The Appropriate Modifier for an Assistant in Surgery

In the event that an operative report indicates an assistant at surgery and the physician documents the purpose of the assistant appropriately, the next consideration is determining what modifier is appropriate for the surgical codes.  There are a number of options to choose from and each has its documentation requirements.

The modifier 80 identifies a surgical assistant.  Assisting surgeons usually charge between 20 to 25 percent of their normal fee for performing the surgery alone.  This reviewer has noted that often the charge is the full surgery fee normally charged by the surgeon.  This occurs most often due to the coding software that produces a fee for the main code and does not take into consideration the modifier.

Modifier 81 is appended when there is a minimum assistant at surgery.  This modifier is used when the surgeon plans to perform the procedure on his own, but due to circumstances in the surgical suite requires the assistance of another surgeon for a short period of time

Modifier 82 indicates that the procedure was performed requiring the presence of an assistant surgeon when a qualified resident surgeon was not available. In teaching hospitals, special requirements must be met to allow billing for an assistant surgeon, and modifier 82 is typically used in those instances. Check with your Medicare carrier for details.

Modifier AS is added to the primary surgical code when the assistant at surgery is a physician assistant, nurse practitioner, or clinical nurse specialist.  This modifier again requires specific documentation.  The operative report should note that no qualified resident was available, the reason for the assistant’s services, and a statement indicating that the primary surgeon has a policy of never involving residents in the preoperative, operative, or postoperative care of his/her patients.

As with medical coding in general, all surgical modifiers must provide documentation as to the reason for the modifier and appending the code to an appropriate root surgical code.