Passive drainage versus primary closure after total ear canal ablation-lateral bulla osteotomy in dogs: 59 dogs (1985-1995)

Influence of extreme brachycephalic conformation on perioperative complications associated with total ear canal ablation and lateral bulla osteotomy in 242 dogs (2010-2020)

OBJECTIVE

To determine the influence of extreme brachycephalic conformation on presenting signs, imaging findings, intraoperative and perioperative complications following total ear canal ablation and lateral bulla osteotomy (TECA-LBO).

STUDY DESIGN

Cross-sectional retrospective study.

ANIMALS

A total of 306 (n = 242 dogs) TECA-LBOs (extreme brachycephalic breeds [EBB] = 81, other breeds [OB] = 225).

METHODS

Medical records of patients undergoing TECA-LBO at a single referral institution (2010-2022) were evaluated.

RESULTS

Extreme brachycephalic breeds most commonly presented acutely, at a younger age with oto-neurological signs (46/81, 56.8%). Chronic otitis externa without neurological signs (171/225, 76.0%) was most common in OBs. Extreme brachycephalic breeds preoperatively presented more frequently with facial nerve paresis (p = .001), vestibular syndrome (p = .001), and Horner's syndrome (p = .002) compared to OBs. On diagnostic imaging, bilateral changes (p = .038), aural masses (p = .045), para-aural abscesses (p = .011), otitis interna (p = .001), and brainstem changes (p = .001) were more common in EBBs. The apparent difference in intraoperative complication rate between EBBs (9/81, 11.1%) and OBs (12/225, 5.3%) did not reach statistical significance (p = .078). Perioperative complications occurred in 85/306 (27.8%) of TECA-LBOs with no difference in perioperative complication rate between EBBs (19/81, 23.5%) and OBs (66/225, 29.3%) (p = .586).

CONCLUSION

Extreme brachycephalic breeds are more likely to present for TECA-LBO acutely, with neurological signs and more advanced diagnostic imaging abnormalities. Intra- and perioperative complication rates did not differ between EBBs and OBs.

CLINICAL SIGNIFICANCE

Despite being subjectively more technically challenging, TECA-LBO did not result in more surgical complications in EBBs. Reported data are useful for effectively informing clients of the specific risks of TECA-LBO surgery.

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.

Experience level as a predictor of entry into the hypotympanum during feline total ear canal ablation and lateral bulla osteotomy

OBJECTIVES

The study hypotheses were as follows: (1) owing to the unique anatomy of the feline middle ear, the hypotympanum would be entered in less than 100% of cats during total ear canal ablation and lateral bulla osteotomies (TECA-LBOs); and (2) incomplete penetration of the septum and subsequent failure to enter the hypotympanum is more likely to occur in surgeries performed by a novice surgeon when compared with an experienced surgeon and may be under-recognized.

METHODS

Head CT was performed in 12 feline cadavers to confirm absence of gross ear disease. A novice surgeon and an experienced surgeon were randomly assigned to perform TECA-LBO on the left or right ear. Surgeons were blinded to each other's surgical technique. CT of cadavers was performed after the procedure. Successful penetration of the septum, entry into the hypotympanic cavity and amount of bone removed in bulla osteotomy, quantified via CT, were compared between the novice surgeon and experienced surgeon.

RESULTS

The novice surgeon entered the hypotympanum in 3/12 (25%) procedures, compared with 9/12 (75%) procedures performed by the experienced surgeon. The experienced surgeon performed a larger osteotomy than the novice surgeon (3301 mm vs 1376 mm, P<0.0023). Regardless of surgeon experience, more bone was removed in surgeries in which the hypotympanum was entered.

CONCLUSIONS AND RELEVANCE

Our results underscore the need for familiarity with feline middle ear anatomy when performing TECA-LBOs. Postoperative CT is recommended for novice surgeons to confirm entry into the hypotympanum.

Traumatic Tympanic Bulla Fracture in a Cat With Severe Head Trauma

A nine-year-old male European shorthair cat was referred to our practice with severe head trauma after suffering a road traffic accident (RTA). The patient presented marked facial swelling and multiple skin wounds and bruising, inspiratory dyspnea, palpable mandibular and maxillary fractures, serosanguinolent oronasal discharge and right eye exophthalmos and buphthalmos with loss of menace and pupillary reflex. After stabilizing the patient, a CT scan was performed under general anesthesia and an oesophagostomy tube was placed. The scan revealed the presence of multiple right tympanic bulla fractures. Multiple mandibular, maxillary, and palatine fractures were also present. The cat underwent surgery. Mandibular symphyseal separation and maxillary fractures were stabilized using intraoral cerclage wire fixation reinforced with composite and the right eye was enucleated. The rest of the fractures were treated conservatively. A CT scan 4 months after the trauma was also performed. At this point, the maxillofacial fractures were healing properly, and a bone callus demonstrating fusion of fragments of the right tympanic bulla was evident. There was absence of abnormal content inside the right tympanic bulla. The patient recovered uneventfully with no neurological deficits. To the author's knowledge this is the first case reporting a traumatic tympanic bulla fracture in the cat with case follow up, and the first case reported using CT as diagnostic imaging test.

