Affiliations: [a] Department of Orthopaedics, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China | [b] Department for Combat Casualty Care Training, Training Base for Army Health Care, Army Medical University (Third Military Medical University), Chongqing, China | [c] Department of Orthopaedics, The Hospital of Eighty-third Army, Xinxiang Medical College, Xinxiang, Henan, China
Correspondence:
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Corresponding author: Fei Luo, Southwest Hospital, Army Medical University (Third Military Medical University), No. 30 Gaotanyan Street, Shapingba, Chongqing 400038, China. E-mail: luofeispine@126.com.
Note: [1] Can Chen and Sen Yang contributed equally to this work and should be considered co-first authors.
Abstract: BACKGROUND: The incidence rate of degenerative spinal deformity (DSD) has gradually increased in the elderly. Currently, the relationship between the functional status of trunk muscle and the spinal-pelvic parameters of DSD patients remains unclear. OBJECTIVE: This paper aims to explore the relationship between the two factors and provide new clues for exploring the mechanism of the occurrence and development of DSD. METHODS: A total of 41 DSD patients treated in our hospital (DSD group) and 35 healthy volunteers (control group) were selected. Muscle strength was evaluated using an IsoMed-2000 isokinetic dynamometer, and the trunk flexor and extensor peak torque (PT) of subjects was measured at a low, medium, and high angular velocity of 30∘/s, 60∘/s, and 120∘/s, respectively. Hand grip strength (HGS) was assessed using an electronic grip dynamometer and Surgimap software was used to measure the spinal-pelvic parameters, including the sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence rate (PI), and PI-LL, and the relationship between trunk muscle function and various parameters was analyzed. RESULTS: Under the three angular velocities, the flexor and extensor PT values in the DSD group were lower than those in the control group, and only the extensor PT showed a statistically significant difference (P< 0.05). There was no significant difference in HGS between the two groups (P> 0.05). In the DSD group, the extensor PT at 30∘/s was significantly negatively correlated with SVA (P< 0.05). At 60∘/s and 120∘/s, the extensor PT was significantly negatively correlated with SVA and PT (P< 0.05). CONCLUSION: Trunk extensor strength is significantly lower in DSD patients than in normal controls. The decline in trunk extensor strength in DSD patients is a type of local muscle dysfunction more closely related to the deformity, which is likely involved in the compensatory mechanism of DSD and may reflect the overall imbalance of the trunk.
