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Objective: To report local progression and survival in dogs following surgery and postoperative definitive radiotherapy (dRT) for management of soft tissue sarcoma (STS) and to evaluate risk factors for local progression and survival., Methods: Records were retrospectively reviewed at 9 referral hospitals for dogs managed with postoperative dRT between January 1, 2010, and January 1, 2020, following surgery for STS. Data related to presentation, surgery, dRT, systemic therapy, and outcome were abstracted. Selected variables were assessed for association with local progression and overall survival., Results: 272 dogs were included. Histologic grade was reported in 249 dogs: 102 were grade 1 (40.9%), 120 were grade 2 (48.2%), and 27 were grade 3 (10.8%). Local progression was suspected or confirmed in 56 dogs. Local progression rates were similar for grade 1 (24 of 89 [26.7%]), grade 2 (23 of 111 [20.7%]), and grade 3 tumors (6 of 22 [27.3%]). Previous recurrence (P = .010) and subsequent distant metastasis (P = .014) were associated with more frequent local progression; intensity-modulated radiotherapy was associated with decreased local progression (P = .025) compared to other forms of delivery. Age (P = .049), grade (P = .009), previous recurrence (P = .009), and institution type for surgery (P = .043) were associated with overall survival., Conclusions: Outcomes for most dogs were good; however, the frequency of local progression indicates an ongoing need to critically appraise local management strategies, particularly for low-grade STS. Intensity-modulated radiotherapy was associated with lower rates of local progression and may be preferred to less precise forms of delivery., Clinical Relevance: These data may guide clinicians when making decisions regarding dRT for management of STS.

Objective: To determine the rate of nodal metastasis in dogs with thyroid cancer and evaluate whether immunohistochemistry (IHC) identifies additional metastases beyond evaluation with H&E., Animals: 70 prospectively enrolled client-owned dogs with thyroid cancer managed with thyroidectomy., Methods: Dogs underwent thyroidectomy with concurrent elective bilateral medial retropharyngeal (MRP) ± deep cervical lymphadenectomy. Thyroid tumors and associated lymph nodes were reviewed by a single board-certified pathologist. Immunohistochemistry was used for all primary tumors (thyroid transcription factor-1 and calcitonin) to support a diagnosis of follicular or medullary carcinoma. Lymph nodes without evidence of metastasis after H&E review were labeled with the antibody associated with the wider uptake in the primary tumor., Results: 77 thyroid cancers were resected from the 70 dogs enrolled, including 61 (79.2%) follicular, 8 (10.7%) medullary, and 7 (9.3%) mixed follicular/medullary carcinomas, with 1 (1.3%) carcinosarcoma. Twelve dogs had evidence of nodal metastasis following H&E review. Occult micrometastasis was identified in 1 dog following nodal IHC, resulting in documented metastasis in 13 of 70 (18.6%) dogs. Metastasis was more common with medullary (5/8) and follicular/medullary carcinoma (3/7) than follicular carcinoma (5/61). All MRP metastases were ipsilateral (7/77 [9.1%]), without contralateral MRP metastases (0/62). Fourteen of 41 (34.1%) deep cervical lymph nodes were metastatic., Clinical Relevance: Nodal metastasis was uncommon for follicular carcinoma but was seen in > 50% of dogs with thyroid cancer involving a medullary component. Routine nodal IHC appears to be low yield for thyroid carcinoma. Extirpation of ipsilateral MRP and identifiable deep cervical lymph nodes is recommended with thyroidectomy until detailed preoperative risk stratification becomes available.

Objective: Thromboelastography (TEG) is a whole blood assay that yields global assessment of hemostasis, as it evaluates clot time, strength, and kinematics of clot formation and lysis. The main objective was to describe preoperative TEG findings in dogs that had an adrenalectomy performed and, secondarily, to describe TEG findings in the dogs with or without hyperadrenocorticism (HAC)., Animals: 30 dogs that had preoperative TEG and adrenalectomy performed., Methods: Medical records between 2018 and 2022 were reviewed. Signalment, diagnostic data, and perioperative treatment were abstracted., Results: 53% (16/30) of the dogs were hypercoagulable, and none were hypocoagulable. Based on histopathology, 6 of 9 dogs with adenocarcinoma were hypercoagulable, 4 of 8 with pheochromocytoma were hypercoagulable, and 6 of 10 with adenoma were hypercoagulable. None of the 3 dogs with other histopathologic diagnoses or combinations of diagnoses (adrenocortical hyperplasia, poorly differentiated sarcoma, and both adrenocortical adenocarcinoma and pheochromocytoma) were hypercoagulable. Of the 14 dogs tested preoperatively for HAC, 4 of 8 HAC dogs were hypercoagulable and 2 of 6 non-HAC dogs were hypercoagulable., Clinical Relevance: The present report describes for the first time TEG findings for dogs undergoing adrenalectomy and suggests that the majority of dogs with adrenal neoplasia are hypercoagulable based on TEG results.

Objective: To report the survival times in dogs diagnosed with adrenal tumors with vascular or soft tissue invasion that did not undergo adrenalectomy., Animals: Retrospective case series of 32 client-owned dogs., Methods: The medical records of a referral veterinary hospital were reviewed to identify dogs that were diagnosed with an invasive adrenal mass and did not undergo adrenalectomy between January 2013 and December 2022. Data collected included signalment, examination findings, and diagnostic results from the initial presentation. Descriptive statistics were calculated to summarize dog signalment information, and Kaplan-Meier survival analysis was performed for calculation of median survival time., Results: Most dogs (n = 28) had vascular invasion, primarily into the caudal vena cava. Surgery was offered but not pursued due to perceived risk of sudden death (n = 5), risk of hemorrhage (4), or concurrent diagnosis of disseminated intravascular coagulation (1). Only 1 dog pursued stereotactic body radiation therapy, and 1 was prescribed toceranib phosphate (Palladia). Of these 32 dogs, 30 (93.8%) died or were euthanized and 2 (6.2%) dogs survived. The median follow-up time was 49 days (range, 0 to 1,910 days). The median survival time was 50 days (95% CI, 4 to 194 days). The most common cause of death or euthanasia was hemoabdomen (n = 8)., Clinical Relevance: Nonsurgical management of invasive adrenal tumors was associated with short survival times in this case series.

