Question: How should I code aspiration of spinal fluid from an implanted pump (the patient was under anesthesia)? I cannot find a surgical code to accurately describe irrigation, declotting, etc., of a morphine pump. Kansas Subscriber Answer: The most likely code for the procedure from a surgical standpoint is 64999 (Unlisted procedure, nervous system). The most applicable anesthesia code is 00300 (Anesthesia for all procedures on the integumentary system, muscles and nerves of head, neck, and posterior trunk, not otherwise specified) or 00400 (Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; not otherwise specified), depending on the pump's location and whether you are dealing with the anterior or posterior side. Surgical code 64999 crosses to anesthesia code 01999 (Unlisted anesthesia procedure[s]), but more accurate coding always entails using a site-specific code rather than an unlisted procedure code, if possible.