Neurosurgery Coding Alert

Question: Which is the proper code to report use of a gamma knife during surgery? Texas Subscriber Answer: The gamma knife employs a single, strong dose of radiation to destroy lesions. Only the tissue being treated receives the radiation, while the surrounding tissue remains unharmed. A lightweight frame is attached to the patient's head. With the frame in place, the patient undergoes an MRI or CT imaging study to locate the diseased area.

The data from the imaging study is used to determine the treatment plan. This portion of the service generally requires one to two hours to complete, and should be billed using +61795 (Stereotactic computer-assisted volumetric [navigational] procedure, intracranial, extracranial, or spinal [list separately in addition to code for primary procedure]). Next, the patient is positioned on the gamma-knife couch and moved into the gamma knife to begin treatment, which can last from 15 minutes to an hour. This portion of the service is reported using 61793 (Stereotactic radiosurgery [particle beam, gamma ray or linear accelerator], one or more sessions). The patient usually remains in observation until the following morning, at which time he or she is discharged.

Note: The radiation oncologist or radiophysicist, if present, will bill for his or her charges independently. Based on national Correct Coding Initiative bundling edits, Medicare will not allow separate billing for placement of the stereotactic frame or the computer-assisted lesion mapping. Some third-party carriers will pay separately for the stereotactic-frame placement using 20660 (Application of cranial tongs, caliper, or stereo-tactic frame, including removal [separate procedure]).