Objective effectiveness of and indications for laser-assisted turbinectomy in brachycephalic obstructive airway syndrome

Retrospective evaluation of radiofrequency volumetric tissue reduction for hypertrophic turbinates in dogs with brachycephalic obstructive airway syndrome

OBJECTIVE

The objective of this study was to retrospectively assess the effect of Radiofrequency Volumetric Tissue Reduction (RFVTR) on hypertrophic turbinates and clinical outcome in brachycephalic dogs when included in multi-level surgery (MLS).

STUDY DESIGN

Clinical retrospective multicenter study.

ANIMALS

132 client-owned brachycephalic dogs.

METHODS

132 brachycephalic dogs with high-grade Brachycephalic Obstructive Airway Ayndrome (BOAS) and hypertrophic turbinates were treated with RFVTR as part of MLS of the upper airways. Intranasal obstruction was evaluated by computer tomography (CT) and antero-/retrograde rhinoscopy before and 6 months after RFVTR. The clinical records, the CT images and the rhinoscopy videos were reviewed and clinical evolution was evaluated using a standardized questionnaire. The data was scored semi-quantitatively.

RESULTS

In this study, 132 patients were included for a follow-up period of 120 weeks. RFVTR resulted in minor complications, including serous nasal discharge within the first postoperative week in all dogs, and intermittent nasal congestion between 3-8 weeks after treatment in 24.3% of the patients. Rhinoscopy and CT follow-ups were available for 33 patients. Six months after treatment intranasal airspace was increased (p = 0.002) and the presence and overall amount of mucosal contact points was reduced (p = 0.039).

CONCLUSION

MLS with RFVTR led to a significant reduction in turbinate volume at the 6-month follow-up examination and significant clinical improvement over a long-term period of 120 weeks. This suggests the viability of RFVTR as a turbinate-preserving treatment for intranasal obstruction in dogs with BOAS.

CLINICAL SIGNIFICANCE

RFVTR is a minimally invasive turbinoplasty technique for intranasal obstruction in dogs with BOAS and can be included in MLS without increasing complication rates.

Surgical management of brachycephalic obstructive airway syndrome: An update on options and outcomes

Dogs with a brachycephalic conformation often experience a collection of abnormalities related to their craniofacial conformation, which can lead to a variety of clinical signs such as stertor, exercise intolerance, respiratory distress, and gastrointestinal signs such as regurgitation, among others. This collection of abnormalities is termed brachycephalic obstructive airway syndrome (BOAS). With the rise in popularity of several brachycephalic breeds, veterinarians and veterinary surgery specialists are seeing these dogs with increasing frequency for surgical and medical treatment of these clinical signs, leading to an increased interest in developing surgical techniques for dogs with BOAS and evaluating objective methods of determining outcome after surgery. Advances in anesthetic management including standardized protocols and use of local nerve blocks to decrease opiate use may decrease postoperative complications. A variety of new or modified surgical techniques to manage hyperplastic soft palate and stenotic nares, among other BOAS components, have been developed and studied in recent years. Newer studies have also focused on risk factors for development of major complications in the postoperative period and on objective measurements that may help determine which patients will receive the most benefit from BOAS surgery. In this review, the newest studies focused on updates in anesthetic management, surgical techniques, and postoperative care will be discussed. Additionally, updated information on complication rates and outcomes for dogs undergoing surgical management of BOAS will be included.

Fur Cortisol in French Bulldogs with Different Manifestations of Brachycephalic Obstructive Airway Syndrome

In the present study, 33 French bulldogs with varying degrees of brachycephalic obstructive airway syndrome (BOAS) were evaluated for various parameters to provide evidence of chronic stress in the dogs. For this purpose, an owner interview, a clinical examination, and cortisol concentrations in the fur of the dogs were collected. The median cortisol concentration in the fur of the dogs suffering from BOAS (n = 19) was 0.99 pg/mg (range 0.63-66.18), while that of the control group (n = 14) was 1.13 pg/mg (range 0.3-43.45). However, the statistical analysis did not reveal a statistically significant difference; therefore, it is not possible to distinguish between dogs clinically affected with BOAS and those without clinically relevant signs of the disease. There was no statistically significant difference between the age of the animals and the fur cortisol. None of the owners in the examination and control groups indicated that their dog was suffering from chronic stress which shows that the disease is easily underestimated and remains common. Thus, a thorough clinical examination by an experienced veterinarian remains the gold standard in order to diagnose BOAS.

