# Mechanistic structure-function relationships for paraspinal muscle fat infiltration in chronic low back pain patients

> **NIH AR R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2026 · $337,535

## Abstract

PROJECT SUMMARY
Chronic low back pain (cLBP) is the world's leading debilitating condition and the most common reason for
opioid prescription in the US. While axial cLBP is commonly considered non-specific and multifactorial, it is
often suspected a dysfunction of the spinal stabilization system that includes the intervertebral disc (IVD) and
adjacent paraspinal muscles (PSMs). Axial cLBP is notoriously challenging to treat because of uncertainty
about patient-specific causal mechanisms preventing effective matching to treatments. IVD degeneration is
easily appreciated with clinical imaging and often studied. Less is known about the role of PSM degeneration,
including atrophy and fat infiltration (FI), which are assumed to relate to cLBP, although existing evidence does
not provide a clear association. Given the availability of advanced MRI sequences that quantify FI, it is now
possible to investigate PSM FI patterns that will inform how it may relate to functional outcomes in cLBP
patients.
 The current working hypothesis is that degenerative IVD pathology promotes PSM FI as a result of a
compensatory biomechanical response of the muscle in an attempt to stabilize an affected spinal segment that
overtime leads to neuromuscular fatigue and/or from direct exposure to pro-inflammatory factors from IVD
damage. We hypothesize that PSM FI spatial distribution patterns (fat maps) have significant correlation with 1)
patient-specific kinematics and PSM activation patterns (i.e. motor control), and 2) bimolecular factors, derived
from patient PSM muscle biopsy. To test this hypothesis, we will quantify PSM FI, degenerative IVD pathology,
trunk and full-body kinematics, and paraspinal muscle activation in 40 axial cLBP subjects and 40 age-matched
controls. We will also collect a muscle tissue sample from the cLBP patients to uncover the biomolecular
mechanisms of PSM FI. In this study, we are proposing to 1) quantify spatial distribution of paraspinal muscle
fat infiltration

## Key facts

- **NIH application ID:** 11306684
- **Project number:** 5R01AR081324-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Jeannie Fern Bailey
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** AR
- **Fiscal year:** 2026
- **Award amount:** $337,535
- **Award type:** 5
- **Project period:** 2023-06-01T00:00:00 → 2028-03-31T00:00:00

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11306684

## Citation

> US National Institutes of Health, RePORTER application 11306684, Mechanistic structure-function relationships for paraspinal muscle fat infiltration in chronic low back pain patients (5R01AR081324-04). Retrieved via AI Analytics 2026-06-26 from https://api.ai-analytics.org/grant/nih/11306684. Licensed CC0.

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