Objective: To determine the incidence of complications in the intraoperative and postoperative period for dogs undergoing nephrectomy for renal disease., Animals: 69 dogs., Methods: Medical records of dogs undergoing nephrectomies for renal disease were reviewed for signalment, date of surgery, results of blood analyses, and intra- and postoperative complications. Long-term follow-up was obtained via client telephone interview or referring veterinarian medical records. A Fisher exact test was used to assess the relationship between postoperative acute kidney injury and NSAID administration with long-term development of chronic kidney disease., Results: Complications occurred in 44.9% and 42.6% of dogs in the intraoperative and postoperative periods, respectively. Most of these were lower-grade complications, though a total of 7 dogs died during the postoperative period. An acute kidney injury was diagnosed in 12 dogs postoperatively, with 2 dogs euthanized due to the severity of the injury. Long-term follow-up was available for 53 dogs, with 24 (45.3%) dogs developing chronic kidney disease. Postoperative acute kidney injury (P = .385) and NSAID administration (P = .519) were not statistically associated with the development of chronic kidney disease in this population., Clinical Relevance: Unilateral nephrectomy is associated with high intraoperative and postoperative complication rates in dogs. Chronic kidney disease was diagnosed in almost 50% of the population with available long-term follow-up.

Objective: To report the clinical characteristics, treatments, and outcomes in a cohort of dogs with histologically confirmed retroperitoneal sarcoma (RPS) and to identify potential variables of prognostic significance., Animals: 46 client-owned dogs from 10 clinics with histopathologic diagnosis of a sarcoma originating from the retroperitoneal space., Methods: Medical records were retrospectively reviewed to obtain information regarding clinical characteristics, treatments, and outcomes. Recorded variables were analyzed to report descriptive data for all cases and overall survival time. Multivariate analysis was utilized to evaluate prognostic factors for overall survival., Results: Hemangiosarcoma was the most common histologic subtype diagnosed (76.1%). Cytoreductive and curative intent surgical excision of the RPS was attempted in 12 and 22 dogs, respectively; 12 dogs underwent no surgery or had an exploratory laparotomy with incisional biopsy only. Nineteen dogs received adjuvant chemotherapy, either injectable or metronomic, and 1 dog received adjuvant radiation therapy. Fourteen of the 34 (41.2%) surgically treated dogs developed evidence of local recurrence, but there was no difference in local recurrence when comparing dogs categorized as curative intent versus cytoreductive surgery. The median overall survival time was 238 days. On multivariable analysis, treatment approach was associated with survival with surgical excision (vs palliative treatment) and adjuvant chemotherapy following surgery being protective against death. A diagnosis of hemangiosarcoma was associated with a greater hazard of death., Clinical Relevance: This study demonstrates a substantially greater survival time than previously published and suggests a survival benefit from surgical excision and adjuvant chemotherapy.

Objective: To report clinical features and outcomes of cats undergoing either stereotactic radiotherapy (SRT) or surgical excision for the treatment of intracranial meningioma., Animals: 61 client-owned cats., Methods: Medical records were retrospectively reviewed of cats with intracranial meningiomas that were treated with surgical removal and/or SRT between 2005 and 2017. Signalment, clinical signs, duration of clinical signs, diagnostic imaging reports, histopathology reports, treatment protocol, complications, recurrence or progression, and survival time were obtained from the medical record and through follow-up phone calls., Results: Of the 61 patients, 46 had surgery, 14 had SRT, and 1 had surgery followed by SRT for initial treatment. Significantly more cats that underwent surgery had peritreatment complications compared to the SRT group (P < .0001). Cats that received surgery initially had a significantly longer median survival time (MST) of 1,345 days compared to the MST of 339 days for the SRT cats (P = .002). Fourteen (30%) cats in the surgery group and 4 cats in the SRT group (28%) had MRI- or CT-confirmed tumor regrowth or new tumor growth (P = 1.00). Five cases that had SRT for subsequent recurrence had an MST of 700 days (range, 335 to 1,460 days) after the last treatment., Clinical Relevance: SRT proved to be a safe, alternative treatment option for feline patients with intracranial meningiomas; however, the survival times with surgery alone were significantly longer. SRT for the treatment of recurrence following initial surgery may show promising results.

Objective: To conduct a retrospective multi-institutional study reporting short- and long-term outcomes of adrenalectomy in patients presenting with acute hemorrhage secondary to spontaneous adrenal rupture., Animals: 59 dogs and 3 cats., Methods: Medical records of dogs and cats undergoing adrenalectomy between 2000 and 2021 for ruptured adrenal masses were reviewed. Data collected included clinical presentation, preoperative diagnostics, surgical report, anesthesia and hospitalization findings, histopathology, adjuvant treatments, and long-term outcome (recurrence, metastasis, and survival)., Results: Median time from hospital admission to surgery was 3 days, with 34% of surgeries being performed emergently (within 1 day of presentation). Need for intraoperative blood transfusion was significantly associated with emergent surgery and presence of active intraoperative hemorrhage. The short-term (≤ 14 days) complication and mortality rates were 42% and 21%, respectively. Negative prognostic factors for short-term survival included emergent surgery, intraoperative hypotension, and performing additional surgical procedures. Diagnoses included adrenocortical neoplasia (malignant [41%], benign [12%], and undetermined [5%]), pheochromocytoma (38%), a single case of adrenal fibrosis and hemorrhage (2%), and a single case of hemangiosarcoma (2%). Local recurrence and metastasis of adrenocortical carcinoma were confirmed in 1 and 3 cases, respectively. Overall median survival time was 574 days and 900 days when short-term mortality was censored. No significant relationship was found between histopathological diagnosis and survival., Clinical Relevance: Adrenalectomy for ruptured adrenal gland masses was associated with similar short- and long-term outcomes as compared with previously reported nonruptured cases. If hemodynamic stability can be achieved, delaying surgery and limiting additional procedures appear indicated to optimize short-term survival.

Objective: To evaluate the role of simulation models and previous surgical experience on subjective and objective stress levels of students performing their 1st elective surgery within the veterinary curriculum., Sample: 141 third-year veterinary students., Methods: Using a pre-post experimental design, salivary alpha-amylase, and cortisol were evaluated as markers of physiologic stress response before students' first elective surgery. Student self-reported State-Trait Anxiety Inventory (STAI) scores and quantitative measures of experience were correlated to biomarker results., Results: No association was found for change in salivary biomarkers of stress, alpha-amylase, and cortisol, between baseline and presurgical samples accounting for gender, age, type of elective surgery performed, previous surgical experience, or simulation model use. Salivary cortisol levels were markedly elevated falling between the 66th and 99th percentile compared to an age and gender-matched population. Salivary alpha-amylase levels were also 2 to 3 times higher than those recorded by other health professionals. Veterinary student STAI scores were high falling between the 65th and 73rd percentile compared to working adults in the general population., Clinical Relevance: Veterinary students' salivary cortisol, alpha-amylase, and STAI scores fell into the upper 2/3rds of the general population, demonstrating a high level of stress. Simulation models and previous surgical experience were not associated with decreased stress. Further evaluation of the implementation of high-fidelity simulation models and the role of stress on performance is indicated.

