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1.
Vet Surg ; 49(1): 187-199, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31777975

RESUMO

OBJECTIVE: To determine the ability of tibial plateau leveling osteotomy (TPLO) to address abnormal femorotibial kinematics caused by cranial cruciate ligament (CCL) rupture during walking in dogs. STUDY DESIGN: Prospective, clinical. ANIMALS: Sixteen dogs (20-40 kg) with unilateral complete CCL rupture. METHODS: Lateral view fluoroscopy was performed during treadmill walking preoperatively and 6 months after TPLO. Digital three-dimensional (3D) models of the femora and tibiae were created from computed tomographic (CT) images. Gait cycles were analyzed by using a 3D-to-2D image registration process. Craniocaudal translation, internal/external rotation, and flexion/extension of the femorotibial joint were compared between preoperative and 6-month postoperative time points for the affected stifle and 6-month postoperative unaffected contralateral (control) stifles. RESULTS: In the overall population, CCL rupture resulted in 10 ± 2.2 mm (mean ± SD) cranial tibial translation at midstance phase, which was converted to 2.1 ± 4.3 mm caudal tibial translation after TPLO. However, five of 16 TPLO-treated stifles had 4.1 ± 0.3 mm of cranial tibial subluxation during mid-to-late stance phase, whereas 10 of 16 TPLO-treated stifles had 4.3 ± 0.4 mm of caudal tibial subluxation throughout the gait cycle. Overall, postoperative axial rotational and flexion/extension patterns were not different from control, but stifles with caudal tibial subluxation had more external tibial rotation during mid-to-late stance phase compared with stifles with cranial tibial subluxation. CONCLUSION: TPLO mitigated abnormal femorotibial kinematics but did not restore kinematics to control values in 15 of 16 dogs during walking. CLINICAL SIGNIFICANCE: Tibial plateau leveling osteotomy reduces cranial tibial subluxation during walking, but persistent instability is common.

2.
Vet Clin North Am Small Anim Pract ; 50(1): 135-153, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31635915

RESUMO

Minimally invasive plate osteosynthesis (MIPO) is a biologically friendly approach to fracture reduction and stabilization that is applicable to many radius and ulna fractures in small animals. An appropriate knowledge of the anatomy of the antebrachium and careful preoperative planning are essential. This article describes the MIPO technique, which entails stabilization of the fractured radius with a bone plate and screws that are applied without performing an extensive open surgical approach. This technique results in good outcomes, including a rapid time to union and return of function.


Assuntos
Gatos/cirurgia , Cães/cirurgia , Membro Anterior/cirurgia , Fixação Interna de Fraturas/veterinária , Fraturas Ósseas/veterinária , Procedimentos Cirúrgicos Minimamente Invasivos/veterinária , Animais , Gatos/lesões , Cães/lesões , Membro Anterior/lesões , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/cirurgia
3.
Vet Clin North Am Small Anim Pract ; 50(1): 241-261, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31653536

RESUMO

Arthrodesis is an elective surgical procedure that aims at eliminating pain and dysfunction by promoting deliberate osseous fusion of the involved joint(s). Percutaneous plating can be used to perform carpal and tarsal arthrodeses in dogs and cats. After cartilage debridement is performed, the plate is introduced through separate plate insertion incisions made remote to the arthrodesis site and advanced along an epiperiosteal tunnel, and screws are inserted through the 3 existing skin incisions. The primary advantage of this technique is a decreased risk of soft-tissue complications, including postoperative swelling, ischemia, and wound dehiscence. Preliminary clinical results have been promising.


Assuntos
Artrodese/veterinária , Placas Ósseas/veterinária , Fixação Interna de Fraturas/veterinária , Animais , Artrodese/métodos , Fixação Interna de Fraturas/métodos
4.
Case Rep Vet Med ; 2019: 1439237, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31827971

