A massive rescue operation has brought an injured researcher back to the surface after he spent 11 days trapped in Germany’s deepest cave.

Hundreds of people worked to pull 52-year-old Johann Westhauser out of the Riesending cave complex beneath the Bavarian Alps, where he became stuck after being hit by falling rocks.

Westhauser, an experienced caver, had gone into the Riesending cave system in the Alps with two companions to carry out research and measurements.

Westhauser's condition has been described throughout as stable. Officials didn't elaborate Thursday, but Reindl said he "came through the rescue operation well."

Rescuers had to endure freezing temperatures and cross waterfalls to get to Westhauser, who was trapped 3,200 feet underground and nearly 4 miles from the cave’s entrance.

Crews carried Westhauser on a stretcher wrapped in Styrofoam to protect him against the cold. His head was covered in a helmet, The Telegraph reports.

The last part of the rescue operation involved pulling Westhauser 600 feet up a vertical shaft, using rope.

Rescuers communicated with each other through a radio-based system that allow people underground to send text messages to the surface, according to The Associated Press.

In all, 728 people from Germany, Austria, Switzerland, Italy and Croatia participated in the operation, operation director Klaus Reindl told reporters in nearby Berchtesgaden.

"A chapter of Alpine rescue history has been written here over the last 12 days," Bavarian mountain rescue chief Norbert Heiland said, adding that officials initially doubted whether a rescue was possible.

The rescue became a media event with multi-page spreads in German tabloids.

"Since the birth of caving, there have been only two incidents of this depth, complexity and difficulty," Italian rescuer Roberto Conti said.

A fit expert could climb from the accident site to the entrance in about 12 hours, but rescuers had to haul Westhauser on a stretcher. The cave entrance is on a mountainside, 5,900 feet above sea level.

Bavaria's top security official said he wants to make sure the highly publicized rescue doesn't attract "risk tourism." Interior Minister Joachim Herrmann advocated shutting the cave entrance to ensure it was accessed only by experts.

The Associated Press contributed to this report.