Paraspinal Muscle Atrophy Research Articles

Abdominal aortic calcification is independently associated with increased atrophy and fatty infiltration of the lumbar paraspinal muscles: a retrospective cross-sectional study.

Aortic abdominal calcification (AAC) is associated with spine-related conditions, such as lower back pain and reduced bone mineral density. Similar to peripheral vascular disease, AAC possibly reduces blood flow to the lumbar posterior paraspinal muscles (PPM) which may lead to atrophy and increased fatty infiltration. Imaging of patients with lower back pain was analyzed. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. The cross-sectional area of the PPM was measured on a T2-weighted axial MRI sequence and the functional cross-sectional area (fCSA) and fatty infiltration (FI) were calculated with custom software. The association of AAC and FI as well as AAC and fCSA was assessed by multivariable linear regression, adjusted for age, sex, body mass index (BMI), diabetes, and smoking. Two hundred and thirty patients (47.8% female) with a median age of 60years (IQR 48-68) were analyzed. In patients, without AAC the median FI of the PPM was 33.3% (IQR 29.1-37.6%), compared to 44.6% (IQR 38.5-54.3%) in patients with AAC (p < 0.001). In the multivariable linear regression, both fCSA and FI of the PPM were significantly and independently associated with the degree of AAC (p = 0.037 and p = 0.015, respectively). This is the first study to demonstrate a significant and independent association between AAC and PPM morphology. The results of this study improve our understanding of the interaction between AAC and spinal musculature, with AAC being a reason for atrophy of the PPM.

Facet Joint Orientation/Tropism Could Be Associated with Fatty Infiltration in the Lumbar Paraspinal Muscles

Facet joint orientation (FJO) and facet joint tropism (FJT) are associated with intervertebral disc degeneration and paraspinal muscle atrophy. However, none of the previous studies has evaluated the association of FJO/FJT with fatty infiltration in the multifidus, erector spinae, and psoas muscles at all lumbar levels. In the present study, we aimed to analyze whether FJO and FJT were associated with fatty infiltration in the paraspinal muscles at any lumbar level. Paraspinal muscles and FJO/FJT were evaluated from L1-L2 to L5-S1 intervertebral disc levels on T2-weighted axial lumbar spine magnetic resonance imaging. Facet joints were more sagittally and coronally oriented at the upper and lower lumbar levels, respectively. FJT was more obvious at lower lumbar levels. The FJT/FJO ratio was higher at upper lumbar levels. Patients with sagittally oriented facet joints at the L3-L4 and L4-L5 levels had fattier erector spinae and psoas muscles at the L4-L5 level. Patients with increased FJT at upper lumbar levels had fattier erector spinae and multifidus at lower lumbar levels. Patients with increased FJT at the L4-L5 level had less fatty infiltration in the erector spinae and psoas at the L2-L3 and L5-S1 levels, respectively. Sagittally oriented facet joints at lower lumbar levels could be associated with fattier erector spinae and psoas muscles at lower lumbar levels. The erector spinae at upper lumbar levels and psoas at lower lumbar levels might have become more active to compensate the FJT-induced instability at lower lumbar levels.

Decompression via unilateral biportal endoscopy for severe degenerative lumbar spinal stenosis: A comparative study with decompression via open discectomy.

