TORONTO — More than a quarter of children awaiting surgery at Canadian pediatric hospitals received their procedures beyond the optimal target date, say researchers, noting that extended wait times can adversely affect outcomes in some patients.

The 2007-2009 study by researchers at Toronto's Hospital for Sick Children and the Canadian Paediatric Surgical Wait Times Project was based on more than 64,000 surgeries at Canada's 15 pediatric health centres.

Dentistry, ophthalmology and plastic surgery for cleft lip and palate had the highest percentage of delayed surgeries, followed by cancer, neurosurgery and cardiac operations, researchers report in this week's issue of the Canadian Medical Association Journal.

While 90 per cent of children received their surgeries within six months, 27 per cent did not have their operations within access targets for their particular condition, which were shorter than six months in some cases.

Lead author Dr. Jim Wright, an orthopedic surgeon at Sick Kids and head of the wait times project, said the 90 per cent figure may initially seem reassuring.

"However, very early on in the process, we recognized that setting an access target for surgery is very dependent upon the clinical condition," he said. "So for some clinical conditions, you could wait six months, and you could even argue longer, without any adverse consequences from that.

"However, there are other diagnoses where the interval may be as short as one week or three weeks. So setting a somewhat arbitrary time frame such as six months doesn't really make a lot of sense when you consider the variety of clinical conditions that we're treating."

The study followed the setting up of national maximum wait time targets for about 850 conditions under 11 different surgical disciplines, which were arrived at by a consensus of pediatric specialists country-wide and adopted in 2006.

Delays in surgery can affect children's physical and cognitive development. For example, delaying surgery to correct strabismus -- in which the eyes are crossed or do not focus in the same direction -- risks a child's chances of having normal vision and can affect quality of life.

In a related article, researchers found that waiting beyond six months for surgery to correct scoliosis, or curvature of the spine, in adolescents increases the likelihood of complications and additional surgeries.

Patients who receive spine-straightening operations later than six months may also need longer surgeries, an extended hospital stay and be at higher risk for complications such as increased blood loss, neurologic deficits and inadequate correction of the curvature.

In the study of 216 teenagers who had operations for scoliosis at Sick Kids between November 1997 and August 2005, 88 had waited more than six months for their surgery. Almost 15 per cent of them needed additional surgery due to progression of spinal curvature, compared to less than two per cent of those who had their operations in under six months.

"The highest risks of adverse events due to prolonged wait times occurred in patients who were skeletally immature and had larger curvatures of the spine," writes lead author Dr. Henry Ahn of St. Michael's Hospital in Toronto, who conducted the study with Wright.

Ideally, the surgery should be done within three months of seeing the patient, the wait times project concluded. The operation to correct the curvature, which can become progressively pronounced during the teenaged years, is the most common reason for elective pediatric orthopedic surgery.

"A maximal acceptable wait time that leads to a reduction in the progression of curvature also has the potential to reduce the strain on health-care resources by decreasing the need for additional surgery," Ahn and Wright say in their paper.

But meeting wait-time targets also helps limit anxiety felt by patients, as well as their families, Wright said. "They may have pain related to the underlying condition, they may have functional disability, and then they've got the continual consequences of the progression of the disease."

In the first study, Wright said the researchers were most surprised by excess wait times for such life-threatening conditions as cancer.

"It's an area of significant focus to make sure we get on that right away," he said, adding that neurological surgery is also extremely time-sensitive.

"Children ... have very vulnerable periods of development," he said. "So there's some of these conditions where you need to intercede and do your surgery at particular times, such as the brain is developing -- its ability to hear, its ability to see -- and by doing surgery at critical times, you favourably affect that. And if you wait too long, then it is possible that you've lost that opportunity."

Having national consensus targets will allow surgeons "to triage their patients more appropriately," said Wright, adding that progress in paring down waits is already being made in children's hospitals across Canada.

"The problem of wait times for adults is an important problem (and) it is a huge problem" that the health-care system will likely continue to struggle with for some time, he said. Reducing wait times for children's surgeries is not nearly as daunting a challenge.

"The number of children coming to surgery is a small fraction of the number of Canadians coming to surgery, so for a very modest effort and modest investment, I believe we could lick this problem."