Outpatient surgery is here to stay, and given the increasing age and creakiness of the Baby Boomer generation, there are probably plenty more colons to be scoped, knees to be fixed, and so on. How much of that business AmSurg (NASDAQ:AMSG) can make its own, however, remains to be seen.

The fourth quarter was rough, as AmSurg had expected. Total revenue was up a nice-looking 18%, though same-facility growth was only 1%. Even adjusting that last figure to account for a difference in the calendar between the two quarters brings it up to just 3% -- a level that's tough to get excited about. Operating income rose just 10%, and reported net earnings actually dropped a bit from last year.

Although AmSurg is still a leading player in ambulatory surgical centers in terms of units operated (they run 149, versus 104 at United Surgical Partners (NASDAQ:USPI)), there are some worries now about the basic model. AmSurg's facilities are routinely focused on a single specialty (generally gastrointestinal or ophthalmological), which makes them a bit riskier. Likewise, AmSurg gets more than one-third of its revenue from Medicare or Medicaid. You need only look at the likes of Apria (NYSE:AHG) or Lincare (NASDAQ:LNCR) to see the sort of havoc that can create.

Nevertheless, there are still some attractive aspects to AmSurg's business. Because of its specialization, it can generally undercut hospitals on pricing, and the company is attractive to doctors because it offers more freedom regarding factors like scheduling and product/device choice. What's more, management is not oblivious to the same-facility revenue issue; it seems confident that the company can and will do better. (Management's looking for 3%-4% growth for the next year.)

The stock looks a little tricky. It doesn't seem all that cheap by cash flow, but I'm pretty sure that the stock will head higher if and when those same-facility revenues pick up. Plus, it doesn't hurt to have a reasonably strong trend at your back -- AmSurg's single-specialty focus may increase the risk quotient a bit, but the company appears well-positioned for some pretty significant oncoming demographic changes.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).