Defining Threshold values of Paraspinal Sarcopenia in Patients with Degenerative Lumbar Diseases

Defining Threshold values of Paraspinal Sarcopenia in Patients with Degenerative Lumbar Diseases | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Defining Threshold values of Paraspinal Sarcopenia in Patients with Degenerative Lumbar Diseases Abdukahar Kiram, Ming Wang, Jie Li, Yunlong Xu, Jingtan Hu, Qiang Liu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7085436/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction Emerging evidence shows that paraspinal sarcopenia is closely linked to adverse clinical outcomes in degenerative lumbar diseases (DLDs), including degenerative spinal deformity (DSD) and degenerative lumbar stenosis (DLS). However, its definition remains controversial, and precise diagnostic thresholds have yet to be established. Moreover, diagnostic criteria for paraspinal sarcopenia may differ across these DLD subtypes. Methods Patients with DLD were prospectively enrolled. Clinical outcomes included the SRS-22 and visual analog scale scores (VAS) for back pain and leg pain. Fat infiltration rate (FI%) of multifidus muscle was used to assess muscle mass loss. Endurance time (ET) and evaluating muscle maximal exert (MVE) were evaluated to determine paraspinal muscle performance and strength. Threshold values were determined by obtaining the upper or lower quartiles of measured data. Further, distinct and sex-specified threshold values for paraspinal sarcopenia were specifically established for each group. Furthermore, the predictive accuracy of paraspinal sarcopenia measurements for quality of life was assessed by calculating the area under the curve (AUC). Results A total of 342 patients enrolled in this study. The threshold values for paraspinal sarcopenia in DSD were: MF FI%>45%, MVE < 70N, and ET 31%, MVE < 86N, and ET 19.1%, MVE < 90N, and ET 25%, MVE < 106N, and ET < 17s for males. DSD patients with paraspinal sarcopenia had impaired HRQoL ( P = 0.004). The thresholds of paraspinal sarcopenia in DSD for worse back pain and SRS-22 scores were good with an AUC of 0.869 and 0.887. Conclusions Threshold values were obtained using paraspinal muscle data from patients with DSD and DLS, respectively. DSD patients with paraspinal sarcopenia exhibited more advanced degenerative spinal changes and poorer quality of life. These findings provide reference values for identifying patients with paraspinal sarcopenia. Paraspinal sarcopenia Degenerative spinal deformity Degenerative lumbar diseases Fat infiltration Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Due to the demographic shift, aging has become a major global health care concern[ 1 ]. As a major age-related musculoskeletal disease, degenerative lumbar disease is becoming more prevalent [ 2 , 3 ]. DLD leads to chronic pain, radiculopathy, and neurogenic claudication, which severely impair patients' health-related quality of life (HRQoL)[ 2 , 4 ]. Furthermore, most patients with DLD experience persistent pain that often necessitates spinal arthrodesis, resulting in an annual medical expenditure exceeding US $ 1.65 billion[ 5 , 6 ]. However, the development of appropriate noninvasive interventions to prevent adverse outcomes remains limited, primarily due to the insufficient identification of causative factors. Paraspinal sarcopenia has gained increasing attention for its contribution to poor outcomes in DLD[ 7 – 11 ]. Several studies have shown that both systemic and paraspinal sarcopenia disrupt spinal stability and affect disease progression and surgical outcomes in patients with DLD[ 12 ]. Emerging evidence suggests that paraspinal sarcopenia represents site-specific muscle loss that is distinct from systemic sarcopenia. Despite growing recognition of its clinical significance, the definition and diagnostic criteria for paraspinal sarcopenia remain inconsistent across the literature. Many studies define paraspinal sarcopenia as a component of systemic sarcopenia, commonly employing appendicular muscle mass and strength (e.g., grip strength) as diagnostic criteria[ 13 , 14 ]. This may lead to underestimation of paraspinal sarcopenia in patients with DLD. Other studies have defined paraspinal sarcopenia based on severe localized atrophy, using single morphological indicators such as multifidus muscle fat infiltration (≥ 50%). However, muscle morphology correlates only partially with functional impairment in patients with DLD[ 15 ], and may therefore be insufficient for identifying paraspinal sarcopenia. Such inconsistencies hinder effective screening and contribute to conflicting findings. As a result, there is a pressing need to establish a multimodal diagnostic framework tailored to patients with DLD and paraspinal sarcopenia. Current consensus defines sarcopenia as the presence of both low muscle mass and diminished muscle function (strength or performance)[ 13 ]. Studies have reported that endurance test (ET) and maximal voluntary exertion (MVE) are two widely accepted, objective methods for assessing paraspinal muscle performance and strength in DLD[ 16 ]. Muscle mass is typically assessed using morphological measures, such as muscle cross-sectional area and fat infiltration rate. Sch¨onnagell et al. diagnosed paraspinal sarcopenia using a multifidus muscle fat infiltration rate (MF FI) > 50%[ 17 ]. However, this threshold appears arbitrary and lacks sufficient validation based on patient characteristics. Furthermore, morphological measures reflect only muscle mass, not functional deficits. Thus, defining paraspinal sarcopenia in patients with DLD requires comprehensive threshold values encompassing both muscle function and mass. Specifically, DLD represents a spectrum of spinal disorders, including degenerative lumbar stenosis (DLS) and degenerative spinal deformity (DSD)[ 9 , 18 , 19 ]. DSD is a three-dimensional spinal deformity characterized by distorted paraspinal musculature. Multiple studies have reported significantly greater paraspinal muscle mass loss and functional decline in patients with DSD compared to those with DLS. Additionally, paraspinal muscle degeneration in DSD is often asymmetric, which uniquely compromises spinal stability and may reduce the diagnostic sensitivity for identifying paraspinal sarcopenia in patients with DSD. Furthermore, a sex-specific pattern has been observed in age-related paraspinal muscle loss and functional decline[ 20 ]. Therefore, this study aimed to establish sex-specific, disease-tailored diagnostic threshold values for paraspinal sarcopenia based on patients’ morphological and functional data and to examine its impact on patients’ QoL. Materials and methods Participations This study was approved by the ethical review committee of our institution. Patients with DLD (n = 157 for DLS and n = 106 for DSD, from December 2023 to April 2025) were prospectively enrolled. Inclusion criteria for DLS were age > 40 years, no kyphoscoliosis curvatures, and narrowed spinal canal on MRI images. Inclusion criteria for DSD patients were age > 40 years, Cobb angle of the main curve > 10°, or sagittal vertical axis > 5 cm. The exclusion criteria included any signs of deformity caused by other etiologies, history of spine surgery, spinal infection, tumor, and neuromuscular and connective tissue disorders. Informed consent was obtained from the enrolled participants before the study began. The workflow of this study is illustrated in Fig. 1 . Morphological assessments The paraspinal muscle cross-sectional area (CSA) and fat infiltration rate (FI%) were obtained using ImageJ (v54) on T2-weighted MRI images. The CSAs and FI% of the bilateral paraspinal muscle at the L3 level were evaluated as previously reported[ 21 ]. In addition, the ratio of FI% (Ro FI%) between bilateral muscles was calculated (left/right for DLS and concave/convex for DS) to indicate the asymmetric distribution of FI. A total of 725 MRI scans were analyzed. Figure 2 B. paraspinal muscle endurance test Endurance time was examined as previously reported. Briefly, patients were asked to lie in a prone position extend their back and maintain their maximal neck flexion until back fatigue. The best performance of the patients was used for further analysis. Patients with severe back pain were excluded in this study. Figure 2 A. muscle strength examination Paraspinal muscle strength was measured using hand-held dynamometry (Micro FET3, Hoggan Health Industries, Inc.), as previously reported[ 22 ]. Briefly, the patients were asked to lay in a prone position and perform a back extension with maximum strength. The test was performed three times, and the maximum effort was used in future analysis. Figure 2 C. Radiological parameters Standing anteroposterior radiographs were used to measure coronal and sagittal parameters, including the Cobb angle, coronal balance, pelvic incidence, sacral slope, pelvic tilt, sagittal vertical axis, and thoracic lordosis using Surgimap software (V26). Figure 2 D. Determination of paraspinal sarcopenia Paraspinal sarcopenia was defined as severe paraspinal muscle loss and poor strength with or without impaired muscle performance. Thresholds were obtained using upper or lower quartiles from the patients’ baselines as previously reported[ 23 ]. Accordingly, each parameter was classified into “poor”, “fair”, and “good” status. The lower quartile of MVE and ET were regarded as poor muscle function and the upper quartile of MF FI% was as severe muscle loss. The upper and lower quartile of RoFI% was used to determine asymmetric muscle loss in DSD. Accordingly, thresholds of gender-specified paraspinal sarcopenia for non-scoliotic DLD patients and DSD were determined. The characteristics of DSD patients with paraspinal sarcopenia To emphasize the characteristics of DSD patients with paraspinal sarcopenia, the demographic and radiological data were compared patients with and without paraspinal sarcopenia. Clinical outcomes were evaluated by the patient-reported questionnaires including SRS-22 and SVA back pain score. Finally, the ROC was performed to test the predictability of paraspinal sarcopenia measurements on adverse clinical outcomes in DSD patients. Statistical analysis All statistic was conducted in GraphPad Prism (V9) or RStudio (V4.2.2). The continuous data were shown in mean ± S.D or median and interquartile range (IQR). The difference between groups was tested by unpaired student t-tests or one-way ANOVA coupled with Fisher’s least significant