Object: Deep brain stimulation (DBS) of the thalamus is used for the treatment of patients with medically refractory essential tremor (ET). The authors evaluated patient outcomes after DBS surgery.
Methods: Clinical outcomes were evaluated in 19 patients who had undergone DBS surgery by using the Fahn-Tolosa-Marin clinical tremor rating scale. All adverse outcomes were also systematically recorded during follow-up outpatient visits. Eighteen DBS systems were implanted. The median follow-up period after surgery was 27 months (range 10-75 months). The preoperative mean Fahn-Tolosa-Marin action tremor score was 3.3 +/- 0.5, and the postoperative mean score with the DBS system activated was 0.8 +/- 0.4. The mean preoperative writing score was 2.8 +/- 0.9, and the postoperative mean writing score with the DBS system activated was 1 +/- 0.6. (Wilcoxon rank-sum test, p < 0.005). Fourteen patients were treated with bipolar stimulation, and four eventually required monopolar stimulation. Complications included lead breakage (one patient); temporary erythema of the incision through which the pulse generator had been implanted, which required oral antibiotics (one patient); electrode migration, which required surgery (one patient); and mild hand tingling during stimulation (three patients). Twelve of 18 patients with implanted systems experienced no morbid condition.
Conclusions: Thalamic DBS is safe and effective for medically refractory ET. Stimulator adjustments can frequently occur in some patients, and tremor may worsen despite a readjustment in the system.