The metal band Slipknot [ tickets ] was forced to cancel its forthcoming U.S. tour after the wife of percussionist Shawn Crahan underwent emergency surgery for treatment of Crohn's Disease.

Her recovery is expected to take six weeks, according to Slipknot's spokeswoman. Crahan, who also goes by No. 6, will stay at home in Des Moines, Iowa, to care for his wife and their three children. Crohn's Disease is a serious inflammatory disease of the gastrointestinal tract.

This is the second false start for Slipknot's tour. It was originally scheduled to begin on Nov. 20 in Green Bay, Wis., but that show was canceled due to "production issues," according to Slipknot’s spokeswoman, making Nov. 21 in Fargo, N.D., the opening night.

Slipknot will make up the shows next spring after it tours Europe, Japan, Australia and Canada. The group, which headlined this fall's Pledge of Allegiance tour, still plans on embarking on a European tour on Jan. 20 in Helsinki, Finland.

The band spent the summer as a main-stage act on the Ozzfest tour.

In August, Slipknot released its sophomore effort for Roadrunner Records, "Iowa." The platinum-selling record debuted at No. 3 on the Billboard 200 album chart.