Comparison of mortality of brachycephalic dogs undergoing partial staphylectomy using conventional incisional, carbon dioxide laser, or bipolar vessel sealing device

OBJECTIVE

To compare mortality of dogs undergoing partial staphylectomy using conventional incisional, carbon dioxide (CO2 ) laser, and bipolar vessel sealing device (BVSD) techniques for the treatment of brachycephalic obstructive airway syndrome (BOAS).

STUDY DESIGN

Retrospective multicenter cohort study.

ANIMALS

A total of 606 client-owned English bulldogs, French bulldogs, and pugs.

METHODS

Medical records from 2011 to 2021 were reviewed for signalment, history, surgical technique, length of hospitalization, and complications. Multivariate statistical analysis was performed to compare odds of mortality between the three techniques of staphylectomy.

RESULTS

The overall mortality rate was 24/606 (4.0%). Of those 24 dogs, staphylectomy was performed with BVSD technique in 13 cases, with CO2 laser in nine, and using conventional incisional technique in two. Nine dogs were graded II or III laryngeal collapse, 14 were graded I, and one was unknown. BVSD technique was associated with mortality prior to discharge compared to the other two techniques (OR = 6.0, 95% CI: 1.3-28.4, p = .023). No differences were detected between conventional incisional and CO2 laser techniques. Concurrent higher grade (stage II or III) laryngeal collapse was independently associated with mortality prior to discharge (OR = 4.6, 95% CI: 1.8-11.8, p = .002).

CONCLUSION

The use of BVSD and grade of laryngeal collapse were associated with a higher risk of perioperative mortality.

CLINICAL SIGNIFICANCE

Clinical studies using a randomized trial design should be conducted to further determine the putative influence of surgical instrumentation in the perioperative mortality rate following multilevel surgery in dogs with BOAS.

Nebulised adrenaline in the post-operative management of brachycephalic obstructive airway syndrome in dogs: short-term outcomes in 90 cases (2014-2020)

CASE HISTORIES

Medical records from a single UK-based referral hospital were retrospectively reviewed to identify brachycephalic dogs who had undergone corrective airway surgery and were nebulised with adrenaline in the post-operative period. Ninety dogs were identified between August 2014 and March 2020.

CLINICAL FINDINGS

Agitation following nebulisation with adrenaline was uncommon, with 86/90 (96%) dogs remaining calm, and overall outcome was reported as satisfactory in 68 of 73 (89%) dogs for which this information was available. Median respiratory rate at T0 (prior to first nebulisation) and T60 (1 hour following nebulisation) were both 20 breaths/minute with a median difference of 0 (95% CI = 0-0) breaths/minute (p = 0.657). Median heart rate at T0 and T60 were both 80 beats/minute with a median difference of 3 (95% CI = -10 to 7) beats/minute (p = 0.948). Two dogs experienced tachycardia, but this was not associated with the timing of administration of adrenaline. Complications reported in the 24 hours following surgery included regurgitation (n = 36), increased respiratory noise and effort (n = 10), aspiration pneumonia (n = 4), and inappetence (n = 3). A temporary tracheostomy tube was placed in 13 (14.4%) dogs.

CLINICAL RELEVANCE

Nebulisation with adrenaline is feasible, results in minimal increases in respiratory rate and heart rate and is associated with agitation in only a small number of dogs.

Effect of conventional multilevel brachycephalic obstructive airway syndrome surgery on clinical and videofluoroscopic evidence of hiatal herniation and gastroesophageal reflux in dogs

OBJECTIVE

To evaluate the effect of conventional multilevel surgery (CMS) for brachycephalic obstructive airway syndrome (BOAS) on associated sliding hiatal hernia (SHH) and/or gastroesophageal reflux (GER).

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Sixteen client-owned dogs with clinical signs consistent with BOAS and associated SHH and GER.

METHODS

All dogs were treated with 1 or more components of CMS including soft palate resection, laryngeal ventriculectomy, and alaplasty. A standardized Dog Swallowing Assessment Tool (Dog SAT) questionnaire was completed by owners preoperatively and postoperatively. Videofluoroscopic swallow studies (VFSS) were used to evaluate esophageal motility, gastroesophageal reflux, and hiatal herniation preoperatively, and in a subset of dogs postoperatively. Upper gastrointestinal endoscopic studies were performed to document esophagitis and lower esophageal sphincter pathology.

