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Background: Intubation trauma is the most common cause of arytenoid dislocation. The aim of this study was to investigate the diagnosis and treatment of arytenoid cartilage dislocation from external blunt laryngeal trauma in the absence of laryngeal electromyography (LEMG) and to explore the role of early attempted closed reduction in arytenoids cartilage reposition., Material and Methods: This 15-year retrospective study recruited 12 patients with suspected arytenoid dislocation from external blunt laryngeal trauma, who were evaluated through 7 approaches: detailed personal history, voice handicap index (VHI) test, indirect laryngoscope, flexible fiberoptic laryngoscope, video strobolaryngoscope, and/or high-resolution computed tomography (CT), and, most importantly, the outcomes after attempted closed reduction under local anesthesia. They were divided into satisfied group (n=9) and dissatisfied group (n=3) based on their satisfied with voice qualities at 1 week after the last closed reduction manipulation., Results: Each patient was diagnosed with arytenoid dislocation caused by external blunt laryngeal trauma. In the satisfied group, VHI scores and maximum phonation time (MPT) at 1 week after the last reduction were significantly improved compared with those before the procedure (P<0.05). Normal or improved mobility and length of the affected vocal fold were also noted immediately after the end of the last closed reduction. The median time interval between injury and clinical intervention in satisfied group was 43.44±34.13 days, much shorter than the median time of 157.67±76.07 days in the dissatisfied group (P<0.05)., Conclusions: Multimodality assessment protocols are essential for suspected arytenoid dislocation after external blunt laryngeal trauma. Early attempted closed reduction should be widely recommended, especially in health facilities without LEMG, mainly, because it could be helpful for early diagnosis and treatment of this disease. In addition, early closed reduction could also improve the success of arytenoid reduction.

Objectives/hypothesis: Evaluate the effect of injection laryngoplasty (IL), medialization laryngoplasty (ML), and ML combined with arytenoid adduction (ML-AA) on acoustic, aerodynamic, and mucosal wave measurements in an excised larynx setup., Study Design: Comparative case study using ex vivo canine larynges., Methods: Measurements were recorded for eight excised canine larynges with simulated unilateral vocal fold paralysis before and after vocal fold injection with Cymetra. A second set of eight larynges was used to evaluate medialization laryngoplasty using a Silastic implant without and with arytenoid adduction., Results: IL and ML led to comparable decreases in phonation threshold flow (PTF), phonation threshold pressure (PTP), and phonation threshold power (PTW). ML-AA led to significant decreases in PTF (P = .008), PTP (P = .008), and PTW (P = .008). IL and ML led to approximately equal decreases in percent jitter and percent shimmer. ML-AA caused the greatest increase in signal-to-noise ratio. ML-AA discernibly decreased frequency (P = 0.059); a clear trend was not observed for IL or ML. IL significantly reduced mucosal wave amplitude (P = 0.002), whereas both ML and ML-AA increased it. All procedures significantly decreased glottal gap, with the most dramatic effects observed after ML-AA (P = 0.004)., Conclusions: ML-AA led to the greatest improvements in phonatory parameters. IL was comparable to ML aerodynamically and acoustically, but caused detrimental changes to the mucosal wave. Incremental improvements in parameters recorded from the same larynx were observed after ML and ML-AA. To ensure optimal acoustic outcome, the arytenoid must be correctly rotated. This study provides objective support for the combined ML-AA procedure in tolerant patients.

To investigate the prevalence of asymmetries at vocal fold adduction, 109 vocally healthy subjects between 22 and 80 years of age were examined. All subjects were examined with a rigid endoscope and video recorded. The recordings were analysed off line by two laryngologists. Seventy percent of the subjects displayed some kind of asymmetry. There was no difference between the sexes. Side differences in antero-posterior position of the corniculate or cuneiform tubercles were the most frequent asymmetries, occurring in 66% of the total material and in 92% of the asymmetrical cases. Asymmetries appeared more common and more marked in older subjects and possibly more frequent in singers than in non-singers. Laryngeal adduction asymmetries are probably of little importance for voice function.