difference (LSD) post-hoc test. Thresholds were obtained using upper or lower quartiles from the patients’ baselines as previously reported[ 23 ]. Accordingly, each parameter was classified into “poor”, “fair”, and “good” status. The area under the curve (AUC) of SDSS parameters was calculated to assess the predictability of measurements. AUC values of less than 0.7 were considered poor, 0.7 to 0.8 as acceptable, 0.8 to 0.9 as excellent, and greater than 0.9 as outstanding. Results A total of 342 patients were enrolled in the final analysis, among which 204 were DLS and 138 were DSD. The workflow of this study is illustrated in Fig. 1 . The baseline demographic and clinical characteristics of patients are listed in Table 1 . Most patients were female in both DSD and DLS groups (M/F: 21/117 vs 48/156, P = 0.06). There were no differences in age or BMI between the two groups. For the comorbidities, DSD patients showed a higher percentage of anemia (18.1% vs. 6.9%, P 0.05). Expectedly, radiological evaluations suggested DSD patients demonstrated severe sagittal misalignment, specifically the SVA of DLS was smaller compared to DSD ( P < 0.001), indicating severe spinal malalignment in DSD (Table 2 ). Paraspinal muscle morphological comparison The CSAs of MF, ES, and total muscle were comparable between the two groups, but the weighted MF FI% (34.82 ± 18.62 vs. 22.69 ± 12.25, P < 0.001) was higher in the DSD group compared to the DLS, indicating severe fatty replacement of paraspinal muscle in DSD. Expectedly, Ro FI% of paraspinal muscle was around 1 for DLS, but the ratio was higher in DSD (MF: 1.38 ± 0.45 vs. 1.02 ± 0.10, P < 0.001; ES: 1.18 ± 0.57 vs. 0.98 ± 0.17, P = 0.025). Table 3 . The measurements of patients’ data were performed by two authors (A.K and M.W), and Intra- and inter-rater coefficients were good to excellent for CSA, MF FI%, and paraspinal muscle measurements (ICC > 0.8) (Table 2 ). Paraspinal muscle functional evaluation and correlation analysis The median paraspinal muscle strength was 119.4N (IQR 95.38-143.35N) in DLS and 92.50N (IQR 73.01-118.05N) in DSD. Paraspinal strength was higher in the DLS group ( P < 0.001). The paraspinal muscle performance (ET) was higher in DLS with a median ET of 31.28s (IQR 19.27-43.52s) while 21.17s (IQR 10.64-33.27s) for DSD ( P 45% was defined as severe muscle mass loss, 32% was defined as severe muscle mass loss, 31% was severe, 25% was severe, < 15% was good, and 15 ~ 25% was fair for female patients with DLS. (Supplementary Fig. 1B). For paraspinal muscle strength, the MVE 115N was good, and 70N to 115N was fair for female patients with DSD (Fig. 3 C). The MVE 117N was good, and 117 ~ 115N was fair for male patients with DSD (Supplementary Fig. 1C). The MVE 133N was good, and 90 ~ 133N was fair for female patients with DLS (Fig. 3 D); The MVE 143N was good, and 107N ~ 143N was fair for female patients with DLS. (Supplementary Fig. 1D). Similarly, ET 32s was good, and 7s ~ 32s was fair for female patients with DSD. ET (Fig. 3 E). The ET 28s was good, and 6s ~ 28s was fair for male patients with DSD (Supplementary Fig. 1E). The ET 43s was good, and 15s ~ 43s was fair for female patients with DLS (Fig. 3 F). The ET 47s was good, and 17s ~ 47s was fair for male patients with DLS (Supplementary Fig. 1F). To assess the contribution of asymmetric muscle loss, an additional morphological parameter Ro FI% was assessed, and both upper and lower quintiles were calculated. The MF Ro FI%>1.3 or 45%, MVE < 70N, and ET 32%, MVE < 86N, and ET 19%, MVE < 90N, and ET 25%, MVE < 107N, and ET < 17s for males. The predictive role of paraspinal sarcopenia in HRQoL in patients with DLD The AUC of paraspinal sarcopenia parameters in DSD patients for VAS back pain score was 0.868. The AUC of SDSS parameters for the SRS-22 score, a questionnaire to reflect spine deformity-related health quality impairs, was 0.887 (Fig. 4 A). These results indicated excellent predictability of SDSS parameters regarding poor clinical outcomes in DSD. A representative case of DSD patients with paraspinal sarcopenia suffering back pain and low SRS-22 cores (deformity-related questionnaires) was shown in (Fig. 4 B). Characteristics of DSD patients with paraspinal sarcopenia To highlight the Characteristics of DSD patients with paraspinal sarcopenia, the demographic, radiological, and clinical outcome measurements including SVA back pain score and SRS-22 (Total) were compared patients with and without paraspinal sarcopenia. DSD patients with paraspinal sarcopenia were commonly advanced in age (with vs. without, 63.6 ± 6.4 vs 59.5 ± 5.8, P = 0.036), decreased lumbar lordosis ( P = 0.028) and with severe sagittal imbalance (with vs. without:103.84 ± 34.26mm vs 76.75 ± 42.81mm, P < 0.001). Table 5 . Accordingly, an algorithm for screening paraspinal sarcopenia for DLD patients (specifically for non-spine deformity and deformity patients) was proposed. Figure 5 . Discussion Paraspinal sarcopenia is widely recognized as a contributing factor in DLD. However, its definition remains controversial, and comprehensive diagnostic threshold values have not been determined. In this study, paraspinal sarcopenia was defined as the presence of both severe paraspinal muscle mass loss and dysfunction. Diagnostic thresholds were obtained using patients’ morphological and functional data. The sex-specific and disease-tailored threshold values for paraspinal sarcopenia in patients with DSD were: MF FI%>45%, MVE < 70N, and ET 31%, MVE < 86N, and ET 19.1%, MVE < 90N, and ET 25%, MVE < 106N, and ET < 17s for males. These thresholds demonstrated excellent predictive value for assessing HRQoL. This study provides disease-specific thresholds for paraspinal sarcopenia that correlate with reduced HRQoL, offering potential utility in identifying patients with compromised muscle health and informing intervention strategies to enhance paraspinal muscle function and HRQoL. Identifying driving factors is crucial for addressing the adverse outcomes of DLD and improving HRQoL. Paraspinal sarcopenia has emerged as a significant influencing factor and therapeutic target in patients with DLD. However, inconsistent findings across the literature may be attributed to variations in the definition and diagnostic methods used[ 13 ]. Many previous studies defined paraspinal sarcopenia as a localized manifestation of systemic sarcopenia and diagnosed it based on appendicular muscle mass and function. Consequently, reported prevalence rates range from 17–34% in DLS and 46–59% in DSD cases[ 25 – 28 ] , [ 29 ].Increasing evidence, however, suggests that paraspinal sarcopenia represents site-specific muscle loss distinct from systemic sarcopenia. Sch¨onnagel et al .[ 17 ] found that paraspinal sarcopenia is different from systemic sarcopenia in a relatively small sample of non-deformed DLD. Thus, diagnosing paraspinal sarcopenia using criteria intended for systemic sarcopenia may result in misclassification. It is therefore critical to establish a clear and specific definition to resolve discrepancies in research findings, standardize diagnostic protocols, and develop targeted interventions to improve spinal muscle health and HRQoL in patients with DLD. Determining precise diagnostic thresholds is essential for effectively identifying paraspinal sarcopenia in patients with DLD. The current consensus defines sarcopenia as the coexistence of muscle mass loss and dysfunction[ 30 ]. Kim et al. proposed a protocol to assess paraspinal sarcopenia[ 31 ]; however, their method was based on community-dwelling cohorts who may differ in presentation from patients with DLD, and it requires an isokinetic dynamometer that is not commonly available in clinical practice. Sch¨onnagel et al. defined severe paraspinal muscle atrophy (indicated by MF FI > 50%) as spinal-specific sarcopenia. However, this value reflects only muscle mass loss and does not account for muscle function. Moreover, prior studies reported MF FI% at the L3 level ranging from 22–35% in DLS[ 32 ]. In addition, paraspinal sarcopenia exhibits sex-based patterns in patients with DLD[ 20 , 30 , 33 ]. Therefore, using a cutoff of MF FI% >50% may be arbitrary and yield low diagnostic accuracy in DLS[ 34 ]. In the present study, we determined threshold for paraspinal muscle were MF FI%>19%, MVE < 90N, ET 25%, MVE < 107N, ET < 17s for males. Although changes in muscle strength have been reported in DLS, methodologies vary in the literature. Han et al.[ 16 ] enrolled 303 patients with DLS undergoing spinal fusion and categorized ET 60 s as good, differing from our findings. This discrepancy may result from differences in study populations. We included both outpatients and inpatients, whereas their study included only inpatients. Furthermore, to our knowledge, we were the first to determine threshold values of paraspinal sarcopenia for DSD. The Ro FI%>1.3 or 45% and > 31%were proposed as thresholds for severe muscle loss, ET < 7s and < 6s as poor muscle performance, MVE < 70N and < 86N as poor muscle function for female and male DSD patients, respectively. DSD is a multifactorial disease characterized by paraspinal muscle distortion that differs from that in DLS[ 9 ]. Several studies have reported more severe fatty infiltration and reduced muscle function in patients with DSD compared to those with DLS, consistent with our findings[ 35 ]. Additionally, bilateral paraspinal muscle in DSD often shows asymmetric degeneration, possibly resulting in varying degrees of sarcopenia. Previous studies have reported an average MVE of 85N in severe DSD; our findings were similar, with an average MVE of 86.9 N. However, no prior studies have determined a cutoff for poor muscle function in DSD. To characterize asymmetric muscle loss, we evaluated an additional parameter, Ro FI%, which had not been previously reported. Our findings help define reference values for diagnosing paraspinal sarcopenia and offer new tools for screening muscle dysfunction in patients with DSD. External validation is still necessary in future studies. We also explored characteristics of DSD patients with paraspinal sarcopenia. These patients tended to be older, have higher BMI, and exhibit poorer nutritional status (evidenced by anemia and hyperemia), suggesting more advanced degeneration. Patients with paraspinal sarcopenia also reported more severe HRQoL impairment. Diagnostic markers of paraspinal sarcopenia demonstrated strong predictive value for low back pain and SRS-22 scores, with AUC values of 0.81 and 0.863. Zhang et al.