To her grandparents, Michelle Matteson is a 5-year-old medical miracle worth a little self-promotion.
Born with spina bifida, the kindergarten student at Joppatown's Riverside Elementary School had surgery moments after her birth to close the hole in her spine.
Three weeks later, she had surgery to insert a plastic tube -- or shunt -- in her skull to prevent it from filling with fluids and killing her. At age 2, she had surgery to correct visions problems, and in the past year, she has had two procedures to repair the shunt.
For her grandparents, William and Iva Matteson of Edgewood, yesterday was payback time.
Research funded by the March of Dimes developed the shunt that saved Michelle's life, so the Mattesons allowed her to serve as the "ambassador" or poster child for this year's Central Maryland March of Dimes Walk-A-Thon.
The honor meant bringing Michelle, who can walk with crutches, to wave at people along the three Walk-A-Thon parade routes.
"I think it's important to let people know that that's why they're here," said Mr. Matteson as his granddaughter played with a red tubular balloon twisted into the shape of a heart.
This year's Walk-A-Thon, the 24th annual event, attracted about 1,000 participants, but was different than in past years.
Walkers this year could choose one of three routes: a seven-mile hike along the Gwynns Falls Trail, a 4.5 mile walk that began at Poly/Western High School and a harbor walk that began at the Canton Waterfront Park and stretched three miles.
All three routes ended at Oriole Park at Camden Yards, where concession booths were set up to greet participants.
Similar walks will be held Sunday in Anne Arundel, Baltimore, Carroll, Harford and Howard counties.
Candy Blakeslee, March of Dimes communications director, said the multiple Walk-A-Thons are designed to encourage maximum participation. They are expected to attract 10,000 walkers and raise $500,000. The money goes to prevent birth defects and infant mortality through research, community services and education, she said.
The event was moved back to Baltimore this year after it was moved to the suburbs last year for one year because of concerns about increased fees for the police, sanitation and traffic control services.
There also were no criminal incidents, such as the ones that marred the 1990 Walk-A-Thon, when at least a dozen participants suffered minor injuries after being assaulted by a group of teen-age boys in Northeast Baltimore.
Ms. Blakeslee said a heavy police presence and volunteers along the routes may have helped prevent any such problems.
"It's the first year back in the city, and it's been great," she said. "I think everybody had a good time."
Michael Ridings of Columbia came out for the first time to participate with his wife, Debbie, and children, Kelsey, 3, and Nicholas, 6 months.
Other walkers said they had been coming back year after year.
Beverly C. Russell of South Baltimore said she has walked each of the past 23 years. This year, she raised $35 by walking the 3-mile harbor route.
"I feel sorry for all these children," she said. "As long as I can walk and they can't, I'll be here."
To register for the county walks or to get more information, call (800) 927-WALK.