Laryngeal and Vocal Changes During Vagus Nerve Stimulation in Epileptic Patients

Left vagus nerve stimulation (VNS) by means of an implanted electrode has proven to reduce seizure frequency in epileptic patients with medically refractory seizures. This technique is now widely applied over the world. Voice changes appear to be one of the major side effects. The morphodynamic changes in the larynx and the acoustic impacts have been analyzed in detail in 7 implanted patients. Basic vagus stimulation is well tolerated. Extra stimulation induces an adductory spasm of either the ipsilateral vocal fold or the vestibular fold. The result, when the patient phonates, consists of a slight increase of F0 as well as a moderate increase of random period perturbation, but there is no evidence for the occurrence of "bifurcations." Further, as the glottic closure remains sufficient, there is no increase in turbulent noise. The lack of increase in turbulent noise and the lack of "bifurcations" appears to clearly differentiate a spasmodic contraction of the vocal cord from a unilateral vocal fold paralysis.     

Bilateral Vocal Fold Posterior Glottic/Subglottic Stenotic Web Resected with Contact Tip Nd-YAG Laser

The standard treatment for respiratory failure remains endotracheal intubation, with periods of 22 or more days being commonplace. Posterior glottic stenotic web formation, from scarring in the posterior interarytenoid area, may occur after endotracheal intubation, thermal, corrosive, or direct surgical injury. A commonly used classification system for posterior glottic stenosis divides the occurrence into four types. Type I involves an interarytenoid scar band between the vocal folds that is anterior and separate from the posterior interarytenoid mucosa. Type II stenosis involves scarring of the mucosa or musculature of the posterior interarytenoid area. Types III and IV involve unilateral and bilateral cricoarytenoid joint fixation, respectively. Strobovideolaryngoscopy (SVL), rigid and flexible fiberoptic bronchoscopy, electromyography (EMG), radiologic imaging of the neck, larynx, and trachea as well as pulmonary function tests, including flow volume loops, provide important objective measurements of upper airway obstruction. A representative case of a professional voice user who suffered a Type II posterior glottic stenosis is presented. The treatment utilized a specific contact-tip neodymium-yttrium aluminum garnet (Nd-YAG) laser delivery system to achieve precise cutting, vaporization, and coagulation simultaneously, returning tactile touch technique to the airway/voice surgeon. Completely successful restoration of voice and airway have been maintained for 2 1/2 years postoperatively.     

Botulinum Toxin Type B for Treatment of Spasmodic Dysphonia: A Case Report

Although treatment with botulinum toxin type A (BTXA) has become the standard of care for most patients with laryngeal dystonia, its use is limited by the development of resistance to the toxin in some patients. Botulinum toxin type B (BTXB) has been found to be safe and effective in the treatment of cervical dystonia, but it has not been used previously to treat spasmodic dysphonia. Our experience with BTXB in a patient who developed resistance to BTXA suggests that BTXB may be safe and effective for the treatment of laryngeal dystonia, as well.     

Total synthesis and structural elucidation of azaspiracid-1. Construction of key building blocks for originally proposed structure

Syntheses of the three key building blocks (65, 98, and 100) required for the total synthesis of the proposed structure of azaspiracid-1 (1a) are described. Key steps include a TMSOTf-induced ring-closing cascade to form the ABC rings of tetracycle 65, a neodymium-catalyzed internal aminal formation for the construction of intermediate 98, and a Nozaki-Hiyama-Kishi coupling to assemble the required carbon chain of fragment 100. The synthesized fragments, obtained stereoselectively in both their enantiomeric forms, were expected to allow for the construction of all four stereoisomers proposed as possible structures of azaspiracid-1 (1a-d), thus allowing the determination of both the relative and absolute stereochemistry of the natural product.