By: Deed E. Harrison, DC
Chronic cervical spine disorders is one of the leading causes of disability across nations and cultures.1 There exists an opinion in the spinal health literature that the presence and extent of the cervical sagittal plane curve is unrelated to spine pain conditions and patient health.2 However, in this author’s opinion, the number and quality of studies is weighted on the positive side of the equation; in other words, there is a correlation between neck pain and related disorders and the cervical curvature.3-6
Background Data Indicates That Cervical Spine Lordotic Curve Correlates to Neck Pain and Disability
Villavicencio et al,3 in their prospective, randomized, double-blind clinical study, enrolled 122 patients who were followed an average of 37.5 months. They3 identified that maintaining a consistent segmental sagittal alignment and increasing cervical lordosis was related to a higher degree of improvement in clinical outcomes as measured with the short-form 36 questionnaire and the neck disability index. Similar findings were identified in the study by Gum et al.4
Figure 1 demonstrates the normal state of the cervical lordotic curvature on the reading left, this person would be expected to have little to no neck related disorders. Then, the sequential loss of the cervical lordotic curve is shown in the consecutive images where progressive development of spinal arthritis and disc disease in different patients over time is shown (Levels 1-4).7
Studies by CBP® Researchers Demonstrate Relationship to Chronic Pain
In two separate cervical spine investigations, McAviney and colleagues5 and Harrison et al.,6 compared the cervical lordosis in chronic neck pain populations to that in healthy participants without a history of neck pain or cervical spine trauma.
- Statistically, persons whose cervical spine curves were below 20° were twice as likely to be in the chronic neck pain group. This finding was not age or gender dependent strengthening these findings.5,6
- Participants with a straightened or reversed cervical curvatures were 18 TIMES more likely to be in the chronic neck pain group as compared to the non-pain group.5
- Thus, a cervical lordosis less than 20° can be considered a type of cervical spine subluxation.
Randomized Trials Indicating Improved Pain, Disability, Neurophysiology
Recently, CBP researchers, lead by Professor Ibrahim Moustafa (Sharjah University, UAE) and Dr. Deed Harrison (CBP NonProfit-Idaho, USA) have completed a series of randomized clinical trials (RCT’s).8-11 These RCT’s were designed to test the hypothesis that structural correction of the cervical sagittal alignment will improve pain, disability, and neurophysiology measurements. Importantly, in two of the RCT’s it was found that restoration of the cervical lordosis towards the 20° magnitude concomitantly improved dermatomal somato-sensory evoked potentials (DSSEP’s)8 and the H-reflex9 in patients with both cervical spine and lumbo-sacral radiculopathy and chronic pain.
In two of the most recent RCT’s by this team of investigators,10-11 the effect of sagittal rehabilitation of the cervical spine on central nervous system latency (velocity) and amplitude was assessed. Correction of the cervical sagittal lordosis and head posture was found to statistically correlate to improvement central conduction time (spinal cord velocity) as measured with the N13-N20 potential. These two break-through RCT’s are the first studies to identify a statistically significant increase in the central nervous system’s conduction velocity resulting from correction of the subluxated cervical spine. Noteworthy, is the fact that traditional conservative interventions did not improve sagittal alignment and did not improve neurophysiology even though they were associated with temporary pain and disability improvements. Only the group receiving CBP extension traction methods were found to have statistically significant improvement in spine alignment, neurophysiology, and long-term pain and disability outcomes.8-11
- Noormohammadpour P. Prevalence of Chronic Neck Pain, Low Back Pain and Knee Pain and their Related Factors in Community-dwelling Adults in Iran: A Population-based National Study. Clin J Pain 2016 Jun 1.
- Christensen ST, Hartvigsen J. Spinal curves and health: a systematic critical review of the epidemiological literature dealing with associations between sagittal spinal curves and health. J Manipulative Physiol Ther. 2008 Nov-Dec;31(9):690-714. doi: 10.1016/j.jmpt.2008.10.004.
- Villavicencio AT, etal. Prospective, randomized, double-blind clinical study evaluating the correlation of clinical outcomes and cervical sagittal alignment. Neurosurgery 2011 May;68(5):1309-16; discussion 1316.DOI:10.1227/NEU.0b013e31820b51f3.
- Gum JL, et al. Correlation between cervical spine sagittal alignment and clinical outcome after anterior cervical discectomy and fusion. Am J Orthop (Belle Mead NJ) 2012 Jun;41(6):E81-4.
- McAviney J, Schulz D, Bock R, Harrison DE, Holland B. Determining the relationship between cervical lordosis and neck complaints. J Manipulative Physiol Ther. 2005 Mar-Apr;28(3):187-93.
- Harrison DD, Harrison DE, Janik TJ, Cailliet R, Haas JW, Ferrantelli J, Holland B. Modeling of the Sagittal Cervical Spine as a Method to Discriminate Hypo-Lordosis: Results of Elliptical and Circular Modeling in 72 Asymptomatic Subjects, 52 Acute Neck Pain Subjects, and 70 Chronic Neck Pain Subjects. Spine 2004; 29:2485-2492.
- Harrison DE, Harrison DD, Janik TJ, Jones WE, Cailliet R, Normand M. Comparison of axial and flexural stresses in lordosis and three buckled modes of the cervical spine. Clin Biomech 2001; 16(4): 276-284.
- Moustafa IM, Diab AM, Ahmed A, Harrison DE. The efficacy of cervical lordosis rehabilitation for nerve root function, pain, and segmental motion in cervical spondylotic radiculopathy. PhysioTherapy 2011; 97 Supplement: 846-847. (Link)
- Moustafa IM, Diab AA, Harrison DE. Does improvement towards a normal cervical sagittal configuration aid in the management of lumbosacral radiculopathy: A randomized controlled trial Proceedings of the 13th World Federation of Chiropractic Biennial Congress / ECU Convention, Athens, Greece, May 13-16, 2015. Paper #184 Mediterranean Region Award Winning Paper.
- Moustafa IM, Diab AA, Taha S, Harrison DE. Addition of a Sagittal Cervical Posture Corrective Orthotic Device to a Multimodal Rehabilitation Program Improves Short- and Long-Term Outcomes in Patients with Discogenic Cervical Radiculopathy. Arch Phys Med Rehabil, 2016, 97: 2034-2044.
- Moustafa IM, Diab AAM, Taha S, Harrison DE. Demonstration of central conduction time and neuroplastic changes after cervical lordosis rehabilitation in asymptomatic subjects: A randomized, placebo-controlled trial. Proceedings of the 14th biennial congress of the World Federation of Chiropractic, March 15-18, 2017.