A rabbit model of tracheal collapse for optimal self-expanding metal stents.

Investigating the characteristics of tracheas can help the understanding of diseases related to the trachea, particularly tracheal collapse (TC) in dogs. This study aimed to compare the mechanical properties of tracheas from New Zealand White (NZW) rabbits and dogs and to introduce a method for inducing a model of TC in the normal trachea. Tracheal samples were obtained from NZW rabbit cadavers (n=5) weighing 3.62-3.92 kg and from dog cadavers (n=5) weighing 2.97-3.28 kg. Three live NZW rabbits weighing 3.5-4.0 kg were used to establish the model. The radial forces of both sample sets were measured using a digital force gauge and statistically compared. Subsequently, TC was surgically induced in three female NZW rabbits by physically weakening their tracheal cartilage under general anesthesia. Their clinical signs were monitored for 3 months, and radiographic examinations were performed monthly for 3 months. The mean radial forces of the two sample sets were comparable (P>0.05). The clinical signs, radiographic examinations, and macroscopic examinations were all comparable to those of dogs with TC. The cadaveric study between the rabbits and dogs demonstrated that the surgically induced rabbit model of TC is an excellent candidate for the experimental study of dogs with TC. This study also provides a reference of tracheal radial force values to enable selection of appropriate mesh types and wire diameters of self-expanding metal stents.

Surgical outcomes in dogs with tracheal collapse treated with a novel cross-and-hook braided endoluminal stent.

BACKGROUND: Stenting is an effective treatment option for tracheal collapse in dogs. Cross-braided tracheal stents are currently the norm in veterinary medicine, but cross-and-hook braided stents have recently been adopted in human medicine. We examined whether stents manufactured using this novel braiding technique provided additional advantages for the treatment of tracheal collapse in dogs. OBJECTIVES: To evaluate the outcomes of cross-and-hook braided stent implantation in the treatment of tracheal collapse in dogs. METHODS: The medical records of 22 client-owned dogs that underwent luminal placement of cross-and-hook braided Fauna Stents for the treatment of tracheal collapse between January 2018 and July 2021 were examined and data on canine signalment, clinical signs, diagnostic test results, surgical outcomes, and postoperative complications were retrieved and analyzed statistically. RESULTS: Twenty-six stents were surgically implanted, with 20 dogs (90.9%) receiving one stent and the remaining two (9.1%) receiving two or more stents. All dogs survived the procedure. The median survival time at a median follow-up of 990 days was 879 days. At the final follow-up examination, loss or mild improvement of cough was observed in all dogs. CONCLUSIONS: Compared with conventional lumen stents, the cross-and-hook braided Fauna Stent offered a higher survival rate and improved clinical symptoms in all patients. The results of this study suggest that the Fauna Stent may be a promising treatment option for dogs with tracheal collapse.

Osseodensification enables bone healing chambers with improved low-density bone site primary stability: an in vivo study.

Primary implant stability is a prerequisite for successful implant osseointegration. The osseodensification technique (OD) is a non-subtractive drilling technique that preserves the bone tissue, increases osteotomy wall density, and improves the primary stability. This study aimed to investigate the hypothesis that OD, through a wider osteotomy, produces healing chambers (HCs) at the implant-bone interface without impacting low-density bone primary stability. Twenty implants (3.5 × 10 mm) with a nanohydroxyapatite (nHA) surface were inserted in the ilium of ten sheep. Implant beds were prepared as follows: (i) 2.7-mm-wide using subtractive conventional drilling (SCD) technique (n = 10); (ii) 3.8-mm-wide using an OD bur system (n = 10). The sheep were randomized to two groups, with samples collected at either 14-(n = 5) or 28-days (n = 5) post-surgery and processed for histological and histomorphometric evaluation of bone-implant contact (BIC) and bone area fraction occupancy (BAFO). No significant group differences were found with respect to final insertion torque and implant stability quotient (p > 0.050). BIC values were higher for SCD after 14 and 28 days (p < 0.050); however, BAFO values were similar (p > 0.050). It was possible to conclude that the OD technique allowed a wider implant bed preparation without prejudice on primary stability and bone remodeling.

