Dysphagia in cervical dystonia patients receiving optimised botulinum toxin therapy: a single-center retrospective cohort study

Treatment response to onabotulinumtoxinA in cervical dystonia patients with anterocollis and retrocollis

Anterocollis (AC) and retrocollis (RC) are less common cervical dystonia (CD) subtypes that are often under-represented in CD clinical trials. Herein we describe real-world demographics, disease characteristics, and treatment response to onabotulinumtoxinA (onabotA) in AC or RC patients from an observational, multicenter, prospective registry, CD PROBE. After three onabotA treatments, outcomes (CDIP-58, PGIC, CGIC, CD severity, TWSTRS) in patients with predominant AC or RC were compared to torticollis (TC) and all CD subtypes combined. The mean dosages at each treatment ranged from 153.5 to 195.4 U (AC) to 184.0-213.4 U (RC). After treatment, AC and RC patients reported improvements in the CDIP-58. "Much" or "very much improved" on PGIC and CGIC was reported by AC patients (n = 11/23, 48%) and clinicians (n = 14/23, 61%); and by RC patients (n = 14/24, 58%) and clinicians (n = 19/24, 83%). The mean total TWSTRS decreased from 45.7 (n = 59) to 36.1 (n = 23, 21.0% improvement) for AC patients and from 40.1 (n = 55) to 31.6 (n = 23, 21.2% improvement) for RC patients; the proportion of AC and RC patients with severe CD decreased. Outcomes for AC and RC were generally consistent with those for TC and all subtypes combined. Dysphagia was reported in 4/59 (6.8%) of AC patients (one serious), 7/55 (12.7%) of RC patients (none serious), 29/494 (5.9%) of TC patients (none serious), and 64/1012 (6.3%) of all CD patients (two serious). No new safety signals were identified. In conclusion, treatment with onabotA may relieve CD symptoms in some patients with AC and RC, consistent with results for other CD subtypes and the known safety profile of onabotA for the treatment of CD.

Comparison of Oropharyngeal Dysphagia Before and After Botulinum Toxin Injection in Cervical Dystonia

Cervical dystonia (CD) is the most common form of focal dystonia with Botulinum neurotoxin (BoNT) being a frequent method of treatment. Dysphagia is a common side effect of BoNT treatment for CD. Instrumental evaluation of swallowing in CD using standardized scoring for the videofluoroscopic swallowing study (VFSS) and validated and reliable patient-reported outcomes measures is lacking in the literature. (1) to determine if BoNT injections change instrumental findings of swallowing function using the Modified Barium Swallow Impairment Profile (MBSImP) in individuals with CD; (2) to determine if BoNT injections change self-perception of the psychosocial handicapping effects of dysphagia in individuals with CD, using the Dysphagia Handicap Index (DHI); (3) to determine the effect of BoNT dosage on instrumental swallowing evaluation and self-reported swallowing outcomes measures. 18 subjects with CD completed a VFSS and the DHI before and after BoNT injection. There was a significant increase in pharyngeal residue for pudding consistency after BoNT injection, p = 0.015. There were significant positive associations between BoNT dosage and self-perception of the physical attributes of the handicapping effect of dysphagia, the grand total score and patient self-reported severity of dysphagia on the DHI; p = 0.022; p = 0.037; p = 0.035 respectively. There were several significant associations between changes in MBSImP scores and BoNT dose. Pharyngeal efficiency of swallowing may be affected by BoNT for thicker consistencies. Individuals with CD perceive greater physical handicapping effects of dysphagia with increased amounts of BoNT units and have greater self-perceptions of dysphagia severity with increased amounts of BoNT units.

Retroform Cervical Dystonia: Target Muscle Selection and Efficacy of Botulinum Toxin Injection

Introduction

Retroform cervical dystonia (RCD), which includes retrocaput and retrocollis, is a rare form of cervical dystonia. Few reports have been published on RCD. The present study aimed to characterize the target muscles involved in RCD and the efficacy of botulinum toxin type A (BTX-A) injection.

Methods

Patients with consecutive cervical dystonia with RCD as the most problematic feature were retrospectively analyzed over a 10-year period. Target muscles were screened and confirmed based on clinical evaluation, single-photon emission computed tomography, and electromyography. In addition, efficacy and adverse events following BTX-A injection in patients with RCD were evaluated.

Results

A total of 34 patients with RCD were included, 18 of whom presented with retrocaput and 16 with retrocollis. The most frequently injected muscles in RCD were splenius capitis (SPCa, 97.1%) and semispinalis capitis (SSCa, 97.1%), followed by levator scapulae (LS, 50.0%), rectus capitis posterior major (RCPM, 47.1%), trapezius (TPZ, 41.2%), and sternocleidomastoid muscle (SCM, 41.2%). Besides cervical muscles, the erector spinae was also injected in 17.6% of patients. Most muscles were predominantly bilaterally injected. The injection schemes of retrocaput and retrocollis were similar, possibly because in patients with retrocollis, retrocaput was often combined. BTX-A injection achieved a satisfactory therapeutic effect in RCD, with an average symptom relief rate of 69.0 ± 16.7%. Mild dysphagia (17.6%) and posterior cervical muscle weakness (17.6%) were the most common adverse events.

Conclusion

SPCa, SSCa, LS, RCPM, LS, and SCM were commonly and often bilaterally injected in RCD. Patients with RCD could achieve satisfactory symptom relief after BTX-A injection.

