The medical device tax has been under seemingly constant attack since the Affordable Care Act -- also known as Obamacare -- was passed in 2009. Senate Republicans have recently renewed their calls for its repeal, citing a bipartisan (non-binding) resolution calling for its repeal that the Senate overwhelmingly passed last year. No decision has yet been reached about if and when a vote would occur, so investors will definitely want to stay tuned to this critical Obamacare story.

We'll leave the political predictions and commentary aside -- we're investors. So, how much does this tax matter to publicly traded medical device stocks, companies like St. Jude (NYSE:STJ)Boston Scientific (NYSE:BSX), and Medtronic (NYSE:MDT)? You would imagine that the 2.3% excise tax will add...2.3% to costs. But the picture gets a bit more complicated when you consider the various carve-outs and exceptions to the rule. And the impact may vary by the size of the company.

In the video below, Motley Fool health care analysts Michael Douglass and David Williamson dig into the data and look at this Obamacare tax and its effect on the crucial medical devices industry.