The effects of botulinum toxin injections into the cricopharyngeus muscle of patients with cricopharyngeus dysfunction associated with pharyngo-laryngeal weakness

Ultrasound-Guided Botulinum Neurotoxin Injection for Alleviating Cricopharyngeus Muscle Spasticity: A Cadaveric Feasibility Study with Nerve Ending Analysis

Botulinum neurotoxin (BNT) injection into the cricopharyngeus muscle (CPM) under ultrasound (US) guidance is a minimally invasive technique performed to relieve cricopharyngeal dysphagia by reducing CPM spasticity. This technique is basically accessible only to both lateral sides of the CPM. This cadaveric study aimed to evaluate whether US-guided injection could effectively deliver BNT to abundant areas of gross nerve endings within the CPM. We utilized a newly modified Sihler's staining method to identify regions with abundant neural endings within the CPM while preserving the three-dimensional morphology of the muscle in 10 sides of 5 fresh cadavers. A mixture of 0.2 mL dye was injected into the 16 sides of CPM under US guidance in 8 cadavers. Nerve endings were abundant in posterolateral areas of the CPM; the injected dye was identified at the posterolateral area on 12 sides (12/16 side, 75%) without diffusion into the posterior cricoarytenoid muscle. The injection failed on four sides (two sides of the prevertebral fascia and two sides of the esophagus below the CPM). These results suggest that US-guided injection could be a feasible technique as it can deliver BNT to the most abundant nerve distribution areas within the CPM in most cases.

Guidelines for the Use of Botulinum Toxin in Otolaryngology From the Korean Society of Laryngology, Phoniatrics and Logopedics Guideline Task Force

The Korean Society of Laryngology, Phoniatrics and Logopedics created a task force to establish clinical practice guidelines for the use of botulinum toxin (BT) in otolaryngology. We selected 10 disease categories: spasmodic dysphonia, essential vocal tremor, vocal fold granuloma, bilateral vocal fold paralysis, Frey's syndrome, sialocele, sialorrhea, cricopharyngeal dysfunction, chronic sialadenitis, and first bite syndrome. To retrieve all relevant papers, we searched the CORE databases with predefined search strategies, including Medline (PubMed), Embase, the Cochrane Library, and KoreaMed. The committee reported 13 final recommendations with detailed evidence profiles. The guidelines are primarily aimed at all clinicians applying BT to the head and neck area. In addition, the guidelines aim to promote an improved understanding of the safe and effective use of BT by policymakers and counselors, as well as in patients scheduled to receive BT injections.

Botulinum Toxin Injection for the Treatment of Upper Esophageal Sphincter Dysfunction

Dysphagia associated with upper esophageal sphincter (UES) dysfunction remarkably affects the quality of life of patients. UES injection of botulinum toxin is an effective treatment for dysphagia. In comparison with skeletal muscles of the limb and trunk, the UES is a special therapeutic target of botulinum toxin injection, owing to its several anatomical, physiological, and pathophysiological features. This review focuses on (1) the anatomy and function of the UES and the pathophysiology of UES dysfunction in dysphagia and why the entire UES rather than the cricopharyngeal muscle before/during botulinum toxin injection should be examined and targeted; (2) the therapeutic mechanisms of botulinum toxin for UES dysfunction, including the choice of injection sites, dose, and volume; (3) the strengths and weaknesses of guiding techniques, including electromyography, ultrasound, computed tomography, and balloon catheter dilation for botulinum toxin injection of the UES.

The Effect of Combined Guidance of Botulinum Toxin Injection with Ultrasound, Catheter Balloon, and Electromyography on Neurogenic Cricopharyngeal Dysfunction: A Prospective Study

BACKGROUND

Cricopharyngeal botulinum toxin (BTX) injection is one of the treatments for neurogenic cricopharyngeal dysfunction (CPD). We conducted this prospective study to investigate the effect and safety of BTX injection for neurogenic CPD with a novel guidance.

METHODS

Twenty-one patients with neurogenic CPD whose symptoms did not reduce after conventional swallowing therapy were included in this study. The impact of BTX injection on the swallowing function of the patients was evaluated.

