Here is a excerpt from one of the most recent studies :
Two studies that have come out recently said that there is no evidence that the force or direction utilized in cervical manipulation reaches the threshold of stretching the arteries to the point that they can be damaged," he said, adding that professionals who perform neck adjustments apply force that is "no greater than what people can do in activities of daily life."
Overland added that neck manipulation is associated with many fewer stroke deaths than other common medical treatments for neck pain.
Neck manipulation is associated with about one death per 1 million people due to cervical artery dissection, he said.
By comparison, nonsteroidal anti-inflammatory drugs (NSAIDs) cause 153 stroke deaths per 1 million people, narcotic medications cause 53 stroke deaths per 1 million people, and spinal surgery of the neck causes 500 stroke deaths per 1 million people, Overland said.
"We are concerned that a statement like this can possibly create a fear in a patient, preventing them from making a choice of treatments that may in fact turn out to be the safest choice of all for their neck pain or headache," he said