It began like any typical late summer day. Three-year-old Lilith and her mom were playing outdoors near their home in Concord, New Hampshire, when the little girl suddenly screamed in pain. As her mother called for help, she collapsed to the ground.

At first, emergency doctors believed Lilith had experienced an allergic reaction to an insect sting. After giving her a shot of epinephrine, they placed her in a medically induced coma to heal. But when she woke, Lilith wasn't any better. In fact, she couldn't sit up or move her arms. Something far more serious than a simple insect sting was at work.

A series of MRI scans revealed a frightening diagnosis: an arteriovenous fistula (AVF) in her spinal cord. AVFs are rare malformations that occur when arteries connect directly to veins, increasing the chance of potentially life-threatening bleeding. In Lilith's case, the AVF had already begun to hemorrhage and required immediate treatment.

Lilith's doctor in New Hampshire referred her parents to Dr. Darren Orbach, co-director of the Cerebrovascular Surgery and Interventions Center at Boston Children's Hospital and an expert in a minimally invasive technique called pediatric endovascular embolization. This approach uses a catheter (a thin, flexible tube) to inject various glue-like compounds into the affected blood vessel or insert tiny devices to close off the fistula.

The procedure was a success — but only time would tell if Lilith would fully regain her mobility.

Incredibly, she's exceeded all expectations: Following six weeks at a local rehabilitation unit, she's reclaimed about 95 percent of her mobility — a dramatic recovery. Today, Lilith is more independent than ever, insisting on climbing stairs and doing other activities without help.

"It's like she remembers when she couldn't do these things," says her mom. "Now she knows she can do anything if she tries."