Previously, Dr. R. A. J. Esselink, from Radboud University Nijmegen Medical Centre, and team presented the 1-year results of their multicenter, randomized trial comparing the two types of surgery, showing that bilateral STN is more effective than pallidotomy. The present study findings are the results after 4 years of follow-up.
The study involved 14 patients who underwent pallidotomy and 20 who underwent STN stimulation. Four patients from pallidotomy group and two patients in the STN group died before the end of 4 years. Due to disease progression, 3 patients in the pallidotomy group switched to STN after 18 to 40 months.
In the intent-to-treat analyses, the median off-phase motor Unified Parkinson’s Disease Rating Scale score increased to 27% in the pallidotomy group and 46% in the STN group. The difference in change scores between the groups was 18.5 points (p = 0.04) supporting STN treatment.
Similarly, the median on-phase motor score worsened by 40% within 4 years after pallidotomy, whereas it was in the STN group it was about stable at 21 points. The difference between the groups was 6.5 points (p = 0.04).
STN still scored significantly more favorably in the on-treatment analysis than pallidotomy or pallidotomy plus STN.
Moreover, the frequency of adverse events was approximately the same for both treatments, Dr. Esselink and associates report. In the pallidotomy group, two severe adverse events occurred that include suicide in one patient and development of dementia in another where as in the STN group one patient developed cognitive and behavioral problems immediately after surgery, and two patients developed dementia.
The most prevalent adverse event associated with pallidotomy was drooling, which occurred in six patients and persisted in three where as in STN group, the most common adverse event was emotional lability, which occurred in six and persisted in three patients.
