Reader Question:
Gamma Knife Procedures
Published on Sat Apr 01, 2000
Question: When using the gamma knife for a procedure, what is the correct code or codes that should be used?
Maggie Pruszka
Medical College of Wisconsin, Milwaukee, Wi.
Answer: When neurosurgeons use a gamma knife during a procedure, they should bill with 61793 (stereotactic radiosurgery [particle beam, gamma ray or linear accelerator], one or more sessions) or 61795 (stereotactic computer assisted volumetric [navigational] procedure, intracranial, extracranial, or spinal [list separately in addition to code for primary procedure]).
Gamma radiosurgery allows previously inoperable lesions to be destroyed by doses of finely focused beams of radiation. Determining the duration, direction, and dosage of the beams requires careful analysis of the lesion, dose planning and computer simulation.
The first step is placing a stereotactic frame on the patients head. Local anesthesia is used before the headframe is secured in place with pins that are placed in the forehead and behind the ears. The frame is used in conjunction with an imaging procedure to accurately locate the area within the head to be treated. A CT scan is then done, which allows the neurosurgeon to determine the precise size and location of the lesion in relation to the frame. The tumor coordinates are then input into a computer, and special software is used to determine the proper dosages and other parameters of irradiation. This includes a computerized simulation of the treatment. While the patient rests, a team that includes a neurosurgeon, a radiation oncologist and a medical physicist prepare for the procedure, which generally takes one to two hours to complete, depending on the complexity and location of the problem.
When the proposed individualized dose plan is completed, the patient is positioned on the gamma knife couch. After double checking, the shots are delivered. The total time for delivery of the radiation generally ranges from 15 minutes to several hours. The frame is then removed, and the patient usually goes home the same day.
When billing for the services of the neurosurgeon and not the radiation oncologist or radiophysicist (who have separate charges), the coding is straightforward: Use code 61795 for the intracranial volumetric procedurethat is, determining the size and precise location of the tumor and creating a computer representationand 61793 for the gamma shot itself.
Medicare will not allow separate billing for placement of the stereotactic frame, but many third-party carriers will pay separately for the stereotactic frame placement using code 20660 (application of cranial tongs, caliper, or stereotactic frame, including removal [separate procedure]). A coder should query his or her top five to 10 third-party carriers in writing to learn if 20660 is considered separately reimbursable.
