Laryngoplasty Research Articles

The effect of repeated freezing and thawing on the suture pull-out strength in equine arytenoid and cricoid cartilages.

To assess the effect of repeated freezing and thawing on the suture pull-out strength in arytenoid and cricoid cartilages subjected to the laryngoplasty (LP) procedure. Ex vivo experimental study. Ten grossly normal equine cadaveric larynges. Bilateral LP constructs were created using a standard LP technique. One hemilarynx was randomly allocated to the single freeze and thaw group and the other allocated to the repeated freeze and thaw (3 complete cycles) group. The suture ends of each LP construct were attached to a load frame and subjected to monotonic loading until construct failure. Mean load (N) and displacement (mm) at LP construct failure were compared between groups. All LP constructs failed by suture pull through the arytenoid cartilage. The mean load at failure was similar between groups (118.9 ± 25.5N in the single freeze and thaw group and 113.4 ± 20.5N in the repeated freeze and thaw group, P=.62). The mean displacement at failure was similar between groups (54.4 ± 15.1 mm in the single freeze and thaw group and 54.4 ± 15.4 mm in the repeated freeze and thaw group, P=.99). Repeated freezing and thawing did not affect the suture pullout strength of the arytenoid and cricoid cartilages. Laryngeal specimens that have been subjected to repeated freezing and thawing can be utilized in the experimental evaluation of LP procedures because there is no alteration of the suture pull-out strength of the relevant cartilages.

Outcomes of horses treated with removal of a laryngoplasty prosthesis

To determine the proportion of horses treated by laryngoplasty prosthesis removal (LPR) for complications associated with prosthetic laryngoplasty (LP), the reason for LPR, and the outcome of horses undergoing LPR to manage iatrogenic coughing/dysphagia. Retrospective study. Client-owned horses treated with LP (n = 1202) and LPR (n = 58). Clinical case records were reviewed to determine the number of horses treated with LP and LPR by the same surgeon. Historical, clinical, endoscopic, and surgical data were extracted for those horses undergoing LPR. Long-term outcome was assessed by questionnaire. The proportion of horses treated with LP and subsequently treated with LPR by the same surgeon was 3.5% (42/1202). Coughing/dysphagia was the reason for LPR in 90% (52/58) of horses. Sufficient follow-up to determine outcome in horses undergoing LPR for coughing/dysphagia was available in 32 horses. Arytenoid abduction grade at the time of LPR did not influence clinical response (P = .416). Presenting clinical signs resolved after LPR in 21 of 32 (66%) horses, and 24 of 32 (75%) horses returned to exercise. Coughing/dysphagia was the most common reason for LPR. Clinical signs improved in most horses after LPR. Laryngoplasty prosthesis removal can be a useful treatment option for horses affected with unmanageable coughing/dysphagia caused by LP.

Aryepiglottic fold augmentation as treatment for late-onset dysphagia following surgical treatment of recurrent laryngeal neuropathy.

Coughing and dysphagia have been described following prosthetic laryngoplasty (LP) with or without ventriculectomy/ventriculocordectomy (VE/VCE) for the treatment of recurrent laryngeal neuropathy. All previous case descriptions include patients with acute onset of clinical signs after surgery that persisted. The authors observed a late-onset of dysphagia and coughing months to years after LP±VE/VCE. The condition was always associated with an abnormality of the aryepiglottic fold (AEF). Treatment options for those patients are limited. We suggest augmentation of the AEF as treatment for affected horses. The goal of the study was two-fold: Firstly, to describe a new condition of late-onset dysphagia in horses following LP±VE/VCE associated with an abnormal appearance of the AEF, and secondly, to offer a minimally invasive and successful treatment for those patients. Six horses were presented because of dysphagia and coughing with an onset of months to years after LP±VE/VCE. Endoscopically, the AEF always appeared thinner and more flaccid to a varying degree. The food path was traceable along the AEF into the trachea using dyed molasses. An initial injection of hyaluronic acid (HA) into the AEF led to immediate improvement of the dysphagia. The procedure was performed in the standing sedated horse. The needle was placed through the cricothyroid ligament and the injection performed under endoscopic guidance. All horses tolerated the injection well. Injection of HA was successful only in the short term in all cases and repeated injections were needed for permanent resolution using either cross-linked HA, polyacrylamide hydrogel or platelet rich plasma. Horses may develop dysphagia and coughing months to years after LP±VE/VCE as a late-onset complication. The condition seems to be associated with an abnormal appearance and function of the AEF. Successful treatment is possible by augmenting the AEF. However, careful patient selection is mandatory.

