Soft palate hypoplasia and concurrent middle ear pathology in six dogs

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.

Patulous Eustachian tube and palatine defect in a Dachshund with chronic unilateral otitis externa and otitis media

BACKGROUND

Patulous Eustachian tube (pET) is a rare dysfunction of the Eustachian tube described in humans. It is characterized by failure of the ET to close, resulting in unrestricted passage of air, sound and material between the nasopharynx and the middle ear.

OBJECTIVE

To report a case of pET associated with otitis in a dog.

ANIMAL

A 6-year old-female spayed Dachshund dog.

METHODS AND MATERIALS

Otoscopic examination, cytological evaluation, culture and susceptibility, computerized tomography (CT), video-otoscopic flushing and surgery.

RESULTS

Left ear otoscopic examination revealed erythema, purulent frothy discharge, ceruminous gland hyperplasia, stenosis and a partial tear of the tympanum. Cytological evaluation from the left external canal showed neutrophils, macrophages, rods and cocci. Aerobic culture showed predominantly multidrug-resistant Pseudomonas aeruginosa. The CT findings of the left ear included chronic changes in the external canal, marked lysis of the tympanic bulla and marked dilation of the ET. During video-otoscope flushing, saline drained through the mouth. Bilateral incomplete hypoplasia of the soft palate was noted. Total ear canal ablation and bulla osteotomy with ET dissection were curative. Histopathological findings were compatible with chronic otitis externa (OE) and media.

CONCLUSION AND CLINICAL IMPORTANCE

To the best of the authors' knowledge, this is the first case of pET described in animals. The ET dysfunction and palatine defect were likely the cause of the otitis in this dog. Clinicians should investigate pET in animals with signs of OE characterized by frothy liquid and food fragments in the ear canal in addition to sneezing after drinking water.

Facial changes related to brachycephaly in Cavalier King Charles Spaniels with Chiari-like malformation associated pain and secondary syringomyelia

BACKGROUND

Recent studies including an innovative machine learning technique indicated Chiari-like malformation (CM) is influenced by brachycephalic features.

OBJECTIVES

Morphometric analysis of facial anatomy and dysmorphia in CM-associated pain (CM-P) and syringomyelia (SM) in the Cavalier King Charles Spaniel (CKCS).

ANIMALS

Sixty-six client-owned CKCS.

METHODS

Retrospective study of anonymized T2W sagittal magnetic resonance imaging of 3 clinical groups: (1) 11 without central canal dilation (ccd) or SM (CM-N), (2) 15 with CM-P with no SM or <2 mm ccd (CM-P), and (3) 40 with syrinx width ≥4 mm (SM-S). Morphometric analysis assessed rostral skull flattening and position of the hard and soft palate relative to the cranial base in each clinical group and compared CKCS with and without SM-S.

RESULTS

Sixteen of 28 measured variables were associated to SM-S compared to CM-N and CM-P. Of these 6 were common to both groups. Predictive variables determined by discriminant analysis were (1) the ratio of cranial height with cranial length (P < .001 between SM-S and CM-N) and (2) the distance between the cerebrum and the frontal bone (P < .001 between SM-S and CM-P). CM-P had the lowest mean height of the maxillary area.

CONCLUSIONS AND CLINICAL IMPORTANCE

CKCS with CM-P and SM-S have cranial brachycephaly with osseous insufficiency in the skull with rostral flattening and increased proximity of the hard and soft palate to the cranial base. Changes are greatest with CM-P. These findings have relevance for understanding disease pathogenesis and for selection of head conformation for breeding purposes.

