Assessment of middle ear disease in the dog: a comparison of diagnostic imaging modalities

Evaluation of canine tympanic membrane integrity using positive contrast computed tomography canalography

Introduction

The assessment of the integrity of the tympanic membrane (TM) can be a diagnostic challenge in patients with otitis externa and/or otitis media (OM) under an otoscopic examination. In computed tomography (CT), the TM is not always visualized. However, a positive contrast canalography using conventional radiography has been previously described to evaluate the TM integrity.

Objective

This single-center study aimed to describe the positive contrast canalography technique in CT and its usefulness in identifying TM integrity in 11 dogs.

Methods

Dogs with clinical signs of ear disease underwent CT canalography following a systematic protocol.

Result

The presence of contrast medium and contrast homogeneity within the tympanic cavity was assessed, confirming TM rupture when contrast medium was present in the tympanic cavity. CT canalography was performed in 16 ears, and in 7 of the 16 ears (44%), there was a contrast in the tympanic cavity, confirming TM rupture (positive CT canalography result). In two of the seven cases (29%), rupture of the TM was identified in both otoscopic and CT canalography. In the remaining five of the seven (71%) positive CT canalography results, tympanic membrane rupture was identified only by CT canalography.

Discussion

In conclusion, a positive contrast CT canalography is a complementary and safe technique to assess TM integrity, with a potentially higher sensitivity than otoscopic examination for the diagnosis of TM rupture in dogs.

Normative wideband acoustic immittance patterns for middle ear evaluation in dogs

The objective of this study was to investigate the clinical use of wideband acoustic immittance (WAI) reflectance for middle ear assessment in dogs. Otoscopy and brainstem auditory evoked response testing was performed on all dogs prior to the WAI assessment. Following calibration, dogs were comfortably restrained while the probe was placed into the ear canal to obtain recordings. Testing was repeated for replicability. Repeatable WAI reflectance patterns were observed in 24 dogs, characterized by low-reflectance resonant peaks at approximately 1500-1800 Hz and 3000-4000 Hz. Observed patterns suggest WAI may be a practical means of assessing middle ear function in dogs.

Effect of empirical versus definitive antimicrobial selection on postoperative complications in dogs and cats undergoing total ear canal ablation with lateral bulla osteotomy: 120 cases (2009-2019)

OBJECTIVE

To evaluate dogs and cats undergoing total ear canal ablation with lateral bulla osteotomy (TECA-LBO), document antimicrobial choices, and determine relationships associated with infection-related and neurologic postoperative complications.

ANIMALS

107 client-owned dogs and 13 client-owned cats that underwent TECA-LBO.

PROCEDURES

A retrospective analysis of medicals records of dogs and cats with TECA-LBO from 2 veterinary hospitals with postoperative data for at least 6 months was performed. All information associated with the TECA-LBO surgery including follow-up was recorded. Logistic regression analyses were performed and corrected using a false discovery rate to identify significance between antimicrobial administration and other perioperative variables and the outcomes of short- and long-term neurologic and infection-related complications, need for revision surgery, and euthanasia due to recurrence of infection-related signs.

RESULTS

Intraoperative cultures were performed in 111 animals, and 95 (85.5%) had bacterial growth, with Staphylococcus spp most commonly isolated. Revision surgeries due to infection-related signs occurred in 13 of 120 (10.8%) patients. If intraoperative bacterial cultures were positive and antimicrobials were administered within 1 month of surgery, patients were 85.8% less likely to exhibit infection-related complications, whereas patients not administered antimicrobials were 10.3 times as likely to require a revision surgery. Longer durations of postoperative antimicrobial administration were associated with revision surgery and euthanasia due to infection-related signs.

CLINICAL RELEVANCE

Administration of systemic antimicrobials within the first postoperative month may be necessary to prevent complications when intraoperative cultures exhibit bacterial growth and plays a role in the successful outcome of TECA-LBO.

