The impact of tongue dimension on air volume in brachycephalic dogs

Laser-Assisted Turbinectomy in Dogs

This article discusses the laser-assisted turbinectomy (LATE) procedure and indications for its performance in dogs suffering from brachycephalic obstructive airway syndrome (BOAS). The article summarizes landmark works that reported, for the first time, endoscopic-assisted identification and treatment of structures within the brachycephalic nose that contribute to intranasal obstruction and resistance to breathing, specifically hypertrophic and aberrant nasal turbinates. Brachycephaly is discussed in the context of how these aberrations form and how definitive treatments such as LATE and adjunctive treatments such as ala vestibuloplasty, folded flap palatoplasty, and others may ameliorate the negative effects and improve patient outcomes associated with aberrant intranasal conchal configurations.

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.

Non-brachycephalic dogs with stertor have higher nasopharyngeal collapsibility compared with dogs without stertor and foramen lacerum level is ideal for evaluating nasopharyngeal collapse on dynamic CT

Stertor, a clinical sign associated with obstructive airway syndrome, is often observed in non-brachycephalic dogs. This prospective, case-control study aimed to compare soft palate dimensions, nasopharyngeal cross-sectional area (CSA), and nasopharyngeal collapsibility at various locations in non-brachycephalic dogs with and without stertor. A total of 50 dogs were recruited and stratified into control (n = 34) and stertor (n = 13) groups. Static and dynamic computed tomography was conducted without tracheal intubation, and the following variables were calculated: normalized soft palate length and thickness, normalized maximum and minimum nasopharyngeal CSAs (rCSAmax and rCSAmin), and nasopharyngeal collapsibility at the level of the cranial end of the soft palate, pterygoid hamulus, foramen lacerum, bony labyrinth, and caudal end of the soft palate. The stertor group demonstrated significantly lower rCSAmax and rCSAmin, as well as higher nasopharyngeal collapsibility compared with the control group, while no significant differences were noted in the soft palate dimension. Evaluating nasopharyngeal collapse at the foramen lacerum level was recommended due to the clear presence of identifiable bony landmarks and lower overlap in the nasopharyngeal collapsibility between dogs with and without stertor. Physical dimensions of the soft palate may not be the primary contributing factor to nasopharyngeal collapse and clinical signs in non-brachycephalic dogs.

Evaluation of risk factors for sleep-disordered breathing in dogs

BACKGROUND

Brachycephalic dogs display sleep-disordered breathing (SDB). The risk factors for SDB remain unknown.

OBJECTIVES

To identify risk factors for SDB. We hypothesized that brachycephaly, increasing severity of brachycephalic obstructive airway syndrome (BOAS), excess weight, and aging predispose to SDB.

ANIMALS

Sixty-three privately owned pet dogs were prospectively recruited: 28 brachycephalic and 35 normocephalic (mesaticephalic or dolicocephalic) dogs.

METHODS

Prospective observational cross-sectional study with convenience sampling. Recording with the neckband was done over 1 night at each dog's home. The primary outcome measure was the obstructive respiratory event index (OREI). Body condition score (BCS) was assessed, and BOAS severity was graded for brachycephalic dogs.

RESULTS

Brachycephaly was a significant risk factor for high OREI value (ratio of the geometric means 5.6, 95% confidence interval [CI] 3.2-9.9; P < .001) but aging was not (1.1, 95% CI 1.0-1.2; P = .2). Excess weight, defined as a BCS of over 5/9, (3.5, 95% CI 1.8-6.7; P < .001) was a significant risk factor. In brachycephalic dogs, BOAS-positive class (moderate or severe BOAS signs) was a significant risk factor (2.5, 95% CI 1.1-5.6; P = .03).

CONCLUSIONS AND CLINICAL IMPORTANCE

Brachycephaly decreases welfare in a multitude of ways, including disrupting sleep. Brachycephaly, increasing severity of BOAS and excess weight are risk factors for obstructive SDB.

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.

