Less invasive retrosigmoid transpetrosal fissure approach for anterior petrous meningioma: A case report with operative video.

Background: Anterior petrous meningiomas pose substantial surgical challenges because of their close association with multiple cranial nerves (CNs) and venous structures. In this case, we demonstrate the retrosigmoid transpetrosal fissure approach for resection of an anterior petrous meningioma. Case Description: A 68-year-old man presented with left-sided facial pain and diplopia due to trigeminal and abducens nerve palsy. Preoperative imaging demonstrated a tumor arising from the anterior petrous surface, with slight extension into the Meckel cave and dorsocaudal displacement of the facial and vestibulocochlear nerves. Detailed preoperative planning using three-dimensional (3D) simulation was performed to evaluate the spatial relationships among the tumor, CN, and superior petrosal vein and to assess the feasibility of splitting the petrosal fissure. A retrosigmoid approach was selected based on the anticipated operative corridor. Careful microsurgical dissection of superior petrosal vein branches provided adequate exposure of the anterior petrous region without excessive manipulation of CN VII and VIII. Continuous intraoperative neurophysiological monitoring was used to facilitate safe tumor resection. Postoperatively, the tumor was removed by a near-total resection, and facial pain and diplopia resolved completely, with preservation of facial and auditory function. Histopathological examination confirmed a World Health Organization grade I meningioma, and no tumor recurrence was observed at the 1-year follow-up. Conclusion: This case report highlights the value of 3D simulation and meticulous microsurgical technique in safely performing the retrosigmoid transpetrosal fissure approach for selected anterior petrous meningiomas.