Offset Mechanisms in Evaluation of Lumbar Medial Branch Blocks

Study Overview
=================
Brief Summary
-----------------
This study examines the relationship between central nervous system (CNS) mechanisms of pain inhibition and the pain relief that occurs following a lumbar medial branch block (MBB).

Detailed Description
-----------------
This study examines the relationship between central nervous system (CNS) mechanisms of pain inhibition and the pain relief that occurs following a commonly-performed nerve block used to diagnose and treat chronic low back pain. Patients scheduled for lumbar medial branch blocks as part of routine clinical care will arrive to clinic prior to the block for quantitative sensory testing procedures that measure CNS pain modulation. Patients will then undergo treatment as usual with their block, subsequently reporting low back pain intensity in a pain diary.

Official Title
-----------------
OMEGA Study: Offset Mechanisms in Evaluation of Lumbar Medial Branch Block

Conditions
-----------------
Pain, Chronic, Facet Joint Pain, Pain, Procedural, Analgesia

Intervention / Treatment
-----------------
* Behavioral: Cutaneous Probe
* Behavioral: Quantitative Sensory Testing
* Behavioral: Computer Tasks


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Scheduled for lumbar MBB in UPMC Pain Management clinics Age > 18 years old Predominantly axial chronic low back pain at least 3 months on a daily basis Must meet the minimum criteria for cognitive function using the PROMIS 2-item cognitive screener (>3) Low back pain intensity of > 3/10 Willing and able to receive study-related phone calls Exclusion Criteria: History of spine surgery at the level of the lumbar MBB Active worker's compensation or litigation claims New pain and/or psychiatric treatments within 2 weeks of enrollment Not fluent in English and/or not able to complete the questionnaires Any clinically unstable systemic illness that is judged to interfere with the study

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: Quantitative Sensory Testing
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Quantitative Sensory Testing<br>Participants with chronic low back pain and a scheduled lumbar medial branch block undergo quantitative sensory testing. | Behavioral: Cutaneous Probe<br>* A computer-controlled probe delivers temperatures to the skin to measure pain, offset analgesia and onset hyperalgesia.<br>Behavioral: Quantitative Sensory Testing<br>* Standard methods involving pinprick, pressure, heat, and cold applied to the skin are used to measure sensation and pain<br>Behavioral: Computer Tasks<br>* Quantitative Sensory Testing (QST) and computer tasks are used to measure changes in pain intensity.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Offset analgesia and onset hyperalgesia | Pain intensity difference during heat stimuli measured on a 0-100 sliding scale (0 is no pain, 100 is the most intense pain imaginable) at baseline | during this portion of the study visit (30 minutes) | 
| Low back pain intensity change | Patients respond to the question How would you rate your back pain right now? from 0 (no pain) to 10 (worst imaginable pain) to see how intense their back pain is each hour after the lumbar medial branch block. | Immediately after lumbar medial branch block and up to 16 hours after lumbar medial branch block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of low back pain | Participant self-reports the number of years they have experienced low back pain. The number of years for each participant will be reported. | Baseline | 
| PEG: A Three-Item Scale Assessing Pain Intensity and Interference | Assessment for self-reported average pain and pain interference within past 7 days. Responses range from 0 (no pain) to 10 (pain as bad as you can imagine). Total scores range from 0-30, and higher scores indicate more pain interference. | Baseline | 
| Baseline Back Pain Intensity | Assessment for determining how much a person hurts with a question ranked on a 11-point scale, from 0 = no pain to 10 = worst imaginable pain. The minimum raw summed score is 0 and the maximum score is 10. Lower raw response scores suggest lower pain intensity and better outcomes. | Baseline | 
| PROMIS Pain Interference 4a | Assessment for self-reported consequences of pain with 4 questions ranked on a 5-point scale, from not at all to very much. The minimum raw summed score is 4 and the maximum score is 20. Lower scores suggest better outcomes. | Baseline | 
| PROMIS Physical Function- 6b | Assessment for self-reported capability with 6 qualitatively scaled questions ranked on a 5-point scale, from without any difficulty to unable to do or not at all to cannot do. The minimum raw summed score is 6 and the maximum score is 30. | Baseline | 
| PROMIS Sleep Disturbance 6a | Assessment for self-reported perceptions of sleep quality and sleep depth with 6 questions ranked on a 5-point scale. The minimum raw summed score is 6 and the maximum score is 30. Lower scores suggest better outcomes. | Baseline | 
| 6-item Pain Catastrophizing Scale | Standardized survey score assessing pain perception before the study procedures begin. Rumination subscale score ranges from 0-16. Magnification subscale score ranges 0-12. Helplessness subscale score ranges from 0-24. Total score can be calculated by summing subscales. Total score ranges from 0-52, with higher scores indicating more pain catastrophizing. | Baseline | 
| Patient Health Questionnaire (PHQ-2) | The PHQ-2 inquires about the frequency of depressed mood and anhedonia over the past two weeks. The PHQ-2 includes the first two items of the PHQ-9. A PHQ-2 score ranges from 0-6. The authors identified a score of 3 as the optimal cutpoint when using the PHQ-2 to screen for depression. If the score is 3 or greater, major depressive disorder is likely. | Baseline | 
| PROMIS 4-item Depression | Assessment for self-reported negative mood and views of self with 4 questions ranked on a 5-point scale, from never to always. The minimum raw summed score is 4 and the maximum score is 20. Lower t-scores suggest better outcomes. | Baseline | 
| PROMIS 4-item Anxiety | Assessment for self-reported fear, anxious misery, hyperarousal, and somatic symptoms with 4 questions ranked on a 5-point scale, from never to always. The minimum raw summed score is 4 and the maximum score is 20. Lower scores suggest better outcomes. | Baseline | 
| Areas of Pain Body Map | The digital body figure contains 36 anterior regions and 38 posterior regions on which participants can mark areas in which they experience chronic pain. The number of pain areas each participant recorded will be reported, with a possibility of 74 total regions. | Baseline | 
| Treatment Expectancy | Assessment for the subject's expectations of treatment effec prior to lumbar medial branch block. Scores range from 0 (not at all) to 4 (very much), with total scores ranging from 0-24. Higher scores indicate higher expectations of the low back pain treatement. | Baseline | 
| Patient Global Impression of Change | The subject's impression of the impact of the lumbar medial branch block on their pain and function will be measured with a 7-item scale (1 = very much worse, 2 = much worse, 3 = minimally worse, 4 = no change, 5 = minimally improved, 6 = much improved, 7 = very much improved). | Immediately after lumbar medial branch block | 
| Situational pain catastrophizing scale (S-PCS) | Standardized survey score assessing pain perception immediately following the lumbar medial branch block. Scores range from 0-24, with higher scores representing more pain catastrophizing. | Immediately after lumbar medial branch block | 
| Pain intensity during QST | Changes in pain intensity during quantitative sensory tests measured on a 0-100 sliding scale (0 is no pain, 100 is the most intense pain imaginable) | during this portion of the study visit (60 minutes) | 
| Baseline back pain intensity | Patients respond to the question How would you rate your back pain on average? from 0 (no pain) to 10 (worst imaginable pain) to see how intense their back pain is before the lumbar medial branch block. | baseline | 
| Back pain intensity after lumbar medial branch block | Patients respond to the question How would you rate your back pain right now? from 0 (no pain) to 10 (worst imaginable pain) to see how intense their back pain is each hour after the lumbar medial branch block. | Immediately after lumbar medial branch block and up to 16 hours after lumbar medial branch block | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
lumbar, medial branch block, offset analgesia, onset hyperalgesia, QST, quantitative sensory testing