruction of the nasal septum perforation. A radio-anatomical study.

INTRODUCTION: The aim of this radio-anatomical study is to ensure that the potential donor area of the pedicled lateral nasal wall flap (PLNW) is adequate to reconstruct nasal perforation. MATERIAL AND METHODS: Analysis was conducted on 40 de-identified CT angiographies. The area and length of the PLNW, the septum, and the nasal floor were measured. In a cadaver study, 20 hemi-cranial sagittal sections were also analyzed. The anterior-posterior length of the PLNW flap and the distance between the sphenopalatine foramen and piriform aperture were measured. A clinical study with endoscopic closure of a large perforation was conducted in three patients. RESULTS: The CT angiographies demonstrated an average PLNW area of 10.80±1.13 cm2 and a nasal floor area of 3.78±0.58 cm2. The septal area (22.54±21.32 cm2) was significantly larger than the total PLNW flap area (14.59±1.21 cm2). The average length of the flap was 5.58±0.39 cm, while the septum was 6.66±0.42 cm; therefore the PLNW flap is insufficient to reconstruct the entire septum. The cadaver study showed that the length of the PLNW flap was 5.28±0.40 cm. These results demonstrate that measurements obtained from CT scans are reliable data and similar to those found in the radiological study. Complete closure was achieved in all three patients. CONCLUSION: The PLNW flap does not render enough tissue to reconstruct a total septal perforation; however, up to 84% of the septum could be repaired with a PLNW. The potential donor area obtained by CT scan and clinical practice support the approachability of PLNW to repair large septal perforation.

Interactive 3D-PDF Presentations for the Simulation and Quantification of Extended Endoscopic Endonasal Surgical Approaches.

A three-dimensional (3D) model of the skull base was reconstructed from the pre- and post-dissection head CT images and embedded in a Portable Document Format (PDF) file, which can be opened by freely available software and used offline. The CT images were segmented using a specific 3D software platform for biomedical data, and the resulting 3D geometrical models of anatomical structures were used for dual purpose: to simulate the extended endoscopic endonasal transsphenoidal approaches and to perform the quantitative analysis of the procedures. The analysis consisted of bone removal quantification and the calculation of quantitative parameters (surgical freedom and exposure area) of each procedure. The results are presented in three PDF documents containing JavaScript-based functions. The 3D-PDF files include reconstructions of the nasal structures (nasal septum, vomer, middle turbinates), the bony structures of the anterior skull base and maxillofacial region and partial reconstructions of the optic nerve, the hypoglossal and vidian canals and the internal carotid arteries. Alongside the anatomical model, axial, sagittal and coronal CT images are shown. Interactive 3D presentations were created to explain the surgery and the associated quantification methods step-by-step. The resulting 3D-PDF files allow the user to interact with the model through easily available software, free of charge and in an intuitive manner. The files are available for offline use on a personal computer and no previous specialized knowledge in informatics is required. The documents can be downloaded at http://hdl.handle.net/2445/55224 .

Extended endoscopic endonasal transclival approach to the ventrolateral brainstem and related cisternal spaces: anatomical study.

Advances in endoscopic endonasal skull base surgery have led to the development of new routes to areas beyond the midline skull base. Recently, feasible surgical corridors to the lateral skull base have been described. The aim of this study was to describe the anatomical exposure of the ventrolateral brainstem and posterior fossa through an extended endoscopic endonasal transclival transpetrosal and transcondylar approach. Six human heads were used for the dissection process. The arterial and venous systems were injected with red- and blue-colored latex, respectively. A pre- and postoperative computed tomography (CT) scan was carried out on every head. The endoscopic endonasal transclival approach was extended through an anterior petrosectomy and a medial condylectomy. A three-dimensional model of the approach was reconstructed, using a dedicated software, from the overlapping of the pre- and post-dissection CT imaging of the specimen. An extended endoscopic transclival approach allows to gain access through an extradural anterior petrosectomy and medial condylectomy to the anterolateral surface of the brainstem and the posterior fossa. Two main intradural anatomical corridors can be described: first, between the V cranial nerve in the prepontine cistern and the VII-VIII cranial nerves in the cerebellopontine and cerebellomedullary cistern; second, between the VII-VIII cranial nerves and the IX cranial nerve, in the premedullary cistern. Extending the transclival endoscopic approach by performing an extradural anterior petrosectomy and a medial condylectomy provides a safe and wide exposure of the anterolateral brainstem with feasible surgical corridors around the main neurovascular structures.

Quantitative study on endoscopic endonasal approach to the posterior sino-orbito-cranial interface: implications and clinical considerations.

