To explore the diagnostic and evaluation value of musculoskeletal ultrasound elastography in the standing position for nonspecific low back pain (NLBP).

A total of 16 patients with NLBP, who had not received treatment within two weeks prior to enrollment, were recruited as the observation group from Shanghai Ruijin Rehabilitation Hospital between June 2024 and June 2025, and 8 healthy people in the same period were selected as the control group. Before treatment or during physical examination, basic data such as gender, age, and body mass index (BMI) were collected, and musculoskeletal ultrasound related indicators (thickness of transversus abdominis, elastic modulus of transversus abdominis, thickness of lumboiliocostoid muscle, elastic modulus of lumboiliocostoid muscle) were measured in standing position. At the same time, the visual analogue scale (VAS) was used to evaluate the degree of pain in the observation group. R 4.5.2 software was used for statistical analysis and diagnostic modeling, and the receiver operating characteristic (ROC) curve was drawn. The area under curve (AUC), sensitivity, specificity and cut-off value of each diagnostic model were calculated, and the diagnostic efficacy of each model was compared.

There was no significant difference in gender, age, and BMI between the observation group and the control group (P>0.05). There was no significant difference in the thickness of transversus abdominis and lumboiliocostalis between the observation group and the control group (P>0.05). The elastic modulus of transverse abdominis in the observation group was significantly lower than that in the control group, and the elastic modulus of lumboiliocostalis in the observation group was significantly higher than that in the control group, and the differences were statistically significant (P<0.05). Pearson correlation analysis showed that among the diagnostic models, the quadratic power model of elastic modulus ratio (the ratio between the elastic modulus of transverse abdominis muscle and the elastic modulus of lumboiliocostoid muscle) had the best diagnostic performance, with an AUC of 1.000, followed by the elastic modulus of lumboiliocostoid muscle and elastic modulus ratio model, with AUC of 0.852 and 0.812, respectively. In addition, the VAS score of the observation group was positively correlated with the elastic modulus of the lumbar iliocostalis muscle in the standing position (P<0.001), and the VAS score of the observation group was negatively correlated with the ratio of elastic modulus in the standing position (P<0.001). In the control group, the ratio of elastic modulus in standing position was between 1.22 and 1.90, while in the observation group, the ratio was between 0.50 and 1.22 or >1.90.

The ratio of the elastic modulus of the transverse abdominis muscle to that of the lumboiliocostoid muscle measured by ultrasound in standing position can be used as an objective parameter, which is correlated with the subjective VAS score of NLBP patients, suggesting that the evaluation of muscle and bone elastography in standing position is expected to be one of the objective evaluation methods for NLBP patients, and provide quantitative basis for early diagnosis, efficacy evaluation and rehabilitation plan development.