Surgical management of petrous apex trigeminal nerve herniation causing trigeminal neuralgia with long-term outcome: illustrative case

BACKGROUND: Petrous apex cephaloceles (PACs) are infrequent lesions mostly diagnosed as incidental findings. Rare cases may manifest as trigeminal neuralgia (TN). OBSERVATIONS: A 51-year-old female presented with a 19-year history of TN. Investigative imaging revealed herniation of the trigeminal nerve into Meckel's cave through a right-sided petrous apex defect. The patient underwent a right preauricular middle cranial fossa craniotomy and subtemporal extradural approach to access Meckel's cave. The nerve was released and repositioned, and a fat graft was used to obliterate the petrous apex defect to prevent recurrence. The procedure successfully relieved the patient's severe pain. At the 6-week postoperative follow-up visit, the patient was free from TN symptoms with no surgical complications. At 18 months, the patient was still free from TN symptoms. LESSONS: To the best of the authors' knowledge, there are few reported cases of TN caused by PACs in the literature. This study highlights the importance of considering PACs as a rare but potentially reversible cause of TN, especially in patients with refractory symptoms whose imaging demonstrates no neurovascular conflict. Moreover, the effectiveness of surgical intervention in treating this condition is reinforced. https://thejns.org/doi/10.3171/CASE25460.