Below is from 2001 Oct CPT Assistant
The following article builds on information originally presented in the February 1997 CPT Assistant article, "Anesthesia: Coding for Procedural Services."
Codes for procedures commonly used in the management of postoperative pain include 62318 and 62319 (both introduced in CPT 2000) for continuous epidural analgesia and the series of codes for somatic nerve blocks (64400-64450).
It is appropriate to report pain management procedures, including the insertion of an epidural catheter or the performance of a nerve block, for postoperative analgesia separately from the administration of a general anesthetic.
When general anesthesia is administered and these injections are performed to provide postoperative analgesia, they are separate and distinct services and are reported in addition to the anesthesia code. Whether the block procedure (insertion of catheter; injection of narcotic or local anesthetic agent) occurs preoperatively, postoperatively, or during the procedure is immaterial.
If, on the other hand, the block procedure is used primarily for the anesthesia itself, the service should be reported using the anesthesia code alone. In a combined epidural/general anesthetic, the block cannot be reported separately.
Examples
• A patient having total knee replacement surgery may receive a regional anesthetic and a postoperative pain management agent through the same epidural catheter, in which case the only code reported would be 01402.