The effect of the surgical treatment of brachycephalic obstructive airway syndrome on the thermoregulatory response to exercise in French bulldogs: a pilot study

Introduction

Due to altered anatomy of the upper respiratory tract, brachycephalic dogs exhibit increased airway resistance and reduced surface area for evaporative heat loss, predisposing them to respiratory and thermoregulatory problems, a syndrome referred to as Brachycephalic Obstructive Airway Syndrome (BOAS). Compared to non-brachycephalic dogs, brachycephalic breeds are more susceptible to heat-related injuries even at low ambient temperatures and relatively low physical activity levels. Surgical treatment alleviates clinical signs, potentially improving dogs' thermoregulatory ability with BOAS. Our study aimed to investigate the thermoregulatory response in French bulldogs before and after the surgical correction of BOAS, respectively.

Methods

Thirteen dogs were exposed to dynamic exercise on a treadmill and the dynamics of their rectal temperature (RT) and heart rate (HR) was measured. The experiment was performed in two independent sessions, before and after the surgical treatment. The test consisted of two consecutive 5-min walks at a speed of 2.5 km/h, first at an inclination of 0% and the second at an inclination of 5%, and a 30-min recovery period. Rectal temperature and HR were measured before the start of the test (t0), at the end of the first (t1) and the second part (t2), and 15 min (t3) and 30 min (t4) in the recovery.

Results

A significant increase in RT and HR was observed during exercise and recovery compared to the resting values, implying that the exercise intensity was sufficient to challenge the thermoregulatory response. The increase of RT was significantly lower during both parts (t1: p  = 0.004; t2: p  <  0.001) of exercise after the surgical treatment than before the treatment. Although a trend of lower RT after recovery was observed compared to before the surgery, it did not reach statistical significance. Similarly to RT, the HR was significantly lower during exercise after the first (p  =  0.020) and the second part (p  =  0.011) of exercise after the surgery compared to before the surgery but did not reach significance in the recovery.

Conclusion

Surgical treatment of BOAS can improve thermoregulation during exercise in French bulldogs with BOAS.

Differences in selected blood parameters between brachycephalic and non-brachycephalic dogs

Introduction

Cranial and upper-airway anatomy of short-nosed, flat-faced brachycephalic dogs predisposes them to brachycephalic obstructive airway syndrome (BOAS). Periodic apnoea increased inspiratory resistance, and an inability to thermoregulate effectively are characteristic of BOAS, but internationally accepted objective markers of BOAS severity are missing. The objective of this study was to compare the selected blood parameters between non-brachycephalic (NC) and brachycephalic (BC) dogs, exploring the possibility of developing a blood test for BOAS severity grading in the future.

Methods

We evaluated blood biochemistry, complete blood cell counts, red blood cell (RBC) indices, reticulocyte counts, a blood-born marker of intermittent hypoxia (glutathione, NO production), RBC hydration, deformability, and blood markers of metabolic changes and stress between BC (n = 18) and NC (meso- and dolichocephalic, n = 22) dogs.

Results

Reticulocyte counts and the abundance of middle-fluorescence immature reticulocytes were significantly (p < 0.05) higher in BC dogs compared to NC dogs. BC dogs had significantly more NO-derived NO2 - /NO3 - in plasma than NC dogs. RBCs of BC dogs were shedding significantly more membrane, as follows from the intensity of eosin maleimide staining, and had a significantly higher mean corpuscular hemoglobin concentration than NC dogs. Intracellular reduced glutathione content in RBCs of BC dogs was significantly lower, while plasma lactate was significantly higher in BC dogs compared to NC dogs. Plasma cholesterol and triglycerides were significantly lower, and cortisol was significantly higher in BC dogs compared to NC dogs. Eosinophil counts were significantly lower and the neutrophil-to-lymphocyte ratio was higher in BC dogs compared to NC dogs.

Discussion

Taken together, our findings suggest that the brachycephalic phenotype in dogs is associated with alterations at the level of blood cells and, systemically, with oxidation and metabolic changes. The parameters identified within this study should be further investigated for their potential as objective indicators for BOAS.

