A Comparison of Simple Continuous Versus Simple Interrupted Suture Patterns for Tracheal Anastomosis After Large-Segment Tracheal Resection in Dogs

Two suture techniques for tracheal anastomosis after large-segment tracheal resection were compared. Eight cartilages were resected from the trachea of each of 12 dogs; anastomoses with 4-0 polydioxanone suture were created using a simple continuous suture technique in six dogs and a simple interrupted suture technique in six dogs. Surgical time was shorter but apposition of tracheal segments at the time of surgery was less precise with the simple continuous suture technique. The dogs were evaluated for 150 days after surgery. Clinical abnormalities after tracheal resection and anastomosis were not observed. Percent dorsoventral luminal stenosis was calculated by measuring the tracheal lumen diameter on lateral cervical radiographs. Percent luminal stenosis was calculated planimetrically using a computerized digitizing tablet. Anastomotic stenosis was mild in all dogs; however, the mean percent luminal stenosis determined planimetrically was significantly greater for dogs that had the simple continuous suture technique. Planimetric measurements of cross-sectional area made before and after formalin fixation were not significantly different. Radiographic determination of percent dorsoventral luminal stenosis was a poor predictor of diminution of cross-sectional area determined planimetrically.     

Comparison of Computed Tomographic and Radiographic Popliteal Lymphangiography in Normal Dogs

Objective: To (1) describe computed tomographic (CT) popliteal lymphangiography; (2) compare the number of thoracic duct (TD) branches detected by CT and by radiography after popliteal lymphangiography; and (3) to compare the number of branches detected after left and right popliteal lymphangiography. Study Design: Experimental study. Animals: Adult dogs (n=6). Methods: A randomly selected popliteal lymph node was percutaneously injected with 12 mL iodinated contrast medium through a 25‐g butterfly catheter over 4–5 minutes. Lateral and ventrodorsal (VD) thoracic radiograph projections and thoracic CT were performed. The procedure was repeated using the contralateral lymph node after a 48–72 hours washout period. Results: One dog had TD branches visible on CT but not on radiographs. A significantly greater number of TD branches were observed with CT popliteal lymphangiography compared with lateral and VD radiographic popliteal lymphangiography (P=.003 and P<.001, respectively). The number of visible TD branches observed between the 6th thoracic and 1st lumbar vertebrae were not significantly different in these dogs (P=.146). A significant difference in number of TD branches observed was not found after left or right popliteal lymph node injection (P=.097). Conclusions: CT popliteal lymphangiography consistently identified a greater number of TD branches when compared with radiographic popliteal lymphangiography. Injection of either popliteal lymph node resulted in the same number of TD branches being observed.     

Age, Tibial Plateau Angle, Sex, and Weight as Risk Factors for Contralateral Rupture of the Cranial Cruciate Ligament in Labradors

Objective— To compare rates of contralateral cranial cruciate ligament rupture (CCLR) in Labradors based on age and weight at initial rupture, sex, and tibial plateau angle (TPA) and to determine whether Labradors that rupture their initial cranial cruciate ligament (CCL) at an earlier age (<4 years) are more likely to rupture their contralateral side within a certain period of time. Study Design— Case series. Animals— Labradors (n=94) that had tibial plateau leveling osteotomy (TPLO). Methods— Two groups: no contralateral rupture (NR) and contralateral rupture (CR) were compared for significant (P<.05) differences in percentage of subsequent cruciate tears using a Wilcoxon's rank‐sum tests for continuous variables and Fisher's exact test for sex. Adjusted odds ratios for likelihood of subsequent cruciate tears (yes/no) were estimated using logistic regression. Associations of these characteristics with time to subsequent rupture were assessed using Kaplan–Meier survival analysis estimation. Predictors of presentation with bilateral ruptures (BR) versus single rupture were also evaluated using Wilcoxon's rank‐sum tests and a generalized Fisher's exact test. Results— Subsequent CCLR occurred in 45 dogs (48%), and BR on admission were identified in 10 dogs (10.6%). Comparing NR and CR dogs, there were no significant differences between age or weight at initial rupture, sex or TPA; however there were associations toward longer time to CR for dogs older than the median age and female dogs (intact and spayed). There were no significant differences in age, sex, weight, or TPA of dogs with bilateral CCL ruptures compared with initial unilateral ruptures; however, there was a trend toward dogs presenting at an older age and with lower TPA's in the BR group. Among the 84 NR/CR dogs, the median time to rupture of the contralateral CCL was 5.5 months (95% CI 5.2–5.7). Conclusions— Age and weight at initial rupture, sex, and TPA does not affect likelihood or rate of contralateral CCL rupture or presentation with bilateral CCL ruptures. Clinical Relevance— Approximately 50% of Labradors will rupture the contralateral CCL within 5.5 months of the initial rupture but age, weight, sex, and TPA cannot be used as predictive features.     

