Neurosurgery Coding Alert

Question: One of our patients had an ALIF of L5-S1. Nine months later, he came back with chronic intractable lower back pain. Our neurosurgeon documented, "Flexion and extension demonstrates a slight instability or micromotion but without gross instability. The decision was made to further stabilize this with percutaneous pedicle screw fixation at L5-S1. Through bilateral incisions to open the fascia, a needle followed by a Kwire was tapped and screws were performed at L5 and S1. Rods were used to connect the screw heads. Incisions were closed." How should we code this, since instrumentation codes are strictly add-on codes and CPT guidelines instruct that these can never be billed as stand-alone codes. Would it be correct to bill this procedure as unlisted?

Answer: Yes, you are correct. You would report the later percutaneous instrumentation the patient received with 64999 (Unlisted procedure, nervous system.) Although revision or removal of previously placed instrumentation is described with standalone codes, the original placement of instrumentation is described with add-on codes, requiring an additional standalone procedure to be performed at the same operative setting to which the instrumentation code is added. You would continue to report 64999 for these procedures, as development of additional stand-alone instrumentation codes has not occurred.