Long-term lumbar multifidus muscle atrophy changes documented with magnetic resonance imaging: a case series

Correlation between severity of spinal stenosis and multifidus atrophy in degenerative lumbar spinal stenosis

BACKGROUND

Degenerative lumbar spinal stenosis (DLSS) is a common degenerative condition in older adults. Muscle atrophy (MA) is a leading cause of muscle weakness and disability commonly reported in individuals with spinal stenosis. The purpose of this study was to investigate if the MA correlates with the grade of spinal stenosis in patients with DLSS.

METHODS

A retrospective analysis on 48 male and 184 female DLSS patients aged around 54.04 years (54.04 ± 8.93) were involved and divided into 6 groups according to claudication-distance-based grading of spinal stenosis, which confirmed by two independent orthopedic surgeons using T2- weighted images. Using 1.5T MRI scanner, the severity of MA is assessed based on its negative correlation with the ratio of total fat-free multifidus muscle cross-sectional area (TFCSA) to total multifidus muscle cross-sectional area (TCSA). Adobe Photoshop CS6 was used for qualitative image analysis and calculate the TFCSA/TCSA ratio to assess the severity of MA, compare the grade of MA with the spinal stenosis segment, stenosis grade and symptom side.

RESULTS

In DLSS group, The TFCSA/TCSA ratio are 74.33 ± 2.18 in L3/4 stenosis, 75.51 ± 2.79 in L4/5 stenosis, and 75.49 ± 2.69 in L5/S1 stenosis. there were significant decreases in the TFCSA/TCSA ratio of stenotic segments compared with non-stenotic segments of the spinal canal (P < 0.05) while no significant difference between the non-stenotic segments (P > 0.05). TFCSA/TCSA ratios is significant differences in the TFCSA/TCSA ratios of the 6 DLSS groups (F = 67.832; P < 0.05). From Group 1 to Group 6, the TFCSA/TCSA ratio of stenotic segments positively correlated with the absolute claudication distance (ACD). (P < 0.001, r = 0.852). Besides, the TFCSA/TCSA ratios are smaller in the symptomatic sides of the spine than the contralateral sides (t = 4.128, P = 0.001).

CONCLUSIONS

The stenotic segments of the spinal canal are more atrophied than the non-stenotic segment in DLSS patients. It is shows that a strong positive correlation between the severity of multifidus atrophy and the severity of spinal stenosis.

Research Progress on the Mechanism of Lumbarmultifidus Injury and Degeneration

This review summarizes recent research progress in the clinical features, image manifestations, and pathological mechanism of multifidus injury. After a brief introduction to the fiber classification, innervation, blood supply, and multifidus function, some factors of multifidus injury, consisting of denervation, intraoperative incision selection and traction, and lumbar degenerative disease are overviewed. In addition, the clinical index of multifidus injury including myoglobin, creatine kinase, IL-6, C-reactive protein, the cross-sectional area of multifidus, the degree of fat infiltration, and intraoperative biopsy are summarized. Furthermore, we recommend that patients with chronic low back pain should take the long-term exercise of lumbodorsal muscles. Finally, some remaining issues, including external fixation and the imaging quantitative evaluation criteria of multifidus, need to be further explored in the future.

Is there a correlation between upper lumbar disc herniation and multifidus muscle degeneration? A retrospective study of MRI morphology

Background

The purpose of the study is to investigate the correlation between upper lumbar disc herniation (ULDH) and multifidus muscle degeneration via the comparison of width, the cross-sectional area and degree of fatty infiltration of the lumbar multifidus muscle.

Methods

Using the axial T2-weighted images of magnetic resonance imaging as an assessment tool, we retrospectively investigated 132 patients with ULDH and 132 healthy individuals. The total muscle cross-sectional area (TMCSA) and the pure muscle cross-sectional area (PMCSA) of the multifidus muscle at the L1/2, L2/3, and L3/4 intervertebral disc levels were measured respectively, and in the meantime, the average multifidus muscle width (AMMW) and degree of fatty infiltration of bilateral multifidus muscle were evaluated. The resulting data were analyzed to determine the presence/absence of statistical significance between the study and control groups. Multivariate logistical regression analyses were used to evaluate the correlation between ULDH and multifidus degeneration.

Results

The results of the analysis of the two groups showed that there were statistically significant differences (p < 0.05) between TMCSA, PMCSA, AMMW and degree of fatty infiltration. The multivariate logistic regression analysis indicated that the TMCSA, PMCSA, AMMW and the degree of fatty infiltration of multifidus muscle were correlated with ULDH, and the differences were statistically significant (P < 0.05).

Conclusions

A correlation could exist between multifidus muscles degeneration and ULDH, that may be a process of mutual influence and interaction. Lumbar muscle strengthening training could prevent and improve muscle atrophy and degeneration.

