Surgery and postoperative definitive radiotherapy for management of canine soft tissue sarcoma: a multi-institutional retrospective study of 272 dogs (2010-2020).

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.

Prospective assessment of canine thyroid cancer-part I: nodal metastatic rate and impact of nodal immunohistochemistry in 70 dogs.

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.

Retrospective evaluation of the prevalence and risk factors associated with red blood cell transfusions in cats with urethral obstruction (2009-2019): 575 cases.

OBJECTIVE: To evaluate the prevalence of red blood cell (RBC) transfusions and factors associated with the need for transfusion in cases of feline urethral obstruction (FUO). Secondarily, to compare survival to discharge in cats receiving an RBC transfusion versus those that did not. DESIGN: Retrospective, multi-institutional study from 2009 to 2019. SETTING: Four university teaching hospitals. ANIMALS: Six hundred twenty-two total occurrences of FUO in 575 cats. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were retrospectively reviewed for pertinent information. The overall prevalence of severe anemia (PCV < 0.20 L/L [<20%]) at presentation was 1.0% (6/622). The prevalence of RBC transfusions during hospitalization was 2.1% (13/622). Cats that received an RBC transfusion weighed significantly less than those that did not (4.9 vs 5.8 kg; P = 0.034) and had a lower PCV at presentation (0.30 L/L [30%] vs 0.41 L/L [41%]; P < 0.001). Hospitalization time (240 vs 72 h) and indwelling urinary catheter time (168 vs 48 h) were significantly longer in cats receiving a transfusion compared with those that did not (P < 0.001). Creatinine concentrations were not significantly associated with transfusion administration, while BUN was higher in cats receiving a transfusion (15.35 mmol/L [43 mg/dL] vs. 11.78 mmol/L [33 mg/dL]; P = 0.043). Transfusion rates were significantly higher in cats undergoing perineal urethrostomy (5.5%) compared with those that did not undergo surgery (0.97%; P < 0.001). The overall survival to discharge rate was 96%. Cats not receiving an RBC transfusion were significantly more likely to survive to discharge than those that did (odds ratio: 14.7, 95% confidence interval: 1.8-37; P < 0.001). CONCLUSIONS: FUO is rarely associated with severe anemia and the need for RBC transfusions. In this study, cats receiving an RBC transfusion were less likely to survive to discharge; therefore, requiring a blood transfusion may be associated with a worse prognosis. In addition, the need for surgical intervention was associated with a higher prevalence of RBC transfusions.

Sodium iodide symporter immunolabelling as a predictor of clinical iodide uptake in canine thyroid carcinoma: A preliminary study.

Thyroid follicular tumours may take up iodide via the sodium-iodide symporter. Knowledge of iodide uptake could then allow treatment with I-131 in dogs with high-risk tumours. The objective of this study was to determine the relationship between clinically detectable iodide uptake (as determined by scintigraphy and/or thyroxine concentrations) and sodium iodide symporter immunohistochemical labelling on histologically fixed thyroid tumours. Nineteen dogs were identified who were diagnosed with thyroid carcinoma and underwent surgery from November 2017 to July 2021. All had recorded thyroid hormone concentrations and were hyperthyroid and/or underwent preoperative nuclear imaging using planar scintigraphy (technetium-99m or I-123), or I-124 PET-CT. All dogs subsequently underwent surgery to remove the thyroid mass. Twenty-two tumours were submitted for histopathologic analysis immediately following surgery, which confirmed a diagnosis of thyroid carcinoma for each tumour. Images and/or thyroid hormone concentrations were reviewed for the included cases, and tumours were sorted into an avid/functional group (group 1) and a non-avid/functional group (group 2). The tumour tissues were re-examined histologically using sodium iodide symporter (NIS) immunohistochemistry (IHC). Group 1 contained 15 avid/functional tumours. Twelve of these tumours had membranous NIS IHC labelling. Group 2 contained 7 non-avid tumours. One of these tumours had membranous NIS IHC labelling. This resulted in an overall sensitivity and specificity for identification of avid/functional tumours with membranous NIS of 80.0% and 85.7%, respectively. NIS IHC may predict ion trapping in canine follicular thyroid tumours. Further studies using iodide-based imaging are warranted to better determine the clinical utility of this diagnostic modality.

