Plans for German Chancellor Angela Merkel to visit Israel at the end of this month were in doubt Friday, as Prime Minister Ariel Sharon underwent more emergency surgery. The German government last month announced plans for the trip, which also was to include meetings with Palestinian representatives. Government spokesman Thomas Steg said that "we will keep the dates free." "At the moment, concern for Ariel Sharon stands in the foreground, as do the wishes for his recovery," Steg said. "A decision today as to whether the planned dates for a trip to Israel, the Middle East, are kept, would be premature _ we will await the developments of coming days."