Neurosurgery Coding Alert

Question: The neurosurgeon monitors a patient's nerves while she is in the operating room for surgery. But the diagnosis for the electromyogram (EMG) winds up being different from the intraoperative monitoring (IOM) code. Which diagnosis should I use?

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Answer: If the neurosurgeon performs electrodiagnostic testing such as EMG, evoked potentials or nerve conduction studies (using, for instance, 95860-95864; 95925-95937; 95900, Nerve conduction, amplitude and latency/velocity study, each nerve; motor, without F-wave study; or 95904, ... sensory), you should report the same diagnosis you used to create the medical necessity for the IOM.
 
This is typically the diagnosis you use to establish the need for the surgery. Remember that the operating surgeon cannot concurrently perform and bill for neurophysiological monitoring.
 
Example: The patient undergoes lumbar spinal fusion at multiple levels due to lumbar spinal stenosis. The surgeon and anesthesiologist will probably use 721.42 (Lumbar spondylosis with myelopathy). Therefore, the neurosurgeon performing the baseline electrodiagnostic testing with IOM should also use 721.42 to show medical necessity for the CPT codes he submits (including the baseline study and the IOM, +95920, Intraoperative neurophysiology testing, per hour [list separately in addition to code for primary procedure]).