Introdução: A movimentação das cartilagens aritenoides desempenha importante função tanto na abdução quanto na adução das pregas vocais e, consequentemente, na produção da voz normal. A assimetria destas cartilagens pode estar presente em algumas condições clínicas, como na paralisia unilateral de prega vocal ou na luxação / subluxação de articulação cricoaritenóidea. Há carência de estudos na literatura sobre o impacto que a assimetria de cartilagens aritenoides pode provocar no fechamento glótico e sobre a melhora que a aritenoidectomia parcial superomedial poder promover nesses casos de assimetria. Objetivo: O objetivo deste estudo foi analisar os efeitos que esta assimetria posicional de aritenoides pode desencadear no fechamento glótico posterior e avaliar o benefício que a aritenoidectomia parcial superomedial pode proporcionar a estes casos. Métodos: Realizou-se estudo experimental com 10 laringes humanas excisadas de cadáveres adultos, sendo 05 do sexo masculino e 05 do feminino. O fechamento glótico foi produzido com rotação das cartilagens aritenoides bilateralmente e a assimetria de aritenoides simulada com o uso de cola no interior de uma das articulações cricoaritenóideas com fixação da cartilagem aritenoide em posição anteromedial. Na aritenoidectomia parcial, removeu-se a porção superomedial da cartilagem submetida à assimetria. O fechamento glótico posterior foi avaliado com paquímetro digital para medir a distância entre os processos vocais antes e após a simulação da assimetria e da aritenoidectomia superomedial, para que as medidas fossem comparadas. Resultados: O fechamento glótico posterior de todas laringes estudadas passou de completo para incompleto após a simulação da assimetria posicional de aritenoides, sendo a distância média observada entre os processos vocais de 1,766mm (IC95%: 1,519-2,013). A aritenoidectomia superomedial realizada após a assimetria de aritenoides fez com que o fechamento glótico posterior voltasse de incompleto para completo em todas laringes da pesquisa. Conclusões: Os resultados da pesquisa sugerem que a assimetria posicional de cartilagens aritenoides parece comprometer o fechamento glótico posterior, aumentando a distância entre os processos vocais durante a adução das pregas vocais. Além disso, o estudo aponta que a aritenoidectomia superomedial pode melhorar o fechamento glótico posterior nestes casos de assimetria de aritenoides / Introduction: The movement of arytenoid cartilage plays an important role both in abduction and adduction of the vocal folds and, consequently, in the production of normal voice. The asymmetry of these cartilages may be present in some clinical conditions, such as in unilateral vocal fold paralysis or in the cricoarytenoid joint dislocation / subluxation. There is a lack of studies in the literature on the impact that the positional asymmetry of arytenoid cartilages can cause in the glottic closure and on the improvement that the superomedial partial arytenoidectomy can promote in these cases of asymmetry. Objective: The objective of this study was to analyze the effects that this arytenoid positional asymmetry can trigger in posterior glottic closure and to evaluate the benefit that superomedial partial arytenoidectomy can provide to these cases. Methods: An experimental study was carried out on 10 human larynx excised from adult cadavers, being 05 males and 05 females. Glottic closure was produced with rotation of the arytenoid cartilages bilaterally and the simulated arytenoid asymmetry with the use of glue inside one of the cricoarytenoid joints with anteromedial fixation of the arytenoid cartilage. In partial arytenoidectomy, the superomedial portion of the cartilage submitted to the asymmetry was removed. Posterior glottic closure was evaluated with a digital caliper to measure the distance between vocal processes before and after the simulation of asymmetry and superomedial arytenoidectomy, so that the measurements were compared. Results: The posterior glottic closure of all studied larynges went from complete to incomplete after the simulation of arytenoid positional asymmetry, with the mean distance observed between vocal processes of 1,766mm (95% CI: 1,519-2,013). Superomedial arytenoidectomy performed after arytenoid asymmetry caused the posterior glottic closure to return from incomplete to complete in all larynges of the study. Conclusions: The results of the research suggest that the positional asymmetry of arytenoid cartilages seems to compromise posterior glottic closure, increasing the distance between the vocal processes during vocal fold adduction. In addition, the study points out that superomedial partial arytenoidectomy may improve posterior glottic closure in these cases of arytenoid asymmetry