Fascial plane mapping for superficial tumor resection in dogs. Part III: Hindlimb and pelvis.

OBJECTIVES: To categorize the fascial planes and the intersections of these fascial planes in the hindlimb of the dog to facilitate preoperative planning for superficial cancers. STUDY DESIGN: Qualitative anatomical study. SAMPLE POPULATION: Four male and five female mixed breed dogs, weighing ~15-35 kg. METHODS: Skin and subcutaneous fat were removed, and fascial planes were explored to determine borders and quality. Fascia was categorized as type I (discrete sheets), type II (adhered to thin muscles), type III (adhered to thick muscles), or type IV (associated with periosteum). Digital modification of specimen photographs was performed to map tissues. RESULTS: Differences in dogs were noted due to either size or sex but were sufficiently minor to allow mapping. Fasciae of the hindlimb were predominantly type II or III, with type I fascia primarily at the lateral gluteal region, fascia lata, and lateral crus. Type IV fascia was seen at the iliac wing, ischium, patella, tibial tuberosity, medial tibia, distal crus, and pes. Fascia for surgical use was thin or absent at the ischiorectal fossa, femoral triangle, extensor mechanism, medial and distal crus, and pes. Intersections and tissues at the ventral perineum may also pose challenges for maintenance of a deep margin. CONCLUSION: Fascial types and integrity of the hindlimb varied with location, with the perineum, cranial stifle, and distal limb presenting the greatest challenges. CLINICAL SIGNIFICANCE: These images may be used to guide both therapeutic decision-making and intraoperative excision of superficial tumors of the hindlimb and pelvis.

Buccal transposition flap for closure of maxillary lip defects in 5 dogs.

OBJECTIVE: To describe the technique and outcomes of the closure of maxillary lip defects using a buccal transposition flap and to identify potential routes of vascular supply to the flap. ANIMALS: Five dogs treated clinically and 1 cadaveric dog head. STUDY DESIGN: Short case series and cadaveric study. METHODS: A left maxillary labial defect and a buccal transposition flap were created on a cadaver head. Iodinated contrast was injected into the left common carotid artery and computed tomography was performed to assess the vascular supply. Medical records were reviewed for all dogs that underwent tumor excision with maxillary lip resection, reconstructed with a buccal transposition flap. RESULTS: The buccal transposition flap was perfused by branches of the angularis oris artery and superior labial artery. Five dogs were included in this study. All flaps survived. Three dogs developed postoperative complications, including oronasal fistula (n = 2) and partial flap dehiscence (n = 1). The cosmetic and functional outcomes were considered satisfactory in all cases. CONCLUSION: Buccal transposition flaps for the closure of large maxillary lip defects provided adequate functional and cosmetic outcomes. The buccal transposition flap had vascular contributions from the angularis oris artery and the superior labial artery.

Axillary lymphadenectomy in dogs: A description of surgical technique.

The axillary lymph center drains a large area; however, axillary lymphadenectomy is rarely reported in series detailing lymph node extirpation in dogs. No surgical technique has yet been described for axillary and superficial axillary lymphadenectomy. This study describes a technique for excision of nodes in the axillary lymph center of the dog. Two male neutered and two male intact cadavers weighing between 6.3 and 36.1 kg were used. With cadavers in dorsal recumbency and the shoulder extended, an incision was made in the caudal axillary region. Blunt dissection was used to separate the pectoralis profundus and latissimus dorsi muscles and loose connective tissue was dissected until the axillary lymph node was identified caudal to the brachial vein. The axillary lymphatic trunk was followed caudad from the axillary lymph node to identify the accessory axillary lymph node, deep to the lateral border of the pectoralis profundus muscle, for subsequent extirpation. Axillary lymph nodes were successfully removed in all axillae, and accessory axillary lymph nodes were located in 6/7 axillae and could not be visualized within the axillary lymphatic trunk in the remaining axilla. The described surgical technique allowed consistent identification of the axillary lymph node and the lymphatic trunk associated with the accessory axillary lymph node. This technique description provides a guide for surgeons to facilitate axillary and accessory axillary lymphadenectomy in the dog. While anatomic variation must be considered, the use of the axillary lymphatic trunk as a landmark may simplify identification of the small and inconsistent accessory axillary lymph node.

Fascial plane mapping for superficial tumor resection in dogs. Part II: Forelimb.

