In simple words: The surgeon removes a piece of skull bone to access and remove a pocket of pus (abscess) in the lower back part of the brain. The skull bone is then replaced.

This procedure involves removing a portion of the skull bone (craniectomy) to access and excise a brain abscess located below the tentorium cerebelli (a fold of dura mater separating the cerebellum from the occipital and temporal lobes) or in the posterior fossa (a small space in the brain near the brainstem).After the abscess is removed, any excess fluid or blood is drained. The surgeon then sutures the dural layers, reattaches the bone flap, and closes the scalp incision.

Example 1: A patient presents with a cerebellar abscess confirmed by imaging. Code 61522 is used for the craniectomy and abscess removal in the posterior fossa., A patient develops a brain abscess below the tentorium cerebelli following an infection. Code 61522 is reported for the surgical excision of this infratentorial abscess., An individual with a confirmed posterior fossa abscess undergoes a craniectomy and drainage. Code 61522 would be appropriate as this is within the infratentorial region.

Documentation should include operative notes detailing the location of the abscess (infratentorial or posterior fossa), the size and nature of the abscess, the method of excision, and any complications encountered. Preoperative imaging reports confirming the presence and location of the abscess should also be included.