Flavio Nigri

Skull base meningoceles are extremely rare, most commonly resulting from congenital defects in sphenoid bone fusion. Inadequate embryonic fusion between the posterior sphenoid and the occipital bones may result in a transclival meningocele. Given the absence of a formal classification system for clival meningoceles and clear guidelines for the most appropriate endoscopic skull base surgical approach, we combined an anatomical study and a systematic review to characterize anatomical patterns, propose a preliminary classification, and discuss transoral and endonasal surgical corridors according to each clival subtype. In addition, we report the first known case of a primary clival meningocele successfully treated via a transoral endoscopic approach. The study was registered with PROSPERO (CRD42024575282) and received approval from the Ethics Committee (82878724.1.0000.5259). The systematic review followed PRISMA guidelines. PubMed/MEDLINE, Embase, and Cochrane were rigorously searched. Anatomical dissection of midsagittal skull base specimens was performed to assess surgical access to clival regions. Seventeen studies comprising 18 patients (mean age 30.7 years; 72.2% female) were included. Clival defects were classified as posterior transsphenoidal (n = 11), spheno-occipital (n = 1), and basioccipital (n = 6). The endoscopic endonasal approach appeared more appropriate for posterior transsphenoidal cases and the transoral route for basioccipital defects. Anatomical dissection studies confirmed that the endonasal corridor is more suitable for the upper third of the clivus and the transoral route for the lower third.

Background: Subthalamic nucleus-deep brain stimulation (STN-DBS) is a well-established treatment for Parkinson’s disease (PD). Contralateral dyskinesias are often observed during intraoperative testing and are considered predictors of the best postoperative effects on Parkinsonian’s motor disability. Ipsilateral and bilateral dyskinesias are unusual and raise questions about the bilateral functional connectivity within basal nuclei circuitry in PD patients. Case Description: A 47-year-old right-handed male patient with advanced PD presented with freezing of gait, motor fluctuations, and disabling dyskinesias predominantly affecting the left side, despite optimized pharmacological treatment. He was subsequently selected for STN-DBS implantation. During the surgery, the proper, bipolar stimulation of the distal contact (contact 0, cathode; contact 1, anode) at 2 mA induced severe dyskinesia manifesting as chorea, starting in the right lower limb and extending bilaterally. The dyskinesias ceased when stimulation was interrupted. On the left STN, stimulation of the distal contact induced only contralateral lower limb dyskinesias. Conclusion: This case report adds to the discussion on basal nuclei circuitry and its bilateral connections, enhancing our understanding of the physiological mechanisms underlying both the therapeutic and adverse effects of unilateral STN-DBS. It supports the hypothesis of abnormal bilateral connectivity in some PD patients, explaining bilateral dyskinesias and therapeutic implications.

Background: Porencephalic cysts are rare cerebrospinal fluid-filled cavities within the brain parenchyma, classified as either congenital or acquired (secondary to trauma, surgical interventions, ischemia, or infections). Clinical presentations vary depending on the cyst’s size, location, and associated mass effect, with diagnosis established through neuroimaging. This report describes a rare, life-threatening exacerbation of a chronic porencephalic cyst in an adult, progressing to hydrocephalus and acute intracranial hypertension (IH). Case Description: A 57-year-old female presented to an outpatient clinic with an 8-month history of gait disturbances, memory impairment, apathy–abulia, and wheelchair dependence. Eight years earlier, she had sustained a mild traumatic brain injury, during which a porencephalic cyst was incidentally detected on cranial computed tomography (CT) scan; however, she had not been followed up, and the finding was not disclosed during the current evaluation. A new cranial CT and magnetic resonance imaging revealed a large porencephalic cyst in the left frontal lobe with mass effect, bilateral foramen of Monro obstruction, and hydrocephalus. An elective endoscopic cyst-ventricle communication was planned. Two weeks later, the patient presented signs of acute IH, including severe headache, diplopia, and blurred vision. An emergent external ventricular drain (EVD) was placed into the cyst cavity, leading to rapid symptom relief. The EVD was subsequently replaced by a cyst-peritoneal shunt. One year later, the proximal catheter became exposed and required complete shunt removal. Since then, she has remained clinically stable and shunt free. Conclusion: This case represents a rare, adult-onset, life-threatening exacerbation of chronic porencephaly. It demonstrates the importance of long-term follow-up in patients with known porencephalic cysts, even if previously asymptomatic, and the efficacy of timely neurosurgical intervention and close radiological monitoring in preventing severe or potentially fatal complications.

Endolymphatic sac tumor (ELST) is a rare lesion. It may be sporadically or associated with Von Hippel-Lindau syndrome.

Isolated hypertelorism is a rare congenital condition caused by craniofacial malformations.

Temporal bone squamous cell carcinoma (TBSCC) is a very rare condition. The prognosis is dismal for advanced tumors. Due to its rarity, information in the literature is scarce. Here, we report a unique case of TBSCC with cerebellar invasion and hydrocephalus. A 46-year-old reported right-sided hearing loss and a painful right retroauricular mass for 4 months. Magnetic resonance imaging revealed a 8.7 × 7.6 × 6.4 cm mass invading the right temporal and occipital bones. After a biopsy and 3 surgical procedures over 6 months, the diagnosis of TBSCC was obtained. Due to invasion of the cerebellar tissue and obstructive hydrocephalus, a ventriculoperitoneal shunt was performed. The patient was referred for adjuvant radiotherapy. However, palliative care was initiated due to tumor progression. We report a case of advanced TBSCC with poor prognosis despite surgical treatment and radiotherapy. More data are necessary to provide new and better treatment to these patients.

