The Relation of Paraspinal Muscles and Degenerative Lumbar Spondylolisthesis

Chae, Soo Uk; Shim, Dae Moo; Kim, Tae Kyun; Kim, Yeung Jin; Kim, Byung Soo

Abstract

OBJECTIVES
To evaluate the cross-sectional area (CSA) and the moment arm length (MAL) of the paraspinal muscles in the degenerative lumbar spondylolisthesis patients compared to the matched control patients, which is through contribution to the stability of the back.
MATERIALS AND METHODS
We studied a comprised of 25 degenerative lumbar spondylolisthesis on L4/5 patients and a controlled group with 42 chronic lower back pain patients. In both groups, we measured body mass index (BMI, kg/m2). On the standing lateral radiographs, we measured the total lumbar lordosis, and segmental lumbar lorodosis using Cobb's methods. We measured the degree of slippage by Meyerding classification. The CSA of erector spinae (CSA) and CSA of psoas were measured at the L4/5 level by using the MRI. The statistical analysis were performed to know the relationship between the CSA and the MAL of erector spinae, and the BMI. Multifidus and erector spinae atrophy were evaluated at the L4/5 level and the degree of fatty atrophy was estimated using three grades : mild, moderate, and severe.
RESULTS
The patient group and the controlled group BMI (kg/m2) were 25.27+/-3.8 and 24.47+/-3.24. In patient group, Meyerding classification grade I was 92%. Total lumbar lordosis and each segmental lordosis were measured mean angle 44.54degrees(24.9degrees~70.4degrees), and each 9.23degrees(L3/4), 10.27degrees(L4/5), 18.81degrees(L5/S1). Pearson's rho indicated a positive association between the CSA and BMI (rho=0.603, p= 0.001), between the CSA of psoas and BMI (rho=0.445, p=0.026), and between the CSA and MAL (rho=0.627, p=0.001) in the degenerative lumbar spondylolisthesis patients. In terms of the CSA versus MAL, there was a positive association in the both groups (rho=0.627, p=0.001, MAL=0.0008 CSA+/-5.293 in the degenerative lumbar spondylolisthesis group; rho=0.812, p=0.000, MAL=0.001 CSA+/-5.245 in the control group with using linear regression analysis). Independent t-test revealed that both groups had statistically different mean values (p=0.038) in terms of the CSA. Proportion of fat deposits in the multifidus and erector spinae muscle at the L3/4 level were all mild grades.
CONCLUSION
The patients with degenerative lumbar spondylolisthesis had atrophied erector spinal muscles, which means harmful because of the poor compensation for the lower back load and poor assists to the lumbar stability. This suggests that the biomechanical factor of the muscles influence to the lumbar disability.