Spanish surgeons said Monday that they had performed the world's first double-leg transplant, giving an accident victim two new legs. Experts said it will be a month at least before the team will know if the procedure was a success. If the legs should be rejected, however, that will probably happen almost immediately, they said. The still-unidentified patient lost both legs above the knee in an accident. An earlier attempt to fit him with two artificial legs failed because the patient did not have enough of his own legs remaining to use the prostheses successfully. The current operation was approved last year, but surgeons had to wait until they found a suitable donor. Pedro Cavadas, MD, of La Fe Hospital in Valencia began the operation Sunday night, spending nearly 14 hours connecting bones, nerves and muscles in the delicate procedure. Cavadas was the first surgeon in Spain to perform a face transplant, and the first anywhere to include a new tongue and jaw in the procedure.