Cuban leader Fidel Castro chose to avoid a colostomy and opted for riskier intestinal surgery that led to serious complications, the Spanish newspaper El Pais said in its Wednesday edition.
The shortcut involved sewing the colon to the rectum but did not heal properly and broke apart, releasing gastric fluid with feces that caused serious infection, El Pais said on its website.
The newspaper reported a day earlier that Castro's prognosis was "very serious" and that he is being fed intravenously after three failed operations for diverticulitis, or pouch-like bulges in the large intestine that get infected.
El Pais cited medical sources at the same Madrid hospital where a surgeon who examined Castro in late December works.
The 80-year-old leader has not been seen in public since late July, when he was rushed to surgery and ceded power to his brother Raul for the first time since Cuba's 1959 revolution.
A colostomy, the usual procedure for diverticulitis after removing part of the intestine, is an opening in the abdomen to release stool into an external bag. A second operation is required to rejoin the intestine.
"Castro and his entourage, according to medical sources close to the case, rejected this approach because they considered it uncomfortable and did not want him to undergo a second operation," El Pais said.
The advantage of the shorter procedure was that Castro could have been back on his feet within days if it had worked, the paper said.
Instead, he suffered a second peritonitis, or infection, requiring two further operations, it added.
The Spanish surgeon who examined Castro, Dr Jose Luis Garcia Sabrido, said on his return to Madrid that the Cuban leader needed no further surgery and was recovering slowly.
On Tuesday, his secretary said he had not changed his outlook for Castro's recovery.
Castro's prolonged absence and the secrecy surrounding his condition in Cuba has fueled speculation he is so ill he may never return to power.
US doctors said Tuesday's report in El Pais suggested Castro had received questionable or even botched care.
"It sounds like they tried to spare him the colostomy, which would have been the safer and more conservative approach," said Dr Meyer Solny, a gastrointestinal expert at New York Presbyterian Hospital.