To investigate the correlation between the three-dimensional morphological parameters of cervical paraspinal muscles and the prognosis of posterior cervical decompression and lateral mass screw fixation (PCL+LSF) for patients with multilevel cervical spondylotic myelopathy.

The clinical data of 162 patients with multilevel cervical spondylotic myelopathy who had undergone PCL+LSF from June 2019 to June 2021 was retrospectively analyzed. They were divided into two groups based on the Neck Disability Index at (24±6) months follow-up after surgery. The general and imaging data of the two groups of patients were compared and analyzed, Three dimensional reconstruction of the cervical paraspinal muscles was performed to evaluate the relative volume and fatty infiltration rate of the cervical paraspinal muscles.

No statistically significant differences between the two groups were noted in terms of gender, age, BMI, surgical time, JOA score and intraoperative bleeding. The relative volume of the levator scapulae muscle in the residual neck and shoulder pain group is smaller [(9.90±3.15) vs (8.36±2.35), t=3.510, P=0.001], and the fat infiltration rate is higher [(31.31±8.45) vs (40.55±11.52), t=5.819, P<0.001]; The relative volume of the sternocleidomastoid muscle in the residual neck and shoulder pain group is smaller [(6.57±1.73) vs (5.89±2.14), t=2.233, P=0.027], and the fat infiltration rate is higher [(11.86±5.63) vs (13.74±5.53), t=1.084, P=0.028]; The relative volume of the splenius capitis muscle in the residual neck and shoulder pain group is smaller [(26.33±7.39) vs (23.76±6.03), t=2.424, P=0.017], and the fat infiltration rate is higher [(13.05±4.09) vs (14.82±4.95), t=2.490, P=0.014]; The relative volume of the trapezius muscle in the residual neck and shoulder pain group is smaller [(25.66±7.38) vs (23.19±5.95), t=2.351, P=0.020], and the fat infiltration rate is higher [(6.09±1.91) vs (7.28±4.01), t=2.406, P=0.018]. The differences are statistically significant.

Reduced relative volume and increased fatty infiltration of the cervical multifidus, semispinalis cervicis, semispinalis capitis and splenius capitis are associated with poor relief of neck and shoulder pain after PCL combined with LSF for multilevel cervical myelopathy.