How to balance the treatment of stress urinary incontinence among female athletes?

Urinary incontinence in the general population occurs in 7% of non-pregnant women under 39 years old, 17% of those 40 to 59 years old, and 23-32% of those over 60 years old. In athletes the prevalence is higher, especially in high-impact training and gravity sports. Pelvic floor muscles (PFM) have two important roles; they serve as the support for abdominal organs and are crucial for closure of the urethra, vagina and rectum. We present the proper mechanisms of PFM caudal contractions with proper abdominal muscle control to avoid excessive intra-abdominal pressure. Pelvic floor sonography is discussed as the only objective method for pelvic floor examination among sportswomen and a tool which should be used routinely by urophysiotherapists and urogynecologists. A multidisciplinary individualized approach to stress urinary incontinence among athletes is presented including: physiotherapy, diagnostic imaging, use of a pessary, tampons, pharmacologic and surgical treatment. We present guidelines for stress urinary incontinence treatment in sportswomen of different age.

Which is the most affected muscle in lumbar back pain - multifidus or erector spinae?

Purpose

The purpose of this study is to evaluate the relationship between lumbar back pain, lumbar disc herniation, and erector spinae and multifidus muscle lipomatous degeneration.

Material and methods

After receiving approval from the clinical studies Ethics Committee, magnetic resonance imaging (MRI) studies of patients who had physical examination in orthopaedic, neurology, neurosurgery, physical medicine and rehabilitation clinics were evaluated. Their pre-diagnoses were ‘herniated nucleus pulposus’ or ‘lumbar disc herniation’ or ‘back pain’ and their age range was between 18 and 64 years. Patients who had vertebral fracture, spondylitis-spondylodiscitis, tumours, structural anomalies such as spondylolisthesis, scoliosis and vertebral segmentation anomalies and previous surgery in the lumbar area were excluded. There were 205 patients in the case group who had lumbar disc herniation between L1-S1 level and there were 187 patients in the control group who had no lumbar disc herniation. In the study, patient age, sex, herniation level and erector spinae and multifidus muscle lipomatous degeneration were compared. Muscle lipomatous degeneration were evaluated with a visual scale.

Results

There were 105 men and 100 women in the case group and 88 men and 99 women in the control group. In the case group, lumbar disc herniation was detected mostly at L4-5 and L5-S1 levels. There was no significant difference between case and control groups with regard to erector spinae and multifidus muscle lipomatous degeneration. In the case group, lipomatous degeneration of the erector spinae was higher compared to that of the multifidus muscle.

Conclusions

Patients with low back pain may have fatty degeneration in erector spina and multifidus muscles with or without LDH, but LDH accelerates this process rather than being a result of it. In patients with LDH, fatty degeneration in the erector spina is more pronounced than in multifidus, and the erector spina is more affected by the LDH process.

Inconsistent descriptions of lumbar multifidus morphology: A scoping review

Background

Lumbar multifidus (LM) is regarded as the major stabilizing muscle of the spine. The effects of exercise therapy in low back pain (LBP) are attributed to this muscle. A current literature review is warranted, however, given the complexity of LM morphology and the inconsistency of anatomical descriptions in the literature.

Methods

Scoping review of studies on LM morphology including major anatomy atlases. All relevant studies were searched in PubMed (Medline) and EMBASE until June 2019. Anatomy atlases were retrieved from multiple university libraries and online. All studies and atlases were screened for the following LM parameters: location, imaging methods, spine levels, muscle trajectory, muscle thickness, cross-sectional area, and diameter. The quality of the studies and atlases was also assessed using a five-item evaluation system.

Results

In all, 303 studies and 19 anatomy atlases were included in this review. In most studies, LM morphology was determined by MRI, ultrasound imaging, or drawings – particularly for levels L4–S1. In 153 studies, LM is described as a superficial muscle only, in 72 studies as a deep muscle only, and in 35 studies as both superficial and deep. Anatomy atlases predominantly depict LM as a deep muscle covered by the erector spinae and thoracolumbar fascia. About 42% of the studies had high quality scores, with 39% having moderate scores and 19% having low scores. The quality of figures in anatomy atlases was ranked as high in one atlas, moderate in 15 atlases, and low in 3 atlases.

Discussion

Anatomical studies of LM exhibit inconsistent findings, describing its location as superficial (50%), deep (25%), or both (12%). This is in sharp contrast to anatomy atlases, which depict LM predominantly as deep muscle. Within the limitations of the self-developed quality-assessment tool, high-quality scores were identified in a majority of studies (42%), but in only one anatomy atlas.

Conclusions

We identified a lack of standardization in the depiction and description of LM morphology. This could affect the precise understanding of its role in background and therapy in LBP patients. Standardization of research methodology on LM morphology is recommended. Anatomy atlases should be updated on LM morphology.