Influence of feline brachycephaly on respiratory, gastrointestinal, sleep, and activity abnormalities

OBJECTIVE

To determine the influence of brachycephaly on respiratory, gastrointestinal, sleep, and activity-related parameters in cats.

STUDY DESIGN

Prospective questionnaire-based study.

ANIMALS

A total of 194 BC and 1003 non-BC cats.

METHODS

Owners completed an online questionnaire regarding respiratory, gastrointestinal, sleep, and activity-related parameters. Response options were scored, and individual scores summed to give a total clinical severity score for each cat.

RESULTS

Brachycephalic cats had more frequent snoring (odds ratio [OR] 6.89; 95% confidence interval [CI]: 5.06-9.41), sneezing (OR 6.52; CI: 4.75-8.98), nasal discharge (OR 8.26; 95% CI 5.77-11.85), coughing (OR 1.75; CI: 1.17-2.59), and dyspnea (OR 5.32; CI: 3.42-8.28); shorter activity before becoming dyspneic (OR 2.71; CI: 1.93-3.79), slower recovery from activity (OR 3.17; CI: 2.19-4.57), lower activity levels (OR 2.16; CI: 1.59-2.95), and increased respiratory noise (OR 6.68; CI: 4.71-9.52); and more hypersalivation (OR 2.50; CI: 1.47-4.16), halitosis (OR 1.40; CI: 1.00-1.95), and difficulty chewing (OR 5.19; CI: 3.65-7.38). Median clinical severity scores were higher for BC cats than non-BC cats (p < .0001).

CONCLUSIONS

Brachycephalic cats (BC) were at risk for respiratory, gastrointestinal, and activity-related symptoms compared to non-BC cats.

CLINICAL RELEVANCE

Some BC cats exhibit clinically relevant symptoms and behaviors as reported by owners. Medical or surgical interventions may improve these symptoms and warrant investigation.

Ala vestibuloplasty improves cardiopulmonary and activity-related parameters in brachycephalic cats

OBJECTIVE

To evaluate the effects of ala vestibuloplasty on cardiopulmonary and lifestyle-related parameters in brachycephalic (BC) cats.

STUDY DESIGN

Prospective cohort.

ANIMALS

Client-owned BC cats (n = 19).

METHODS

Cats were assessed preoperatively by airway computed tomography (CT), endoscopy, contrast echocardiography, cardiac biomarkers, and structured owner questionnaire. Ala vestibuloplasty was performed bilaterally, and blood values, imaging, and owner questionnaire responses were re-evaluated 8-20 weeks postoperatively.

RESULTS

Cats were presented for predominantly respiratory clinical signs attributable to brachycephaly. Preoperatively, all cats had stenotic nares, prolonged normalized pulmonary transit time (nPTT) (mean 5.43 ± 1.10 s), and a hyperattenuating pulmonary pattern. No complications occurred following surgery. Postoperatively, nPTT (mean 3.89 ± 0.74 s, p < .001) and frequencies of sneezing (p = .002), snoring (p = .006), open-mouth breathing (p = .0004), and nasal discharge (p = .019) were decreased. Cats exhibited increased activity (p = .005), less frequent dyspnea during activity (p < .001), longer duration of activity before becoming dyspneic (p = .002), faster recovery from activity (p < .001), and decreased respiratory noise (p < .001). Median questionnaire scores improved from preoperative to postoperative (p < .001).

CONCLUSION

Anatomic, echocardiographic, and CT changes were common in this cohort of clinically affected BC cats. Pulmonary blood flow and respiratory function were improved after surgery.

CLINICAL SIGNIFICANCE

Stenotic nares are the predominant airway abnormality in BC cats. Ala vestibuloplasty is a safe procedure that improves cardiac and CT abnormalities and respiratory and other clinical signs in BC cats.