[ 36 ] reported that poor nutritional status is associated with lower HRQoL in patients with DSD. Advanced spinal degeneration and poor nutrition may underlie the impaired HRQoL in these patients. Thus, the proposed cutoff values not only effectively screen for paraspinal sarcopenia in patients with DSD but also identify those at risk for poor HRQoL. Nutritional support has been recognized as a key strategy for sarcopenia prevention[ 37 ]. However, given the significant differences between paraspinal and systemic sarcopenia, therapeutic approaches—such as nutritional intervention—should be tailored specifically for patients with paraspinal sarcopenia in DSD. The strengths of this study include the establishment of clear definitions and diagnostic thresholds for paraspinal sarcopenia in DLD, and the exploration of its clinical significance in the physical well-being of aged patients with DLD. However, this study has several limitations. First, it is a single-center study with a relatively small sample size; multicenter studies are warranted. Second, paraspinal muscle functional indices may vary across ethnicities, suggesting that ethnicity-specific thresholds should be developed. Third, due to limited sample size—particularly the small number of male participants—sex-specific thresholds may be underpowered. Finally, semi-quantitative methods were used to evaluate muscle morphology, and the relationship between morphology and function is not necessarily linear. Conclusion In summary, paraspinal sarcopenia was defined as both paraspinal muscle mass and function loss in this study, with gender specified and distinct thresholds for DLD patients. We were the first to determine the threshold values for diagnosing paraspinal sarcopenia for DLD patients with or without spinal deformity using basic morphological and functional data. The threshold values for paraspinal sarcopenia in DSD were: MF FI%>45%, MVE < 70N, and ET 31%, MVE < 86N, and ET 19.1%, MVE < 90N, and ET 25%, MVE < 106N, and ET < 17s for males. Finally, we found that DSD patients with paraspinal sarcopenia had a more advanced degenerative status and malnutrition, which correlated with poor HRQoL. The findings of the present study provided a practical tool for screening paraspinal sarcopenia in DLD patients and may aid in designing personalized patient care for the treatment of paraspinal sarcopenia. Declarations Author Contribution A.K. and M.W. conducted the measurements, analysis, and wrote the main manuscript.J.L. and Z.H. interpreted the acquired data.Y.X. and J.H. measured specific aspects of paraspinal muscle strength and endurance.Q.L. prepared Figures 1 and 5.Z.Z. and Y.Q. conceptualized and supervised the project.Z.L. provided critical revisions to the manuscript for important intellectual content, supervised the project, and offered financial support. References Tieland M, Trouwborst I, Clark BC (2018) Skeletal muscle performance and ageing. 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J Hepatol 75(1):S147–S162. 10.1016/j.jhep.2021.01.025 Tables Table 1: Comparison of demographic data, systemic and paraspinal sarcopenia measurements in DLS and DSD patients DSD DLS P- value Demographic information No. of participants 138 204 Age (y) 62.0±7.6 61.4±7.3 0.407 Gender (M/F) 21/117 48/156 0.060 BMI (kg/m 2 ) 25.7±4.2 25.3±4.5 0.342 Anemia (%) 25 (18.1%) 14(6.9%) 0.001 Hypoproteinemia (%) 13 (9.4%) 5 (2.5%) 0.005 Diabetes (%) 20 (14.5%) 24 (11.8%) 0.460 Hypertension (%) 29 (21.0%) 59 (28.9%) 0.101 Note : Data are presented as counts and percentages for categorical variables and mean ± standard deviation or median [first quartile, third quartile] for continuous variables. Abbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; BMI, body mass index. Table 2: Radiographic data comparison of enrolled degenerative spinal deformity and degenerative lumbar stenosis patients DSD DLS P -value Radiological parameters Cobb angle (°) 35.6±8.2 / / SS (°) 19.9±12.2 31.9±7.8 <0.001 PT (°) 22.2±13.1 17.4±7.4 0.021 PI (°) 42.3±12.4 49.7±8.1 0.008 LL (°) 21.1±28.3 41.9±12.3 <0.001 TK (°) 29.2±25.5 32.7±10.0 0.518 SVA (mm) 76.6±66.8 29.5±15.6 <0.001 Note : Data are presented as counts and percentages for categorical variables and mean ± standard deviation for continuous variables. Table 3: Comparison of demographic data, systemic and paraspinal sarcopenia measurements in DLS and DSD patients DSD DLS P- value Muscle function parameters ET (s) 17.6 [6.5, 30.5] 21.2 [8.1, 39.6] 0.026 MVE (N) 86.9 [67.5, 113.0] 106.6 [77.4, 134.8] 0.013 Morphological assessments Weighted CSA (MF) 78.7±43.6 82.3±32.5 0.523 Weighted CSA (ES) 136.2±58.7 142.8±47.8 0.427 Weighted FI% (MF) 34.8±18.6 22.6±12.2 <0.001 Weighted FI% (ES) 27.4±17.3 18.3±10.5 <0.001 Ro FI%(MF) 1.3±0.4 1.0±0.1 <0.001 Ro FI%(ES) 1.1±0.5 1.0±0.1 0.257 Note : Data are presented as counts and percentages for categorical variables and mean ± standard deviation or median [first quartile, third quartile] for continuous variables. Abbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; ET, endurance time; MVE, maximal voluntary exert force; MF, multifidus muscle: ES, erector spinae. Table 4: Intra- and inter-rater reliability test for measured parameters Intra-rater coefficient Inter-rater coefficient Radiological parameters Cobb angle (°) 0.93 0.91 SS (°) 0.89 0.92 PT (°) 0.95 0.94 PI (°) 0.91 0.93 LL (°) 0.95 0.90 TK (°) 0.84 0.92 SVA (mm) 0.96 0.94 Muscle function parameters ET (s) 0.86 0.92 MVE (N) 0.95 0.89 Morphological assessments CSA (cm 2 ) 0.93 0.94 FI% 0.95 0.87 Note : Abbreviations: SS, sacral slope; PT, pelvic tilt; PI, pelvic index; LL, lumbar lordosis; TK, thoracic kyphosis; SVA, sagittal vertical index; HGS, hand grip strength; ET, endurance time; MVE, maximal voluntary exert force; CSA, cross-sectional area; FI%, fat infiltration rate. Table 5 The comparison of basic characteristics and clinical outcomes of patients with SDSS and non-SDSS without systemic sarcopenia SDSS Non-SDSS P -value No. of participants 54 288 Age (y) 63.6±6.4 59.5±5.8 0.036 No. male/female 12/42 57/231 / BMI (kg/m 2 ) 25.8±5.3 25.2±4.2 0.357 Anemia (%) 19 (35.2) 20 (6.9) <0.001 Hypoproteinemia (%) 7(13.0) 11 (3.8) <0.001 Diabetes (%) 18 (33.3) 26 (9.0) <0.001 Hypertension (%) 15 (27.8) 73 (25.3) 0.708 VAS back pain score 5.8±2.6 5.0±2.0 <0.001 SS (°) 21.5±10.2 27.3±8.6 0.006 PT (°) 34.4±15.2 22.8±12.6 <0.001 PI (°) 55.2±12.8 49.5±10.7 0.427 LL (°) 19.6±17.5 38.8±14.1 0.028 TK (°) 29.4±18.2 33.2±18.3 0.874 SVA (mm) 83.8±44.2 34.75±22.8 <0.001 Note : Data are presented as counts and percentages for categorical variables and mean ± standard deviation for continuous variables. Abbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; BMI, body mass index; SS, sacral slope; PT, pelvic tilt; PI, pelvic index; LL, lumbar lordosis; TK, thoracic kyphosis; SVA, sagittal vertical index. Additional Declarations No competing interests reported. Supplementary Files FigureS3.tif Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7085436","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":487120384,"identity":"4ed6b9d8-3918-491d-a8b6-4e85f7db3118","order_by":0,"name":"Abdukahar Kiram","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Abdukahar","middleName":"","lastName":"Kiram","suffix":""},{"id":487120385,"identity":"3f15fa1d-bd41-4700-8cec-07c041cb67cb","order_by":1,"name":"Ming Wang","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Ming","middleName":"","lastName":"Wang","suffix":""},{"id":487120386,"identity":"e9ee5ede-5ab4-4a9a-afd7-15d122faea39","order_by":2,"name":"Jie Li","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Li","suffix":""},{"id":487120387,"identity":"11bbff45-f64b-4394-92dd-8d461078d4a2","order_by":3,"name":"Yunlong Xu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Yunlong","middleName":"","lastName":"Xu","suffix":""},{"id":487120388,"identity":"ab347933-0fd4-4795-a028-3157091c6610","order_by":4,"name":"Jingtan Hu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, Clinical College of Nanjing University of Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jingtan","middleName":"","lastName":"Hu","suffix":""},{"id":487120389,"identity":"437bdb7d-c64d-4b0a-8393-fd44fd160924","order_by":5,"name":"Qiang Liu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, Clinical College of Nanjing University of Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Qiang","middleName":"","lastName":"Liu","suffix":""},{"id":487120390,"identity":"afd9f094-b0a1-48c7-b5ba-eba8b57d385b","order_by":6,"name":"Zongshan Hu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Zongshan","middleName":"","lastName":"Hu","suffix":""},{"id":487120391,"identity":"67e3bbac-b319-4ca0-9d3f-156ebc3a51f4","order_by":7,"name":"Yong Qiu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Yong","middleName":"","lastName":"Qiu","suffix":""},{"id":487120392,"identity":"aae8016d-2b73-4169-bd6b-2b7268d780b8","order_by":8,"name":"Zezhang Zhu","email":"","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":false,"prefix":"","firstName":"Zezhang","middleName":"","lastName":"Zhu","suffix":""},{"id":487120393,"identity":"25b2d670-3cb7-42f5-af2d-93ffc333b023","order_by":9,"name":"Zhen Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwUlEQVRIiWNgGAWjYDCCA8wNB4AkAwN7Y+PDD8RpYYRq4TncbCxBrBYGsBaJ9DYBHmJ08N0+2HiY588dOXPJh20MEgx2croNBLRInktsOMzD88zYcnZi24MChmRjswMEtBicYQRqkTicuOF2YruBBMOBxG3EaTE4XL/h5sE2CR7itSQcTjC4wUikFkmgloNzDhw23HAmERjIBkT4he8M8+EPb/4cljc4fvzhww8VdnIEtaC7kzTlo2AUjIJRMApwAADXbUwX7Va3FgAAAABJRU5ErkJggg==","orcid":"","institution":"Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School","correspondingAuthor":true,"prefix":"","firstName":"Zhen","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2025-07-09 15:38:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7085436/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7085436/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87359809,"identity":"e2b074d8-ca24-4c84-9539-d70f2b2764cd","added_by":"auto","created_at":"2025-07-23 05:41:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":213438,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eWorkflow of the present study.