Bilateral pallidotomy for acquired or heredodegenerative generalized dystonia in children

Abstract

OBJECTIVE Dystonias are relatively rare disorders characterized by sustained or intermittent muscle contractions causing abnormal movements or postures. Generalized dystonia is a therapeutic challenge because medications are unable to control dystonia adequately in most patients. These patients may be candidates for surgical therapy. The commonly used surgical procedures in these patients are pallidotomy and deep brain stimulation. Limited studies are available on the role of pallidotomy in children with acquired/heredodegenerative generalized dystonia. The objective of this study was to describe the authors’ experience with bilateral pallidotomy in this group of patients. METHODS The authors retrospectively reviewed all pediatric patients (less than 18 years of age) with acquired/heredodegenerative generalized dystonia who underwent bilateral simultaneous pallidotomy at their center between January 2014 and January 2021. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores before and after surgery were recorded. Complications arising after the procedure were recorded as well. RESULTS Ten patients (8 male and 2 female) with a mean (range) age of 11.1 (5–17) years were included in this study. The mean duration between disease onset and surgical intervention was 3.9 years. Two patients presented in status dystonicus. The mean ± SD (range) preoperative BFMDRS score of the patients without status dystonicus (n = 8) was 80 ± 18.9 (59.5–108). The mean ± SD BFMDRS score at the time of discharge from the hospital after surgery was 58.8 ± 37.9. Three patients had more than 20% change in BFMDRS score at the time of discharge from the hospital. The mean improvement was 25.5% at the end of 1 year. Of 5 surviving patients in the non–status dystonicus group, 3 patients had more than 40% change in BFMDRS score while the other 2 patients developed recurrence at the last follow-up (4.5 years). Status dystonicus abated after bilateral pallidotomy in both patients. Permanent bulbar complications were seen in 2 patients. CONCLUSIONS Bilateral pallidotomy may result in clinically significant improvement in children with acquired/heredodegenerative generalized dystonia, although the benefits should be closely weighed against the risk of irreversible bulbar dysfunction. It is a viable option for children in resource-limited settings.

Neurosurgical management of non-spastic movement disorders

“…Although specific epidemiologic data is lacking, PMDs are among the most common reason for presentation to a pediatric neurology clinic [ 4 ]. Tics are the most common manifestation followed by dystonia [ 5 ]. Tics, stereotypies, and psychogenic PMDs generally are treated non-surgically as most, and specifically tics, improve with age [ 6 ].…”

“…The modern medical management algorithm in Fig. 1 is commonly effective for hypertonia; however, the PMD inevitably progresses or is worsened by physiologic growth which causes musculoskeletal dysfunction, physical disability, poor quality of life, and premature death [ 5 , 28 – 30 ]. Neuroablative therapies for PMDs include CNS lesions and rhizotomy.…”

“…Secondary dystonic patients remain recalcitrant to medico-surgical techniques. Unfortunately, they respond significantly less to thalamotomy or pallidotomy than primary dystonic patients [ 5 , 23 ]. A modern series of 10 children with mixed etiologies for secondary generalized dystonia treated at a single center showed a moderate efficacy and safety profile.…”

“…No patients had worsening symptoms following pallidotomy; while three died following intervention they were from COVID-19 and Wilson’s disease-related liver failure, with only one death 2 years following pallidotomy-related bulbar dysfunction. The Burke‐Fahn‐Marsden dystonia rating scale (BFMDRS) was reduced 25.5% on average 1 year following the procedure with some responders achieving 40% reduction of dystonia [ 5 ].…”

“…Features of dystonia which are positively correlated with improvement following pallidotomy include a primary neurogenetic condition, MRI “lesion-negative,” and shorter course of disease [ 34 ]. Bulbar dysfunction is a known consequence of bilateral pallidotomy, and this morbidity profile is considered better than that from thalamotomy [ 5 , 23 ]. The reduction of dystonia in the pediatric population is modest based on the handful of case series that exist in the literature [ 34 – 38 ]; the small number of case series in context of the many decades of available therapy may highlight a publication bias against negative results or poor outcomes.…”