Dynamic respiratory endoscopic findings pre- and post laryngoplasty in Thoroughbred racehorses.

To investigate laryngeal function in cases of recurrent laryngeal neuropathy pre- and post laryngoplasty (LP) using dynamic respiratory endoscopy (DRE). To compare the rima glottidis area during DRE pre- and post LP; document all forms of dynamic upper airway obstruction (DUAO) pre- and post LP and investigate the relationship between post operative abduction at rest and exercise. Prospective case series. Thoroughbred racehorses with pre- and post LP DRE were included. Left-to-right arytenoid cartilage angle ratios and rima glottidis area ratios were used to quantify laryngeal function during rest and exercise, pre- and post LP. In 35 horses, mean pre-LP ratios were greater during rest (left-to-right quotient angle ratio [LRQ] 0.76 ± 0.13; left-to-right arytenoid ratio [LRR] 0.72 ± 0.14; rima glottidis area ratio [RGA] 0.40 ± 0.10) than exercise (LRQ 0.39 ± 0.16, P < 0.001; LRR 0.38 ± 0.16, P < 0.001; RGA 0.15 ± 0.05, P < 0.001). Exercising ratios were larger post LP (LRQ 0.61 ± 0.13; LRR 0.60 ± 0.12; RGA 0.30 ± 0.08) than pre-LP (LRQ 0.39 ± 0.16, P < 0.001; LRR 0.38 ± 0.16, P < 0.001; RGA 0.15 ± 0.05, P < 0.001). A positive linear relationship was found between post LP resting and exercising ratios (R(2) = 0.48; P < 0.001) and post operative abduction grades (R(2) = 0.63; P < 0.001). Pre-LP all horses demonstrated left arytenoid cartilage collapse with bilateral vocal cord collapse and 37% had aryepiglottic fold collapse. Post LP 13 horses (37%) developed additional DUAOs and these horses had smaller RGAs (0.25 ± 0.08) than horses that did not develop DUAOs (0.32 ± 0.07, P = 0.01). Multiple forms of DUAO occurred pre-LP and additional forms often developed post LP. Post LP the degree of arytenoid cartilage abduction at rest was useful to predict the degree of abduction during exercise.

Upper Esophageal Incompetence in Five Horses After Prosthetic Laryngoplasty

To describe a complication observed endoscopically in horses after prosthetic laryngoplasty (LP). Case series. Horses (n = 5) that had previous LP. Four horses had endoscopic examination as part of a larger prospective study and had saliva emanating from their upper esophageal opening. One other horse was referred with clinical signs of severe upper esophageal obstruction 2 months after LP. Four horses were observed to have saliva emanating from their upper esophageal opening during endoscopic examination 21-58 months after LP. Esophageal reflux was noted endoscopically at rest (n = 1) and during exercise (4). All 5 horses were reported to cough postoperatively, and 2 horses coughed severely when eating. On necropsy, the horse referred with signs of esophageal obstruction had dilation of the proximal esophagus associated with food impaction and had fibrosis and thickening of the left cricopharyngeus and thyropharyngeus muscles. Iatrogenic damage to the caudal pharyngeal constrictor muscles, the intrinsic musculature of the upper esophagus, or their innervation, or damage to the peri-esophageal fascia or esophageal adventitia may cause upper esophageal incompetence in horses after LP.