OBJECTIVE: To detail the qualitative fascial categories and fascial intersections of the forelimb of the dog to facilitate preoperative planning for superficial cancers. STUDY DESIGN: Qualitative anatomical study. SAMPLE POPULATION: Three male and four female mixed breed canine cadavers weighing approximately 20-35 kg. METHODS: The skin and subcutaneous fat were excised. Fascial planes were incised and elevated to allow exploration of their quality and borders. Fascia was categorized as type I (discrete sheets), type II (tightly adhered to thin muscles), type III (tightly adhered to thick muscles), or type IV (associated with periosteum). Photographs of specimens were digitally modified with overlays to map tissue types. RESULTS: Differences between the cadavers used were largely based on muscle mass and sex, with minimal other subjective differences affecting fascial mapping. The fasciae of the forelimb were largely type II or type III, with type I fascia at the antebrachium and type IV fascia at the olecranon, scapular spine, and accessory carpal bone. Fascial integrity was often questionable or lacking distal to the distal quarter of the antebrachium. CONCLUSION: The fascial types and integrity of the forelimb varied with anatomic location with thin or absent fascia for surgical use at the elbow, carpus, and manus. CLINICAL SIGNIFICANCE: This study provides information for preoperative planning and excision of superficial tumors of the forelimb. Knowledge of the potential limitations of fascia to provide a deep margin may influence selection of treatment modalities.

Incidence, survival time, and surgical treatment of parathyroid carcinomas in dogs: 100 cases (2010-2019).

OBJECTIVE: To evaluate outcomes of dogs with parathyroid carcinoma (PTC) treated by surgical excision and to describe the incidence of postoperative hypocalcemia, degree of hypocalcemia, duration of hospitalization, duration of calcium supplementation, and survival time. ANIMALS: 100 client-owned dogs with PTC admitted to academic, referral veterinary institutions. PROCEDURES: In a retrospective multi-institutional study, medical records of dogs undergoing surgical excision of PTC between 2010 to 2019 were reviewed. Signalment, relevant medical history, clinical signs, clinicopathologic testing, imaging, surgical findings, intraoperative complications, histologic examination, and survival time were recorded. RESULTS: 100 dogs with PTC were included, and 96 dogs had clinical or incidental hypercalcemia. Common clinical signs included polyuria (44%), polydipsia (43%), hind limb paresis (22%), lethargy (21%), and hyporexia (20%). Cervical ultrasonography detected a parathyroid nodule in 91 of 91 dogs, with a single nodule in 70.3% (64/91), 2 nodules in 25.3% (23/91), and ≥ 3 nodules in 4 (4/91)% of dogs. Hypercalcemia resolved in 89 of 96 dogs within 7 days after surgery. Thirty-four percent of dogs developed hypocalcemia, on the basis of individual analyzer ranges, within 1 week after surgery. One dog had metastatic PTC to the prescapular lymph node, and 3 dogs were euthanized for refractory postoperative hypocalcemia. Estimated 1-, 2-, and 3-year survival rates were 84%, 65%, and 51% respectively, with a median survival time of 2 years. CONCLUSIONS AND CLINICAL RELEVANCE: Excision of PTC results in resolution of hypercalcemia and excellent long-term tumor control. Surgical excision of PTC is recommended because of resolution of hypercalcemia and a good long-term prognosis. Future prospective studies and long-term follow-up are needed to further assess primary tumor recurrence, metastasis, and incidence of postoperative hypocalcemia.

Management of severe burn injuries with novel treatment techniques including maggot debridement and applications of acellular fish skin grafts and autologous skin cell suspension in a dog.

CASE DESCRIPTION: A 3-year-old 27-kg female spayed American Bulldog with severe burn injuries caused by a gasoline can explosion was evaluated. CLINICAL FINDINGS: The dog had extensive partial- and full-thickness burns with 50% of total body surface area affected. The burns involved the dorsum extending from the tail to approximately the 10th thoracic vertebra, left pelvic limb (involving 360° burns from the hip region to the tarsus), inguinal area bilaterally, right medial aspect of the thigh, and entire perineal region. Additional burns affected the margins of the pinnae and periocular regions, with severe corneal involvement bilaterally. TREATMENT AND OUTCOME: The dog was hospitalized in the hospital's intensive care unit for 78 days. Case management involved provision of aggressive multimodal analgesia, systemic support, and a combination of novel debridement and reconstructive techniques. Debridement was facilitated by traditional surgical techniques in combination with maggot treatment. Reconstructive surgeries involved 6 staged procedures along with the use of novel treatments including applications of widespread acellular fish (cod) skin graft and autologous skin cell suspension. CLINICAL RELEVANCE: The outcome for the dog of the present report highlighted the successful use of maggot treatment and applications of acellular cod skin and autologous skin cell suspension along with aggressive systemic management and long-term multimodal analgesia with debridement and wound reconstruction for management of severe burn injuries encompassing 50% of an animal's total body surface area.

