Quantitative multi-parameter assessment of age- and gender-related variation of back extensor muscles in healthy adults using Dixon MR imaging.

OBJECTIVES: Investigate sex differences in age-related back extensor muscle degeneration using Dixon MRI and analyze the relationship between quantitative muscle parameters and back muscle strength in healthy adults. METHODS: 105 healthy subjects underwent lumbar Dixon MRI. Fat fraction (FF), cross-sectional area (CSA), functional CSA (FCSA), and relative FCSA (RFCSA) of multifidus muscle (MF) and erector spinae (ES) were quantified. Back extension muscle strength was measured using an external fixation dynamometer. ANOVA with post hoc Tukey correction was used for age group comparisons. Partial and Spearman's correlation analyzed relationships between age, muscle parameters, and muscle strength. RESULTS: MF and ES FF significantly increased with age in both genders (r = 0.55-0.85; p < 0.001). Muscle FF increased prominently for females (40-49 years, MF and 50-59 years, ES) and males (60-73 years, MF and ES). In females, total ES FCSA and RFCSA (r = - 0.42, - 0.37; p < 0.01) correlated with age. While in males, all MF and ES muscle size parameters, except total MF CSA, correlated with age (r = - 0.30 to - 0.58; p < 0.05). Back extension muscle strength correlated with mean FF, total CSA, and total FCAS for MF and ES individually (p < 0.001). The combined MF + ES FCSA correlation coefficient (r = 0.63) was higher than FF (r = - 0.51) and CSA (r = 0.59) (p < 0.001). CONCLUSIONS: Age-related back extensor muscle degeneration varies by muscle type and sex. FCSA has the highest association with back muscle strength compared to FF and CSA. CLINICAL RELEVANCE STATEMENT: The investigation of sex differences in age-related back extensor muscle degeneration utilizing Dixon imaging may hold significant implications for evaluating spine health and enabling earlier intervention. Muscles' FCSA could contribute to acquiring additional evidence for reflecting muscle function change. KEY POINTS: • The multifidus muscle (MF) and erector spinae (ES) fat fraction (FF) increased with age at all lumbar disc levels in females and males. • Age-related changes in muscle morphological quantitative parameters of healthy adults were specific by muscle type and gender. • The muscle functional cross-sectional area (FCSA) measured by Dixon imaging may better monitor back extensor muscle strength changes than muscle FF and cross-sectional area (CSA).

An assessment of morphological and pathological changes in paravertebral muscle degeneration using imaging and histological analysis: a cross-sectional study.

BACKGROUND: The high signal of paravertebral muscle (PVM) on T2-weighted image (T2WI) is usually considered to be fatty degeneration. However, it is difficult to distinguish inflammatory edema from fatty degeneration on T2WI. The purpose of this study was to identify different types of PVM high signal in patients with low back pain (LBP) through magnetic resonance imaging (MRI) and histology. METHODS: Seventy patients with LBP underwent MRI. The signal change of multifidus both on T2WI and fat suppression image (FSI) was quantified by Image J. Furthermore, 25 of the 70 patients underwent surgery for degenerative lumbar disease and their multifidus were obtained during the operation. Histological analysis of the samples was performed by HE staining. RESULT: Three types of PVM signal changes were identified from the MRI. Type 1 (n = 36) indicated fatty degeneration characterized by a high signal on T2WI and low signal on FSI. High signal on both T2WI and FSI, signifying type 2 meant inflammatory edema (n = 9). Type 3 (n = 25) showed high signal on T2WI and partial signal suppression on FSI, which meant a combination of fatty degeneration and inflammatory edema. Histological results were consistent with MRI. Among the 25 patients who underwent surgery, type 1 (n = 14) showed adipocytes infiltration, type 2 (n = 3) showed inflammatory cells infiltration and type 3 (n = 8) showed adipocytes and inflammatory cells infiltration. CONCLUSION: From our results, there are three types of pathological changes in patients with PVM degeneration, which may help to decide on targeted treatments for LBP.

Quantitative assessment of erector spinae muscles and prognosis in elderly patients with pneumonia.

