A surgeon in Shakopee performed an appendectomy on the same patient twice -- once getting the wrong piece of tissue, the second time after the appendix burst, according to an investigative report released Tuesday by the Minnesota Department of Health.

Investigators found that the surgeon mistakenly removed what was described as a "piece of fat" during the first operation, in April 2008, at St. Francis Regional Medical Center in Shakopee.

The surgeon realized his mistake two days later, when the hospital pathologist reported that the specimen "was not an appendix," the report said. The patient, who had been complaining of pain and fever, was told to return to the hospital for a second operation, when the "true appendix" was removed.

Before his ordeal was over, the unidentified patient spent 11 days in the hospital with complications from the second surgery.

The report was released by the Office of Health Facility Complaints, which investigates complaints against hospitals. In this case, investigators cleared the hospital of any wrongdoing and blamed the surgeon, who was not named. The report said the surgeon no longer works at St. Francis.

Allina Hospitals & Clinics, which co-owns St. Francis, issued a statement saying that "we regret that this incident occurred," and that the hospital had cooperated fully with the investigation.

Surgical errors of this kind are extremely rare. The Health Department, which issues an annual report on hospital errors in Minnesota, found 21 cases of surgeons operating on the wrong body part last year.

According to Tuesday's report, the patient first arrived at the emergency room on April 21, 2008, complaining of pain or pressure in his abdomen. After an initial exam, he was sent home with instructions to return if his symptoms worsened. Seven hours later he did, and tests showed he had appendicitis.

The next day, he had surgery to remove the appendix and was sent home. Investigators later found that no report of that operation was completed.

Two days later, on April 24, 2008, the patient called the surgeon with complaints of persistent pain and fever. That evening, the surgeon called him back to say he had mistakenly removed a "piece of fat" instead of the appendix, according to the patient's medical record.

The second operation didn't start off well either, investigators found.

The surgeon attempted to remove the appendix laparoscopically -- inserting a tube through a small opening. But he changed to an open procedure because of what the report called "visualization concerns." At first, he identified an inflamed piece of tissue that "looked quite a bit like an appendix with appendicitis," the report said, but then found and removed the "true appendix," which had ruptured.

After the operation, the patient suffered an intestinal blockage and other complications, and was hospitalized until May 5, 2008.

The Health Department investigators found "no specific evidence that any actions by the hospital caused this to occur."

Complaints against physicians are handled by a separate state agency, the Minnesota Board of Medical Practice. A spokeswoman said the Health Department routinely forwards such reports to the Medical Board for review, but that the board can't comment on pending cases.

Maura Lerner • 612-673-7384