Question: Encounter notes indicate that the patient suffered a herniated brain stem. What is the ICD-10 code for this injury? AAPC Forum Subscriber Answer: Your diagnosis code choice will depend on whether the herniation was traumatic. For non-traumatic brain stem herniation, opt for G93.5 (Compression of brain). Per the synonyms under G93.5, use G93.5 for any of these diagnoses: If, however, the herniation is traumatic, you’ll opt for S06.A1- (Traumatic brain compression with herniation).