RESULTS

All dogs were discharged from the hospital. One dog experienced aspiration pneumonia immediately postoperatively. Owner-assigned clinical scores improved in scores related to regurgitation after eating and regurgitation (P = .012) during increased activity/exercise (P = .002) between preoperative and postoperative time points. However, no improvement was detected in masked assessment of preoperative and postoperative VFSS studies in terms of GER frequency (P = .46) or severity (P = .79), SHH frequency (P = .082) or severity (P = .34) scores.

CONCLUSION

Owners of dogs treated with CMS perceived an improvement in clinical signs of SHH and GER that was not confirmed by VFSS studies.

CLINICAL SIGNIFICANCE

Conventional multilevel surgery in dogs with BOAS does not appear to consistently resolve SHH and GER, although clinical signs may improve.

Prevalence of bronchial wall thickening and collapse in brachycephalic dogs with and without brachycephalic obstructive airway syndrome and in nonbrachycephalic dogs

OBJECTIVE

To assess the prevalence of bronchial wall thickening (BWT) and collapse in brachycephalic dogs with and without brachycephalic obstructive airway syndrome (BOAS) and in nonbrachycephalic dogs.

ANIMALS

85 dogs with no history of lower respiratory tract disease that underwent CT of the thorax.

PROCEDURES

Electronical medical records for March 2011 through August 2019 were reviewed to identify brachycephalic dogs with BOAS (BOAS group) and brachycephalic dogs without BOAS (BDWB group) that did not have any evidence of lower respiratory tract disease and had undergone thoracic CT. A population of nonbrachycephalic dogs of similar weight (control dogs) was also retrospectively recruited.

RESULTS

BWT was identified in 28 of 30 (93.3%; 95% CI, 80.3% to 98.6%) dogs in the BOAS group, 15 of 26 (57.7%; 95% CI, 38.7% to 75.0%) dogs in the BDWB group, and 10 of 28 (35.7%; 95% CI, 20.1% to 54.2%) control dogs. On multivariable analysis, only brachycephalic conformation (P < 0.01) and body weight (P = 0.02) were significantly associated with the presence of BWT. Bronchial collapse was identified in 17 of 30 (56.7%; 95% CI, 39.0% to 73.1%) dogs in the BOAS group, 17 of 26 (65.4%; 95% CI, 46.3% to 81.3%) dogs in the BDWB group, and 3 of 28 (10.7%; 95% CI, 3.1% to 25.9%) control dogs. On multivariable analysis, only brachycephalic conformation was significantly (P < 0.01) associated with the presence of bronchial collapse.

CLINICAL RELEVANCE

A relationship between brachycephalic conformation and body weight with BWT was established, with heavier dogs having thicker bronchial walls. However, further studies are required to investigate the cause. Bronchial collapse was also more common in dogs with brachycephalic conformation, which is in agreement with the previously published literature.

A follow-up study of exercise test results and severity of brachycephalic obstructive airway syndrome signs in brachycephalic dogs

To promote successful breeding against brachycephalic obstructive airway syndrome (BOAS), it is important to assess how BOAS signs progress during young adulthood and how evaluation age and ageing affect the results of chosen breeding selection tools. The aims of this study were to assess how veterinary-assessed and owner-reported BOAS signs and exercise test results change when dogs age. Eight English Bulldogs, 25 French Bulldogs, and 31 Pugs that had undergone previous evaluation were re-examined 2– 3 years later. An owner questionnaire regarding BOAS signs, a veterinary assessment of BOAS severity, and exercise, ie walk tests were re-performed. In Pugs, both 6-min walking distance and 1,000-m time worsened and the initial evaluation age had a significant effect on the 1,000-m time. No significant changes were seen in the results of the French Bulldogs but a negative effect on the 1,000-m time was seen with weight gain. Exercise test statistics were not performed with regard to English Bulldogs due to low sample size. The veterinary-assessed BOAS severity class remained the same in the majority of dogs and the BOAS grade worsened mostly in those dogs that were initially evaluated at less than two years of age. Most owners reported no major changes in BOAS severity. BOAS grading and walk tests were easy to repeat and results remained relatively constant in dogs initially evaluated at over two years of age, supporting the use of these breeding selection tools. However, further, large-scale offspring studies are still needed.