KEY RESULTS

After the injection, the Functional Oral Intake Scale (FOIS) score increased in 17 of 21 patients (80.9%), which ranged from 1 to 3 (P < 0.001). Moreover, there was a significant reduction in the UES opening impairment (P < 0.01), UES residual pressure (P < 0.05), duration of UES relaxation, penetration-aspiration scale score (P < 0.05), secretion (P < 0.05), vallecular residue (P < 0.01), and left (P < 0.05) and right (P < 0.05) pyriform sinus residue. With at least 6 months of follow-up, we found that FOIS continued to increase in patients who showed improvement after the injection (i.e., FOIS 5-7 points), while it remained unchanged in patients without improvement after the injection. There were no side effects reported in this study.

CONCLUSION & INFERENCES

BTX injection into the cricopharyngeal muscle guided by ultrasound, catheter balloon, and electromyography possibly has a long-lasting effect that can effectively and safely improve the swallowing function of patients with neurogenic CPD.

Dysphagia in Lateral Medullary Syndrome: A Narrative Review

Dysphagia is a common clinical feature of lateral medullary syndrome (LMS) and is clinically relevant because it is related to aspiration pneumonia, malnutrition, increased mortality, and prolonged hospital stay. Herein, the pathophysiology, prognosis, and treatment of dysphagia in LMS are reviewed. The pathophysiology, prognosis, and treatment of dysphagia in LMS are closely interconnected. Although the pathophysiology of dysphagia in LMS has not been fully elucidated, previous studies have suggested that the medullary central pattern generators coordinate the pharyngeal phases of swallowing. Investigation of the extensive neural connections of the medulla oblongata is important in understanding the pathophysiologic mechanism of dysphagia in LMS. Previous studies have reported that most patients with dysphagia in LMS have a relatively good prognosis. However, some patients require tube feeding for several months, even years, due to severe dysphagia, and little has been reported about conditions associated with a poor prognosis of dysphagia in LMS. Concerning specific therapeutic modalities for dysphagia in LMS, in addition to general modalities used for dysphagia treatment in stroke patients, non-invasive modalities, including repetitive transcranial magnetic stimulation and transcranial direct current stimulation, as well as invasive modalities, such as botulinum toxin injection, balloon catheter dilatation, and myotomy for relaxation of the cricopharyngeal muscle, have been applied. For the appropriate application of therapeutic modalities, clinicians should be aware of the recovery mechanisms and prognosis of dysphagia in LMS. Further studies on this topic, as well as studies involving large numbers of subjects on specific therapeutic modalities, should be encouraged.

Use of the Penetration-Aspiration Scale in Dysphagia Research: A Systematic Review

The penetration-aspiration scale (PAS) is an 8-point scale used to characterize the depth and response to airway invasion during videofluoroscopy. Though widely used in the field of deglutition, there is a lack of consensus regarding the statistical properties of the scale. In order to better understand the state of the literature and the statistical use of the PAS, a systematic review was undertaken to descriptively examine trends in statistical and reporting practices of the PAS since its inception. Online databases were searched for studies citing the original PAS article, which yielded 754 unique articles. Of these, 183 studies were included in the review. Results showed inconsistencies in the statistical use of the scale; 79 studies treated the PAS as ordinal, 71 as categorical, and 49 as interval. Ten types of categorizations were identified. Reporting of power analyses (9%), as well as inter- (26%) and intra-rater (17%) reliability, was uncommon. Among studies that administered multiple bolus volumes or consistencies, 55% reported PAS analyses at the participant/group level only. This review confirms the existence of discrepancies in the statistical treatment of the PAS. A lack of consensus among researchers limits comparisons between studies. The approach to handling this scale dictates the statistical tests used, potentially affecting results and interpretations. Consistent application of statistically sound approaches to PAS analyses is vital for the future of deglutition research.