We tested the hypotheses that active upper airway closure during induced central apneas in nonsedated lambs 1). is complete and occurs at the laryngeal level and 2). is not due to stimulation of the superior laryngeal nerves (SLN). Five newborn lambs were surgically instrumented to record thyroarytenoid (TA) muscle (glottal constrictor) electromyographic (EMG) activity with supra- and subglottal pressures. Hypocapnic and nonhypocapnic central apneas were induced before and after SLN sectioning in the five lambs. A total of 174 apneas were induced, 116 before and 58 after sectioning of the internal branch of the SLN (iSLN). Continuous TA EMG activity was observed in 88% of apneas before iSLN section and in 87% of apneas after iSLN section. A transglottal pressure different from zero was observed in all apneas with TA EMG activity, with a mean subglottal pressure of 4.3 +/- 0.8 cmH2O before and 4.7 +/- 0.7 cmH2O after iSLN section. Supraglottal pressure was consistently atmospheric. Sectioning of both iSLNs had no effects on the results. We conclude that upper airway closure during induced central apneas in lambs is active, complete, and occurs at the glottal level only. Consequently, a positive subglottal pressure is maintained throughout the apnea. Finally, this complete active glottal closure is independent from laryngeal afferent innervation.

Reasons for Performing Study: Laryngoplasty (LP) is currently the most common surgical treatment for equine laryngeal paralysis, however, there have been no reports quantifying the degree of retention of arytenoid abduction following LP. Additionally, the complications of LP have been poorly documented., Objectives: To record the degree of arytenoid abduction retention following LP and to accurately document all complications of surgery., Methods: A study (1986-1998) of 200 horses of mixed breed and workload, median age 6 years (prospective 136 cases and retrospective 64 cases) undergoing LP (using 2 stainless steel wires) and combined ventriculocordectomy was undertaken; 198 owners completed questionnaires, a median of 19 months following surgery. The degree of arytenoid abduction achieved was endoscopically, semi-quantitatively evaluated using a 5-grade system, at 1 day, 7 days, and 6 weeks after surgery., Results: On the day following LP, 62% of horses had good (median grade 2) arytenoid abduction, 10% had excessive (grade 1), and 5% had minimal (grade 4) abduction (overall-median grade 2). Due to progressive loss of abduction, moderate (median grade 3, range 1-5) abduction was present overall at 1 and 6 weeks after LP. Further surgery was required to re-tighten prostheses in 10% of cases with excessive loss of abduction, or to loosen prostheses in 7% of horses which had continuing high levels of LP abduction and significant post operative dysphagia. LP wound problems (mainly seromas and suture abscesses) were reported to last < 2 weeks in 9% of cases, < 4 weeks in 4% and > 4 weeks in 4%. The (partially sutured) laryngotomy wounds discharged post operatively for < 2 weeks in 22% of cases, < 4 weeks in 7% and for > 4 weeks in 2%. Coughing occurred at some stage post operatively in 43% of cases and its presence correlated significantly with the degree of surgical arytenoid abduction. This coughing occurred during eating in 24% of cases and was not associated with eating (or dysphagia) in the other 19% of cases. Chronic (> 6 months duration) coughing occurred in 14% of cases, but appeared to be due to intercurrent pulmonary disease in half of these horses., Conclusions: Suturing the cricotracheal membrane allows most laryngotomy wounds to heal quickly. Laryngoplasty wound problems were of little long-term consequence when stainless steel wire prostheses were used., Potential Relevance: A significant loss of LP abduction occurs in most horses in the 6 weeks following surgery and efforts should be made to find ways to prevent such loss. However, excessive LP abduction is associated with post operative dysphagia and coughing.