Otoscopic evaluation of epithelial remnants in the tympanic cavity after total ear canal ablation and lateral bulla osteotomy

OBJECTIVE

To determine the ability to detect the presence of epithelial remnants after total ear canal ablation (TECA) and lateral bulla osteotomy (LBO) with endoscopy and to identify the most common locations of epithelial remnants after tympanic curettage.

STUDY DESIGN

Experimental study.

ANIMALS

Five fresh canine cadavers with no gross evidence of middle ear disease.

METHODS

Ten TECA-LBO were performed by four surgeons. After tympanic curettage, a 1.9-mm rigid 30° endoscope was inserted into the rostral, caudal, dorsal, ventral, and medial sections of the tympanic cavity. Three observers evaluated otoscopic images for epithelial remnants in each compartment. The median distribution of epithelial remnants was calculated for each section of the tympanic cavity with a three-dimensional tympanic cavity model.

RESULTS

Epithelial remnants were identified in at least one of the five areas of the tympanic cavity after each TECA-LBO. The rostral section contained the most epithelial remnants (35.6%), while the medial section contained the least amount (1.8%).

CONCLUSION

Use of a 1.9-mm rigid endoscope was an effective method to evaluate all sections of the tympanic cavity after curettage in TECA-LBO. Epithelial remnants were consistently found after TECA-LBO, especially in the rostral compartment.

CLINICAL SIGNIFICANCE

Intraoperative endoscopy should be considered to improve removal of epithelium after initial TECA-LBO or revision surgeries.

Traumatic tympanic bulla fracture

A Pekingese dog was presented for evaluation of head trauma with ventral head and neck swelling, puncture wounds, palpable mandibular fractures, and loss of menace, severe miosis, and loss of palpebral reflex of the right eye. Computed tomography confirmed multiple mandibular and zygomatic fractures, a right ear canal avulsion, and a complete right tympanic bulla fracture with ventral displacement. The tympanic bulla fracture was managed conservatively. Topical lubrication and antibiotic ointment was prescribed for the right eye. A subtotal hemimandibulectomy was performed to address the mandibular fractures. A temporary oesophagostomy feeding tube was placed. No short-term complications developed as a result of the fractured bulla and avulsed ear canal being left in situ, and no complications were reported 18 months after the injury. To the authors' knowledge this is the first report of a traumatic tympanic bulla fracture in the dog.

Postoperative complications following TECA-LBO in the dog and cat

The medical records for 133 total ear canal ablations combined with lateral bulla osteotomies (TECA-LBOs) performed on 82 dogs (121 ears) and 11 cats (12 ears) between 2004 and 2010 were reviewed to determine if the duration of preoperative clinical signs was associated with the incidence of postoperative facial nerve injury and Horner's syndrome. Other perioperative complications, such as a head tilt, nystagmus, incisional drainage, draining tracts, hearing loss, as well as bacterial culture results, were noted. Postoperative facial nerve paresis occurred in 36 of 133 ears (27.1%), and paralysis occurred in 29 of 133 ears (21.8%), with no significant difference between species. Thus, postoperative facial nerve deficits occurred in 48.9% of ears. The median duration of clinically evident temporary facial nerve deficits was 2 wk for dogs and 4 wk for cats. Dogs had a significantly longer duration of preoperative clinical signs and were less likely than cats to have a mass in the ear canal. Dogs were less likely to have residual (> 1 yr) postoperative facial nerve deficits. The incidence of postoperative Horner's syndrome was significantly higher in cats than dogs. The duration of preoperative clinical signs of ear disease was not associated with postoperative facial nerve deficits.

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.

Multiple follicular cysts of the ear canal in a dog

An 11-year-old, 18-kg, neutered male standard schnauzer was presented for evaluation of recurrent otitis externa with para-aural swelling and fistulation of the right external ear canal of 6 months' duration. Otoscopic examination was impossible because of the severe stenosis of the ear canal. Right para-aural ultrasound examination and ultrasound-guided fine-needle aspiration of a mass-like lesion were performed. Cytology was suggestive of a follicular cyst. Magnetic resonance imaging revealed severe ear canal stenosis with a heterogeneous mass in the horizontal portion of the ear canal and associated otitis media. Total ear canal ablation with lateral bulla osteotomy was performed. Histopathological diagnosis was chronic otitis externa associated with multiple follicular cysts confined to the ear canal. Surgical treatment proved curative. This is the first report of multiple follicular cysts originating from the ear canal in a dog.