CT volumetric analysis permits comparison of tongue size and tongue fat in different canine brachycephalic and mesaticephalic breeds

While macroglossia is a newly accepted component of brachycephalic obstructive airway syndrome (BOAS) in dogs, macroglossia with increased tongue fat is a well-known cause for obstructive sleep apnea (OSA) in people, and targeted reduction procedures such as midline glossectomy are used to treat people with OSA. While midline glossectomy has been described in dogs, tissue contributions to macroglossia have not been characterized. The purpose of this retrospective, descriptive, case-control study was to describe and compare volumetric dimensions of the tongue and tongue fat in brachycephalic (BC) and mesaticephalic (MC) dogs using CT images. Data collected included head and neck CT images from 17 BC and 18 control MC dogs. Multiplanar reformatted and 3D reconstructed images were created using image segmentation and specialized visualization software to calculate volumetric dimensions of the total tongue, tongue fat, and tongue muscle. Rostral and caudal topographical distributions of fat were compared. Total tongue and tongue muscle volume (P < 0.0001) and tongue fat volume (P = 0.01) normalized to body weight (BW) were greater in BC dogs. More fat was localized in the caudal tongue in both groups (P < 0.04). In regression analysis, BC conformation and increased weight were significant predictors of increased tongue fat volume. As in people, increased tongue fat may contribute to macroglossia and sleep-disordered breathing in BC dogs. Use of CT volumetry to identify tongue fat deposits may permit targeted surgical reduction of tongue volume in BC dogs and contribute substantially to treatment of BOAS.

Wound healing complications following folded flap palatoplasty in brachycephalic dogs

OBJECTIVE

To determine the incidence and characteristics of wound healing complications after folded flap palatoplasty (FFP).

METHODS

Prospective study of 25 dogs that underwent FFP as a component of corrective multilevel surgery for brachycephalic obstructive airway syndrome. Oropharyngeal re-examination was conducted after a minimum of 28 days post-operatively, unless indicated earlier by the onset of clinical signs.

RESULTS

Wound healing complications occurred in nine dogs (36%). Minor and major wound complications were diagnosed at a median of 36 days (1.5-51 days) post-operatively. Eight dogs had major wound complications, four of which showed no associated clinical signs. Two patterns of major wound complications were observed: incisional dehiscence (ID) with caudal retraction of the soft palate mucosa and development of a full-thickness defect (FTD) in the centre of the soft palate. Revision of the soft palate surgery was performed in five dogs, failing again in one dog with ID. Clinical signs resolved in symptomatic dogs after revision surgery to close FTD.

CONCLUSION

In this study, wound healing complications were common after FFP and were not associated with significant clinical deterioration. Further research is necessary to determine the value and timing of routine post-operative oropharyngeal examination for assessment of soft palate healing after FFP as well as the indication for and success of approaches to the management of wound healing complications. The two distinct patterns of FFP failure recognised may provide insight into the underlying causes and lead to refinements in folded flap palatoplasty technique.

Severity of nasopharyngeal collapse before and after corrective upper airway surgery in brachycephalic dogs

OBJECTIVE

To determine the severity of nasopharyngeal collapse in brachycephalic dogs before and after corrective airway surgery.

ANIMALS

Twenty-three brachycephalic dogs (21 with clinical signs referrable to the upper airway) and nine clinically normal nonbrachycephalic dogs (controls).

METHODS

Dogs were evaluated with fluoroscopy awake and standing with the head in a neutral position. The magnitude of nasopharyngeal collapse was measured as the maximum reduction in the dorsoventral dimension of the nasopharynx during respiration and expressed as a percentage. Brachycephalic dogs were anesthetized, the airway evaluated, and corrective upper airway surgery (alaplasty, staphylectomy, sacculectomy, tonsillectomy) was performed. A cohort (n = 11) of the surgically treated brachycephalic dogs had fluoroscopy repeated a minimum of 6 weeks after surgery.

RESULTS

Median preoperative reduction in the dorsoventral dimensions of the nasopharynx was greater in brachycephalic dogs (65%; range: 8-100%) than in controls (10%; range: 1-24%, p = .0001). Surgery did not improve the reduction in dorsoventral diameter of the nasopharynx during respiration in brachycephalic dogs (n = 11) postoperatively (p = .0505).

