More than any other technology that has entered the operating room, Intuitive Surgical's (NASDAQ:ISRG) da Vinci system has revolutionized how surgery is performed. The company's stock backs up that sentiment: it's up 2,500% since Intuitive went public in 2000. That's an annualized return of over 26% per year!

However, that's no guarantee the stock will continue climbing. As an Intuitive shareholder myself, I surely hope it will; but part of being a good investor is acknowledging that there will always be pitfalls with your investments.

In that vein, I want to investigate two major reasons Intuitive Surgical's stock could fall in the future.

An early version of Intuitive's da Vinci Surgical System. Source: Nimur, via Wikimedia Commons. .

Hospitals continue tightening budgets
While Intuitive Surgical does a fair amount of business abroad, sales of surgical robots in the United States are still a big part of business.

In 2012, da Vinci system sales accounted for 43% of all company revenue, and over three-fourths of those systems were sold in America. Though average selling prices aren't broken down by region, we can assume that roughly one-third of all the company's revenue came from da Vinci sales in the United States.

Then, after years of healthy growth, that division seemed to come to a screeching halt last year

Source: SEC filings.

Management blamed the Affordable Care Act, or ACA, on the slowdown. Because the legislation is the first of its kind, Intuitive argued, hospitals are uncertain of how it will affect reimbursement rates and overall hospital budgets.

That kind of uncertainty leads to reductions in large capital purchases. And with a price tag of over $1 million, Intuitive's da Vinci Surgical System definitely qualifies as a "large capital purchase."

It remains to be seen if hospitals are gaining more visibility on what their budgets will look like moving forward. Intuitive's management has made it clear  that it doesn't expect the situation to be resolved by the end of the year.

If that uncertainty -- or even worse, certainty that the ACA will forever lower hospital budgets -- continues well into the future, it would severely depress Intuitive's stock price, as a huge section of its revenue base would be under pressure.

Professionals questioning da Vinci's efficacy
In 2013, reports began questioning the efficacy of robotic surgery in benign hysterectomies. At the time, the procedure accounted for the largest percentage of operations in which hospitals used the da Vinci.

Opponents claimed the benefits of using the da Vinci were minimal at best when compared to standard laparoscopic operations. That meant the higher costs incurred by the da Vinci couldn't be justified.

Patrick Clingan, Intuitive's director of finance, recently fired back that certain reports weren't taking the full spectrum of variables into account: "Recently we had seen an increase in [studies] ... that inappropriately select subset in analysis as the basis to draw broad conclusions. We encourage the health care community to demand rigor in these analysis."

If you are an investor in Intuitive, it's worth noting that the results of these studies could significantly determine whether hospitals use or abandon the da Vinci. Over a long enough time frame, it's my firm conviction that Intuitive will be continue refining its technology to make the value of its products clear to all professionals.

However, it must continue drawing in enough revenue to fund these advances. Major problems arising from the da Vinci for any of its core procedures would be a clear blow to shareholders, and that is a risk worth noting.

Brian Stoffel owns shares of Intuitive Surgical. The Motley Fool recommends Intuitive Surgical. The Motley Fool owns shares of Intuitive Surgical. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.