Anatomy for Microsurgery of Paragangliomas

Jugular foramen pathologies are complex and demand extensive anatomical knowledge to tailor the best approach. The most common tumor at this location is paraganglioma, followed by lower cranial nerves, schwannomas and meningiomas. Presenting symptoms include hearing loss and tinnitus due to the involvement of middle ear structures; also, the impairment of lower cranial nerves or facial nerve function is common. Paragangliomas are complex tumors, involved with different clinical syndromes, possibility of multifocal lesions and endocrine function, and demand a careful preoperative workup. Most tumors have microsurgical resection as the primary treatment option, and a combination of age, performance status, neurological deficits, and tumor features must be balanced to indicate a more aggressive or conservative intervention. Usually, radiosurgery is reserved for residual tumors or patients unsuitable for microsurgical excision. Depending on tumor extensions and if primarily originated at the jugular foramen, or involved this area as a secondary extension, different surgical approaches may be chosen; however, we usually prefer variations of the infratemporal fossa approach to resect jugular foramen tumors. A key point is that the anteromedial wall of the internal jugular vein should be preserved if there is preoperative function preservation of lower cranial nerves. Also, the mastoid segment of facial nerve is exposed just if there is preoperative facial palsy, to decompress or graft the nerve. Depending on tumor extensions and blood supply, variations of infratemporal fossa approach may be adopted. Laboratory training is essential to improve anatomical knowledge of complex surgical approaches towards jugular foramen.