A patent-shielded technological moat can give a company a long time to exploit the niche in which it dominates. When the company runs out of new sub-markets where the technology applies, that's the end of the golden age.

For Intuitive Surgical (Nasdaq: ISRG), that day keeps moving further away.

The robotic surgery veteran, created in a landmark 2002 merger between the only two serious competitors in the field, is busy finding new applications for its robotic tools. So far, the bulk of the procedures completed with the help of the da Vinci toolset have been of the urological and gynecological classes. This makes perfect sense as the Food and Drug Administration approved those uses early on. Now, head and neck cancers can be removed robotically, with benefits and success levels great enough that the respected Henry Ford clinic brags about its procedures in press releases, after being approved as recently as January.

Surgeries that would typically mess up your voice for six months or longer while requiring that you eat dinner through a straw now result in full recoveries most of the time. With about 45,000 diagnoses per year in the U.S., this is not as huge a market as the prostatectomies, cardiac valve repairs, and gastric bypass surgeries that made da Vinci and Intuitive Surgical famous. But every little bit helps. This success is paving the way for trials of sleep apnea treatments and general procedures in the throat and mouth. And it's just one of the several areas where Intuitive Surgical sees future potential growth.

If Intuitive Surgical has any competition, it would be from a bunch of relatively tiny operations that the company could swallow whole: Accuray (Nasdaq: ARAY) is the only one large enough to mention. As for larger competitors itching to buy their way into robotic surgery, Intuitive Surgical has become too large and expensive for most of them. Medtronic (NYSE: MDT) could make a severely dilutive stock-swap offer, perhaps, or Stryker (NYSE: SYK) could attempt a merger of equals. Both seem highly unlikely.

So after carving its way into our hearts and portfolios, Intuitive Surgical is still exploring many new fields. Access to the entire human body is still a long way off, which leaves plenty of room for fresh growth.

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Fool contributor Anders Bylund holds no position in any of the companies discussed here. Stryker is a Motley Fool Inside Value selection. Intuitive Surgical is a Motley Fool Rule Breakers recommendation. The Fool owns shares of Medtronic. Try any of our Foolish newsletter services free for 30 days. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.