Incidence patterns of orofacial clefts in purebred dogs

Cleft lip (CL), cleft palate (CP) and cleft lip and palate (CLP) are the most common types of orofacial clefts in dogs. Orofacial clefts in dogs are clinically relevant because of the associated morbidity and high newborn mortality rate and are of interest as comparative models of disease. However, the incidence of CL, CP and CLP has not been investigated in purebred dogs, and the financial impact on breeders is unknown. The aims of this study were to document the incidence patterns of CL, CP and CLP in different breeds of dogs, determine whether defect phenotype is associated with skull type, genetic cluster and geographic location, and estimate the financial impact in breeding programs in the United States by means of an anonymous online survey. A total of 228 orofacial clefts were reported among 7,429 puppies whelped in the 12 preceding months. Breeds in the mastiff/terrier genetic cluster and brachycephalic breeds were predisposed to orofacial clefts. Certain breeds in the ancient genetic cluster were at increased odds of orofacial clefts. Male purebred dogs were at increased odds of CPs. Results confirm that brachycephalic breeds are overrepresented among cases of orofacial clefts. Furthermore, geographic region appeared to be a relevant risk factor and orofacial clefts represented a considerable financial loss to breeders. Improved understanding of the epidemiology of orofacial clefts (frequency, causes, predictors and risk factors) may help in identifying ways to minimize their occurrence. Information gained may potentially help veterinarians and researchers to diagnose, treat and prevent orofacial clefts.

Use of a split-thickness soft palate hinged flap and bilateral buccal mucosal rotation flaps for one-stage repair of a bilateral hypoplastic soft palate in a dog

CASE DESCRIPTION

A 14-week-old 8.5-kg (18.7-lb) sexually intact female Springer Spaniel was evaluated because of chronic rhinitis with bilateral mucopurulent nasal discharge. The dog had a history since birth of sneezing and oronasal reflux of food and liquid.

CLINICAL FINDINGS

Oral examination under anesthesia revealed a short, incompletely formed soft palate with bilateral clefts. A pseudouvula was not a prominent feature of the condition in this dog.

TREATMENT AND OUTCOME

The dog underwent 1-stage reconstruction of the soft palate by means of a split-thickness soft palate hinged flap and bilateral buccal mucosal rotation flaps. Long-term follow-up obtained 3 years after surgery revealed the dog to be in good general health, with resolution of oronasal reflux; however, occasional episodes of mild sneezing and nasal discharge persisted. Oral examination under sedation revealed attenuation of the bilateral clefts; however, a normal soft palate length was not achieved.

CLINICAL RELEVANCE

Compared with previously described techniques, this technique offered the possibility of 1-stage reconstruction of the soft palate in dogs, rather than having 2 staged procedures performed, and a robust tissue combination that was expected to be less prone to trauma. This technique may be particularly suitable for affected dogs where a pseudouvula is not a prominent feature and appears to be applicable to a variety of skull morphologies. Owners should be made aware that the absence of normal palatine muscle within the reconstructed palate may affect function, but even where normal function is not regained, a good quality of life with minimal clinical signs may be achieved.

Prevalence of ear disease in dogs undergoing multidetector thin-slice computed tomography of the head

Previous reports describing the prevalence of ear diseases in dogs have primarily been based on dogs presenting with clinical signs of disease. The prevalence of subclinical ear disease remains unknown. The purpose of this cross-sectional retrospective study was to describe the prevalence of lesions consistent with middle and external ear disease in dogs presented for multidetector computed tomography (CT) of the head and/or cranial cervical spine at our hospital during the period of July 2011 and August 2013. For each included dog, data recorded were signalment, CT findings, diagnosis, and treatment. A total of 199 dogs met inclusion criteria. Nineteen dogs (9.5%) were referred for evaluation of suspected ear disease and 27 dogs (13.5%) had histories or physical examination findings consistent with otitis externa. A total of 163 dogs (81.9%) had CT lesions consistent with external ear disease (i.e. ear canal mineralization, external canal thickening, and/or narrowing of the external canal). Thirty-nine dogs (19.5%) had CT lesions consistent with middle ear disease (i.e. soft tissue attenuating/fluid material in the tympanic bullae, bulla wall thickening or lysis, and/or periosteal proliferation of the temporal bone). Findings from this study indicated that the prevalence of external and middle ear disease in dogs could be higher than that previously reported.

Craniomaxillofacial abnormalities in dogs with congenital palatal defects: computed tomographic findings

OBJECTIVE

To evaluate craniomaxillofacial abnormalities in dogs with congenital palatal defects.

STUDY DESIGN

Retrospective computed tomography (CT) study.

ANIMALS

Dogs with congenital palatal defects (n = 9).

