Sagittal Cervical Alignment Outcomes Are Linked to Pain, Disability, and Neurophysiological Improvements

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. They(3) 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)

Figure 1. Image © Copyright CBP Seminars and Deed Harrison, LLC. Reprinted with Permission. All rights reserved.

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-reflex(9) 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)