Technique for injection of botulinum toxin through the flexible nasolaryngoscope

Treatment Outcome Measures for Spasmodic Dysphonia: A Systematic Review

PURPOSE

This systematic review aims to identify instruments used to evaluate treatment outcomes for people with spasmodic dysphonia.

METHODS

Electronic database (PubMed, Cochrane Library, Embase, and CINAHL) searches and hand-searching identified studies that evaluated treatment approaches for spasmodic dysphonia which included pre and post outcome data.

RESULTS

A total of 4714 articles were retrieved from searching databases; 1165 were duplicates. Titles and abstracts of 3549 were screened, with 171 being selected for full-text review. During full-text review, 101 articles were deemed suitable for inclusion. An additional 24 articles were identified as suitable for inclusion through hand-searching of reference lists. Data was extracted from 125 studies, identifying 220 outcome measures. As per the World Health Organization's International Classification of Functioning (ICF), the majority measured body functions (n = 212, 96%). Outcomes that explored communication and participation in everyday life and attitudes towards communication (ie, activity and participation domains) were infrequent (n = 8; 4%). Quality of life, a paradigm outside of the scope of the ICF, was also captured by four outcome measures. No instruments evaluating communication partners' perspectives were identified.

CONCLUSIONS

Currently there is no unified approach to the measurement of outcomes in SD treatment research. Development and implementation of a core outcome set is recommended to facilitate improved understanding of the efficacy of current and new treatment options.

Chemodenervation of the Larynx

Botulinum neurotoxin (BoNT) has existed for thousands of years; however, it was not medically utilized until investigations into its therapeutic use began in sincerity during the late 1970s and 1980s. This, coupled with the reclassification of spasmodic dysphonia as a focal dystonia, led to the use of chemodenervation for this disorder, which has since become a refined technique. Indeed, due to its safety and efficacy, BoNT has been investigated in multiple neurolaryngology disorders, including spasmodic dysphonia, vocal tremor, and muscle tension dysphonia. BoNT has been shown to be a useful and safe adjunct in the treatment for these disorders and may reduce or eliminate oral pharmacotherapy and/or prevent the need for a surgical intervention. We present the historical background, development, proposed mechanisms of action, uses, and techniques for administering BoNT for laryngeal disorders, with a particular focus on spasmodic dysphonia.

Transnasal Flexible Fiberoptic in-office Laryngeal Biopsies-Our Experience with 117 Patients with Suspicious Lesions

OBJECTIVE

To compare pathologic results obtained via in-office transnasal fiberoptic laryngoscopy (TFL) to those of subsequent direct laryngoscopy in order to assess the accuracy of TFL as a diagnostic tool.

PATIENTS

One hundred and seventeen patients with suspicious laryngeal lesions.

METHODS

All patients underwent in-office biopsies. All patients with malignant diagnosis were referred to treatment. All patients with benign diagnosis or carcinoma in situ were referred to direct laryngoscopy for definitive diagnosis. The pathological results of the specimens from both procedures were compared.

RESULTS

Adequate tissue for diagnostic purposes was obtained in 110 of 117 in-office transnasal fiberoptic laryngoscopy biopsies (94.0%). The biopsy results revealed invasive carcinoma in 42 patients (38.2%), carcinoma in situ (CIS) in 17 patients (15.4%), and benign lesions in 51 patients (46.4%). All patients with benign pathologies and carcinoma in situ were referred to biopsy under direct laryngoscopy (five patients refused and were removed from the statistics). The final pathologies identified from the biopsies on direct laryngoscopy revealed that there was an underestimation of the transnasal fiberoptic laryngoscopy results in 33 patients (a false negative rate of 31.4%, 33/105) and an overestimation in one patient. The sensitivity of transnasal fiberoptic laryngoscopy biopsy compared with direct laryngoscopy biopsy was 70.6% and the specificity was 96.7%.

