State vs. Trait Alterations in Low Back Pain

Schweinhardt Petra

Status: Enrolling

Conditions: Low Back Pain

Treatments: Behavioral: Experimental Pain Session (= clinically irrelevant pain); Behavioral: Low Back Pain Session (= clinically relevant pain); Behavioral: Pain Free Session

Study type: Observational

Funder types: Other

Identifiers

NCT06412484

CRPP Renewal

Details and patient eligibility

About

The primary goal of this study is to investigate whether different alterations observed in patients with non-specific episodic low back pain (compared to healthy volunteers), detected using several assessments: psychophysical and neurophysiological testing, imaging, and blood sampling, are dependent or independent of the presence and type of pain experienced at the time of investigation.

Full description

The study consists of three visits (healthy volunteers will only have one pain-free visit), in which patients will be tested in a different "pain state" at each visit:

1. Pain-free visit: will be carried out when the patients have no or little (Numerical Pain Rating Scale (NPRS) </= 2/10) clinical pain.
2. Clinically relevant Low Back Pain visit: will be carried out with patients experiencing a low back pain episode with an intensity of 3/10 or more on the NPRS.
3. Experimental pain / Clinically irrelevant pain visit: will be carried out with the application of a high concentration (8%) Qutenza® capsaicin patch at the arm.

Each of the visits will consist of psychophysical testing, neurophysiological assessement of sweat activity in response to pain, brain resting state magnetic resonance imaging and magnetic resonance spectroscopy. Additionally, and depending on the type of session, a lumbar spine magnetic resonance image (only pain-free session, as characterization) and a blood sample (only pain free and low back pain visit) will be performed.

Enrollment: 80 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria:

• German or English proficiency
• Informed consent
• Low back pain for more than 3 months
• Low back pain clinically not attributable to "red flags" (e.g. infection, fractures, inflammation)
• Fluctuating course of pain (with on and off pain periods).

Exclusion Criteria (applicable to both groups):

• Inability to give informed consent / follow study instructions (e.g. due to language problems)
• Major medical or psychiatric condition. E.g. severe heart disease, diabetes, autoimmune disorders, rheumatic disorders, major depressive disorder, etc.
• Symptomatic radiculopathy, manifested through motor and/or sensory deficits / or signs of nerve root involvement on lumbar MRI.
• Back operation
• BMI > 30
• Pregnancy

Trial design

80 participants in 2 patient groups

Low Back Pain (LBP) Patients

Description:

LBP patients will undergo three study visits, at moments at which their pain status is different: a) "pain-free", b) low back pain (clinically relevant), c) experimental pain (clinically irrelevant). Measures will be repeated in each visit, to understand the influence / relationship of pain state on possible mechanistic alterations observed in LBP compared to HCs.

Treatment:

Behavioral: Pain Free Session

Behavioral: Low Back Pain Session (= clinically relevant pain)

Behavioral: Experimental Pain Session (= clinically irrelevant pain)

Healthy Controls (HCs)

Description:

HCs will undergo one single visit, equivalent to patients' "pain-free" visit.

Treatment:

Behavioral: Pain Free Session