Much of the impetus for this research can be attributed to Kenneth W. Hinchcliff, who has studied exercise-induced pulmonary haemorrhage (EIPH) extensively. This thesis focused on EIPH in Thoroughbred racehorses competing in South Africa. Using tracheobronchoscopy, the prevalence and severity of EIPH and the association with racing performance was determined. Thereafter, the prevalence of other respiratory tract disorders and their association with racing performance is reported. This is followed by a study assessing interobserver variability using grading systems in the detection of respiratory tract disorders. Finally, there is a report on the immunopathogenesis of EIPH. Using tracheobronchoscopy after racing, the prevalence and severity of EIPH was assessed in 1,005 racehorses competing at high altitude (> 1,400 meters above sea level) and at sea level in a racing jurisdiction that does not allow the use of furosemide and nasal dilator strips. The prevalence and severity of EIPH was affected by altitude as racing at sea level was associated with a higher prevalence and greater severity of EIPH. Results also suggested that EIPH was associated with superior performance in South African Thoroughbred racehorses. Upper and lower respiratory tract disorders identified following tracheobronchoscopic examination included left arytenoid asymmetry, left laryngeal hemiplegia, epiglottic deformity, epiglottic entrapment, subepiglottic cysts, dorsal displacement of the soft palate, pharyngeal lymphoid hyperplasia (PLH), laryngeal and tracheal dirt, tracheal mucous (TM), tracheal stenosis and tracheal cartilage ring spikes in Thoroughbred racehorses after racing. Overall, there was a low prevalence of grade 2 and 3 arytenoid cartilage asymmetry, left laryngeal hemiplegia, epiglottic entrapment, subepiglottic cysts and epiglottic deformity, while more severe grades of PLH, laryngeal debris, tracheal debris, TM and tracheal cartilage ring spikes had a higher prevalence. An association with sex was identified as tracheal cartilage ring spikes occurred more often in male racehorses. Superior racing performance was identified in racehorses with grade 3 tracheal mucous and tracheal cartilage ring spikes. Endoscopic grading of EIPH, PLH, arytenoid cartilage movement (ACM), and TM was performed by 3 observers that were blinded to each racehorse’s identity and race day performance using previously established grading criteria. Excellent interobserver reliability was seen using the EIPH grading system, while the weighted kappa for PLH, ACM and TM was lower. The study demonstrated sufficient reliability for the use of the EIPH, PLH, ACM and TM grading systems in racehorses competing in South Africa. The study concluded that tracheobronchoscopy seemed to be a practical screening technique that may have prognosticative validity and clinical dependability and that would allow safe and quick assessment of the respiratory tract of a large number of racehorses in field conditions. Venous blood was collected from 10 horses in each EIPH grade classification (grade 0 to 4) following tracheobronchoscopic examinations for the determination of the presence and severity of EIPH. Following RNA isolation and cDNA synthesis, real-time PCR was used to detect equine cytokine-specific mRNA for interleukin (IL) -1, -6, -10, interferon (INF) -ã, and tumor necrosis factor (TNF) -á. Results of this study indicated that increased IL-6, and -10 mRNA production was associated with more severe forms of EIPH. Also, there was greater expression of IL-6 mRNA at sea level and TNF-á mRNA at high altitude. This study concluded that although it was unclear whether the inflammatory response observed in the study was due to pre-existing pulmonary inflammation or as a direct consequence of pulmonary bleeding, the study demonstrated a systemic correlation to pulmonary inflammation. The research reported in this thesis has contributed substantially to the determination of the prevalence, severity and affect on racing performance of respiratory tract disorders in Thoroughbred racehorses competing in South Africa. Also, determination of an association between EIPH and inflammation at a molecular level may assist future researchers in anti-cytokine therapies which may help reduce the prevalence and severity of EIPH. / Thesis (PHD)--University of Pretoria, 2007. / Companion Animal Clinical Studies / unrestricted