Intraoperative evaluation of the larynx following unilateral arytenoid lateralization for acquired idiopathic laryngeal paralysis in dogs

Anatomic characterization of the location of the esophageal ostium relative to the rima glottidis on CT in adult Labrador Retrievers

OBJECTIVE

To characterize the anatomic location of the esophageal ostium relative to the rima glottidis in adult Labrador Retrievers with the use of CT.

ANIMALS

98 CT scans of 75 adult Labrador Retrievers.

PROCEDURES

A search of the medical records database identified records of Labrador Retrievers that underwent CT of the head and neck between January 1, 2015, and December 31, 2018. Evaluators, blinded to each other's results, reviewed CT images and measured esophageal area at the level of the rima glottidis. For each dog, the left esophageal percentage (LEP) was calculated as the esophageal area left of the rima glottidis midline divided by the overall esophageal area at that level. Variables (age, sex, patient position, intubation status, and maxillary support during CT) were evaluated for association with LEP. The CT images of dogs that had multiple scans were assessed for within-patient variance.

RESULTS

Mean LEP was 56.2 ± 18.1% for all dogs. Only right lateral recumbency was significantly associated with LEP, with a lower LEP for dogs positioned in right lateral recumbency (42.4 ± 12.7%), compared with left lateral (63.0 ± 7.4%) or sternal (57.3 ± 18.8%) recumbency. No association was detected between LEP and other variables assessed. Eleven dogs had multiple CT scans; within-patient variance for LEP was ± 26.6%.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that, although most dogs had an LEP > 50%, the esophageal ostium was fairly centrally located in most dogs and may be more mobile than previously thought. Additional research is warranted to assess this mobility and whether the esophageal ostium location, relative to the larynx, affects the incidence of aspiration pneumonia in dogs undergoing surgical treatment for geriatric-onset laryngeal paralysis and polyneuropathy.

Effect of doxepin on quality of life in Labradors with laryngeal paralysis: A double-blinded, randomized, placebo-controlled trial

Background

Laryngeal paralysis commonly affects older Labrador retrievers. Currently, dogs with severe disease require surgical intervention, most commonly arytenoid lateralization. Anecdotally, doxepin has been proposed to help dogs with laryngeal paralysis.

Hypothesis

Doxepin will improve quality of life measures assessed by owners of Labrador retrievers with laryngeal paralysis not requiring emergency surgery.

Animals

Twenty‐two Labrador retrievers with laryngeal paralysis.

Methods

Dogs were randomized to receive doxepin (3‐5 mg/kg q12h PO) or placebo for 28 days. Owners completed quality‐of‐life assessments before and after completing the study. Data were compared between groups using Rank‐Sum tests or Fisher's exact tests.

Results

The 2 groups of dogs did not differ at baseline except for owner‐perceived degree of ataxia (owners of dogs receiving doxepin considered them more ataxic than owners of dogs receiving placebo). After 28 days, owner‐assessed quality of life measures did not differ between dogs receiving doxepin or placebo (dogs worsening: doxepin = 2, placebo = 1; dogs unchanged: doxepin = 6, placebo = 7; dogs improved: doxepin = 4, placebo = 2; P = .84). Dogs receiving placebo had a greater improvement in client‐assessed overall health than dogs receiving doxepin (mean ranks: doxepin = 4.36, placebo = 6.64; P = .04). The study was terminated at this interim analysis.

Conclusions and Clinical Importance

Doxepin did not appear to improve any measures of owner‐assessed quality of life in Labrador retrievers with laryngeal paralysis.

Evaluation of Translaryngeal Percutaneous Arytenoid Lateralization (TPAL) in dogs with experimentally created laryngeal paralysis

The aim of this experimental study was to evaluate the effect of Translaryngeal Percutaneous Arytenoid Lateralization (TPAL) in dogs with experimentally created laryngeal paralysis. All dogs (n=5) underwent bilateral recurrent laryngeal neurectomy before TPAL. Two TPAL suture techniques were evaluated. TPAL-CranialCaudal (TPAL-CC) was performed first, followed 11 to 14days later by TPAL-DorsalVentral (TPAL-DV). For both techniques, a mattress suture was placed through the arytenoid cartilage via an oral approach. Laryngeal examination was performed before, immediately after, and on days 1, 3 and 7 for both TPAL techniques. Ipsilateral hemiglottic surface area and the degree of laryngeal swelling or reaction to the suture were recorded. Laryngeal tissue was evaluated by histopathology at the end of the study. For both TPAL techniques, hemiglottic surface area was increased immediately after suture placement (P<0.05). At all other times, hemiglottic area was not statistically different from preoperative value (P>0.05). TPAL-DV resulted in less laryngeal swelling compared to TPAL-CC. Histopathology of the arytenoid cartilage surrounding the mattress suture revealed mucosal ulceration and inflammation consistent with the presence of the suture material. Both TPAL techniques were effective at lateralizing the arytenoid cartilage and significantly increasing hemiglottic surface area immediately after suture placement. However, mucosal swelling and loss of tension on the mattress suture lead to a decrease in glottic area within 24h. Further refinements in suture placement technique are warranted to minimize swelling and improve the duration of arytenoid lateralization prior to clinical application.