Inter-rater reliability of seven neurolaryngologists in laryngeal EMG signal interpretation

Purpose

Laryngeal electromyography (LEMG) has been considered as gold standard in diagnostics of vocal fold movement impairment, but is still not commonly implemented in clinical routine. Since the signal interpretation of LEMG signals (LEMGs) is often a subjective and semi-quantitative matter, the goal of this study was to evaluate the inter-rater reliability of neurolaryngologists on LEMGs of volitional muscle activity.

Methods

For this study, 52 representative LEMGs of 371 LEMG datasets were selected from a multicenter registry for a blinded evaluation by 7 experienced members of the neurolaryngology working group of the European Laryngological Society (ELS). For the measurement of the observer agreement between two raters, Cohen’s Kappa statistic was calculated. For the interpretation of agreements of diagnoses among the seven examiners, we used the Fleiss’ Kappa statistic.

Result

When focusing on the categories “no activity”, “single fiber pattern”, and “strongly decreased recruitment pattern”, the inter-rater agreement varied from Cohen’s Kappa values between 0.48 and 0.84, indicating moderate to near-perfect agreement between the rater pairs. Calculating with Fleiss’ Kappa, a value of 0.61 showed good agreement among the seven raters. For the rating categories, the Fleiss’ Kappa value ranged from 0.52 to 0.74, which also showed a good agreement.

Conclusion

A good inter-rater agreement between the participating neurolaryngologists was achieved in the interpretation of LEMGs. More instructional courses should be offered to broadly implement LEMG as a reliable diagnostic tool in evaluating vocal fold movement disorders in clinical routine and to develop future algorithms for therapy and computer-assisted examination.

Botulinum Toxin Injection in the Treatment of Postextubation Dysphagia: A Case Report

Prolonged intubation is known to bring on postextubation dysphagia (PED) in some patients. We have noted that there were some studies to investigate specific type and pattern of PED, which showed large variety of different swallowing abnormalities as mechanisms of PED that are multifactorial. There are several options of treatment in accordance with the management of these abnormalities. A botulinum toxin (BoT) injection into the upper esophageal sphincter (UES) can improve swallowing functions for patients with this disorder, by working to help the muscle relax. In this case, the conventional treatment was not effective in patients with PED, whereas the BoT injection made a great improvement for these patients. This study suggests that the UES pathology could be the main cause of PED.

Office-based Electromyography-guided Botulinum Toxin Injection to the Cricopharyngeus Muscle: Optimal Patient Selection and Technique

Objectives:

This retrospective study was carried out to investigate the effectiveness and safety of office-based electromyography-guided injection of botulinum toxin in the cricopharyngeus muscle of patients who did not show upper esophageal sphincter passage in a swallowing study in spite of maximal swallowing rehabilitation.

Methods:

Thirty-six patients who showed no or limited ability to oral feed after maximum swallowing rehabilitation were enrolled. Video fluoroscopic swallowing study, flexible endoscopic evaluation of swallowing, disability rating scale, penetration aspiration score, and National Institutes of Health swallowing safety scale were used in the evaluation of dysphagia.

Results:

Success was defined as nondependence on gastrostomy for patients who previously were dependent on gastrostomy and improvement in disability rating scale score after botulinum toxin injections. The total success rate was 63.9%. The complication rate was very low, with only 1 patient showing temporary unilateral vocal fold paralysis. Botulinum toxin injection was more effective in patients with cranial nerve IX or X palsy than in those without it ( P = .006).

Conclusions:

This procedure can be a simple, safe, and effective tool in patients with cricopharyngeal dysfunction after swallowing rehabilitation, especially for cranial nerve IX or X palsy.