CONCLUSION AND CLINICAL SIGNIFICANCE

Nasopharyngeal collapse was a common and sometimes severe component of brachycephalic airway obstruction syndrome in the cohort of dogs evaluated. The lack of significant postoperative improvement may represent a type II error, a failure to adequately address anatomical abnormalities that increase resistance to airflow, or inadequate upper airway dilator muscle function in some brachycephalic dogs.

Comparison of harmonic shears, diode laser, and scissor cutting and suturing for caudal palatoplasty in dogs with brachycephalic obstructive airway syndrome

Traditionally, staphylectomy has been performed using scissors cutting and suturing. Alternative surgical techniques such as staphylectomy with monopolar electrocoagulation, CO₂ or diode laser, bipolar vessel sealing device and harmonic shears have also been described. The purpose of this prospective study was to compare the difference in surgical time, intraoperative haemorrhage and histological damage between staphylectomy performed with harmonic shears (HSS), diode laser (DLS) and traditional scissor 'cutting and suturing' technique with Metzenbaum scissors (SIS). Group HSS included 17 dogs, whereas Group DLS and Group SIS included 10 dogs each. Double masked histological evaluation was performed on the excised specimens. The harmonic shears resulted in the shortest surgical times (HSS 46 s, DLS 300 s, SIS 360 s; P < 0.001). There was a difference in the intraoperative haemorrhage among the three techniques; intraoperative haemorrhage did not occur in HSS and DLS groups. HSS was associated with more frequent damage involving the connective tissue (P = 0.001), muscle (P = 0.038), salivary gland tissue (P < 0.001), but less oedema was observed (P < 0.001). HSS was the fastest of the techniques evaluated for caudal elongated soft palate resection, resulting in less tissue oedema, and no intra-operative haemorrhage. These characteristics might result in reduced postoperative swelling and airway obstruction compared to other techniques.

Management of Dental and Oral Developmental Conditions in Dogs and Cats

Developmental dental and oral disorders are present in juvenile patients less than 12 months of age. The conditions are diverse ranging from cosmetic only to requiring advanced surgical intervention to alleviate pain and secondary complications. Clinical presentation, diagnosis, and appropriate treatment of dental abnormalities including abnormalities in the number, structure, size, and shape of teeth, as well as oral abnormalities including malocclusions, congenital cleft lip and palate, developmental abnormalities resulting in bony proliferation, and soft-tissue abnormalities of the lip and tongue are discussed throughout the article.

3T MRI characteristics of the palatine tonsil in brachycephalic dogs

OBJECTIVE

Investigation of the MRI characteristics of the palatine tonsil in brachycephalic dogs in 3T high-field system.

MATERIAL AND METHODS

Eighty-five brachycephalic dogs and 37 normocephalic dogs were divided into five groups: group 1 French bulldogs (FBs) with neurological clinical signs (n = 37), group 2 FBs with brachycephalic obstructive airway syndrome (BOAS) (n = 22), group 3 pugs with neurological clinical signs (n = 17), group 4 pugs with BOAS (n = 9) and group 5 normocephalic dogs (n = 37). Cross-sectional area and volume measurements were performed, and tonsillar margination and contour, shape, signal intensity and homogeneity/heterogeneity of the palatine tonsils were evaluated and compared.

RESULTS

Cross-sectional area and volume measurements of the tonsils showed no significant differences between brachycephalic and normocephalic dogs with the exception of the dogs of group 2 (FB BOAS), which showed relatively high volume and large cross-sectional area in comparison to other groups. In 87% of the brachycephalic animals, the tonsils were well defined. A smooth contour was detectable in 91.8% and a rounded shape in 94.7% of brachycephalic dogs. Signal intensity was assessed as hyperintense in relation to the musculature and iso- to hyperintense to the soft palate. Heterogeneous appearance was described in 86.9% of the brachycephalic animals.