CONCLUSIONS

TFL with biopsy is easy, safe, and cost-effective but raises serious doubts about its clinical value due to its low sensitivity rate for diagnosing suspicious lesions of the larynx. As such, it is recommended that all patients with a suspicious lesion diagnosed by TFL biopsy as being benign or CIS should be referred to direct laryngoscopy for verification of the findings.

The point-touch technique for botulinum toxin injection in adductor spasmodic dysphonia: quality of life assessment

Background:

Botulinum toxin injection under electromyographic guidance is the ‘gold standard’ for adductor spasmodic dysphonia treatment. The point-touch technique, an alternative injection method which relies on anatomical landmarks, is cheaper, quicker and more accessible, but has not yet gained widespread acceptance due to concerns about patient satisfaction.

Objective:

To assess swallowing and voice-related quality of life following point-touch botulinum toxin injection in adductor spasmodic dysphonia patients.

Setting:

Stanford University Voice and Swallowing Center.

Design:

Prospective case series (evidence level four).

Methods:

Consecutive adductor spasmodic dysphonia patients with a stable botulinum toxin dose–response relationship were recruited prospectively. The Eating Assessment Tool and Voice-Related Quality of Life questionnaires were completed pre-treatment and at 10 and 30 per cent completion of the injection cycle, respectively.

Results:

Thirty-seven patients completed follow up. The mean total botulinum toxin dose was 0.88 units. Pre-treatment Voice-Related Quality of Life questionnaire results reflected the burden of disease. Post-treatment Eating Assessment Tool and Voice-Related Quality of Life questionnaire results were collected at 2.53 and 7.84 weeks, respectively; the former showed an increase in dysphagia, albeit statistically insignificant, while the latter showed significantly improved scores (both domain and total).

Conclusion:

The point-touch technique is a viable alternative for botulinum toxin injection in the treatment of adductor spasmodic dysphonia.

Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.

Evidence for the effectiveness of botulinum toxin for spasmodic dysphonia from high-quality research designs

The practice of evidence-based medicine promotes use of the knowledge ascertained from high quality research designs. The objective of this review was to determine what evidence has been provided from high quality research designs (e.g., randomized control trials or high quality prospective, matched group cohort studies), through December of 2006, relative to the effectiveness of botulinum toxin for treating spasmodic dysphonia. Results of the review indicated that no new high quality (Class I or Class II) studies have been published since 2001. One Class I study has been published since 1973, which found significant treatment effects for acoustic and perceptual variables of vocal function. Four Class II studies have been published during this same time frame, all finding significant treatment effects, though the nature of studied factors was variable between investigations. Based on the quality of evidence scale used, botulinum toxin can be considered an effective treatment for adductor spasmodic dysphonia.

Die Behandlung laryngealer Bewegungsstörungen mit Botulinumtoxinen

Laryngeal dystonia (spasmodic dysphonia) is a movement disorder characterised by involuntary contractions of the laryngeal muscles involved in vocalisation. The introduction of botulinum toxin (BTX) in the treatment of laryngeal dystonia had a major clinical impact due to the striking improvement of symptoms. In general, BTX can be delivered by percutaneous injection or by the transoral route. The subcutaneous method is simple, but the effects of the transoral injection, applied through a curved device or by use of a flexible nasolaryngoscope with a working channel and visual control, might be more effective. However, for various reasons the transoral route does not work in every patient. We report our experiences using these different techniques for the monitoring of patients and their treatment with botulinum toxin in laryngeal movement disorders.

Botulinum toxin A injection under electromyographic guidance for treatment of spasmodic dysphonia

Spasmodic dysphonia is a disabling voice condition caused by a chronic neurological disorder of central motor processing. Present therapy is directed at relief of symptoms rather than cure. Botulinum toxin type A injection into the thyroarytenoid muscle has become the pre-eminent approach for treatment of adductor spasmodic dysphonia. Botulinum toxin A injections can be performed in an out-patient setting under electromyographic guidance. We present our experience with 153 injections in 14 patients with adductor spasmodic dysphonia over a 10-year period. We demonstrate that the electromyography signal is a reliable prognostic indicator in terms of efficacy, and that patients' subjective opinion is a valid indicator of treatment success and future treatment strategy.

