Suture-free technique for canine ureteral resection-anastomosis using a microvascular anastomotic system: a cadaveric study.

OBJECTIVE: To describe a suture-free technique for canine ureteral resection-anastomosis using a microvascular anastomotic system (MAS) and to compare surgical time and burst pressure of hand-sewn (HS) ureteral end-to-end anastomosis with the MAS technique. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Canine cadavers (n = 8). METHODS: For each cadaver, 1 ureter was randomly assigned to undergo HS anastomosis and the contralateral ureter had MAS anastomosis. The first 3 cadavers (6 ureters) were used to refine the MAS technique. In the other 5 dogs, surgical time and ureteral burst pressure were compared between groups (n = 5 ureters/group). RESULTS: Preliminary procedures showed that selective impaling of the mucosa and submucosa (without muscularis and adventitia) is necessary to allow complete mechanical interlock of the anastomotic rings for the MAS technique. Median anastomotic time was significantly shorter for MAS (7.6 min) than HS (16.6 min; p = .029) and burst pressure higher for MAS (393 cm H2 O) than HS (180 cm H2 O; p = .012). CONCLUSION: This study demonstrated the feasibility of a suture-free technique of canine ureteral resection-anastomosis using a commercially available MAS. The MAS anastomosis was faster and had higher burst strength compared with the HS anastomosis.

A biomechanical evaluation of three drop wire configurations.

OBJECTIVE: Evaluate effect of adding drop wires to single-ring constructs. STUDY DESIGN: Biomechanical study SAMPLE POPULATION: Single ring circular external skeletal fixator constructs stabilizing a Delrin segment bone model. METHODS: Eight replicates of 5 constructs made with 66 mm complete rings, 1.6 mm olive wires, and a 15.9-mm diameter Delrin rod were loaded in axial compression, craniocaudal and mediolateral bending, and torsion. Constructs tested were: (1) base single-ring construct; (2) single-ring construct with a drop wire mounted on fixation bolts; (3) single-ring construct with a drop wire mounted on 1-hole posts; (4) single-ring construct with a drop wire mounted on 2-hole posts; and (5) 2-ring construct. Construct stiffness for each mode of loading was compared using repeated measures ANOVAs (P ≤ .05). RESULTS: Axial compression and torsion: the 2-ring construct was stiffer than all others. Drop wire constructs were stiffer than the single-ring construct, but not significantly different from each other. Craniocaudal bending: the 2-ring construct was stiffest with the 2-hole post construct being stiffer than all except the 2-ring construct. Mediolateral bending: the 2-hole post construct was stiffer than the 2-ring construct, which was stiffer than the 1-hole post construct, which was stiffer than the fixation-bolt construct, which was stiffer than the single-ring construct. CONCLUSIONS: Drop wires improved stiffness of single-ring constructs in all loading modalities. Positioning the drop wire farther from the ring surface significantly improved craniocaudal and mediolateral bending stiffness, but did not affect axial compression and torsional stiffness.