toxins Article Management of Anterocapitis and Anterocollis: A Novel Ultrasound Guided Approach Combined with Electromyography for Botulinum Toxin Injection of Longus Colli and Longus Capitis Michael Farrell 1 , Barbara I. Karp 2, Panagiotis Kassavetis 2, William Berrigan 3 , Simge Yonter 4, Debra Ehrlich 2 and Katharine E. Alter 5,* 1 MedStar/Georgetown University National Rehabilitation Hospital, Washington, DC 20010, USA; [email protected] 2 National Institutes of Neurological Disorders and Stroke, Bethesda, MD 20892 USA; [email protected] (B.I.K.); [email protected] (P.K.); [email protected] (D.E.) 3 Emory School of Medicine, Emory University, Atlanta, GA 30322, USA; [email protected] 4 Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892-1604, USA; [email protected] 5 Functional and Applied Biomechanics Section, Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892-1604, USA * Correspondence: [email protected] Received: 29 August 2020; Accepted: 27 September 2020; Published: 30 September 2020 Abstract: Chemodenervation of cervical musculature using botulinum neurotoxin (BoNT) is established as the gold standard or treatment of choice for management of Cervical Dystonia (CD). The success of BoNT procedures is measured by improved symptomology while minimizing side effects and is dependent upon many factors including: clinical pattern recognition, identifying contributory muscles, BoNT dosage, and locating and safely injecting target muscles. In patients with CD, treatment of anterocollis (forward flexion of the neck) and anterocaput (anterocapitis) (forward flexion of the head) are inarguably challenging. The longus Colli (LoCol) and longus capitis (LoCap) muscles, two deep cervical spine and head flexor muscles, frequently contribute to these patterns. Localizing and safely injecting these muscles is particularly challenging owing to their deep location and the complex regional anatomy which includes critical neurovascular and other structures. Ultrasound (US) guidance provides direct visualization of the LoCol, LoCap, other cervical muscles and adjacent structures reducing the risks and side effects while improving the clinical outcome of BoNT for these conditions. The addition of electromyography (EMG) provides confirmation of muscle activity within the target muscle. Within this manuscript, we present a technical description of a novel US guided approach (combined with EMG) for BoNT injection into the LoCol and LoCap muscles for the management of anterocollis and anterocaput in patients with CD. Keywords: cervical dystonia; botulinum toxins; anterocaput; anterocollis; injection technique; longus colli; longus capitis; ultrasound guidance; head and neck; chemodenervation Key Contribution: This manuscript describes a novel ultrasound guided technique for botulinum toxin injections in the longus colli and capitis muscles. The technique provides clearly identified sonoacoustic/anatomic landmarks that localizes the target muscle and identifies the safest path of the needle to said muscle(s). Toxins 2020, 12, 626; doi:10.3390/toxins12100626 www.mdpi.com/journal/toxins Toxins 2020, 12, 626 2 of 10 Toxins 2020, 12, x FOR PEER REVIEW 2 of 10 1. Introduction Dystonia isis a neurologicala neurological movement movement disorder disorder in which in sustainedwhich sustained or repetitive or musclerepetitive contractions muscle resultcontractions in twisting result and in repetitivetwisting and movements repetitive or abnormalmovements fixed or postureabnormal [1 ].fixed Cervical posture Dystonia [1]. Cervical (CD) is theDystonia most common(CD) is the focal most dystonia common with focal a reported dystonia prevalence with a rangingreported up prevalence to 4100 cases ranging per million up to with4100 ancases incidence per million of 8–12 with cases an incidence per million of person-years8–12 cases per [2 million]. person-years [2]. The symptoms of CD include abnormal neck postures, involuntary head and neck movements, tremor, neckneck pain,pain, andand eveneven involvedinvolved muscularmuscular hypertrophyhypertrophy [[3].3]. CD can be associatedassociated with similar dystonic symptoms symptoms in in nearby nearby muscles, muscles, such such as those as those in the in shoulder, the shoulder, upper upper back and/or back and face./or These face. Thesesymptoms symptoms often have often a have debilitating a debilitating impact impact on an onindividual’s an individual’s function function and quality and quality of life. of life. EEffectiveffective management management of of CD CD requires requires a thoughtful a thoughtful physical physical examination examination of the of head the headand neck and neckmusculature, musculature, observation observation of