CONCLUSIONS

The MRI characteristics of the tonsils of brachycephalic dogs do not differ considerably from those of normocephalic dogs. In FBs with distinct clinical signs of obstructive airway syndrome, increase in cross-sectional area and volume of the tonsils was detected.

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.

Dynamic computed tomography evaluation of the nasopharynx in normal Beagle dogs

Pharyngeal collapsibility has been used as diagnostic criteria in dogs, whereas the normal range and quantitative method have not been studied. Dynamic and static computed tomography (CT) was performed in 23 normal Beagle dogs to quantify the nasopharyngeal collapsibility at different locations. Using dynamic CT, maximum and minimum nasopharyngeal cross-sectional areas (CSAs) were measured at the level of the cranial end of the soft palate, pterygoid hamulus, foramen lacerum, bony labyrinth, and caudal end of the soft palate. The ratio of all maximum and minimum CSA to nasopharyngeal CSA at the level of the caudal hard palate (rCSAmax and rCSAmin) and the nasopharyngeal collapsibility were calculated. The differences of rCSAmax, rCSAmin, and nasopharyngeal collapsibility were analyzed at various locations. The nasopharyngeal collapsibility at the level of foramen lacerum, bony labyrinth, and caudal end of soft palate were higher than the others. At the level of the caudal end of the soft palate, rCSAmin was lower than that of the foramen lacerum and bony labyrinth, whereas rCSAmax at foramen lacerum was higher than that of the caudal end of the soft palate. These results indicated that the nasopharynx at the level of foramen lacerum and caudal end of the soft palate were considered notable locations for evaluating collapsibility. Dynamic CT could show the nasopharyngeal dynamic profile and will be an adequate modality for evaluating nasopharynx. Our results will be helpful for further comparative studies in dogs with and without nasopharyngeal collapse.

Tongue and Upper Airway Dimensions: A Comparative Study between Three Popular Brachycephalic Breeds

Simple Summary

Brachycephalic obstructive airway syndrome is a debilitating disease complex, that affects severely brachycephalic dogs, impairs their quality of life and shortens life expectancy. Macroglossia has been identified as part of the soft tissue conditions that characterize brachycephalic breeds. Despite similar degrees of brachycephalism comparing the common breeds French bulldogs, English bulldogs and pugs, several breed specific characteristics contributing to brachycephalic obstructive airway syndrome have been described in the past. The present study aimed to examine the tongue volume and at three levels cross-sectional areas of the tongue, oropharyngeal airways, soft palate and nasopharyngeal airways in the aforementioned breeds. Assessment of computed tomography scans revealed smaller tongues in pugs compared to French and English bulldogs, with values being close to previously published data in mesaticephalic breeds. Comparing the cross-sectional areas between breeds, several differences were identified, however, calculating the impact of soft tissue on total airways areas uncovered only differences between pugs and French bulldogs at the most caudal location, where the latter breed had a greater ratio, presumably in consequence to a significantly larger oropharyngeal airway area. These findings corroborate the importance of respecting breed specific differences in regard to surgical treatment of brachycephalic obstructive airway syndrome.

Abstract

Relative macroglossia has been identified in brachycephalic compared to mesaticephalic dogs. This study assessed the tongue volume comparing three common brachycephalic breeds, including 30 French bulldogs, 30 pugs, and 15 English bulldogs. Computed tomography scans of intubated dogs with the hard palate suspended were examined for total tongue volume and cross-sectional areas (CSAs) of the tongue, oropharynx, soft palate, and nasopharyngeal airways at three levels: 1, caudal tip of the hard palate; 2, caudal tip of the hamulus; 3 cranial to the basihyoid bone. Tongue volume normalized to bodyweight, was significantly higher in English and French bulldogs than in pugs. Normalized to skull length, CSA of the tongue was smaller in pugs than in French and English bulldogs. At level 3, French bulldogs had larger oropharyngeal CSA than English bulldogs and pugs. Soft palate CSA was the largest in English bulldogs at level 3. At levels 1 and 2, soft palate and nasopharyngeal CSA was the smallest in pugs. At level 3, French bulldogs had higher total airway/soft tissue ratios than pugs. The smaller tongue volume in pugs questions the accuracy of the term macroglossia in this breed and these findings should be considered if surgical correction is sought.

