ObjectiveTo compare the accuracy of pedicle screw insertion (PSI) into canine lumbosacral vertebrae with custom‐made three‐dimensionally (3D)‐printed drill guides or freehand insertion.Study designEx vivo study.Sample populationNineteen canine lumbosacral specimens.MethodsDrill guides for PSI were designed on the basis of safe screw insertion trajectories by using preoperative computed tomography (CT) and produced by 3D printing of templates. Right and left sides of the specimens were randomly allocated to two groups; 4‐mm pedicle screws were inserted in L5‐L6 and L7‐S1 spinal segments either freehand (control group) or with custom‐made drill guides (guide group). Sixty‐six screws were inserted with each method. Insertion angles (α, β), bone stock, and vertebral canal breach were assessed according to postoperative CT. χ2 Tests were used to compare vertebral canal breach between groups and vertebrae.ResultsBreaches in the vertebral canal were less common (P < .001) when screws were placed with a guide in the guide group (9/66, 14%) than without a guide (30/66, 45%). The rate of vertebral canal breach differed at L5 (P = .021) but not at L6 (P = .05), L7 (P = .075) or S1 (P = .658). The angle of insertion (α) did not differ between specimens with and without breaches (guide, P = .068; control, P = .394).ConclusionThe use of a customized 3D‐printed guide generally improved the accuracy of PSI in canine lumbosacral vertebrae, although statistical significance was reached only at L5.Clinical significanceThe use of customized drill guides may be considered as an alternative to freehand PSI in the lumbosacral area, especially for L5‐L6 vertebrae.

Screw loosening occurred less often but the change in pelvic canal alignment was not significantly different in ilial fractures repaired with LPS or dLPS compared to ilial fractures repaired with DCP. Locking plating of ilial fractures in cats may offer advantages compared to nonlocking plating.

Objective: To determine the biomechanical properties of plating techniques for comminuted feline ilial fractures. Study design: Ex vivo study on 40 paired feline hemipelves. Sample population: Forty paired fresh-frozen hemipelves that had been collected from 20 cats aged 2-6 years and weighing 4.0-5.5 kg. Methods: A transverse 3-mm gap was created in each ilium. Hemipelves were fixed with one of the following methods (n = 10 per group): (1) a dorsal plate and nonlocking screws, (2) a lateral plate and nonlocking screws, (3) a lateral plate and locking screws, or (4) a lateral and dorsal locking compression plate using nonlocking screws. Each specimen was subjected to incremental, sinusoidal cyclic loading until failure, defined as 10-mm displacement. The initial stiffness and number of cycles required to reach 1-, 2-, 5-, and 10-mm axial displacement were statistically analyzed. Results: The initial stiffness and number of cycles to failure were higher in specimens fixed with double nonlocking plates than in all other fixations (P < .05) except specimens fixed with lateral locking plate at 10-mm displacement (P = .44). Locking implants withstood more cycles to 5-(P < .05) and 10-mm (P < .05) displacement compared with other single-plate nonlocking groups. Screw loosening occurred only in the 3 nonlocking fixations. Conclusion: Double plating improved stiffness and resistance to failure of comminuted feline ilial fracture constructs compared with all other fixations. Single locking plates produced superior constructs compared with single nonlocking constructs. Clinical significance: Locking implants are recommended to repair comminuted feline ilial fractures for their extended fatigue life and resistance to screw loosening. Orthogonal plating offers a strong nonlocking alternative.

No abstract

OBJECTIVE To provide an objective, quantitative morphometric description of the caudal cervical intervertebral disk (IVD) spaces of dogs. SAMPLE Vertebral specimens consisting of C4 through C7 from 5 medium-sized dogs. PROCEDURES CT images were obtained with the specimens positioned in neutral, flexion, extension, and lateral bending positions. Size and shape of the cranial and caudal end plates, angle between the end plates (IVD wedge angle), and craniocaudal distance (IVD width) between end plates for the 4 loading positions were measured and compared for the 3 segments (C4-5, C5-6, and C6-7). RESULTS End plate size and shape, IVD wedge angle, and IVD width were not significantly different among the 3 segments. Caudal cervical end plates were consistently larger than cranial cervical end plates. The IVD wedge angle ranged from −4.8° to 15.2°. Flexion induced a reduction in IVD width in the ventral portion of the IVD, whereas extension induced a decrease in width in the dorsal portion of the IVD. Central IVD width remained unchanged among the loading positions. CONCLUSIONS AND CLINICAL RELEVANCE Unique morphometric and dynamic characteristics of the caudal cervical IVD space of dogs were detected. These findings may help investigators when designing IVD prostheses for dogs with cervical spondylomyelopathy.

Analysis of in vitro results suggested that laminar stabilization of vertebral segments provided greater stiffness than did vertebral body plating.

ObjectiveTo compare mechanical properties of intact feline medial collateral ligaments and three techniques for treatment of feline medial tarsal instability.Study designControlled laboratory study.Sample populationForty‐eight normal, adult feline tarsi.MethodsThree repairs were tested: a bone tunnel with polypropylene (PP) suture, a bone tunnel with polyethylene (PE) cord, and a knotless anchor technique with PE cord. A cyclic (6‐N preload; 5‐N amplitude; 2‐Hz frequency) tensile test (600 cycles) was performed on feline tarsi with either the long or the short medial tarsal ligament intact, with each reconstruction technique followed by a single‐cycle load‐to‐failure test (0.5 mm/s) with a failure point at 2 mm of displacement. Total elongation, peak‐to‐peak elongation, stiffness, and maximum load to failure point were compared with the intact condition.ResultsNo differences in stiffness, total elongation, or peak‐to‐peak elongation were found between specimens repaired with the knotless technique and intact controls (P > .04), whereas tarsi repaired with the tunnel technique and PP were weaker (P < .008). Total and conditioning elongation were greater after tunnel reconstruction with PP than after knotless reconstruction (P = .005). Mean load to 2 mm of displacement tended (P = .03) to be higher after knotless than after knotted PP repairs and did not differ (P = .47) between tarsi repaired with the tunnel or anchor repairs with PE.ConclusionThe mechanical properties of intact tarsi were superior to those of tarsi repaired with tunnel techniques and PP but were similar to those of tarsi repaired with knotless techniques with PE.Clinical significanceFeline tarsal stabilization with the knotless technique for tarsal medial collateral ligament insufficiency may reduce the requirement for or duration of postoperative coaptation.

This report describes two cats with mesenteric volvulus that were successfully treated. To the authors' knowledge, no reports of antemortem diagnosis or treatment of small intestinal volvulus in cats have previously been published. On the basis of the cases presented, it appears that the diagnosis of intestinal volvulus may be more difficult in cats than in dogs, but that the prognosis may not be as poor. Therefore, it is suggested that owners be encouraged to pursue surgery.