Previous studies have shown that the Unilateral Biportal Endoscopy is an effective and safety surgery for sufficient decompression of degenerative lumbar spinal stenosis. However, data are lacking in terms of its benefits when compared with conventional open lumbar discectomy (OLD), especially in patients with severe degenerative lumbar spinal stenosis (DLSS). To compare the clini cal outcomes of two types decompressive surgery: unilateral biportal endoscopy-unilateral laminectomy bilateral decompression (UBE-ULBD) and conventional open lumbar discectomy (OLD) in severe degenerative lumbar spinal stenosis (DLSS). We retrospectively analyzed patients who underwent UBE-ULBD (n = 50, operated at 50 levels; UBE-ULBD group) and conventional open lumbar discectomy (n = 59, operated at 47 levels; OLD group) between February 2019 and July 2021. All patients were diagnosed with severe stenosis based on the Schizas classification (Grade C or D) on MRI. We compared radiographic and clinical outcome scores [including the visual analog scale (VAS), Oswestry Disability Index (ODI), and Zurich Claudication Questionnaire (ZCQ)] between the 2 groups at 1 year of follow-up. The radiographic evaluation included the cross-sectional area (CSA) of the thecal sac and paraspinal muscles on MRI. Fasting blood was drawn before and 1 and 7 days after the operation to detect creatine kinase (CK). Surgical data perioperative complications were also investigated. The baseline demographic data of the 2 groups were comparable, including VAS, ODI and ZCQ scores, the cross-sectional area of the thecal sac and paraspinal muscles and creatine kinase levels. The dural sac CSA significantly increased post -operatively in both groups, which confirmed they benefited from comparable decompressive effects. The operative duration in the OLD group was less than the UBE-ULBD group (43.9 ± 5.6 min vs. 74.2 ± 9.3 min, p < 0.05). The OLD group was associated with more estimated blood loss than the UBE-ULBD group (111.2 ± 25.0 ml vs. 41.5 ± 22.2 ml, P < 0.05). The length of hospital stay (HS) was significantly longer in the OLD group than in the UBE-ULBD group (6.8 ± 1.6 vs. 4.0 ± 1.4 days, P < 0.05). The VAS, ODI, and ZCQ scores improved in both groups after the operation. Serum creatine kinase values in the UBE-ULBD group were significantly lower than in the OLD group at 1 day after surgery (108. 1 ± 11.9 vs. 347.0 ± 19.5 U/L, P < 0.05). The degree of paraspinal muscle atrophy in the UBE-ULBD group was significantly lower than in the OLD group at 1 year (4.50 ± 0.60 vs. 11.42 ± 0.87, P < 0.05). UBE-ULBD and conventional OLD demonstrate comparable short-term clinical outcomes in treating severe DLSS. However, UBE-ULBD surgery was associated with a shorter hospital stay, less EBL and paravertebral muscle injury than OLD surgery.

Are paraspinal muscle quantity, lumbar indentation value, and subcutaneous fat thickness related to disc degeneration? An MRI-based study

IntroductionThe aim of the study was to investigate the relationship between lumbar disc herniation and Goutallier classification (GC), lumbar indentation value, and subcutaneous adipose tissue thickness. Methods102 consecutive patients (59 female and 43 male) with lumbar back pain, numbness, tingling, or pain in the lower extremity indicating radiculopathy who had undergone lumbar magnetic resonance imaging (MRI) and had an intervertebral disc herniation in the L4-5 level, were included in the study. 102 patients who have undergone lumbar MRI in the same time period and have no disc herniation were chosen to be the control group and were selected so as to match the herniated group for sex and age. All these patients’ scans were re-interpreted regarding paraspinal muscle atrophy (using the GC), lumbar indentation value, and subcutaneous adipose tissue thickness in the L4-5 level. ResultsThe Goutallier score was higher in the herniated group, compared with the non-herniated group (p < 0.001). There was no statistical difference between herniated and non-herniated groups regarding lumbar indentation value (LIV) and subcutaneous adipose tissue thickness (SATT). A Goutallier score of 1.5 provided the highest sensitivity x specificity value to indicate the disc herniation according to the statistical results. The individuals with a Goutallier score of 2, 3, and 4 have 2.87 times more likely to have disc herniation in their MRIs than the ones with a score of 0 and 1. ConclusionParaspinal muscle atrophy seems to be related to the presence of disc herniations. The cut-off value of GC to indicate the disc herniation in this study might be useful to predict the risk for disc herniation regarding the Goutallier score. The LIV and SATT measured in magnetic resonance images were randomly distributed between individuals with herniated and non-herniated groups, and statistically, no relationship was observed between these groups regarding these parameters. Implications for practiceThe effect of the parameters studied in this research on disc herniations are expected to be an added value to the literature. The awareness of risk factors for intervertebral disc herniations might be used in preventive medicine to predict the risk and understand the tendency of an individual for disc herniations to occur in the future. Further investigations are needed to establish whether there is a causal relationship or correlation between these parameters and disc herniation.

Paraspinal muscles atrophy on both sides and at multiple levels after unilateral lumbar partial discectomy.

To identify the changes in cross-sectional areas (CSAs) and fatty infiltration of both sides of the paravertebral muscles and their associations with prognostic factors in patients who underwent unilateral lumbar discectomy. We retrospectively reviewed 27 patients who underwent magnetic resonance imaging before and after 1- or 2-level lumbar discectomy. The CSAs and functional cross-sectional areas of the paraspinal muscles were bilaterally measured from L1 to L2 to L5 to S1 based on T2-weighted axial images. These parameters were compared pre-and postoperatively. CSAs and functional cross-sectional areas decreased also in non-operative, non-surgical levels, not only in operated levels after discectomy. In the correlation analysis, the CSA of psoas major muscle at L1 to L2 was significantly decreased in patients with lower preoperative lordosis (r = 0.598, P = .040). The postoperative CSA of psoas major muscle at L4 to L5 was lower in those with the higher Pfirrmann grade (r = -0.590, P = .002); however, the CSA of quadratus lumborum muscle at L1 to L2 showed the opposite result (r = 0.526, P = .036). Similar results were also observed in the partial correlation adjusted for age and postoperative duration. Patients who underwent discectomy experienced overall paraspinal muscle atrophy in the lumbar region, including surgical and non-surgical sites. Such atrophic changes emphasized the need for core strengthening and lumbar rehabilitation from the early period after partial discectomy.