METHODS

Medical records and CT reports (1995-2012) were searched for dogs with a diagnosis of cleft palate that had a CT study. Data retrieved were: breed, age, sex, weight, physical examination, and laboratory findings, number of previous palate surgeries, and oral/dental examination findings with the diagnosis of the cleft for each dog. CT studies of the head were reviewed on a structure-by-structure basis.

RESULTS

Tympanic bullae were most commonly found to be abnormal (8 dogs), followed by nasal turbinates (6), nasal septum, vomer, cribriform plate (4), frontal sinuses, and lateral ventricles (3). Other abnormalities were related to occlusion, teeth, incisive bones, maxillary bones, mandibles, hyoid apparatus, cranial bones, and nasopharynx. The soft tissue defect of the cleft was always smaller than the bony defect.

CONCLUSIONS

Craniomaxillofacial abnormalities in dogs with congenital palatal defects are common and some of these may negatively affect the quality of life. Importantly for surgical planning, the soft tissue component of the cleft may underestimate the extent of the bony defect, especially in failed repairs.

The association of middle ear effusion with trigeminal nerve mass lesions in dogs

The trigeminal nerve is involved in the opening of the pharyngeal orifice of the Eustachian tube by operating the tensor veli palatini muscle. The hypothesis was investigated that middle ear effusion occurs in a more severe disease phenotype of canine trigeminal nerve mass lesions compared with dogs without middle ear effusion. Three observers reviewed canine MRIs with an MRI-diagnosis of trigeminal nerve mass lesion from three institutions. Various parameters describing the musculature innervated by the trigeminal nerve were scored and compared between dogs with and without middle ear effusion. Nineteen dogs met the inclusion criteria. Ipsilateral middle ear effusion was observed in 63 per cent (95% CI 48.4 per cent to 77.6 per cent) of the dogs. The size of the trigeminal nerve mass lesions was positively correlated with the severity of masticatory muscle mass loss (Spearman r=0.5, P=0.03). Dogs with middle ear effusion had a significantly increased generalised masticatory muscle mass loss (P=0.02) or tensor veli palatini muscle loss score (P=0.03) compared with those without. Larger trigeminal nerve mass lesions were associated with a greater degree of masticatory muscle mass loss. Masticatory muscle mass and, importantly, tensor veli palatini muscle mass was more severely affected in dogs with middle ear effusion suggesting an associated Eustachian tube dysfunction.

Prevalence of effusion in the tympanic cavity in dogs with dysfunction of the trigeminal nerve: 18 cases (2004-2013)

BACKGROUND

Animals with disorders involving the trigeminal nerve or its nuclei in the brainstem can have effusion in the tympanic cavity ipsilateral to the side of the neurological deficits. The tensor veli palatini muscle (TVP), innervated by the mandibular branch of the trigeminal nerve, opens the pharyngeal orifice of the auditory tube. With denervation of the TVP, dysfunction of the auditory tube may occur, which could lead to effusion.

HYPOTHESIS/OBJECTIVES

To determine the prevalence of effusion in the tympanic cavity in dogs with disorders involving the trigeminal nerve.

ANIMALS

Eighteen client-owned dogs were evaluated retrospectively.

METHODS

Retrospective study.

RESULTS

Diagnostic imaging databases were searched for dogs having undergone magnetic resonance imaging (MRI) evaluation for signs referable to dysfunction of the trigeminal nerve. Signalment and neurological examination findings were recorded. The MRI study was evaluated for the presence or absence of effusion. MRI characteristics of the affected trigeminal nerve and the muscles of mastication were recorded. Based on the location of the trigeminal nerve lesion, dogs were divided into three categories: brainstem, trigeminal canal, or extracranial. Eighteen dogs met the inclusion criteria. Six of 18 dogs (33%) had effusion in the tympanic cavity ipsilateral to the affected trigeminal nerve.

CONCLUSION AND CLINICAL IMPORTANCE

A substantial proportion of dogs with a lesion affecting the trigeminal nerve had effusion in the tympanic cavity. This finding likely represents denervation of the TVP muscle, which may have led to dysfunction of the auditory tube.