Experts are warning that manipulating the upper spine during back treatments could be dangerous.
According to a review of studies spinal manipulation should not routinely be done on patients and can result in serious injury.
The experts say when such manipulations are performed on the upper spine, it can result in serious and possibly fatal complications, such as stroke and even death.
Spinal manipulation or adjustment is a manual treatment where a vertebral joint is passively moved between the normal range of motion and is often used by osteopaths, physiotherapists and physicians, and is the signature treatment of chiropractors.
Although the aim is to supposedly adjust the small joints between the bones to help relieve any pain and stiffness, some studies have suggested the problems can be made worse by the technique.
Several studies have identified a link between routine spinal manipulation when the cervical vertebrae are involved and risk of adverse effects but it is not uncommon for serious adverse effects not to be reported in the medical literature.
Lead researcher Edzard Ernst, Professor of Complementary Medicine at Peninsular Medical School, Universities of Exeter and Plymouth, says even allowing for an extraordinarily high level of under-reporting, spinal manipulation has been associated with about 600 serious adverse events.
Professor Ernst says it also causes non-serious adverse effects in about 50 percent of all patients who use it and he suggests that were any drugs linked to such rates of harm he doubts they would remain on the market.
The researchers examined 36 cases and reports and found that more than 200 patients were suspected to have been seriously harmed and they believe this is just the tiny tip of a very large iceberg.
It appears clear evidence was found of adverse events, from low level pain to disc herniation, bone fractures, spinal cord injury and stroke.
Dr. Kamran Abbasi, editor of the JRSM, says the central issue here is ensuring that sufficient high-quality evidence is available for patients, so that they can make an informed decision before beginning any therapy.
The research is published in the Journal of the Royal Society of Medicine (JRSM).