Assuming that the image guidance is medically necessary and it is documented (more than just a line in "Operations Performed"), the code that is use is +61782, Stereotactic computer-assisted (navigational) procedure; cranial, extradural (List separately in addition to code for primary procedure). Medical necessity is supported by things such as revision surgery, distorted sinus anatomy of development, postoperative, or traumatic origin, extensive sino-nasal polyposis, pathology involving the complex ethmoid, frontal and sphenoid sinuses, disease abutting the skull base, orbit, optic nerve or carotid artery, CSF rhinorrhea or conditions where there is a skull base defect, benign or malignant sino-nasal neoplasms.
61782 is an add on code, so it is modifier exempt and it's fee should not be reduced as a multiple surgery.