Neurosurgery Coding Alert

Question: I have an operative report in front of me that is a bit confusing. Notes indicate that the provider performed an outpatient evaluation and management (E/M) service for an established patient. Total encounter time was 43 minutes, and the encounter involved the provider performing moderate medical decision making (MDM). Final diagnosis was ‘trigem. Nerve disorder.’ How should I code this encounter?

Missouri Subscriber

Answer: We’ll tackle the E/M portion first, then drill down for the proper diagnosis code.

E/M: You should report 99215 (Office or other outpatient visit for the evaluation and management of an established patient, which requires a medically appropriate history and/or examination and high level of medical decision making. When using time for code selection, 40-54 minutes of total time is spent on the date of the encounter.) for the E/M service. Based on the 2021 changes to office/ outpatient E/M code descriptors, you can use time or MDM as the sole factor when determining E/M level. Since encounter time puts you in the 99215 bracket, you should opt for this code.

Technically, you wouldn’t be wrong to use 99214 (Office or other outpatient visit for the evaluation and management of an established patient, which requires a medically appropriate history and/or examination and moderate level of medical decision making. When using time for code selection, 30-39 minutes of total time is spent on the date of the encounter.), since the MDM was moderate for the encounter. This coding is not optimal, however, as you could just as rightly report the higher-paying 99215.

ICD-10: Your provider’s final diagnosis, “trigem. Nerve disorder,” does not directly track to a corresponding ICD-10 code. You can get pretty close, however, and then maybe get the provider’s input for a final decision.

The most accurate diagnosis code for this patient resides somewhere in G50.- (Disorders of trigeminal nerve). You have the following codes to choose from in G50:

• G50.0 (Trigeminal neuralgia)
• G50.1 (Atypical facial pain)
• G50.8 (Other disorders of trigeminal nerve)
• G50.9 (Disorder of trigeminal nerve, unspecified)

Best bet: Check the notes to see if there’s anything you overlooked that might give your provider’s diagnosis more clarity. Also, try and query the provider if that is possible. You should use G50.9 if you cannot arrive at a more accurate diagnosis code.