Identification of preoperative radiological risk factors for reoperation following percutaneous endoscopic lumbar decompression to treat degenerative lumbar spinal stenosis.

This study aimed to identify radiological risk factors associated with reoperation after percutaneous transforaminal endoscopic decompression (PTED) for degenerative lumbar spinal stenosis (DLSS). The preoperative clinical data of 527 consecutive patients with DLSS who underwent PTED were retrospectively reviewed. Overall, 44 patients who underwent reoperation were matched for age, sex, body mass index, and surgical segment to 132 control patients with excellent or good clinical outcomes. Radiological characteristics were compared between the groups using independent sample t-tests and Pearson's chi-square tests. A predictive model was established based on multivariate logistic regression analysis. The analyses revealed significant differences in the presence of lumbosacral transitional vertebra (LSTV, 43.2% vs. 17.4%, p = 0.001), the number of levels with senior-grade disc degeneration (2.57 vs. 1.96, p = 0.018) and facet degeneration (1.91 vs. 1.25 p = 0.002), and the skeletal muscle index (SMI, 849.7 mm2/m2 vs. 1008.7 mm2/m2, p < 0.001) between patients in the reoperation and control groups. The results of the logistic analysis demonstrated that LSTV (odds ratio [OR] = 2.734, 95% confidence interval [CI]:1.222-6.117, p < 0.014), number of levels with senior-grade facet degeneration (OR = 1.622, 95% CI:1.137-2.315, p = 0.008), and SMI (OR = 0.997, 95% CI:0.995-0.999, p = 0.001) were associated with reoperation after PTED. The application of the nomogram based on these three factors showed good discrimination (area under the receiver operating characteristic curve 0.754, 95% CI 0.670-0.837) and good calibration. LSTV, more levels with senior-grade facet degeneration, and severe paraspinal muscle atrophy are independent risk factors for reoperation after PTED. These factors can thus be used to predict reoperation risk and to help tailor treatment plans for patients with DLSS.

Correlation between posterior paraspinal muscle atrophy and lumbar intervertebral disc degeneration in patients with chronic low back pain.

Although enormous studies have been devoted to solving the problem of intervertebral disc degeneration/herniation, little attention is paid to the effect of paraspinal muscles on it. We aimed to investigate the correlation between paraspinal muscle atrophy and lumbar disc degeneration to recognize paraspinal muscle atrophy and its importance to the spine. A total of 107 patients were enrolled in the study (65 females, 42 males; age 50.87 ± 15.391years old). Cross-sectional area, functional cross-sectional area, and fatty infiltration of the posterior paraspinal muscles were measured at the level of L4/5, and the degree of facet joint degeneration was evaluated at the levels of L3/4, L4/5, and L5/S1 by MRI. After controlling the confounding factors by multiple linear regression, the correlations among paraspinal muscle atrophy, disc degeneration, and facet joint degeneration were analyzed. Meanwhile, Pearson/Spearson rank analysis was used to analyze the correlation between clinical symptoms (VAS and ODI) and paraspinal muscle atrophy. There was a strong correlation between paraspinal muscle atrophy and disc degeneration after controlling the confounding factors (p < 0.05, R > 0.5). There was a weak correlation between paraspinal muscle atrophy and facet joint degeneration (p < 0.05, R < 0.5). There was a significant correlation between facet joint degeneration and intervertebral disc degeneration (p < 0.05, R > 0.7). The fatty infiltration of paraspinal muscle was weakly correlated with ODI (p < 0.05, R < 0.3), but VAS was not. The degree of paraspinal muscle atrophy increased with lumbar disc degeneration and facet joint degeneration and fatty infiltration of multifidus was more susceptible to weight.