Characterisation of palatal dysfunction after laryngoplasty

Dorsal displacement of the soft palate (DDSP) in the horse has been previously described as intermittent, typically occurring at fast exercise; or persistent, seen at rest. Dorsal displacement of the soft palate has recently been reported following laryngoplasty (LP) and can be associated with continued poor performance and respiratory noise. The current study aimed to characterise the DDSP diagnosed post LP. Cross-sectional study. Owners/trainers of horses undergoing LP at one institution over 6 years were contacted to determine the horse's progress and willingness for re-examination. The horses were examined at the rest, walk, trot and canter with an overground exercising endoscope. A GPS-equipped watch was carried to obtain maximal exercising speeds. Videos of horses with DDSP were reviewed to determine frequency and duration of DDSP and swallowing events at the various gaits. Exercising endoscopy was performed in 41 of the 89 horses that had undergone LP. Nineteen of the 41 horses were diagnosed with DDSP at exercise, of which 7/41 also had DDSP at rest. No difference was detected in the percentage of total time spent displaced at each gait (P = 0.67), or in the frequency of new DDSP events per minute between each gait (P = 0.10), or in the frequency of swallowing events per minute between each gait (P = 0.52). The majority of horses displaced at various times throughout each gait. Dorsal displacement of the soft palate was most commonly solely induced spontaneously and always corrected with a swallow. The maximum speed achieved was 8.3 m/s. Dorsal displacement of the soft palate was common following LP and it appears to be induced at slower gaits than DDSP that has previously been described. It also occurred at various times throughout each gait and did not always occur persistently at rest. These findings suggest horses undergoing LP may be more prone to DDSP and further investigations into the aetiology of post LP palatal dysfunction are warranted.

Long‐Term Maintenance of Arytenoid Cartilage Abduction and Stability During Exercise After Laryngoplasty in 33 Horses

To (1) assess long-term maintenance of arytenoid cartilage abduction (ACA) after laryngoplasty (LP); and (2) correlate the residual grade of ACA and postoperative abductory loss with arytenoid cartilage stability (ACS) during exercise. Case series. Horses re-examined after laryngoplasty (n = 33). Of 89 LP horses (2005-2010), 33 had historic ACA data available and upper airway endoscopy at rest and during over-ground exercise (mean, 33 months; range, 4-71 months) after surgery. ACA grade at 1 and 6 weeks postoperatively were correlated to long-term ACA grade. Effects of long-term ACA grade and magnitude of postoperative abductory loss on ACS during exercise were investigated. Median ACA grade at 1 week (n = 33) was 2, reducing to grade 3 by week 6 (n = 16). Grade 3 abduction was maintained in the long-term. Correlation between ACA at 1 week and the long-term was poor (ρ = .43, P = .1), but there was good correlation between week 6 and long-term (ρ = .89, P < .001). Arytenoid cartilage instability was observed during exercise in 7/33 of horses, and not significantly associated with the ACA grade (P = .50), or the number of grades of ACA lost (P = .64). Limited abductory loss occurs after 6 weeks postoperatively. Resting ACA grade was not a useful predictor of ACS during exercise.

Long‐term exercising video‐endoscopic examination of the upper airway following laryngoplasty surgery: A prospective cross‐sectional study of 41 horses

To investigate upper respiratory tract function in horses, previously undergoing laryngoplasty (LP), using exercising video-endoscopy. To evaluate arytenoid abduction and stability, diagnose any concurrent upper airway problems, and correlate these with the owners' perception of success. Horses undergoing LP during a 6-year period at one hospital were initially included. Those available for re-examination were exercised for a duration and intensity considered maximal for their discipline using an over-ground endoscope. Resting and exercising laryngeal and pharyngeal videos were analysed blindly. Multivariable analysis was used to test associations between resting and exercising endoscopic variables, and also between endoscopic variables and owner questionnaire findings. Forty-one horses were included and 78% had a form of upper airway collapse at exercise, with 41% having complex forms, despite 93% of owners reporting the surgery to have been beneficial. Horses with poor abduction (grades 4 or 5/5) were 6 times more likely to make respiratory noise compared with those with good (grades 2 or 3/5) abduction (P = 0.020; 95% confidence interval [CI] 1.3-27.0), and those not having a ventriculectomy were 4.9 times more likely to produce respiratory noise post operatively (P = 0.048; 95% CI 1.0-23.9). Palatal dysfunction was observed in 24% of horses at rest, and 56% at exercise, with the diagnosis at rest and exercise significantly associated (P = 0.001). Increasing severity of pharyngeal lymphoid hyperplasia (prevalence 61%) was significantly associated with increasing arytenoid abduction (P = 0.01). Thirty-four per cent of horses had aryepiglottic fold collapse and 22% of horses had vocal fold collapse. Many horses that had previously had LP were diagnosed with upper airway abnormalities, despite the procedure being considered as beneficial by most owners. When investigating cases of ongoing respiratory noise or poor performance following LP, exercising endoscopy must be considered. Continued respiratory noise may be associated with poor arytenoid abduction and not performing concurrent ventriculectomy.