The posterior sino-orbito-cranial interface is a critical area in the skull base since it represents a gateway to deeper vital regions. Quantification of the surgical freedom for any given point/area is an objective method for comparing in a reproducible way different surgical approaches. Three freshly injected cadaver heads (six sides) were dissected under the magnetic navigation control system. The surgical freedom (SF) and the angle of attack of fixed target points were determined from the ipsilateral nasal fossa, from the contralateral nasal fossa (after posterior septectomy), and after an anteromedial maxillotomy (according to the Denker procedure). The mean pre-operative SF value resulted to be 403.07 ± 102.73 mm(2) for the ipsilateral nostril, increasing by 126.97 % for the binostril approach, by 118.45 % for the monolateral nostril approach after anteromedial maxillotomy, and by 310.48 % for the binostril approach after bilateral anteromedial maxillotomy. Laterally extended lesions require an anteromedial maxillotomy, while more medially located lesions can be managed by means of a posterior septectomy. When addressing the posterior sino-orbito-cranial interface, the transnasal binostril approach and anteromedial maxillotomy both increase the SF. The choice between them depends on exact position, relationship and clinical behaviour of the lesion to treat.

Case Report of Indocyanine Green Endoscopy for Intrasellar Pituitary Adenoma Resection.

Indocyanine green (ICG) angiography has become an established technology in many surgical fields, as well as in neurosurgery with the first application of microscope-integrated indocyanine angiography, which dates to 2003.1 More recently we observed the integration of ICG into endoscopic visualization (e-ICG), which resulted in different applications during the endoscopic endonasal approach ranging from evaluation of intranasal flap perfusion to differentiation of pituitary neuroendocrine tumors from normal gland or even as a predictive factor of postoperative visual function after expanded approaches.2-8 A 49-year-old woman was admitted to our hospital after a 1-year history of amenorrhea and radiologic finding of an intrasellar lesion. The clinical picture was compatible with a nonfunctioning pituitary neuroendocrine tumor, and the mass was completely removed by means of an endoscopic endonasal approach with intraoperative use of e-ICG (Video 1). A 25 mg intravenous bolus of ICG was injected immediately after completion of the sphenoid phase of the approach. ICG was visualized with a dedicated ICG-integrated endoscope coupled to an IMAGE1 S camera system set on Chroma enhancement mode. Near-infrared excitation of fluorescence (780-820 nm) was obtained using a D-light P Cold Light Fountain. At follow-up, the patient experienced resolution of her symptoms, without residues or relapses on control magnetic resonance. This case sheds light on some possible applications and advantages of e-ICG, including visualization of internal carotid arteries before the sellar opening, individuation of the pituitary gland, its distinction from the adenomatous tissue, and the possible evaluation of its degree of compression.

Combined Endoscopic Endonasal Transclival and Contralateral Transmaxillary Approach to the Petrous Apex and the Petroclival Synchondrosis: Working "Around the Corner" of the Internal Carotid Artery-Quantitative Anatomical Study and Clinical Applications.

The endoscopic contralateral transmaxillary (CTM) approach has been proposed as a potential route to widen the corridor posterolateral to the internal carotid artery (ICA). In this study, we first refined the surgical technique of a combined multiportal endoscopic endonasal transclival (EETC) and CTM approach to the petrous apex (PA) and petroclival synchondrosis (PCS) in the dissection laboratory, and then validated its applications in a preliminary surgical series. The combined EETC and CTM approach was performed on three cadaver specimens based on four surgical steps: (1) the nasal, (2) the clival, (3) the maxillary and (4) the petrosal phases. The CTM provided a "head-on trajectory" to the PA and PCS and a short distance to the surgical field considerably furthering surgical maneuverability. The best operative set-up was achieved by introducing angled optics via the endonasal route and operative instruments via the transmaxillary corridor exploiting the advantages of a non-coaxial multiportal surgery. Clinical applications of the combined EETC and CTM approach were reported in three cases, a clival chordoma and two giant pituitary adenomas. The present translational study explores the safety and feasibility of a combined multiportal EETC and CTM approach to access the petroclival region though different corridors.

The Course of the Trochlear Nerve Presented via a 3-Dimensional Photorealistic Anatomic Model.