Objective: To compare the success rates for urethral catheterization in clinical patients using the traditional and 2-catheter techniques when placed by personnel of all experience levels., Animals: 38 female cats and dogs weighing less than 10 kg were prospectively enrolled., Methods: Enrolled animals were randomized to have a urethral catheter placed by the traditional technique or the 2-catheter method under sedation or general anesthesia. Any qualified hospital personnel of any experience level were allowed to place the catheter. If after 5 minutes the animal was not successfully catheterized, the alternate method was performed. The previous experience of the catheter placer, animal signalment, animal condition that necessitated catheter placement, time to successful placement, and which technique was successful was recorded., Results: The 2-catheter technique was more successful than the traditional method (60.5% and 34.2%, respectively) for urethral catheterization when used by a variety of hospital personnel. The 2-catheter technique was successful in 63.3% of dogs and 66.6% of cats, while the traditional method was successful in 36.6% of dogs and 33.3% of cats. Eight of 9 (88.9%) novice catheter placers that placed their first urinary catheter in this study succeeded with the 2-catheter technique and only 1 was successful with the traditional method., Clinical Relevance: The 2-catheter technique has a higher rate of success for placement of female urinary catheters in small patients that are unable to have concurrent digital palpation. This technique may also be helpful in the inexperienced catheter placer population to aid in guidance into the urethral papilla.

Objective: To report the short-term and long-term outcomes of dogs that underwent the modified closed and traditional closed anal sacculectomy procedures for the treatment of anal sac neoplasia., Animals: 90 client-owned dogs., Methods: The medical records of 2 tertiary referral hospitals were reviewed to identify dogs that underwent anal sacculectomy for treatment of anal sac neoplasia between January 2016 and December 2020. Data collected included signalment and preoperative diagnostic findings. The occurrence of intraoperative and postoperative complications, short-term outcomes, and long-term outcomes were also collected. Descriptive statistics were calculated to summarize dog signalment information, and recurrence, metastasis, and survival proportions were compared between techniques using Fisher exact tests., Results: 35 and 55 dogs, respectively, underwent the modified or traditional closed anal sacculectomy procedure. Minor postoperative complications that resolved with minimal intervention occurred in 5 of 35 (14.3%) modified approach dogs and 12 of 55 (21.8%) traditional approach dogs. Tumor recurrence was confirmed in 8 of 35 (22.9%) modified and 8 of 55 (26.4%) traditional approach dogs and was suspected in 3 of 35 (8.6%) and 6 of 55 (13.2%; P = .68), respectively. Confirmed metastatic disease was identified in 8 of 35 (22.9%) and 14 of 53 (26.4%) modified and traditional approach dogs, respectively, and was suspected in 4 of 35 (11.4%) and 7 of 53 (13.2%). Sixty-three (70%) dogs survived to study conclusion., Clinical Relevance: No benefits in complication rate or local recurrence were identified in dogs following the modified approach as opposed to the traditional closed anal sacculectomy technique.

Objective: To provide a video tutorial on how to perform an alternate method for urethral catheterization, the 2-catheter technique., Animals: Small female cats and dogs that are too small for concurrent digital palpation (generally < 10 kg)., Methods: A larger red rubber catheter (18 Fr in dogs, and 10 Fr in cats) is gently fed into the vaginal canal and reflected dorsally, then a smaller urethral catheter can be introduced ventrally, angling downwards at a 45° angle, into the urethral orifice for urinary catheterization., Results: The 2-catheter method is a useful alternative in petite female cats and dogs to improve rates of successful catheterization., Clinical Relevance: The inability to perform concurrent digital palpation in petite female dogs and cats can make urinary catheterization more challenging due to the inability to palpate locoregional anatomic landmarks and without the added manipulation of the catheter tip during placement. Using a second, larger catheter to occlude the vaginal canal similarly to how a finger would during digital palpation can aid in successful catheterization in this challenging subset of veterinary patients.

Objective: To describe the management of extensive hepatectomy in 2 dogs., Animals: A 10-year-old female intact mixed-breed dog (case 1) and an 11-year-old male castrated mixed-breed dog (case 2) were presented for surgical evaluation following diagnosis of a hepatic mass., Clinical Presentation, Progression, and Procedures: 16 months before presentation, case 1 had undergone a left lateral liver lobectomy, which resulted in an incomplete resection of hepatocellular carcinoma. Both dogs underwent surgical excision of the liver mass., Treatment and Outcome: In case 1, surgery consisted of the removal of the remaining left medial lobe, as well as the central division. Case 2 received a complete left and central division hepatectomy. Histopathology confirmed a diagnosis of hepatocellular carcinoma in both dogs. Liver enzyme resolution and lack of tumor recurrence were confirmed with chemistry panel and abdominal ultrasonography in both dogs., Clinical Relevance: This case report describes, for the first time, the clinical management and outcome of extensive hepatectomy in 2 dogs. We propose that extensive hepatectomy, staged or synchronous, is possible in a clinical setting.

Objective: To evaluate hearing loss in Cavalier King Charles Spaniels (CKCS), breed-specific brainstem auditory-evoked response (BAER) testing parameters are needed to help assess the Chiari-like malformation (CM) grade. The purpose of this study was to establish breed-specific BAER data and to determine if BAER indexes differed based on the CM grade. We hypothesized that there would be latency differences based on the CM grade., Animals: 20 CKCS without apparent hearing abnormalities as assessed by the owners., Procedures: Under general anesthesia, CKCS underwent a CT scan (to assess the middle ear), BAER testing, and MRI (to assess the grade of CM)., Results: No CKCS had CM0. Nine (45%) CKCS had CM1; 11 (55%) had CM2. All had at least 1 morphologic abnormality in waveforms. Absolute and interpeak latencies were reported for all CKCS and compared between CM grades. The median threshold for CKCS with CM1 was 39 and for CM2 was 46. Absolute latencies for CKCS with CM2 were consistently longer than those for CKCS with CM1 with the exception of waves II and V at 33 dB. Significant differences were found for wave V at 102 dB ( P = .04) and wave II at 74 dB (P = .008). Interpeak latency comparisons were inconsistent between CM1 and CM2., Clinical Relevance: Breed-specific BAER data for CKCS with CM1 and CM2 were established. The results suggest that CM impacts BAER latency results, but the influence of the malformation is not always statistically significant or predictable.

