Is Conditioned Pain Modulation Predictive of Clinical Improvement in Patients With Chronic Low Back Pain?

Conditioned pain modulation (CPM) a measure of the effectiveness of the descending pain pathway and therefore a measure of the body's ability to perform endogenous analgesia. In subjects with normal function of the descending pain pathway, the net-effect during CPM testing is anti-nociceptive, or inhibition of the ascending pain pathway. In those with impaired descending pain pathway function, the response to CPM testing is pro-nociceptive, indicating that the body is unable to inhibit the pain signal, or may even amplify it. There is literature that supports the presence of impaired CPM, and therefore impaired descending pain pathway function, in numerus chronic pain conditions, including low back pain. Impaired descending pain pathway function may be contributing to this chronic pain presentation. This study will give us information on whether a typical physical therapy plan of care is able to improve impaired CPM, and if CPM values are predictive of improvement in physical therapy.

Study Overview

• Status: Recruiting
• Conditions: Low Back Pain
• Intervention / Treatment: Other: Physical therapy

• Study Type: Interventional
• Enrollment (Estimated): 57
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kyle R Petrey, DPT; Phone Number: 8472742794; Email: kyle.r.petrey.mil@health.mil

Study Locations

• United States
  • Texas
    • Ft Sam Houston, Texas, United States, 78234
      • Recruiting
      • Brooke Army Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• DEERS eligible
• English speaking
• Age 18-64 years
• ODI baseline ≥25%
• NPRS baseline ≥3/10
• Low back pain symptoms greater than 3 months
• Must be able to commit to at least six weeks of physical therapy interventions

Exclusion Criteria:

• Serious spinal pathology (acute fracture, active cancer, inflammation, inflammatory arthropathy)
• Low back pain symptoms radiating below the knee
• Pregnancy
• Diagnosed neurological disease including traumatic brain injury, multiple sclerosis, chronic regional pain syndrome, and fibromyalgia.
• History spinal surgery
• Currently under litigation related to low back pain
• Currently going through Medical Evaluation Board (MEB)
• Retiring or separating from the military within a year

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: chronic low back pain; Age 18-64 years with low back pain duration greater than 3 months.	Other: Physical therapy; The intervention will be physical therapy standard of care.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Oswestry Disability Index	The ODI will be the primary outcome for this study. The ODI contains 10 items that assess function and disability (0 = no disability, 100 = maximal disability).	From enrollment until end of study at 6 weeks.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central Sensitization Inventory	The CSI is a 25-item questionnaire that assesses symptoms common to central sensitization syndromes using a 0-100-point scale, in which 100 indicates a higher level of symptoms common to central sensitization.	From enrollment until study end at 6 weeks.
Conditioned pain modulation	CPM calculation: It is recommended that CPM response be reported as an absolute value and percent change. The calculation for absolute value is: CPM = PPTpre -PPTconditioning. PPTpre is the testing stimulus conducted before conditioning stimulus application and PPTconditioning is the testing stimulus conducted during conditioning stimulation. This is expressed in kPa. A negative value suggests that CPM is functioning effectively and indicative of an anti-nociceptive profile, while a positive value suggests CPM is impaired and indicative of a pro-nociceptive profile. The second method will be CPM expressed as percent change of the testing stimulus before and during the application of the conditioning stimulus. The equation for percent change is: [(postPPT - prePPT)/prePPT] * 100. CPM will be expressed as continuous ratio data via absolute value and percent change. The absolute value score will be used for the statistical model and will be collected at baseline and follow up.	From enrollment until study end at 6 weeks.
Temporal Summation	Temporal summation is calculated as follows: VAS10th - VAS1st. A positive number indicates the magnitude of temporal summation of pain. This will be expressed as continuous ratio data and will be collected at baseline and follow up.	From enrollment until study end at 6 weeks.
Numeric pain rating scale	The NPRS is an 11-point numerical pain rating scale used to measure pain. Patients rate pain ranging between 0 (no pain) and 10 (worst pain imaginable). This will be measured as the mean of three pain ratings: best pain rating over 24 hours, worst pain rating over 24 hours, and current pain rating.	From enrollment until study end (6 weeks).
Global rating of change scale	The GRC utilized in this study is an 11-point scale designed to quantify a patient's improvement or deterioration over time. The GRC will only be completed at discharge (6-weeks).	From enrollment until end of study (6 weeks)

Collaborators and Investigators

• Sponsor: Brooke Army Medical Center
• Investigators: Principal Investigator: Kyle Petrey, DPT, BAMC

Study record dates

Study Major Dates

• Study Start (Actual): September 19, 2024
• Primary Completion (Estimated): July 1, 2025
• Study Completion (Estimated): July 1, 2025

Study Registration Dates

• First Submitted: August 6, 2024
• First Submitted That Met QC Criteria: August 6, 2024
• First Posted (Actual): August 9, 2024

Study Record Updates

• Last Update Posted (Actual): April 23, 2025
• Last Update Submitted That Met QC Criteria: April 22, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: low back pain; physical therapy; conditioned pain modulation; temporal summation
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Back Pain; Low Back Pain
• Other Study ID Numbers: C.2024.070

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Requests for deidentified data will be considered on a case by case basis.
• IPD Sharing Time Frame: Requests for deidentified data will be considered on a case by case basis.
• IPD Sharing Access Criteria: Requests for deidentified data will be considered on a case by case basis.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No