RESUMO

An 18-week-old Rhodesian Ridgeback puppy that was hit by a car sustained a Salter-Harris type III fracture of the left proximal tibial physis and ipsilateral diaphyseal femoral and tibial fractures. The diaphyseal fractures were successfully stabilized with bone plate fixation. Premature closure of the caudal aspect of the proximal tibial physis, secondary to the proximal physeal fracture, resulted in an excessively high tibial plateau angle (TPA) of 50° with a limb length discrepancy of 13% by 24 weeks of age. The deformity was addressed by performing a proximal tibial osteotomy and subsequent distraction osteogenesis to reduce the TPA while concurrently lengthening the crus. A radial osteotomy was performed in the proximal metaphyseal region and the hinged fixator was applied. Distraction was initiated the day following surgery at a rate of 1 mm per day as measured along the caudal cortex of the tibia with a rhythm of three distractions daily. Distraction was terminated 19 days postoperatively. Sequential distraction of the osteotomy resulted in 17 mm of tibial lengthening and a final TPA of 3°. The fixator was removed 52 days after application. Complications included wire tract inflammation involving the wires securing the proximal segment and a calcaneal fracture which required bone plate stabilization. The left pelvic limb was only 8% shorter than the right pelvic limb and the dog had only a subtle lameness 12 months after surgery. The hinged circular fixator construct allowed for both the reduction of the TPA and limb segment lengthening in this dog.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31858511

RESUMO

OBJECTIVES: The aim of this study was to compare the biomechanical characteristics of locking compression plate (LCP) and conical coupling plate (CCP) constructs for the stabilization of experimentally induced gap fractures in cat tibiae. MATERIALS AND METHODS: Pelvic limbs were harvested from eight cat cadavers. Paired tibiae were stripped of all soft tissues, and randomly assigned to the LCP or CCP stabilization group. An eight-hole 2.7 mm LCP or a six-hole 2.5 mm CCP was applied to the medial surface of each tibia. A 1-cm segment of the tibia was excised centrally beneath the plate. The specimens were potted, then tested in non-destructive four-point craniocaudal and mediolateral bending, followed by non-destructive axial compression. Each construct was subsequently loaded to failure in axial compression. Bending and axial stiffness, yield load and failure load were calculated for each specimen. RESULTS: The LCP constructs were significantly stiffer than the CCP constructs when subjected to non-destructive bending and axial loading. Craniocaudal bending stiffness was significantly greater than mediolateral bending stiffness for both constructs. Yield load and failure load were significantly greater for LCP constructs compared with CCP constructs. CLINICAL SIGNIFICANCE: LCP may be a more suitable implant for stabilizing complex diaphyseal tibial fractures in cats. Additional supplemental fixation should be considered when using CCP to stabilize unreconstructed diaphyseal tibial fractures in cats. Further clinical investigation of both implants is recommended.

6.
J Am Vet Med Assoc ; 255(9): 1027-1034, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31617809

RESUMO

OBJECTIVE: To evaluate the feasibility of ultrasound-guided, temporary, percutaneous T-fastener gastropexy (TG) and gastrostomy catheter (GC) placement for providing sustained gastric decompression in dogs with acute gastric dilatation-volvulus (GDV) and to compare findings with those of trocarization. ANIMALS: 16 dogs with GDV. PROCEDURES: Dogs were randomly assigned to undergo gastric decompression by means of percutaneous trocarization (trocar group; n = 8) or temporary TG and GC placement (TTG+GC group; 8) with ultrasound guidance. The gastric volvulus was then surgically corrected, and the decompression sites were examined. Outcomes were compared between groups. RESULTS: The proportion of dogs with successful decompression did not differ significantly between the TTG+GC (6/8) and trocar (7/8) groups; median procedure duration was 3.3 and 3.7 minutes, respectively. After the failed attempts in the TTG+GC group, the procedure was modified to include ultrasound guidance during T-fastener placement. The decrease in intragastric pressure by 5 minutes after trocar or GC insertion was similar between groups. For dogs in the TTG+GC group, no significant difference in intragastric pressure was identified between 5 and 60 minutes after GC insertion. Complications included inadvertent splenic or jejunal placement in 2 dogs (TTG+GC group) and malpositioned and ineffective trocar placement in 1 dog (trocar group). All dogs survived for at least 2 weeks. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided, temporary, percutaneous TG and GC placement was safe and effective at providing sustained gastric decompression in dogs with GDV, suggesting that this technique would be ideal for dogs in which surgical delays are anticipated or unavoidable.

