Shoshana Kovac, 9, of Silver Spring wrote to HOW & WHY to ask about a physical condition called a hernia. Here's what her letter said:

"My brother is going to the hospital for a hernia operation. I have a hernia too, but it's small. I've always wondered how we got hernias, and what they do at the operation, and if it hurts."

Dr. Kurt Newman of the Children's Hospital National Medical Center in Washington knows a lot about hernias. Dr. Newman is a surgeon at Children's.

He explains that a hernia is a pouch of skin containing intestine that has slipped through a gap or weak spot in the muscular wall, which usually holds it in place in the abdomen.

In children, a hernia usually bulges through a weak area in the groin -- the part of the body where the legs join the pelvis. Babies may have hernias that poke out just below their bellybuttons. "Pressure or straining or activity can pop a hernia out," says Dr. Newman.

"We see hernias most frequently in the first year of life," he adds. "Somewhere between 1 and 4 percent of babies have them. In premature babies, hernias are more common.

"Boys have hernias six times more frequently than girls," he adds. "They show up as a bulge in the groin area. The bulge may be there at birth, or it may show up weeks, months or even years later."

Sometimes, older kids like Shoshana's brother need to have hernias repaired. Having a hernia isn't like having an illness, Dr. Newman explains. It's a physical problem, but it doesn't mean anything is wrong with you. "They're not a major deal," says Newman.

Ordinarily, hernias are quite simple to repair by surgery. The patient may not even have to spend the night in the hospital after the procedure.

Once a doctor has diagnosed, or identified, the hernia, he or she will usually recommend that the patient have it repaired. That's because the hernia could develop into a much more serious problem if the piece of intestine became stuck outside of its normal location. Then it might cut off the normal job of the intestines, blocking food from being digested or wastes from being cleared out of the body.

"Hernia repairs in healthy children can usually be done on an outpatient basis," says Dr. Newman. "That means you have the operation and go home in the afternoon if everything goes O.K."

Having a hernia operation may not even leave a visible scar. The surgeon makes a small incision, or cut, along the natural folds of skin in the groin area.

Dr. Newman explains what happens during the operation: "Once we make the incision, we go find the hernia sac -- the place where the piece of intestine is coming out of the abdomen -- and push the piece back inside where it belongs. Then we tie off the hernia sac and remove it. The procedure usually takes about 30 minutes, including the time it takes to go to sleep from the anesthetic."

Afterward, Dr. Newman says, the patient may feel groggy and sore. But those feelings will wear off quickly. The patient will need to see the doctor again to make sure everything's healing right. "All the stitches are on the inside, so down the line there's nothing to remove," says Dr. Newman.

"Within a day or two, the babies we operate on seem to feel just fine," the surgeon says. "A 9-year-old might feel sore for a few days because there's more stretching of the muscles during the operation. When he leaves the hospital, he might feel more comfortable getting to his parents' car in a wheelchair. We'd give him mild pain relievers for the discomfort. But he'd be back in school in a week, and only out of gym class for a couple of weeks after that."

Tips for Parents

Any hospital procedure -- especially one involving general anesthesia -- can be frightening for young children. Prospective surgical patients at Children's Hospital National Medical Center take part in activities -- including a puppet show -- designed to introduce them to the hospital and deal with some of their fears. For information on the program, contact the Child Life Department at Children's Hospital, 111 Michigan Ave. NW, Washington, D.C. 20010; 745-2062.

For more information on how to prepare a child for a hospital experience, contact the Association for the Care of Children's Health, 3615 Wisconsin Ave., NW, Washington, D.C. 20016; 244-1801. The ACCH publishes excellent booklets designed to help both parents and kids cope with surgery, as well as annual lists of recommended books for children on hospitalization and illness.

Catherine O'Neill is a free-lance children's writer in Baltimore.