Disuse muscle atrophy of lower limbs in hemiplegic patients.

OBJECTIVE: To clarify the histopathologic findings from lower limb muscles in hemiplegic patients and determine whether the findings are related to the severity of paralysis or daily physical activity.
DESIGN: Nonrandomized control trial.
SETTING: Referral center. PATIENTS: Eight patients were selected from 21 hemiplegic persons who underwent a muscle biopsy, and the controls were four men who had no abnormal findings in their histopathology. MAIN OUTCOME MEASURES: Morphometric evaluations of bilateral vastus lateralis muscles on the involved (I-VL) and non-involved (N-VL) sides in eight hemiplegic subjects, five flexor hallucis longus muscles on the involved side (I-FHL), and vastus lateralis muscles of four controls (C-VL) were performed. Muscle fiber diameters were measured with an image analyzer, and atrophy factors, hypertrophy factors, and fiber type proportions were calculated based on the data.
RESULTS: The morphometric measurements revealed that the hemiplegic patients had type 2 fiber atrophy, type 2B fiber atrophy, and type 2 fiber atrophy with type 1 fiber hypertrophy in the I-VL, N-VL, and I-FHL, respectively, and that the controls had no muscle fiber atrophy or hypertrophy. The muscle fiber atrophy in the hemiplegic patients was not related to the period after the onset, the severity of paralysis, or activities of daily living score but was related to daily physical activity.
CONCLUSIONS: Although the hemiplegic patients had undergone rehabilitative treatments, which did not include muscle strengthening exercises, in a hospital without a board-certified doctor of rehabilitation medicine, a considerable amount of muscle atrophy was found characteristic of changes seen in disuse.