Willie Nelson has canceled concerts for the next two months to have surgery for carpal tunnel syndrome, a promoter said.

The 71-year-old country-western star, whose hits include “Whiskey River” and “On the Road Again,” was apparently in so much pain he couldn’t finish a show Saturday in Las Vegas.

“Willie Nelson will have surgery to relieve extreme pain caused by carpal tunnel syndrome,” Carlos Larraz, a promoter with National Artists Corp, said Monday.

Nelson had 10 concerts scheduled for the remainder of May and June. That includes the May 22 date at the Bangor Auditorium and the May 23 date at the Presque Isle Forum. New dates have yet to be announced.