A Clinical Pilot Study Showing the Safety and Efficacy of Intramuscular Injection of Atelocollagen for Prevention of Paraspinal Muscle Atrophy after Spine Surgery

Objective: The objective of this study was to assess the safety and efficacy of intramuscular injection of atelocollagen for the prevention of paraspinal muscle atrophy after spine surgery. Atelcollagen has been widely used as an intradermal filler to restore soft tissue defect. Many studies demonstrated that atelocollagen provides good therapeutic results by promoting cell proliferation and enhances the healing effect on injured connective tissues such as tendons and fasciae, while causing few complications. Methods: A total of 118 patients who underwent single level of posterior lumbar interbody fusion (PILF) between December 2017 and April 2019 were retrospectively reviewed. In the study group of 60 patients, 3 mL of gel-type 3% atelocollagen solution was prepared and injected into the multifidus muscle during wound closure. Clinical efficacy was evaluated by the improvement of back pain, elevation of a muscle enzyme, and inflammatory markers. Radiologic efficacy was evaluated with a comparison of density and cross-sectional area (CSA) of multifidus and erector spinae muscle in CT images. Results: Visual analogue scale (VAS) scores for back pain was not significantly lower in the study group postoperatively compared with the control group. The reduction of postoperative paraspinal muscle density and CSA was significantly lower in the study group. The serum level of muscle enzyme and inflammatory markers were significantly lower in the study group. No major procedure-related complications were observed during the follow-up period.Conclusion: Intramuscular injection of atelocollagen is safe and feasible for the prevention of paraspinal muscle atrophy after spine surgery. This novel method seems advantageous for accelerating wound healing without causing inflammation.

Relationships between Paraspinal Muscle and Spinopelvic Sagittal Balance in Patients with Lumbar Spinal Stenosis.

ObjectiveTo investigate the relationships between measurements of paraspinal muscle and spinopelvic sagittal parameters and the predictive value of lumbar indentation value (LIV) on sagittal balance in patients with lumbar spinal stenosis.MethodsIt was a retrospective study. We collected the data of 110 patients, who were diagnosed as lumbar spinal stenosis from December 2018 to May 2019. The total cross‐sectional area (tCSA), functional cross‐sectional area (fCSA), and fatty infiltration (FI) of paraspinal muscle were measured. The spinopelvic sagittal parameters were also measured, including sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and PI minus LL (PI‐LL). Correlations between measurements of paraspinal muscle and sagittal parameters were investigated by Pearson correlation analysis. The multiple linear regression analysis was used to investigate the LIV, age, gender, and BMI for assessing spinopelvic sagittal balance. Receiver‐operating characteristic (ROC) curve was used to find out the most optimum cut‐off point of LIV for evaluating SVA.ResultsThere were 42 males and 68 females in this study and the mean age was 59.9 ± 10.9 years old. By Pearson correlation analysis, MF tCSA showed significant association with LL (r = 0.455, P < 0.01) and PI‐LL (r = −0.286, P < 0.01). MF fCSA had a significant correlation with LL (r = 0.326, P < 0.01) and PI‐LL (r = −0.209, P < 0.05). LIV was also significantly correlated to spinopelvic sagittal parameters, including SVA (r = −0.226, P < 0.05), LL (r = 0.576, P < 0.01), TK (r = 0.305, P < 0.01), and PI‐LL (r = −0.379, P < 0.01). By multiple linear regression analysis, LIV was independently associated with sagittal parameters, including PI‐LL and SVA. The cut‐off value of LIV for SVA ≤ 50 mm was 10.5 mm (AUC = 0.641). According to the best cut‐off value, patients were divided into two groups. For patients with LIV ≤ 10.5 mm, the percentage of SVA ≤ 50 mm was 54.5% (18/33), while it was 83.1% (64/77) for patients with LIV >10.5 mm.ConclusionsAs a new index to evaluate paraspinal muscle atrophy, the LIV was independently correlated to spinopelvic sagittal balance. Degeneration of paraspinal muscle was associated with spinopelvic sagittal balance.

Lumbar Multifidus Muscle Fatty Atrophy and Lumbar Disc Degeneration: Are they Associated in Middle Aged Patients with Low Backache?