Objective: To investigate the CT features of cavitary pulmonary lesions and determine their utility to differentiate malignant from benign lesions., Animals: This retrospective study included cases from 5 veterinary medical centers between January 1 2010, and December 31, 2020. Inclusion criteria included having a gas-filled cavitary pulmonary lesion on thoracic CT and definitive diagnosis by either cytology or histopathology. Forty-two animals (27 dogs and 15 cats) were included in this study., Procedures: Medical records systems/imaging databases were searched, and cases meeting inclusion criteria were selected. The CT studies were interpreted by a third-year radiology resident, and findings were reviewed by a board-certified veterinary radiologist., Results: 7 of the 13 lesion characteristics investigated were not statistically associated with the final diagnosis of the lesion, whereas 6 were statistically associated. Those that were associated included the presence of intralesional contrast enhancement, type of intralesional contrast enhancement (heterogenous and homogenous analyzed separately), presence of additional nodules, wall thickness of the lesion at its thickest point, and wall thickness at the thinnest point., Clinical Relevance: Results from the present study showed that thoracic CT imaging of cavitary pulmonary lesions can be used to further refine the list of differential diagnoses. Based on this data set, in lesions that have heterogenous contrast enhancement, additional pulmonary nodules, and wall thickness > 40 mm at their thickest point, it would be reasonable to consider malignant neoplastic disease higher on the list of differentials than other causes.

Objective: To determine the most common indications for cranial surgery and identify risk factors associated with the occurrence of complications and death in the perioperative period following cranial surgery., Animals: 150 dogs and 15 cats., Procedures: For this multi-institutional retrospective case series, medical records of dogs and cats that underwent cranial surgery at any of the 4 participating institutions between 1995 and 2016 were reviewed. Variables were evaluated included species, sex, age, neurolocalization, history of preoperative seizures, surgical approach, histological results, perioperative complications, and outcome. Logistic regression analysis was performed to assess for risk factors for complications., Results: The most common neurolocalization was the forebrain (110/165 [66.7%]), with 94 (57.0%) animals having had seizures preoperatively. The rostrotentorial (116/165 [70.3%]) and caudotentorial (32/165 [19.4%]) surgical approaches were most commonly reported. The most common indication was the treatment of meningioma (75/142 [52.8%]). Complications arose in 58 of the 165 (35.2%) cases within 24 hours and in 86 (52.1%) cases 1 to 10 days postoperatively. Perioperative complications included hypotension (38/165 [23.0%]) and anemia (27/165 [16.4%]). During the postoperative period, the most common complications were neurologic deficits, seizures, postoperative anemia, and aspiration pneumonia. The mortality rate with death or euthanasia perioperatively or ≤ 10 days postoperatively was 14.5% (24/165). Long-term complications occurred in 65 of the 165 (39.4%) animals, with seizures and neurologic deficits being the most common., Clinical Relevance: Cranial surgery was performed most commonly for the removal of neoplastic lesions in dogs and cats, and most complications were not life-threatening.

Objective: To describe a modified approach to closed anal sacculectomy and report the short-term outcomes of dogs that underwent the procedure for treatment of neoplasia., Animals: 16 client-owned dogs., Procedures: Medical records of 1 referral hospital were reviewed to identify dogs that underwent modified closed anal sacculectomy for treatment of anal sac neoplasia between January 2018 and September 2020. Data collected included signalment, examination and diagnostic imaging findings, surgical details, intraoperative and postoperative complications, cytologic and histologic findings, adjuvant treatments, duration of follow-up, and short-term outcome., Results: 15 dogs had apocrine gland anal sac adenocarcinoma, and 1 had a collision tumor. No dogs had intraoperative complications; 1 dog had a minor postoperative complication (paraparesis) that resolved. The median duration of postoperative follow-up was 286 days (range, 67 to 777 days). One dog had confirmed local disease recurrence 290 days after surgery, and 1 had suspected local disease recurrence 203 days after surgery and was euthanized because of systemic disease progression., Conclusions and Clinical Relevance: The modified closed anal sacculectomy was well tolerated in this sample of dogs, with minimal short-term complications. This study provided evidence to justify evaluation of the procedure in a larger number of dogs and assessment of the effects of procedural modifications on postoperative complication rates and time to local recurrence.

Objective: To provide updated information on the distribution of histopathologic types of primary pulmonary neoplasia in dogs and evaluate the effect of postoperative adjuvant chemotherapy in dogs with pulmonary carcinoma., Animals: 340 dogs., Procedures: Medical records of dogs that underwent lung lobectomy for removal of a primary pulmonary mass were reviewed, and histopathologic type of lesions was determined. The canine lung carcinoma stage classification system was used to determine clinical stage for dogs with pulmonary carcinoma., Results: Pulmonary carcinoma was the most frequently encountered tumor type (296/340 [87.1%]), followed by sarcoma (26 [7.6%]), adenoma (11 [3.2%]), and pulmonary neuroendocrine tumor (5 [1.5%]); there was also 1 plasmacytoma and 1 carcinosarcoma. Twenty (5.9%) sarcomas were classified as primary pulmonary histiocytic sarcoma. There was a significant difference in median survival time between dogs with pulmonary carcinomas (399 days), dogs with histiocytic sarcomas (300 days), and dogs with neuroendocrine tumors (498 days). When dogs with pulmonary carcinomas were grouped on the basis of clinical stage, there were no significant differences in median survival time between dogs that did and did not receive adjuvant chemotherapy., Clinical Relevance: Results indicated that pulmonary carcinoma is the most common cause of primary pulmonary neoplasia in dogs; however, nonepithelial tumors can occur. Survival times were significantly different between dogs with pulmonary carcinoma, histiocytic sarcoma, and neuroendocrine tumor, emphasizing the importance of recognizing the relative incidence of these various histologic diagnoses. The therapeutic effect of adjuvant chemotherapy in dogs with pulmonary carcinoma remains unclear and warrants further investigation.

Objective: To provide information about complication rates and the risk factors for complications with mandibulectomy and maxillectomy procedures in dogs., Animals: 459 client-owned dogs that underwent a mandibulectomy or maxillectomy between January 1, 2007, and January 1, 2018., Procedures: Inclusion criteria included a complete medical record that contained an anesthesia record, surgical report, available histopathology results, and results of CBC and serum biochemical analysis before surgery. A minimum follow-up of 90 days after surgery was required., Results: 271 complications occurred in 171 of 459 (37.3%) dogs. Eighteen complications were not given a severity description. Of the remaining 253 complications, most were considered minor (157/253 [62.1%]). Multivariable logistic regression analysis revealed that only increased surgical time had a significant (OR, 1.36; 95% CI, 1.12 to 1.54) association with the occurrence of ≥ 1 complication. For each additional hour of surgery, the odds of complications increased by 36%. Preoperative radiation therapy or chemotherapy increased the odds of incisional dehiscence or oral fistula formation (OR, 3.0; 95% CI, 1.3 to 7.2). Additionally, undergoing maxillectomy, compared with mandibulectomy, increased the odds of incisional dehiscence or oral fistula formation (OR, 1.8; 95% CI, 1.1 to 3.1). Two hundred forty-four of 271 (90.0%) complications occurred in the perioperative period (0 to 3 months after surgery)., Conclusions and Clinical Relevance: Compared with mandibulectomy, performing maxillectomy increased the risk for incisional dehiscence or oral fistula formation. Mandibulectomy and maxillectomy had a moderate risk for a complication.

