Evidence map›Paper›PMID 40623529›Full record

Observational studyThe spine journal : official journal of the North American Spine Society2026

Spatial patterns of fat within the deep multifidus as a biomarker for chronic low back pain.

Karim Khattab, Lucas K Dziesinski, Jessica Ornowski, Jiamin Zhou, Noah B Bonnheim, Rebecca Crawford, Aaron Scheffler, Aaron J Fields, Conor W O'Neill, Jeffrey C Lotz and 2 more

Abstract readObservational Study
In one paragraph

Observational study in The spine journal : official journal of the North American Spine Society, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed.

  1. Article
  2. Article
  3. Chronicity and physical activity levels independently associate with spatial patterns of multifidus fat infiltration in chronic low back pain patients.European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2026
    Article
  4. Article
  5. Article
  6. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Karim KhattabDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Lucas K DziesinskiDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Jessica OrnowskiDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Jiamin ZhouDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Noah B BonnheimDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Rebecca CrawfordEugalyptus GmbH, Baar, Switzerland.
Aaron SchefflerDepartment of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
Aaron J FieldsDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Conor W O'NeillDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Jeffrey C LotzDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA.
Jeannie F BaileyDepartment of Orthopedic Surgery, University of California, San Francisco, CA, USA. Electronic address: jeannie.bailey@ucsf.edu.
REACH Investigators

Funding

UCSF Core Center for Patient-centric Mechanistic Phenotyping in Chronic Low Back PainU19AR076737 · NIAMS · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · PI KRUG, ROLAND · 2019 to 2023
$34.1M
Skeletal Biology and Biomechanics (SBB) CoreP30AR075055 · NIAMS · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · PI Wenhan Chang · 2019 to 2026
$7.1M
Mechanistic structure-function relationships for paraspinal muscle fat infiltration in chronic low back pain patientsR01AR081324 · NIAMS · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · PI Jeannie Fern Bailey · 2023 to 2026
$1.4M
NIAMS NIH HHS P30 AR075055NIAMS NIH HHS R01 AR081324NIAMS NIH HHS U19 AR076737
6 · The paper itself

Abstract

background contextChronic low back pain (cLBP) patients often have elevated fat infiltration (FI) in the multifidus (MF), but it is unclear how this relates to pain and degenerative spine features. Most prior work assess MF degeneration as the average whole-muscle fat content even though deep and superficial fascicles of the MF have different structural and functional characteristics. Assessing the spatial distribution of MF FI may provide regional context for causal mechanisms which may have distinct regional presentations within the muscle. PURPOSE: This study assesses spatial patterns of MF FI at each lumbar level to identify regional differences associated with cLBP symptoms and degenerative spine features. STUDY

designThis is an observational cross-sectional study. PATIENT SAMPLE: Our study sample consisted of 230 cLBP patients from the BACPAC comeback cohort who reported low back pain that has persisted for the past 3 months. OUTCOME MEASURES: Measures included MF fat-maps-a FI curve showing the spatial distribution of fat moving radially through the MF-created at each lumbar level (L1L2-L5S1). Other measures included average fat fraction in the deepest 15% of the MF (deep15 FI%), average whole-muscle fat fraction (overall FI%) and the Pain, Enjoyment of Life, and General Activity (PEG) survey score.

methodsWe collected 3T MRI and used advanced sequences (IDEAL) to map the spatial distribution of MF FI at each lumbar level. We used statistical parametric mapping to identify spatial patterns of fat in the MF associated with age, sex, and BMI. Then, we tested for differences in spatial patterns of MF FI associated with pain and adjacent disc degeneration. Next, we calculated the fat fraction in a region of interest in the deepest 15% of the MF (deep15 FI%) and used linear mixed effects modeling to compare how age, sex, BMI, pain, and degenerative spine features associate with the deep15 FI% and the overall FI% separately. Lastly, we used linear regression models of PEG to compare FI measures as predictors for pain.

resultsElevated FI associated with PEG and adjacent disc degeneration only within the deepest 10% (p<.05) and deepest 25% (p<.01) of the MF respectively at the lower lumbar levels. Associations between demographic factors and FI were not specific to the deep MF. Older age and female sex associated with elevated FI throughout the muscle (p<.001) while higher BMI associated with elevated FI in only the superficial 60% of the MF (p<.001). Lastly, higher mean deep15 FI% but not mean overall FI% at the lower lumbar levels associated with higher PEG (p=.023).

conclusionsFI in deep regions of the MF at L4L5 and L5S1 is more strongly associated with pain and adjacent disc degeneration and less associated with age, sex, and BMI than overall FI%. We identify regional differences in MF FI related to pain which improves our understanding of cLBP-related MF degeneration and provides additional context for possible causal mechanisms of FI. Further, the "deep15" FI% is a novel MF FI measure, and possible biomarker, more strongly associated with cLBP than summary measures.

Indexed as

Adipose TissueChronic PainLow Back PainParaspinal MusclesAdultAgedBiomarkersCross-Sectional StudiesFemaleHumansLumbar VertebraeMagnetic Resonance ImagingMaleMiddle AgedBiomarkersBiomarkerChronic low back painFat infiltrationMultifidusMuscle qualitySpatial distribution

Identifiers

PMID40623529
PMCPMC12445350

What OpenQuestion holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.