Short answers, pulled from the story.
The Nissen fundoplication is a surgical procedure for treating gastroesophageal reflux disease, named after German-Swiss surgeon Rudolph Nissen. Nissen developed the technique after wrapping folds of a patient's upper stomach around the lower esophagus during a 1936 operation in Istanbul, then formalizing and publishing the results in 1956 after operating on two patients in Basel.
Yes, in December 1948 Nissen admitted Einstein to Jewish Hospital in New York and operated on him. He removed intestinal cysts and also wrapped Einstein's abdominal aortic aneurysm in cellophane to reduce its risk of rupture. Einstein lived several more years after the surgery.
Einstein sent Nissen an autographed newspaper clipping of the famous tongue-out photograph taken after his hospital discharge. The inscription read: "To Nissen my tummy / The world my tongue."
Rudolph Nissen performed the first successful pneumonectomy in the Western world in 1931. He removed the left lung of a 12-year-old girl who had a crush injury to the chest with chronic pus production. Successful pneumonectomy was not reported in the United States until 1933.
Nissen left Germany in 1933 to become head of the surgery department at Istanbul University following Hitler's Jewish boycott. Although he was initially shielded from direct anti-Jewish legislation because of his front-line service in World War I, the broader political environment prompted his departure.
The Rudolf Nissen Prize is awarded by the Deutsche Gesellschaft fur Allgemein- und Viszeralchirurgie, the German Society of General and Visceral Surgery, to recognize surgeons who have advanced the field of gastroenterological surgery. A building at the Charite in Berlin, the Rudolf-Nissen-Haus, was also named in his honor when it opened in 2016.