Outcome and postoperative complications in 73 dogs with thyroid carcinoma with gross vascular invasion managed with thyroidectomy.

Excellent outcomes have been reported following thyroidectomy for thyroid carcinoma in dogs, but outcomes for thyroid carcinomas with gross vascular invasion are poorly described. This study describes the clinical outcomes and complications in dogs with thyroid carcinomas with gross vascular invasion undergoing thyroidectomy. Medical records of dogs that underwent thyroidectomy between January 1st 2010 and December 31st 2019 were reviewed at 10 hospitals. Signalment, diagnostic data, primary and adjuvant treatments performed, and outcome were abstracted. Survival was calculated using Kaplan-Meier analysis. Multiple logistic regression was used to identify variables associated with disease-specific survival. Seventy-three dogs were included, of which 58 underwent unilateral thyroidectomy and 15 underwent bilateral thyroidectomy. Complications were reported in five dogs (three major, two minor; 6.8%) intraoperatively and 12 dogs (two major leading to death, 10 minor; 16.4%) postoperatively. Seven (9.6%) dogs developed locoregional recurrence at a median of 238 days postoperatively (range: 15-730 days). Distant metastasis was suspected or confirmed in nine dogs (12.3%) at a median of 375 days postoperatively (range: 50-890 days). Twenty-seven dogs (37%) received adjuvant therapy (chemotherapy: n = 21; radiotherapy: n = 6). Thirty-nine dogs were euthanized or died, with 20 deaths related to disease (n = 10) or of unknown cause (n = 10), 19 due to unrelated causes, and nine lost to follow-up. Median overall and disease-specific survival were 621 days and not reached respectively. One-year disease-specific survival rate was 82.5%. No variables were associated with disease-specific survival in our dataset. Surgery may be considered for loco-regional therapy in dogs with thyroid carcinoma with gross vascular invasion.

Evaluation of a microvascular anastomotic coupler for end-to-side arterial and venous anastomosis for feline renal transplantation.

OBJECTIVE: To describe the technique and determine the feasibility of an end-to-side (ETS) anastomosis of the renal vein to vena cava and renal artery to aorta using a microvascular anastomotic coupler (MAC) for feline renal transplantation. STUDY DESIGN: In vivo experimental study. ANIMALS: Six purpose-bred domestic shorthair cats. METHODS: The left kidney was autotransplanted using a MAC for ETS vascular anastomosis. Outcomes included intraoperative hemorrhage from the anastomosis sites, duration of anastomoses, surgical complications, postoperative renal perfusion (including resistive index (RI)) measured by Doppler ultrasonography and computed tomography angiography, and histopathological examination of the left kidney and anastomosis sites (30 days). RESULTS: Anastomosis was successful in all cats, and intraoperative hemorrhage was negligible. Intraoperative renal perfusion was considered excellent. Venous and arterial anastomoses were completed in 11 minutes 20 seconds (range, 6:38-13:27) and 21 minutes 50 seconds (range, 11:05-30:24), respectively. Vascular occlusion time was 32 minutes (17:43-42:03). One cat was euthanized 5 hours postoperatively because of bleeding from a muscular arterial branch of the dorsal aorta causing hemoabdomen. Renal perfusion and RI of the remaining five cats were within normal range (<0.8) and similar to the contralateral kidney at all time points. Endothelialization of the anastomosis was complete with mild-to-moderate fibrosis surrounding the MAC in all cats. CONCLUSION: End-to-side anastomosis of the renal vein and artery to the vena cava and aorta, respectively, was consistently achieved in all six cats with the MAC. CLINICAL SIGNIFICANCE: The use of the MAC may be considered as an alternative to hand suturing for ETS anastomoses for feline renal transplantation.

