Assessment of the cross-sectional areas of the psoas major in patients with adolescent idiopathic scoliosis before skeletal maturity

Abstract

Background The psoas major (PM) can support the lumbar spine and plays an important role in lumbar movement and maintaining lumbar curvature. Purpose To analyze morphological changes of PM and its relation with the severity of adolescent idiopathic scoliosis (AIS). Material and Methods The study was conducted on patients with AIS (age range = 10–18 years) with primary lumbar scoliosis. The cross-sectional area (CSA) of the PM at the L1–L5 levels were measured. The CSA of the PM in patients with AIS was compared with the average CSA of the PM in age-matched controls. The difference in PM at the apical vertebrae level was compared with the Cobb angle to determine the association between PM imbalance and severity of scoliosis. Results The CSA of the PM was larger on the concave side than the convex side at the apical vertebrae level and other lumber levels. Patients with a larger Cobb angle had statistically higher PM imbalance at the apical vertebrae level. The CSA of the PM on both the concave and convex sides of patients with AIS were larger than the average CSA of controls aged 16–18 years; however, there was no significant difference between patients with AIS and controls aged 10–15 years. Conclusion There is a significant PM imbalance in patients with AIS before skeletal maturity, and the imbalance is related to the severity of scoliosis. The morphology of PM changed with the progression of scoliosis.

Is Lenke type V adolescent idiopathic scoliosis associated with different muscular morphometry?

“…Banno et al [28] conducted that the CSA of the PM muscle was not significantly different between kyphosis patients with mild scoliosis and age-matched and body weight-matched control group. It is conducted that there is a significant PM imbalance in patients with AIS before skeletal maturity, and the imbalance is related to the severity of scoliosis and that the morphology of PM changed with the progression of scoliosis [7]. In our study, we found no difference for PM muscle between Lenke V and control groups.…”

“…An important difference between progressive and nonprogressive scoliosis might lie in the differing muscle activation strategies adopted by individuals [6]. Significant psoas major (PM) imbalance exists in patients with AIS before skeletal maturity, and the imbalance is related to the severity of scoliosis [7]. The relative abdominal muscle thicknesses including rectus abdominis (RA) in the AIS patients were found to be more asymmetric than healthy adolescents [8].…”

“…Alterations in muscle morphometry have been documented in AIS frequently [6][7][8]. However, paraspinal muscle and RA morphometry has not been analyzed in subtypes of AIS, a condition with strong physiotherapy connotations, especially in the lower grades.…”

Effectiveness of Botulinum Neurotoxin in Treatment of Scoliosis among Children and Adolescents: A Systematic Review and Meta-Analysis

“…Histologically, a study observed that the fatty infiltration rate was considerably higher in the concave-side muscles, and the authors concluded that these abnormalities may be explained by paraspinal muscle adaptation to the increased loading demand on the convex side of the curve [ 18 ]. By contrast, one study reported that the cross-sectional area of the psoas major muscle was larger on the concave side of the lumbar scoliosis before skeletal maturity, and higher psoas major muscle imbalance at the apical vertebral level was correlated to a larger Cobb angle [ 20 ]. Considering that the muscle volume and cross-sectional area are proportional to muscle strength [ 36 ], abnormally stronger psoas major muscles on the concave side might play a pathomechanic role in AIS.…”

“…In some neuromuscular disorders such as cerebral palsy, the muscle imbalance around the spinal axis caused by spastic or flaccid muscles is believed to be associated with spinal deformity [ 14 ]. Previous studies have reported the presence of electrophysiological and radiological muscle imbalance in idiopathic scoliosis [ 15 , 16 , 17 , 18 , 19 , 20 ]. By modulating the hypertonic muscles in neuromuscular scoliosis and rebuilding the balance between muscle pairs in idiopathic scoliosis with BoNT, it is reasonable to expect the effect in reducing Cobb angles.…”