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/e238575f740cfa1bfcbe6333.png"},{"id":87360726,"identity":"4dfb57c5-3fd3-454d-8240-2be5d7fc4d8d","added_by":"auto","created_at":"2025-07-23 05:49:19","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":432459,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe evolution of radiological, morphological, and functional parameters of paraspinal muscle. \u003c/strong\u003e(A) The muscle performance evaluation by endurance test. The maximal time for maintaining backward flexion was recorded. (B) Measurements of morphological data, including bilateral MF muscle (red circle), ES muscle (yellow circle). the CSA of the intervertebral disc (blue). Ro FI% is the ratio of bilateral paraspinal muscle (Concave/Convex for DSD, left/right for DLS). The red and white circle represents the concave and convex side, respectively. (C)The paraspinal muscle strength was obtained by measuring maximal voluntary exerting force. (D) Assessments of radiological data, including coronal and sagittal parameters. Indicated parameters were marked on X-ray images.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/1459793058cdf42986c5440d.png"},{"id":87359816,"identity":"7f2c54b8-9e48-4abc-b241-c82a6ef38174","added_by":"auto","created_at":"2025-07-23 05:41:19","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":131864,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThreshold determination of paraspinal sarcopenia in patients with DLD.\u003c/strong\u003e (A, B) The distribution of endurance time of patients with DSD (A) and DLS (B). The lower quintile was defined as poor muscle performance. (C, D) The distribution of maximal voluntary exerting force (MVE) of DSD (C) and DLS (D). The lower quartile of which was defined as poor muscle strength. (E, F) The distribution of weighted FI% of MF muscle of DSD (E) and DLS (F). The upper quintile was defined as severe paraspinal muscle mass loss. \u0026nbsp;(G) The distribution of Ro FI% of MF muscle of DSD. The upper and lower quintile of distributions were defined as severe paraspinal muscle mass loss.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/3dc65182edb6d90fba2aab44.png"},{"id":87359813,"identity":"e216ce43-7e13-4c16-9d97-e8363a9fa0d9","added_by":"auto","created_at":"2025-07-23 05:41:19","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":134913,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe predictability of paraspinal sarcopenia regarding HRQoL of DLD patients\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003eThe ROC-AUC analysis of paraspinal sarcopenia measurements to predict poor health-related quality of life scores (SRS-22) and high back pain scores (VAS\u0026gt;4) for DSD. (B) The ROC-AUC analysis of paraspinal sarcopenia measurements to predict high back pain scores (VAS\u0026gt;4) for DLS\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/f95c8aacd67ef7a16d93164c.png"},{"id":87360727,"identity":"012f5d01-5fae-4354-9244-b509d255fe34","added_by":"auto","created_at":"2025-07-23 05:49:20","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":863843,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSpecified diagnostic thresholds for defining paraspinal sarcopenia in DLD patients\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/3cac76a2c23affdc3992d596.png"},{"id":87364189,"identity":"6480dc10-e931-4680-aa87-33b8d3438f20","added_by":"auto","created_at":"2025-07-23 06:13:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3005180,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/6cc33440-f3fc-41b6-bf57-d090b674c98d.pdf"},{"id":87359814,"identity":"efc0d4c6-4748-4599-9899-57c703c68c7c","added_by":"auto","created_at":"2025-07-23 05:41:19","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":868834,"visible":true,"origin":"","legend":"","description":"","filename":"FigureS3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7085436/v1/90ccbb268b6ff4c2c4500ada.tif"}],"financialInterests":"No competing interests reported.","formattedTitle":"Defining Threshold values of Paraspinal Sarcopenia in Patients with Degenerative Lumbar Diseases","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDue to the demographic shift, aging has become a major global health care concern[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. As a major age-related musculoskeletal disease, degenerative lumbar disease is becoming more prevalent [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. DLD leads to chronic pain, radiculopathy, and neurogenic claudication, which severely impair patients' health-related quality of life (HRQoL)[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Furthermore, most patients with DLD experience persistent pain that often necessitates spinal arthrodesis, resulting in an annual medical expenditure exceeding US\u003cspan\u003e$\u003c/span\u003e1.65 billion[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, the development of appropriate noninvasive interventions to prevent adverse outcomes remains limited, primarily due to the insufficient identification of causative factors.\u003c/p\u003e\u003cp\u003eParaspinal sarcopenia has gained increasing attention for its contribution to poor outcomes in DLD[\u003cspan additionalcitationids=\"CR8 CR9 CR10\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Several studies have shown that both systemic and paraspinal sarcopenia disrupt spinal stability and affect disease progression and surgical outcomes in patients with DLD[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Emerging evidence suggests that paraspinal sarcopenia represents site-specific muscle loss that is distinct from systemic sarcopenia. Despite growing recognition of its clinical significance, the definition and diagnostic criteria for paraspinal sarcopenia remain inconsistent across the literature. Many studies define paraspinal sarcopenia as a component of systemic sarcopenia, commonly employing appendicular muscle mass and strength (e.g., grip strength) as diagnostic criteria[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. This may lead to underestimation of paraspinal sarcopenia in patients with DLD. Other studies have defined paraspinal sarcopenia based on severe localized atrophy, using single morphological indicators such as multifidus muscle fat infiltration (\u0026ge;\u0026thinsp;50%). However, muscle morphology correlates only partially with functional impairment in patients with DLD[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], and may therefore be insufficient for identifying paraspinal sarcopenia. Such inconsistencies hinder effective screening and contribute to conflicting findings. As a result, there is a pressing need to establish a multimodal diagnostic framework tailored to patients with DLD and paraspinal sarcopenia.\u003c/p\u003e\u003cp\u003eCurrent consensus defines sarcopenia as the presence of both low muscle mass and diminished muscle function (strength or performance)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Studies have reported that endurance test (ET) and maximal voluntary exertion (MVE) are two widely accepted, objective methods for assessing paraspinal muscle performance and strength in DLD[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Muscle mass is typically assessed using morphological measures, such as muscle cross-sectional area and fat infiltration rate. Sch\u0026uml;onnagell \u003cem\u003eet al.\u003c/em\u003e diagnosed paraspinal sarcopenia using a multifidus muscle fat infiltration rate (MF FI)\u0026thinsp;\u0026gt;\u0026thinsp;50%[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, this threshold appears arbitrary and lacks sufficient validation based on patient characteristics. Furthermore, morphological measures reflect only muscle mass, not functional deficits. Thus, defining paraspinal sarcopenia in patients with DLD requires comprehensive threshold values encompassing both muscle function and mass.\u003c/p\u003e\u003cp\u003eSpecifically, DLD represents a spectrum of spinal disorders, including degenerative lumbar stenosis (DLS) and degenerative spinal deformity (DSD)[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. DSD is a three-dimensional spinal deformity characterized by distorted paraspinal musculature. Multiple studies have reported significantly greater paraspinal muscle mass loss and functional decline in patients with DSD compared to those with DLS. Additionally, paraspinal muscle degeneration in DSD is often asymmetric, which uniquely compromises spinal stability and may reduce the diagnostic sensitivity for identifying paraspinal sarcopenia in patients with DSD. Furthermore, a sex-specific pattern has been observed in age-related paraspinal muscle loss and functional decline[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Therefore, this study aimed to establish sex-specific, disease-tailored diagnostic threshold values for paraspinal sarcopenia based on patients\u0026rsquo; morphological and functional data and to examine its impact on patients\u0026rsquo; QoL.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e\u003cb\u003eParticipations\u003c/b\u003e\u003c/p\u003e\u003cp\u003e This study was approved by the ethical review committee of our institution.\u003c/p\u003e\u003cp\u003ePatients with DLD (n\u0026thinsp;=\u0026thinsp;157 for DLS and n\u0026thinsp;=\u0026thinsp;106 for DSD, from December 2023 to April 2025) were prospectively enrolled. Inclusion criteria for DLS were age\u0026thinsp;\u0026gt;\u0026thinsp;40 years, no kyphoscoliosis curvatures, and narrowed spinal canal on MRI images. Inclusion criteria for DSD patients were age\u0026thinsp;\u0026gt;\u0026thinsp;40 years, Cobb angle of the main curve\u0026thinsp;\u0026gt;\u0026thinsp;10\u0026deg;, or sagittal vertical axis\u0026thinsp;\u0026gt;\u0026thinsp;5 cm. The exclusion criteria included any signs of deformity caused by other etiologies, history of spine surgery, spinal infection, tumor, and neuromuscular and connective tissue disorders. Informed consent was obtained from the enrolled participants before the study began. The workflow of this study is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eMorphological assessments\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe paraspinal muscle cross-sectional area (CSA) and fat infiltration rate (FI%) were obtained using ImageJ (v54) on T2-weighted MRI images. The CSAs and FI% of the bilateral paraspinal muscle at the L3 level were evaluated as previously reported[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In addition, the ratio of FI% (Ro FI%) between bilateral muscles was calculated \u003cem\u003e(left/right\u003c/em\u003e for DLS and \u003cem\u003econcave/convex\u003c/em\u003e for DS) to indicate the asymmetric distribution of FI. A total of 725 MRI scans were analyzed. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eparaspinal muscle endurance test\u003c/b\u003e\u003c/p\u003e\u003cp\u003eEndurance time was examined as previously reported. Briefly, patients were asked to lie in a prone position extend their back and maintain their maximal neck flexion until back fatigue. The best performance of the patients was used for further analysis. Patients with severe back pain were excluded in this study. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA.\u003c/p\u003e\u003cp\u003e\u003cb\u003emuscle strength examination\u003c/b\u003e\u003c/p\u003e\u003cp\u003eParaspinal muscle strength was measured using hand-held dynamometry (Micro FET3, Hoggan Health Industries, Inc.), as previously reported[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Briefly, the patients were asked to lay in a prone position and perform a back extension with maximum strength. The test was performed three times, and the maximum effort was used in future analysis. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRadiological parameters\u003c/b\u003e\u003c/p\u003e\u003cp\u003eStanding anteroposterior radiographs were used to measure coronal and sagittal parameters, including the Cobb angle, coronal balance, pelvic incidence, sacral slope, pelvic tilt, sagittal vertical axis, and thoracic lordosis using Surgimap software (V26). Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD.\u003c/p\u003e\u003cp\u003e\u003cb\u003eDetermination of paraspinal sarcopenia\u003c/b\u003e\u003c/p\u003e\u003cp\u003eParaspinal sarcopenia was defined as severe paraspinal muscle loss and poor strength with or without impaired muscle performance.\u003c/p\u003e\u003cp\u003eThresholds were obtained using upper or lower quartiles from the patients\u0026rsquo; baselines as previously reported[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Accordingly, each parameter was classified into \u0026ldquo;poor\u0026rdquo;, \u0026ldquo;fair\u0026rdquo;, and \u0026ldquo;good\u0026rdquo; status. The lower quartile of MVE and ET were regarded as poor muscle function and the upper quartile of MF FI% was as severe muscle loss. The upper and lower quartile of RoFI% was used to determine asymmetric muscle loss in DSD. Accordingly, thresholds of gender-specified paraspinal sarcopenia for non-scoliotic DLD patients and DSD were determined.\u003c/p\u003e\u003cp\u003e\u003cb\u003eThe characteristics of DSD patients with paraspinal sarcopenia\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTo emphasize the characteristics of DSD patients with paraspinal sarcopenia, the demographic and radiological data were compared patients with and without paraspinal sarcopenia. Clinical outcomes were evaluated by the patient-reported questionnaires including SRS-22 and SVA back pain score. Finally, the ROC was performed to test the predictability of paraspinal sarcopenia measurements on adverse clinical outcomes in DSD patients.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eAll statistic was conducted in GraphPad Prism (V9) or RStudio (V4.2.2). The continuous data were shown in mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D or median and interquartile range (IQR). The difference between groups was tested by unpaired student t-tests or one-way ANOVA coupled with Fisher\u0026rsquo;s least significant difference (LSD) post-hoc test.\u003c/p\u003e\u003cp\u003eThresholds were obtained using upper or lower quartiles from the patients\u0026rsquo; baselines as previously reported[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Accordingly, each parameter was classified into \u0026ldquo;poor\u0026rdquo;, \u0026ldquo;fair\u0026rdquo;, and \u0026ldquo;good\u0026rdquo; status. The area under the curve (AUC) of SDSS parameters was calculated to assess the predictability of measurements. AUC values of less than 0.7 were considered poor, 0.7 to 0.8 as acceptable, 0.8 to 0.9 as excellent, and greater than 0.9 as outstanding.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 342 patients were enrolled in the final analysis, among which 204 were DLS and 138 were DSD. The workflow of this study is illustrated in Fig. \u003cspan\u003e1\u003c/span\u003e. The baseline demographic and clinical characteristics of patients are listed in Table \u003cspan\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eMost patients were female in both DSD and DLS groups (M/F: 21/117 vs 48/156, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.06). There were no differences in age or BMI between the two groups. For the comorbidities, DSD patients showed a higher percentage of anemia (18.1% vs. 6.9%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and hypoproteinemia (9.4% vs. 2.5%, \u003cem\u003eP\u0026thinsp;=\u003c/em\u003e\u0026thinsp;0.08) compared to the DLS, while no differences were found in terms of diabetes or hypertension (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003cp\u003eExpectedly, radiological evaluations suggested DSD patients demonstrated severe sagittal misalignment, specifically the SVA of DLS was smaller compared to DSD (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating severe spinal malalignment in DSD (Table \u003cspan\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParaspinal muscle morphological comparison\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe CSAs of MF, ES, and total muscle were comparable between the two groups, but the weighted MF FI% (34.82\u0026thinsp;\u0026plusmn;\u0026thinsp;18.62 vs. 22.69\u0026thinsp;\u0026plusmn;\u0026thinsp;12.25, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) was higher in the DSD group compared to the DLS, indicating severe fatty replacement of paraspinal muscle in DSD. Expectedly, Ro FI% of paraspinal muscle was around 1 for DLS, but the ratio was higher in DSD (MF: 1.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.45 vs. 1.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; ES: 1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 vs. 0.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.025). Table \u003cspan\u003e3\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eThe measurements of patients\u0026rsquo; data were performed by two authors (A.K and M.W), and Intra- and inter-rater coefficients were good to excellent for CSA, MF FI%, and paraspinal muscle measurements (ICC\u0026thinsp;\u0026gt;\u0026thinsp;0.8) (Table \u003cspan\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParaspinal muscle functional evaluation and correlation analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe median paraspinal muscle strength was 119.4N (IQR 95.38-143.35N) in DLS and 92.50N (IQR 73.01-118.05N) in DSD. Paraspinal strength was higher in the DLS group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The paraspinal muscle performance (ET) was higher in DLS with a median ET of 31.28s (IQR 19.27-43.52s) while 21.17s (IQR 10.64-33.27s) for DSD (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Table\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDetermination of threshold value for paraspinal sarcopenia\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThreshold values were determined as previously described[\u003cspan\u003e24\u003c/span\u003e]. Accordingly, MF FI%\u0026gt;45% was defined as severe muscle mass loss, \u0026lt;\u0026thinsp;21% was good, and 21\u0026thinsp;~\u0026thinsp;27% was fair for female patients with DSD (Fig. \u003cspan\u003e3\u003c/span\u003eA). The MF FI%\u0026gt;32% was defined as severe muscle mass loss, \u0026lt;\u0026thinsp;16% was good, and 16\u0026thinsp;~\u0026thinsp;32% was fair for male patients with DSD (Supplementary Fig. 1A). The MF FI%\u0026gt;31% was severe, \u0026lt;\u0026thinsp;19% was good, and 19\u0026thinsp;~\u0026thinsp;31% was fair for female patients with DLS (Fig. \u003cspan\u003e3\u003c/span\u003eB). The MF FI%\u0026gt;25% was severe, \u0026lt;\u0026thinsp;15% was good, and 15\u0026thinsp;~\u0026thinsp;25% was fair for female patients with DLS. (Supplementary Fig. 1B).\u003c/p\u003e\n\u003cp\u003eFor paraspinal muscle strength, the MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N was defined as poor, \u0026gt;\u0026thinsp;115N was good, and 70N to 115N was fair for female patients with DSD (Fig. \u003cspan\u003e3\u003c/span\u003eC). The MVE\u0026thinsp;\u0026lt;\u0026thinsp;86N was poor, \u0026gt;\u0026thinsp;117N was good, and 117\u0026thinsp;~\u0026thinsp;115N was fair for male patients with DSD (Supplementary Fig. 1C). The MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N was poor, \u0026gt;\u0026thinsp;133N was good, and 90\u0026thinsp;~\u0026thinsp;133N was fair for female patients with DLS (Fig. \u003cspan\u003e3\u003c/span\u003eD); The MVE\u0026thinsp;\u0026lt;\u0026thinsp;107N was poor, \u0026gt;\u0026thinsp;143N was good, and 107N\u0026thinsp;~\u0026thinsp;143N was fair for female patients with DLS. (Supplementary Fig.\u0026nbsp;1D).\u003c/p\u003e\n\u003cp\u003eSimilarly, ET\u0026thinsp;\u0026lt;\u0026thinsp;7s were defined as poor, \u0026gt;\u0026thinsp;32s was good, and 7s\u0026thinsp;~\u0026thinsp;32s was fair for female patients with DSD. ET (Fig.\u0026nbsp;\u003cspan\u003e3\u003c/span\u003eE). The ET\u0026thinsp;\u0026lt;\u0026thinsp;6s were defined as poor, \u0026gt;\u0026thinsp;28s was good, and 6s\u0026thinsp;~\u0026thinsp;28s was fair for male patients with DSD (Supplementary Fig.\u0026nbsp;1E). The ET\u0026thinsp;\u0026lt;\u0026thinsp;15s were defined as poor, \u0026gt;\u0026thinsp;43s was good, and 15s\u0026thinsp;~\u0026thinsp;43s was fair for female patients with DLS (Fig.\u0026nbsp;\u003cspan\u003e3\u003c/span\u003eF). The ET\u0026thinsp;\u0026lt;\u0026thinsp;17s were defined as poor, \u0026gt;\u0026thinsp;47s was good, and 17s\u0026thinsp;~\u0026thinsp;47s was fair for male patients with DLS (Supplementary Fig.\u0026nbsp;1F).\u003c/p\u003e\n\u003cp\u003eTo assess the contribution of asymmetric muscle loss, an additional morphological parameter Ro FI% was assessed, and both upper and lower quintiles were calculated. The MF Ro FI%\u0026gt;1.3 or \u0026lt;\u0026thinsp;0.75 was defined as severe asymmetric, and 0.75 to 1.3 were fair. (Fig.\u0026nbsp;\u003cspan\u003e3\u003c/span\u003eG).