A randomized, prospective, comparative trial of a variable-angle versus fixed-angle endoscope for exploratory thoracoscopy in canine cadavers.

OBJECTIVE: To compare the efficacy of a variable-angle endoscope (VAE) for canine thoracoscopic exploration to a traditional fixed-angle endoscope (FAE). STUDY DESIGN: Randomized, prospective, comparative study. SAMPLE POPULATION: Five fresh canine cadavers. METHODS: Twelve predetermined anatomical locations were labeled after median sternotomy in each cadaveric thorax. Two board-certified veterinary surgeons performed thoracoscopic evaluation of each thorax using a fixed-angle (30°) and a variable-angle (0°-120°) endoscope with and without lungs mechanically ventilated. The order of surgeon, lung ventilation, and endoscope were determined using a randomized block design. Time to visualize each anatomical location was compared for surgeon, endoscope, and lung ventilation status. Primary outcome measures were time to individual anatomical location, total simulated thoracoscopic exploration time, and ability to identify anatomical location within the designated time period. RESULTS: Lung ventilation (difference = 184 seconds, P = .015, 95% CI = 45-342 seconds) and endoscope type (difference = 112 seconds, P = .029; 95% CI = 10-213 seconds) had an effect on the cumulative time for complete thoracoscopic exploration. The VAE shortened the time to identify three of the 12 anatomical locations when controlling for the effects of lung ventilation. Use of the VAE did not improve time to identification for any locations compared to the FAE when lungs were not ventilated. The VAE facilitated significantly shorter cumulative thoracoscopic exploration time compared with the FAE. Failure to identify predetermined locations was more common with the FAE than with the VAE. CONCLUSION: Use of a rigid VAE decreased cumulative thoracoscopic exploration time and provided an alternative to one-lung ventilation for circumventing the visual impediments of lung ventilation. CLINICAL SIGNIFICANCE: This cadaveric study provides evidence that one-lung ventilation and use of a VAE may improve surgeon efficiency during exploratory thoracoscopy.

Pilot evaluation of a novel unilateral onychectomy model and efficacy of an extended release buprenorphine product.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs), transdermal fentanyl patches, and transmucosal buprenorphine are probably the most commonly used options for providing post-operative analgesia in the early at-home period. However, these require daily administration or are associated with abuse concerns. One of the significant unmet needs in veterinary surgery and pain management is for longer acting opioids for cats to effectively bridge the gap between the in-hospital and at-home recovery periods. A proof of concept study of an extended release formulation of buprenorphine HCL (ER-Bup) was conducted using objective kinetic measures and a unilateral onychectomy model. Using a blinded, randomized, two period crossover design, four cats were allocated to control (saline) or ER-Bup (0.6 mg/kg, subcutaneously [SC]) treatment groups. All animals underwent a unilateral forelimb onychectomy per period with a washout/recovery period in between. Observational pain scores and kinetic data (using a pressure sensitive walkway [PSW]) were collected prior to (baseline) and at intervals for 72 h following surgery. Symmetry indices were derived for kinetic variables (peak vertical force [PVF]; vertical impulse [VI]) of each forelimb for landing following a jump and for walking. A rescue analgesic protocol was in place. Effect of surgery and treatment were evaluated using a mixed model statistical approach. RESULTS: No cats required rescue analgesics based on subjective pain score. ER-Bup had a positive influence on subjective pain scores during the 72 h postsurgery (p = 0.0473). PVF and VI of the operated limb were significantly decreased for both landing (p < 0.0001 and p < 0.0001) and walking (p < 0.0001 and p < 0.0001 respectively) compared to control. ER-Bup resulted in significantly decreased asymmetry in limb use during landing (PVF, p < 0.0001; VI, p < 0.0001) and walking (PVF, p = 0.0002, VI, p < 0.0001). The novel use of data collected following a jump from an elevated platform appeared to provide all desired information and was easier to collect than walking data. CONCLUSION: This study demonstrates that SC administration of ER-Bup may be an effective analgesic for a 72 h period postoperatively. Furthermore, landing onto a PSW from an elevated perch may be a useful and efficient way to assess analgesics in cats using a unilateral model of limb pain.

Prevalence of radiographic appendicular osteoarthritis and associated clinical signs in young dogs.