7.
Front Vet Sci ; 6: 292, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31555675

RESUMO

Large animal (non-rodent mammal) models are commonly used in ACL research, but no species is currently considered the gold standard. Important considerations when selecting a large animal model include anatomical differences, the natural course of ACL pathology in that species, and biomechanical differences between humans and the chosen model. This article summarizes recent reports related to anatomy, pathology, and biomechanics of the ACL for large animal species (dog, goat, sheep, pig, and rabbit) commonly used in ACL research. Each species has unique features and benefits as well as potential drawbacks, which are highlighted in this review. This information may be useful in the selection process when designing future studies.

8.
Am J Vet Res ; 80(6): 533-538, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31140845

RESUMO

OBJECTIVE: To compare mechanical properties (stiffness, yield load, failure load, and deformation at failure) of 2 pearl-type locking plate system (PLS) constructs (PLS 1 and PLS 2) in a simulated fracture gap model and to compare screw push-out forces of the 2 PLSs with and without plate contouring. SAMPLE: 40 PLS constructs. PROCEDURES: Mechanical properties of uncontoured PLS 1 (n = 8) and PLS 2 (8) constructs were evaluated in synthetic bone-plate models under axial compression. Screw push-out forces were evaluated in 6 uncontoured and 6 contoured PLSs of each type. Variables of interest were compared between PLS groups and between contoured and uncontoured plates by statistical methods. RESULTS: Yield and failure loads were higher in the PLS 1 group than in the PLS 2 group, but stiffness did not differ significantly between groups. All constructs failed by plate bending, with greater deformation in the PLS 2 group. Push-out force to screw-plate uncoupling was higher in the PLS 2 group than in the PLS 1 group for uncontoured and contoured plates. Locking mechanism failure of PLS 1 specimens was through screw-thread stripping. The PLS 2 specimens failed by node deformation followed by screwhead stripping. CONCLUSIONS AND CLINICAL RELEVANCE: Distinct mechanical differences were identified between the 2 PLSs. The clinical relevance of these differences is unknown. Further research including cyclic fatigue testing is needed to reveal more clinically pertinent information.


Assuntos
Placas Ósseas , Parafusos Ósseos , Animais , Fenômenos Biomecânicos , Estresse Mecânico
9.
Case Rep Vet Med ; 2018: 2976795, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29955434

RESUMO

The Minimally Invasive Reduction Instrumentation System (MIRIS) was utilized to facilitate minimally invasive plate osteosynthesis (MIPO) of distal limb diaphyseal comminuted fractures (2 crural, 1 antebrachial) in three dogs. The MIRIS facilitated efficient MIPO in all three fractures. Radial and tibial lengths were restored within 2% of the length of the intact bone and postoperative frontal and sagittal plane angulation were within 3° of the normal contralateral limb for each of the fractures. Fixation failed in one of the tibial fractures when the plates bent a week following surgery. The implants were removed and the fracture was restabilized via MIPO facilitated by the MIRIS. Inappropriate implant selection was considered the primary reason for implant failure. All three fractures achieved union by 10 weeks following surgery. The dog that underwent revision surgery developed a surgical site infection 5 months following revision surgery, which necessitated implant removal. All three dogs had excellent limb function at the time of the final evaluation. This system resulted in reductions that were near anatomic, with acceptable restoration of length and alignment and excellent limb function.