A prosthesis, composed of a steel cable and stress-reducing washers, was developed to prevent failure of laryngoplasty, a common treatment for horses affected by recurrent laryngeal neuropathy. Laryngoplasties were performed on 15 cadaveric larynges using a polyester suture on one side and the cable prosthesis on the other. Each prosthesis was distracted at a displacement rate of 20 mm/s using a servohydraulic materials testing machine until laryngoplasty failed. Distraction force and actuator displacement were recorded and analysed. All 15 laryngoplasties performed with a suture failed at the muscular process at a mean +/- s.d. force of 55.8 +/- 13.1 N. Six laryngoplasties performed with the cable prosthesis failed at the muscular process at mean force 219.6 +/- 125.0 N. In the other 9, the arytenoid cartilage was avulsed from the larynx at mean force 206.4 +/- 75.3 N, and the cable then tore through the muscular process at mean force 357.0 +/- 32.0 N. The difference in force required to cause failure of laryngoplasty was significant (P<0.0001). Although the prosthesis resisted substantially higher forces than did the suture, the effects of the prosthesis in vivo must be evaluated.

In almost every type of functional laryngeal operation a successful result hinges on the surgeon's ability to control the muscular and ligamentous forces that act upon the vocal folds. Most of the time these forces are small in relation to the manipulations and resections performed. Occasionally, the forces are significant relative to the problem encountered, resulting in a failed surgery. Of all the many conditions that fit in to this latter description, perhaps the best example in arytenoid dislocation. Dislocation of the arytenoid is usually secondary to trauma with the majority of reported cases resulting from some type of anesthetic misadventure. Two types of dislocation have been described, anteromedial and posterolateral, each with a different mechanism of causation. This paper concerns itself with the more common anteromedial variety and its treatment using botulinum toxin.

Medialization laryngoplasty has become a routine procedure for cases of unilateral vocal fold paralysis. In certain clinical situations, it may become desirable to reverse the procedure and remove the implant. This process was studied experimentally in eight dogs in a chronic model of induced canine phonation. A silicone polymer implant was inserted to medialize one normal vocal fold for a period of 1 month, after which it was removed. Motion of the cricoarytenoid (CA) joint and induced phonation were studied weekly while the implant was in place, and for another month following implant removal. Significant abnormalities were found even with this relatively short period of implantation. With the implant in place, impairment of CA joint mobility was found in seven of the eight dogs, precluding phonation. A dense fibrous capsule rapidly developed around the implant, making its removal technically difficult. Following implant removal, a gradual return to normal function was found in only three of the eight dogs. One of the animals had evidence of neural injury, while four had intact neural function but impaired mobility or fixation of the CA joint. Medialization laryngoplasty should not be considered a reversible procedure. The clinical implications of these findings are discussed.

This study was designed to define a simple, unequivocal test for the evaluation of laryngeal function and the diagnosis of idiopathic laryngeal hemiplegia (ILH). ILH is a disorder that results from left recurrent laryngeal neuropathy and in which there is no movement of the left arytenoid cartilage and vocal fold. Laryngeal function was evaluated in seven horses using four techniques designed to stimulate laryngeal movements:-nasal occlusion, exercise, swallowing and administration of a respiratory stimulant. In addition, the effects of sedation and twitching on the endoscopic examination were also examined. The cross-sectional area of the rima glottidis was measured in each horse at rest and after each technique was performed. There was no statistically significant difference in the increase in area seen after nasal occlusion or exercise. Doxapram hydrochloride increased the cross-sectional area of the rima glottidis, whereas xylazine caused a decrease. Neither of these pharmacological agents exaggerated or decreased the amount of asynchronous movement or tremoring of the arytenoid cartilages. Manual occlusion of the external nares during endoscopy is a simple, yet effective method of stimulating arytenoid function and hence diagnosing ILH.

Using fluoroscopic techniques and videotape recordings, a study of normal deglutition was made in 2 ponies. Paryngeal function was studied at intervals after laryngoplasty on 1 animal and after a sham technique on the other. Two clinical cases of laryngeal paralysis, which had been treated by laryngoplasty, were also examined. In the 2 experimental ponies, liquid food passed into the lower respiratory tract post-operatively. One of the clinical cases appeared to swallow solid food normally, but some food material entered the larynx of the other horse. It is suggested that pharyngeal dysfunction, as well as over-abduction of the arytenoid cartilage, might be involved in causing the chronic post-operative cough which the experiment was designed to investigate.