Stuff to know.

Needles, paper clips, a shard of glass and a crayon are among the items Dr. William E. Shiels II has found embedded in the flesh of his young patients.

Last month, at a meeting in Chicago, the chief of the radiology department at Nationwide Children's Hospital told colleagues about the troubling practice of embedding objects into one's own skin in the interest of self-harm.

The sad truth is that troubled young people find many ways to hurt themselves. Up to 24 percent of high-school students in the U.S. and Canada have intentionally injured themselves, according to recent research.

Cutting, burning and hair-pulling are among the other harmful behaviors that fall into the broad mental-health concern known as self-injury.

It's unclear whether the 10 cases Shiels documented in the past three years are a sign of a national increase in the practice, but they are cause for concern, said Dr. John Campo, chief of child and adolescent psychiatry and medical director of behavioral health at Children's.

"The patients I've seen who engage in this sort of behavior are often quite disturbed young people. They've typically been kids who have a pretty chaotic family history," he said.

"How big of a public-health problem is this right now? I'm not sure we know."

Shiels said that in all of the teenage patients -- nine girls and one boy -- mental illness had been diagnosed before their "self-embedding disorder" was. Most lived in group settings, not with their parents, and had a variety of mental illnesses including depression and bipolar disorder.

The cases are the first Shiels has seen in his 13 years as a radiologist in Columbus, he said. The objects, usually inserted through small cuts in the skin, are removed through small incisions, using ultrasound guidance.

In recent years, cases of self-mutilation, in particular cutting, have increasingly come to the attention of doctors and parents.

One notable difference with the self-embedding cases Shiels has seen is that all but one of the teens reported suicidal thoughts, he said. Other forms of self-injury are not commonly connected to suicidal thoughts or attempts.

He's checked with doctors at hospitals in five cities and all have seen at least one case, Shiels said. Most of the patients embed objects in their arms or legs. All had a history of cutting themselves. They found their way to Children's because of pain or infection, or because they told someone what they'd done.

In general, self-harm is performed in the interest of seeking quick release from emotional distress or pain, said Matthew Selekman, an Evanston, Ill., social worker who specializes in working with those who self-harm and has written two books on the topic.

Their reasons vary and can include self-punishment or a mechanism to take back control when they feel they've lost emotional control because of sexual or other abuse, he said.