Evaluation of a local anesthetic delivery system for the postoperative analgesic management of canine total ear canal ablation--a randomized, controlled, double-blinded study

OBJECTIVE

To determine if a constant rate local anesthetic delivery system is more effective than continuous intravenous (IV) morphine infusion for postoperative analgesia.

ANIMALS

Twenty client-owned dogs undergoing total ear canal ablation.

METHODS

Dogs were randomly assigned to the lidocaine group (LID) or the morphine group (MOR). The LID group received a constant rate infusion of lidocaine locally and a continuous IV infusion of saline, while the MOR group received a constant rate infusion of saline locally and a continuous IV infusion of morphine. The primary investigator evaluated each patient and determined a hospital behavior score, anesthesia recovery score, preoperative pain score, and serial postoperative pain and sedation scores over 38 hours. Pain and sedation observations were videotaped and scored by three additional evaluators. Evaluators were blinded to treatment assignments.

RESULTS

There were no significant differences in age, weight, hospital behavior scores or anesthesia recovery scores. The primary investigator's pain scores were not significantly different, but sedation scores were significantly lower for the LID group. Sedation and pain scores by the video evaluators were not significantly different between groups. Kappa agreement between observers was poor, but better agreement was noted between sedation scores than pain scores. Drug-related complications were significantly lower in the LID group (n = 0) compared with the MOR group (n = 5). Wound complications were not significantly different (LID = 4, MOR = 4). Intravenous delivery complications occurred in 12 (60%) patients. Local delivery complications occurred in five (25%) dogs. Delivery complications were not significantly different between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Continuous incisional lidocaine delivery was an equipotent and viable method of providing postoperative analgesia compared with IV morphine. Lidocaine delivery resulted in a trend toward lower pain scores, significantly lower sedation scores, and no dogs requiring analgesic rescue. Wound complications secondary to local infusion were minor and self-limiting. Drug-related complications occurred only in the MOR group.

MAGNETIC RESONANCE IMAGING OF THE INTRATEMPORAL FACIAL NERVE IN IDIOPATHIC FACIAL PARALYSIS IN THE DOG

The most common cause of peripheral facial nerve paralysis in dogs, in the absence of otitis media, is thought to be idiopathic. Gadolinium-enhanced (Gd) magnetic resonance (MR) imaging has been used to study peripheral facial weakness in humans with a wide variety of disorders, including Bell's palsy, the clinical equivalent of idiopathic facial nerve paralysis in dogs. Gd-MR imaging may be useful to demonstrate abnormal enhancement of the intratemporal facial nerve. The aim of this study was to define the role of the Gd-MR imaging in dogs with idiopathic facial nerve paralysis, with regard to pattern of enhancement, and to search for prognostic information. Six dogs with peripheral facial nerve paralysis, followed between 2003 and 2005, were studied. Physical and neurologic examinations, as well as clinical tests, were performed, including routine hematology, serum biochemistry, thyroid screening, cerebrospinal fluid analysis, and MR imaging. The time interval between the onset of the clinical signs, the progress of the disease, and the final recovery was noted in each dog. The following four intratemporal segments of the facial nerve were analyzed: internal acoustic meatus, labyrinthine segment/geniculate ganglion, tympanic segment, and mastoid segment. Along its length, contrast enhancement was found in four dogs. In this group, contrast enhancement of the facial nerve was found in all segments of two dogs, in three segments of one dog, and in one segment of the other dog. In the four dogs with enhancement, one recovered completely in 8 weeks and three have not recovered completely. The two dogs without evidence of enhancement recovered completely in an average time of 4 weeks.

Effect of tympanic cavity evacuation and flushing on microbial isolates during total ear canal ablation with lateral bulla osteotomy in dogs

OBJECTIVE

To evaluate differences in bacterial numbers, identity, and susceptibility in samples obtained from the tympanic cavity on entry (preflush) and after evacuation and lavage (postflush) and assess perioperative and empiric antimicrobial selection in dogs that underwent total ear canal ablation (TECA) with lateral bulla osteotomy (LBO) or reoperation LBO.

DESIGN

Prospective clinical study.

ANIMALS

34 dogs.

PROCEDURE

TECA with LBO or reoperation LBO was performed on 47 ears. Pre- and postflush aerobic and anaerobic samples were obtained from the tympanic cavity. Isolates and antimicrobial susceptibility patterns were compared.