Botulinum Toxin Is Effective in the Management of Neurogenic Dysphagia. Clinical-Electrophysiological Findings and Tips on Safety in Different Neurological Disorders

Background and Aims: Neurogenic dysphagia linked to failed relaxation of the upper esophageal sphincter (UES) can be treated by injecting botulinum toxin (BTX) into the cricopharyngeal (CP) muscle. We compared the effects of this treatment in different neurological disorders with dysphagia, to evaluate its efficacy over time including the response to a second injection. Materials and Methods: Sixty-seven patients with neurogenic dysphagia associated with incomplete or absent opening of the UES (24 with brainstem or hemispheric stroke, 21 with parkinsonian syndromes, 12 with multiple sclerosis, and 10 with spastic-dystonic syndromes secondary to post-traumatic encephalopathy) were treated with the injection of IncobotulinumtoxinA (dose 15-20 U) into the CP muscle under electromyographic guidance. The patients were assessed at baseline and after the first and second treatment through clinical evaluation and fiberoptic endoscopy of swallowing, while their dysphagia was quantified using the Dysphagia Outcome and Severity Scale (DOSS). An electrokinesiographic/electromyographic study of swallowing was performed at baseline. Results: Most patients responded to the first BTX treatment: 35 patients (52.2%) were classified as high responders (DOSS score increase >2 levels), while other 19 patients (28.4%) were low responders (DOSS score increase of ≤2 levels). The effect of the first treatment usually lasted longer than 4 months (67%), and in some cases up to a year. The treatment efficacy remained high also after the second injection: 31 patients (46.3%) qualified as high responders and other 22 patients (32.8%) showed a low response. Only in the parkinsonian syndromes group we observed a reduction in the percentage of high responders as compared with the first treatment. Side effects were mostly mild and reported in non-responders following the first injection. A severe side effect, consisting of ingestion pneumonia, was observed following the second BTX injection in two patients who had both been non-responders to the first. Non-responders were characterized electromyographically by higher values of the oropharyngeal interval. Conclusion: These findings confirm the effectiveness of IncobotulinumtoxinA injection in the treatment of neurogenic dysphagia due to hyperactivity and relaxation failure of the UES. Caution should be used as regards, the re-injection in non-responders to the first treatment.

Botulinum toxin injection in laryngeal dyspnea

Data, regarding the use of botulinum toxin (BT-A) in laryngeal dyspnea, are scarce, coming from some cases reports in the literature, including Vocal fold paralysis, laryngeal dystonia, vocal cord dysfunction also called paradoxical motion of the vocal fold (PMVF), and post-neuroleptic laryngeal dyskinesia. There is no consensus regarding the muscles and the doses to inject. The aim of this study is to present a retrospective review of patients treated in our ENT Department by BT-A injection in this indication. This study is a retrospective study describing patients who underwent an injection of botulinum toxin for laryngeal dyspnea in the ENT Department from 2005 to 2015 years. The inclusion criteria were a dyspnea associated with a laryngeal dysfunction, confirmed by flexible fiberoptic nasopharyngolaryngoscopy. Information concerning the causes of the dyspnea, the botulinum toxin BT-A injections procedure, post-injection follow-up, and respiratory outcome were collected for all patients included. In the group of 13 patients included, the main cause identified as principal factor linked with the short breath was: a bilateral VF paralysis (Patel et al., Otolaryngol Head Neck Surg 130:686-689, 7), laryngeal dystonia (Balkissoon and Kenn, Semin Respir Crit Care Med 33:595-605, 2), Anxiety syndrome associated with unilateral vocal fold paralysis or asthma (Marcinow et al., Laryngoscope 124:1425-1430, 3), and an isolated asthma (Zwirner et al., Eur Arch Otorhinolaryngol 254:242-245, 1). Nine out of the thirteen patients were improved by the injections. A BT-A-induced stable benefit for four patients led them to stop the injections in the follow-up. Good outcome was observed in five other patients (main cause: bilateral VP paralysis), allowing a progressive lengthening of the delay between BT-A injections. Four patients did not report a positive risk/benefit ratio after BT-A injections; two of them (with bilateral VF paralysis), because of respiratory side effects and lack of benefit without the side effects for the two others. This failure of effect was not related with BT-A doses injected. This study provides support for using BT-A injections as a symptomatic treatment of periodic laryngeal dyspnea, regardless of the etiologic context. From our data, we suggest that a small starting dose (of around 4 U BT-A Botox^®) could be enough for a first injection to obtain a good benefit. The target muscle should be determined by the EMG analysis.

