2026 Poster Presentations
P480: FEASIBILITY, SAFETY, AND OUTCOMES OF THE ENDOSCOPIC ENDONASAL TRANSCLIVAL APPROACH FOR VENTRAL BRAINSTEM CAVERNOUS MALFORMATIONS: A SYSTEMATIC REVIEW
Kivanc Yangi, MD1; Omar Alomari2; Beyzanur Guney2; Aze Bezci3; Omar Y Antar4; Nebal A Alm.Ali3; Bernard R Bendok, MD5; 1Barrow Neurological Institute; 2Hamidiye International School of Medicine, University of Health Sciences, Istanbul, Turkiye; 3Istanbul Medipol University, School of Medicine; 4Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine; 5Department of Neurologic Surgery, Mayo Clinic Arizona
Background & Aim: Brainstem cavernous malformations (BSCMs) are rare vascular lesions with hemorrhagic potential, often associated with considerable morbidity. Although surgery is the primary treatment option, it is challenging due to the proximity of eloquent motor and cranial nerve pathways. While conventional transcranial approaches provide lateral and anterior access, they often involve significant manipulation of neurovascular structures. The endoscopic endonasal transclival approach (EETA) has emerged as a minimally invasive alternative for ventral midline BSCMs (Figure 1). This systematic review aims to evaluate the feasibility, safety, and clinical outcomes of EETA for ventral BSCMs.
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Methods: A systematic search of PubMed, Web of Science, Scopus, and Cochrane databases (inception–July 2025) was performed in accordance with PRISMA guidelines. Eligible studies included patients with BSCMs treated via EETA, reporting on surgical techniques, outcomes, and complications. Data extraction and quality assessment were performed independently by multiple reviewers using NIH and JBI appraisal tools.
Results: A total of 19 clinical (12 case reports, 5 case series, 2 mixed-designs) and 3 cadaveric studies were included, comprising 54 patients who underwent an EETA for ventrally located BSCMs (Figure 2). Patient ages ranged from 14 to 69 years (median: 28 years), with a slight female predominance (58%). The most frequent presenting symptoms were hemiparesis (61%), cranial nerve VI palsy (37%), dysphagia (33%), and headache (31%). Other less frequent symptoms included vertigo (15%), facial numbness (13%), and ataxia (11%). Nearly all patients (94%) presented with radiological evidence of hemorrhage, most often localized to the ventral or ventromedial pons (72%), followed by the medulla (15%) and midbrain (9%). Gross total resection (GTR) was achieved in 70–90% of cases across series, with subtotal resection reported in a minority (n=4). Postoperative improvement in neurological function was observed in the majority, with >65% showing a reduction in preoperative mRS (Modified Rankin Scale) scores during follow-up (mean follow-up: 9 months, range: 3–24 months). The most common complication was CSF leakage, occurring in 5/54 patients (9%), typically within the first postoperative week. Rates were significantly reduced when vascularized nasoseptal flaps were used. New or worsened cranial nerve palsies occurred in 6/54 patients (11%), most commonly involving CN VI and VII; however, the majority were transient and improved within 2–6 months. Infectious complications were rare, with only one case of aseptic meningitis. Other postoperative issues included transient motor deficits (4/54) and dysphagia (2/54). Importantly, no perioperative mortality was reported across the series.
Conclusion: EETA provides direct midline access to ventral BSCMs while minimizing cortical and cranial nerve retraction. Despite challenges such as narrow surgical corridors and CSF leak risk, outcomes suggest favorable neurological recovery when performed with meticulous planning and reconstruction. Larger prospective studies are warranted to validate long-term efficacy and safety.