To analyse postoperative pain due to osteoarthritis in patients with Parkinson's disease submitted to bilateral subthalamic nucleus stimulation.
Fifty-three parkinsonian patients (mean age, 59.9 ± 8.3 years; mean disease duration, 11.5 ± 4.2 years) referred for subthalamic nucleus stimulation were enrolled. Patients were prospectively asked to refer and describe any pain due to osteoarthritis they experienced at any time during the preoperative period and within the 6 postoperative months. Pre-existing pain due to osteoarthritis, therapeutic changes, parkinsonian motor disability and weight gain were assessed as explanatory factors for occurrence pain due to osteoarthritis after surgery.
After surgery, thirty patients (57%) complained of pain due to osteoarthritis whereas all demonstrated great functional improvement. Twenty (67%) among the 30 experienced similar pain sensation before surgery. Symptoms occurred rapidly, between 4 and 26 postoperative weeks. Multiple stepwise regression analysis showed that pre-existing pain due to osteoarthritis, 6-month postoperative UPDRS III motor score and axial sub-score improvements in the off-drug/on-stimulation condition were accurate independent predictors of pain due to osteoarthritis after surgery (F(8,41)=2.20, p<0.047).
Our results highlight the high prevalence of pain due to osteoarthritis arising shortly after subthalamic implantation. An accurate pain and osteo-articular assessment should be performed preoperatively in parkinsonian candidates for subthalamic nucleus stimulation in order to limit occurrence of complications in the early postoperative period.