Obesity is an important risk factor linked to the incidence of both neck pain (NP) and intervertebral disc degeneration (IVDD). Subcutaneous fat tissue thickness (SFTT) has been proposed as a more effective biomarker than body mass index (BMI) when gauging body fat levels. This study was thus designed to explore the optimal SFTT cutoff value for differentiating between NP patients and asymptomatic individuals by using the subcutaneous fat index (SFI). Magnetic resonance imaging (MRI) records from NP patients and asymptomatic controls were compared to evaluate IVDD, the fatty infiltration of the paravertebral muscles, and Modic changes. Cervical SFTT was also assessed at multiple levels. SFTT at the C3 level was found to be significantly associated with NP, with respective optimal cutoff values of 9.64 mm and 8.21 mm for females and males. Females in this study cohort more frequently exhibited spine deterioration with an SFI > 9.64 mm as compared to males with an SFI > 8.21 mm. Cervical SFTT is strongly correlated with the degree of disc degeneration. IVDD, Modic changes, and fatty infiltration in the paravertebral muscles were all more prevalent among both males and females exhibiting SFTT at the C3 level that was above the defined cutoff value.

肌肉退变是人口老龄化过程的主要特征之一，是老龄化社会的一个常见问题。2010年，欧洲肌少症工作组（EWGSOP）首先发表了肌少症共识，定义肌少症为一种增龄相关的肌肉量减少、肌肉力量下降和（或）躯体功能减退的老年综合征 [1] 。长久以来，脊柱椎旁肌肉维持脊柱稳定性的作用一直得到认可。腰椎椎旁肌肉如多裂肌和竖脊肌的特征与多种脊柱疾病的病理过程相匹配，如下腰痛、腰椎间盘突出症、腰椎活脱及脊柱畸形等 [2-5] 。

OBJECTIVE:To analyze the relationship between gender, age, and the degree of lumbar degenerative disease. METHODS:290 patients with Lumbar spinal stenosis and sciatica were analyzed. Sixty patients without sciatica were collected in the control group. Patient demography including age, gender, body mass index (BMI), serum calcium, and triglyceride level was acquired. The cross-sectional area (CSA) and percentage of fat infiltration area (Intermuscular adipose tissue (IMat%) of paraspinal muscles at the L4-5 level were measured using MRI imaging. The patients were divided into five age groups: A (18-30 years old), B (31-40 years old), C (41-50 years old), D (51-60 years old), and E (> 60 years old). Analysis of variance (ANOVA) and LSD was used to analyze differences among subgroups. Student's t-test was used to compare MCSA and fat CSA in the two groups. P < 0.05 was statistically significant. RESULTS:The paraspinal muscle CSA (MCSA) was significantly smaller in women (P < 0.05). Older age was associated with less MCSA and greater fatty infiltration in erector spinae and multifidus (MF) muscle (P < 0.05). Serum calcium and BMI were positively correlated with CSA of erector spinae muscle (P < 0.05), but not with muscle fat infiltration (P > 0.05). Although there was no significant difference in MCSA between the two groups, the fat infiltration (IMat%) in the disease group was significantly higher than in the control group (p < 0.05). CONCLUSION:Lumbar degenerative diseases caused the degeneration of the paravertebral muscles, which mainly resulted in increased intramuscular fat infiltration, rather than changes in the overall MCSA.