Devoted to diagnostic and interventional spine imaging and therapeutics


Development of a Grading System to Measure Atrophy of the Posterior Paraspinal Muscles 2012

General Spine

Esther, E, Coronel, MD
A. Orlando, Ortiz, MD, MBA, FACR, Non ASSR Member
Joseph, Mazzie, DO, Non ASSR Member



To develop a grading system, utilizing the psoas muscle as an internal reference, to measure atrophy of the lumbar paraspinal muscles.

Methods & Materials

Numerous studies have demonstrated atrophy, defined in our study as decrease in size and fatty replacement of the lumbar paraspinal muscles, following manipulation of the lumbar spine. This study examined the extent of muscle atrophy in patients presenting with back pain symptoms. The etiology of the muscle atrophy was assessed in each case. Imaging studies included computed tomography and magnetic resonance imaging. The cross-sectional area and signal intensity/attenuation were compared to that of the psoas muscle, which served as the internal reference. A grading system consisting of normal (0), mild (1), moderate (2) and severe (3) was utilized by 3 independent readers. The images that were analyzed for every case included axial images at the L1-2, L4-5 and L5-S1 disc space levels and a coronal image at the interspinous level.


Utilizing the psoas muscle as an internal reference, a grading system to measure atrophy was developed. Consistent grading between observers of the extent of muscle atrophy was noted.


A grading system to assess the lumbar paraspinal musculature can be used to categorize the severity of atrophy in specific clinical scenarios. The extent of muscle atrophy may have further implications in terms of persistence of back pain symptomatology, recovery, and rehabilitation.

References/Financial Disclosures

Ashry R, Schweitzer ME, Cunningham P, et al. Muscle atrophy as a consequence of rotator cuff tears: should we compare the muscles of the rotator cuff with those of the deltoid? Skeletal Radiol 2007;36: 841-845 Financial Disclosures: E. Coronel: none A.O. Ortiz: Speakers Bureau - Medtronic Spine, Orthovita Spine J. Mazzie: none