Table 3 Eligibility criteria assessed during case review for Trial 3

Inclusion criteria

Rationale

Neck or neck-related upper limb pain consistent with Quebec Task Force classifications 2 to 4

Neck pain radiating to proximal or distal extremity with or without neurological signs is commonly treated by doctors of chiropractic using study procedures

Naïve to flexion-distraction manual therapy procedures to cervical area

Requires participant unfamiliarity with study interventions

Exclusion criteria

Rationale

Neck pain consistent with Quebec Task Force classifications 1, 5 to 11

Classifications represent diagnoses that may require individualized treatment not available in trial; condition(s) may limit interpretation of study measurements

Bone/joint pathologies representing a contraindication to study procedures, including but not limited to:

1) Inflammatory arthritis involving the cervical spine: i.e., rheumatoid arthritis, systemic lupus erythematosus, etc.

Study prescribed treatments are not intended for these conditions; may require referral and interfere with data collection and interpretation

2) Any condition representing neurological (spinal) instability in cervico-thoracic spine

Condition requires referral for evaluation or care outside study scope

3) Tumors, within or adjacent to the cervico-thoracic spinal canal

Condition requires evaluation or care outside study scope

4) Arnold Chiari malformation

May represent condition requiring referral for evaluation or care and limit interpretation of study measurements

5) Disorders known to exhibit spinal joint hypermobility, such as: Marfan syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta

May represent condition requiring referral; may interfere with data collection and interpretation

6) Cervico-thoracic disc herniation or prolapse demonstrating advancing neurologic deficits

Condition requires referral for evaluation or care outside study scope

7) Sequestered intervertebral disc fragment or loose bodies within the spinal canal, lateral recess, or intervertebral foramen

Safety precaution for available treatment protocols and may require referral

8) Any condition not listed above representing a contraindication to or a safety risk for study procedures

Safety precaution for treatment or biomechanical testing protocols and may require referral

Any single or multisegmental fusion (surgical or congenital) of the first through the seventh cervical vertebrae

Intervention hypothesizes that joint distraction and intervertebral disc pressure change are principal therapeutic mechanisms

Safety precaution (e.g., inability to safely ambulate within clinic, dizziness when arising or lying on treatment table, anxiety from study procedures)

Safety precaution and may interfere with participant’s ability to comply with study protocol

Unable to tolerate study procedures

Safety precaution for treatment or biomechanical testing procedures

Simultaneous management for condition compromising ability to deliver study treatment or assess health status

Safety precaution for treatment protocols and may present an undue scheduling burden

Suspicion of alcohol or drug abuse

May interfere with data collection, ability to comply with study protocol, and requires referral

Cognitive or memory impairment

May prohibit informed consent or compromise safety due to potentially reduced comprehension or compliance with study procedures

Referral for evaluation/management of other condition(s) or further testing required for neck pain diagnosis

Safety precaution and extensive or advanced diagnostic testing outside study scope

Compliance concerns*

May compromise ability to adhere to study protocol