Background: The anatomy and surgical approach to the cavernous sinus and the middle fossa can constitute a considerable challenge, specially for young surgeons. Although their surgical explorations have gone through a popular phase in the past, to this date, they remain an uncomfortable subject for many neurosurgeons. The aim of this paper is to systematically review its anatomy and multiple corridors through a step-by-step dissection of the middle fossa triangles, providing a roadmap for surgeons. Methods: A step-by-step dissection of the cavernous sinus was performed in two fresh-frozen cadavers aiming to describe the anatomy of ten different middle fossa triangles, demonstrating the feasibility of the use of their spaces while surgically approaching this area. Results: The intradural opening of the roof of the cavernous sinus was obtained by dissection of clinoidal, carotid-oculomotor, supratrochlear, optic-carotideal, and oculomotor triangles, allowing an expanded superior view. On the counterpart, the extradural exploration of the lateral wall through the middle fossa floor peeling exposed the infratrochlear, anteromedial, and anterolateral triangles. The middle fossa floor itself was the door to approaching posterior fossa through anterior petrosectomy. The dissection of each individual triangle can be amplified exponentially with exploration of its adjacents, providing broader surgical corridors. Conclusion: The cavernous sinus still remains far from an “every man’s land,” but its systematic study based on direct approaches can ease the challenges of its surgical exploration, allowing surgeons to feel more comfortable with its navigation, with consequently benefit in the treatment of patients.

Background: Cavum septum pellucidum (CSP) and cavum vergae (CV) are normal anatomical variations present in some children, adolescents, and adults. When the cavity is larger than normal, it is called a cyst. Symptomatic cases of CSP and CV cyst are rare, and the clinical presentation is varied. A case with multiple nerve involvement is described. Case Description: A healthy 17-year-old female presented a sudden headache, right cervicobrachialgia, right ptosis, visual changes, and left facial paralysis over 10 days. Head magnetic resonance imaging revealed CSP and CV cyst. Inflammation, infection, and vascular disorders were ruled out. We decided to perform a right transfrontal endoscopic intraventricular septostomy and a right Monro foraminoplasty, which were successful. One month after surgery, the patient had no more signs or symptoms. She has remained asymptomatic for the past year. Conclusion: Multiple nerve involvement was directly related to CSP and CV cyst. The cyst bilaterally occluded the foramen of Monro causing intracranial hypertension. It was possible to obtain complete resolution of the clinical features through neuroendoscopic fenestration and foraminoplasty.

Background: Endoscopic endonasal transsphenoidal approach (EETA) is a well-established technique for sellar tumor resection. However, this route causes aerosol dispersion from the nasal cavity. In the context of the coronavirus (COVID-19) pandemic, new measures were taken aiming at the safety and protection of patients and health-care professionals. Herein, we present a Brazilian experience with EETA during COVID-19 pandemic.Methods: This study was based on the review of medical records and observation in the operating room of the patients undergoing endoscopic surgery in the period from May 2020 to July 2022. All patients were tested by real-time polymerase chain reaction (RT-PCR) COVID-19 before and after surgery. Since September 2021, it has been mandatory to present vaccination cards for adults (over 18 years old).Results: This case series included 28 patients and 35 surgical procedures using the EETA, who presented of nonfunctioning macroadenomas (19 cases − 67.8%), GH-secreting tumor (three cases − 10.8%), ACTH-secreting tumor (three cases − 10.8%), meningiomas (two cases − 7.1%), and Rathke’s cleft cyst (one case – 3.5%). There were eight cases of diabetes insipidus (28.5%), five cases of cerebrospinal fluid leak (17.8%), and one case of meningitis (3.5%). Three patients died due to meningitis (one case), carotid occlusion (one case), and COVID-19 complications (one case).Conclusion: A simple protocol was established to perform EETA during the COVID-19 pandemic. The pituitary surgeries were maintained to treat critical cases. To date, the protocol should be continually updated to improve the procedure’s safety.

Background: Symptomatic isolated costovertebral joint (CVJ) osteoarthritis is rare, and establishing this diagnosis is often difficult. There are few reports in the literature about how to surgically manage these lesions. Our aim was to describe a case of isolated osteoarthritis of the costotransverse joint (CTJ) successfully treated with a resection arthroplasty. Case Description: A 51-year-old female presented with 3 years of the right paravertebral T 10-level back and radiating pain. No conservative treatment modality effectively resolved this pain (i.e., these included anti-inflammatory medications, physiotherapy, and joint blockages). MRI, CT, and technetium-99m methylene diphosphonate bone scintigraphy demonstrated inflammatory changes involving the right T10 CTJ. Following resection arthroplasty, the patient’s symptoms abated. Conclusion: Symptomatic osteoarthritis of the right T10 CVJ successfully resolved following costotransversectomy for joint resection arthroplasty.