Simulated peribulbar injection of anesthetic

To evaluate whether intracranial spreading of a local anesthetic might occur after a peribulbar injection, we did simulated peribulbar anesthetic injections with radiopaque dye into two cadaver heads. Using a standard and modified peribulbar injection with a 25-gauge needle, the four orbits were injected with 8 mL of dye. Computed tomography revealed that the dye spread intraconally and intracranially. In one case the dye was seen tracking along the optic nerve sheath. Since intracranial spreading of a local anesthetic may be associated with adverse sequelae (i.e., brainstem anesthesia), we urge caution and vigilance after both peribulbar and retrobulbar anesthetic injections to prevent cardiopulmonary compromise.