Objective: To evaluate a novel 2-catheter technique for urethral catheterization in female cats and small dogs and compare the time required for and success rates achieved by use of the novel technique versus traditional methods (blind technique in cats and digital palpation in dogs) as performed by personnel (catheter placers [CPs]) with different levels of experience in urinary catheter placement., Animals: 39 healthy sexually intact female animals (24 cats and 15 dogs weighing < 10 kg)., Procedures: 2 CPs were board certified in veterinary surgery, 1 of whom had experience with the novel technique, and the other did not. The third CP was a veterinary surgical intern who was unfamiliar with the novel technique. For each animal enrolled in the study, 1 CP performed catheterization with the novel technique and traditional methods. Data recorded included the time required for successful catheterization and whether a successful catheterization was achieved within a 3-minute time limit., Results: The overall success rates were 79.5% (31/39 animals) with the novel technique and 43.6% (17/39 animals) with traditional methods. Median times for successful catheter placement were 48 seconds for the novel technique and 41 seconds for traditional methods. Among CPs, success rates or times to successful catheter placement did not differ significantly., Conclusions and Clinical Relevance: Study results suggested that the novel 2-catheter technique for urethral catheterization may be a more efficient option than traditional methods for gaining access to the urinary bladder in cats and small dogs, particularly when patient size limits use of instrumentation or digital palpation.

Objective: To describe complications and outcomes of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors., Animals: 156 dogs undergoing unilateral thyroidectomy for a naturally occurring thyroid tumor., Procedures: Dogs that underwent a unilateral thyroidectomy in 2003 through 2015 were included in a multi-institutional retrospective study. For each dog, information gathered through evaluation of electronic and paper records included perioperative complications, short-term outcome (survival to discharge from the hospital vs nonsurvival), and long-term outcome (survival time)., Results: In the perioperative period, complications occurred in 31 of the 156 (19.9%) dogs; hemorrhage was the most common intraoperative complication (12 [7.7%] dogs). Five of 156 (3.2%) dogs received a blood transfusion; these 5 dogs were among the 12 dogs that had hemorrhage listed as an intraoperative complication. Immediately after surgery, the most common complication was aspiration pneumonia (5 [3.2%] dogs). One hundred fifty-three of 156 (98.1%) dogs that underwent unilateral thyroidectomy survived to discharge from the hospital. One hundred-thirteen dogs were lost to follow-up; from the available data, the median survival time was 911 days (95% confidence interval, 704 to 1,466 days)., Conclusions and Clinical Relevance: Results indicated that unilateral thyroidectomy in dogs with a naturally occurring thyroid tumor was associated with a perioperative mortality rate of 1.9% and a complication rate of 19.9% and that hemorrhage and aspiration pneumonia were the most common complications. Long-term survival of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors was not uncommon.

Objective: To compare complications and outcome following unilateral, staged bilateral, and single-stage bilateral ventral bulla osteotomy (VBO) in cats., Animals: 282 client-owned cats treated by VBO at 25 veterinary referral and academic hospitals from 2005 through 2016., Procedures: Medical records of cats were reviewed to collect information on signalment, clinical signs, diagnostic test results, surgical and postoperative management details, complications (anesthetic, surgical, and postoperative), and outcome. Associations were evaluated among selected variables., Results: Unilateral, staged bilateral, and single-stage bilateral VBO was performed in 211, 7, and 64 cats, respectively, representing 289 separate procedures. Eighteen (9%), 2 (29%), and 30 (47%) of these cats, respectively, had postoperative respiratory complications. Cats treated with single-stage bilateral VBO were significantly more likely to have severe respiratory complications and surgery-related death than cats treated with other VBO procedures. Overall, 68.2% (n = 197) of the 289 procedures were associated with Horner syndrome (19.4% permanently), 30.1% (87) with head tilt (22.1% permanently), 13.5% (39) with facial nerve paralysis (8.0% permanently), and 6.2% (18) with local disease recurrence. Cats with (vs without) Horner syndrome, head tilt, and facial nerve paralysis before VBO had 2.6, 3.3, and 5.6 times the odds, respectively, of having these conditions permanently., Conclusions and Clinical Relevance: Findings suggested that staged bilateral VBO should be recommended over single-stage bilateral VBO for cats with bilateral middle ear disease. Cats with Horner syndrome, head tilt, and facial nerve paralysis before surgery were more likely to have these conditions permanently following surgery than were cats without these conditions.

OBJECTIVE To assess for any association between a history of tibial plateau leveling osteotomy (TPLO) and subsequent development of proximal tibial osteosarcoma in dogs. DESIGN Matched case-control study. ANIMALS 34 client-owned dogs in which proximal tibial osteosarcoma was diagnosed between January 2005 and December 2012 (cases) and 79 dogs without osteosarcoma, matched 3:1 to cases (when possible) by age, breed, and initial examination date (controls). PROCEDURES Information on each case and control was collected from the medical records and other sources regarding date of birth, sex and neuter status, body weight, breed, and whether TPLO had been performed ≥ 1 year ago. A multivariable conditional logistic regression model was constructed to evaluate associations of body weight and history of TPLO with the outcome of proximal tibial osteosarcoma in dogs. RESULTS After adjusting for body weight in the multivariable model, dogs with a history of TPLO were 40 times as likely to develop proximal tibial osteosarcoma as were dogs with no history of TPLO. In addition, each 1-kg (2.2-lb) increase in body weight was associated with an 11% increase in the odds of proximal tibial osteosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dogs with a history of TPLO were at increased risk of developing osteosarcoma of the proximal region of the tibia relative to dogs with no such history. Therefore, it is important for proximal tibial osteosarcoma to be included among the differential diagnoses for new or worsening hind limb lameness in dogs that underwent TPLO ≥ 1 year previously.