\u003c/p\u003e\n\u003cp\u003eAccordingly, the threshold values for paraspinal sarcopenia in DSD were: MF FI%\u0026gt;45%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;7s for female; MF FI%\u0026gt;32%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;86N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;6s for male. The Threshold value for paraspinal sarcopenia in DLS were: MF FI%\u0026gt;19%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;15s for female; MF FI%\u0026gt;25%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;107N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;17s for males.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe predictive role of paraspinal sarcopenia in HRQoL in patients with DLD\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe AUC of paraspinal sarcopenia parameters in DSD patients for VAS back pain score was 0.868. The AUC of SDSS parameters for the SRS-22 score, a questionnaire to reflect spine deformity-related health quality impairs, was 0.887 (Fig. \u003cspan\u003e4\u003c/span\u003eA). These results indicated excellent predictability of SDSS parameters regarding poor clinical outcomes in DSD. A representative case of DSD patients with paraspinal sarcopenia suffering back pain and low SRS-22 cores (deformity-related questionnaires) was shown in (Fig. \u003cspan\u003e4\u003c/span\u003eB).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCharacteristics of DSD patients with paraspinal sarcopenia\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo highlight the Characteristics of DSD patients with paraspinal sarcopenia, the demographic, radiological, and clinical outcome measurements including SVA back pain score and SRS-22 (Total) were compared patients with and without paraspinal sarcopenia. DSD patients with paraspinal sarcopenia were commonly advanced in age (with \u003cem\u003evs.\u003c/em\u003e without, 63.6\u0026thinsp;\u0026plusmn;\u0026thinsp;6.4 vs 59.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.036), decreased lumbar lordosis (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.028) and with severe sagittal imbalance (with \u003cem\u003evs.\u003c/em\u003e without:103.84\u0026thinsp;\u0026plusmn;\u0026thinsp;34.26mm vs 76.75\u0026thinsp;\u0026plusmn;\u0026thinsp;42.81mm, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Table \u003cspan\u003e5\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eAccordingly, an algorithm for screening paraspinal sarcopenia for DLD patients (specifically for non-spine deformity and deformity patients) was proposed. Figure \u003cspan\u003e5\u003c/span\u003e.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eParaspinal sarcopenia is widely recognized as a contributing factor in DLD. However, its definition remains controversial, and comprehensive diagnostic threshold values have not been determined. In this study, paraspinal sarcopenia was defined as the presence of both severe paraspinal muscle mass loss and dysfunction. Diagnostic thresholds were obtained using patients\u0026rsquo; morphological and functional data. The sex-specific and disease-tailored threshold values for paraspinal sarcopenia in patients with DSD were: MF FI%\u0026gt;45%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;7.1s for female; MF FI%\u0026gt;31%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;86N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;5.9s for male. The Threshold value for paraspinal sarcopenia in DLS were: MF FI%\u0026gt;19.1%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;15s for females; MF FI%\u0026gt;25%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;106N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;17s for males. These thresholds demonstrated excellent predictive value for assessing HRQoL. This study provides disease-specific thresholds for paraspinal sarcopenia that correlate with reduced HRQoL, offering potential utility in identifying patients with compromised muscle health and informing intervention strategies to enhance paraspinal muscle function and HRQoL.\u003c/p\u003e\u003cp\u003eIdentifying driving factors is crucial for addressing the adverse outcomes of DLD and improving HRQoL. Paraspinal sarcopenia has emerged as a significant influencing factor and therapeutic target in patients with DLD. However, inconsistent findings across the literature may be attributed to variations in the definition and diagnostic methods used[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Many previous studies defined paraspinal sarcopenia as a localized manifestation of systemic sarcopenia and diagnosed it based on appendicular muscle mass and function. Consequently, reported prevalence rates range from 17\u0026ndash;34% in DLS and 46\u0026ndash;59% in DSD cases[\u003cspan additionalcitationids=\"CR26 CR27\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003csup\u003e,\u003c/sup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].Increasing evidence, however, suggests that paraspinal sarcopenia represents site-specific muscle loss distinct from systemic sarcopenia. Sch\u0026uml;onnagel \u003cem\u003eet al\u003c/em\u003e.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] found that paraspinal sarcopenia is different from systemic sarcopenia in a relatively small sample of non-deformed DLD. Thus, diagnosing paraspinal sarcopenia using criteria intended for systemic sarcopenia may result in misclassification. It is therefore critical to establish a clear and specific definition to resolve discrepancies in research findings, standardize diagnostic protocols, and develop targeted interventions to improve spinal muscle health and HRQoL in patients with DLD.\u003c/p\u003e\u003cp\u003eDetermining precise diagnostic thresholds is essential for effectively identifying paraspinal sarcopenia in patients with DLD. The current consensus defines sarcopenia as the coexistence of muscle mass loss and dysfunction[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Kim et al. proposed a protocol to assess paraspinal sarcopenia[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]; however, their method was based on community-dwelling cohorts who may differ in presentation from patients with DLD, and it requires an isokinetic dynamometer that is not commonly available in clinical practice. Sch\u0026uml;onnagel et al. defined severe paraspinal muscle atrophy (indicated by MF FI\u0026thinsp;\u0026gt;\u0026thinsp;50%) as spinal-specific sarcopenia. However, this value reflects only muscle mass loss and does not account for muscle function. Moreover, prior studies reported MF FI% at the L3 level ranging from 22\u0026ndash;35% in DLS[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. In addition, paraspinal sarcopenia exhibits sex-based patterns in patients with DLD[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Therefore, using a cutoff of MF FI% \u0026gt;50% may be arbitrary and yield low diagnostic accuracy in DLS[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. In the present study, we determined threshold for paraspinal muscle were MF FI%\u0026gt;19%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N, ET\u0026thinsp;\u0026lt;\u0026thinsp;15s for female and MF FI%\u0026gt;25%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;107N, ET\u0026thinsp;\u0026lt;\u0026thinsp;17s for males. Although changes in muscle strength have been reported in DLS, methodologies vary in the literature. Han et al.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] enrolled 303 patients with DLS undergoing spinal fusion and categorized ET\u0026thinsp;\u0026lt;\u0026thinsp;10 s as poor and ET\u0026thinsp;\u0026gt;\u0026thinsp;60 s as good, differing from our findings. This discrepancy may result from differences in study populations. We included both outpatients and inpatients, whereas their study included only inpatients.\u003c/p\u003e\u003cp\u003eFurthermore, to our knowledge, we were the first to determine threshold values of paraspinal sarcopenia for DSD. The Ro FI%\u0026gt;1.3 or \u0026lt;\u0026thinsp;0.75 and MF FI\u0026thinsp;\u0026gt;\u0026thinsp;45% and \u0026gt;\u0026thinsp;31%were proposed as thresholds for severe muscle loss, ET\u0026thinsp;\u0026lt;\u0026thinsp;7s and \u0026lt;\u0026thinsp;6s as poor muscle performance, MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N and \u0026lt;\u0026thinsp;86N as poor muscle function for female and male DSD patients, respectively. DSD is a multifactorial disease characterized by paraspinal muscle distortion that differs from that in DLS[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Several studies have reported more severe fatty infiltration and reduced muscle function in patients with DSD compared to those with DLS, consistent with our findings[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Additionally, bilateral paraspinal muscle in DSD often shows asymmetric degeneration, possibly resulting in varying degrees of sarcopenia. Previous studies have reported an average MVE of 85N in severe DSD; our findings were similar, with an average MVE of 86.9 N. However, no prior studies have determined a cutoff for poor muscle function in DSD. To characterize asymmetric muscle loss, we evaluated an additional parameter, Ro FI%, which had not been previously reported. Our findings help define reference values for diagnosing paraspinal sarcopenia and offer new tools for screening muscle dysfunction in patients with DSD. External validation is still necessary in future studies.\u003c/p\u003e\u003cp\u003eWe also explored characteristics of DSD patients with paraspinal sarcopenia. These patients tended to be older, have higher BMI, and exhibit poorer nutritional status (evidenced by anemia and hyperemia), suggesting more advanced degeneration. Patients with paraspinal sarcopenia also reported more severe HRQoL impairment. Diagnostic markers of paraspinal sarcopenia demonstrated strong predictive value for low back pain and SRS-22 scores, with AUC values of 0.81 and 0.863. Zhang et al.[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] reported that poor nutritional status is associated with lower HRQoL in patients with DSD. Advanced spinal degeneration and poor nutrition may underlie the impaired HRQoL in these patients. Thus, the proposed cutoff values not only effectively screen for paraspinal sarcopenia in patients with DSD but also identify those at risk for poor HRQoL. Nutritional support has been recognized as a key strategy for sarcopenia prevention[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. However, given the significant differences between paraspinal and systemic sarcopenia, therapeutic approaches\u0026mdash;such as nutritional intervention\u0026mdash;should be tailored specifically for patients with paraspinal sarcopenia in DSD.