Comparison of bacterial cultures of the larynx between dogs with laryngeal paralysis and normal dogs

OBJECTIVE

To document the most common types of bacteria isolated from the canine larynx and to compare isolates, degree of growth and susceptibility patterns between dogs with laryngeal paralysis and dogs with normal laryngeal function.

METHODS

Laryngeal swabs were collected from each patient and submitted for bacterial culture and susceptibility testing. Dogs with laryngeal paralysis (n=23) underwent a unilateral arytenoid lateralisation and control dogs (n=24) underwent an elective orthopaedic procedure. Results of the cultures were compared between groups.

RESULTS

Bacterial organisms isolated from the larynx were similar to those normally found in the oropharynx, trachea and lungs. The most common bacteria isolated from the larynges of all dogs were Escherichia coli, Klebsiella species and Pasteurella species. Pure colonies were more commonly seen in dogs with laryngeal paralysis while mixed colonies were more commonly seen in control dogs. Antimicrobial resistance was similar between study and control dogs.

CLINICAL SIGNIFICANCE

The laryngeal flora appears to contain bacteria that are commonly isolated from the oropharynx, trachea and lungs. Differences in antimicrobial susceptibility were not identified between study and control dogs.

Idiopathic Canine Laryngeal Paralysis as One Sign of a Diffuse Polyneuropathy: An Observational Study of 90 Cases (2007-2013)

OBJECTIVE

To determine survival and incidence of complications in dogs with idiopathic laryngeal paralysis (ILP) and concurrent neurologic signs.

STUDY DESIGN

Observational study.

ANIMALS

Dogs (n = 90) with ILP.

METHODS

Medical records (January 2007-June 2013) of dogs with ILP were reviewed. Neurologic comorbidities, including pelvic limb neurologic abnormalities and esophageal abnormalities were identified. Using medical record information and client interviews, the relationship between these comorbidities and postoperative survival (primary outcome measure) and postoperative complications (secondary outcome measure) was identified.

RESULTS

Dogs that had surgical correction of ILP had a 2.6-fold reduction in the hazard of death throughout the study period (HR = 2.6; 95% CI: 1.34-4.84, P = .006). Owner assessed patient quality of life (10-point scale) increased by an average of 4.1 ± 1.4 units immediately postoperatively, and 4.9 ± 0.9 units until death or followup compared with preoperative values. Thirty-five of 72 dogs available for followup had evidence of diffuse neurologic comorbidities. Overall complication rate for dogs with neurologic comorbidities was 74%, compared with 32% for dogs without neurologic comorbidities. Presence of any neurologic comorbidity was associated with a significantly greater odds of any complication (OR = 4.04; 95% CI: 1.25-13.90, P = .019) as well as recurring complications (OR = 8.00; 95% CI: 1.49-54.38; P = .015).

CONCLUSION

Surgical correction of ILP was positively associated with survival, and dogs with neurologic comorbidities were at greater risk for developing postoperative complications.

Minimally invasive unilateral arytenoid lateralization in dogs: A cadaveric study

The aim of this study was to develop a minimally invasive thyroarytenoid lateralization technique (MITAL). Eleven unilateral MITAL procedures were performed on 11 canine cadavers. Two hypodermic needles were passed through the skin into the lumen of the larynx, penetrating the thyroid and arytenoid cartilages. Suture material was passed through the needles to lateralize the arytenoid cartilage. A rigid endoscope was used to visualize needle insertion and suture material placement. A key-hole approach to the larynx was performed and the suture material was knotted on the lateral aspect of the thyroid cartilage. The change in the rima glottidis area was recorded as were the duration of the procedure and complications encountered. The landmarks for needle insertion were easily palpated, and a significant increase in the area of the rima glottidis was documented after performing unilateral MITAL. In conclusion, unilateral MITAL is a quick, minimally invasive procedure which increases the area of the rima glottidis in cadaveric dogs.

Intralaryngeal thyroarytaenoid lateralisation using the Fast-Fix 360 system: a canine cadaveric study

Introduction

Laryngeal paralysis is a condition in which failure of arytaenoid abduction results in a reduced rima glottidis cross-sectional area. The most commonly performed surgical techniques rely on unilateral abduction of the arytaenoid, requiring a lateral or ventral surgical approach to the larynx.

Aims and objectives

The aim of the study was to investigate a novel minimally invasive intralaryngeal thyroarytaenoid lateralisation technique, using the Fast-Fix 360 meniscal repair system.

Materials and methods

Larynges were harvested from large breed canine cadavers. With the aid of Kirschner wires placed between the centre of the vocal process and the centre of an imaginary line between the cranial thyroid fissure and the cricothyroid articulation, the mean insertion angle was calculated.

