217 - Muscular Volume and Fat Infiltration Parameters of the Spino-pelvic Co...

#217 Muscular Volume and Fat Infiltration Parameters of the Spino-pelvic Complex Correlate with HRQOL and Skeletal Malalignment in Adult Spinal Deformity

Cutting Edge Innovations/Non-conventional Therapies

Poster Presented by: S. Liu

Author(s):

B. Moal (1,2)
S. Liu (1)
J. Terran (1)
N. Bronsard (1,3)
T. Protopsaltis (1)
J.-M. Vital (1,4)
W. Skalli (1,2)
F.J. Schwab (1)
V. Lafage (1)

(1) NYU Hospital for Joint Diseases, Orthopaedic Surgery, New York, NY, United States
(2) Arts et Metiers Paris Tech, Paris, France
(3) CHU de Nice, Service d'Imagerie Medicale, Nice, France
(4) CHU Pellegrin Tripode, Unite de Pathologie Rachidienne, Bordeaux, France

Abstract

Summary: Typically, only skeletal parameters are used to evaluate adult spinal deformity. Understanding the impact of the muscular system on deformity would greatly enhance diagnosis and treatment in this patient population. Based upon analysis of muscle volume and fat infiltration we have identified several muscle components found to relate to disability and radiographic deformity.

Introduction: Spinal pathologies are mostly analyzed only by skeletal parameters. Understanding of the muscular system is limited but may aid in optimizing diagnosis and treatment of adult spinal deformity (ASD). The purpose of this study was to offer qualitative and quantitative analysis of trunk, pelvic and proximal lower extremity musculature in ASD patients.

Methods: Consecutive female ASD patients (n=19, mean age 60) had MRI (3 T, Magnetom Verio, Siemens Healthcare): T1-weighted TSE sequence for three points Dixon method with imaging from proximal tibia up to T12 vertebra. 3D reconstruction permitted evaluation between muscle volume (MV), and contractile tissue volume (CTV) and contractile ratio (CTV/MV). Height/weight and full free-standing radiographs of the spine/pelvis were obtained, and questionnaires completed (ODI, SRS-23).

Results: No correlation was found between the MV total and age or BMI; CTV correlated with age (r=-0.670) and BMI (r=-0.467). CTV of Erector Spinae correlated only with the age (r=-0.516). Difference in MV and CTV distributions revealed that muscular degeneration impacted more spinal erector. On average the contractile ratio was 81%±8, with significantly smaller ratio for Spinal and Hip Erector (55%). Mismatch in the muscle contractility of hip flexors vs extensors correlated with ODI (r=0.489), SRS Pain (r=-0.490). Increased Pelvic Tilt (PT) correlated with loss in MV of entire muscle system (r=0.46), decreased CTV in spinae erectae (r=0.54). SVA correlated with lower extremities contractile ratio, and fat infiltration in spinae erectae (r=0.501).

Conclusion: As a general rule, CTV was negatively correlated with age and BMI, but the large variability in fat infiltration reveals specificity of spinae erectae. The ratio in contractile components of hip flexors/extensor is tied to disability. Increased PT is associated with decrease in contractile component of spinae erectae, and decrease fat component spine flexors. Evaluation of the quality and proportion of the spino-pelvic muscular system may change the way we evaluate our ASD patients beyond skeletal radiographic parameters.