\u003c/p\u003e\u003cp\u003eThe strengths of this study include the establishment of clear definitions and diagnostic thresholds for paraspinal sarcopenia in DLD, and the exploration of its clinical significance in the physical well-being of aged patients with DLD. However, this study has several limitations. First, it is a single-center study with a relatively small sample size; multicenter studies are warranted. Second, paraspinal muscle functional indices may vary across ethnicities, suggesting that ethnicity-specific thresholds should be developed. Third, due to limited sample size\u0026mdash;particularly the small number of male participants\u0026mdash;sex-specific thresholds may be underpowered. Finally, semi-quantitative methods were used to evaluate muscle morphology, and the relationship between morphology and function is not necessarily linear.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, paraspinal sarcopenia was defined as both paraspinal muscle mass and function loss in this study, with gender specified and distinct thresholds for DLD patients. We were the first to determine the threshold values for diagnosing paraspinal sarcopenia for DLD patients with or without spinal deformity using basic morphological and functional data. The threshold values for paraspinal sarcopenia in DSD were: MF FI%\u0026gt;45%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;7.1s for female; MF FI%\u0026gt;31%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;86N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;5.9s for male. The Threshold value for paraspinal sarcopenia in DLS were: MF FI%\u0026gt;19.1%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;15s for females; MF FI%\u0026gt;25%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;106N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;17s for males. Finally, we found that DSD patients with paraspinal sarcopenia had a more advanced degenerative status and malnutrition, which correlated with poor HRQoL. The findings of the present study provided a practical tool for screening paraspinal sarcopenia in DLD patients and may aid in designing personalized patient care for the treatment of paraspinal sarcopenia.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA.K. and M.W. conducted the measurements, analysis, and wrote the main manuscript.J.L. and Z.H. interpreted the acquired data.Y.X. and J.H. measured specific aspects of paraspinal muscle strength and endurance.Q.L. prepared Figures 1 and 5.Z.Z. and Y.Q. conceptualized and supervised the project.Z.L. provided critical revisions to the manuscript for important intellectual content, supervised the project, and offered financial support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eTieland M, Trouwborst I, Clark BC (2018) Skeletal muscle performance and ageing. 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J Hepatol 75(1):S147\u0026ndash;S162. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhep.2021.01.025\u003c/span\u003e\u003cspan address=\"10.1016/j.jhep.2021.01.025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1:\u0026nbsp;\u003c/strong\u003eComparison of demographic data, systemic and paraspinal sarcopenia measurements in DLS and DSD patients\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"552\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eDSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eDLS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cem\u003eP-\u003c/em\u003evalue\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eDemographic information\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; No. of participants\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e138\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e204\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Age (y)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e62.0\u0026plusmn;7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e61.4\u0026plusmn;7.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.407\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Gender (M/F)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e21/117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e48/156\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cem\u003e0.060\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;BMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e25.7\u0026plusmn;4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e25.3\u0026plusmn;4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cem\u003e0.342\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Anemia (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e25 (18.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e14(6.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Hypoproteinemia (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e13 (9.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e5 (2.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.005\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Diabetes (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e20 (14.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e24 (11.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.460\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Hypertension (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e29 (21.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e59 (28.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.101\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote\u003c/em\u003e: Data are presented as counts and percentages for categorical variables and mean \u0026plusmn; standard deviation or median [first quartile, third quartile] for continuous variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAbbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; BMI, body mass index.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u0026nbsp;\u003c/strong\u003eRadiographic data comparison of enrolled degenerative spinal deformity and degenerative lumbar stenosis patients\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"616\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003eDSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003eDLS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eRadiological parameters\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Cobb angle (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e35.6\u0026plusmn;8.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e/\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e/\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; SS (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e19.9\u0026plusmn;12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e31.9\u0026plusmn;7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; PT (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e22.2\u0026plusmn;13.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e17.4\u0026plusmn;7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.021\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; PI (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e42.3\u0026plusmn;12.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e49.7\u0026plusmn;8.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.008\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; LL (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e21.1\u0026plusmn;28.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e41.9\u0026plusmn;12.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; TK (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e29.2\u0026plusmn;25.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e32.7\u0026plusmn;10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e0.518\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 207px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; SVA (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e76.6\u0026plusmn;66.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e29.5\u0026plusmn;15.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 154px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote\u003c/em\u003e: Data are presented as counts and percentages for categorical variables and mean \u0026plusmn; standard deviation for continuous variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3:\u003c/strong\u003e Comparison of demographic data, systemic and paraspinal sarcopenia measurements in DLS and DSD patients\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"552\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eDSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eDLS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cem\u003eP-\u003c/em\u003evalue\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eMuscle function parameters\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;ET (s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e17.6 [6.5, 30.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e21.2 [8.1, 39.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.026\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;MVE (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e86.9 [67.5, 113.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e106.6 [77.4, 134.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.013\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eMorphological assessments\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Weighted CSA (MF)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e78.7\u0026plusmn;43.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e82.3\u0026plusmn;32.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.523\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Weighted CSA (ES)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e136.2\u0026plusmn;58.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e142.8\u0026plusmn;47.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.427\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Weighted FI% (MF)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e34.8\u0026plusmn;18.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e22.6\u0026plusmn;12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Weighted FI% (ES)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e27.4\u0026plusmn;17.