Correlation between multifidus fatty atrophy and lumbar disc degeneration in low back pain

Background

Chronic low back pain (LBP) is common and associated with lumbar disc herniation. The purpose of this study was to investigate if the grade of lumbar disc degeneration correlates with the degree of lumbar multifidus muscle (LMM) fatty atrophy.

Methods

A retrospective analysis on 16 males and 19 females with chronic LBP and a mean age of 47.2 years. Using MRI, the grade of lumbar intervertebral discs degeneration was assessed according to the Pfirrmann classification at L4/L5 and L5/S1 levels. Fatty infiltration of the LMM was graded as normal, mild, moderate and severe. Adobe Photoshop CS6 was used for qualitative image analysis by measuring the Cross-sectional area (CSA) of the pure fat component of LMM.

Results

There was a low correlation (R = 0.37) and significant association (ANOVA, p = 0.001, 95% CI 2.07–8.14) between the grade of lumbar disc degeneration and the degree of LMM fatty atrophy. Mean value of intervertebral disc degeneration was 2.9 for the L4/L5 level and 3.2 for L5/S1 respectively. The percentage of fat infiltration of the LMM at both studied levels showed a mean value of 22.91+/− 13.19% for L4/L5 and a higher mean value of 26.37+/− 12.89% for L5/S1. There were higher fatty atrophy scores in women and more disc degeneration in men.

Conclusion

The percentage of LMM atrophy is higher in the lower levels (L5/S1) and shows a low correlation with the grade of disc degeneration.

The effect of high-intensity resistance exercise on lumbar musculature in patients with low back pain: a preliminary study

Background

Muscle atrophy and fatty infiltration of the lumbar extensors is associated with LBP. Exercise-based rehabilitation targets strengthening these muscles, but few studies show consistent changes in muscle quality with standard-of-care rehabilitation. The goal of this study was to assess the effect of high-intensity resistance exercise on lumbar extensor muscle size (cross sectional area) and quality (fat fraction) in individuals with low back pain (LBP).

Methods

Fourteen patients with LBP were recruited from a local rehabilitation clinic. Patients underwent MRI scanning before and after a standardized 10-week high-intensity machine-based, resistance exercise program. Patient pain, disability, anxiety/depression, satisfaction, strength, and range of motion was compared pre- and post-rehabilitation using analysis of covariance (covariates: age, gender). Exercise-induced changes in MRI, and patient functional outcome measures were correlated using Pearson’s correlation test.

Results

No significant differences were found in muscle size or fatty infiltration of the lumbar extensors over the course of rehabilitation (p > 0.31). However, patients reported reduced pain (p = 0.002) and were stronger (p = 0.03) at the conclusion of the program. Improvements in muscle size and quality for both multifidus and erector spinae correlated with improvements in disability, anxiety/depression, and strength.

Conclusion

While average muscle size and fatty infiltration levels did not change with high-intensity exercise, the results suggest that a subgroup of patients who demonstrate improvements in muscle health demonstrate the largest functional improvements. Future research is needed to identify which patients are most likely to respond to this type of treatment.

Age and sex-based distribution of lumbar multifidus muscle atrophy and coexistence of disc hernia: an MRI study of 2028 patients

PURPOSE

We aimed to investigate the prevalence of lumbar multifidus muscle (LMM) atrophy in patients having mechanical low back pain with and without disc hernia.

METHODS

In total, 2028 lumbar magnetic resonance imaging scans of low back pain patients (age range, 18-88 years) were re-evaluated retrospectively. LMM atrophy was visually assessed in axial sections of L4-L5 and L5-S1 levels.

RESULTS

LMM atrophy prevalence at both levels was significantly higher in subjects ≥40 years compared with younger adults (P < 0.001). LMM atrophy was significantly more frequent in women than in men (P < 0.001). Among patients with low back pain without hernia, LMM atrophy was significantly more frequent than normal muscle (n=559 vs. n=392; P < 0.001). Frequency of LMM atrophy in low back pain patients without disc hernia was 13%. Hernia was more frequent in patients with LMM atrophy compared with patients without atrophy (P < 0.001).

CONCLUSION

LMM atrophy is more common in women; its prevalence and severity are observed to increase with advancing age, and disc hernia is found more frequently in individuals with LMM atrophy.