This study aimed to determine the prevalence of osteoarthritis (OA) and associated clinical signs in young dogs. Owners of dogs aged 8 months-4 years from a single practice, were contacted in random order, to participate in a general health screen. Clinical and orthopedic examinations were performed. Each joint was scored for pain reactions (0-4). Orthogonal radiographs of all joints were made under sedation. Each joint was scored for radiographic OA (rOA) severity on an 11-point scale. Clinical OA (cOA) was defined as an overlap of rOA and joint pain in ≥ 1 joint. Owners completed OA questionnaires. The owners of 123 dogs agreed to participate. Overall, 39.8% (49/123) of dogs had rOA in ≥ 1 joint, and 16.3% (20/123) or 23.6% (29/123) dogs had cOA, depending on the cut-off value of joint pain; moderate (2), or mild (1), respectively. Owners of dogs with cOA observed signs of impairment in approximately 30% of cases. Only 2 dogs with cOA were receiving OA pain management. The most commonly affected joints in descending order of frequency were elbow, hip, tarsus, and stifle. Radiographically visible OA is common in young dogs, and 40-60% of dogs with rOA had cOA. However, OA-pain appears underdiagnosed and undertreated in young dogs.

Creation of a Continent Urinary Bladder Reservoir Vascularized by Omentum as a Possible Surgical Option for Canine Trigonal/Urethral Urothelial Carcinoma.

Surgical procedures that maintain continence with minimal complication following resection of trigono-urethral urothelial carcinoma (UC) are limited in canines; therefore, palliative options are often pursued. A feasible tumor resection option may improve disease control and survival. The study's objective was to evaluate a continent urine reservoir created from the urinary bladder body and vascularized solely by omentum. We hypothesized that a viable urine reservoir could be created, and staged omentalization would provide improved vascularity. Nine normal female Beagles were randomized to one of three groups. Group A urinary bladders were transected cranial to the ureteral papillae to create a closed bladder vesicle which was concomitantly omentalized. Group B underwent omentalization two weeks prior to vesicle creation. Based on Group A and B results, Group C underwent neoureterocystostomy and omentalization followed by neoreservoir formation and tube cystostomy 2 weeks later. Serial ultrasounds and histopathology confirmed adequate omental neovascularization in Groups B and C with continent Group C neoreservoirs maintained for 2 months. Some pylectasia and ureteral dilation was documented in all Group C dogs at variable timepoints. Progressive hydroureteronephrosis developed in 2/6 kidneys. Transient azotemia was noted in only 1 Group C dog, although all developed treatable urinary tract infections. The sample size is limited, and the efficacy of this technique in providing disease control for UC is unknown. However, this novel option could allow for primary UC resection while providing continence and limiting complications. Postoperative local or systemic adjuvant therapy, ultrasonographic neoreservoir monitoring, and BRAF analysis would be indicated.

A lateral surgical approach to the larynx may impair cervical esophageal function in dogs.

OBJECTIVE: To determine whether muscle-sparing laryngoplasty results in fewer changes in swallowing function compared to standard surgical treatment for laryngeal paralysis. ANIMALS: 12 clinically normal sexually intact male Beagles. PROCEDURES: Group A dogs (n = 4) had a standard approach to the larynx, with left arytenoid cartilage lateralization. Group B dogs (n = 4) had a muscle-sparing laryngoplasty performed with the thyropharyngeus muscle fibers bluntly separated, and the cricoarytenoideus dorsalis muscle spared. Pre- and 24-hour postoperative fluoroscopic swallowing studies were performed and graded. Larynges were harvested after humane euthanasia, and glottic area was measured. Group C dogs (n = 4) acted as controls, with surgical dissection ending lateral to the thyropharyngeus muscle, arytenoid lateralization not performed, and the dogs not euthanized. The study was performed between October 15, 2011 and May 15, 2021. RESULTS: Changes in pharyngeal and upper esophageal sphincter function were not detected in any group. There was no difference in glottic area between treatment groups. Aspiration of liquid was not a consistent finding. Two dogs in each treatment group developed moderate to severe cervical esophageal paresis. This did not occur in control dogs. CLINICAL RELEVANCE: We found no evidence to support our hypothesis that muscle-sparing laryngoplasty results in less severe changes in swallowing function compared to a standard technique. The cervical esophageal paresis identified in both treatment groups could increase the risk of postoperative aspiration pneumonia in dogs treated for laryngeal paralysis via a lateral approach to the larynx. Further study to determine the frequency, cause, and duration of esophageal dysfunction is warranted.

Serum artemin is not correlated with sensitivity within dogs with naturally occurring osteoarthritis pain.

