Forget the consultants- they will say anything to get your business and are operating on old dated pricing data that do not include the definite trend of site of service differential payments and the trend of cost plus pricing for expensive disposables such as SCS trial leads. Some insurers want the invoices for expensive disposables now and are paying 5-6% over the invoice cost which is not enough to run an ASC.
Advantages of an ASC currently: still can be profitable but many codes are no longer paid in ASCs (most insurers will not pay any 62287 discectomy code any longer, Medicare does not cover discograms or vertebroplasty in an ASC, etc). The main advantage is autonomy from the hospital rather than $$ at this point in time. 3 years ago the landscape and outlook for ASCs was completely different with respect to pain management. Now insurers are increasingly denying payment for standard pain procedures such as RF or ESI unless stringent criteria are met.
Disadvantages of ASC: Huge outlay of 500,000 to 1.5 mil up front unless you use a consultant/management/partner. In the latter situation, you cede control. The future for pain management in expensive procedures is quite bleak therefore you must ask...do I really need an ASC and all the scheduling/politics/financial/personnel/equipment headaches? If you are considering a multispecialty ASC, then that is different since that spreads the tremendous financial risk around to more stable specialties with a stable pricing in ASCs.
If you have 30-50% Medicare, forget building a single specialty ASC since they are money losing ventures compared to doing the same procedures in your office. They day of the $1500 ASC charge for an epidural is nearly gone...don't get sucked into rhetoric of highly paid consultants who are using past data (when ASCs could collect that much money) to render their future projections.