The Role of Ultrasound for the Personalized Botulinum Toxin Treatment of Cervical Dystonia

The visualization of the human body has frequently been groundbreaking in medicine. In the last few years, the use of ultrasound (US) imaging has become a well-established procedure for botulinum toxin therapy in people with cervical dystonia (CD). It is now undisputed among experts that some of the most relevant muscles in this indication can be safely injected under visual US guidance. This review will explore the method from basic technical considerations, current evidence to conceptual developments of the phenomenology of cervical dystonia. We will review the implications of introducing US to our understanding of muscle function and anatomy of common cervical dystonic patterns. We suggest a flow chart for the use of US to achieve a personalized treatment of people with CD. Thus, we hope to contribute a resource that is useful in clinical practice and that stimulates the ongoing development of this valuable technique.

Botulinum toxin therapy of dystonia

Botulinum toxin (BT) is used to treat a large number of muscle hyperactivity syndromes. Its use in dystonia, however, is still one of the most important indications for BT therapy. When BT is injected into dystonic muscles, it produces a peripheral paresis which is localised, well controllable and follows a distinct and predictable time course of around 3 months. Adverse effects are always transient and usually mild, long-term application is safe. With this profile BT can be used to treat cranial dystonia, cervical dystonia and limb dystonia including writer's and musician's cramps. The recent introduction of BT high dose therapy also allows to treat more wide-spread dystonia including segmental and generalised dystonia. BT can easily be combined with other anti-dystonic treatments such as deep brain stimulation and intrathecal baclofen application. Best treatment results are obtained when BT therapy is integrated in the multimodal and long-term 'multilayer concept of treatment of dystonia'. The biggest challenge for the future will be to deliver state of the art BT therapy to all dystonia patients in need, regardless of whether they live in developed countries or beyond.

Ultrasound Study to Validate the Anterior Cervical Approach to the Longus Colli Muscle Using Electromyography Control Alone

Background:

One of the main difficulties in the treatment of dystonic anterocollis is the injection of the deep flexor muscles of the neck such as Longus Colli (LCo). The injection of the LCo has been regarded as difficult and potentially dangerous; since we published our anterior median approach, a number of questions about the precision and the safety of our technique have been raised by colleagues.

Methods:

7 patients with anterocollis were injected, using our injection technique and when the needle was deemed to be in place, we used the ultrasound probe to determine what the needle had passed through, the depth of the tip of the needle and if the identified muscle was indeed LCo.

Results:

On the ultrasound section the LCo muscle is between 24 and 28 mm deep in the patients examined in this study. The location of the needle was confirmed by ultrasound and in most cases the needle was placed in the right axis but sometimes not deep enough. The EMG control made it possible to correct the depth in all cases. In most of the injections the needle traversed the thyroid. No acute incident occurred by this route of injection. Injections were performed between 22 and 28 mm deep.

Discussion:

From this study and based on a review of complications over 9 years experience with injecting LCo under EMG control using an anterior approach, we conclude that this technique is precise, safe and well tolerated.

Summary (Highlights):

The injection of the Longus Coli muscle for anterocollis has been regarded as difficult and potentially dangerous. This study showed, using ultrasound to determine the needle trajectory, that the anterior approach using EMG control is a precise, safe and well tolerated technique.

AbobotulinumtoxinA using 2-mL dilution (500 U/2-mL) maintains durable improvement across multiple treatment cycles

Background

Cervical dystonia (CD), the most common focal dystonia, is a chronic neurological movement disorder characterized by sustained involuntary contractions of the neck muscles, leading to abnormal postures. AbobotulinumtoxinA (aboBoNT-A) was approved in the US initially as a 500 U per 1-mL dilution and subsequently, as a 500 U/2-mL dilution (or 250 U/mL), thereby providing clinicians with more flexible dosing options to better meet individual patient needs. The objective of this open-label extension study was to evaluate the longer term safety and efficacy of repeat treatments with aboBoNT-A using 2-mL dilutions in adults with cervical dystonia.

Methods

Patients (N = 112) from a 12-week, double-blind lead-in study (NCT01753310) received up to three additional treatments of aboBoNT-A, with re-treatment every 12–16 weeks based on clinical judgment. Safety was assessed through treatment-emergent adverse events (TEAEs). The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total and subscale scores were measured at day 1 of each treatment cycle (C), 4 weeks after each treatment, and 12 weeks after the third treatment. Descriptive statistics were used for all analyses.

Results

In cycles 1, 2, 3, and 4, respectively, 35.7, 25.9, 30.2, and 22.8% of patients reported TEAEs. Dysphagia, muscular weakness, and neck pain were each reported by 10.7% of patients, over the full study duration. Mean TWSTRS total score decreased from 37.7 (SD 13.6 [C1, day 1]) to 30.1 (SD 12.8 [C3, week 12]). In each cycle, TWSTRS total and subscale scores decreased from day 1 to week 4 and increased between weeks 4 and 12, though the week 12 scores remained lower than day 1 scores.

Conclusion

Extended treatment of cervical dystonia with aboBoNT-A (up to 3 additional treatment cycles) using a 2-mL dilution is effective, with a positive risk-benefit profile.

Trial registration

ClinicalTrials.gov Identifier: NCT01753336. Registered 17 Dec 2012.