Introduction: Low backache being one of the most common problems faced in the society mainly due to sedentary lifestyle and reduced physical activity which inturn leads to overweight, obesity and atrophy of paraspinal muscles. Disc prolapse is one of the most common causes of low backache. Hence, knowing the aetiological factors and treatment of the same at an early stage is beneficial. Aim: To determine the association between the grades of lumbar disc degeneration with degree of fatty infiltration of lumbar multifidus muscle in middle aged patients with low backache using Magnetic Resonance Imaging (MRI). Materials and Methods: A prospective observational study was conducted from April 2020 to February 2021 in Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India, with a study population of 201 middle aged patients who complaints of low back pain for more than three months. All patients who met the inclusion and exclusion criteria underwent plain MRI for Lumbosacral (LS) spine with 16 channel 1.5 tesla strength MR machine. Lumbar intervertebral disc degeneration was graded according to the Pfirrmann classification using T2 sequence in the sagittal plane. For the evaluation of the degree of fatty infiltration of lumbar multifidus muscle, axial T2-weighted slices were used to detect the cross-sectional area of the right and left lumbar multifidus muscle involvement. Chi-square test was used to find the association between varying grades of disc degeneration and severity of fat infiltration at Lumbar (L)4-L5 and L5-Sacral (S) 1 regions. Results: There was significant association between the grade of lumbar disc degeneration and the degree of atrophy of multifidus muscle with p-value &lt;0.001 in middle aged patients with low backache. There was significant relation with fatty muscle infiltration with a p-value of &lt;0.001 in L4-L5 and 0.03 in L5-S1 disc spaces. Most of the patients had grade III intervertebral disc degeneration in both L4/L5 and L5/S1. Conclusion: Lumbar multifidus muscle atrophy is common in grade 3 Pfirrmann classification of lumbar disc degeneration at both L4/L5 and L5/S1 levels.

Inter-examiner reliability in identifying lumbar paraspinal muscle atrophy by lumbar paraspinal muscle atrophy index, a novel parameter.

[Purpose] To evaluate the inter-examiner reliability of our novel parameter, the lumbar paraspinal muscle atrophy index, in identifying the lumbar paravertebral muscle atrophy. [Participants and Methods] The study group consisted of 225 adults, with a mean age of 64.7 (range, 21-89) years, who underwent posterior lumbar spinal surgery for degenerative spinal disease at our hospital between July 2013 and June 2017. Preoperative axial T2-weighted magnetic resonance images were used to evaluate the lumbar paraspinal muscle atrophy index and observe the presence or absence of severe lumbar paraspinal muscle atrophy. The lumbar paraspinal muscle atrophy index was calculated at each intervertebral level, from L1-2 through L4-5, once by two examiners, and the Cohen's kappa statistic was used to calculate the inter-examiner agreement of the classification of the presence or absence of atrophy at each level. [Results] The agreement was high (kappa, 0.79-0.88) for the lumbar paraspinal muscle atrophy index at all levels, except at the L3-4 level (kappa, 0.49). The lower kappa statistic at L3-4 likely reflects the unique morphological characteristics at this level. [Conclusion] The lumbar paraspinal muscle atrophy index is a new, simple, easy-to-use, and sufficiently reliable parameter to identify lumbar paraspinal atrophy.

The effect of posterior lumbar dynamic fixation and intervertebral fusion on paraspinal muscles

BackgroundThe aim of this study was to analyze the effect of unilateral K-rod dynamic internal fixation on paraspinal muscles for lumbar degenerative diseases.MethodsThis study retrospectively collected 52 patients who underwent lumbar surgery with the K-rod group or PLIF. The operation time, intraoperative blood loss, postoperative drainage volume, postoperative exercise time were compared in the two groups. The visual analog scale (VAS) score and the oswestry dysfunction index (ODI) were employed to evaluate the clinical outcomes. The functional cross-sectional area (FCSA) of the paraspinal muscles and paraspinal muscles fat infiltration were measured to assess on the paraspinal muscles.ResultsAs compared with the PLIF group, the operation time, the postoperative time in the field, and the average postoperative hospital stay in the K-rod internal fixation group were significantly shortened. At the last follow-up, both the groups showed significant improvement in the VAS score and ODI. The FCSA atrophy of the upper and lower adjacent segments (UAS and LAS) of the K-rod internal group was significantly less than that of the PLIF group. The extent of increase in the fatty infiltration of the paraspinal muscles in the K-rod group was significantly lesser than that in the PLIF group. The postoperative low back pain of the two groups of patients was significantly positively correlated with the FCSA atrophy.ConclusionsAs compared to PLIF, the posterior lumbar unilateral K-rod dynamic internal fixation showed significantly lesser paraspinal muscle atrophy and fatty infiltration, which were significantly positively correlated with postoperative low back pain.