Erector spinae muscle (ESM) size has been reported as a predictor of prognosis in patients with some respiratory diseases. This study aimed to assess the association of ESM size on all-cause in-hospital mortality among elderly patients with pneumonia. We retrospectively included patients (age: ≥ 65 years) admitted to hospital from January 2015 to December 2017 for community-acquired pneumonia who underwent chest computed tomography (CT) on admission. The cross-sectional area of the ESM (ESMcsa) was measured on a single-slice CT image at the end of the 12th thoracic vertebra and adjusted by body surface area (BSA). Cox proportional hazards regression models were used to assess the influence of ESMcsa/BSA on in-hospital mortality. Among 736 patients who were admitted for pneumonia, 702 patients (95%) underwent chest CT. Of those, 689 patients (98%) for whom height and weight were measured to calculate BSA were included in this study. Patients in the non-survivor group were significantly older, had a greater frequency of respiratory failure, loss of consciousness, lower body mass index, hemoglobin, albumin, and ESMcsa/BSA. Multivariate analysis showed that a lower ESMcsa/BSA independently predicted in-hospital mortality after adjusting for these variables. In elderly patients with pneumonia, quantification of ESMcsa/BSA may be associated with in-hospital mortality.

The structural, functional and electrophysiological assessment of paraspinal musculature of patients with ankylosing spondylitis and non-radiographic axial spondyloarthropathy.

Paravertebral muscles are affected in spondyloarthritis. Decreased mobility of spine may lead to atrophy and fatty degeneration of these muscles. The objective of this study was to compare the sonographic, electrophysiological and magnetic resonance imaging (MRI) features of paraspinal muscles between patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). The patients who were diagnosed as AS with modified New York criteria and those as nr-axSpA with ASAS 2009 criteria were enrolled. Clinical evaluation, electrophysiological examination including nerve conduction studies and needle electromyography (EMG) for lower extremities and paraspinal mapping (PSM) were performed by the first examiner. The second examiner measured lumbar multifidus areas, graded the fatty degeneration of the muscle at different levels in T2 weighted axial MRI and also performed the ultrasonographic evaluation. A total of 19 patients with AS and 14 patients with nr-axSpA were evaluated. MRI of 2 patients with AS could not be obtained. Right lumbar multifidus area/vertebra area (MV ratio) was smaller in AS patients at L3 level (p 0,029); there were no significant differences in other levels. Fatty degeneration was also higher in AS patients in left multifidus at L5-S1 disc level (p 0,015). PSM scores that demonstrate the extent of denervation in paraspinal muscles were significantly higher in AS patients than in nr-axSpA patients (p < 0,001). Patients with AS have more fatty degeneration and denervation in paraspinal muscles. These processes may also contribute the severity of pain and disability. The relationship between paraspinal muscle denervation and progression of fatty degeneration should further be revealed.

Reliability of sonography in the assessment of lumbar stabilizer muscles size in healthy subjects and patients with scoliosis.

OBJECTIVE: The purpose of the present study was to compare the reliability of sonography in the evaluation of abdominal and multifidus muscles size between healthy subjects and patients with scoliosis. METHODS: In this study, 20 healthy males and 20 male patients with scoliosis (20-50 years old) were recruited. Multifidus and abdominal muscles (transversus abdominis, internal and external oblique) size were assessed by sonography. Three images were recorded; the first and second images were taken on the same day with an hour interval to evaluate within-day reliability, and the third image was taken one-week later to assess between-day reliability. RESULTS: Intraclass correlation coefficient (ICC = 0.82-0.91) demonstrated high within-day reliability of sonography in the assessment of abdominal muscle thickness in both groups. In addition, high between-day reliability was observed for these muscles in both healthy and patient groups (ICC = 0.80-0.89). Within-day and also between-day reliability of multifidus muscle were shown to be high in the healthy group (ICC = 0.81-0.88) and the patient group (ICC = 0.78-0.85). Overall, within-day reliability was higher than between-day reliability and also the reliability of sonography in healthy subjects was greater than of those suffering from scoliosis. CONCLUSIONS: According to the results, sonography was shown to be a highly reliable imaging technique for assessment of abdominal and multifidus muscle size in healthy males and those suffering from scoliosis.

A Comparison of the Abdominal and Lumbar Multifidus Muscle Size in Patients With Lumbar Spondylolisthesis and Healthy Patients at Rest and During Contraction Using Ultrasonography.

OBJECTIVE: Using ultrasonography, this study investigated the abdominal and lumbar multifidus muscle size in patients with lumbar spondylolisthesis compared with healthy patients at rest and during contraction. METHODS: This research was a nonexperimental, analytic case-control study. Ultrasound imaging was used to assess the thickness of the abdominal and lumbar multifidus muscles in 25 healthy patients and 25 patients with spondylolisthesis. For the purpose of this study, both men and women, aged 30 to 70 years, were recruited from physiotherapy clinics affiliated with the University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Measurements were taken at rest and during contraction. RESULTS: There was a significant difference in abdominal and lumbar multifidus muscle size between the healthy and spondylolisthesic groups, both at rest and contraction (P < .05 in all instances). No significant difference was found between the right and left for all measurements (P > .05). CONCLUSION: Patients with spondylolisthesis had smaller stabilizer muscle thickness at rest and during contraction compared with the healthy group.