Results

The Fast-Fix 360 delivery needle inserted intralaryngeally (n=10), according to a simplified insertion angle (70°), resulted in thyroid penetration (>2.5 mm from margin) in all patients. The Fast-Fix was applied unilaterally at 70° with the first toggle fired on the lateral aspect of the thyroid cartilage and inside the laryngeal cavity on retraction. The suture was tightened. Preprocedural (61.06±9.21 mm2) and postprocedural (138.37±26.12 mm2) rima glottidis cross-sectional area was significantly different (P<0.0001). The mean percentage increase in rima glottidis cross-sectional area was 125.96 per cent (±16.54 per cent).

Conclusion

Intralaryngeal thyroarytaenoid laterlisation using the Fast-Fix 360 meniscal repair system ex vivo increased the rima glottidis cross-sectional area significantly.

Laryngeal disease in dogs and cats

The most common disease process involving the larynx is laryngeal paralysis, which occurs much more frequently in dogs than in cats. Diagnosis of laryngeal paralysis requires close attention to anesthetic plane and coordination of respiratory effort with laryngeal motion. Surgical arytenoid lateralization improves respiration and quality of life in dogs with laryngeal paralysis; however, aspiration pneumonia is a recognized complication, and generalized neuropathy can progress. Laryngeal collapse can result from any cause of chronic upper airway obstruction, but is most often associated with unaddressed brachycephalic airway syndrome. Laryngeal neoplasia, while generally uncommon, occurs more frequently in cats than in dogs.

Less invasive unilateral arytenoid lateralization: a modified technique for treatment of idiopathic laryngeal paralysis in dogs: technique description and outcome

OBJECTIVE

To (1) describe a modification of conventional unilateral cricoarytenoid lateralization (UCAL), called less-invasive unilateral cricoarytenoid lateralization (LI-UCAL) for treatment of idiopathic laryngeal paralysis (LP); (2) report clinical outcome of LI-UCAL; and (3) describe the effect of early discharge after surgery.

STUDY DESIGN

Retrospective clinical study.

ANIMALS

Dogs (n = 22).

METHODS

Medical records (January 2009 to October 2011) of dogs diagnosed with idiopathic LP that had LI-UCAL were reviewed. Signalment, clinical signs, laboratory tests, imaging, concurrent medical conditions, information from the anesthesia record, and hospitalization time were documented. Follow-up was obtained by direct examination, questionnaire, and review of medical records from referring veterinarians.

RESULTS

Dogs included in the study had variable degrees and duration of respiratory distress before surgery. Median surgery time was 32 minutes. Median hospitalization was 6 hours, and median follow-up was 427 days. Long-term respiratory function, as reported by owners at last follow-up, improved in 95.5% of dogs after surgery; exercise tolerance improved by 90%. Major complications included death secondary to aspiration pneumonia (9%), aspiration pneumonia from which dogs recovered within 3 days after administration of antimicrobials (9%), and development of right-sided laryngeal collapse that required right sided LI-UCAL (4.5%). At long-term follow-up, 95.5% of owners were satisfied with the surgical outcome.

CONCLUSION

LI-UCAL is a feasible surgical technique and resulted in improvement of clinical signs related to LP. Calm recoveries without adverse effects such as respiratory distress were associated with early discharge. LI-UCAL could be considered an alternative to conventional UCAL.

Video-assisted unilateral cricoarytenoid laryngoplasty in 14 dogs with bilateral idiopathic laryngeal paralysis

BACKGROUND

Unilateral cricoarytenoid laryngoplasty is commonly performed for treatment of idiopathic laryngeal paralysis in dogs. Determination of the appropriate tension applied to the suture can be difficult, particularly for the novice surgeon.

OBJECTIVE

To describe a technique for video-assisted unilateral cricoarytenoid laryngoplasty (VAUCAL) and to report short-term outcome in dogs undergoing VAUCAL.

ANIMALS AND METHODS

Dogs (n = 14) with bilateral idiopathic laryngeal paralysis undergoing VAUCAL between August 2011 and May 2013 were evaluated. A cricoarytenoid suture was tensioned under video observation of the rima glottidis using a 5-mm rigid endoscope. Real-time visualization of arytenoid abduction during suture tensioning, and final arytenoid position were assessed. Requirement for additional intravenous anesthestic, intra- and post-operative complications and short-term outcomes were documented.

RESULTS

Adequate, real-time visualization of the larynx during tensioning of the cricoarytenoid suture was accomplished in 13/14 dogs. Additional intravenous anesthesia was required in 5/14 dogs to facilitate reintubation. Final arytenoid position was considered inadequate in two dogs on post-operative trans-oral laryngeal examination. Recurrence of clinical signs occurred in one dog three months following initial surgery. Owner outcome was deemed good (n = 8) or excellent (n = 6).

CONCLUSIONS

VAUCAL is a feasible technique to permit direct real-time visualization of the larynx during tensioning of the cricoarytenoid suture, and enables assessment of final arytenoid position intra-operatively by the operating surgeon.

CLINICAL IMPORTANCE

VAUCAL allows the operating surgeon to assess arytenoid abduction intra-operatively, at the time of knot placement. This technique may be particularly useful for the novice surgeon or surgeon in training.