Peter Eisler, USA TODAY

More than a dozen times a day, doctors sew up patients with sponges and other supplies mistakenly left inside. The mistake costs some victims their lives.

Erica Parks knew something wasn’t right in her belly when she left the Alabama hospital that performed her cesarean section in the spring of 2010.

Over the next month, her stomach grew so swollen that she looked pregnant again. By the sixth week, her bowels had shut down entirely. Parks, an Air Force major, staggered in to see her doctor, who sent her immediately to the emergency room.

X-rays showed that a surgical sponge the size of a washcloth had been left in Parks’ abdomen. After a six-hour emergency surgery to untangle the infected mass from her intestine, she needed nearly three weeks of hospitalization.

Parks, now 40, had suffered from what is known officially as a “retained surgical item” — a sponge or instrument left in a patient’s body. Such mistakes are considered so egregious and so preventable that they’re referred to in the medical world as “never events.” They simply are not supposed to happen