New Predictive Index for Lumbar Paraspinal Muscle Degeneration Associated With Aging.
METHODS
A cross-sectional imaging study of paraspinal muscle degeneration using a new index for easy evaluation.


OBJECTIVE
To examine the natural progression of age-related changes in the lumbar paraspinal muscles and to verify the validity of our new index for evaluating paraspinal muscle degenerationSUMMARY OF BACKGROUND DATA.: Measurement of paraspinal muscle morphology is an effective method for reflecting atrophy and fat infiltration, but it is complicated to perform. Therefore, we focused on the groove between lumbar paraspinal muscles as a simple index for evaluating paraspinal muscle degeneration.


METHODS
A total of 160 subjects aged 10 to 88 years (10 male and 10 female subjects in each decade) with lumbar lordosis of more than 20° were included. Body mass index (BMI) was calculated. Sagittal T2-weighted magnetic resonance imaging (MRI) was used to measure lumbar lordosis, while axial T2-weighted MRI was used to measure cross-sectional area (CSA) and fat infiltration rate of the paraspinal muscles at the intervertebral disc level from L1 to L5. To quantify the depth of the groove between the paraspinal muscles, our own image index (lumbar indentation value (LIV): equal to the length of the bulge of the muscle to the attachment of the spinous process), also was measured. We then determined the correlation between LIV and paraspinal muscle degeneration.


RESULTS
There were no significant differences in BMI and lumbar lordosis between age groups. CSA of the paraspinal muscles tended to decrease with age, and fat infiltration rate increased with age. There was a negative correlation between CSA and fat infiltration rate at all levels (r = -0.474 to -0.634). LIV decreased significantly with age and strongly correlated with CSA at all levels (r = 0.709-0.789).


CONCLUSIONS
Our new index is a simple and effective parameter for evaluating paraspinal muscle degeneration associated with aging.


METHODS
4.
*Department of Orthopaedic Surgery, Seikeikai Hospital, Osaka, Japan†Department of Orthopaedic Surgery, Saiseikai Nakatsu Hospital, Osaka, Japan‡Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
Kazushi
K
Takayama
Teruo
T
Kita
Hiroaki
H
Nakamura
Fumiaki
F
Kanematsu
Toshiya
T
Yasunami
Hideki
H
Sakanaka
Yoshiki
Y
Yamano
D000273:Adipose Tissue / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D015992:Body Mass Index; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D008141:Lordosis / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064170:Paraspinal Muscles / Q000473:pathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055948:Sarcopenia / Q000473:pathology*; D012720:Severity of Illness Index; D055815:Young Adult