The purpose of this study is to compare and examine the impact of the number of fused vertebrae on sit-to-stand movements in patients who have undergone spinal fusion surgery, utilizing a tri-axial accelerometer for analysis.
This study included patients who underwent lumbar interbody fusion for degenerative lumbar disease (SF group: 1–4 vertebrae fused) or spinal corrective fusion for adult spinal deformity (LF group: 5 or more vertebrae fused). Exclusion criteria included those within three months post-surgery, wearing a trunk orthosis, re-operation, tumors, infections, traumatic diseases, severe comorbidities, use of walking aids, cognitive decline, and those with hip flexion range of motion limitations affecting sit-to-stand movements. The outcome measures were age, sex, BMI, postoperative period, Oswestry Disability Index (ODI), lumbar pain VAS, 30-second chair stand test (CS-30), Functional Reach Test, isometric trunk muscle strength (flexion, extension), difficulty in standing, and trunk forward acceleration during sit-to-stand movements. The difficulty in standing was assessed using a 7-point Likert scale. Trunk forward acceleration was measured using a tri-axial accelerometer (TSND151, ATP-Promotions) attached to the sternum, with sit-to-stand movements from a seated position recorded. The movement was performed three times, and the average was used as the representative value. The Root Mean Square (RMS) was calculated from the obtained values as the variable. The sampling frequency was set at 100 Hz. Statistical analysis was conducted to compare each outcome measures between the SF and LF groups (significance level 5%).
The SF group consisted of 12 subjects (7 females, The mean age was 70.1 years), and the LF group consisted of 9 subjects (9 females, The mean age was 75.8 years). The group comparison (SF group, LF group) revealed significant differences in RMS [m/s²] (3.27 ± 0.67, 3.91 ± 0.61), CS-30 [times] (15.7 ± 3.7, 12.7 ± 1.5), and gender (p 0.05). No significant differences were observed for other outcome measures.
The LF group had a lower sit-to-stand ability compared to the SF group, but it was within the normal range. Additionally, the LF group adopted a movement strategy that involved accelerating the center of mass forward more during sit-to-stand movements. This is thought to result from the greater center-of-mass movement required due to spinal rigidity caused by the spinal fixation.
It is necessary to instruct post-spinal correction fusion patients with multiple vertebrae fixation to adopt a movement strategy that involves significant center-of-mass movement during sit-to-stand from an early stage.
sit-to-stand movements
triaxial accelerometer
