Article
Camptocormia in PD: How pathomorphological findings translate to therapy
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Published: | August 25, 2015 |
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Camptocormia (from the Greek “kamptein“ = to bend and “kormos“ = trunk) is an abnormal flexion of the thoraco-lumbar spine when standing or walking that disappears in the supine position. It occurs in nearly 10% of Parkinson’s disease (PD) patients. We have recently reported that camptocormia in Parkinson’s disease is associated with a myopathy that can be defined by pathological core features:
- 1.
- myopathic changes with type-1 fiber hypertrophy, loss of type-2 fibers, loss of oxidative enzyme activity and acid phosphatase reactivity of lesions and
- 2.
- myofibrillar disorganization and Z-band streaming up to electron-dense patches/plaques that were detectable ultrastructurally.
Secondary changes are endomyseal fibrosis and fatty degeneration.
Surprisingly, a lesion pattern in muscles that reflects all aspects, we have found in our PD camptocormia patients, has been observed after expermental tenotomy. These changes cannot be observed in denervated tenotomised muscles or in tenotomised muscles after chordotomy. Obviously, the experimental lesions depend on disturbances of muscle tension reflex mechanisms, but the reflexes need to be functionally intact. The similarities between the muscle pathology of the experimental tenotomy and camptoicormia in PD point towards that camptocormia may also be related to a proprioceptive dysregulation. A proprioceptive dysregulation may explain the clinical symptoms of rigidity and loss of muscle strength in camptocormia.
When a proprioceptive dysregulation is the underlaying mechanism in camptocormia, it would be likely, that deep brain stimulation (DBS) of the subthalamic nucleus has a beneficial effect on camptocormia. It is known that DBS of the STN can improve the proprioceptive function and an impairment of the proprioception in PD is known.
In a retrospective analysis of 25 PD patients who underwent DBS of the STN the bending angle of camptocormia in 13 patients improved, in 12 patients not. A multifactorial analysis revealed a short duration between onset of camptocormia and start of neurostimulation to be the relevant factor for outcome. STN-DBS may partially restore the proprioception and thus may be an efficacious treatment for camptocormia, as long as secondary myopathic changes are not yet advanced.