Canine tonsillar neoplasia and tonsillar metastasis from various primary neoplasms.

Tonsillar metastasis from distant primary tumours has not been described in dogs, and reports are rare in humans. The aims of this study were to determine whether tumour metastasis occurs to the canine palatine tonsils and evaluate whether afferent lymphatics drain to the palatine tonsils via skull indirect computed tomography lymphangiography (ICTL). Retrospective review of the diagnostic laboratory tonsillar histopathology submissions was performed. ICTL studies (n = 53) were retrospectively reviewed by a single radiologist. Of 882 total tonsil histopathology samples, 492 (56%) were considered neoplastic, with 8% of them benign. Of the primary malignant neoplasms of the tonsil, squamous cell carcinoma (55%), lymphoma (17%) and melanoma (12%) were most common. Tonsillar metastasis was confirmed in 41 cases; histopathologic evaluation revealed melanoma (25), carcinoma (10), hemangiosarcoma (2) and one each of fibrosarcoma, malignant histiocytosis, basal cell tumour and undifferentiated sarcoma. A total of 53 tonsillar melanoma cases were identified, of which 25 represented metastasis from a known distant primary tumour and 28 were solely tonsillar, with 9 of these cases having concurrent lymph node metastasis. No ICTL cases had lymphatic contrast drainage to the palatine tonsil. The palatine tonsil is an important site of metastasis for a variety of primary tumour types from many locations. ICTL did not reveal lymphatics draining to the palatine tonsil, which is highly supportive of hematogenous route of metastasis to the tonsil. Tonsillar metastasis may be more common than previously thought. It is recommended to perform a thorough oral examination, including the tonsils, for all oral tumours and melanoma cases.

Adherence to follow-up recommendations for dogs with apocrine gland anal sac adenocarcinoma: A multicentre retrospective study.

Progressive disease is common following anal sacculectomy for apocrine gland anal sac adenocarcinoma (AGASACA); additional therapy may prolong survival. Adherence to medical recommendations influences therapeutic success in humans. The purpose of this study was to assess the adherence to follow-up recommendations in dogs with AGASACA. Medical records of patients that underwent anal sacculectomy for AGASACA, with or without iliosacral lymphadenectomy, between July 2015 and July 2018, were reviewed at eight referral institutions to assess post-operative recommendations and owner adherence to recommendations. One hundred and seventy-four dogs were included, of which 162 underwent unilateral anal sacculectomy, 12 underwent bilateral anal sacculectomy and 39 underwent concurrent iliosacral lymphadenectomy. Seventy-six owners (44%) received recommendations for staging at the time of discharge, histopathology results or at the first follow-up visit. One hundred and forty owners (80%) received recommendations for treatment following the initial surgery. Fifty of seventy-six (66%) owners pursued at least one staging recommendation and 69 of 140 (49%) owners pursued some kind of adjuvant treatment recommendation. Overall, 16 of 76 (21%) were adherent to staging recommendations with 20 adherent for the first year following surgery (26%). Forty-seven of 140 (34%) were adherent to treatment recommendations with 54 (39%) adherent for the first year. Owners that were adherent to restaging recommendations at 1 year following surgery were significantly more likely to pursue treatment for progressive disease (P = .014). Further work is required to assess owner motivation and evaluate strategies to improve adherence, given the potential impact on patient treatment.

Bilateral caudal maxillectomy for resection of tumors crossing palatal midline and use of the angularis oris axial pattern flap for primary closure or dehiscence repair in two dogs.

OBJECTIVE: To describe the technique and outcomes for bilateral caudal maxillectomy for resection of large caudal maxillary tumors crossing palatal midline in two dogs. STUDY DESIGN: Clinical case report. ANIMALS: Two client-owned dogs. METHODS: Two client-owned dogs with primary caudal maxillary tumors, a poorly differentiated sarcoma, and a multilobulated osteochondrosarcoma. Bilateral caudal maxillectomies were performed for curative-intent resection of these tumors. The angularis oris axial pattern flap was used for primary closure in one dog and for dehiscence repair in the other. RESULTS: Both tumors were resected with complete histologic margins. The defects were closed with local buccal mucosal flaps, with or without a unilateral angularis oris flap. Esophagostomy tubes were placed at time of surgery to bypass oral feeding. Incisional dehiscence and subsequent oronasal fistula formation occurred as a postoperative complication in both dogs (3 and 10 days, respectively). Both were successfully repaired with a combination of local buccal mucosal flaps and the angularis oris flap. Both dogs had good functional outcome and quality of life after recovery from revision surgery. CONCLUSION: Bilateral caudal maxillectomy allowed resection of caudal maxillary tumors crossing palatal midline, with good function and quality of life after recovery in 2 dogs. CLINICAL SIGNIFICANCE: Good outcomes including complete resections are achievable with bilateral caudal maxillectomy despite complications. Local mucosal and axial pattern flaps can be used for dehiscence repair.

