Diffusion of aniline blue injected into the thyroarytenoid muscle as a proxy for botulinum toxin injection: an experimental study in cadaver larynges

A novel whole "Joint-in-Motion" device reveals a permissive effect of high glucose levels and mechanical stress on joint destruction

OBJECTIVE

Osteoarthritis (OA) has recently been suggested to be associated with diabetes. However, this association often disappears when accounting for body mass index (BMI), suggesting that mechanical stress may be a confounding factor. We investigated the combined influence of glucose level and loading stress on OA progression using a novel whole joint-in-motion (JM) culture system.

DESIGN

Whole mouse knee joints were placed in an enclosed chamber with culture media and actuated to recapitulate leg movement, with a dynamic stress regimen of 0.5 Hz, 8 h/day for 7 days. These joints were treated with varying levels of glucose and controlled for osmolarity and diffusion. Joint movement and joint space were examined by X-ray fluoroscopy and microCT. Cartilage matrix levels were quantified by blinded Mankin scoring and immunohistochemistry.

RESULTS

Culturing in the JM device facilitated proper leg extension and flexion movements, and adequate mass transport for analyzing the effect of glucose on cartilage. Treatment with higher levels of glucose either via media supplementation or intra-articular injection caused a significant decrease in levels of glycosaminoglycan (GAG) and an increase in aggrecan neoepitope in articular cartilage, but only under dynamic stress. Additionally, collagen II level was slightly reduced by high glucose levels.

CONCLUSIONS

High levels of glucose and dynamic stress have permissive effects on articular cartilage GAG loss and aggrecan degradation, implicating that mechanical stress confounds the association of diabetes with OA. The JM device supports novel investigation of mechanical stress on the integrity of an intact living mouse joint to provide insights into OA pathogenesis.

Voice Tremor and Botulinum Neurotoxin Therapy: A Contemporary Review

Voice tremor is a common, yet debilitating symptom for patients suffering from a number of tremor-associated disorders. The key to targeting effective treatments for voice tremor requires a fundamental understanding of the pathophysiology that underpins the tremor mechanism and accurate identification of the disease in affected patients. An updated review of the literature detailing the current understanding of voice tremor (with or without essential tremor), its accurate diagnosis and targeted treatment options was conducted, with a specific focus on the role of botulinum neurotoxin. Judicious patient selection, following detailed characterisation of voice tremor qualities, is essential to optimising treatment outcomes for botulinum neurotoxin therapy, as well as other targeted therapies. Further focused investigation is required to characterise the response to targeted treatment in voice tremor patients and to guide the development of innovative treatment options.

Isolated Paresis of Laryngeal Adduction: What Are the Laryngoscopic and Stroboscopic Findings?

OBJECTIVES/HYPOTHESIS

This study aimed to describe the videolaryngostroboscopic (VLS) findings in a cohort of patients with isolated paresis of laryngeal adduction and identify predictive variables that may be related to voice recovery.

STUDY DESIGN

Chart review and VLS analysis of dysphonic patients diagnosed with isolated paresis of laryngeal adduction by laryngeal electromyography (LEMG).

METHODS

Demographic, clinical, VLS, and LEMG findings were analyzed according to the outcome of dysphonia.

RESULTS

There were 17 patients, 12 males (70.6%), mean age of 46.6 years, with median dysphonia duration of 4 months (range, 1-60 months) included in the study. In all patients, gross movement of both vocal folds were normal. Laryngoscopy showed limited adduction of the ipsilateral ventricular fold, contralateral interarytenoid region deviation, and vocal fold atrophy in 100%, 94.1%, and 76.5% of patients, respectively. VLS findings included: impairment of glottic closure (94.1%), phase asymmetry (94.1%), and reduced mucosal wave on the affected side (76.5%). Predictors of good voice outcome were sudden onset (P = .012), duration of dysphonia on presentation shorter than 5 months (P = .005), and absence of polyphasic potentials on LEMG (P = .041).

CONCLUSIONS

Findings on VLS as described suggest isolated paresis of laryngeal adduction and should warrant indication of LEMG for definite diagnosis. Voice improvement may be related to clinical and LEMG findings.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:919-925, 2019.

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.