Objective—To compare application time, accuracy of tibial plateau slope (TPS) correction, presence and magnitude of rotational and angular deformities, and mechanical properties of 5 canine tibial plateau leveling methods.
Sample Population—27 canine tibial replicas created by rapid prototyping methods.
Procedure—The application time, accuracy of TPS correction, presence and magnitude of rotational and angular deformation, and construct axial stiffness of 3 internal fixation methods (tibial plateau leveling osteotomy, tibial wedge osteotomy, and chevron wedge osteotomy [CWO]) and 2 external skeletal fixation (ESF) methods (hinged hybrid circular external fixation and wedge osteotomy linear fixation [WOLF]) were assessed.
Results—Mean bone model axial stiffness did not differ among methods. Mean application time was more rapid for WOLF than for other methods. Mean TPSs did not differ from our 5° target and were lower for ESF methods, compared with internal fixation methods. Mean postoperative rotational malalignment did not differ from our target or among groups. Mean postoperative medio-lateral angulation did not differ from our target, except for CWO. Internal fixation methods lead to axially stiffer constructs than ESF methods. Reuse of ESF frames did not lead to a decrease in axial stiffness.
Conclusions and Clinical Relevance—The 5 tibial plateau leveling methods had acceptable geometric and mechanical properties. External skeletal fixation methods were more accurate as a result of precise data available for determining the exact magnitude of correction required to achieve a 5° TPS.
Objective—To biomechanically and histologically compare single-layer continuous Cushing and simple continuous appositional cystotomy closure in rats with xylene-induced cystitis.
Animals—40 female Sprague-Dawley rats.
Procedure—Rats were anesthetized, their urinary bladders catheterized and evacuated, and xylene instilled in each bladder for 5 minutes and then aspirated. Forty-eight hours later, ventral midline celiotomy and cystotomy (8 mm) were performed. Cystotomies were closed with 6-0 poliglecaprone 25 by use of a single-layer continuous Cushing or simple continuous appositional pattern (20 rats/group), and cystotomy times were recorded. Rats were allocated to healing durations (5 rats/group) of 0, 3, 7, and 14 days. Celiotomies were closed in a routine manner. After the allotted healing interval, another celiotomy was performed, the urethra cannulated, and ureters ligated. The cannula was secured to the urethra, and the bladder infused at 0.1 mL/min. Leak pressure volume, leak pressure, peak pressure volume, and peak pressure were recorded via a pressure transducer. Bladders were harvested and histologically assessed.
Results—Cystotomy time, biomechanical testing values, and overall inflammation scores did not differ between closure methods for any healing duration. Both methods had significantly greater leak pressures, with the appositional method also having significantly greater peak pressures on day 7, compared to day 0. Biomechanical testing values decreased from day 7 to 14 as a result of juxtaincisional weakening of the bladder and xylene-induced changes in collagen.
Conclusions and Clinical Relevance—Simple continuous appositional was equal biomechanically and histologically to continuous Cushing for all comparison variables. Poliglecaprone 25 was acceptable for cystotomy closure.