Neck Specific Research

 

It’s because back pain worldwide is about 2.5 times as big a problem as neck pain, that it gets the lions share of the research. That’s all well and good unless you have neck pain, which is still the world’s fourth leading cause of suffering. Most spine researchers and practitioners alike have more or less assumed that the treatment and principles for the back apply to the neck, and I do not think they are wrong for doing so. And when there is no guidance one way or the other, that’s what I do as well.  I think it’s a much better assumption to make than to either “just make things up” or remain action-less in skeptical agnosticism.

While I think the bulk of the research I present in relation to back pain does apply to neck pain, here’s where I’ll park my neck-specific research that either confirms or denies that assumption, or is otherwise interesting. So without further ado:


NECK FLEXION MOST IMPORTANT RISK FACTOR FOR NECK PAIN

Work-related psychosocial and mechanical risk factors for work disability: a 3-year follow-up study of the general working population in Norway. Sterud T. Scand J Work Environ Health. 2013 Sep 1;39(5):468-76. [free full text]

“Mechanical factors were neck flexion (OR 2.49, 95% CI 1.36-4.56), prolonged standing (OR 1.79, 95% CI 1.21-2.46), whole-body vibration (OR 4.15, 95% CI 1.77-9.71), and heavy physical work (OR 2.23. 95% CI 1.08-4.57). The estimated population risk attributable to these factors was about 45%.”

The two most important risk factors for work disability at the population level in the present study were prolonged standing and neck flexion: 21.3% and 11.2% of all disability cases were attributable to these working conditions, respectively. Prolonged standing has some support in the literature as a risk factor for work disability and reduced work ability, whereas neck flexion has been shown to increase the risk of neck pain and sick leave associated with neck pain.”

My comments: 

Studies looking at work-related injury and risk factors are usually a bit iffy because it is difficult to sort out the various causal factors. In bio-mechanical research they can just put a spine in a jig, measure the amount and direction of force, count the reps and see what happens. Unfortunately all that research has been done on lumbar rather than cervical vertebra. Well, technically Stuart McGill’s bio-mechanical research is done on pig cervical vertebra, but only because they are shaped and act so much like human lumbar vertebra that orthopedic surgeons have been unable to tell them apart. However, this study specifically looked at prolonged neck flexion, among other forces, and found it one of the strongest predictors of work disability.


TODAY’S NECK POSTURE AFFECTS FUTURE WHIPLASH, FUTURE PAIN

Effects of abnormal posture on capsular ligament elongations in a computational model subjected to whiplash loading. Stemper BD, Yoganandan N, Pintar FA. J Biomech. 2005 Jun;38(6):1313-23.

From the paper:

“Under the normal posture, greatest elongations occurred in the dorsal anatomic region at the C2-C3 level and in the lateral anatomic region from C3-C4 to C6-C7 levels. Abnormal postures increased elongation magnitudes in these regions by up to 70%. Excessive ligament elongations induce laxity to the facet joint, particularly at the local regions of the anatomy in the abnormal kyphotic posture. Increased laxity may predispose the cervical spine to accelerated degenerative changes over time and lead to instability. Results from the present study, while providing quantified level- and region-specific kinematic data, concur with clinical findings that abnormal spinal curvatures enhance the likelihood of whiplash injury and may have long-term clinical and biomechanical implications.”

“During inertially applied (non-contact) dynamic loading, it was reported that whiplash injury severity significantly depends upon the cervical curvature; patients with pre-existing abnormal curvatures demonstrate greater injury severity with higher levels of morbidity.”

“Chronic illness is also reported to be associated with spinal posture. Five years after sustaining whiplash injury, patients with abnormal cervical curvature at the time of injury demonstrated higher incidence of degenerative changes in the spine.”

“Maximum facet joint capsular ligament elongation in the present study approached 2.0 mm in the normal posture and 3.3 mm in the kyphotic posture. This magnitude of stretch would cause subcatastrophic capsular ligament failure. These subcatastrophic injuries can initiate a noxious (pain) response.”

“Governmental research reported that head restraints decreased the overall risk of neck injury by only 5–20%. These studies imply that the whiplash injury occurs prior to head restraint contact, i.e., during the retraction (S-curvature) phase.”

My comments:

What’s interesting about this study is not just that abnormal neck postures (forward head posture) are harmful in and of itself, but that it leaves your head hanging in the wind (literally) if you are involved in a car accident. Your head being further from the headrest means in a rear impact, there will be further strain and motion before your muscles or the headrest can catch you. Abnormal neck posture results in over 70% increase in cervical ligament strain, which then sets you up for increased pain down the road. This is where the neck centering aspect of Spinal Flow Yoga™ has application even if you are doing Spinal Flow™ for low back pain. Prevention is honestly way better than treatment, not to mention you’ll be taller and more attractive while you’re at it.

Chad Reilly, Physical Therapist and developer of Spinal Flow Yoga™

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