Dysphagia Post Subcortical and Supratentorial Stroke

BACKGROUND

Studies have recognized that the damage in the subcortical and supratentorial regions may affect voluntary and involuntary aspects of the swallowing function. The current study attempted to explore the dysphagia characteristics in patients with subcortical and supratentorial stroke.

METHODS

Twelve post first or second subcortical and supratentorial stroke patients were included in the study. The location of the stroke was ascertained by computed tomography and magnetic resonance imaging. The characteristics of swallowing disorder were assessed by video fluoroscopic swallowing assessment/fiberoptic endoscopic evaluation of swallowing. The following main parameters were analyzed: oral transit time, pharyngeal delay time, presence of cricopharyngeal muscle achalasia (CMA), distance of laryngeal elevation, the amounts of vallecular residue and pyriform sinus residue (PSR), and the extent of pharyngeal contraction.

RESULTS

Eighty-three percent of the 12 patients were found suffering from pharyngeal dysphagia, with 50% having 50%-100% PSRs, 50% having pharyngeal delay, and 41.6% cases demonstrating CMA. Simple regression analysis showed PSRs were most strongly associated with CMA. Pharyngeal delay in the study can be caused by infarcts of basal ganglia/thalamus, infarcts of sensory tract, infarcts of swallowing motor pathways in the centrum semiovale, or a combination of the three.

CONCLUSION

Subcortical and supratentorial stroke may result in pharyngeal dysphagia such as PSR and pharyngeal delay. PSR was mainly caused by CMA.

Endoscopic-guided injection of botulinum toxin into the cricopharyngeus muscle: our experience

Objective:

To assess the efficacy of endoscopic-guided botulinum toxin injection into the cricopharyngeus muscle and evaluate the duration of its effects.

Methods:

A 3-year prospective study of 12 patients undergoing injection of botulinum toxin was conducted, with a telephone survey to assess dysphagia pre-operatively, and at 1, 3 and 6 months post-treatment, using the MD Anderson Dysphagia Inventory.

Results:

Median age was 66.2 years. Causes of cricopharyngeal dysphagia included idiopathic cricopharyngeal hypertrophy (67 per cent), previous cerebrovascular accident (17 per cent), cranial nerve palsy (8 per cent) and previous chemoradiotherapy to the neck (8 per cent). There were no complications. Two patients had repeat injections after six months. There was significant improvement in MD Anderson Dysphagia Inventory scores at one and three months versus pre-operative scores (73.1 ± 14.9 vs 46.9 ± 7.6, p = 0.0001, and 65.1 ± 11.5 vs 46.9 ± 7.6, p = 0.0001), but not at six months (51.0 ± 11.0 vs 46.9 ± 7.6, p = 0.14).

Conclusion:

Endoscopic-guided injection of botulinum toxin into the cricopharyngeus muscle is a safe and effective method for treating cricopharyngeal muscle dysfunction, lasting up to six months.

Cricopharyngeal dysfunction: A systematic review comparing outcomes of dilatation, botulinum toxin injection, and myotomy

OBJECTIVES

Cricopharyngeal dysfunction may lead to severe dysphagia and aspiration. The objective of this systematic review was to evaluate the existing studies on the effectiveness of myotomy, dilatation, and botulinum toxin (BoT) injection in the management of cricopharyngeal dysphagia.

METHODS

PubMed and Web of Science databases were searched to identify eligible studies by using the terms "cricopharyngeal dysfunction," "cricopharyngeal myotomy," "cricopharyngeal botox," "cricopharyngeal dilation," and their combinations from 1990 to 2013. This was supplemented by hand-searching relevant articles. Eligible articles were independently assessed for quality by two authors. Statistical analysis was performed.

