Clinical trial NCT06412484: State vs. Trait Alterations in Low Back Pain
Official title: Low Back Pain - Disentangling Trait-Like and State-Like Alterations
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Low Back Pain
Keywords: Trait vs. State Alterations
Lead sponsor: Balgrist University Hospital
Sponsor class: OTHER
First posted: 2024-05-14
Enrollment: 80
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CONTROL
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: The study population consists of people that suffer from non-specific low back pain, meaning that their pain cannot reliably be attributed to a specific pathology and radiographic abnormalities correlate poorly with patients' symptoms.

Participants should suffer from chronic episodic low back pain, meaning that they have had back pain pain for at least more than 3 months, with recurrent fluctuating pain episodes.

Brief summary: 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.

Detailed 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.

Eligibility 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

Primary outcomes:
measure: Mechanical Detection Threshold (MDT)
timeFrame: 1 - 6 months
measure: Mechanical Pain Threshold (MPT)
timeFrame: 1 - 6 months
measure: Mechanical Pain Sensitivity (MPS)
timeFrame: 1 - 6 months
measure: Wind-Up Ratio (WUR)
timeFrame: 1 - 6 months
measure: Vibration Detection Threshold (VDT)
timeFrame: 1 - 6 months
measure: Pressure Pain Threshold (PPT):
timeFrame: 1 - 6 months
measure: Sympathetic Skin Responses (SSRs)
timeFrame: 1 - 6 months
measure: Conditioned Pain Modulation (CPM)
timeFrame: 1 - 6 months
measure: Brain resting state Magnetic Resonance Imaging (rsMRI)
timeFrame: 1 - 6 months
measure: Lumbar Magnetic Resonance Imaging
timeFrame: 1 - 6 months
measure: Brain Magnetic Resonance Spectroscopy (MRS)
timeFrame: 1 - 6 months
measure: Blood Sample
timeFrame: 1 - 6 months
Secondary outcomes:
measure: Anxiety and Depression
timeFrame: 1 - 6 months
measure: Pain Catastrophizing
timeFrame: 1 - 6 months
measure: Pain Sensitivity
timeFrame: 1 - 6 months
measure: Pain Self Efficacy
timeFrame: 1 - 6 months
measure: Back Awareness
timeFrame: 1 - 6 months
measure: Central sensitization
timeFrame: 1 - 6 months
measure: Widespread Pain Index (WPI)
timeFrame: 1 - 6 months
measure: Symptom Severity Scale (SSS)
timeFrame: 1 - 6 months
measure: Neuropathic Pain
timeFrame: 1 - 6 months
measure: Disability
timeFrame: 1 - 6 months
measure: Pain Extent
timeFrame: 1 - 6 months
Other outcomes:
Locations:
city: Zürich
country: Switzerland
facility: Balgrist Campus
Study officials:
affiliation: University of Zurich
name: Petra Schweinhardt
role: PRINCIPAL_INVESTIGATOR
References: