Anterior and posterior sagittal shift in cervical dystonia: A clinical and electromyographic study, including a new EMG approach of the longus colli muscle

Abstract

Anterior and posterior sagittal shift of the head are less common postures in cervical dystonia and, as such, have not been comprehensively studied. In this article, we have detailed both our clinical and electromyography (EMG) findings in 11 patients with prominent dystonic sagittal shift of the head. A new technique of injection of the longus colli, based on a laterocervical approach under EMG guidance, is described. We have detailed the clinical phenotypes of dystonic posterior sagittal shift or "double chin" posture (4 patients) and anterior sagittal shift or "goose neck" posture (7 patients) and proposed specific botulinum toxin (BoNT) treatment protocols for these postures. Seven patients with the goose-neck posture responded well (70%-90% benefit) to BoNT injections. Six patients responded to splenius capitii injections alone, and 1 patient needed, in addition, the injection into both sterno-cleido-mastoid muscles. Four patients with the double-chin posture responded well to BoNT injection (50%-80% benefit). Two patients responded to suprahyoid injection alone, and 2 patients needed, in addition, the injection into the sterno-cleido-mastoid and longus colli muscles. Dysphagia was avoided in all of the double-chin patient group by adjusting our injection technique into the suprahyoid and longus colli muscles. The individualised toxin BoNT protocols have resulted in an improved benefit. The new Longus colli injection technique has allowed for a therapeutic effect of botulinum toxin without causing dysphagia.