RESULTS

The database search revealed 567 articles. Thirty-two articles met eligibility criteria and were further evaluated. The reported success rates of BoT injections was between 43% and 100% (mean = 76%), dilation 58% and 100% (mean = 81%), and myotomy 25% and 100% (mean = 75%). In logistic regression analysis of the patient-weighted averages, the 78% success rate with myotomy was significantly higher than the 69% success rate with BoT injections (P = .042), whereas the intermediate success rate of 73% with dilation was not significantly different from that of either myotomy (P = .37) or BoT (P = .42). There was a statistically significant difference between endoscopic and open myotomy success rates (P = .0025). Endoscopic myotomy had a higher success rate, with a 2.2 odds ratio.

CONCLUSIONS

The success rate of myotomy is significantly higher than the success rate of BoT injections in cricopharyngeal dysfunction. Moreover, endoscopic myotomy was found to have a higher success rate compared to open myotomy.

Treatment of cricopharyngeal dysfunction: a comparative pilot study

Background

Cricopharyngeal dysfunction is a narrowing at the level of the upper oesophageal sphincter caused by failed or incomplete sphincter opening as a result of lack of pharyngoesophageal coordination or reduction in the muscular compliance of the upper oesophageal sphincter. Oropharyngeal dysphagia is a typical symptom. Videomanometry allows direct comparison of pressure readings with dynamic anatomy during swallowing.

Methods

This is a prospective randomized pilot study that compares the effect of balloon dilatation and laser myotomy in cricopharyngeal dysfunction. We used videomanometry as an objective measure and the Swedish version of Sydney Swallowing Questionnaire as patient’s self-assessment at baseline and 1 and 6 months after treatment.

Results

The UES sagittal diameter increased from 5.6 mm pre-operatively to 8.4 mm 6 months post-operatively with no differences between treatment groups. Preoperative mean Sydney Swallowing Questionnaire score was 770 and 6 months post-operative score 559, with no difference between the treatments in our cohort.

Conclusion

Cricopharyngeal dysfunction treatment by either laser myotomy or balloon dilatation improved upper oesophageal sphincter opening during at least 6 months.

Trial registration: ISRCTN84905610, date: 081214

Teaching laryngeal electromyography

To achieve consensus in the methodology, interpretation, validity, and clinical application of laryngeal electromyography (LEMG), a working group on neurolaryngology from the European Laryngological Society (ELS) was founded in 2010. The main task of the working group was to teach key techniques like LEMG procedures. The objective of this study was to collect information on the teaching techniques used and describe them. A multicenter registry was created to analyze the data collected from LEMGs in 14 departments. We screened how often different departments participated in teaching events. Teaching events were classified retrospectively: presentations at conferences and meetings; workshops with hands-on training on patients; workshops with hands-on training on animal models; workshops with hands-on training on anatomic specimens; and supervision by experts to perform LEMG together. Both, supervision to perform LEMG together and the total number of PCA-LEMGs (r = 0.713), as well as supervision to perform LEMG together and the PCA/total-number-of-LEMG ratio (r = 0.814) were correlated significantly (p < 0.05). Similarly, the sum of teaching events was correlated significantly with the total number of PCA-LEMGs (r = 0.605), and so did the sum of teaching events with the PCA/total-number-of-LEMG ratio (r = 0.704). Participation in hands-on training in humans was correlated significantly with the PCA/total-number-of-LEMG ratio (r = 0.640). The data presented herein suggest that multimodal teaching techniques are most effective. To promote multimodal learning an interactive webpage ( http://www.lemg.org) providing videos and animations, and the possibility to discuss cases with other experts was established.

Botulinum toxin injection for hypercontractile or spastic esophageal motility disorders: may high-resolution manometry help to select cases?