Trunk Muscle Characteristics of the Multifidi, Erector Spinae, Psoas, and Quadratus Lumborum in Older Adults With and Without Chronic Low Back Pain

Study Design Cross-sectional study. Objective To determine whether there are differences in trunk muscle characteristics between older adults with and without chronic low back pain (LBP), while controlling for age, sex, and body mass index. Background Muscle support for the trunk is provided by the multifidi, erector spinae, psoas, and quadratus lumborum. Trunk muscle characteristics may be altered with aging and/or chronic LBP. To date, most trunk muscle research has been conducted among younger adults. Given age-related muscle changes, such as reduced size and increased intramuscular fat, studies are needed in older adults, including those comparing older adults with and without LBP. Methods One hundred two older adults with (n = 53) and without (n = 49) chronic LBP were included. Cross-sectional area (CSA) measurements were taken by tracing inside the fascial borders on magnetic resonance images. Pixel intensity summaries were obtained to compute muscle-to-fat indices and relative muscle CSA, that is, CSA void of fat. Right/left averages for levels L2 through L5 were determined. Mixed-design analyses of covariance were used to test for differences between groups, based on LBP presence and sex, across levels (P≤.05). Results Older adults with LBP had a greater average multifidus muscle-to-fat index (0.51 versus 0.49) and smaller average erector spinae relative muscle CSA (8.56 cm² versus 9.26 cm²) when compared to control participants without LBP. No interactions between LBP status and average muscle characteristics were found for the psoas or quadratus lumborum (P>.05). Conclusion Up to 54% of older adult trunk muscle CSA may be fat. Women have smaller muscles and greater intramuscular fat (at lower spinal levels) than men. J Orthop Sports Phys Ther 2017;47(3):173-179. Epub 3 Feb 2017. doi:10.2519/jospt.2017.7002.

Multifidi Muscle Characteristics and Physical Function Among Older Adults With and Without Chronic Low Back Pain

OBJECTIVE

To determine whether multifidi size, intramuscular fat, or both, are associated with self-reported and performance-based physical function in older adults with and without chronic low back pain (LBP).

DESIGN

Case-control study.

SETTING

Individuals participated in a standardized evaluation in a clinical laboratory and underwent magnetic resonance imaging (MRI) of the lumbar spine at a nearby facility.

PARTICIPANTS

A volunteer sample of community-dwelling older adults (N=106), aged 60 to 85 years, with (n=57) and without (n=49) chronic LBP were included in this secondary data analysis.

INTERVENTION

Average right-left L5 multifidi relative (ie, total) cross-sectional area (CSA), muscle-fat infiltration index (MFI) (ie, a measure of intramuscular fat), and relative muscle CSA (rmCSA) (ie, total CSA minus intramuscular fat CSA) were determined from MRIs. Linear regression modeling was performed with physical function measures as the dependent variables. Age, sex, and body mass index were entered as covariates. The main effects of L5 multifidi MFI and rmCSA, as well as their interaction with group assignment, were compared as independent variables.

MAIN OUTCOME MEASURES

Medical Outcomes Study 36-Item Short-Form Health Survey physical functioning subscale, timed Up and Go, gait speed, and fast stair descent performance.

RESULTS

Interaction terms between L5 multifidi MFI and group assignment were found to be significant contributors to the variance explained in all physical function measures (P≤.012). Neither the main effect nor the interaction with group assignment for L5 multifidi rmCSA significantly contributed to the variance explained in any of the physical function measures (P>.012).

CONCLUSIONS

Among older adults with chronic LBP of at least moderate intensity, L5 multifidi muscle composition, but not size, may help to explain physical function.

Lumbar multifidus muscle changes in unilateral lumbar disc herniation using magnetic resonance imaging

OBJECTIVE

To assess multifidus muscle asymmetry using the cross-sectional area (CSA) and perpendicular distance of the multifidus muscle to the lamina (MLD) measurements in patients with nerve compression due to lumbosacral disc hernia.

MATERIALS AND METHODS

In total, 122 patients who underwent microdiscectomy for unilateral radiculopathy caused by disc herniation, diagnosed by magnetic resonance imaging (MRI), were evaluated retrospectively. Posterolateral or foraminal disc herniation at only one disc level, the L3-4, L4-L5, or L5-S1 region, was confirmed using MRI. Subjects were divided by symptom duration: 1-30 days, (group A), 31-90 days (group B), and > 90 days (group C). There were 48 cases in group A, 26 in group B, and 48 in group C.

RESULTS

In groups A, B, and C, the median MLD differed significantly between the diseased and normal sides (P < 0.05). The MLD increased on the diseased side with symptom duration by lumbar disc herniation. The diseased side MLD was 5.1, 6.7, and 7.6 mm in groups A, B, and C, respectively (P < 0.05). The cut-off values for the MLD measurements were 5.3 mm (sensitivity = 62.3%, specificity = 55.5%; P < 0.05). In groups A, B, and C, the median CSA of the multifidus muscle was not significantly different between the diseased and the normal side (P > 0.05).

CONCLUSIONS

The MLD measurement correlated significantly with multifidus asymmetry in patients with lumbar disc herniation.