Comparison of short-, intermediate-, and long-term results between dogs with tracheal collapse that underwent multimodal medical management alone and those that underwent tracheal endoluminal stent placement.

OBJECTIVE: To compare short-, intermediate-, and long-term results between dogs with tracheal collapse (TC) that received multimodal medical management only and those that underwent tracheal endoluminal stent placement. ANIMALS: 159 dogs with TC that underwent medical management only (MM group; n = 84) or were surgically managed by stent placement (SM group; 75). PROCEDURES: Medical records of dogs with TC that underwent medical management only or stent placement at a referral hospital between September 1, 2009, and August 1, 2018, were reviewed. Data regarding signalment, information relevant to TC, and outcome were extracted from the records and aggregated into short-, intermediate-, and long-term follow-up periods for analysis. Descriptive data and median survival times (MSTs) were compared between the MM and SM groups. RESULTS: Clinical signs of dogs in the MM group generally improved during the short term but regressed and worsened over time. The proportion of dogs with malformation-type TC that underwent stent placement (38/43 [88%]) was significantly greater than the proportion of dogs with traditional-type TC that underwent stent placement (37/107 [35%]). The MST from TC diagnosis was 3.7 years for the MM group and 5.2 years for the SM group. For dogs with severe disease, the MST was 12 days for medically managed dogs and 1,338 days for dogs that underwent stent placement. CONCLUSIONS AND CLINICAL RELEVANCE: Multimodal medical management alleviated clinical signs for months to years in dogs with mild to moderate TC disease, but stent placement should be considered for dogs with severe disease.

Custom-made artificial eyes using 3D printing for dogs: A preliminary study.

Various incurable eye diseases in companion animals often result in phthisis bulbi and eye removal surgery. Currently, the evisceration method using silicone balls is useful in animals; however, it is not available to those with impaired cornea or severe ocular atrophy. Moreover, ocular implant and prostheses are not widely used because of the diversity in animal size and eye shape, and high manufacturing cost. Here, we produced low-cost and customized artificial eyes, including implant and prosthesis, using computer-aided design and three-dimensional (3D) printing technique. For 3D modeling, the size of the artificial eyes was optimized using B-mode ultrasonography. The design was exported to STL files, and then printed using polycaprolactone (PCL) for prosthesis and mixture of PCL and hydroxyapatite (HA) for ocular implant. The 3D printed artificial eyes could be produced in less than one and half hour. The prosthesis was painted using oil colors and biocompatible resin. Two types of eye removal surgery, including evisceration and enucleation, were performed using two beagle dogs, as a preliminary study. After the surgery, the dogs were clinically evaluated for 6 months and then histopathological evaluation of the implant was done. Ocular implant was biocompatible and host tissue ingrowth was induced after in vivo application. The custom-made prosthesis was cosmetically excellent. Although long-term clinical follow-up might be required, the use of 3D printed-customized artificial eyes may be beneficial for animals that need personalized artificial eye surgery.

Correlations among tracheal dimensions, tracheal stent dimensions, and major complications after endoluminal stenting of tracheal collapse syndrome in dogs.

BACKGROUND: Endoluminal tracheal stenting can relieve signs associated with tracheal collapse syndrome (TCS) in dogs, but major complications can result. OBJECTIVE: To identify associations among tracheal dimensions, stent dimensions, and subsequent complications requiring additional stent placement after endoluminal stenting for TCS. ANIMALS: Fifty-two dogs from the hospital population. METHODS: Medical records of dogs that received an endoluminal self-expanding tracheal stent for TCS by the interventional radiology service between 2009 and 2014 were reviewed for relevant data. Signalment and clinical details, including tracheal collapse type, tracheal measurements, nominal stent dimensions, follow-up evaluation times, and stent complications, were recorded. RESULTS: Fifty-two dogs that received an endoluminal stent for TCS met the inclusion criteria. Major complications included stent fracture (13/52; 25%), obstructive tissue ingrowth (10/52; 19%), and progressive tracheal collapse (6/52; 12%). Natural tracheal taper (P = .04) and more stent diameter oversizing (P = .04) in the intrathoracic (IT) trachea were associated with caudodorsal stent fracture. Only stents with a 14-mm nominal diameter fractured. Progressive tracheal collapse was associated with smaller maximum tracheal diameters (P = .02). The majority of dogs with obstructive tissue ingrowth (7/10; 70%; P = .30) and all dogs with thoracic inlet fractures (3/3; 100%) had tracheal malformations. CONCLUSIONS AND CLINICAL IMPORTANCE: A higher taper in tracheal diameter may lead to increased risk of fracture in the IT location. Dogs with tracheal malformations may have higher risk for thoracic inlet fracture and development of obstructive tissue ingrowth. Clinicians should be aware of the possible risk factors for tracheal stent complications.