OBJECTIVES: Several factors contribute to the anatomical complexity of the trochlear nerve, including small diameter, complex and longest intracranial course, deep location, and numerous neurovascular relationships. A 3-dimensional (3D) photorealistic model of the cranial nerves provides a detailed and immersive representation of the anatomy, enabling one to improve surgical planning, advanced surgical research, and training. The purpose of this work is to present a 3D photogrammetric study for a more intuitive and interactive way to explore and describe the entire course of trochlear nerve. METHODS: Two injected-fixed head human specimens (4 sides) were examined. The dissection protocol was divided into the following steps: 1) brain hemisphere exposure; 2) hemispherectomy dissecting all cranial nerves and partial removal of the free edge of the tentorium; 3) middle fossa and lateral wall of cavernous sinus exposure; and 4) orbital exposure. A detailed 3D photogrammetric model was generated for each dissection step. RESULTS: Four main volumetric models were generated during a step-by-step layered dissection of the entire nerve pathway highlighting its different segments. Finally, a full and integrated model of the entire course of the nerve was created. The models are available for visualization on monoscopic display, virtual, and augmented reality environment. CONCLUSIONS: The present photogrammetric model provides a more comprehensive understanding of the nerve's anatomy in its different segments, allows for customizable views thus simulating different perspectives, and can be a valuable alternative to traditional dissections. It is an advanced tool for surgical planning and surgical simulation as well as virtual reality representation of the anatomy.

Endoscopic Transorbital Resection of Temporal Pole Cavernoma: 2-Dimensional Operative Video.

An endoscopic transorbital approach has been recently included in the neurosurgical armamentarium.1 We present a case of a 31-year-old female patient with a history of recent-onset refractory epilepsy related to a left temporal pole cavernoma operated through a superior eyelid endoscopic transorbital approach. The operative video shows the key surgical steps to ensure optimal surgical freedom, adequate exposure, and complete tumor resection.2 The postoperative course was uneventful, and the patient obtained seizure control and good cosmetic results without postoperative complications. The brain computed tomography and MRI showed the size of bone removal and confirmed the complete removal of the lesion, respectively. At 3-month follow-up, the patient is epileptic seizures-free without medications. An endoscopic transorbital approach provides adequate exposure of the temporal pole, allowing safe tumor resection. Complication avoidance encompasses careful dissection of palpebral muscles, dynamic orbital retraction, and neuronavigation guidance; sphenoidal drilling according to key anatomic landmarks (eg, sagittal crest3); and anatomic knowledge of the cavernous sinus and internal carotid artery and its tributaries course from a transorbital perspective4 and reconstruction filling the empty spaces using fat, fascia lata, or dural substitutes. All procedures performed were approved by the ethics committee of both centers and in accordance with Declaration of Helsinki and its later amendments. The patient consented to the procedure and to the publication of her images, and appropriate consent was obtained for publication of cadaveric images.

Navigating the Intersection Between the Orbit and the Skull Base: The "Mirror" McCarty Keyhole During Transorbital Approach: An Anatomic Study With Surgical Implications.

BACKGROUND AND OBJECTIVES: McCarty keyhole (MCK) is the most important entry point during orbitocranial and cranio-orbital approaches; nevertheless, its anatomic coordinates have never been detailedly described from transorbital perspective. To provide the spatial coordinates for intraorbital projection of the "mirror" MCK by using the well-established main anatomic-surgical bony landmarks met along transorbital corridor. METHODS: MCK was identified in 15 adult dry skulls (30 sides) on exocranial surface of pterional region based on the well-defined external bony landmarks: on the frontosphenoid suture, 5 to 6 mm behind the joining point (JP) of frontozygomatic suture (FZS), frontosphenoid suture (FSS), and sphenozygomatic suture (SZS). A 1-mm burr hole was performed and progressively enlarged to identify the intracranial and intraorbital compartments. Exit site of the intraorbital part of burr hole was referenced to the FZS on the orbital rim, the superior orbital fissure, and the inferior orbital fissure and to the JP of FZS, FSS, and SZS. To electronically validate the results, 3-dimensional photorealistic and interactive models were reconstructed with photogrammetry. Finally, for a further validation, McCarty mirror keyhole was also exposed, based on results achieved, through endoscopic transorbital approach in 10 head specimens (20 sides). RESULTS: Intraorbital projection of MCK was identified on the FSS on intraorbital surface, 1.5 ± 0.5 mm posterior to JP, 11.5 ± 1.1 mm posterior to the FZS on orbital rim following the suture, 13.0 ± 1.2 mm from most anterior end of superior orbital fissure, 15.5 ± 1.4 mm from the most anterior end of the inferior orbital fissure in vertical line, on measurements under direct macroscopic visualization (mean ± SD). These values were electronically confirmed on the photogrammetric models with mean difference within 1 mm. CONCLUSION: To be aware of exact position of intraorbital projection of MCK during an early stage of transorbital approaches provides several surgical, clinical, and aesthetic advantages.