[Purpose] Degenerative Lumbar Scoliosis (DLS) is increasing rapidly with aging. There are many cross-sectional studies showing the relationship between skeletal muscle loss and DLS, but there are no longitudinal studies. In this study, we investigated changes in skeletal muscle mass and bone mineral density in DLS patients during 2-year follow-up.

[Method] Of the 1596 women aged 40 and over (mean age 74 years, range 40-99) who underwent standing lumbar x-ray with measurement of body composition and bone mineral density, 418 women who could be observed for more than one year are included in this study. The study was divided into 50 patients in the DLS group (mean 76 years) and 368 patients in the control group (mean 73 years). The diagnosis of DLS was lumbar Cobb angle: 10 ° or more and SVA: 50 mm or more. Whole-body skeletal muscle mass was measured using a Bioelectrical impedance analyzer (BIA). Bone mineral density (BMD) was measured using DXA. Skin autofluorescence (SFA) was measured using a spectroscope AGE reader. Spinal alignment, skeletal muscle mass, BMD, grip strength, and SFA were examined in both groups, and the amount of change in Follow up (f/o) 1 year and 2 years from the initial examination for each item was compared in both groups.

[Results] Compared with the control group, the height, body fat mass, grip strength, upper limb muscle mass, and trunk muscle mass were significantly decreased, and the lumbar spine bone mineral density was significantly increased (p<0.05). There was no significant difference in spinal alignment for 2 years at f / o in the DLS group(p>0.05).

On the other hand, regarding the amount of change in each parameters during f/o 2 years between the two groups, the height decreased significantly in the DLS group (-0.9%) compared to the control group (-0.3%) in the f/o 2 years (p <0.05). Trunk muscle mass decreased significantly in the DLS group (-2.8%) compared to the control group (-1.1%) at f/o 2 years (p <0.05).

[Discussion] It has been reported that DLS has a high rate of sarcopenia and low trunk muscle mass is an age-independent risk factor. However, this is a cross-sectional study, and the mechanism of skeletal muscle loss and DLS progression is unclear. From this study, it was shown that the trunk muscle mass in the DLS group decreased significantly by about 2.5 times in 2 years compared with the control group. In DLS, trunk muscle atrophy is progressing due to a decrease in activity associated with kyphoscoliosis, and there is a possibility that a vicious cycle of kyphoscoliosis has occurred. In the future, it may be possible to clarify the mechanism of kyphoscoliosis progression by continuing large-scale longitudinal studies.