Urethral diverticulum and urolithiasis in a female guinea pig (Cavia porcellus).

CASE DESCRIPTION A 5-year-old sexually intact female guinea pig was evaluated because of mild dysuria and a subcutaneous mass located cranioventral to the urogenital openings. CLINICAL FINDINGS Non-contrast-enhanced CT and surgical exploration of the distal aspect of the urethra revealed a urethral diverticulum with an intraluminal urolith. Analysis revealed that the urolith was composed of calcium carbonate and struvite. TREATMENT AND OUTCOME The urolith was surgically removed and ablation of the urethral diverticulum was attempted. Approximately 3 months later, the guinea pig was reevaluated for masses in the perineal region, and positive-contrast urethrocystography revealed 2 uroliths present in the same diverticulum. Uroliths were manually expressed with the patient under general anesthesia. Approximately 2 weeks later, urethroplasty was performed to create an enlarged stoma with the diverticulum, thereby preventing urine from pooling in the diverticulum and potentially reducing the risk of future urolith formation. The urethroplasty site healed well with no reported complications or evidence of urolith recurrence 6 months after surgery. CLINICAL RELEVANCE Urolithiasis is common in guinea pigs, and urethral diverticulum and intraluminal urolith formation should be considered as a potential differential diagnosis for a subcutaneous mass along the distal aspect of the urethra. Creation of a urethral stoma from a urethral diverticulum via urethroplasty achieved a successful outcome in this patient.

Influence of trial repetition on lameness during force platform gait analysis in a heterogeneous population of clinically lame dogs each trotting at its preferred velocity.

OBJECTIVE To determine variance effects influencing ground reaction forces (GRFs) in a heterogeneous population of lame dogs during trotting. ANIMALS 30 client-owned dogs with thoracic limb lameness and 31 dogs with pelvic limb lameness. PROCEDURES GRFs, velocity, height at the dorsal aspect of the scapulae (ie, withers), and shoulder height were obtained. Each dog was trotted across a force platform at its preferred velocity. Variance effects for 12 velocity and associated relative velocity (V*) ranges were examined. RESULTS Individual dog, velocity, V*, and limb significantly influenced GRFs. Withers height V* ranges were associated with small variance in GRFs, but all absolute and V* ranges were associated with significant effects for all 4 limbs and both types of lameness. Significant changes in lame limb GRFs and velocity in ipsilateral trials in dogs with thoracic limb and pelvic limb lameness were evident with trial repetition. Withers height V* range of 0.55 to 0.93 captured a large proportion of trials (> 90%) in dogs with thoracic limb or pelvic limb lameness, with limited effects on peak vertical force and vertical impulse. CONCLUSIONS AND CLINICAL RELEVANCE Trial repetition caused alterations to GRFs and subject velocity that may have confounded assessment of lameness, which supported the concept that a priori selection of a velocity or V* range for force platform gait analysis should use a range that captures valid trials efficiently while minimizing GRF variance. These ranges typically would span the preferred velocity of subject dogs, such as withers height V* of 0.55 to 0.93.

Principles of Wound Management and Wound Healing in Exotic Pets.

The care of wounds in exotic animal species can be a challenging endeavor. Special considerations must be made in regard to the animal's temperament and behavior, unique anatomy and small size, and tendency toward secondary stress-related health problems. It is important to assess the entire patient with adequate systemic evaluation and consideration of proper nutrition and husbandry, which could ultimately affect wound healing. This article summarizes the general phases of wound healing, factors that affect healing, and principles of wound management. Emphasis is placed on novel methods of treating wounds and species differences in wound management and healing.