involuntary of involuntary movements movements and postures, and postures, and patient and patientreport of report muscle of musclepulling, pulling,tightness tightness and pain. and This pain. evaluation This evaluation helps to guide helps muscle to guide selec muscletion for selection targeted for treatment. targeted treatment.Predominant Predominant movement movement patterns patternsare used are to used subtype to subtype CD CDinto into torticollis torticollis (neck/head (neck/head turning), turning), laterocollis (tilting),(tilting), anterocollis anterocollis (Figure (Fig1urea), anterocaput1a), anterocaput (Figure 1(Figb) (neckure or1b) head (neck flexion, or head respectively), flexion, orrespectively), retrocollis/retrocaput or retrocollis/retrocapu (neck/head extension)t (neck/head and or lateralextension) shift (combinationand or lateral of shift laterocollis (combination to one side of andlater laterocaputocollis to one to the side opposite and latero side)caput [4,5]. Patientsto the mayopposite also haveside) a[4,5 combination]. Patients of may these also postures have [ 6a] (Figurecombination1c, Video of these S1). Predominantpostures [6] (Fig anterocollisure 1c, Video occurs S1 in). 25%Predominant of those with anterocollis cervical dystoniaoccurs in [ 725%]. of those with cervical dystonia [7]. (a) (b) (c) Figure 1. Clinical patterns of cervical dystonia. ( (aa)) anterocollis; anterocollis; ( (b) anterocapitis; anterocapitis; ( c) c combinedombined pattern of anterocollis and retrocapitis.retrocapitis. The gold standard of treatment for focal dystonias, including CD, is botulinum toxin (BoNT). The effifficacycacy ofof BoNTBoNT treatmenttreatment dependsdepends onon aa numbernumber ofof factorsfactors includingincluding properproper musclemuscle selectionselection based on patient presentation. The more complex the cervical dystonia, the more difficult difficult the muscle selection [[8].8]. The seven (or(or eight)eight) known serotypes of botulinum toxin are neurotoxins produced by the Clostridium botulinum botulinum bacterium, bacterium, all all of which of which act at act presynaptic at presynaptic neuromuscular neuromuscular (NMJ) (NMJ)and neuro and- neuro-glandularglandular junctions junctions to block to block the therelease release of ofneurotransmitters neurotransmitters (acetylcholine (acetylcholine and and othe others)rs) from presynaptic vesiclesvesicles [9[9,10,10].]. When When injected injected in in muscle, muscle, BoNTs BoNTs decrease decrease the the release release of acetylcholineof acetylcholine at the at NMJ,the NMJ, producing producing graded graded/dose/dose-dependent,-dependent, reversible, reversible, denervation denervation weakness weakness [11 ].[11]. The The mechanism mechanism of actionof action in relievingin relieving dystonia dystonia symptoms symptoms is not is not solely sol dueely due to its to weakening its weakening effects effects on muscle. on muscle. BoNTs BoNTs also havealso have effects effects on various on various central central and peripheral and peripheral pathways pathways implicated implicated in the pathogenesis in the pathogenesis of dystonia. of Thedystonia. efficacy The of efficacy BoNT is of well-documented BoNT is well-documented in the literature in the for literature the treatment for the of treatment muscle overactivity of muscle syndromes,overactivity includingsyndromes, CD including with satisfactory CD with symptom satisfactory relief symptom in approximately relief in approximately 80%–85% of cases 80% [12–85%,13]. Bothof cases the e[12,13fficacy]. andBoth safety the efficacy of BoNT and therapy safety is largelyof BoNT dependent therapy is on largely delivery dependent of BoNT into on thedelivery affected of musclesBoNT into contributing the affected to dystonic muscles postures contributing/movements to dystonic while avoidingpostures/movements untargeted muscles while andavoiding other structures.untargeted Accuratelymuscles and placing other BoNTstructures. within Accurately a muscle while placing avoiding BoNT otherwithin structures a muscle relies while heavily avoiding on accessibilityother structures of the relies muscle heavily which on isaccessibility directly influenced of the muscle by regional which anatomy.is directly To influenced increase the by accuracyregional andanatomy. safety To of increase injections, the cliniciansaccuracy and utilize safet ay number of injections, of localization clinicians techniquesutilize a number including of localization anatomic techniques including anatomic landmarks, palpation, range of motion, electromyography (EMG), Toxins 2020, 12, 626 3 of 10 landmarks, palpation, range of motion, electromyography (EMG), electrical stimulation (E-Stim)