Does Lesion Therapy Still Have a Role in Treating Parkinson’s Disease?

More than a decade ago, Emory became one of the first centers in the U.S. to perform deep brain stimulation (DBS) to treat symptoms of Parkinson’s disease (PD). Since then, DBS has eclipsed lesion therapy as the standard first-line treatment for eligible patients in whom medication therapy is no longer sufficient, whether due to waning of its therapeutic effect, Dyskinesia or side effects. However, stereotactic ablation of the subthalamic nucleus is a potentially effective alternative in patients who do not tolerate DBS, and one that may garner increased attention in the coming years.

In October 2008, a 71-year-old male was referred to the Neurosurgery department at Emory with a 12-year history of PD. In addition to tremor, he also exhibited other PD-related complications, including Dyskinesia. Following evaluation, we determined that he was a candidate for bilateral DBS. Because of his age, we recommended that right and left stimulator implantation be performed in two separate procedures. In November 2008, we implanted a subthalamic deep brain stimulator on the left side. The patient demonstrated a clear positive response to stimulation therapy in the subsequent months, and in May 2009, we implanted a DBS lead on his right side, with both left and right wires running down the right side of his head and neck to a single, double-channel stimulator in his chest.

At a follow-up visit in June 2009, it was discovered that the wires over the right burr hole had become exposed, either due to infection or erosion. With Emory plastic surgeon Albert Losken, MD, we performed a scalp revision, which appeared to be successful. However, in late July, the patient returned to Emory presenting with additional erosion that nearly exposed the ring and cap anchor over the right burr hole. Additional scalp advancement was performed, but in September, another scalp wound had appeared on the top of his head.

At this point, the decision was made to remove and reimplant the right DBS lead, but during surgery, we discovered that the reopening was in fact due to infection around the left-side lead wire, which passed very close to the right. At this point, we decided that the left DBS wire needed to be removed and reimplanted after the infection had cleared. When the patient returned in January 2010, to discuss reimplantation of the left lead, we discovered additional erosion over the remaining right lead and decided it would need to be removed as well. However, because of the clear response from stimulation, we knew we were treating the correct region and decided to use the implanted right lead to create a lesion in the subthalamic nucleus prior to its removal. Following removal of the remaining hardware, the patient underwent antibiotic therapy, which cleared the infection. The right-side lesioning proved to sustain the patient’s symptom improvement, and in April 2010, he underwent stereotactic-guided lesioning of his left subthalamic nucleus. Upon follow-up in February 2011 – 10 months after his second lesioning procedure – his Unified Parkinson’s Disease Rating Scale (UPDRS) Motor Evaluation score off medications was 9, a 60 percent improvement over his score at presentation in 2008. This is generally the degree of improvement expected from bilateral DBS, but actually better than the patient’s own response to this therapy.

More importantly, he was very satisfied with his outcome and is now traveling extensively, without any concerns regarding implanted hardware.DBS is very effective in treating well-selected patients with PD suffering from complications of advancing disease. In this case, however, the patient could not tolerate the treatment. Fortunately, alternative approaches are available, such as lesioning of the subthalamic nucleus or the globus pallidus, the site of pallidotomy, the predecessor to DBS. Stimulation therapy confirmed the target therapeutic region, thereby reducing the risk of permanent lesioning, which was performed as effectively and safely through the DBS lead itself (first side) as it was using a stereotactic approach (second side). In the future, it may be useful to return to the question of whether lesion therapy is as safe and effective – and potentially much less burdensome – than DBS.