Background: The cavernous sinus (CS) is a highly vulnerable anatomical space, mainly due to the neurovascular structures that it contains; therefore, a detailed knowledge of its anatomy is mandatory for surgical unlocking. In this study, we compared the anatomy of this region from different endoscopic and microsurgical operative corridors, further focusing on the corresponding anatomic landmarks encountered along these routes. Furthermore, we tried to define the safe entry zones to this venous space from these three different operative corridors, and to provide indications regarding the optimal approach according to the lesion’s location. Methods: Five embalmed and injected adult cadaveric specimens (10 sides) separately underwent dissection and exposure of the CS via superior eyelid endoscopic transorbital (SETOA), extended endoscopic endonasal transsphenoidal-transethmoidal (EEEA), and microsurgical transcranial fronto-temporo-orbito-zygomatic (FTOZ) approaches. The anatomical landmarks and the content of this venous space were described and compared from these surgical perspectives. Results: The oculomotor triangle can be clearly exposed only by the FTOZ approach. Unlike EEEA, for the exposure of the clinoid triangle content, the anterior clinoid process removal is required for FTOZ and SETOA. The supra- and infratrochlear as well as the anteromedial and anterolateral triangles can be exposed by all three corridors. The most recently introduced SETOA allowed for the exposure of the entire lateral wall of the CS without entering its neurovascular structures and part of the posterior wall; furthermore, thanks to its anteroposterior trajectory, it allowed for the disclosure of the posterior ascending segment of the cavernous ICA with the related sympathetic plexus through the Mullan’s triangle, in a minimally invasive fashion. Through the anterolateral triangle, the transorbital corridor allowed us to expose the lateral 180 degrees of the Vidian nerve and artery in the homonymous canal, the anterolateral aspect of the lacerum segment of the ICA at the transition zone from the petrous horizontal to the ascending posterior cavernous segment, surrounded by the carotid sympathetic plexus, and the medial Meckel’s cave. Conclusions: Different regions of the cavernous sinus are better exposed by different surgical corridors. The relationship of the tumor with cranial nerves in the lateral wall guides the selection of the approach to cavernous sinus lesions. The transorbital endoscopic approach can be considered to be a safe and minimally invasive complementary surgical corridor to the well-established transcranial and endoscopic endonasal routes for the exposure of selected lesions of the cavernous sinus. Nevertheless, peer knowledge of the anatomy and a surgical learning curve are required.

5-aminolevulinic acid (5-ALA)-induced PpIX fluorescence is used by neurosurgeons to identify the tumor cells of high-grade gliomas during operation. However, the issue of whether 5-ALA-induced PpIX fluorescence consistently stains all the tumor cells is still debated. Here, we assessed the cytoplasmatic signal of 5-ALA by fluorescence microscopy in a series of human gliomas. As tumor markers, we used antibodies against collapsin response-mediated protein 5 (CRMP5), alpha thalassemia/mental retardation syndrome X-linked (ATRX), and anti-isocitrate dehydrogenase 1 (IDH1). In grade III–IV gliomas, the signal induced by 5-ALA was detected in 32.7–75.5 percent of CRMP5-expressing tumor cells. In low-grade gliomas (WHO grade II), the CRMP5-expressing tumor cells did not fluoresce following 5-ALA. Immunofluorescence with antibodies that stain various components of the blood–brain barrier (BBB) suggested that 5-ALA does not cross the un-breached BBB, in spite of its small dimension. To conclude, 5-ALA-induced PpIX fluorescence has an established role in high-grade glioma surgery, but it has limited usefulness in surgery for low-grade glioma, especially when the BBB is preserved.

Personalizing clinical, diagnostic and therapeutic approaches in neuro-oncology is a huge challenge

The prognostic role of epidermal growth factor receptor variant III (EGFRvIII), a constitutively activated oncogenic receptor, in glioblastoma is controversial. We performed a prospective study enrolling 355 patients operated on for de novo glioblastoma at a large academic center. The molecular profile, including EGFRvIII status, MGMT promoter methylation, and VEGF expression, was assessed. Standard parameters (age, clinical status and extent of surgical resection) were confirmed to hold prognostic value. MGMT promoter methylation portended a slightly improved survival. In the whole series, confirming previous results, EGFRvIII was not associated with worsened prognosis. Interestingly, female sex was associated with a better outcome. Such findings are of interest for the design of future trials.

Background: The cavernous sinus (CS) is a highly vulnerable anatomical space, mainly for the neurovascular structures which it contains, therefore a detailed knowledge of its anatomy is mandatory for the surgical unlocking. To compare the anatomy of this region from different endoscopic and microsurgical operative corridors, also focusing on the corresponding anatomic landmarks met along these routes. Furthermore, we tried to define the safe entry zones to this venous space from these three different operative corridors and provide indications regarding the optimal approach according to the lesion location. Methods: Five embalmed and injected adult cadaveric specimens (10 sides) separately underwent dissection and exposure of the CS via superior eyelid endoscopic transorbital (SETOA), extended endoscopic endonasal transsphenoidal-transethmoidal (EEEA) and microsurgical transcranial fronto-temporo-orbito-zygomatic (FTOZ) approaches. The anatomical landmarks and the content of this venous space have been described and compared from these surgical perspectives. Results: The SETOA allowed the exposure of the entire lateral wall of the CS without entering its neurovascular structures and part of the posterior wall; furthermore, thanks to its anteroposterior trajectory, it allowed to disclose in a minimally invasive fashion, also the posterior ascending segment of the cavernous ICA with the related sympathetic plexus through the Mullan’s triangle. Through the anterolateral triangle, the transorbital corridor allowed to expose the lateral 180 degrees of vidian nerve and artery in the homonymous canal, the anterolateral aspect of the lacerum segment of the ICA, at its the transition zone from the petrous horizontal to the ascending posterior cavernous segment, surrounded by the carotid sympathetic plexus, and the medial Meckel’s cave. Conclusion: Different regions of the cavernous sinus are better exposed by different surgical corridors. The relationship of tumor and cranial nerves in the lateral wall guides the selection of the approach to cavernous sinus lesions. The transorbital endoscopic approach can be considered a safe and minimally invasive complementary surgical corridor to the well-established transcranial and endoscopic endonasal routes in the exposure of the cavernous sinus. Nevertheless, peer knowledge of the anatomy and a surgical learning curve are required.

Background and Objectives: The temporoparietal fascia flap (TPFF) has recently emerged as an option for skull base reconstruction in endoscopic transnasal surgery when vascularized nasal flaps are not available. This study provides a systematic literature review of its use in skull base surgery and describes a novel cohort of patients. Methods: PRISMA guidelines were used for the review. Patients undergoing skull base reconstruction with TPFF in our center from May 2022 to April 2024 were retrospectively included. Data were collected on pre- and post-operative clinical and radiological features, histology, surgical procedures, and complications. Results: Sixteen articles were selected, comprising 42 patients who underwent TPFF reconstruction for treatment of complex skull base pathologies. In total, 5 of 358 patients (0.9%) who underwent tumor resection via endoscopic transanal surgery in the study period in our institution required TPFF. All had been previously treated with surgery and radiation therapy for different pathologies (three chordomas, one giant pituitary neuroendocrine tumor (PitNET), and one sarcoma). Post-operative complications included CSF leak, which resolved after flap revision, and an internal carotid artery pseudoaneurysm requiring endovascular embolization. Conclusions: TPFF is an effective option for skull base reconstruction in complex cases and should be part of the armamentarium of the skull base surgeon.