Endoscopic injections of botulinum toxin in the cardia or distal esophagus have been advocated to treat achalasia and spastic esophageal motility disorders. We conducted a retrospective study to evaluate whether manometric diagnosis using the Chicago classification in high-resolution manometry (HRM) would be predictive of the clinical response. Charts of patients with spastic and hypertensive motility disorders diagnosed with HRM and treated with botulinum toxin were retrospectively reviewed at two centers. HRM recordings were systematically reanalyzed, and a patient's phone survey was conducted. Forty-five patients treated between 2008 and 2013 were included. Most patients had achalasia type 3 (22 cases). Other diagnoses were jackhammer esophagus (8 cases), distal esophageal spasm (7 cases), esophagogastric junction outflow obstruction (5 cases), nutcracker esophagus (1 case), and 2 unclassified cases. Botulinum toxin injections were performed into the cardia only in 9 cases, into the wall of the distal esophagus in 19 cases, and in both locations (cardia and distal esophagus) in 17 cases. No complication occurred in 31 cases. Chest pain was noticed for less than 7 days in 13 cases. One death related to mediastinitis occurred 3 weeks after botulinum toxin injection. Efficacy was assessed in 42 patients: 71% were significantly improved 2 months after botulinum toxin, and 57% remained satisfied for more than 6 months. No clear difference was observed in terms of response according to manometric diagnosis; however, type 3 achalasia previously dilated and with normal integrated relaxation pressure (4s-integrated relaxation pressure < 15 mmHg) had the worst outcome: none of these patients responded to the endoscopic injection of botulinum toxin. Endoscopic injections of botulinum toxin may be effective in some patients with spastic or hypercontractile esophageal motility disorders. The manometric Chicago classification diagnosis does not seem to predict the results. Prospective randomized trials are required to identify patients most likely to benefit from esophageal botulinum toxin treatment.

Botulinum toxin for upper oesophageal sphincter dysfunction in neurological swallowing disorders

BACKGROUND

Adequate upper oesophageal sphincter (UOS) opening is critical to safe and efficient swallowing due to the close proximity of the UOS to the airway entrance. Many people with neurological conditions, progressive and non-progressive, present with UOS dysfunction. The consequences for the person include difficulty swallowing food with subsequent choking and aspiration (passage of material into the trachea beyond the level of the true vocal cords). Clinical complications include aspiration pneumonia, weight loss, dehydration and malnutrition. Tube feeding is often indicated but is associated with increased mortality. Quality of life is also frequently impacted. A range of interventions exist that aim to improve UOS function and swallowing. These include compensatory strategies, rehabilitation techniques, pharmacological interventions and surgery. Over the last two decades, botulinum toxin has been gaining popularity as an intervention for UOS dysfunction, with some evidence to suggest that it is successful in improving swallow function. Despite a number of studies investigating its efficacy, there is a lack of consensus regarding whether this intervention is effective in improving swallowing for individuals with UOS dysfunction associated with neurological disease.

OBJECTIVES

To establish the efficacy and safety of botulinum toxin use aimed at improving UOS dysfunction in people with swallowing difficulties (dysphagia) associated with non-progressive and progressive neurological disease.

SEARCH METHODS

We searched the following electronic databases for published trials: the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (1950 to 2013); EMBASE (1980 to 2013); AMED (Allied and Complementary Medicine) (1941 to 2013); CINAHL (Cumulative Index to Nursing and Allied Health Literature) (1937 to 2013). We also searched major clinical trials registers: CCT (http://www.controlled-trials.com); Clinical Trials (http://www.clinicaltrials.gov); Chinese Clinical Trial Register (www.chictr.org); ACTR (http://www.actr.org.au/. We examined the reference lists of all potentially relevant studies to identify further relevant trials. We handsearched published abstracts of conference proceedings from both the Dysphagia Research Society and the European Society of Swallowing Disorders. Digestive Disease Week (published in Gastroenterology) was also handsearched. Additionally, we searched ProQuest Dissertations & Theses for dissertation abstracts.

SELECTION CRITERIA

Only randomised controlled trials were sought.

DATA COLLECTION AND ANALYSIS

Independent searches were completed by JR, AM, MC and MW. Two review authors (JR and MW) independently inspected titles, abstracts and key words identified from the literature search.

MAIN RESULTS

No randomised controlled studies were retrieved. Twenty-nine studies were excluded, mainly on the basis of trial design.

AUTHORS' CONCLUSIONS

It was not possible to reach a conclusion on the efficacy and safety of botulinum toxin as an intervention for people with UOS dysfunction and neurological disease. There is insufficient evidence to inform clinical practice. Directions for future research are provided.