Stable muscle atrophy in long-term paraplegics with complete upper motor neuron lesion from 3- to 20-year SCI

• Published in: Spinal cord Vol. 46; no. 4; pp. 293 - 304
• Main Authors: Kern, H, Hofer, C, Mödlin, M, Mayr, W, Vindigni, V, Zampieri, S, Boncompagni, S, Protasi, F, Carraro, U
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2008; Nature Publishing; Nature Publishing Group
• Subjects: Adult; Anatomy; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Case-Control Studies; Cerebrospinal fluid. Meninges. Spinal cord; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Human Physiology; Humans; Male; Medical sciences; Muscle Strength - physiology; Muscular Atrophy - diagnostic imaging; Muscular Atrophy - etiology; Muscular Atrophy - pathology; Nervous system (semeiology, syndromes); Neurochemistry; Neurology; Neuropsychology; Neurosciences; original-article; Paraplegia - complications; Paraplegia - pathology; Paraplegia - physiopathology; Quadriceps Muscle - diagnostic imaging; Quadriceps Muscle - pathology; Quadriceps Muscle - physiopathology; Radiography; Spinal Cord Injuries - complications; Spinal Cord Injuries - pathology; Spinal Cord Injuries - physiopathology; Thoracic Vertebrae; Time Factors; biopsy; histopathology and electron microscopy; paraplegia; CT scan; upper motor neuron lesion; human muscle; Human; Nervous system diseases; Vertebral canal; Motor system disorder; Amyotrophy; Motor neuron; Electron microscopy; Long term; Striated muscle disease; Paraplegia; Histopathology; Biopsy; Central nervous system disease; Computerized axial tomography; Neurological disorder; Spinal cord disease
• ISSN: 1362-4393; 1476-5624
• DOI: 10.1038/sj.sc.3102131

Study design: Unrandomized trial. Objectives: To investigate the structural and functional relationships and the progression of muscle atrophy up to 20 years of spastic paraplegia. Setting: Clinical follow-up in Vienna, Austria; muscle biopsies analyzed by light microscopy in Padova and by electron microscopy (EM) in Chieti, Italy. Methods: Force was measured as knee extension torque; trophism by computer tomography scan; tissue composition and fiber morphology by histopathology and EM. Results: In the long-term group of patients (17.0±2.6 years), force and size of thigh muscles were only slightly different from those of mid-term subjects (2.2±0.5 years). Histology and ultrastructure confirm that the difference in average size of muscle fibers between long-term and mid-term paralyzed leg muscles is actually very small. In addition, muscle fibers maintain the striated appearance characteristic of normal skeletal fibers even after 14–20 years of paralysis. Ultrastructural alterations of the activating and metabolic machineries, and the presence of fibers with lower motor neuron denervation features, may explain the low-force output and the reduced endurance of paretic muscles. Conclusion: The stable muscle atrophy that characterizes long-lasting spastic paraplegia suggests that there are no upper-time limits to begin a training program based on functional electrical stimulation.