The Quadrangular Space, Endonasal Access to the Meckel Cave: Technical Considerations and Clinical Series.

OBJECTIVE: An anteromedial corridor via an expanded endoscopic endonasal approach to the Meckel cave (MC) was described more than a decade ago. However, few clinical series or endoscopic endonasal technical contributions exist concerning this type of approach to this complex region. METHODS: We present a detailed description of the surgical technique for this approach reviewing the original technique and adding clarifying conceptual notions. We conducted a multicenter retrospective study selecting patients who underwent endonasal endoscopic surgery for lesions exclusively limited to the MC in the past 6 years. Intraoperative and postoperative complications were analyzed. The study of 10 cadaveric specimens provides additional information. RESULTS: We performed a fully endoscopic anteromedial corridor to the MC in 18 patients. The most prevalent pathologic finding was schwannoma of the V nerve in 4 patients. Sixth cranial nerve palsy (13 patients) and trigeminal dysfunction (10 patients) were the predominant preoperative clinical signs. There were no remarkable intraoperative complications. Corneal keratopathy caused by dry eye syndrome affected 3 patients and V2 residual neuralgia appeared postoperatively in 2 patients. Six patients recovered from sixth cranial nerve palsy, and 2 showed improvement in preoperatively referred facial pain. CONCLUSIONS: The front door to the MC via the endonasal anteromedial corridor could be a good option. Understanding of the anatomy and the concept of the quadrangular space is crucial to performing this technique safely, which has few complications in experienced hands. Recovery from sixth nerve palsy is possible with this approach. Corneal keratopathy in these patients is a potential complication.

Endonasal Odontoidectomy in Basilar Invagination.

Objective The endoscopic endonasal odontoidectomy (EEO) is emerging as a feasible surgical alternative to conventional microscopic transoral approach. In this article, we show EEO in the basilar invagination (BI) and describe in detail the technical aspects, advantages, and disadvantages of this approach ( Fig. 1 ). Methods We describe EEO using audiovisual material from the neurosurgical department of Hospital Universitari i Politècnic La Fe Valencia database. Results We present the case of a 61-year-old male patient with BI. Initially, we performed suboccipital decompression and occipitocervical fusion. Subsequently, after a no significant neurological improvement and persistent anterior compression, EEO was performed. The postoperative evolution was uneventful and the preoperative neurological deficits were recovered rapidly after surgery Discussion EEO technique enables complete odontoid resection, preventing invasion of aggressive oral bacterial flora, and it is not limited by the mouth opening. As well, it avoids manipulation of the soft palate, therefore evades the risk of velopalatal insufficiency, facilitates immediate oral tolerance, and early extubation. The rostral position of C1-C2 complex in BI could suppose a great advantage in favor the endonasal approaches. Mucoperichondrial vascularized flaps could be obtained to avoid a postoperative cerebrospinal fluid (CSF) leak and facilitate the reepithelization process of the surgical bed. Conclusion EEO may provide a significant anatomic and technical advantage over the trans-oral approach. The link to the video can be found at: https://youtu.be/Td6MDcjCNKk .

Spontaneous CSF rhinorrhea as a presenting symptom of a clival chordoma.

CSF rhinorrhea is a rare presenting symptom of a clival chordoma as these tumors do not tend to show dural invasion as a histological feature. Here we discuss the case of a 61 years old female with spontaneous rhinorrhea secondary to a clival chordoma, and the value of some specific MRI sequences in accurate identification of a tumor with such atypical presentation, enabling the surgeon to plan accordingly.

Gangliogliomas in the pediatric population.

BACKGROUND: Gangliogliomas are neoplastic lesions composed by a mixed population of neoplastic glial and dysplastic neural cells. They represent around 5% of all CNS tumors in the pediatric population. These usually are well-differentiated, slow-growing tumors, meaning that complete resection could cure most of these patients. Although most lesions remain stable over time after incomplete resection, some patients develop progression of the residual lesions: the optimal approach to treat these tumors is still to be defined. METHODS: This is a retrospective study in which we obtained data from medical records of pediatric patients who had a histological diagnosis of ganglioglioma following surgical treatment at a single center between 2001 and 2020. RESULTS: We included 17 pediatric subjects with gangliogliomas. The median age at diagnosis was 6.7 years, and the median follow-up duration was 60 months. The most common clinical presentation was epileptic seizures (41.1%). Hydrocephalus was present in 29.4% of cases. 52.9% of tumors involved exclusively the cerebral hemispheres, with the temporal lobe being the most affected location. Gross total tumor resection (GTR) was accomplished in 47% of all cases and in 75% of hemispheric tumors. Of patients, 33% in whom GTR could not be achieved showed progression of the residual tumor. BRAF V600E mutation was present in 44.4% of cases. CONCLUSION: Gangliogliomas are typically grade I tumors that occasionally affect children. They classically localize in the cerebral hemisphere but may involve deep structures like the basal ganglia, brain stem, and cerebellum, which seems to be particularly frequent in the pediatric population, implying further challenge to achieve adequate oncological control with surgery as the only treatment modality. Although most cases in which GTR could not be performed remained stable over the follow-up, significant progression of the tumor remains was observed in some patients. BRAF inhibitors should be considered as a feasible treatment option in this setting.

Indocyanine green videoangiography methodological variations: review.

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies. We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature. A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect florescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed. More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.