Clinical outcomes after pallidotomy for dystonia: A pilot study of lesion volume and topography

Deep Brain Stimulation(DBS) of the globus pallidus internus(GPi) is the current surgical standard for medically refractory dystonia; pallidotomy offers a cost-effective alternative.

To evaluate clinical outcomes, safety, and radiological correlates of radiofrequency pallidotomy in patients with medically refractory generalised or segmental dystonia.

Twenty-one patients who underwent unilateral or bilateral radiofrequency pallidotomy (2017-2024) were included in an ambispective analysis. Outcomes were measured using Burke-Fahn-Marsden Dystonia Rating Scale motor(BFMDRS-M) and disability(BFMDRS-D) scores. Post-operative MRI was used to quantify lesion volume and location, and correlations with clinical improvement were analysed.

At a mean follow-up of 26.3 ± 21.6 months, BFMDRS-M improved by 35.4 ± 50.4% and BFMDRS-D by 33.1 ± 33.4%. Clinically meaningful improvement (≥30%) was achieved in 66.7% of patients for motor function and 47.6% for disability. Larger total lesion volumes were associated with reduced motor (R = -0.676, p = 0.022) and disability (R = -0.661, p = 0.027) scores; however, this association was no longer present after excluding two patients with disproportionately large lesion volumes. Lesion topography did not correlate with outcomes. Bulbar dysfunction was the most common adverse effect, typically transient. Three patients (14.3%) required further lesioning procedures during follow-up.

In this pilot cohort, pallidotomy appeared to provide clinically meaningful benefit in medically refractory dystonia; however, bulbar adverse effects were frequent underscoring the need for careful patient selection and counselling regarding risk. An association between larger lesion volume and poorer outcome was observed but was driven by two high-volume cases; this preliminary observation requires confirmation in larger, prospective, adequately powered cohorts.