Spectrum of Truncal Dystonia and Response to Treatment: A Retrospective Analysis

Background: Presence of truncal dystonia usually points to a secondary cause of dystonia like exposure to dopamine receptor blockers or neurodegenerative illness. Rarely, it can occur as an idiopathic focal or segmental dystonia.

Methods: Retrospective review of medical records and videos of patients of truncal dystonia presenting in the Botulinum Toxin Clinic of Department of Neurology at Post Graduate Institute of Medical Education and Research, Chandigarh between May 2016 and February 2019.

Results: A total of 16 patients with predominant truncal dystonia were recruited. There were ten males and six females with mean age of 49.1 ± 15.1 years (range 22-70). Extensor truncal dystonia was the most common (12/16) followed by camptocormia (4/16). Various etiologies included Idiopathic Parkinson's disease (4/16), Tardive dystonia (5/16), Neurodegeneration with brain iron accumulation (genetically confirmed) (2/16) and idiopathic (5/16). All patients were refractory to a combination of oral medications tried over a period of 1.82 ± 1.93 years. All patients received electromyographic-guided botulinum toxin in paraspinals or rectus abdominis muscles depending upon the type of dystonia. The mean dose of abobotulinum toxin used was 286.7 ± 108.6 units (range 200-500 units) for paraspinals and 297.5 ± 68.5 (range 200-350) for rectus abdominis muscles per session. Average subjective response after botulinum toxin injection session was 31.2 ± 21.5% (range 0-70). No adverse effects were reported.

Conclusion: Botulinum toxin is an acceptable alternative to patients presenting with medically refractory truncal dystonia and may offer modest benefit.