Question: What is the correct pain block code for an ankle block using the femoral or sciatic nerves? Mississippi Subscriber Answer: You have two options for coding this case: " 64445 -- Injection, anesthetic agent; sciatic nerve,single " 64447 -- ... femoral nerve, single. You should choose between 64445 for the a sciatic nerve and 64447 for a femoral nerve, whichever is most accurate for the procedure your physician performs. As always, be sure his documentation is as complete as possible to accurately report the injection code.