Effect of Perineal Urethrostomy on the Length of the Urethra of the Cat: A Cadaveric Study.

Perineal urethrostomy in cats is indicated for urethral pathologies located distal to the bulbourethral glands. The description of the bulbourethral glands as the cranial landmark when performing a PU is based on the increased urethral diameter at this location, rather than on an anatomical limitation. This suggests that urethral pathologies cranial to the bulbourethral glands could potentially be treated with PU. At present, the extent to which the pelvic urethra can be mobilized is unknown. Characterization and quantification of the effect of PU on the pelvic urethra is required prior to attempting to define the location of the pelvic urethra, cranial to the bulbourethral glands, which can be exteriorized when performing a PU. Our aim was to characterize and quantify the effect of performing a PU on the location and length of the pelvic urethra. METHODS: Ten male feline cadavers were used, and four markers were placed on the pelvic urethra via a ventral approach to the peritoneal and pelvic cavities. Two orthogonal radiographic views were acquired prior and subsequent to performing a PU. The distance of each marker to a predefined landmark/origin and the distances of the markers relative to each other were measured on all radiographs. RESULTS: PU resulted in significant caudal translation of the markers relative to the predefined landmark on all radiographic views; however, PU did not result in a significant change in the distances between the markers. CONCLUSIONS: Performing a PU results in caudal translation and minimal stretching of the mobilized pelvic urethra.

Acute mesenteric ischemia-like syndrome associated with suspected Spirocerca lupi aberrant migration in dogs.

OBJECTIVE: To describe acute mesenteric infarction due to suspected Spirocerca lupi aberrant migration in 5 dogs. CASE SERIES SUMMARY: All dogs were large breed, none of which exhibited typical clinical signs associated with spirocercosis. All dogs were eventually diagnosed with septic peritonitis. On exploratory laparotomy, thickening of the jejunal arteries, surrounding mesojejunum, and segmental necrosis were identified. Similar thickening and hematoma formation were found in other regions of the mesentery. In 4 of the cases, the necrotic segment was located in the distal jejunum. Histology revealed thrombotic mesenteric vessels with intralesional S. lupi nematode larvae. Resection and anastomosis of the necrosed section was performed and all but 1 dog survived and were discharged within 1-6 days. NEW OR UNIQUE INFORMATION PROVIDED: Spirocerca lupi is a potential cause of mesenteric infarction in endemic areas when no other obvious etiology is identified.

Normograde and retrograde pinning of the distal fragment in feline humeral fractures.

OBJECTIVE: To determine if normograde and retrograde pinning of the distal humeral fragment, performed to maximize pin purchase in this fragment, would damage vital structures in and around the elbow and shoulder joints in cats. STUDY DESIGN: Anatomic study. SAMPLE POPULATION: Cadaveric cats (n = 12; 24 thoracic limbs). METHODS: Twelve thoracic limb pairs were harvested from domestic short-haired cats and 1 limb from each pair was allocated to 1 of 3 groups. A transverse osteotomy was created at the junction of the middle and distal thirds in the diaphyseal osteotomy group (n = 8) and proximal to the supracondylar foramen in the metaphyseal osteotomy group (n = 8). Humeri in the normograde group (n = 8) were left intact. Retrograde pinning of the distal fragment in both osteotomy groups was performed with the elbow flexed. Pins were driven into the medial epicondyle until they exited the skin caudal to the elbow and dissection of the soft tissues around the exit tract of the pin was performed. The fracture was reduced and the pin was advanced until it exited the proximal humeral fragment. In the specimens in normograde group, pinning was initiated on the distal aspect of the medial epicondyle. A 1.0 mm guide hole was drilled from the medial epicondyle to the center of the medullary cavity of the distal humeral metaphysis. A bevelled 1.5 mm IM pin was driven proximally through the guide hole until it exited the proximal humerus. RESULTS: Pins exiting the distal aspect of the medial epicondyle passed through muscle origins in 5 specimens in the diaphyseal osteotomy group and in all 8 specimens in the metaphyseal group. The ulnar nerve was entrapped in 1 specimen in both the metaphyseal osteotomy and diaphyseal osteotomy groups. The articular cartilage of the trochlea was damaged in 5 specimens in the diaphyseal osteotomy group and in 1 specimen in the metaphyseal osteotomy group. There was no damage to articular or periarticular structures by pins exiting the proximal humerus. CONCLUSION: Retrograde pinning of the distal fragment in humeral fractures in the cat may damage the articular cartilage and cannot be recommended. Normograde pinning is safe and maximizes pin purchase in the distal fragment.