Degeneration of Cervical Multifidus Muscles Negatively Affects Physical Activity-related Quality of Life After Laminoplasty for Degenerative Cervical Myelopathy.

Study design: A retrospective cohort study.

Objective: The study aimed to investigate the related factors affecting physical activity-related quality of life (QOL) after 2 years of cervical laminoplasty for degenerative cervical myelopathy (DCM), focusing on the degree of preoperative degeneration of the cervical multifidus muscles.

Summary of background data: The association between paraspinal muscle degeneration and clinical outcomes after spinal surgery is being investigated. The effect of preoperative degeneration of the cervical multifidus muscles in patients undergoing cervical laminoplasty is ambiguous.

Methods: Patients who underwent laminoplasty for DCM and followed up for more than 2 years were reviewed. To evaluate physical QOL, the physical component summary (PCS) of the 36-Item Short-Form Health Survey (SF-36) was recorded at 2 years postoperatively. The degree of preoperative degeneration in the multifidus muscles at the C4 and C7 levels on axial T2-weighted magnetic resonance imaging (MRI) was categorized according to the Goutallier grading system. The correlation between 2-year postoperative PCS and each preoperative clinical outcome, radiographic parameter, and MRI finding, including Goutallier classification, was analyzed. Variables with a P value <0.10 in univariate analysis were included in multiple linear regression analysis.

Results: In total, 106 consecutive patients were included. The 2-year postoperative PCS demonstrated significant correlation with age ( R =-0.358, P =0.002), preoperative JOA score ( R =0.286, P =0.021), preoperative PCS ( R =0.603, P <0.001), C2-C7 lordotic angle ( R =-0.284, P =0.017), stenosis severity ( R =-0.271, P =0.019), and Goutallier classification at the C7 level ( R =-0.268, P =0.021). In multiple linear regression analysis, sex (β=-0.334, P =0.002), age (β=-0.299, P =0.013), preoperative PCS (β=0.356, P =0.009), and Goutallier classification at the C7 level (β=-0.280, P =0.018) were significantly related to 2-year postoperative PCS.

Conclusions: Increased degeneration of the multifidus muscle at the C7 level negatively affected physical activity-related QOL postoperatively. These results may guide spine surgeons in predicting physical activity-related QOL in patients with DCM after laminoplasty.

Level of evidence: Level III.