Effect of Plate Inclination and Osteotomy Positioning on Rock-back following Tibial Plateau Levelling Osteotomy in Dogs.

OBJECTIVE: Rock-back is a reported complication following tibial plateau levelling osteotomy (TPLO), whereby tibial plateau angle (TPA) increases postoperatively. The mechanism of rock-back is not fully understood, although a recent ex vivo investigation demonstrated that osteotomy exit cut angle (ECA) and inclination of the plate in the sagittal plane might be risk factors. The purpose of this study was to explore these relationships in a clinical dog population. We hypothesized that dogs with rock-back would have a higher degree of plate inclination and downward ECA compared with those without rock-back. MATERIALS AND METHODS: Medical records and radiographs of dogs that underwent TPLO between January 2021 and January 2022 were retrospectively reviewed. TPA was recorded preoperatively, postoperatively, and at follow-up. Plate inclination, ECA, and descriptive data were collected. Observers measuring TPA were blinded to other variables. Rock-back was defined as a change in TPA ≥ 2. RESULTS: Ninety-five TPLO procedures met the inclusion criteria (n = 87 dogs). Rock-back was identified in 21% of TPLOs (n = 20/95). The mean increase in TPA in the rock-back group was 3.2 ± 2.6. Plate inclination and ECA were not correlated with the presence of rock-back. Descriptive variables did not have a significant correlation with rock-back. CONCLUSION: Plate inclination and ECA did not have a relationship with rock-back when defined as a postoperative TPA change ≥2 degrees, in this clinical retrospective study.

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.

Assessment of normal radial joint orientation angles in nonchondrodystrophic small-breed dogs.

OBJECTIVE: To establish reference intervals for radial joint orientation angles in the frontal and sagittal planes in small-breed dogs and to compare them to those previously reported for medium- and large-breed dogs. ANIMALS: Antebrachii of 30 skeletally mature, nonchondrodystrophic small-breed dogs were evaluated radiographically. PROCEDURES: Orthogonal radiographs were retrospectively assessed to determine the anatomic medial proximal radial angle, anatomic lateral distal radial angle, anatomic cranial proximal radial angle (aCrPRA), and anatomic caudal distal radial angle (aCdDRA). The frontal plane angle, θ angle, and procurvatum were also calculated. The radial joint orientation angles determined were compared to those previously reported for medium- and large-breed dogs via a 1-sample t test. RESULTS: Mean and SD values for anatomic medial proximal radial angle, anatomic lateral distal radial angle, aCrPRA, and aCdDRA were 80.86 ± 2.86°, 85.60 ± 1.74°, 87.99 ± 2.79°, and 83.08 ± 3.14°, respectively. The mean and SDs for frontal plane angle, θ angle, and procurvatum were 4.75 ± 2.46°, 11.88 ± 1.76°, and 16.79 ± 4.13°, respectively. aCrPRA and aCdDRA were significantly different when compared to previously reported radial joint angles for medium- and large-breed dogs. CLINICAL RELEVANCE: Reference intervals for small-breed dog radial joint orientation angles were reported. Significant differences were identified for some joint orientation angles when compared to medium- and large-breed dogs. This small-breed reference interval reported can be utilized in planning of radial angular limb deformity corrective surgery, particularly when dogs are bilaterally affected.

Prognostic indicators of short-term outcome in dogs undergoing surgery for brachycephalic obstructive airway syndrome.

BACKGROUND: The aims of this study were to assess the impact of epidemiological variables, severity of presurgical respiratory signs, diagnostic findings from pharyngeal and laryngeal examination using a new grading scheme and CT scan images, on postsurgical outcome in dogs undergoing surgery for brachycephalic obstruction airway syndrome (BOAS). METHODS: An owner-based questionnaire was used to grade dogs based on their respiratory signs before surgery and at least six weeks after surgery. Epidemiological data and results from presurgical pharyngeal and laryngeal examination and CT scan findings for 75 dogs undergoing airway surgery were collected from the medical records. RESULTS: 70.7 per cent of dogs showed an improvement in respiratory signs following rhinoplasty and palatoplasty. This improvement was associated with the severity of inspiratory efforts and the Poncet score on presentation, but not with any other clinical sign or anatomical abnormality found during BOAS assessment, nor by the degree of craniofacial shortening as determined by CT-scan. Presurgical snoring was positively associated with the degree of narrowing of pharyngeal dimensions. CONCLUSIONS: Dogs presenting with clinical signs of BOAS benefit from rhinoplasty and palatoplasty alone. The degree of narrowing of pharyngeal dimensions appears to be associated with severity of snoring while soft palate length alone was not.

COMPUTED TOMOGRAPHIC, RADIOGRAPHIC, AND ENDOSCOPIC TRACHEAL DIMENSIONS IN ENGLISH BULLDOGS WITH GRADE 1 CLINICAL SIGNS OF BRACHYCEPHALIC AIRWAY SYNDROME.

Tracheal hypoplasia is commonly seen in English Bulldogs affected with brachycephalic airway syndrome. Previously published diagnostic criteria for tracheal hypoplasia in this breed have been a radiographic tracheal diameter:tracheal inlet ratio (TD:TI) < 0.12 or a tracheal diameter:third rib diameter ratio (TD:3R) < 2.0. Computed tomography has become increasingly used for airway evaluation, however published information is lacking regarding CT tracheal dimensions in English Bulldogs. Objectives of this prospective cross-sectional study were to describe radiographic and CT tracheal dimensions in a sample of clinically normal English Bulldogs and compare these values with tracheoscopy scores. Computed tomography (n = 40), radiography (n = 38), and tracheoscopy (n = 40) studies were performed during a single general anesthesia session for each included dog. Tracheal measurements were recorded at three locations: cervical, thoracic inlet, and thorax. Tracheal diameters were narrowest at the thoracic inlet with all techniques. Computed tomographic measurements averaged 19% greater than radiographic measurements. All included dogs had radiographic tracheal measurements greater than the previously published criteria for tracheal hypoplasia. Mean CT TD:TI was 0.26 (± 0.03, 0.20-0.33), and mean CT TT:3R was 2.27 (± 0.24, 1.71-2.74). Radiographic TD:TI and CT TD:TI were significantly correlated (P = 0.00); however radiographic TT:3R and CT TT:3R were not significantly correlated (P = 0.25). Tracheoscopy identified hypoplastic changes in all dogs and tracheoscopy scores were not correlated with CT or radiography diameter measurements. In conclusion, findings indicated that some CT and radiographic tracheal diameter measurements were comparable in English Bulldogs however diameters for both imaging techniques were not comparable with tracheoscopy scores.