Race Performance After Laryngoplasty and Ventriculocordectomy in National Hunt Racehorses

To evaluate the effect of laryngoplasty (LP) on race performance in longer distance (National Hunt) Thoroughbred racehorses. Case-control study. National Hunt Thoroughbred racehorses (n=71) and race-matched controls (n=126). Race records for National Hunt racehorses that had LP and ventriculocordectomy were analyzed and racing performance was compared with race-matched controls. Sixty-three of 71 cases were matched with controls. Postoperatively, 78% of cases raced, 47% improved their individual performance and cases were as likely to start in 1 or 3 races as controls. In the 5 preoperative races, case horses earned less prize money than race-matched controls but there was no difference in prize money earned in 5 postoperative races between groups. Cases started in significantly fewer total (lifetime) races both before and after the date of surgery compared with controls. LP seemingly restored short-term postoperative racing performance of National Hunt horses to a level comparable with that of a matched control population; however, the career "longevity" of case horses appears to be shorter than that of control horses. LP appears to be a suitable treatment for recurrent laryngeal neuropathy in National Hunt racehorses.

Postoperative Race Performance is Not Correlated with Degree of Surgical Abduction After Laryngoplasty in National Hunt Thoroughbred Racehorses

To (1) assess the degree of arytenoid cartilage abduction lost after laryngoplasty (LP) in Thoroughbred National Hunt racehorses and (2) to correlate postoperative racing performance with degree of arytenoid abduction after LP. Case series. National Hunt Thoroughbred racehorses (n=68). Grade of postoperative arytenoid abduction for National Hunt racehorses that had LP with ventriculocordectomy was assessed at 1 day, 6 days, and 6 weeks after LP. Race records were analyzed to ascertain if there was correlation between the degree of arytenoid cartilage abduction and various measures of race performance (return to racing postoperatively, total earnings in 5 races immediately postoperatively, and lifetime number of starts postoperatively). Median postoperative arytenoid abduction was grade 2 on day 1 but had decreased to grade 3 by 6 weeks. Horses with grades 1, 2, and 3 abduction 1 day after surgery had median losses of 1, 1, and 0.5 abduction grades, respectively, at 6 weeks. Horses with grade 1 abduction on day 1 were significantly more likely to lose abduction by day 6 after surgery than horses with grade 3 abduction on day 1. There was no statistically significant correlation between the postoperative grade of arytenoid abduction at any time point and earnings in 5 races after surgery, likelihood of racing postoperatively, or total number of lifetime race starts postoperatively. Horses with maximal (grade 1) surgical arytenoid abduction are significantly more likely to suffer postoperative loss of abduction than those with grade 3 abduction. Postoperative grade of abduction does not appear significantly correlated with markers of racing performance in National Hunt racehorses; however, very few horses with poor (grade 4 or 5) abduction were included and thus conclusions regarding racing performance in such horses cannot be drawn from this study. Seemingly, most horses with grade 3 laryngeal abduction can race successfully and perhaps surgeons should not be disillusioned by the appearance of only moderate (grade 3) abduction in the long term after LP in racehorses.

Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 1: Maintenance of surgical arytenoid abduction and complications of surgery.