[Treatment of laryngeal movement disorders with botulinum toxins: part 1: History and mode of action]

Laryngeal dystonia (spasmodic dysphonia) is a movement disorder characterised by involuntary contractions of the laryngeal muscles involved in vocalisation. The introduction of botulinum toxin (BTX) in the treatment of laryngeal dystonia had a major clinical impact due to the striking improvement of symptoms. Most patients with severe types of spasmodic dysphonia are treated with injections of botulinum toxin type A. For patients with a resistance against type A toxin there is a new hypercleaned type A toxin or type B available. Research on type F toxin is also underway. In this article, the history of botulinum toxin, its therapeutic activity and possibilities for its use are described.

Botulinum toxin therapy of laryngeal muscle hyperactivity syndromes: comparing different botulinum toxin preparations

Spasmodic dysphonia (SD) is a focal dystonia characterized by a strained, strangled voice. Botulinum toxin is a symptomatic treatment for SD and has become the mainstay of therapy over the last two decades. In this manuscript, we briefly review different laryngeal muscle hyperactivity syndromes, their injection techniques and toxins currently available. Adductor SD is the most common indication for botulinum toxin treatment in the larynx. All studies report similar results with regard to improvement, patient satisfaction and side effects. We describe different injection techniques to treat this disorder such as the percutaneous, transoral, transnasal, point-touch techniques. In abductor SD, a subtype of SD, the treatment is aimed at the posterior cricoarytenoid muscle. Other applications of botulinum toxin in the larynx include spasmodic laryngeal dyspnea and voice tremors. We also review injection techniques, the different toxin types used, and toxin doses.

Transnasal, endoscopic vocal fold augmentation

The practice of injection laryngoplasty under local anesthesia has become more common as both the indications for the procedure and the number of injectable substances increased. Modifications to the injection techniques used for vocal fold augmentation have been described over the last decade that reflect changes in the established percutaneous and transoral approaches. These percutaneous and transoral injection techniques for the treatment of dysphonia secondary to glottic incompetence are well described and provide an adequate approach for most cases. However, these traditional methods may be difficult to master, require great patient tolerance, and may be impossible to perform when anatomic or physiologic barriers exist. We describe a new application of the fiberoptic transnasal endoscope to perform laryngeal injection using a flexible needle through a port in the endoscope. This technique is easily mastered and readily tolerated by patients who would not be candidates for the other injection techniques under local anesthesia. We present our favorable experience with this technique and identify its shortcomings coupled with recommendations to address future technical modifications.

Speech intelligibility in severe adductor spasmodic dysphonia

This study compared speech intelligibility in nondisabled speakers and speakers with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (Botox) injection. Standard speech samples were obtained from 10 speakers diagnosed with severe ADSD prior to and 1 month following Botox injection, as well as from 10 age- and gender-matched healthy adults. This yielded 3 speaking conditions: pre-Botox injection, post-Botox injection, and normal control. Thirty phrases were extracted from the speech samples and arranged in a counterbalanced listening experiment. Thirty students, reporting little experience with distorted speech, served as listeners. Each listener's response was scored for words correctly identified using a liberal scoring criterion yielding a percentage of words correctly identified for each speaker. The results indicated that the speakers with ADSD were significantly more intelligible in the post-Botox condition than in the pre-Botox condition. The results also indicated that healthy speakers were significantly more intelligible than the speakers in both the pre- and post-Botox conditions. In general, these results indicated that intelligibility is affected in severe ADSD and that the use of Botox injection in ADSD improves intelligibility scores. However, the results also indicated that the use of Botox injection does not result in speech intelligibility similar to that of normal, non-ADSD speakers.

Botulinum toxin injections for the treatment of spasmodic dysphonia

BACKGROUND

The use of botulinum toxin for the treatment of spasmodic dysphonia is currently the treatment of choice for management of this neurological voice disorder. Over the past 20 years, botulinum toxin has been used to treat both adductor and abductor forms of the disorder, with vocal improvement noted after treatment for both. A large number of studies have attempted to document the efficacy of botulinum toxin for improvement of vocal symptoms in individuals with spasmodic dysphonia.

