Paraspinal muscle fibrosis: a specific pathological component in ankylosing spondylitis.

Abstract

The histological appearance of percutaneous superficial paraspinal muscle biopsy specimens from eight patients with ankylosing spondylitis was compared with that of biopsy specimens from 13 control patients with similar degrees of disability and spinal immobility due to severe, chronic mechanical back pain. In both groups marked type I muscle fibre atrophy was shown. Additionally, in patients with ankylosing spondylitis there were obvious increases in perifibre connective tissue in association with central migration of cell nuclei but without evidence of inflammation. Qualitative electromyography failed to show denervation changes in either group. Paraspinal muscle fibrosis, occurring over and above atrophic changes due to disuse, seems to be a specific pathological component of ankylosing spondylitis which may be of particular importance in early disease as it may contribute towards back stiffness and weakness.

MR-defined fat infiltration of the lumbar paravertebral muscles differs between non-radiographic axial spondyloarthritis and established ankylosing spondylitis

“…We show here that paravertebral muscles of patients with SpA may not necessarily change in size, although their structure may change, with differentiation towards fatty degeneration. The histopathologic study revealed that selective type-2 fibre atrophy was present in both patients with AS and those with chronic mechanical back pain as a consequence of reduced motor activity [2]. This situation differs from the atrophy of both type-1 and type-2 fibers observed after neurogenic events, such as nerve root compression.…”

“…Peripheral joint and extra-articular involvement, such as dactylitis, uveitis, enteric mucosal lesions and skin lesions, are manifestations common to SpA patients [1]. In addition, muscles, particularly paravertebral muscles, are affected in AS [2][3][4][5][6]. Restricted spinal movements are a well-known disease process, and the potential disuse of paravertebral muscles inevitably causes muscle atrophy in established AS, possibly having a considerable effect on the disease process and quality of life [2,7].…”

“…Histopathologic studies have shown changes in the distribution of fiber types in AS patients [2]. The cross-sectional area (CSA) and fat content of lumbar paravertebral muscles of patients with low back pain (LBP) have been evaluated by ultrasonography, CT and magnetic resonance imaging (MRI) [8,9].…”

An Evaluation of Spinal Deformities and Quality of Life in Male Patients with Ankylosing Spondylitis

“…In other studies conducted, it has been observed that patients with AS have increased thoracic kyphosis and cervical lordosis, and decreased levels of lumbar lordosis (15,16). In our study, we used the pendulum method for postural analysis.…”

Muscle Changes in Ankylosing Spondylitis

“…Lumbar pain in ankylosing spondylitis patients strongly suggests that pathology of paraspinal muscles is involved in this disease. This could involve speci fi c pathological damage as well as atrophic changes due to disuse and may occur in many muscles (Cooper et al 1991 ) .…”