Adolescent Idiopathic Scoliosis (AIS) is a complex three-dimensional spinal deformity with onset in adolescents between the ages of 10 and 18 years, characterized by coronal curvature, sagittal imbalance and horizontal rotation of the spine. The incidence of AIS is 1-4% globally, with more females than males, and it is a common, frequent and difficult-to-treat disease that seriously jeopardizes the physical and mental health of adolescents.

Previous studies have found significant changes in the morphologic structure and physiologic characteristics of the paraspinal muscles in patients with AIS, including muscle fiber distribution, muscle contraction and relaxation capacity, the convex side of the AIS curve exhibits a higher level of electromyographic activity, and asymmetric changes in the paraspinal muscles are highly correlated with progression of scoliosis. The current single-electrode sEMG technique extracts limited muscle activity signals and is susceptible to interference from random noise. Compared with the single-electrode sEMG technique, HD-sEMG can provide rich spatiotemporal information on paraspinal muscle activity, so it is necessary to use a wide and closely spaced electrode array for signal acquisition to obtain more accurate and detailed characteristics of paraspinal muscle activity.

In summary, this study used high-density surface electromyography to collect muscle parameters of the paraspinal muscles on the concave and convex sides of AIS patients and compared them with those of healthy people to comprehensively summarize the characteristics of their paraspinal muscles, so as to provide scientific basis for the subsequent development of precise treatment plans and improvement of clinical efficacy.

Paravertebral muscle EMG signals were acquired from AIS patients and healthy controls under the BST test paradigm.

Acquisition site: paravertebral muscle at the L1-L3 level, with the electrode sheet placed 1.5 cm adjacent to the spinous process.

（Biering-Sorensen test,BST）：The subject was lying prone on the bed, with the upper half of the body poking out of the bed, the anterior superior iliac spine located at the edge of the bed, both lower limbs partially immobilized on the bed with straps, both hands crossed in front of the chest grasping the contralateral shoulder and tightly pressed against the chest wall, and the torso was suspended in the air and parallel to the floor, and the patient stopped the test when he/she maintained this position for 90s.

Observation indicators:

1, the average change (mean) characteristics of each channel signal, including the 32 channels of the root mean square value （RMS）, mean power frequncy（MPF）, fractal dimension（FD）,Slope sign change(SSC), a total of 4 types of indicators-reflecting the strength and fatigue of muscle contractions..

Inclusion Criteria:

• Patients with a diagnosis of AIS
• Any gender, age 10-18 years old
• Signed informed consent and able to cooperate with follow-up
• Ability to cooperate with electromyography examination and evaluation, and to perform measurements of relevant indexes.

Exclusion Criteria:

• Subjects with spine-related diseases such as Marfan's syndrome
• Subjects with previous spine-related diseases such as ankylosing spondylitis, spinal neurofibroma, spinal tuberculosis, spinal trauma, etc
• Subjects with comorbid serious medical diseases and patients with psychiatric disorders
• Subjects with ECOG scores of >2, which may have an effect on the results of the study

AIS patients and healthy control populations