RESULTS

Different isolates (31/44 [70%] ears) and susceptibility patterns of isolate pairs (6/44 [14%] ears) were detected in pre- and postflush samples from 84% of ears. Evacuation and lavage of the tympanic cavity decreased the number of bacterial isolates by 33%. In 26% of ears, bacteria were isolated from post-flush samples but not preflush samples. Only 26% of isolates tested were susceptible to cefazolin. At least 1 isolate from 53% of dogs that received empirically chosen antimicrobials postoperatively was resistant to the selected drugs. Anaerobic bacteria were recovered from 6 ears.

CONCLUSIONS AND CLINICAL RELEVANCE

Accurate microbiologic assessment of the tympanic cavity should be the basis for selection of antimicrobials in dogs undergoing TECA with LBO. Bacteria remain in the tympanic cavity after evacuation and lavage. Cefazolin was a poor choice for dogs that underwent TECA with LBO, as judged on the basis of culture and susceptibility testing results.

Surgery of the ear and pinna

There are several disease processes of the ear and pinna that warrant surgical intervention. This article reviews surgical anatomy and common surgical procedures of the ear and pinna, including aural hematomas, lateral wall resection, vertical ear canal resection, total ear canal ablation and lateral bulla osteotomy, partial pinna resection, and feline inflammatory polyps. The clinical signs, diagnosis, and surgical treatment along with potential complications for each disease process are discussed.

Inflammatory polyps and aural neoplasia

Although aural neoplasia is a relatively uncommon entity in companion animals, it remains a group of heterogeneous conditions that can have a significant negative impact on quality and duration of life of dogs and cats. Chronic ear disease that responds poorly or partially to empiric therapy should raise the suspicion that an underlying condition, such as neoplasia, may be the perpetrator of inflammation. Early diagnosis followed by appropriate therapy improves the likelihood of disease control and prolonged survival.

Surgical management of 43 cases of chronic otitis externa in the dog

Over a seven-year period, chronic otitis externa was surgically managed in 43 dogs at the University Veterinary Hospital of University College Dublin. Lateral ear canal resection (LECR) was undertaken in nine of the 43 dogs: results were unsatisfactory, with a failure of the surgery in five of eight dogs and one dog lost to follow-up. Once end-stage otitis externa, with or without otitis media, is diagnosed, total ear canal ablation and lateral bulla osteotomy (TECA/LBO) is the best treatment option. In this series, 37 of 43 dogs underwent TECA/LBO and of the 29 dogs for which follow-up results were obtained 27 (93%) had an excellent or improved outcome to surgery. Complications following all procedures were most common in cases with a concurrent dermatopathy; therefore, definitive diagnosis and medical treatment for skin and ear disease is essential.

Nasopharyngeal polyps in cats

Nasopharyngeal polyps are non-neoplastic, inflammatory growths that arise from the middle ear or the eustachian tube and extend into the pharynx. The exact etiology of nasopharyngeal polyps is unclear; proposed etiologies include a response to chronic upper respiratory tract infection, chronic otitis media, ascending infection from the nasopharynx, or a congenital origin. Clinical signs usually relate to obstruction of the nasopharynx, with Horner's syndrome and head tilt being consistent with otitis media and otitis interna, respectively. Diagnostic tools include digital or visual examination above the soft palate, flexible fiberoptic caudal rhinoscopy, radiography, computed tomography, and magnetic resonance imaging. Ventral bulla osteotomy combined with traction removal of the polyp is the recommended treatment, although traction only followed by prednisolone therapy can be considered in some cases, especially when there is no evidence of otitis media.

Feline nasopharyngeal polyps

In summary, an ideal diagnostic plan for cats with suspected FNPs should include a thorough anesthetized oropharyngeal examination, otoscopic examination, and imaging studies, which may consist of a bulla radiographic series or specialized imaging studies such as CT or MR scans. In general, if signs indicative of otitis media are present, ventral bulla osteotomy should be advised. As a result of the distinct appearance of FNPs, a preoperative biopsy is not indicated in all instances but should be considered if there are atypical features to the history or presentation. Traction-avulsion of polyps through the external ear canal or auditory tube from the oropharynx may have a lower success rate than traction-avulsion combined with ventral bulla osteotomy. If the veterinarian opts to treat FNPs by traction-avulsion alone as a result of financial constraints imposed by the client, the client should be strongly cautioned regarding potential recurrence. Postoperative complications are possible with any treatment option, but neurologic impairment, including Horner's syndrome, facial neuropathy, and hypoglossal neuropathy, is significantly more likely after surgical intervention by ventral bulla osteotomy than after traction-avulsion alone. A high percentage of these complications are self-limiting. In all instances, appropriate culture and sensitivity and biopsy specimens should be collected so as to enable provision of appropriate postoperative care. Antibiotic therapy should be provided based on culture and sensitivity test results. The use of postoperative steroids to prevent recurrence is controversial.