Laparoscopic Cryptorchid Castration in Standing Horses

Objective — This article describes a new technique for laparoscopic cryptorchid castration in standing horses. Study Design — Prospective study. Animals or Sample Population — Eight horses aged 11 months to 3 years and weighing between 300 and 643 kg. Methods — Food was withheld for 24 to 36 hours, and then horses were sedated with detomidine HC1 (0.02 to 0.03 mg/kg) and butorphanol tartrate (0.02 mg/kg). The paralumbar fossa region was desensitized with 2% mepivacaine in an inverted “L” pattern and caudal epidural anesthesia was administered with either xylazine (0.18 mg/kg diluted to 10 to 15 mL with 0.9% sodium chloride) or a combination of 2% mepivacaine and xylazine (0.18 mg/kg). Initial laparoscopic exploration was performed from the left flank; in three horses, right flank laparoscopy was needed to complete the procedure. The spermatic cord was ligated within the abdomen with one or two sutures of 0 polydioxanone suture, and the testis or testes removed through a flank incision. Results — In five horses with no palpably descended testes, standing laparoscopy was the only procedure performed, whereas in two horses, the abdominal testis was removed laparoscopically, and the descended testis was removed under short acting anesthesia. In one horse, with nonpalpable testes, it was determined by laparoscopic observation that the testes were in the inguinal canal, and castration was performed under general anesthesia. No surgical or postoperative complications were noted. The right side of the abdomen, and especially the right vaginal ring, could be easily observed from the left side by passing the laparoscope through a small perforation in the mesocolon of the descending colon or by elevating the descending colon with an instrument or by use of an arm in the rectum. Conclusions — The standing laparoscopic approach combined with or without short-acting anesthesia to remove the descended testis is easily performed. Clinical Relevance — This approach will provide surgeons with another option to castrate cryptorchid stallions.     

Hepatic Lobe Torsion as a Cause of Colic in a Horse

A 14-year-old Arabian gelding was examined for colic. An exploratory celiotomy was subsequently performed and the left lobe of the liver was found to be twisted. The lobe was resected using a TA-90 surgical stapling instrument. Histologic examination of the resected liver indicated portal vein and sinusoid dilation and congestion with blood. There were focal areas of necrosis and bacterial cocci and rods throughout the section. The histologic findings were consistent with hepatic lobe torsion. After surgery, the horse was treated with broad spectrum antibiotics, anti-inflammatory drugs, heparin, and intravenous fluids. The horse recovered without complications, although serum liver enzymes remained elevated for more than 1 week after surgery. Seven months after surgery the horse showed no adverse affects from the disease.     

Controlled Cross Circulation in Dogs: Effects on Donor Hemodynamics

Controlled cross circulation (CCC) was performed in six pairs of dogs for 45 minutes with aortic cross clamping and cardioplegia. Data were collected in donor dogs at 10 minute intervals three times before, three times during, and three times after CCC and included arterial blood pressure, pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), cardiac index (CI), heart rate (HR), blood gas analysis, temperature, maximum rate of rise of left ventricular pressure dP/dt max/End diastolic volume (EDV), blood volume (BV), complete blood count (CBC) and activated clotting times (ACT). Pulse pressure (PP), systemic vascular resistance (SVR), oxygen delivery (Do₂), and left ventricular cardiac work (LVCW) were calculated. Arterial blood pressure, CVP, blood gas analysis, temperature, BV, CBC, and ACT were measured in recipient dogs. During CCC, donor hemodynamic changes resembled those observed in models of acute onset arteriovenous fistulas. Insidious BV shifts can occur despite the use of occlusive roller pumps. After CCC, donor hemodynamics resembled acute blood loss, characterized by decreases in mean arterial pressure (MAP), CVP, PCWP, and CI, and increases in SVR and dP/dt max/EDV. These changes were probably caused by pump imbalance and BV shift to the recipient dog.