Vitamin D inadequacy combined with high BMI affects paraspinal muscle atrophy and pain intensity in postmenopausal women

Objective This study was performed to assess the effects of vitamin D deficiency/insufficiency combined with a high body mass index (BMI) on paraspinal muscle (PSM) atrophy and pain intensity in postmenopausal women with lower back pain (LBP). Methods In total, 365 postmenopausal women were analyzed in the study. We divided the women into four groups according to BMI and vitamin D status. Outcome measurements included PSM atrophy, fatty infiltration (FI) and severity of LBP. Binary logistic regression was used to analyze the odds ratio (OR), and the interaction between the BMI and vitamin D status was tested. Results Compared with the control group, the high BMI with vitamin D deficiency/insufficiency group had a significantly increased risk of FI > grade 2 (OR = 10.69, p < 0.001), hand grip strength of <16 kg (OR = 8.96, p < 0.001), Short Physical Performance Battery score of ≤8 (OR = 3.69, p < 0.001) and visual analog scale (VAS) score of >3 (OR = 4.76, p < 0.001). A significant positive additive interaction was found between the BMI and vitamin D status on PSM atrophy. Conclusion Vitamin D deficiency/insufficiency combined with a high BMI was associated with PSM atrophy and LBP intensity in postmenopausal women. The interaction analysis showed a positive additive interaction between BMI and vitamin D status.

Assessing Fatty Infiltration of Paraspinal Muscles in Patients With Lumbar Spinal Stenosis: Goutallier Classification and Quantitative MRI Measurements.

Objective: Fatty infiltration of paraspinal muscle is associated with spinal disorders. It can be assessed qualitatively (i.e., Goutallier classification) and quantitatively using image processing software. The aims of this study were to compare paraspinal muscle fatty infiltration as assessed using the Goutallier classification vs. quantitative magnetic resonance images (MRI) measurements and to investigate the association between anthropometric parameters and paraspinal muscle morphology and fatty infiltration in patients with symptomatic lumbar spinal stenosis (LSS).Methods: Patients affected by symptomatic LSS scheduled for surgery with available MRI of the lumbar spine were included in this retrospective cross-sectional study. Fatty infiltration at each lumbar level was rated qualitatively according to the Goutallier classification and quantified based on the cross-sectional area (CSA) of the paraspinal muscle, of its lean fraction (LeanCSA), and the ratio between LeanCSA and CSA and the CSA relative to the CSA of vertebral body (RCSA). Considering the muscle as a single unit, overall fatty infiltration according to Goutallier, overall CSA, LeanCSA, LeanCSA/CSA, and RCSA were computed as averages (aGoutallier, aCSA, aLeanCSA, aLeanCSA/aCSA, and aRCSA). Associations among parameters were assessed using Spearman's respective Pearson's correlation coefficients.Results: Eighteen patients, with a mean age of 71.3 years, were included. aGoutallier correlated strongly with aLeanCSA and aLeanCSA/aCSA (R = −0.673 and R = −0.754, both P < 0.001). There was a very strong correlation between values of the left and right sides for CSA (R = 0.956, P < 0.001), LeanCSA (R = 0.900, P < 0.001), and LeanCSA/CSA (R = 0.827, P < 0.001) at all levels. Among all anthropometric measurements, paraspinal muscle CSA correlated the most with height (left: R = 0.737, P < 0.001; right: R = 0.700, P < 0.001), while there was a moderate correlation between vertebral body CSA and paraspinal muscle CSA (left: R = 0.448, P < 0.001; right: R = 0.454, P < 0.001). Paraspinal muscle CSA correlated moderately with body mass index (BMI; left: R = 0.423, P < 0.001; right: R = 0.436, P < 0.001), and there was no significant correlation between aLeanCSA or aLeanCSA/CSA and BMI.Conclusions: The Goutallier classification is a reliable yet efficient tool for assessing fatty infiltration of paraspinal muscles in patients with symptomatic LSS. We suggest taking body height as a reference for normalization in future studies assessing paraspinal muscle atrophy and fatty infiltration.

204. A clinical pilot study showing the safety and efficacy of intramuscular injection of atelocollagen for prevention of paraspinal muscle atrophy after spine surgery

<h3>BACKGROUND CONTEXT</h3> Atelocollagen has been widely used as an intradermal filler to restore soft tissue defects. Many studies demonstrated that atelocollagen provides good therapeutic results by promoting cell proliferation and enhances the healing effect on injured muscles and connective tissues such as tendons and fasciae while causing few complications. <h3>PURPOSE</h3> This clinical study was designed to assess the safety and efficacy of intramuscular injection of atelocollagen for the prevention of paraspinal muscle atrophy after spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective observational study. <h3>PATIENT SAMPLE</h3> A total of 118 patients who underwent single- or two-level posterior lumbar interbody fusion (PILF) between December 2017 and April 2019 were retrospectively reviewed. <h3>OUTCOME MEASURES</h3> Clinical efficacy was evaluated by the improvement of back pain, elevation of a muscle enzyme, and inflammatory markers. Radiologic efficacy was evaluated with a comparison of density and cross-sectional area (CSA) of multifidus and erector spinae muscle in CT images. The safety was assessed with vital sign monitoring and a survey on all adverse events over 12 weeks. <h3>METHODS</h3> In the study group of 30 patients, 3mL of gel-type 3% atelocollagen solution was prepared and injected into the multifidus muscle during wound closure. <h3>RESULTS</h3> Significant improvement of back pain was observed in all patients after the surgery. VAS for back pain was not significantly lower in the study group postoperatively compared with the control group. The reduction of postoperative paraspinal muscle density and CSA was significantly lower in the study group. The serum level of muscle enzyme and inflammatory markers were significantly lower in the study group. No major procedure-related complications were observed during the follow-up period. <h3>CONCLUSIONS</h3> Intramuscular injection of atelocollagen is safe and feasible for the prevention of paraspinal muscle atrophy after spine surgery. This novel method seems advantageous for accelerating wound healing without causing inflammation. Randomized controlled trials with larger data samples are needed to confirm the results. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Paraspinal muscle degeneration and regenerative potential in a Murine model of Lumbar Disc Injury