OBJECTIVES

To determine the effectiveness of botulinum toxin for treating spasmodic dysphonia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to July 2003), EMBASE (1974 to July 2003 ), CINAHL (through July 2003), Dissertation Abstracts International (1975 to July 2003) and PsycINFO (1975 to July 2003). The search engine FirstSearch was also used (July 2003). Reference lists for all the obtained studies and other review articles were examined for additional studies.

SELECTION CRITERIA

All studies in which the participants were randomly allocated prior to intervention and in which botulinum toxin was compared to either an alternative treatment, placebo or non-treated control group were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated all potential studies meeting the selection criteria noted above for inclusion. One study met the inclusion criteria and was included in the final analysis.

MAIN RESULTS

Only one study in the literature met the inclusion criteria. This was the only study identified which reported a treatment/no treatment comparison. It reported significant beneficial effects for fundamental frequency (Fo), Fo Range, spectrographic analysis, independent ratings of voice severity and patient ratings of voice improvement.

REVIEWERS' CONCLUSIONS

The evidence from randomized controlled trials does not allow firm conclusions to be drawn about the effectiveness of botulinum toxin for all types of spasmodic dysphonia, or for patients with different behavioral or clinical characteristics.

Acoustic variations in reading produced by speakers with spasmodic dysphonia pre-botox injection and within early stages of post-botox injection

Acoustic analysis of a reading passage was used to identify the abnormal phonatory events associated with adductor spasmodic dysphonia (ADSD) pre- and postinjection of Botulinum Toxin A (Botox). Thirty-one patients (age 22 to 74 years) diagnosed with ADSD were included for study. All patients were new recipients of Botox, and the examination of their voice occurred before and after their initial injection of Botox. Acoustic events were identified from reading samples of the Rainbow Passage produced by each of the patients. These events were examined from sentences containing primarily voiced sound segments. Dependent variables included the number of phonatory breaks, frequency shifts, and aperiodic segments--all variables previously defined by the investigators. Additionally, calculated variables were made of the percentage of time these events occurred relative to the duration of the cumulative voiced segments. A sex- and age-matched control group (+/-2 years) was included for statistical comparison. Results indicated that those with ADSD produced more aberrant acoustic events than the controls. Aperiodicity was the predominant acoustic event produced during the reading, followed by frequency shifts and phonatory breaks. Within the ADSD group, the number of atypical acoustic events decreased following Botox injection. It is important that the occurrence of specific abnormal acoustic events was sufficient to differentiate the disordered speakers from the controls following as well as preceding initial Botox injection, as indicated by discriminant function analysis. This paper complements our previous work using this acoustic analysis method for defining the abnormal events present in the voice of those with ADSD and further suggests that these measures can be used in conjunction with perceptual impressions to differentiate speakers on the basis of initial severity.

Botox treatment in adductor spasmodic dysphonia: a meta-analysis

Over the years many studies have been conducted to document the treatment effects of Botulinum toxin type A in adductor spasmodic dysphonia. The results of these studies have led to the view that overall Botulinum toxin treatment is moderately effective. This study reviews efficacy research qualitatively and quantitatively to determine the extent to which this conclusion is fully supported by the data. Although the data indicate moderate overall improvement as a result of Botulinum toxin treatment, they also suggest significant variation across patients, measurements, and treatment conditions. This result, together with methodological limitations and lack of standardization in BT efficacy research, justifies caution when making inferences regarding BT treatment benefit in adductor spasmodic dysphonia.