OBJECTIVE To determine the most common types of injuries in cats surgically treated for thoracic trauma, complications associated with surgical treatment, and factors associated with mortality rate and evaluate the effectiveness of the animal trauma triage (ATT) scoring system for predicting outcome. DESIGN Retrospective case series with nested observational study. ANIMALS 23 client-owned cats surgically treated for thoracic trauma at 7 veterinary teaching hospitals between 1990 and 2014. PROCEDURES Medical records were reviewed to collect data on signalment, medical history, clinical signs and physical examination findings at initial evaluation, clinicopathologic findings, initial emergency treatments and diagnostic tests performed, type of trauma sustained, imaging findings, surgery details, postoperative complications, duration of hospitalization, and cause of death, if applicable. All variables were evaluated for associations with survival to hospital discharge. RESULTS Types of trauma that cats had sustained included dog bite or attack (n = 8 [35%]), motor vehicle accident (6 [26%]), other animal attack (2 [9%]), impalement injury or fall (2 [9%]), projectile penetrating trauma (1 [4%]), or unknown origin (4 [17%]). Intrathoracic surgery was required for 65% (15/23) of cats. The overall perioperative mortality rate was 13% (3/23). Mean ± SD ATT scores for surviving and nonsurviving cats were 6.4 ± 2.2 and 10.0 ± 1.7, respectively. Nineteen of 20 cats with no cardiopulmonary arrest survived to discharge, compared with 1 of 3 cats with cardiopulmonary arrest. Only these 2 variables were significantly associated with outcome. CONCLUSIONS AND CLINICAL RELEVANCE The perioperative mortality rate was low in this series of cats with thoracic trauma; however, those with cardiopulmonary arrest were less likely to survive to hospital discharge than other cats. Cats with a low ATT score were more likely to survive than cats with a high ATT score.

OBJECTIVE To determine perioperative mortality rate and identify risk factors associated with outcome in dogs with thoracic trauma that underwent surgical procedures and to evaluate the utility of the animal trauma triage (ATT) score in predicting outcome. DESIGN Retrospective case series. ANIMALS 157 client-owned dogs. PROCEDURES Medical records databases of 7 veterinary teaching hospitals were reviewed. Dogs were included if trauma to the thorax was documented and the patient underwent a surgical procedure. History, signalment, results of physical examination and preoperative laboratory tests, surgical procedure, perioperative complications, duration of hospital stay, and details of follow-up were recorded. Descriptive statistics and ATT scores were calculated, and logistic regression analysis was performed. RESULTS 123 of 157 (78%) patients underwent thoracic surgery, and 134 of 157 (85.4%) survived to discharge. Mean ± SD ATT score for nonsurvivors was 8 ± 2.4. In the multivariable model, female dogs and dogs that did not experience cardiac arrest as a postoperative complication had odds of survival 6 times and 102 times, respectively, those of male dogs and dogs that did experience cardiac arrest as a postoperative complication. Additionally, patients with a mean ATT score < 7 had odds of survival 5 times those of patients with an ATT score ≥ 7. CONCLUSIONS AND CLINICAL RELEVANCE The overall perioperative mortality rate was low for patients with thoracic trauma undergoing surgery in this study. However, male dogs and dogs that experienced cardiac arrest had a lower likelihood of survival to discharge. The ATT score may be a useful adjunct to assist clinical decision-making in veterinary patients with thoracic trauma.

OBJECTIVE To determine survival times of selected dogs with metastatic (stage III) osteosarcoma, whether disease-free interval (DFI) was associated with survival time after diagnosis of stage III disease (ie, stage III survival time), and whether a survival benefit of metastasectomy existed. DESIGN Retrospective case series with nested cohort study. ANIMALS 194 client-owned dogs treated for histologically confirmed appendicular osteosarcoma from 1997 through 2009. PROCEDURES Dogs were included if they had stage I or II osteosarcoma at the time of initial evaluation, had amputation of the affected appendage and ≥ 1 dose of chemotherapy afterward, and developed metastasis within the follow-up period or prior to death. Data collected from the medical records included signalment, primary tumor location, clinical and laboratory findings, whether metastasectomy was performed, and outcome. Various factors were examined for associations with outcome. RESULTS Dogs that received no treatment for the metastasis had a median survival time between 49 and 57 days after diagnosis of stage III osteosarcoma. Duration of the preceding DFI had no association with this period. Metastasectomy alone was associated with a longer median stage III survival time (232 days) than no metastasectomy (49 days). Among all dogs identified as qualifying for pulmonary metastasectomy on the basis of < 3 pulmonary nodules visible on thoracic radiographs and a DFI > 275 days (n = 21), a survival advantage was also identified for those that actually received pulmonary metastasectomy (6). CONCLUSIONS AND CLINICAL RELEVANCE Preceding DFI had no influence on survival time of dogs with stage III osteosarcoma. Metastasectomy was associated with an increase in survival time for selected dogs.

OBJECTIVE To compare clinical signs, laboratory test results, and imaging findings between dogs with suspected anaphylaxis and dogs with sepsis. DESIGN Retrospective case-case study. ANIMALS 10 dogs with suspected anaphylaxis and 22 dogs with confirmed sepsis that met the criteria for systemic inflammatory response syndrome. PROCEDURES Medical records for dogs in each group were reviewed and data extracted regarding signalment; reason for hospital admission; physical examination findings; results of CBC, serum biochemical analysis, coagulation testing, cytologic examination, and microbial culture; and imaging reports. RESULTS All dogs in the anaphylaxis group fulfilled the criteria for systemic inflammatory response syndrome. Dogs in both groups had gastrointestinal signs, lethargy, mentation change, and bleeding abnormalities. Dogs with suspected anaphylaxis had a significantly higher eosinophil count and serum alanine aminotransferase activity and lower blood pH than dogs with sepsis. Dogs with sepsis had a significantly higher band neutrophil count, serum globulins concentration, and serum alkaline phosphatase activity and lower serum glucose concentration. Dogs in both groups had intracavitary free fluid and ultrasonographic findings of thickened intestines, gas or fluid-filled intestines, and a thickened gallbladder wall. CONCLUSIONS AND CLINICAL RELEVANCE Clinical signs, laboratory values, and imaging findings may be similar in dogs with sepsis or anaphylaxis. Given the marked difference in prognosis and treatment, early differentiation is important. Anaphylaxis should be considered if a septic nidus cannot be identified, and supportive care should be considered for such patients.

