Study Design.: A retrospective, cross-sectional cohort study. Objective.: This study aimed to investigate the association between paraspinal muscle parameters and single-segment degenerative lumbar spondylolisthesis (DLS). Summary of Background Data.: The relationship between lumbar paraspinal muscle morphology and single-segment DLS remains unclear. Methods.: A retrospective review was conducted on 115 patients with L4/5 single-segment DLS and 105 subjects without DLS. Two independent investigators assessed the relative cross-sectional area and fat infiltration rate of the multifidus, erector spinae, and psoas major at L3/4, L4/5, and L5/S1 levels, comparing these measurements between the 2 groups. In addition, binary logistic regression analysis was performed with DLS as the dependent variable to analyze the relative cross-sectional area and fat infiltration rate of different paraspinal muscles. Within the DLS group, the correlation between paraspinal muscle characteristics and the anteroposterior diameter of the spinal canal was examined. Results.: The fat infiltration rate of multifidus, erector spinae, and psoas major was higher in the DLS group than in the control group, whereas the relative cross-sectional area of multifidus and psoas major was lower in the DLS group. Binary logistic regression analysis revealed a significant correlation between the fat infiltration rate of multifidus and psoas major and DLS. The relative cross-sectional area of multifidus and erector spinae was significantly smaller below the affected segment in the DLS group compared with the control group. A significant positive correlation was observed between the relative cross-sectional area of multifidus and erector spinae and the anteroposterior diameter of the spinal canal. Conclusion.: There is a close association between paraspinal muscle degeneration and single-segment DLS, with an increased relative cross-sectional area of the multifidus and psoas major possibly being risk factors for single-segment DLS. The restoration or enhancement of paraspinal muscle function could potentially serve as a pivotal target for the prevention and treatment of single-segment DLS. Level of Evidence.: Level III.

Background: Rotator cuff-related shoulder pain (RCRSP) is the most common cause of shoulder disorders. In China, manipulation has been used extensively for the treatment of patients with RCRSP. However, high-quality clinical evidence to support the therapeutic effect of manipulation is still limited. Methods: A multicenter, participant-, outcome assessor-, and data analyst-blinded, randomized, placebo-controlled trial will be conducted. A total of 280 participants with RCRSP will be recruited from three hospitals and randomly assigned to a five-step shoulder manipulation (FSM) group or a sham manipulation (SM) group. Each group will receive four weekly treatment sessions, with all participants performing exercises at home for 12 weeks. Assessments, namely the Constant–Murley score, visual analog scale, range of motion, and 36-Item Short Form Survey, will be made at baseline, 4, 12, 18, and 24 weeks. Adverse events during the study will also be recorded. Discussion: This is a pragmatic clinical trial to evaluate the efficacy and safety of FSM in patients with RCRSP. The findings of this study will provide worthy clinical evidence for manual therapy for RCRSP. Trial registration: China Registered Clinical Trial Registration Center ChiCTR2000037577. Registered on 29 August 2020.