Evaluation of Video-Otoscopic, Radiographic and Computed Tomographic Examinations of Cats and Dogs with Ear Diseases

The aim of this study was to evaluate the effectiveness of imaging techniques (video-otoscopy-VO, radiography-RTG, computed tomography-CT) in diagnosing ear diseases in cats and dogs. Seven cats and thirteen dogs diagnosed with ear diseases were used for the research. Clinical examination, VO, RTG and CT were performed. Three (42.9%) unilateral otitis externa (OE), three (42.9%) unilateral otitis media (OM), and one (14.2%) bilateral otitis media (OM) with OE were diagnosed in 7 cats. Five (38.4%) unilateral OE, one (7.7%) unilateral OM, four (30.8%) bilateral OE, and three (23.1%) bilateral OM with OE were diagnosed in 13 dogs. All diagnostic methods were determined to be highly efficient for the specified diagnosis. VO and RTG were confirmed as sufficiently effective for the diagnosis of OE. OE plays a major role in the etiopathogenesis of OM, and for this reason, RTG and CT are required diagnostic methods for this condition.

Aural CT characteristics of American Cocker Spaniels have features of both mesaticephalic and brachycephalic breeds

Otitis externa and otitis media are common in American Cocker Spaniels, however breed-specific aural CT descriptions are currently lacking. This prospective and retrospective, observational, analytical study aimed to describe quantitative CT characteristics of the horizontal ear canal and the tympanic bulla in American Cocker Spaniels versus similar-sized mesaticephalic dogs. We prospectively performed clinical examinations and aural CT scanning for 38 American Cocker Spaniels. Computed tomographic transverse area of the osseous horizontal ear canal (TA1), transverse area of the widest air-filled part of the cartilaginous horizontal ear canal (TA2), tympanic bulla volume, and tympanic bulla wall thickness were measured. The TA1 and TA2 measurements were compared with those of 23 retrospectively recruited, similar-sized mesaticephalic dogs that had undergone CT-scanning of the head for non-ear-related reasons. The TA1 and TA2 did not differ for healthy American Cocker Spaniels and mesaticephalic dogs. Severely affected American Cocker Spaniels had significantly smaller TA2 (P < .001). The intraclass correlation coefficient for intraobserver and interobserver repeatability was 0.972 and 0.983 for TA1 and 0.994 and 0.998 for TA2, respectively. Variation between individuals was subjectively noted in healthy and affected American Cocker Spaniels, but mean tympanic bulla volume was slightly smaller in relation to body weight, and the tympanic bulla wall was thicker than in previous reports for mesaticephalic dogs. The tympanic bulla wall appeared thicker rostro-ventrally than caudo-ventrally in 44% of the dogs. Our results imply that a relatively thick tympanic bulla wall may be a normal CT variation and should be interpreted cautiously in this breed.

Validation of an ultrasound imaging technique of the tympanic bullae for the diagnosis of otitis media in calves

Background

Otitis media is a common disease in calves that can be subclinical, making antemortem on‐farm diagnosis challenging.

Objectives

To evaluate the sensitivity and specificity of ultrasonography of tympanic bullae for the diagnosis of clinical and subclinical otitis media and to evaluate the reproducibility of the technique.

Animals

Forty calves 19–50 days of age were selected from a veal calf farm.

Methods

Prospective study. Ultrasonography was first performed on the farm by ultrasonographer A (US A). Ultrasonography was repeated by ultrasonographer A (US A') and another ultrasonographer (US B) at the Centre Hospitalier Universitaire Vétérinaire. Images were later reread by both examiners and a diagnosis was recorded. The calves were euthanized and submitted for necropsy, and histopathologic diagnosis was used as the gold standard.

Results

Forty‐five bullae were affected by otitis media and 35 bullae were normal. Sensitivity and specificity of the ultrasound technique ranged from 32 to 63% and 84 to 100%, respectively, depending on the examiner and classification of suspicious ultrasonography results. Kappa analysis to evaluate interobserver agreement between A' and B yielded a к value of 0.53. Agreement within the same examiner (A versus A') yielded a к value of 0.48, and real‐time ultrasound versus rereading of recorded images for A' and B yielded к values of 0.58 and 0.75, respectively.

Conclusions

Sensitivity and specificity of the ultrasound imaging technique are, respectively, low and high for diagnosis of clinical and subclinical otitis media in calves, with moderate reproducibility.

Management of complications associated with total ear canal ablation and bulla osteotomy in dogs and cats

Total ear canal ablation combined with bulla osteotomy is a salvage procedure recommended primarily for end-stage inflammatory ear canal disease but also for neoplasia and severe traumatic injuries. Due to the complexity of the procedure and the poor exposure associated with the surgical approach, there is significant risk for a variety of complications. This review discusses intraoperative, early postoperative, and late postoperative complications reported in large retrospective studies, the causes for these complications, and recommendations about how to prevent them.