Osteoarthritis (OA) pain is associated with peripheral and central sensitization in humans and results in widespread increased sensitivity across the body. Sensitization contributes to the OA-associated pain (OAP) state. We recently identified increased levels of an endogenous neurotrophic factor, artemin (ARTN), in dogs with OAP compared to healthy pain-free controls. Circulating ARTN released from damaged tissues in OA, may play a central role in widespread sensitivity and pain. However, the relationship between ARTN and somatosensory sensitivity remains unknown. The study aimed to assess the relationship between serum ARTN concentrations and measures of sensitivity in dogs with OAP using quantitative sensory testing. We hypothesized that there would be a positive association between circulating ARTN and increased sensitivity to mechanical and thermal stimuli in dogs with OAP. We used linear and logistic regression models to assess the relationship between ARTN, sensitization, and pain within a cohort of 43 dogs with spontaneous OAP. Serum ARTN was not associated with the degree of sensitization within dogs with OAP. Further, across dogs with varying OAP severity, we did not find any association between ARTN, and clinical measures of joint pain and disability. Although a relationship between ARTN and joint pain was not ruled out.

Meniscal mineralization in domestic cats.

OBJECTIVE: To (1) determine prevalence of radiographically detectable meniscal mineralization in domestic cats and (2) to evaluate the association between meniscal mineralization and degenerative joint disease (DJD). STUDY DESIGN: Prospective study. ANIMALS: Client-owned cats (n=100) and 30 feline cadavers. METHODS: Randomly selected client-owned cats were used to determine the prevalence of meniscal mineralization. Stifles from feline cadavers were used to evaluate the relationship between meniscal mineralization (using high-resolution X-ray), radiographic DJD, and cartilage damage. Menisci were evaluated histologically. RESULTS: Forty-six percent of the client-owned cats had meniscal mineralization detected in 1 or both stifles. Pain scores were not significantly different between stifles with meniscal mineralization and those with no radiographic pathology (P=.38). Thirty-four of 57 cadaver stifles had meniscal mineralization, which was always located in the cranial horn of the medial meniscus. Percentage mineralization of the menisci was significantly correlated with the cartilage damage score of the medial femoral (r(2)=0.6; P<.0001) and tibial (r(2)=0.5; P<.0001) condyles as well as with the total joint cartilage damage (r(2)=0.36; P<.0001) score and DJD score (r(2)=0.8; P<.0001). CONCLUSION: Meniscal mineralization is a common condition in domestic cats and seems to indicate medial compartment DJD. CLINICAL RELEVANCE: Clinical significance of meniscal mineralization is uncertain. Further work is needed to determine if the meniscal mineralization is a cause, or a consequence of joint degeneration.

Lower urinary tract transitional cell carcinoma in cats: Clinical findings, treatments, and outcomes in 118 cases.

BACKGROUND: Lower urinary tract transitional cell carcinoma (TCC) is an important but rarely described disease of cats. OBJECTIVES: To report the clinical characteristics, treatments, and outcomes in a cohort of cats with lower urinary tract TCC and to test identified variables for prognostic relevance. ANIMALS: One-hundred eighteen client-owned cats with lower urinary tract carcinoma. METHODS: Medical records were retrospectively reviewed to obtain information regarding clinical characteristics, treatments, and outcomes. Recorded variables were analyzed statistically. RESULTS: Median age of affected cats was 15 years (range, 5.0-20.8 years) and median duration of clinical signs was 30 days (range, 0-730 days). The trigone was the most common tumor location (32/118; 27.1%) as assessed by ultrasound examination, cystoscopy, or both. Treatment was carried out in 73 of 118 (61.9%) cats. Metastatic disease was documented in 25 of 118 (21.2%) cats. Median progression-free survival and survival time for all cats were 113 days (95% confidence interval [CI], 69-153) and 155 days (95% CI, 110-222), respectively. Survival increased significantly (P < .001) when comparing cats across the ordered treatment groups: no treatment, treatment without partial cystectomy, and treatment with partial cystectomy. Partial cystectomy (hazard ratio [HR], 0.31; 95% CI, 0.17-0.87) and treatment with nonsteroidal anti-inflammatory drugs (HR, 0.55; 95% CI, 0.33-0.93) were significantly associated with longer survival times. CONCLUSIONS AND CLINICAL IMPORTANCE: The results support treatment using partial cystectomy and NSAIDs in cats with TCC.

Functional outcome measures in a surgical model of hip osteoarthritis in dogs.

