da Vinci Xi patient-side instruments, arms splayed. Source: Intuitive Surgical.

Shares of Intuitive Surgical (NASDAQ:ISRG) surged as much as 12.2% higher in after-hours trading, following the release of strong second-quarter results.

In the second quarter, Intuitive Surgical's non-GAAP sales declined 12% year over year, landing at $507 million. These adjusted revenues exclude $6 million of revenue associated with a guaranteed right of return program for the da Vinci Xi surgical system. The trade-out program was not in effect during the year-ago quarter.

Adjusted earnings declined 19% to $3.73 per diluted share.

Analysts were looking for earnings of $2.83 per share on $502 million in adjusted sales. Intuitive Surgical topped both of these consensus targets.

The company reported a 9% year-over-year increase in worldwide da Vinci-assisted surgeries, driven by general surgery volumes in the U.S. and urological procedures internationally.

Intuitive shipped 96 new da Vinci systems during the quarter, down from 143 systems in the comparable 2013 period and up from 87 systems in the first quarter of 2014. Fifty of this quarter's orders were for the recently introduced da Vinci Xi system.

In prepared remarks, Intuitive Surgical CEO Gary Guthart highlighted a handful of encouraging business trends. "First, global procedures grew 8% on a sequential basis and 9% year over year," he said. "We launched our newest platform, the da Vinci Xi Surgical System and the market reception for it has been very positive. Also during the quarter, we strengthened our direct presence in both Japan and Europe."