Assessment of posterior cricoarytenoid botulinum toxin injections in patients with abductor spasmodic dysphonia

In this study, we compared 2 techniques for injection of botulinum toxin type A (Botox) into the posterior cricoarytenoid (PCA) muscle for the treatment of abductor spasmodic dysphonia (ABSD). Fifteen patients with ABSD were enrolled in a prospective randomized crossover treatment trial comparing the 2 injection techniques. The PCA muscle was injected with 5 units on each side, with the injections staged 2 weeks apart, via either a percutaneous posterior-lateral approach or a transnasal fiberoptic approach. Eleven patients reported some benefit with the injections; however, the patient-perceived benefits were not related to changes in symptoms on blinded counts by speech pathologists. No significant reductions in the numbers of breathy breaks occurred with either technique, and no differences were found between techniques. Although patients perceived a benefit, blinded symptom counts did not substantiate these benefits. Thus, PCA muscle injections of Botox provided limited benefits to patients with ABSD, demonstrating the need for a more effective therapy for these patients.

Botulinum toxin: basic science and clinical uses in otolaryngology

The role of botulinum toxin as a therapeutic agent is expanding rapidly in otolaryngology. Botulinum toxin is a protease that blocks the release of acetylcholine from nerve terminals. Its effects are transient and nondestructive, and largely limited to the area in which it is administered. These effects are also graded according to dose, allowing for individualized treatment of patients and disorders. Botulinum toxin has been used primarily to treat disorders of excessive or inappropriate muscle contraction. In the field of otolaryngology, these include spasmodic dysphonia, oromandibular dystonia, and blepharospasm; vocal tics and stuttering; cricopharyngeal achalasia; various tremors and tics; hemifacial spasm; temporomandibular joint disorders; and a number of cosmetic applications. Botulinum toxin treatment has recently begun to show some benefit in the control of pain from migraine and tension headache. It may also prove useful in the control of autonomic dysfunction, as in Frey syndrome, sialorrhea, and rhinorrhea. In over 20 years of use in humans, botulinum toxin has accumulated a considerable safety record, and in many cases represents relief for thousands of patients unaided by other therapy.

The effect of patient factors on response outcomes to Botox treatment of spasmodic dysphonia

Injection of botulinum toxin (Botox) into the laryngeal muscles has become the treatment of choice for controlling the symptoms of spasmodic dysphonia (SD). Currently, no specific battery of objective tests to assess the outcome is universally accepted. The purpose of this study was to investigate demographic, clinical, and treatment factors with voice outcome following Botox injection. Sixty-eight patients with adductor SD who underwent at least one Botox injection during a 5-year period were studied. Voice outcome measures were made from patient self-reporting scales and included overall vocal quality, length of response, and duration of breathiness. Vocal quality was significantly correlated with the underlying severity of vocal symptoms prior to treatment, incidence of breathiness and unilateral versus bilateral injection. The length of response was greater in males and following bilateral injections. An increased period of breathiness significantly correlated with bilateral injections.

Botulinum toxin management of spasmodic dysphonia (laryngeal dystonia): a 12-year experience in more than 900 patients

OBJECTIVES

This paper reviews a 12-year experience in more than 900 patients with spasmodic dysphonia who have been treated with botulinum toxin.

STUDY DESIGN

This is a retrospective analysis of patients with adductor spasmodic dysphonia (strain-strangled voice), abductor spasmodic dysphonia (whispering voice), and adductor breathing dystonia (paradoxical vocal fold motion), all of whom have been treated with botulinum toxin injections for relief of symptom.

METHODS

All of the patients were studied with a complete head and neck and neurologic examination; fiberoptic laryngostroboscopy; acoustic and aerodynamic measures; and a speech evaluation including the Universal spasmodic dysphonia rating scale. Some were given electromyography. All patients received botulinum toxin injections into the affected muscles under electromyographic guidance.

RESULTS

The adductor patients had an average benefit of 90% of normal function lasting an average of 15.1 weeks. The abductor patients had an average benefit of 66.7% of normal function lasting an average of 10.5 weeks. Adverse effects included mild breathiness and coughing on fluids in the adductor patients, and mild stridor in a few of the abductor patients.

CONCLUSION

Botulinum toxin A injection of the laryngeal hyperfunctional muscles has been found over the past 12 years to be the treatment of choice to control the dystonic symptoms in most patients with spasmodic dysphonia.