10.
BMC Vet Res ; 14(1): 164, 2018 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-29784034

RESUMO

BACKGROUND: Bone healing and assessment of the state of bone bridging is an important part of clinical orthopedics, whether for fracture healing or for follow up of osteotomy procedures. Tibial tuberosity advancement (TTA) is designed to restore stability in cruciate deficient stifle joints by advancing the tuberosity while creating an osteotomy gap. The current study aims to: 1) compare three different imaging modalities to assess bone healing: ultrasound, radiographs and computed tomography (CT) and, to 2) compare the effect of a gelatinous matrix (GM) versus a demineralized bone matrix mix (DBM mix) on bone healing and bridging of this osteotomy gap in 10 otherwise healthy client-owned dogs with cranial cruciate ligament insufficiency. Osseous union of the osteotomy gap was evaluated with ultrasound, radiographs and CT at one, two, and 3 months postoperatively. Dogs were randomly selected to receive GM or DBM mix to fill the osteotomy gap created during the TTA procedure. Bone healing was assessed subjectively on all modalities as well as scored on radiographs and measured using Hounsfield units (HUs) on CT. Time to heal based on ultrasound, radiographs and CT were statistically compared between groups with significance set at p < 0.05. RESULTS: All osteotomy gaps were bridged with bone within 3 months for all modalities. Bridging bone was diagnosed in 5.6 weeks, 10.4 weeks and 9.6 weeks based on ultrasound, radiographs, and CT, respectively, in dogs treated with DBM mix. In dogs treated with GM osseous union was diagnosed in a mean of 4.0 weeks, 9.6 weeks and 7.2 weeks based on ultrasound, radiographs and CT. Ultrasound diagnosed osseous union significantly faster than both CT and radiographs (p < 0.001). The dimensions of the newly formed bone differed between treatment groups with the central portion of the bone only providing a small bridge in GM cases. Although bridging of the osteotomy gap occurred earlier in the group that received GM, no significant statistical difference was found between the two groups. CONCLUSIONS: Radiographs overestimate the time needed for osseous union of the osteotomy gap. All osteotomy sites healed radiographically within 3 months.


Assuntos
Lesões do Ligamento Cruzado Anterior/veterinária , Desenvolvimento Ósseo , Cães/lesões , Tíbia/cirurgia , Animais , Ligamento Cruzado Anterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/cirurgia , Lesões do Ligamento Cruzado Anterior/terapia , Osseointegração , Osteotomia/veterinária , Projetos Piloto , Radiografia/veterinária , Joelho de Quadrúpedes/diagnóstico por imagem , Joelho de Quadrúpedes/lesões , Joelho de Quadrúpedes/cirurgia , Tíbia/diagnóstico por imagem , Tomografia Computadorizada por Raios X/veterinária , Ultrassonografia/veterinária
11.
J Zoo Wildl Med ; 49(1): 162-171, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29517460

RESUMO

The clinical outcomes of six free-ranging Florida panthers ( Puma concolor coryi) that underwent surgical stabilization of appendicular long-bone fractures (three femoral fractures, one tibial and one tibial and fibular fracture and two radial and ulnar fractures) were evaluated. These panthers presented to the University of Florida from 2000-2014. Estimated age of the panthers ranged from 0.5 to 4.5 yr, and weights ranged from 22 to 65 kg. Causes of injuries were vehicular collision ( n = 4) and capture related ( n = 2). All panthers underwent open reduction and fracture stabilization. Fixation failure necessitated three subsequent surgeries in one panther. Five panthers survived the immediate postoperative period, and all of these panthers' fractures obtained radiographic union (range, 8-36 [mean, 22] wk). The five surviving panthers underwent convalescence for 7-14 mo at White Oak Conservation Center before being released back into the wild; however, one panther was killed when hit by a car 3 days after release. The remaining four panthers were tracked for up to 106 mo in the wild and successfully integrated back into the native population. Surgical stabilization of appendicular long-bone fractures in free-ranging Florida panthers can be successful, but must take into account the stress that a large, undomesticated felid will place on the stabilized limb during convalescence as well as the difficulties involved in rehabilitating a wild panther in captivity.


Assuntos
Fixação Interna de Fraturas/veterinária , Fraturas Ósseas/veterinária , Puma , Animais , Feminino , Florida , Fixação Interna de Fraturas/instrumentação , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/cirurgia , Masculino , Puma/lesões , Puma/cirurgia
12.
BMC Vet Res ; 14(1): 85, 2018 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-29530093

