Patricia A. Sura

Use of Nitinol Stents for End‐Stage Tracheal Collapse in Dogs

OBJECTIVE To report bronchoscopic placement of nitinol stents (Vet Stent-Trachea®) for improvement of end-stage clinical signs in dogs with tracheal collapse. STUDY DESIGN Case series. SAMPLE POPULATION Dogs (n = 18). METHODS Medical records (January 1, 2004-October 31, 2008) were searched for dogs with a diagnosis of tracheal collapse; 18 dogs met inclusion criteria. Tracheal diameter was compared before and after stent deployment. Stent dimensions were compared after stent deployment and at radiographic follow-up. RESULTS There was a significant difference in the minimum tracheal diameter when initial and post deployment tracheal diameters were compared (P = .003). Stent length was significantly shorter at follow-up when compared to post deployment measurements (P = .004). Owner assessment of outcome was available for all dogs with 11.1% mortality within 60 days. Complications were documented in 9 dogs. CONCLUSIONS Use of a nitinol stent (Vet Stent-Trachea®) in dogs with end-stage tracheal collapse is associated with a fair to good outcome despite significant temporal stent fore shortening after bronchoscopic placement.

LAPAROSCOPIC-ASSISTED OVARIECTOMY OF TIGERS (PANTHERA TIGRIS) WITH THE USE OF THE LIGASURE™ DEVICE

Laparoscopic ovariectomy was performed in seven tigers with the use of a vessel-sealing device and a three-port technique. A comparison group of seven tigers that underwent traditional ovariohysterectomy was assembled with the use of a medical records search. Mean operative times for laparoscopic ovariectomy were compared to standard ovariohysterectomy, and mean combined laparoscopic incision length compared to standard ovariohysterectomy incision lengths. Significance was set at P < or = 0.05. Mean surgical time for laparoscopic ovariectomy (82 min, range 71-126 min) was significantly shorter than standard ovariohysterectomy surgical time (129 min, range 80-165 min, P = 0.007). Mean combined laparoscopic incision length (8.07 cm, range 3.80-9.50 cm) was significantly shorter than the mean incision length for standard ovariohysterectomy (13.57 cm, range 12.00-20.00 cm, P = 0.009). There were no clinically important complications observed in either group. Laparoscopic ovariectomy has a significantly shorter surgical time and combined incision length compared to standard ovariohysterectomy in tigers, and appears to be a safe and rapid sterilization method for tigers. Equipment cost and the necessity for advanced training may limit its use in some institutions. Further prospective evaluation is warranted to determine whether it is associated with decreased morbidity, mortality, or cost.

Comparison of first-intention healing of carbon dioxide laser, 4.0-MHz radiosurgery, and scalpel incisions in ball pythons (Python regius)

OBJECTIVE To evaluate first-intention healing of CO(2) laser, 4.0-MHz radiowave radiosurgery (RWRS), and scalpel incisions in ball pythons (Python regius). ANIMALS 6 healthy adult ball pythons. PROCEDURES A skin biopsy sample was collected, and 2-cm skin incisions (4/modality) were made in each snake under anesthesia and closed with surgical staples on day 0. Incision sites were grossly evaluated and scored daily. One skin biopsy sample per incision type per snake was obtained on days 2, 7, 14, and 30. Necrotic and fibroplastic tissue was measured in histologic sections; samples were assessed and scored for total inflammation, histologic response (based on the measurement of necrotic and fibroplastic tissues and total inflammation score), and other variables. Frequency distributions of gross and histologic variables associated with wound healing were calculated. RESULTS Gross wound scores were significantly greater (indicating greater separation of wound edges) for laser incisions than for RWRS and scalpel incisions at all evaluated time points. Necrosis was significantly greater in laser and RWRS incisions than in scalpel incision sites on days 2 and 14 and days 2 and 7, respectively; fibroplasia was significantly greater in laser than in scalpel incision sites on day 30. Histologic response scores were significantly lower for scalpel than for other incision modalities on days 2, 14, and 30. CONCLUSIONS AND CLINICAL RELEVANCE In snakes, skin incisions made with a scalpel generally had less necrotic tissue than did CO(2) laser and RWRS incisions. Comparison of the 3 modalities on the basis of histologic response scores indicated that use of a scalpel was preferable, followed by RWRS and then laser.

Magnetic resonance imaging of canine mast cell tumors.

Mast cell tumors (MCT) are the most common cutaneous tumors in dogs. Our purpose was to describe the magnetic resonance (MR) imaging characteristics of cutaneous MCT and to identify imaging characteristics that allow differentiation of metastatic from normal lymph nodes. Eight dogs with a total of nineMCT were imaged as were their presumed draining and associated contralateral lymph nodes. The signal intensity of tumors and lymph nodes was compared to adjacent musculature. On T2-W images, 7/9 MCT were hyperintense to muscle and 2/9 were isointense. On T1-W images, 8/9 MCT were isointense and 1/9 were mildly hypointense. All tumors were strongly contrast enhancing; 5/9 were homogeneous and 4/9 heterogeneous in their enhancement patterns. Six lymph node pairs were included in the evaluation (five sentinel lymph nodes with metastases, one without, and six contralateral lymph nodes). Metastatic lymph nodes were significantly larger than their contralateral lymph nodes (P = 0.039). All lymph nodes were isointense on T1-W images and hyperintense on T2-W images. 5/5 metastatic and 2/7 normal lymph nodes were heterogeneously T2-hyperintense. All lymph nodes were moderately to strongly contrast enhancing. 4/5 metastatic and 2/7 normal lymph nodes had heterogeneous enhancement patterns. While heterogeneity was more common in metastatic than in normal lymph nodes, this difference was not significant (P = 0.058 for T2-W images; P = 0.234 for postcontrast images). MR imaging may be useful in the presurgical evaluation and clinical staging of cutaneous MCT.

SELECTED CLINICAL, BIOCHEMICAL, AND ELECTROLYTE ALTERATIONS IN ANESTHETIZED CAPTIVE TIGERS (PANTHERA TIGRIS) AND LIONS (PANTHERA LEO)

Abstract: A prospective study to assess changes in selected plasma biochemistry and electrolyte values, plasma insulin and aldosterone concentrations, and electrocardiography (ECG) was performed on eight female captive tigers (Panthera tigris) and three lions (Panthera leo) undergoing general anesthesia for elective laparoscopic ovariectomy. Each animal was sedated with medetomidine (18–25 μg/kg) and midazolam (0.06–0.1 mg/kg) intramuscularly, and anesthesia was induced with ketamine (1.9–3.5 mg/kg) intramuscularly and maintained with isoflurane. Venous blood samples were collected and analyzed for plasma biochemistry parameters and insulin and aldosterone concentrations. An ECG was recorded at the time of each blood sample collection. Mean plasma potassium, glucose, phosphorus, and aldosterone concentrations increased during anesthesia (P ≤ 0.05). One tiger developed hyperkalemia (6.5 mmol/L) 2.5 hr after anesthetic induction. Plasma insulin concentrations were initially below the low end of the domestic cat reference interval (72–583 pmol/L), but mean insulin concentration increased (P ≤ 0.05) over time compared with the baseline values. Three tigers and two lions had ECG changes that were representative of myocardial hypoxemia. Based on these results, continuous monitoring of clinical and biochemical alterations during general anesthesia in large nondomestic felids is warranted, and consideration should be given to reversal of medetomidine in these animals should significant changes in electrolytes or ECG occur.