Study design: This study analyzed computed tomographic scans, magnetic resonance images, and biopsies of the paravertebral muscles of patients with camptocormia and age-matched patients with lumbar interapophyseal osteoarthritis or lumbar vertebral stenosis.
Objectives: To define the muscular lesions and clarify their nature in this particular disorder.
Summary of background data: Progressive lumbar kyphosis or camptocormia, a rare disease of the elderly characterized by inability to immobilize the lumbar spine in relation to the pelvis appears to be a result of weakness of the paraspinal muscles. The features presented by these patients do not correspond to any myopathy previously described.
Methods: Twenty-seven patients (5 men and 22 women) mean age 69 years, with camptocormia were compared to fifteen age-matched patients without camptocormia but with posterior interapophyseal osteoarthritis and to nine elderly patients operated for narrowing of lumbar canal. Computed tomographic scans, magnetic resonance images, light microscopy, histochemistry, and electron microscopy of paraspinal muscles were obtained in both groups.
Results: In patients with camptocormia, computed tomographic scans and magnetic resonance imaging showed heterogeneous appearance of the spinal muscles with areas of low density. These features were distinct from those of patients with interapophyseal osteoarthritis and were similar to the features described in primary muscular dystrophies. The main microscopic change in camptocormia was the increase of fibrous tissue, frequently with a lobular pattern, not seen in osteoarthritic patients. Familial history of the disorder was frequent (20 out of the 27 patients).
Conclusion: Camptocormia, disappearing in the recumbent position, is thus very probably linked to muscle involvement. That there is often a family history of such disorder is in favor of a genetically transmitted condition. Magnetic resonance images and computed tomographic scan appearance seems to be in favor of primary muscular disease, restricted to the spinal muscles.