Lower-Extremity Muscle Cross-Sectional Area After Incomplete Spinal Cord Injury
Presented in part to the American Congress of Rehabilitation Medicine, September 2004, PonteVedra Beach, FL.
Abstract
Shah PK, Stevens JE, Gregory CM, Pathare NC, Jayaraman A, Bickel SC, Bowden M, Behrman AL, Walter GA, Dudley GA, Vandenborne K. Lower-extremity muscle cross-sectional area after incomplete spinal cord injury.
Objectives
(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.
Design
Case-control study.
Setting
University research setting.
Participants
Seventeen people with incomplete SCI and 17 age-, sex-, weight-, and height-matched noninjured controls.
Interventions
Not applicable.
Main Outcome Measures
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 (≈31%) compared with the lower-leg muscles (≈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.
aDepartment of Physical Therapy, University of Florida, Gainesville, FL
bDepartment of Physiology and Functional Genomics, University of Florida, Gainesville, FL
cDepartment of Kinesiology, University of Georgia, Athens, GA
dMalcom Randall VAMC, Brain Rehabilitation Research Center, Gainesville, FL
Reprint requests to Krista Vandenborne, PT, PhD, Dept of Physical Therapy, PO Box 100154, University of Florida, Gainesville, FL 32610
Supported by the National Institutes of Health (grant nos. NIH-RO1HD037645, NIH-KO1HD01348) and by the Veterans Affairs Rehabilitation Research and Development (grant nos. F2182C, B3461H).
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.
ABSTRACT