Endoscopic Endonasal Transclival Approach to Ventral Brainstem Cavernous Malformations: Preliminary Case Series and Technical Note on Clival Reconstruction.

STUDY DESIGN: A retrospective case series of five patients presenting with hemorrhage from ventrally located pontine cavernous malformations, treated between January 2022 and December 2023 with a purely endoscopic endonasal transclival approach. OBJECTIVES: To characterize the perioperative profile of the endoscopic endonasal transclival approach and to assess the adjunctive role of diffusion tensor imaging (DTI) and tractography in surgical planning. In addition, to describe a clival reconstruction technique using polymethyl methacrylate (PMMA) vertebroplasty. METHODS: Five consecutive patients with radiological evidence of hemorrhagic ventral pontine cavernous malformations were retrospectively reviewed. Clinical and radiological features, extent of resection, recurrence, surgical technique, and reconstructive strategy were analyzed. Preoperative MRI was performed in all cases; in elective cases, DTI-based tractography was additionally used for surgical planning, in conjunction with neuronavigation and intraoperative neuromonitoring. Radiological follow-up included immediate postoperative MRI, followed by imaging at 1 month, 3 months, and every 6 months up to 2 years. Endoscopic outpatient evaluations by ENT specialists were performed at 1-2 weeks and at 4 weeks postoperatively. RESULTS: Hemiparesis was the most common presenting symptom in all patients. Gross total resection was achieved in all cases with no intraoperative complications observed. One patient (1/5) required reoperation for postoperative cerebrospinal fluid (CSF) leakage. In one case, a transient worsening of pre-existing neurological deficits (facial nerve palsy, hemiplegia, and strabismus) occurred, with near-complete resolution within 8 weeks. No direct injury to adjacent neurovascular structures was documented. No radiological recurrence was identified during the available follow-up. CONCLUSIONS: In this series, the endoscopic endonasal transclival approach allowed complete lesion resection, as defined by early postoperative imaging, without intraoperative neurovascular injury, with one postoperative CSF leak requiring surgical revision and no observed recurrence at mid-term follow-up. Preoperative DTI tractography provided additional anatomical information that may assist surgical planning and trajectory selection. These findings suggest that this approach is feasible in highly selected patients and support further investigation in larger cohorts.