RESUMO

BACKGROUND: Cranial cruciate ligament (CrCL) insufficiency is a degenerative condition that is a common cause of pelvic limb lameness and osteoarthritis in dogs. Surgical therapies developed to treat dogs with naturally occurring CrCL insufficiency aim to address the resultant instability, but the in-vivo alterations in stifle kinematics associated with CrCL insufficiency have not been accurately defined. The objective of this study was to quantify the 3-dimensional femorotibial joint kinematics of dogs with naturally occurring cranial cruciate ligament (CrCL) insufficiency during ambulation. Eighteen client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Computed tomographic scans were used to create digital 3-dimensional models of the femur and tibia bilaterally for each dog. Lateral fluoroscopic images were obtained during treadmill walking and 3 complete gait cycles were analyzed. Stifle flexion/extension angle, craniocaudal translation, and internal/external rotation were calculated throughout the gait cycle using a previously described 3D-to-2D image registration process. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative contralateral stifles (control). RESULTS: CrCL-deficient stifles were maintained in greater flexion throughout the gait cycle. Cranial tibial subluxation was evident in CrCL-deficient stifles at all time points throughout the gait cycle [9.7 mm at mid-stance (P < 0.0001); 2.1 mm at mid-swing (P < 0.0017)], and the magnitude of cranial tibial subluxation was greater at mid-stance phase than at mid-swing phase (P < 0.0001). Greater internal tibial rotation was present in CrCL-deficient stifles during stance phase (P < 0.0022) but no difference in axial rotation was evident during swing phase. CONCLUSIONS: Naturally occurring CrCL rupture causes profound craniocaudal translational and axial rotational instability, which is most pronounced during the stance phase of gait. Surgical stabilization techniques should aim to resolve both craniocaudal subluxation and axial rotational instability.


Assuntos
Ligamento Cruzado Anterior/diagnóstico por imagem , Doenças do Cão/diagnóstico por imagem , Fêmur/diagnóstico por imagem , Artropatias/veterinária , Tíbia/diagnóstico por imagem , Animais , Ligamento Cruzado Anterior/fisiopatologia , Fenômenos Biomecânicos , Doenças do Cão/fisiopatologia , Cães , Feminino , Fêmur/fisiopatologia , Fluoroscopia/métodos , Fluoroscopia/veterinária , Imagem Tridimensional/métodos , Imagem Tridimensional/veterinária , Artropatias/diagnóstico por imagem , Artropatias/fisiopatologia , Masculino , Joelho de Quadrúpedes/diagnóstico por imagem , Joelho de Quadrúpedes/fisiopatologia , Tíbia/fisiopatologia , Caminhada/fisiologia
13.
ACS Synth Biol ; 7(1): 107-120, 2018 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-29113433

RESUMO

Living cells are known for their capacity for versatile signal processing, particularly the ability to respond differently to the same stimuli using biochemical networks that integrate environmental signals and reconfigure their dynamic responses. However, the complexity of natural biological networks confounds the discovery of fundamental mechanisms behind versatile signaling. Here, we study one specific aspect of reconfigurable signal processing in which a minimal biological network integrates two signals, using one to reconfigure the network's transfer function with respect to the other, producing an emergent switch between induction and repression. In contrast to known mechanisms, the new mechanism reconfigures transfer functions through genetic networks without extensive protein-protein interactions. These results provide a novel explanation for the versatility of genetic programs, and suggest a new mechanism of signal integration that may govern flexibility and plasticity of gene expression.


Assuntos
Modelos Biológicos , Transdução de Sinais/genética , Fator de Transcrição AraC/genética , RNA Polimerases Dirigidas por DNA/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Isopropiltiogalactosídeo/farmacologia , Plasmídeos/genética , Plasmídeos/metabolismo , Regiões Promotoras Genéticas , Proteínas Virais/genética
14.
Cell Mol Bioeng ; 11(5): 367-382, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31719890

RESUMO

Introduction: Microbes aggregate when they display adhesive proteins on their outer membrane surfaces, which then form bridges between microbes. Aggregation protects the inner microbes from harsh environmental conditions such as high concentrations of antibiotics, high salt conditions, and fluctuations in pH. The protective effects of microbial aggregation make it an attractive target for improving the ability of probiotic strains to persist in the gut environment. However, it remains challenging to achieve synthetic microbial aggregation using natural adhesive proteins because these proteins frequently mediate microbial virulence. Objectives: Construction of synthetic proteins that mediate aggregation between microbes to enhance the survival of cells delivered to stressful environments. Methods: We construct synthetic adhesins by fusing adhesive protein domains to surface display peptides. The resulting aggregated populations of bacteria are characterized using immunofluorescence, microscopy, flow cytometry, and quantification of colony forming units. Results: We assemble a series of synthetic adhesins, demonstrate their display on the outer membrane of Escherichia coli, and show that they mediate bacterial aggregation. Further engineering of the size and motif composition of the adhesive domain shows that principles from natural adhesins can be applied to our synthetic adhesins. Finally, we show that aggregation allows E. coli cells to resist treatment with antimicrobial peptides and survive inside the gut of Caenorhabditis elegans. Conclusions: Our results demonstrate that synthetic aggregation can allow bacteria to resist biocidal environmental conditions. Synthetic adhesins may be used to facilitate microbial colonization of previously inaccessible environmental niches, either in remote natural environments or inside living organisms.