OBJECTIVE To evaluate colonoscopic and histologic features of rectal masses in dogs. DESIGN Retrospective case series. ANIMALS 82 client-owned dogs with rectal masses that underwent colonoscopy. PROCEDURES Medical records of dogs with rectal masses that underwent colonoscopy were reviewed. History, signalment, clinical signs, results of physical examination, diagnostic imaging findings, and results of colonoscopy (including complications) were recorded. When available, tissue samples obtained during colonoscopy and by means of surgical biopsy were reviewed by a single board-certified pathologist. Histologic features and tumor grade (when applicable) of tissue samples obtained during colonoscopy versus surgical biopsy were compared. RESULTS Multiple rectal masses were observed during colonoscopy in 6 of the 82 dogs, but no lesions were visualized orad to the colorectal junction. Results of histologic evaluation of surgical biopsy specimens were consistent with a diagnosis of epithelial neoplasia in 58 of 64 dogs, of which 71% were classified as benign adenoma or polyp and 29% were classified as adenocarcinoma in situ or adenocarcinoma. Complications of colonoscopy occurred in 3 of 82 dogs but were considered minor. A discrepancy in diagnosis occurred in 5 of 16 dogs for which both colonoscopic and surgical biopsy samples were available for histologic review. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that multiple rectal masses are uncommon in dogs, and secondary lesions orad to the colorectal junction were not found in this study. Colonoscopy was associated with few complications, but the need for colonoscopic assessment of the entire colon in this patient population may merit reevaluation.

OBJECTIVE To evaluate perioperative morbidity and outcome in dogs and cats undergoing esophageal surgery. DESIGN Retrospective case series. ANIMALS 63 client-owned dogs and 9 client-owned cats. PROCEDURES Medical records of dogs and cats that underwent esophageal surgery were reviewed for information on signalment, history, results of preoperative diagnostic testing, condition treated, details of surgery, intraoperative complications, and postoperative complications. Long-term follow-up data were obtained via veterinarian and client telephone conversations. The relationship between complications and survival to hospital discharge was evaluated by means of regression analysis. RESULTS The most common indication for surgical intervention was an esophageal foreign body in dogs (50/63 [79%]) and esophageal stricture in cats (3/9). Complications were documented in 54% (34/63) of dogs and 3 of 9 cats. The most common immediate postoperative complications were respiratory in nature (9 dogs, 1 cat). Partial esophagectomy and resection with anastomosis were significantly associated with the development of immediate postoperative complications in dogs. The most common delayed postoperative complications were persistent regurgitation (7 dogs) and esophageal stricture formation (3 dogs, 1 cat). For dogs, a mass lesion and increasing lesion size were significantly associated with the development of delayed postoperative complications. Six dogs (10%) and 1 cat died or were euthanized prior to discharge, and pneumomediastinum and leukopenia were negative prognostic factors for dogs being discharged from the hospital. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study suggested that the short-term prognosis for dogs and cats that survive surgery for treatment of esophageal lesions is favorable, with 90% of patients discharged from the hospital (57/63 dogs; 8/9 cats). However, dogs treated for more extensive esophageal lesions as well as those undergoing esophagectomy or resection and anastomosis were more likely to develop postoperative complications.

OBJECTIVE To evaluate effects of anatomic location, histologic processing, and sample size on shrinkage of excised canine skin samples. SAMPLE Skin samples from 15 canine cadavers. PROCEDURES Elliptical samples of the skin, underlying subcutaneous fat, and muscle fascia were collected from the head, hind limb, and lumbar region of each cadaver. Two samples (10 mm and 30 mm) were collected at each anatomic location of each cadaver (one from the left side and the other from the right side). Measurements of length, width, depth, and surface area were collected prior to excision (P1) and after fixation in neutral-buffered 10% formalin for 24 to 48 hours (P2). Length and width were also measured after histologic processing (P3). RESULTS Length and width decreased significantly at all anatomic locations and for both sample sizes at each processing stage. Hind limb samples had the greatest decrease in length, compared with results for samples obtained from other locations, across all processing stages for both sample sizes. The 30-mm samples had a greater percentage change in length and width between P1 and P2 than did the 10-mm samples. Histologic processing (P2 to P3) had a greater effect on the percentage shrinkage of 10-mm samples. For all locations and both sample sizes, percentage change between P1 and P3 ranged from 24.0% to 37.7% for length and 18.0% to 22.8% for width. CONCLUSIONS AND CLINICAL RELEVANCE Histologic processing, anatomic location, and sample size affected the degree of shrinkage of a canine skin sample from excision to histologic assessment.

Objective: To identify risk factors for urolithiasis in dogs with congenital extrahepatic portosystemic shunts (EHPSSs) and to determine whether portoazygos shunts were associated with increased risk of urolithiasis at the initial evaluation for EHPSS., Design: Retrospective case series., Animals: Dogs (n = 95) with EHPSSs confirmed via CT angiography or surgery., Procedures: Medical records from 1999 to 2013 were reviewed. Variables of interest included signalment, previous medical management, and results of urinalysis, urolith analyses, and diagnostic imaging. Univariable and multivariable logistic regression analyses for assessment of risk factors for urolithiasis at the time of initial EHPSS evaluation were performed., Results: The dogs' median age was 0.9 years (range, 0.2 to 12.6 years). Among the 95 dogs, 27 (28.4%) and 68 (71.6%) had portoazygos and portocaval shunts, respectively. Urinalysis was performed for 79 (83.2%) dogs, 29 (36.7%) of which had crystalluria (mainly ammonium urate and struvite crystals). Uroliths were present in 34 of 95 (35.8%) dogs; 16 of 17 uroliths analyzed were composed of ammonium urate. Portoazygos shunts were not associated with significantly increased odds of urolithiasis at the time of the initial evaluation for EHPSS. However, the odds of urolithiasis was significantly increased for male dogs, older dogs, and dogs that received previous medical treatment., Conclusions and Clinical Relevance: In dogs with EHPSS, shunt morphology was not associated with increased odds of urolithiasis at the initial evaluation. Male dogs, older dogs, and dogs having received medical management for EHPSS prior to initial evaluation should be considered at increased risk for development of urolithiasis.

Objective: To evaluate the outcome in terms of progression-free interval (PFI) and overall survival time (ST) after curative-intent resection of oral melanoma in dogs., Design: Retrospective case series., Animals: 70 client-owned dogs., Procedures: An electronic medical record search and review was performed for dogs that underwent curative-intent resection of oral melanoma (May 1, 1998, to December 31, 2011). Information gathered included signalment, oral location of tumor, staging results, type of surgery, type of adjuvant therapy, findings on histologic evaluation, and outcome., Results: 36 (51.4%), 16 (22.9%), 13 (18.6%), and 1 (1.4%) of 70 dogs had tumors classified as stage I, II, III, and IV, respectively; tumor stage could not be determined for 4 (5.7%) dogs because of the lack of tumor size information. Fifty-one (72.9%) dogs had tumors completely excised. Twenty-nine (41.4%) dogs received adjuvant therapy. Median PFI and ST were 508 and 723 days, respectively. Thirty-two (45.7%) dogs had disease progression. Significant associations with PFI or ST were found for administration of adjuvant therapy, presence of metastatic disease at the time of diagnosis, higher tumor stage (III or IV), increased tumor size (> 3 cm), and sexually intact female dogs. Administration of adjuvant treatment was associated with a 130% increased hazard (hazard ratio, 2.3; 95% confidence interval [CI], 1.0 to 5.0) of disease progression; the presence of metastases at the time of diagnosis was associated with a 281% increased hazard (hazard ratio, 3.8; 95% CI, 1.5 to 9.6) of death., Conclusions and Clinical Relevance: Results indicated that dogs with oral melanoma can have a long PFI and ST after resection with wide margins.

