Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review.

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Prognostic factors for short-term survival of dogs that experience postattenuation seizures after surgical correction of single congenital extrahepatic portosystemic shunts: 93 cases (2005-2018).

OBJECTIVE: To identify prognostic factors for short-term survival of dogs that experience seizures within 7 days after surgical correction of single congenital extrahepatic portosystemic shunts (cEHPSS). STUDY DESIGN: Multi-institutional retrospective study. SAMPLE POPULATION: Ninety-three client-owned dogs. METHODS: Medical records at 14 veterinary institutions were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 1, 2005 through February 28, 2018 and experienced postattenuation seizures (PAS) within 7 days postoperatively. Logistic regression analysis was performed to identify factors associated with 1-month survival. Factors investigated included participating institution, signalment, shunt morphology, concurrent/historical conditions, presence of preoperative neurologic signs, presence of preoperative seizures, aspects of preoperative medical management, surgical details including method and degree of shunt attenuation, type of PAS (focal only or generalized ± focal), drugs administered as part of the treatment of PAS, and development of complications during treatment of PAS. RESULTS: Thirty (32.3%) dogs survived to 30 days. Seventy-six (81.7%) dogs experienced generalized PAS. Factors positively associated with short-term survival included having a history of preoperative seizures (P = .004) and development of focal PAS only (P = .0003). Most nonsurvivors were humanely euthanized because of uncontrolled or recurrent seizures. CONCLUSION: Dogs that experienced PAS that had a history of preoperative seizures and those that experienced focal PAS only had significantly improved short-term survival. CLINICAL SIGNIFICANCE: The results of this study provide information that will help in the counseling of owners who seek treatment for PAS after surgical correction of cEHPSS. © 2020 The American College of Veterinary Surgeons.

Fluoroscopy-guided balloon dilation of a proximal urethral stricture caused by a urethral membrane in a female cat.

CASE SUMMARY: A proximal urethral stricture was diagnosed by retrograde urethrogram in a 2-year-old female neutered cat, which was referred following a 2-month history of stranguria, pollakiuria and urinary incontinence. Cystoscopic examination confirmed the presence of a severe narrowing of the proximal urethra near to the bladder neck, consisting of a membrane arising from the urethral mucosa. Fluoroscopy-guided balloon dilation was performed. Twelve months after the procedure, the cat did not show any recurrence of clinical signs. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first report of a proximal urethral stricture in a cat. Management by fluoroscopy-guided balloon dilation proved to be a successful and minimally invasive option with an excellent outcome.

Effect of osteoarthritis on the repeatability of patella tendon angle measurement in dogs.

OBJECTIVE: To evaluate the influence of osteoarthritis on the measurement of patella tendon angle (PTA) and determine intraobserver and interobserver variability. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Eighty-seven mediolateral radiographs that were obtained prior to tibial tuberosity advancement. METHODS: Radiographic osteoarthritis was scored by 2 observers using guidelines derived from the International Elbow Working Group Protocol. Patella tendon angle was measured by 3 observers on 3 occasions, with at least 7 days between measurements. The data were statistically analyzed via weighted κ and Kruskal-Wallis testing. RESULTS: A fair strength of agreement was found among observers scoring osteoarthritis, with the same grades in 48% of radiographs. The intraobserver average bias between PTA measurements 1 and 3 ranged from -0.38° to -0.94°. Interobserver bias in angle measurement ranged from -0.92° to -2.00°. Observer 1 had the narrowest range of PTA differences (12.1°), and observer 3 had the highest range of PTA differences (23.5°). Observer 2 had the lowest mean bias (-0.38°). The mean bias was lowest between observers 1 and 2 (-0.92°) and highest between observers 1 and 3 (-2.0°). The mean intraobserver standard deviation of the PTA measurement differences was 2.90°, and interobserver standard deviation of the PTA measurement differences was 2.26°. The degree of osteoarthritis did not influence PTA measurements or their variability. CONCLUSION: The current study did not find evidence of an influence of osteoarthritis on PTA or on the repeatability of measurements. CLINICAL SIGNIFICANCE: Our findings suggest that osteoarthritis should not affect the radiographic planning for tibial tuberosity advancement surgery. The high variances in PTA measurement in less experienced observers may influence the clinical outcome of surgery.

Imaging characteristics and treatment of a penetrating brain injury caused by an oropharyngeal foreign body in a dog.

A 4-year-old Border collie was presented with one episode of collapse, altered mentation, and a suspected pharyngeal stick injury. Magnetic resonance imaging (MRI) and computed tomography showed a linear foreign body penetrating the right oropharynx, through the foramen ovale and the brain parenchyma. The foreign body was surgically removed and medical treatment initiated. Complete resolution of clinical signs was noted at recheck 8 weeks later. Repeat MRI showed chronic secondary changes in the brain parenchyma. To the authors' knowledge, this is the first report of the advanced imaging findings and successful treatment of a penetrating oropharyngeal intracranial foreign body in a dog.

Establishment of normal anatomical radial angles in cats.

OBJECTIVES: 1) To describe a radiographic method for determination of joint orientation lines and anatomical joint angles in orthogonal planes of feline radii; 2) to establish a range of normal radial joint orientation angles and anatomical axes in a feline population; and 3) to assess the repeatability and reliability of this methodology. METHODS: The radial anatomical axis, elbow and carpal joint reference lines, and the intersecting angles of each: anatomical medial proximal (aMPRA) and lateral distal radial angles (aLDRA), anatomical caudal proximal (aCdPRA) and distal radial angles (aCdDRA), and sagittal procurvatum (SP) were determined on the orthogonal radiographs of 14 feline limbs. Intra- and inter-observer agreement was determined based on repeated independent readings by two observers using Bland-Altman plots. RESULTS: The mean ± standard deviation (SD) and 95% confidence interval (CI) for the feline radii were: aMPRA 70.97 ± 3.38° (70.07 - 71.88°), aLDRA 91.72 ± 3.26° (90.84 - 92.59°), aCdPRA 100.5 ± 3.14° (99.62 - 101.3º), aCdDRA 79.95 ± 3.77° (78.94 - 80.96°) and SP 11.07 ± 1.87° (10.57 - 11.58°). The highest mean bias found for both observers was -1.6 to -1.8° for the angle aCdDRA. Sagittal procurvatum had the lowest mean bias for intra- and inter-observer. CLINICAL SIGNIFICANCE: The results obtained showed that the methodology used in our study was repeatable and reliable. The values established for the normal radial anatomical angles are relevant for future use as a reference for surgical treatment of angular deformities, malunions, non-unions, comminuted fractures, and future orthopaedic research.