Objective The aim of this work was to identify factors predictive of postoperative improvement of camptocormia in patients with Parkinson's disease (PD) treated by subthalamic nucleus (STN) stimulation.

Background Camptocormia, one of the most disabling features of PD, often responds poorly to medical therapies. The reported effects of deep brain stimulation on PD-associated camptocormia vary, and preoperative characteristics affecting the surgical outcome remain unclear.

Methods We evaluated 17 patients with camptocormia whose preoperative off-medication thoracolumbar angle exceeded 45°. We used photographs to measure their thoracolumbar angle preoperatively, 3 months after surgery, and at the last follow-up (mean 36.5 months postoperatively) in status on-medication and off-medication. The patient age, duration of PD and camptocormia, daily medications, Unified Parkinson's Disease Rating Scale (UPDRS) subscores and the Schwab-England activity of daily living scale (S-E) were also recorded. Univariate analysis was performed to identify factors predictive of the postoperative improvement of camptocormia.

Results STN stimulation significantly improved the UPDRS subscores and S-E, and resulted in a reduction of daily medications 3 months post-treatment. The preoperative thoracolumbar angle (mean±SD) in status off-medication (84.0±29.5°) was significantly ameliorated 3 months postoperatively (49.8±29.3°) and at the last follow-up (54.8±28.3°). There was no correlation between the postoperative camptocormia improvement rate and preoperative parameters other than the duration and severity of camptocormia and the levodopa responsiveness of the thoracolumbar angle. Symptom duration negatively affected levodopa responsiveness.

Conclusions STN stimulation improves PD-associated camptocormia in parallel with preoperative levodopa responsiveness. Long symptom duration interferes with levodopa responsiveness.