42 CFR §416.65

1. (a)General standards. Covered surgical procedures are those surgical and other medical procedures that—
   1. (1)Are commonly performed on an inpatient basis in hospitals, but may be safely performed in an ASC;
   2. (2)Are not of a type that are commonly performed, or that may be safely performed, in physicians' offices;
   3. (3)Are limited to those requiring a dedicated operating room (or suite), and generally requiring a post-operative recovery room or short-term (not overnight) convalescent room; and
   4. (4)Are not otherwise excluded under § 411.15 of this chapter.
2. (b)Specific standards.
   1. (1)Covered surgical procedures are limited to those that do not generally exceed—
      1. (i)A total of 90 minutes operating time; and
      2. (ii)A total of 4 hours recovery or convalescent time.
   2. (2)If the covered surgical procedures require anesthesia, the anesthesia must be—
      1. (i)Local or regional anesthesia; or
      2. (ii)General anesthesia of 90 minutes or less duration.
   3. (3)Covered surgical procedures may not be of a type that—
      1. (i)Generally result in extensive blood loss;
      2. (ii)Require major or prolonged invasion of body cavities;
      3. (iii)Directly involve major blood vessels; or
      4. (iv)Are generally emergency or life-threatening in nature.
3. (c)Publication of covered procedures. CMS will publish in the Federal Register a list of covered surgical procedures and revisions as appropriate.