Intraoperative Monitoring for Surgeries at the Jugular Foramen

Abstract

Tumors associated with the jugular foramen (JF) place cranial nerves (CNs), IX, X, and XI at risk of damage. Depending on the size and location of the tumor, CNs V, VI, VII, VIII, and XII also may be compromised during surgery. Intraoperative monitoring methodology must fulfill three criteria: (1) continuous monitoring of the functional integrity of the neural elements at risk to detect imminent injury or moment of injury; (2) transfer of real-time information to the surgeon quickly enough to prevent permanent injury to the nervous system; and (3) use of direct electrical stimulation of exposed nerve tissue to identify (map) these structures neurophysiologically to avoid their injury during surgery. Protection of the CNs is the primary goal of monitoring when applying protocols for JF procedures to minimize neurologic deficits. Monitoring these CNs does not prevent all injuries but can reduce the probability of nerve injury by helping to map the nerve trajectories and by warning the surgeon that the present surgical manipulation is affecting a specific nerve, whether the surgeon sees the nerve or it is hidden in the surgical field.