Postoperative 18F-FDG-PET/CT documents efficacy of selective peripheral denervation for treating cervical dystonia

Current use of neurotoxins for alleviating symptoms of cervical dystonia

INTRODUCTION

Cervical dystonia (CD) causes involuntary movements and postures of the head, neck, and shoulders, as well as nonmotor symptoms including pain, mood, and sleep dysfunction, and impacts quality of life. The first-line treatment for CD is botulinum neurotoxin (BoNT) injections.

AREAS COVERED

The clinical presentation and diagnosis of CD, as well as where BoNT resides in the treatment landscape, is reviewed first. Next, the mechanism of action and the pharmacological differences in the available preparations of BoNT products are explained. The evidence base for motor and nonmotor efficacy and safety of the available BoNT formulations is reviewed, with attention to duration of benefit as a driver of patient satisfaction. Practical determinants of BoNT efficacy are reviewed including muscle selection, accurate muscle injection, factors related to poor or deteriorating response, and immunogenicity.

EXPERT OPINION

BoNT represents a significant advancement in the treatment of CD. More accurate diagnosis, muscle selection and targeting, and dosing can improve outcomes with existing BoNT formulations. Further refinement of BoNT potency, duration of action, safety, and immunogenicity will help reduce unmet needs in the magnitude and duration of benefit. Additional validation of DBS and MRI-guided focused ultrasound may expand options for patients with toxin nonresponse.

Myotomy and Selective Peripheral Denervation Based on 18F-FDG PET/CT in Intractable Cervical Dystonia: A Case Report

Cervical dystonia, characterized by the involuntary contraction of cervical muscles, is the most common form of adult dystonia. In a patient with intractable cervical dystonia, we carried out a myotomy of the left obliquus capitis inferior and selective peripheral denervation (SPD) of the posterior branches of the C3-C6 spinal nerves based on preoperative 18F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT). The patient was a 65-year-old, right-handed man with an unremarkable medical history. His head rotated involuntarily to the left. Medication and botulinum toxin injections were ineffective, and surgical treatment was considered. ¹⁸F-FDG PET/CT imaging revealed FDG uptake in the left obliquus capitis inferior, right sternocleidomastoideus, and left splenius capitis. Myotomy of the left obliquus capitis inferior and SPD of the posterior branches of the C3-C6 spinal nerves was performed under general anesthesia. During the 6-month follow-up, the patient's Toronto Western Spasmodic Torticollis Rating Scale score improved from 35 to 9. This case shows that preoperative ¹⁸F-FDG PET/CT is effective in identifying dystonic muscles and determining the surgical strategy for cervical dystonia.