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e18.3\u0026plusmn;10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Ro FI%(MF)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.3\u0026plusmn;0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.0\u0026plusmn;0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 187px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Ro FI%(ES)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.1\u0026plusmn;0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.0\u0026plusmn;0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e0.257\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote\u003c/em\u003e: Data are presented as counts and percentages for categorical variables and mean \u0026plusmn; standard deviation or median [first quartile, third quartile] for continuous variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAbbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; ET, endurance time; MVE, maximal voluntary exert force; MF, multifidus muscle: ES, erector spinae. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4:\u003c/strong\u003e Intra- and inter-rater reliability test for measured parameters\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003eIntra-rater coefficient\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003eInter-rater coefficient\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 554px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eRadiological parameters\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eCobb angle (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eSS (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003ePT (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003ePI (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eLL (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eTK (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eSVA (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eMuscle function parameters\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eET (s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003eMVE (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eMorphological assessments\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;CSA (cm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 185px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;FI%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 184px;\"\u003e\n \u003cp\u003e0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote\u003c/em\u003e: Abbreviations: SS, sacral slope; PT, pelvic tilt; PI, pelvic index; LL, lumbar lordosis; TK, thoracic kyphosis; SVA, sagittal vertical index; HGS, hand grip strength; ET, endurance time; MVE, maximal voluntary exert force; CSA, cross-sectional area; FI%, fat infiltration rate.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5\u0026nbsp;\u003c/strong\u003eThe comparison of basic characteristics and clinical outcomes of patients with SDSS and non-SDSS without systemic sarcopenia\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"560\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eSDSS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eNon-SDSS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eNo. of participants\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e288\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eAge (y)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e63.6\u0026plusmn;6.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e59.5\u0026plusmn;5.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.036\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eNo. male/female\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e12/42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e57/231\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e/\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e25.8\u0026plusmn;5.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e25.2\u0026plusmn;4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e0.357\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eAnemia (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e19 (35.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e20 (6.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eHypoproteinemia (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e7(13.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e11 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eDiabetes (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e18 (33.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e26 (9.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eHypertension (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e15 (27.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e73 (25.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e0.708\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eVAS back pain score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e5.8\u0026plusmn;2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e5.0\u0026plusmn;2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eSS (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e21.5\u0026plusmn;10.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e27.3\u0026plusmn;8.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.006\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003ePT (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e34.4\u0026plusmn;15.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e22.8\u0026plusmn;12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003ePI (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e55.2\u0026plusmn;12.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e49.5\u0026plusmn;10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e0.427\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eLL (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e19.6\u0026plusmn;17.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e38.8\u0026plusmn;14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.028\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eTK (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e29.4\u0026plusmn;18.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e33.2\u0026plusmn;18.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e0.874\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003eSVA (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e83.8\u0026plusmn;44.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e34.75\u0026plusmn;22.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 140px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote\u003c/em\u003e: Data are presented as counts and percentages for categorical variables and mean \u0026plusmn; standard deviation for continuous variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAbbreviations: DSD, degenerative spinal deformity; DLS, degenerative lumbar stenosis; BMI, body mass index; SS, sacral slope; PT, pelvic tilt; PI, pelvic index; LL, lumbar lordosis; TK, thoracic kyphosis; SVA, sagittal vertical index.\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Paraspinal sarcopenia, Degenerative spinal deformity, Degenerative lumbar diseases, Fat infiltration","lastPublishedDoi":"10.21203/rs.3.rs-7085436/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7085436/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction\u003c/h2\u003e\u003cp\u003eEmerging evidence shows that paraspinal sarcopenia is closely linked to adverse clinical outcomes in degenerative lumbar diseases (DLDs), including degenerative spinal deformity (DSD) and degenerative lumbar stenosis (DLS). However, its definition remains controversial, and precise diagnostic thresholds have yet to be established. Moreover, diagnostic criteria for paraspinal sarcopenia may differ across these DLD subtypes.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003ePatients with DLD were prospectively enrolled. Clinical outcomes included the SRS-22 and visual analog scale scores (VAS) for back pain and leg pain. Fat infiltration rate (FI%) of multifidus muscle was used to assess muscle mass loss. Endurance time (ET) and evaluating muscle maximal exert (MVE) were evaluated to determine paraspinal muscle performance and strength. Threshold values were determined by obtaining the upper or lower quartiles of measured data. Further, distinct and sex-specified threshold values for paraspinal sarcopenia were specifically established for each group. Furthermore, the predictive accuracy of paraspinal sarcopenia measurements for quality of life was assessed by calculating the area under the curve (AUC).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eA total of 342 patients enrolled in this study. The threshold values for paraspinal sarcopenia in DSD were: MF FI%\u0026gt;45%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;70N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;7.1s for female; MF FI%\u0026gt;31%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;86N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;5.9s for male. The Threshold value for paraspinal sarcopenia in DLS were: MF FI%\u0026gt;19.1%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;90N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;15s for females; MF FI%\u0026gt;25%, MVE\u0026thinsp;\u0026lt;\u0026thinsp;106N, and ET\u0026thinsp;\u0026lt;\u0026thinsp;17s for males. DSD patients with paraspinal sarcopenia had impaired HRQoL (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004). The thresholds of paraspinal sarcopenia in DSD for worse back pain and SRS-22 scores were good with an AUC of 0.869 and 0.887.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eThreshold values were obtained using paraspinal muscle data from patients with DSD and DLS, respectively. DSD patients with paraspinal sarcopenia exhibited more advanced degenerative spinal changes and poorer quality of life. These findings provide reference values for identifying patients with paraspinal sarcopenia.\u003c/p\u003e","manuscriptTitle":"Defining Threshold values of Paraspinal Sarcopenia in Patients with Degenerative Lumbar Diseases","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-23 05:41:15","doi":"10.21203/rs.3.rs-7085436/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"472507c5-5bd8-49e8-ba2a-d2c37e4f1db5","owner":[],"postedDate":"July 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-23T05:41:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-23 05:41:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7085436","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7085436","identity":"rs-7085436","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}