Asian Spine J.  2018 Apr;12(2):335-342. 10.4184/asj.2018.12.2.335.

Relationship between Displacement of the Psoas Major Muscle and Spinal Alignment in Patients with Adult Spinal Deformity

• Oda Y
• Takigawa T
• Ugawa R
• Shiozaki Y
• Misawa H
• Sugimoto Y
• Tanaka M
• Ozaki T

• KMID: 2410854
• DOI: http://doi.org/10.4184/asj.2018.12.2.335

Abstract

STUDY DESIGN: Cross sectional study. PURPOSE: To clarify the difference in position of the psoas muscle between adult spinal deformity (ASD) and lumbar spinal stenosis (LSS). OVERVIEW OF LITERATURE: Although it is known that the psoas major muscle deviates in ASD patients, no report is available regarding the difference in comparison with LSS patients.
METHODS
This study investigates 39 patients. For evaluating spinal alignment, pelvic tilt (PT), pelvic incidence (PI), sacral slope, lumbar lordosis (LL), PI-LL, Cobb angle, and the convex side, the lumbar curves were measured. For measuring the position of the psoas major at the L4/5 disk level, magnetic resonance imaging was used. The displacements of psoas major muscle were measured separately in the anterior-posterior and lateral directions. We examined the relationship between the radiographic parameters and anterior displacement (AD) and lateral displacement (LD) of the psoas major muscle.
RESULTS
AD was demonstrated in 15 cases with ASD and nine cases with LSS (p>0.05). LD was observed in 13 cases with ASD and no cases with LSS (p < 0.01). The Cobb angle was significantly greater in cases with AD than in those without AD (p=0.04). PT, LL, PI-LL, and Cobb angle were significantly greater in cases with LD (p < 0.05). All cases with LD had AD, but no case without AD had LD (p < 0.001). The side of greater displacement at L4/5 and the convex side of the lumbar curve were consistent in all cases.
CONCLUSIONS
Despite AD being observed in LSS as well, LD was observed only in the ASD group. Radiographic parameters were worse when LD was seen, rather than AD.

Keyword

Psoas muscle; Lumbar vertebrae; Scoliosis; Posture; Enthesopathy

MeSH Terms

Adult*
Animals
Congenital Abnormalities*
Humans
Incidence
Lordosis
Lumbar Vertebrae
Magnetic Resonance Imaging
Posture
Psoas Muscles
Rheumatic Diseases
Scoliosis
Spinal Stenosis