Barring any other radiographic abnormalities, a straight neck may be a major anatomical aberration in fibromyalgia that has gone unnoticed.

Robert Katz, MD, spoke with Physician’s Weekly about a study he and his colleagues had published in the Journal of Clinical Rheumatology, titled “The Vast Majority of Patients With Fibromyalgia Have a Straight Neck Observed on a Lateral View Radiograph of the Cervical Spine: An Aid in the Diagnosis of Fibromyalgia and a Possible Clue to the Etiology.”

PW: Can you briefly explain what you and your colleagues sought to determine with this study? 

 Dr. Katz: Until recently, our office had X-ray facilities, and I used to read the radiographs. I noticed that all patients with fibromyalgia had normal X-rays, but they tended to have a straight cervical spine, so we decided to measure the cervical spine angle, called the Cobb angle, and compare it to patients with other rheumatic diseases. We conducted a blinded study of a consecutive series of 270 cervical spine radiographs of female patients in which the physician reading the X-rays and measuring the Cobb angle using computer software was not aware of the patient’s diagnosis. This is relatively easy to do because radiographs do not have a diagnosis attached to them. We determined whether the cervical spine X-rays looked normal, focusing on the lateral view, and then we measured the Cobb angle in patients without knowing the underlying rheumatic disease diagnosis.

PW: What findings from your study are important to stress to our readers, particularly rheumatologists?

Dr. Katz:  Our study consisted of 155 adult female patients with fibromyalgia and 115 adult female controls with a rheumatic disease other than fibromyalgia. We observed that in 83.2% of patients, the cervical spine was  straight, with a Cobb angle of 10 degrees or less. In patients with fibromyalgia, the loss of cervical curvature was about 6.5 times greater compared with that of control subjects (50.3% vs 7.8%; Table).

Fibromyalgia is an invisible illness. As rheumatologists, we see a lot of it. Patients present with widespread subjective pain but there were, until recently, no objective diagnostic markers. A straight neck, without any other radiographic abnormalities, is one of them, however. If you order cervical spine radiographs and you look at them yourself without relying on the radiologist, you will see that in most cases, the neck is straight in the lateral view. The normal reverse C configuration is missing, which is an important marker because it may also suggest potential etiology of the illness as well as help with the diagnosis.

PW: What are the implications of your research and how would you like to see rheumatologists incorporate your findings?

Dr. Katz: I would like to see future studies validate our findings, verifying the results of the straight spine and allowing others to suggest the potential etiology, including my observation of increased muscle pressure. Muscle pressure was almost three time higher in patients with fibromyalgia as indicated by a pressure gauge, and muscle biopsies performed years ago showed normal muscle tissue but hypoxia. The straight neck on an X-ray could be due to increased muscle tension and pain could partially be due to high muscle pressure and hypoxia. If increased muscle pressure and the straight neck are confirmed, higher doses of muscle relaxants, administered primarily at night so it does not affect daytime alertness and nighttime sleep patterns, might be beneficial.

Generally, a bias exists in prominent rheumatology medical journals against fibromyalgia research, although a recent study reports the prevalence of fibromyalgia to be in the range of 3.4% to 5.7% of the global population. Although this is an extremely prevalent disease, there is very little research on fibromyalgia. We need to address fibromyalgia in terms of understanding it and find better treatments for it rather than trying to avoid understanding it.