Manual Cervical Distraction: Measuring Chiropractic Delivery for Neck Pain Clinical Trial

We will evaluate the clinician's ability to deliver three randomly assigned manual interventions to the cervical spine within specified traction force ranges (<20 Newtons [N], 20-50N, >50N). The primary outcome of this study is to determine the accuracy and consistency of traction force delivery ranges both between clinicians and within individual clinicians. Traction force ranges (C5 contact level and Occiput contact level) will be measured at each study visit (visits 1, 2, 3, 4, 5) for 2 weeks and averaged to calculate final outcome.

The NDI is a 10-item questionnaire modified from the Oswestry Low Back Pain Disability Index. The NDI has been shown to be a reliable and valid measure of disability due to neck pain, and responsive for measuring change. Study Visit 1 and Study Visit 5 Measures occur 2 weeks apart. The NDI scale is measured on a scale of 0-50, with 0 indicating no disability and 50 indicating complete disability. This measure is an adjusted mean NDI change.

The VAS has excellent metric properties, is easy to administer and score (0-100mm), and is commonly used in pain research. Our anchors will be no pain (score of 0) to worst pain imaginable (score of 100). We will ask participants to rate their current neck pain at baseline and pre-/post-treatment for all 5 study visits. This measure is adjusted mean neck pain VAS change. A single value was calculated by averaging.

The PROMIS-43 questionnaire will be used to measure general functional health status. PROMIS-43 questions measure physical function, anxiety, depression, fatigue, sleep disturbance, social role satisfaction, and pain interference and intensity.

The table below displays the mean score at baseline. On the T-score metric & interpretation:

• A score of 40 is one SD lower than the mean of the reference population (REF POP).
• A score of 60 is one SD higher than the mean of the REF POP.
• For PROMIS measures, higher scores equals more of the concept being measured (e.g., more Fatigue, more Physical Function). Thus a score of 60 is one SD above the average REF POP. This could be a desirable or undesirable outcome, depending upon the concept being measured. For Physical Function and Satisfaction with Social Role, higher scores reflect a better outcome, while for the remaining concepts, higher scores reflect a worse outcome.

PROMIS - Pain Interference adjusted for baseline neck pain VAS.

Cervical ranges of motion are a measure of functional status and can be used to assess dysfunction in the cervical spine. Baseline/visit 1 ("BL") cROM is displayed for Flexion-Extension, Lateral Bending, and Rotation. The mean change in cROM from visit 1 to visit 5 ("V5 change") is also displayed.

We will ask all participants whether they feel the study procedure would relieve their neck pain using the Procedure Believability Questionnaire. The response choices will be: "Strongly believe the procedure will relieve my neck pain; Somewhat believe the procedure will relieve my neck pain; Somewhat believe the procedure will NOT relieve my neck pain; Strongly believe the procedure will NOT relieve my neck pain; and Don't know if the procedure will relieve my neck pain". A baseline (BL) evaluation will be completed based upon treatment description, and compared to assessments following study visit 1 (T1) and study visit 5 (T5) over a 2-week time period.

The CEQ is a quick and easy-to-administer questionnaire for measuring treatment expectancy and rationale credibility of interventions for use in clinical outcome studies. Participants' perceptions of the study treatments were compared across groups using the CEQ. The CEQ credibility factor relates to how logical or believable a treatment is for the patient, whereas the expectancy factor refers to the patient's beliefs about improvements that might be achieved from the treatment [61]. CEQ scores for both the credibility and expectancy factors range from 3 to 27, with higher scores indicating greater belief in treatment credibility or expectancy for clinical improvement.

We will describe electromyographic (EMG) activity of superficial neck muscles during delivery of the three manual interventions during visits 3 and 4. EMG measurements are an exploratory outcome variable in this study.

RMS EMG TREATMENT DESCRIPTIONS:

• (A) Ratio of Root Mean square (RMS) EMG during Treatment at C5/RMS EMG during maximum voluntary contraction (MVC)
• (B) RMS EMG during Treatment at C5/RMS EMG during Prone Resting
• (C) RMS EMG during Treatment at Occiput (OCC)/RMS EMG during MVC
• (D) RMS EMG during Treatment at OCC/ RMS EMG during Prone Resting

MUSCLES:

• LES-Left erector Spinae Muscle
• RES-Right Erector Spinae Muscle
• LTRPS- Left Trapezius muscle
• RTRPS- Right Trapezius Muscle
• LSCM- Left Sternocleido Mastoid muscle
• RSCM- Right Sternocleido Mastoid Muscle

ACRONYM KEY:

• RMS-Root Mean Square Value
• MVC-Maximum Voluntary Contraction
• C5-Cervical vertebrae contact
• OCC-Occipital contact
• EMG-Electromyographic activity

Participants' satisfaction with study procedures and staff were assessed at Study Visit 5 using standard questions. Participants rated their satisfaction with various elements of the study (e.g., treatments received, clinicians) using a 5 category response from 1 (strongly satisfied) to 5 (strongly dissatisfied) with categories collapsed into satisfied (categories 1 and 2) or not satisfied (categories 3, 4 or 5) for interpretation.