Stats. Ambulatory surgery isn't ouchless.
D000556:Ambulatory Surgical Procedures / Q000191:economics* / Q000295:instrumentation / Q000706:statistics & numerical data; D003625:Data Collection; D017721:Hospital Costs / Q000706:statistics & numerical data; D006801:Humans; D013523:Surgical Equipment / Q000191:economics* / Q000706:statistics & numerical data; D013525:Surgical Instruments / Q000191:economics* / Q000706:statistics & numerical data; D014481:United States