15.
Biotechnol J ; 13(5): e1700167, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29149479

RESUMO

Reducing leaky gene expression is critical for improving protein yield of recombinant bacteria and stability of engineered cellular circuits in synthetic biology. Leaky gene expression occurs when a genetic promoter is not fully repressed, leading to unintended protein synthesis in the absence of stimuli. Existing work have devised specific molecular strategies for reducing leaky gene expression of each promoter. In contrast, we describe a repurposed, modular CRISPRi system that attenuates leaky gene expression using a series of single-guide RNAs targeting the PT7/LacO1 promoter. Furthermore, we demonstrate the efficacy of CRISPRi to significantly increase the dynamic range of T7 RNA Polymerase (T7RNAP) promoters. In addition, we demonstrate that the CRISPRi system can be applied to enhance growth of bacteria that suffer from leaky expression of a toxic protein. Our work establishes a new application of CRISPRi in genomic engineering to improve the control of recombinant gene expression. The approach is potentially generalizable to other gene expression system by changing the single-guide RNAs.


Assuntos
Sistemas CRISPR-Cas , RNA Polimerases Dirigidas por DNA , Regiões Promotoras Genéticas , Biologia Sintética , Proteínas Virais , Edição de Genes , Expressão Gênica
16.
Nat Biomed Eng ; 2(2): 58-59, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-31015622
17.
Can Vet J ; 58(11): 1176-1180, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29089654

RESUMO

Two dogs with spontaneous luxation of the long digital extensor tendon of origin were managed by performing a sulcoplasty and applying a plate bridging the extensor sulcus. Lameness resolved and neither dog had recurrence of lameness 59 and 15 months following surgery.


Assuntos
Placas Ósseas/veterinária , Cães/lesões , Traumatismos dos Tendões/veterinária , Tíbia/cirurgia , Animais , Cães/cirurgia , Feminino , Membro Posterior , Coxeadura Animal/etiologia , Masculino , Osteotomia/veterinária , Traumatismos dos Tendões/complicações , Traumatismos dos Tendões/diagnóstico , Traumatismos dos Tendões/cirurgia
18.
Vet Surg ; 46(7): 971-980, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28703857

RESUMO

OBJECTIVE: To compare the Minimally Invasive Reduction Instrumentation System (MIRIS) to a two-ring circular fixator construct (CFC) for indirect reduction during minimally invasive plate osteosynthesis. STUDY DESIGN: Cadaveric antebrachial fracture model. ANIMALS: Ten skeletally mature dog cadavers. METHODS: Simulated bilateral antebrachial fractures were reduced and stabilized with the MIRIS on one limb, and a CFC on the contralateral limb, prior to placing a 10 hole Locking Compression Plate. Time to satisfactory reduction and implant placement were compared. Difficulty of fracture reduction and plate application was subjectively scored (1 to 5) for each procedure. Prefracture and postoperative orthogonal antebrachial radiographs were compared to assess restoration of radial length and angulation in sagittal and frontal planes. A paired t test (P ≤ .05) was used to compare parameters between the two reduction techniques. RESULTS: Reduction was faster (P = .0191) and plate application was subjectively easier (P = .047) when using the MIRIS compared to the CFC. There were no differences in subjective difficulty of reduction or plate application time between techniques. Mean postoperative radial length was reduced by approximately 4-mm, and procurvatum were decreased by approximately 7° compared to prefracture measurements, regardless of reduction technique. CONCLUSION: The MIRIS allowed for faster fracture reduction, and simplified plate placement compared to a temporary application of a CFC in our simulated antebrachial fracture model.