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. To record the degree of arytenoid abduction retention following LP and to accurately document all complications of surgery. 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. 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. 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. 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.

Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 2: Owners' assessment of the value of surgery.

There is continuing debate on the clinical benefit of laryngoplasty (LP) in the treatment of equine laryngeal paralysis. In particular, there is little information available on the clinical value of this surgery in older horses, in non-Thoroughbreds or in sports or pleasure horses; nor on the relationship between the degree of LP abduction achieved and the clinical value of LP. To evaluate the owner's assessment of the value of LP (and combined ventriculocordectomy) in an older, mixed breed and mixed workload population of horses and to also assess the relationship between the degree of LP abduction present and the clinical value of this surgery. 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 and ventriculocordectomy was undertaken. The degree of laryngoplasty abduction achieved and maintained was semiquantitatively evaluated using a 5-grade system. A survey of 198 owners, a median of 19 months after LP surgery, showed that 91% of cases had returned to full work and 3% to reduced work, including 95% of horses with good (Grade 2) laryngoplasty abduction at 6 weeks after surgery, 91% with moderate (Grade 3) abduction, 88% of cases with minsimal (Grade 4) abduction and just 25% of cases with total loss of surgical abduction (Grade 5). Once back in work, 73% of cases were reported to make no abnormal exercise-related noises ('noises') at exercise, with reduced 'noises' reported in some of the 21% of horses that still made 'noises'. In the other 6% of cases, owners were unsure if 'noises' were present. The absence or presence of 'noises' once back at work correlated significantly with the degree of surgical arytenoid abduction present at 6 weeks after LP. Once back in work, 'noises' were less commonly detected in sports and pleasure horses (absent in 76% of cases) than in racehorses (absent in 60%) of cases. Exercise performance following surgery was reported to be markedly increased in 75% of cases, with 10% showing no difference in exercise performance, 3% showing worse performance, and owners unsure of any effect on exercise performance in 13% of cases. Improved work was reported in 70% of sports and pleasure horses and in 67% of racehorses. Overall, 86% of owners believed LP was worthwhile, 7% believed it was not worthwhile and 6% were unsure of its value. Surgery was reported to be of most benefit to sports horses (e.g. reported worthwhile for 100% of show jumpers) and of least benefit to National Hunt (long distance) racehorses where 71% of owners believed it to be worthwhile. Most horse-owners believe that LP and combined ventriculocordectomy are of clinical value, especially in sports and pleasure horses. Large scale physiological studies on clinical cases, pre- and post operatively, are required to examine more critically the value of such surgery.

LARYNGOPALSTY

Laryngoplasty ia a surgical technique for repairing of a defect or deformity and for restoring of function of the larynx. In this paper, the author dealt with the laryngoplasty performed on the laryngectomized patients, and discussed on the problems of postoperative aspiration of food or a salivary flow into the trachea. Out of 41 patients received Asai's method, 37 patients had the aspiration problems. Aspiration is one of the embarrassing problems after laryngoplasty and may have been a cause of pneumonia which is sometime fatal, and the author suggested that for the prevention of aspiration of food the patients must learn to press on the pharyngeal fistula externally on the anterior neck during food intake.Aspiration of a flow of saliva into the trachea or the reflected swallowing of saliva through the pharyngeal fistula is another type of aspiration problems, but fortunately in the most cases an amount of salivary flow is unexcessive and it will be removed by a cough. The author investigated the tracheal mucous membrane in the patients with the pharyngeal fistula and found that aspiration of saliva into the trachea may have prevented driness of the mucous membrane of the respiratory tract.In the author's series of laryngoplasty, two patients developed pneumonia possiblly due to aspiration of food or fluid. The followings are suggested as the postoperative regimen for the patients with laryngoplasty:1. Regular check-up as done for the laryngectomized patient.2. Give a full knowledge of aspiration problems to the patient, and instruct him how to apply a pressure on the anterior neck during food intake.3. Prevention of pulmonary complication by X-ray study of regular intervalThe author also stressed a necessity of development of a new technique in laryngo plasty for the protection of aspiration of food or saliva