The following article was published on cnn.com, some people from the Kruise mentioned that Paul left early to go to see a throat surgeon, it appears to be true:-

KISS lead singer Paul Stanley underwent successful surgery for "recurring vocal cord issues" Tuesday that the musician said Wednesday "come with 40 years of preaching rock 'n' roll."

His doctors say Stanley, who's been touring and recording with KISS for nearly 40 years, will make a "swift and complete" recovery, according to a statement from his publicist. Paul Stanley reflects on KISS "I hold myself to a higher standard than others do," Stanley said. "With that in mind, I wanted to remedy a few minor issues that come with 40 years of preaching rock 'n' roll."

Stanley, 59, is known for his energetic -- and loud -- shows as front man and guitarist for legendary hard rock group.

KISS, one of the longest-running rock acts, stays busy on the road and in the studio. Stanley is producing "Monster," their 20th studio album due out in 2012 as they embark on another global tour.