Lower-extremity muscle cross-sectional area after incomplete spinal cord injury.
OBJECTIVE
(1) To quantify skeletal muscle size in lower-extremity muscles of people after incomplete spinal cord injury (SCI), (2) to assess differences in muscle size between involved lower limbs, (3) to determine the impact of ambulatory status (using wheelchair for community mobility vs not using a wheelchair for community mobility) on muscle size after incomplete SCI, and (4) to determine if differential atrophy occurs among individual muscles after incomplete SCI.


METHODS
Case-control study.


METHODS
University research setting.


METHODS
Seventeen people with incomplete SCI and 17 age-, sex-, weight-, and height-matched noninjured controls.


METHODS
Not applicable.


METHODS
Maximum cross-sectional area (CSA) of individual lower-extremity muscles (soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, quadriceps femoris, hamstrings) as assessed by magnetic resonance imaging.


RESULTS
Overall, subjects with incomplete SCI had significantly smaller (24%-31%) average muscle CSA in affected lower-extremity muscles as compared with control subjects (P<.05). Mean differences were highest in the thigh muscles ( approximately 31%) compared with the lower-leg muscles ( approximately 25%). No differences were noted between the self-reported more- and less-involved limbs within the incomplete SCI group. Dichotomizing the incomplete SCI group showed significantly lower muscle CSA values in both the wheelchair (range, 21%-39%) and nonwheelchair groups (range, 24%-38%). In addition, the wheelchair group exhibited significantly greater plantarflexor muscle atrophy compared with the dorsiflexors, with maximum atrophy in the medial gastrocnemius muscle (39%).


CONCLUSIONS
Our results suggest marked and differential atrophic response of the affected lower-extremity muscles that is seemingly affected by ambulatory status in people with incomplete SCI.
Shah
Prithvi K
PK
Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA.
Stevens
Jennifer E
JE
Gregory
Chris M
CM
Pathare
Neeti C
NC
Jayaraman
Arun
A
Bickel
Scott C
SC
Bowden
Mark
M
Behrman
Andrea L
AL
Walter
Glenn A
GA
Dudley
Gary A
GA
Vandenborne
Krista
K
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D009133:Muscular Atrophy / Q000175:diagnosis*; D013119:Spinal Cord Injuries / Q000473:pathology*; D018709:Statistics, Nonparametric