Using thermal effect of 970 nm diode laser to reduce nasal swell body

In recent decades, semiconductor lasers have been successfully used in rhinology. However, their usage in the reduction of the nasal swell body (NSB) is barely studied. Our research aimed to conduct an experimental selection of the laser exposure mode in the NSB zone using a 970 nm diode laser for safe and effective NSB reduction. The thermometric parameters of a diode laser with a wavelength of 970 nm were evaluated in a continuous contact mode of exposure at the power from 2 W to 10 W with 2 W step. The laser was targeted at the liver of cattle, given its similar optical properties to the NSB region. After a series of experiments with every power rate and the analysis of temperature data, we estimated an optimal exposure mode at a power of 4 W. The collected thermometric data demonstrate the safety of this mode in a clinical setting for NSB reduction due to causing no thermal damage to the adjacent tissue. Based on the experiment, a technique for laser reduction of the NSB was developed to improve nasal breathing in patients with severe hypertrophy of this area. The proposed technique was applied to 39 patients with chronic vasomotor rhinitis and the NSB. All patients were divided into 2 groups. Group 1 consisted of 20 patients who underwent surface contact laser-turbinectomy and the NSB reduction using a 970 nm diode laser. Group 2 included 19 patients with the same pathology who underwent laser-turbinectomy, without reduction of the NSB. No statistically significant difference was observed during the dynamic observation with an objective assessment of nasal respiration according to active anterior rhinomanometry when comparing these subgroups with each other according to the t-criterion for independent samples (p > 0.05). As a result of comparing the data obtained on the NOSE scale using the Student's t-test, a statistically significant difference is observed (p < 0.001). Thus, patients who did not perform the reduction of the NSB subjectively noted the insufficiency of nasal breathing. This fact indicates that the NSB is involved in the regulation of airflow.

Abnormal hyoid conformation in French Bulldogs: case report and computed tomographic anatomical comparison

BACKGROUND

Brachycephalic obstructive airway syndrome (BOAS) is common in brachycephalic breeds and comprises multiple anatomic characteristics. Computed tomography (CT) is increasingly used in the preoperative assessment of dogs presenting with BOAS. We describe the case of a French Bulldog with a presumed congenital hyoid malformation and anatomic comparison of hyoid morphology between French Bulldogs and mesaticephalic dogs using CT.

METHODS

Skull CT studies of French Bulldogs and mesaticephalic dogs presenting to two referral hospitals between 2013 and 2020 were collected. The degree of curvature of the basihyoid bone and the relative ventrodorsal thickness (RVD) were determined using a novel measurement technique. A circle of best fit was applied to the inside arc of the basihyoid bone, and the radius and sector angle within the basihyoid bone were recorded. The RVD was defined by the ventrodorsal thickness divided by the width in the frontal plane.

RESULTS

The basihyoid bone of French Bulldogs had a greater mean ± SD RVD of 0.23 ± 0.04 compared to 0.16 ± 0.03 in mesaticephalic dogs (P < 0.01). The sector angle was also greater in French Bulldogs, measuring 144.08 ± 20.88° compared to 103.94 ± 16.49° in mesaticephalic dogs (P < 0.01).

CONCLUSION

This case of hyoid malformation in a French Bulldog reports a rarely documented condition that complicated the management of BOAS. Comparative assessment of hyoid conformation revealed more acute curvature and greater RVD in French Bulldogs than in mesaticephalic dogs. This may represent an additional distorted anatomic component of brachycephalic skull morphology.

[Experimental research of the diode 970 nm laser thermal effect in order to develop a method for reduction of nasal swell body]

OBJECTIVE

To evaluate the thermal effects of a 970 nm diode laser and select the modes necessary for the safe and effective use of this laser to reduce the nasal septum elevation (NSB) in volume in vitro.

MATERIAL AND METHODS

Laser exposure was carried out through a quartz fiber with a diameter of 400 μm in a continuous contact mode at a power from 2 W to 10 W with a step of 2 W. Three linear cuts 1 cm long were applied to the specimens. The distance between the cuts was 0.5 cm. The initial temperature of the fragments was 25.6±1.6°C. Temperature control was carried out from the side of the fragments opposite to the laser action using a certified and verified thermometer with a contact sensor.