Influence of computed tomographic dimensions of the nasopharynx on middle ear effusion and inflammation in pugs and French bulldogs with brachycephalic airway syndrome

OBJECTIVE

To compare the prevalence of middle ear abnormalities in pugs and in French bulldogs and evaluate the influence of nasopharyngeal dimensions on middle ear effusion.

STUDY DESIGN

Retrospective study.

ANIMALS

Thirty pugs and 30 French bulldogs with brachycephalic airway syndrome and no known history of ear disease.

METHODS

Computed tomographic (CT) studies were reviewed for middle ear effusion, mucosal contrast enhancement, signs of osteitis, and tympanic wall thickness. Soft palate thickness and cross-sectional areas of the nasopharynx at the opening of the auditory tube were measured and normalized to each individual's skull index before statistical comparison between breeds. Statistical dependence of middle ear abnormalities and nasopharyngeal dimensions was assessed by using Spearman's rank correlation tests.

RESULTS

Middle ear effusion was observed in 17 of 30 (56.7%) French bulldogs and five of 30 (16.7%) pugs. Contrast enhancement of the tympanic bulla was noted in 25 of 60 (41.6%) French bulldog ears and three of 60 (5.0%) pug ears. The cross-sectional airway dimensions (difference [Δ] = 0.31 cm² , P < .0001) and soft palate thickness (Δ = 0.44 cm, P < .0001) were reduced in pugs compared with in French bulldogs. Weak correlations were detected between soft palate thickness and nasopharyngeal dimensions and presence of tympanic bulla effusion (r = 0.324 and r = 0.198, respectively) or contrast enhancement (r = 0.270 and r = 0.199, respectively).

CONCLUSION

Middle ear effusion and inflammation were more common in French bulldogs than in pugs and did not seem related to nasopharyngeal dimensions.

CLINICAL SIGNIFICANCE

French bulldogs with brachycephalic airway syndrome seem predisposed to middle ear effusion and inflammation.

Colder Ambient Temperatures Influence Acute Onset Canine Intervertebral Disc Extrusion

Canine intervertebral disc disease is one of the most common neurologic conditions in veterinary medicine but the influence of environmental factors thereon has not been fully investigated. Subjectively, there has been the impression of increased admissions of acute spinal cord injuries due to intervertebral disc extrusion during periods of colder temperatures. In the present retrospective study, the different weather conditions (temperature, precipitation, sunshine, humidity, and atmospheric pressure) during the acute onset of clinical signs and a lag period of 3 days prior to the occurrence of symptoms were analyzed. One-hundred-and-one client owned dogs from the meteorological region of the Lake Geneva were presented to two referral centers during the 6-year (2007–2012) study period. Chondrodystrophic dogs represented 65.3% of our population, with the French Bulldog (19.8%) and Dachshund (17.8%) being the most common breeds. Multivariable logistic regression analysis identified an increased occurrence of intervertebral disc disease during colder temperatures. Our results are congruent with those of human studies which have shown that lower ambient temperatures are associated with more pain and increased risk for muscle injuries. The interplay of endogenous (breed, anatomical characteristics) and exogenous (environmental) factors should be addressed in a larger cohort study.

Canine Brachycephaly: Anatomy, Pathology, Genetics and Welfare

Brachycephalic dog breeds have experienced a marked rise in popularity in recent years. While numerous people clearly desire this phenotype in their pets, many of these dogs unfortunately experience several concomitant sequelae, including major problems with respiration and thermoregulation, as well as gastrointestinal, ophthalmological, dermatological, reproductive and even dental problems. This mini review focuses on the anatomical and pathological changes associated with brachycephalic skull shape, including brachycephalic obstructive airway syndrome and other co-existent disorders. It then details the known genetic contributors to brachycephaly, and concludes with a brief discourse on the welfare of these animals.