Pallidal deep brain stimulation relieves camptocormia in primary dystonia

Camptocormia, characterised by a forward flexion of the thoracolumbar spine may occur in various movement disorders, mainly in Parkinson's disease or in primary dystonia. In severe cases, patients with camptocormia are unable to walk. While treatment options are limited, deep brain stimulation (DBS) with bilateral stimulation of the subthalamic nucleus or globus pallidus internus (GPi) has been proposed as a therapeutic option in refractory cases of Parkinson's disease. Here we present two patients with severe camptocormia as an isolated form of dystonia and as part of generalised dystonia, respectively, which were both treated with bilateral stimulation of the GPi. Symptoms of dystonia were assessed using the Burke-Fahn-Marsden dystonia rating scale (BFM) before and during deep brain stimulation. In both patients there was a significant functional improvement following long-term bilateral GPi stimulation and both patients gained ability to walk. In the first patient with an isolated dystonic camptocormia the BFM motor subscore for the truncal flexion improved by 75 %. The total BFM motor score in the second patient with a camptocormia in generalised dystonia improved by 45 %, while the BFM score for truncal flexion improved by 87 %. In both patients the effect of the bilateral GPi stimulation on camptocormia was substantial, independent of generalisation of dystonia. Therefore, GPi DBS is a possible treatment option for this rare disease.