BACKGROUND: The hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence. However, current animal models of hip osteoarthritis have not been assessed using many of the functional outcome measures used in orthopaedics, a characteristic that could increase their utility in the evaluation of therapeutic interventions. The canine hip shares similarities with the human hip, and functional outcome measures are well documented in veterinary medicine, providing a baseline for pre-clinical evaluation of therapeutic strategies for the treatment of hip osteoarthritis. The purpose of this study was to evaluate a surgical model of hip osteoarthritis in a large laboratory animal model and to evaluate functional and end-point outcome measures. METHODS: Seven dogs were subjected to partial surgical debridement of cartilage from one femoral head. Pre- and postoperative pain and functional scores, gait analysis, radiographs, accelerometry, goniometry and limb circumference were evaluated through a 20-week recovery period, followed by histological evaluation of cartilage and synovium. RESULTS: Animals developed histological and radiographic evidence of osteoarthritis, which was correlated with measurable functional impairment. For example, Mankin scores in operated limbs were positively correlated to radiographic scores but negatively correlated to range of motion, limb circumference and 20-week peak vertical force. CONCLUSIONS: This study demonstrates that multiple relevant functional outcome measures can be used successfully in a large laboratory animal model of hip osteoarthritis. These measures could be used to evaluate relative efficacy of therapeutic interventions relevant to human clinical care.

Results of Open Surgical Repair in Patients With Marfan Syndrome and Distal Aortic Dissection.

BACKGROUND: In patients with Marfan syndrome (MFS), distal aortic dissection can necessitate thoracoabdominal aortic aneurysm (TAAA) repair in survivors of acute DeBakey type I dissection and those with DeBakey type III dissection. We examined outcomes of surgical repair of TAAA in patients with MFS with distal aortic dissection. METHODS: Data were analyzed for 127 consecutive TAAA repairs performed between January 2004 and June 2014 in patients with MFS and distal aortic dissection-DeBakey types I (n = 73) and III (n = 54). The median time from dissection onset to TAAA repair was 5.2 years (interquartile range [IQR]: 2.1 to 9.8 years) for the overall group and was longer in patients with DeBakey I (6.5 years, IQR: 3.5 to 13.9 years) than patients with DeBakey III (2.9 years, IQR: 0.6 to 6.0 years, p < 0.001). Eleven patients (9%) had acute or subacute dissection at the time of repair. Sixty-six patients (52%) underwent Crawford extent II TAAA repair. A composite end point, adverse event, was defined as operative death or permanent stroke, renal failure, paraplegia, or paraparesis. RESULTS: Eight patients had adverse events (6%), including 5 operative deaths (4%). There was no permanent stroke and 1 case each of permanent paraplegia and paraparesis. At discharge, 2 early survivors (2%) had renal failure. Extent II repairs did not have substantially different outcomes from other repairs. CONCLUSIONS: In these patients with MFS with aortic dissection, open TAAA repair incurred reasonable operative risk, but improvements are needed to reduce rates of renal failure. Extent II TAAA repair does not appear to increase operative risk in patients with MFS.

Assessment of cord dorsum potentials from caudal nerves in anesthetized clinically normal adult dogs without or during neuromuscular blockade.

OBJECTIVE: To assess the feasibility of measuring cord dorsum potentials (CDPs) in anesthetized clinically normal dogs after caudal nerve stimulation, determine the intervertebral site of maximum amplitude and best waveform of the CDP, and evaluate the effects of neuromuscular blockade. ANIMALS: 8 male and 4 female dogs (age, 1 to 5 years). PROCEDURES: Dogs were anesthetized, and CDPs were recorded via needles placed on the dorsal lamina at intervertebral spaces L1-2 through L7-S1. Caudal nerves were stimulated with monopolar electrodes inserted laterally to the level of the caudal vertebrae. Dogs were tested without and during neuromuscular blockade induced with atracurium besylate. The CDP latency and amplitude were determined from the largest amplitude tracings. RESULTS: CDPs were recorded in 11 of 12 dogs without neuromuscular blockade and in all dogs during neuromuscular blockade. The CDP was largest and most isolated at the L4-5 intervertebral space (3 dogs) or the L5-6 intervertebral space (9 dogs); this site corresponded to the segment of insertion of the first caudal nerve. Onset latencies ranged from 2.0 to 4.7 milliseconds, and there was no effect of neuromuscular blockade on latencies. Amplitudes of the CDPs were highly variable for both experimental conditions. CONCLUSIONS AND CLINICAL RELEVANCE: CDPs were recorded from all dogs tested in the study; neuromuscular blockade was not critical for successful CDP recording but reduced muscle artifact. This technique may be useful as a tool to assess the caudal nerve roots in dogs suspected of having compressive lumbosacral disease or myelopathies affecting the lumbar intumescence.