Background ContextThe association between low back pain and lumbar disc degeneration is not fully characterized. One potentially overlooked factor of this process is the lumbar multifidus, which plays a role in segmental stabilization and locomotion. Previous reports have shown multifidus degeneration to be associated with disc degeneration. The goal of this study was to develop a mouse model of advanced lumbar disc degeneration to recapitulate the pathology of the human multifidus in patients with lumbar disc degeneration and low back pain. MethodsC57BL/6 mice underwent a left anterolateral approach to the lumbar spine and disc puncture with a micro scalpel at L5/6 and L6/S1. Mice underwent behavioral analysis and functional gait testing. A subset of mice underwent 14T T2-weighted MRI to assess disc degeneration and paraspinal muscle quality. At 6 and 15 weeks, mice were sacrificed, and the multifidus muscles were harvested and divided into proximal and distal segments relative to disc injury. Histological analysis was performed to assess muscle degeneration, fiber type, and macrophage density. Fibroadipogenic progenitors (FAPs) were isolated for gene expression analysis with qPCR. ResultsMRI demonstrated decreased intervertebral disc signal and paraspinal muscle atrophy at 6 weeks, with progressive degeneration and atrophy at 15 weeks. Disc injury resulted in delayed functional recovery and impaired gait. Histology demonstrated progressive multifidus fibrofatty degeneration between 6 and 15 weeks. CD68+ macrophage density was increased at 6 weeks but not 15 weeks. FAPs exhibited increased fibrotic and adipogenic gene expression at 6 weeks compared to sham with less of a difference in gene expression by 15 weeks. ConclusionsWe have developed a mouse model of disc injury-mediated paraspinal muscle degeneration that recapitulates features of degenerative muscle pathology observed in patients with lumbar disc degeneration, and highlights the role of FAPs in mediating fibrofatty muscle degeneration after disc injury.

Novel LMNA mutation presenting with cardiomyopathy, paraspinal muscle atrophy and proximal lower extremity weakness. (4389)

Novel LMNA mutation presenting with cardiomyopathy, paraspinal muscle atrophy and proximal lower extremity weakness. (4389)

Preoperative paraspinal and psoas major muscle atrophy and paraspinal muscle fatty degeneration as factors influencing the results of surgical treatment of lumbar disc disease.

There is a growing number of publications highlighting sarcopenia and myosteatosis as poor prognosic factors for treatment results in oncological patients. The decrease in the cross-sectional area (CSA) of the multifidus muscle and muscle steatosis is associated with lumbar disc herniation and low back/limb pain. Nevertheless, no studies have analyzed the influence of the above parameters on patient satisfaction, pain decrease and return to daily activities. The aim of the study was to verify whether decreased preoperative CSA of the paraspinal and psoas major muscles and their fatty degeneration (myosteatosis) may influence the outcome of surgical treatment of lumbar disc disease (LDD). One hundred and one patients with LDD undergoing open microdiscectomy were enrolled in the analysis. Relative cross-sectional areas (rCSA) of the paraspinal and psoas major muscles as well as their fatty degeneration were measured. Patients were assessed according to the validated Polish versions of the EURO EQ-5D, Core Outcome Measure Index (COMI), Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) 1 and 6months postoperatively. The association between the variables was calculated using Pearson r and Spearman rank correlation. The Kruskal-Wallis test was used to compare the results between the groups with different rCSA of paraspinal and psoas major muscles and a different degree of paraspinal muscle myosteatosis. Fatty degeneration of the paraspinal muscles correlated with better outcomes 1 and 6months postoperatively according to ODI (P = 0.003 and P = 0.027, respectively). Patients with higher rCSA of the paraspinal and psoas major muscles achieved better results on the EURO EQ-5D scale (P = 0.0289 and P = 0.0089, respectively). Higher rCSA of the paraspinal and psoas major muscles did not correlate with better outcomes measured using ODI, COMI and VAS scales (P ≥ 0.072). The degree of fatty degeneration of the paraspinal muscles correlates with better outcomes 1 and 6months after microdiscectomy.

