We quantified fatty infiltration (FI) geography of the lumbar spine to identify whether demographics, temporal low back pain (LBP), and disability influence FI patterns.
Lumbar paravertebral muscle FI has been associated with age, sex, LBP, and disability; yet, FI accumulation patterns are inadequately described to optimize interventions.
This cross-sectional study employed lumbar axial T1-weighted magnetic resonance imaging in 107 Southern-Chinese adults (54 females, 53 males). Single-slices at the vertebral inferior end-plate per lumbar level were measured for quartiled-FI, and analyzed against demographics, LBP, and disability (Oswestry Disability Index).
Mean FI% was higher in females, on the right, increased per level caudally, and from medial to lateral in men (P < 0.05). FI linearly increased with age for both sexes (P < 0.01) and was notably higher at L 4&5 than L1, 2&3 for cases aged 40 to 65 years. BMI and FI were unrelated in females and inversely in males (P < 0.001). Females with LBPweek and males with LBPyear had 1.7% (each) less average FI (P < 0.05) than those without pain at that time-point. Men locating their LBP in the back had less FI than those without pain (P < 0.001). Disability was unrelated to FI for both sexes (P > 0.05).
Lumbar paravertebral muscle FI predominates in the lower lumbar spine, notably for those aged 40 to 65, and depends more on sagittal than transverse distribution. Higher FI in females and differences of mean FI between sexes for BMI, LBP, and disabling Oswestry Disability Index suggest sex-differential accumulation patterns. Our study contradicts pain models rationalizing lumbar muscle FI and may reflect a normative sex-dependent feature of the natural history of lumbar paravertebral muscles.
Level of Evidence: 2
This is the first study to quantify the geography of lumbar paravertebral muscle fat infiltration (FI) in the transverse plane based on axial MRI. Although paravertebral FI increased with age, sex-differential fat accumulation patterns were noted, with variations with body mass index (BMI), low back pain (LBP), and disability profiles between males and females.
∗Body Urbanist, Rotterdam, The Netherlands
†Institute for Health Sciences, Zürich University of Applied Sciences, Winterthur, Switzerland
‡Physio + Co GmbH, Zurich, Switzerland
§Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulum, Hong Kong, SAR China
¶Northern Sydney Local Health District and Faculty of Health Sciences, The University of Sydney, St. Leonards, Australia
||Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL
∗∗School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia
††Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL
‡‡International Spine Research and Innovation Initiative (ISRII), RUSH University Medical Center, Chicago, IL.
Address correspondence and reprint requests to Dino Samartzis, DSc, Department of Orthopaedic Surgery, RUSH University Medical Center, 1611 W. Harrison Street, Chicago, IL 60612; E-mail: firstname.lastname@example.org
Received 29 November, 2018
Revised 20 February, 2019
Accepted 14 March, 2019
The manuscript submitted does not contain information about medical device(s)/drug(s).
Hong Kong Research Grants Council funds were received in support of this work.
No relevant financial activities outside the submitted work.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.spinejournal.com).