Assuntos
Placas Ósseas/veterinária , Cães , Fixadores Externos/veterinária , Fixação Interna de Fraturas/veterinária , Fixação de Fratura/veterinária , Animais , Cadáver , Fixação de Fratura/métodos , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/cirurgia , Fraturas Ósseas/veterinária , Procedimentos Cirúrgicos Minimamente Invasivos/veterinária , Radiografia
19.
Vet Surg ; 46(7): 933-941, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28640455

RESUMO

OBJECTIVE: To compare the biomechanical properties of using an interfragmentary 1.6 mm Kirschner wire or a 2.7 mm reconstruction plate as adjunctive epicondylar stabilization in simulated comminuted lateral unicondylar humeral fractures stabilized with a transcondylar 4.5 mm cortical screw. STUDY DESIGN: Cadaveric biomechanical assessment. SAMPLE POPULATION: Paired humeri harvested from 9 young, skeletally mature dogs. METHODS: Simulated comminuted lateral unicondylar humeral fractures were stabilized with a transcondylar 4.5 mm cortical screw placed in lag fashion. Adjunct fixations consisting of a 1.6 mm Kirschner wire on one side, and a 2.7 mm reconstruction plate on the contralateral side, were tested within paired humeri. Repaired humeri were axially loaded to failure and construct stiffness, yield load, and load to failure were obtained from the load-deformation curves. RESULTS: Stiffness (mean ± SD: 577 ± 245 vs 310 ± 71 N/mm; P = .01), yield load (mean ± SD: 2389 ± 572 vs 1017 N ± 292; P = .0002), and load at failure (mean ± SD: 3351 ± 358 vs 1693 ± 363 N; P = .009) were greater in constructs incorporating a reconstruction plate rather than a Kirschner wire. CONCLUSION: Our results support the recommendation for adjunct fixation of comminuted lateral unicondylar humeral fractures with an epicondylar plate.


Assuntos
Placas Ósseas/veterinária , Parafusos Ósseos/veterinária , Fios Ortopédicos/veterinária , Fixação Interna de Fraturas/instrumentação , Fixação Interna de Fraturas/veterinária , Fraturas do Úmero/cirurgia , Animais , Fenômenos Biomecânicos , Cadáver , Cães , Fixação Interna de Fraturas/métodos , Fraturas Cominutivas/cirurgia , Fraturas Cominutivas/veterinária
20.
Am J Vet Res ; 78(6): 712-717, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28541152

RESUMO

OBJECTIVE To compare stiffness and resistance to cyclic fatigue of two 3.5-mm locking system plate-rod constructs applied to an experimentally created fracture gap in femurs of canine cadavers. SAMPLE 20 femurs from cadavers of 10 mixed-breed adult dogs. PROCEDURES 1 femur from each cadaver was stabilized with a conical coupling plating system-rod construct, and the contralateral femur was stabilized with a locking compression plate (LCP)-rod construct. An intramedullary Steinmann pin was inserted in each femur. A 40-mm gap then was created; the gap was centered beneath the central portion of each plate. Cyclic axial loading with increasing loads was performed. Specimens that did not fail during cyclic loading were subjected to an acute load to failure. RESULTS During cyclic loading, significantly more LCP constructs failed (6/10), compared with the number of conical coupling plating system constructs that failed (1/10). Mode of failure of the constructs included fracture of the medial or caudal aspect of the cortex of the proximal segment with bending of the plate and pin, bending of the plate and pin without fracture, and screw pullout. Mean stiffness, yield load, and load to failure were not significantly different between the 2 methods of stabilization. CONCLUSIONS AND CLINICAL RELEVANCE Both constructs had similar biomechanical properties, but the conical coupling plating system was less likely to fail than was the LCP system when subjected to cyclic loading. These results should be interpreted with caution because testing was limited to a single loading mode.


Assuntos
Placas Ósseas/veterinária , Cães/lesões , Fraturas do Fêmur/veterinária , Fixação Interna de Fraturas/veterinária , Animais , Fenômenos Biomecânicos , Parafusos Ósseos/veterinária , Cadáver , Cães/cirurgia , Fraturas do Fêmur/cirurgia , Fêmur/cirurgia
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