Muscle Atrophy Measurement as Assessment Method for Low Back Pain Patients.

Low back pain is one of the most common pain disorders defined as pain, muscle tension, or stiffness localized below the costal margin and above the inferior gluteal folds, sometimes with accompanying leg pain. The meaning of the symptomatic atrophy of paraspinal muscles and some pelvic muscles has been proved. Nowadays, a need for new diagnostic tools for specific examination of low back pain patients is posited, and it has been proposed that magnetic resonance imaging assessment toward muscle atrophy may provide some additional information enabling the subclassification of that group of patients.

Assessment of the Cross-Sectional Areas of the Psoas Major and Multifidus Muscles in Patients With Adult Spinal Deformity: A Case-Control Study.

STUDY DESIGN: This is a case-control study. OBJECTIVE: The present study aimed to compare the cross-sectional areas of the psoas major and multifidus muscles between elderly patients with adult spinal deformity (ASD) and age-matched and body weight-matched controls, and to evaluate the associations between the cross-sectional areas of these muscles and the severity of spinal deformity. SUMMARY OF BACKGROUND DATA: The study included 49 female kyphosis patients with mild scoliosis (Cobb angle <20 degrees; mean age, 70.9 y, group D). The control group (group C) included age-matched and body weight-matched female patients who underwent abdominal surgery (n=98; mean age, 71.7 y). MATERIALS AND METHODS: The cross-sectional areas of the bilateral psoas majors and multifidus muscles were calculated using preoperative L4/L5 axial computed tomography images. In group D, the following spinopelvic parameters were assessed: sagittal vertical axis, pelvic tilt, pelvic incidence, lumbar lordosis, and thoracic kyphosis. The relationships between the muscle cross-sectional areas and spinopelvic parameters were evaluated. RESULTS: The cross-sectional area of the multifidus muscle was lower in group D than in group C. However, the cross-sectional area of the psoas major muscle was not different between the 2 groups. In multiple regression analysis, the cross-sectional area of the multifidus muscle was significantly associated with all spinopelvic parameters. CONCLUSIONS: The cross-sectional area of the multifidus muscle might be lower in elderly patients with ASD than in controls. In the elderly population, the severity of sagittal spinal deformity might be correlated with the cross-sectional area of the multifidus muscle. Therefore, muscle imbalances between the flexors and extensors of the spine could participate in the pathology of ASD.

MRI assessment of paraspinal muscles in patients with acute and chronic unilateral low back pain.

OBJECTIVE: To investigate the changes in paraspinal muscle cross-sectional area (CSA) and composition, using the digital data from lumbar spine MRIs of patients with acute and chronic low back pain (LBP). METHODS: In total, 178 patients with unilateral LBP who had lumbar MRI examination were recruited. The data were obtained by a retrospective documentation audit. The CSAs and mean signal intensities of the bilateral paraspinal muscles [psoas major (PM), quadratus lumborum, multifidus (MF) and erector spinae (ES)] were measured, and the percentage of fat infiltration was calculated. The data between the painful side and non-painful side were compared, and between-group comparisons were tested. 42 patients with chronic unilateral LBP could indicate the problem level, and the CSA and mean signal intensity of the MF muscle were analysed at the problem level, and one vertebral above and one vertebral level below the problem level. RESULTS: The CSAs of the PM and ES muscles were significantly decreased in the acute LBP group, while in the chronic LBP group, significant reduction in CSA was found in the MF and ES muscles on the painful side compared with the non-painful side. The mean signal intensity and fat content of the ES muscle on the painful side in the chronic LBP group was significantly higher than that on the painful side in the acute LBP group. The significant decrease of CSA in the MF muscle was found at multiple levels on the painful side. CONCLUSION: The present findings show that there is selective ipsilateral atrophy of paraspinal muscles, specific to the symptomatic side, in patients with acute and chronic LBP. The reduction of the muscle CSA and increased fatty infiltration occurred synchronously, and the extent of change is significantly greater in chronic LBP in the ES muscle. Atrophy of the MF muscle appears to be at multiple levels but side specific in relation to symptoms in patients with chronic LBP, and the decreased muscle CSA may occur prior to fatty infiltration. ADVANCES IN KNOWLEDGE: There are specific paraspinal muscles undergoing atrophy and fatty infiltration in patients with acute and chronic LBP on the symptomatic side. The CSA of the MF muscle decreased at multiple levels on the symptomatic side in patients with chronic unilateral LBP, which may occur prior to fatty infiltration.