Sustained Effect of Posteroventral Pallidotomy for X-Linked Dystonia Parkinsonism

Background: X-linked dystonia parkinsonism (XDP, DYT3), a disease endemic to Panay Island in the Philippines, is a progressive adult-onset sex-linked neurodegenerative movement disorder with features of both dystonia and parkinsonism. Medical treatment and botulinum toxin injection (BTX) are of limited benefit. Deep brain stimulation (DBS) of the bilateral globus pallidus internus (GPi) is effective but is expensive and requires specialized equipment, training and after care. Posteroventral pallidotomy (PVP) is an older known ablative procedure which has successfully treated cervical and generalized dystonia, but has not been previously used for XDP. Case presentation: Two male adults with genetically-confirmed XDP, presented with progressive and severely disabling dystonias. The mean preoperative Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) was 80.5. Both XDP patients underwent a unilateral posteroventral pallidotomy. In the first case, there was a 38.46% decrease in BFMDRS score at 2 weeks sustained to 41.66% decrease (compared to pre-op BFMDRS at 4 years post-surgery). In the second case, there was a 33.73% decrease in BFMDRS at 2 months post-op, and a decrease of 86.74% in BFMDRS score at 3 years post-surgery. Conclusion: While not as effective as bilateral pallidal DBS, the benefits of a unilateral PVP are still substantial and sustained while also being less costly and resource expensive.