Review of Current Spinal Robotic Orthoses.

Osteoporotic spine fractures (OSF) are common sequelae of osteoporosis. OSF are directly correlated with increasing age and incidence of osteoporosis. OSF are treated conservatively or surgically. Associated acute pain, chronic disabilities, and progressive deformities are well documented. Conservative measures include a combination of initial bed rest, analgesia, early physiotherapy, and a spinal brace (orthosis), with the aim for early rehabilitation to prevent complications of immobile state. Spinal bracing is commonly used for symptomatic management of OSF. While traditional spinal braces aim to maintain the neutral spinal alignment and reduce the axial loading on the fractured vertebrae, they are well known for complications including discomfort with reduced compliance, atrophy of paraspinal muscles, and restriction of chest expansion leading to chest infections. Exoskeletons have been developed to passively assist and actively augment human movements with different types of actuators. Flexible, versatile spinal exoskeletons are designed to better support the spine. As new technologies enable the development of motorized wearable exoskeletons, several types have been introduced into the medical field application. We have provided a thorough review of the current spinal robotic technologies in this paper. The shortcomings in the current spinal exoskeletons were identified. Their limitations on the use for patients with OSF with potential improvement strategies were discussed. With our current knowledge of spinal orthosis for conservatively managed OSF, a semi-rigid backpack style thoracolumbar spinal robotic orthosis will reduce spinal bone stress and improve back muscle support. This will lead to back pain reduction, improved posture, and overall mobility. Early mobilization is an important part of management of patients with OSF as it reduces the chance of developing complications related to their immobile state for patients with OSF, which will be helpful for their recovery.

Assessing fatty infiltration of paraspinal muscles in patients with lumbar spinal stenosis: Goutallier classification and quantitative MRI measurements

Objective: Fatty infiltration of paraspinal muscle is associated with spinal disorders. It can be assessed qualitatively (i.e., Goutallier classification) and quantitatively using image processing software. The aims of this study were to compare paraspinal muscle fatty infiltration as assessed using the Goutallier classification vs. quantitative magnetic resonance images (MRI) measurements and to investigate the association between anthropometric parameters and paraspinal muscle morphology and fatty infiltration in patients with symptomatic lumbar spinal stenosis (LSS). Methods: Patients affected by symptomatic LSS scheduled for surgery with available MRI of the lumbar spine were included in this retrospective cross-sectional study. Fatty infiltration at each lumbar level was rated qualitatively according to the Goutallier classification and quantified based on the cross-sectional area (CSA) of the paraspinal muscle, of its lean fraction (LeanCSA), and the ratio between LeanCSA and CSA and the CSA relative to the CSA of vertebral body (RCSA). Considering the muscle as a single unit, overall fatty infiltration according to Goutallier, overall CSA, LeanCSA, LeanCSA/CSA, and RCSA were computed as averages (aGoutallier, aCSA, aLeanCSA, aLeanCSA/aCSA, and aRCSA). Associations among parameters were assessed using Spearman's respective Pearson's correlation coefficients. Results: Eighteen patients, with a mean age of 71.3 years, were included. aGoutallier correlated strongly with aLeanCSA and aLeanCSA/aCSA (R = -0.673 and R = -0.754, both P < 0.001). There was a very strong correlation between values of the left and right sides for CSA (R = 0.956, P < 0.001), LeanCSA (R = 0.900, P < 0.001), and LeanCSA/CSA (R = 0.827, P < 0.001) at all levels. Among all anthropometric measurements, paraspinal muscle CSA correlated the most with height (left: R = 0.737, P < 0.001; right: R = 0.700, P < 0.001), while there was a moderate correlation between vertebral body CSA and paraspinal muscle CSA (left: R = 0.448, P < 0.001; right: R = 0.454, P < 0.001). Paraspinal muscle CSA correlated moderately with body mass index (BMI; left: R = 0.423, P < 0.001; right: R = 0.436, P < 0.001), and there was no significant correlation between aLeanCSA or aLeanCSA/CSA and BMI. Conclusions: The Goutallier classification is a reliable yet efficient tool for assessing fatty infiltration of paraspinal muscles in patients with symptomatic LSS. We suggest taking body height as a reference for normalization in future studies assessing paraspinal muscle atrophy and fatty infiltration.