Posted Dec 3, 2011
A new study found that more than half of the people undergoing spinal fusion surgery had inadequate levels of vitamin D, a condition that doctors say might reduce their chances of having successful back surgery.
The research involved 313 adults undergoing fusion surgery at Washington University in St. Louis in 2010 and 2011. Their blood levels of vitamin D were tested before surgery.
A total of 57% of the patients had inadequate vitamin D levels, defined as a blood level of less than 30 nanograms per milliliter. Of those, 27% had deficient vitamin D (less than 20 ng/ml) and 4% had a severe deficiency (less than 10 ng/ml).
“It was alarming to see that so many patients have inadequate or deficient vitamin D levels, especially when vitamin D is so readily available and inexpensive,” said lead author Jacob Buchowski, an associate professor of orthopedic and neurological surgery at Washington University. “It’s really the deficient patients we worry about.”
The paper, presented Thursday at the North American Spine Society annual meeting, is the latest in the ongoing controversy about vitamin D and whether people should be supplementing their diets with vitamin D pills.
A substantial amount of observational research has suggested that supplementation may reduce the risk of a variety of diseases, ranging from cancer to heart disease as well as more established bone health benefits.
However, last November the Institute of Medicine concluded that most Americans don’t need to take large amounts of vitamin D or calcium to maintain bone health. It also said there was not sufficient evidence to support other claims about vitamin D supplementation and disease prevention.
For bone health, most people need about 400 International Units a day, though those older than 70 may need as much as 800 IU daily, the institute said.
Proponents say that people living in northern latitudes often make inadequate levels of vitamin D from the sun and that it is difficult to get optimal levels from food.
D is needed to make bone
Doctors say spine surgery patients may represent a special class of people when it comes to vitamin D because successful spinal fusion requires making new bone.
Without vitamin D, “you won’t make bone or the bone you make will be inadequate,” said Christopher Kauffman, an orthopedic surgeon at the University Medical Center in Lebanon, Tenn.
Kauffman noted that vitamin D levels are simple to check and inexpensive to fix.
“It seems like common sense, but it’s not something we’re addressing,” he said.
What the study does not show is whether people who are low in vitamin D will improve their fusion rate if they take supplements before surgery.
It also does not show whether maintaining adequate vitamin D levels throughout life will reduce the incidence of spine degeneration, said Dennis Maiman, chairman of neurosurgery at Froedtert Hospital and the Medical College of Wisconsin.
Maiman said he does not think all back surgery patients need to have their vitamin D levels checked, but it probably is a good idea to check those who are at risk for having low levels. That would include people older than 55 and those with a history of smoking, obesity and diabetes, he said.
Buchowski said the idea of checking vitamin D levels of patients first occurred to him in 2008. A woman in her 40s who had undergone cervical fusion surgery and did not get an adequate fusion told him that she had been treated for a vitamin D deficiency.
“It was like a light bulb went off,” he said.
For the last year and a half, all patients undergoing fusion surgery at Washington University have their vitamin D levels checked.
If they are deficient, they will be supplemented with a 50,000 IU prescription dose once a week for eight weeks before their surgery, he said.
“That usually gets them into the normal range,” he said. “Having a spine fusion is a big deal. I want to do everything I can to improve outcomes.”
The researchers said that while older adults are more likely to have low vitamin D levels, younger adults undergoing spine surgery should not be overlooked.
©2011 the Milwaukee Journal Sentinel