Objective: To describe the biological behavior, clinical outcome, and prognostic factors of osteosarcoma of the maxilla, mandible, or calvarium in dogs., Design: Retrospective case series., Animals: 183 client-owned dogs with osteosarcoma of the maxilla, mandible, or calvarium., Procedures: Medical records for dogs treated for osteosarcoma of the maxilla, mandible, or calvarium from 1986 through 2012 were reviewed. Dogs with a histopathologic diagnosis of osteosarcoma and treated for a primary tumor arising from these bones of the head were included., Results: Mean age was 9.3 years, and body weight was 31.8 kg (70.0 lb). Most dogs (124/183 [67.8%]) were purebred, and the most common primary tumor site was the maxilla (80 [43.7%]). Treatments included palliative medical treatment only (11/183 [6.0%]), coarsely fractionated radiation therapy (RT; 12 [6.6%]), fractionated or stereotactic RT (18 [9.8%]), surgery (135 [73.8%]), and both surgery and fractionated RT (7 [3.8%]). Eighty-three (45.4%) dogs received adjuvant chemotherapy. Local recurrence or progression occurred in 80 of 156 (51.3%) dogs, and 60 of 156 (38.5%) dogs developed distant metastases. Median survival time for all dogs was 239 days. Dogs that underwent surgery had a median survival time of 329 days. Histologically tumor-free surgical margins were associated with significantly decreased hazards of progression or recurrence (hazard ratio [HR], 0.4) and death (HR, 0.5). Dogs with osteosarcoma of the calvarium had a significantly greater hazard of local recurrence or progression (HR, 2.0)., Conclusions and Clinical Relevance: In this study, tumor excision in dogs with histologically tumor-free margins resulted in better local control and longer survival time than did other treatment types.

Objective: To evaluate the incidence of and factors associated with complications following rectal pull-through (RPT) surgery and the outcome for dogs with rectal tumors., Design: Retrospective case series., Animals: 74 dogs with rectal masses., Procedures: Information regarding signalment, history, diagnostic testing, type of rectal disease, surgical details, and postoperative complications, treatments, and outcomes was obtained from medical records and follow-up communications. Survival times were calculated. Descriptive statistics were generated. Regression analyses were used to evaluate the effect of various variables on the development of postsurgical complications and survival time., Results: 58 (78.4%) dogs developed postsurgical complications, the most common of which was fecal incontinence with 42 (56.8%) dogs affected, of which 23 (54.8%) developed permanent incontinence. Other complications included diarrhea (n = 32), tenesmus (23), stricture formation (16), rectal bleeding (8), constipation (7), dehiscence (6), and infection (4). The rectal tumor recurred in 10 dogs. The median survival time was 1,150 days for all dogs and 726 days for dogs with malignant tumors. The 2 most common rectal masses were rectal carcinoma and rectal carcinoma in situ, and the dogs with these tumors had median survival times of 696 and 1,006 days, respectively., Conclusions and Clinical Relevance: Dogs with rectal diseases that underwent RPT surgery had a high incidence of complications; however, those dogs had good local tumor control and survival times. The risk and impact of postsurgical complications on the quality of life and oncological outcomes should be discussed with owners before RPT surgery is performed in dogs with rectal masses.

Objective: To describe outcomes for small-breed dogs with appendicular osteosarcoma., Design: Multi-institutional retrospective case series., Animals: 51 small-breed dogs., Procedures: Records from participating Veterinary Society of Surgical Oncology members were searched for dogs that weighed ≤ 15 kg (33 lb) with a histologic diagnosis of appendicular osteosarcoma. The Kaplan-Meier method was used to determine median survival times (MSTs), and Cox regression was performed to identify variables associated with survival time., Results: Tumors were most commonly located on the humerus (n = 15) and femur (14). Of the 51 study dogs, 9 were treated nonsurgically, 16 underwent amputation of the affected limb only, and 26 underwent curative-intent treatment, with MSTs of 112, 257, and 415 days, respectively. The MST did not differ significantly between dogs in the amputation-only and curative-intent groups. For dogs in the nonsurgical group, MST decreased significantly as the tumor histologic score increased. For dogs in the amputation-only group, MST decreased as body weight increased., Conclusions and Clinical Relevance: For the small-breed dogs with appendicular osteosarcoma of the present study, tumor histologic grade and mitotic index were subjectively lower and MST following amputation of the affected limb without adjuvant chemotherapy was longer, compared with those for similarly affected larger dogs. Results indicated no significant advantage in MST for dogs that underwent curative-intent treatment versus dogs that underwent amputation only, and further investigation of the importance of adjuvant chemotherapy is warranted.

Objective: To determine the signalment, tibial plateau leveling osteotomy (TPLO) plate type, clinical staging information, treatment, and oncological outcome in dogs that developed osteosarcoma at the proximal aspect of the tibia following TPLO and to calculate the interval between TPLO and osteosarcoma diagnosis., Design: Multi-institutional retrospective case series., Animals: 29 dogs., Procedures: Medical records from 8 participating institutions were searched for dogs that developed osteosarcoma (confirmed through cytologic or histologic evaluation) at previous TPLO sites. Signalment, TPLO details, staging tests, treatment data, and outcome information were recorded. Descriptive statistics were calculated, and disease-free intervals and survival times were evaluated by means of Kaplan-Meier analysis., Results: 29 dogs met the inclusion criteria. The mean age was 9.2 years and mean weight was 45.1 kg (99.2 lb) at the time of osteosarcoma diagnosis. Most dogs had swelling over the proximal aspect of the tibia (17/21) and lameness of the affected limb (28/29). The mean interval between TPLO and osteosarcoma diagnosis was 5.3 years. One type of cast stainless steel TPLO plate was used in most (18) dogs; the remaining dogs had received plates of wrought stainless steel (n = 4) or unrecorded type (7). Twenty-three of 29 dogs underwent treatment for osteosarcoma. Median survival time for 10 dogs that underwent amputation of the affected limb and received ≥ 1 chemotherapeutic treatment was 313 days., Conclusions and Clinical Relevance: Results supported that osteosarcoma should be a differential diagnosis for dogs with a history of TPLO that later develop lameness and swelling at the previous surgical site. Oncological outcome following amputation and chemotherapy appeared to be similar to outcomes previously reported for dogs with appendicular osteosarcoma.