RESULTS

In the course of the experiment, it was noted that the optimal power for effectively and safely reducing the area of the nasal septum elevation is 4 W. The maximum heating temperature reached 38.6±4.7°C.

CONCLUSIONS

A semiconductor laser with a wavelength of 970 nm can be used to reduce the elevation of the nasal septum, as it leads to predictable results, allowing you to control thermal effects and damage to surrounding tissues.

Nebulization of epinephrine to reduce the severity of brachycephalic obstructive airway syndrome in dogs

OBJECTIVE

To determine the preoperative and postoperative effect of nebulized epinephrine on brachycephalic obstructive airway syndrome (BOAS) severity in dogs.

STUDY DESIGN

Prospective clinical study.

SAMPLE POPULATION

Thirty-one client-owned pugs, French bulldogs, and English bulldogs with moderate to severe BOAS.

METHODS

Whole body barometric plethysmography was used to determine BOAS severity (BOAS index; 0%-100%) prior to and after nebulization with 0.05 mg/kg epinephrine diluted in 0.9% saline preoperatively. The same protocol was repeated postoperatively (within 24 hours of surgery).

RESULTS

Five dogs were excluded because they did not tolerate nebulization, and postoperative data were available for 13 dogs. Epinephrine nebulization resulted in a decreased BOAS index across all breeds of dog both before (9.6% [3.1% to -30.2%], n = 26) and after surgery (14.3% [0.9% to -24.3%], n = 13). The preoperative reduction in BOAS index was greater (17.3% [1.8% to -27.4%]) in dogs with a baseline BOAS index >70% (P = .006) and in pugs (16.9% [0.8% to -27.4%]) compared with French bulldogs (5.2% [3.1% to -30.2%], P = .03). Simple linear regression was used to identify a positive relationship between baseline BOAS index and reduction in BOAS index for pugs (n = 10, P = .001). Nausea was noted as a side effect in four dogs.

CONCLUSION

Nebulized epinephrine reduced the BOAS index of dogs in this study. This effect was clinically significant in preoperative dogs with a BOAS index >70% and in dogs recovering from surgery.

CLINICAL SIGNIFICANCE

This study provides evidence to support the use of nebulized epinephrine in the perioperative management of BOAS-affected dogs.

Evaluation of metabolic profile and C-reactive protein concentrations in brachycephalic dogs with upper airway obstructive syndrome

Background

Brachycephalic dogs have abnormal breathing patterns similar to those in humans with obstructive sleep apnea syndrome. Obstructive sleep apnea syndrome is associated with dyslipidemia, hyperglycemia, and insulin resistance. Despite the fact that anatomic and functional alterations are well described in brachycephalic dogs, little is known about the consequences of upper airway obstruction on systemic inflammatory response and metabolic profile.

Objectives

To describe history, clinical presentation, and anatomic abnormalities; to evaluate systemic inflammatory response and metabolic profile; and to identify possible associations among clinical signs, anatomic abnormalities, inflammatory response, and metabolic profile in brachycephalic dogs with airway obstruction.

Animals

Thirty purebred brachycephalic dogs with brachycephalic airway obstructive syndrome (BAOS).

Methods

Prospective study. The following information was recorded and studied: respiratory and digestive signs, airway and digestive endoscopic anomalies, presence or absence of tracheal hypoplasia, histologic evaluation of gastrointestinal tract biopsy specimens, serum concentrations of C‐reactive protein (CRP), fructosamine, insulin, glucose, triglyceride, cholesterol, and plasma concentrations of lipoprotein classes.

Results

A high proportion of dogs (76.7%) had gastrointestinal signs. Esophageal deviation, atony of the cardia of the stomach, and distal esophagitis were the most common endoscopic anomalies detected. Twenty‐six (86.6%) dogs had different degrees of laryngeal collapse. Gastrointestinal histologic evaluation identified mostly chronic inflammation. Glucose, fructosamine, triglycerides, cholesterol, CRP, pre‐beta, beta lipoproteins, and chylomicrons were increased to a variable extent. Significant associations among clinical signs, anatomic abnormalities, CRP, and metabolic profile were not found.

Conclusion and Clinical Importance

Despite the presence of inflammation and some mild metabolic derangements, the clinicopathological variables evaluated did not offer valuable information in dogs with BAOS.