Long-term outcomes of 54 dogs with tracheal collapse treated with a continuous extraluminal tracheal prosthesis.

OBJECTIVE: To describe the surgical placement of a continuous extraluminal tracheal prosthesis (CETP) and report the subsequent postoperative clinical outcomes in dogs with tracheal collapse. STUDY DESIGN: Retrospective case series. ANIMALS: Fifty-four dogs. METHODS: Medical records of dogs in which cervical and/or thoracic inlet tracheal collapse was diagnosed and treated by placement of a CETP between 2010 and 2017 were reviewed to evaluate postoperative complications, changes in respiratory function, and survival. Histological examinations of tracheal tissues performed in 2 dogs at 51 and 57 months after surgery were also reviewed. RESULTS: Fifty-three (98%) dogs survived to discharge. Postoperative complications included laryngeal paralysis (1 dog), disseminated intravascular coagulation (1 dog), and recurrent tracheal collapse (2 dogs). None of the dogs exhibited clinical evidence of tracheal necrosis. Preoperative dry, harsh cough resolved in 87% of the dogs after surgery. Goose honking cough was resolved in 25 of 26 (96%) dogs. Median follow-up time was 30 months (range, 16 days to 76 months). The survival rate at 36 months was 86% (CI: 75%-96%). On histological examination in 2 dogs, the tracheal tissue surrounding the prosthesis was well preserved and without evidence of chronic inflammation. CONCLUSION: Continuous extraluminal tracheal prosthesis placement in dogs with tracheal collapse resulted in low postoperative complication rates and good long-term outcomes. CLINICAL SIGNIFICANCE: Continuous extraluminal tracheal prosthesis placement provides a viable alternative surgical option for managing dogs with tracheal collapse.

Short-, intermediate-, and long-term results for endoluminal stent placement in dogs with tracheal collapse.

OBJECTIVE To evaluate outcomes following endoluminal stent placement for treatment of tracheal collapse (TC) in dogs. DESIGN Retrospective case series with nested observational study. ANIMALS 75 dogs that underwent endoluminal placement of a self-expanding metallic stent to treat TC between September 2009 and August 2015. PROCEDURES Medical records were reviewed to collect data on dog characteristics, clinical signs, TC type, diagnostic test results, peri- and postoperative complications, and outcomes. Complication rates and survival times and rates were compared between various groups. RESULTS The 75 dogs received 119 stents (56% [42/75] received 1 stent and 44% [33/75] received ≥ 2 stents). Thirty-eight (51%) dogs had a malformation type of TC, and 37 (49%) had the traditional type. Ninety-three percent (70/75) of dogs survived to hospital discharge. Median survival time was 1,005 days. Improvement in goose-honking or raspy breathing (89% [42/47]) and dyspnea (84% [43/51]) was reported at final follow-up examination. Major complications requiring additional stent placement procedures occurred in 47% (33/70) of dogs over the follow-up period; stent fracture and tissue ingrowth were the most common types. Male dogs and younger dogs had a significantly longer survival time than other dogs. Mainstem bronchial collapse at the time of stent placement had no significant association with outcome. CONCLUSIONS AND CLINICAL RELEVANCE Endoluminal stent placement provided a high survival rate for dogs with TC, even those with severe clinical signs. This information, as well as the information on potential complications, should be useful for advising owners of affected dogs.

Outcomes of horses treated with removal of a laryngoplasty prosthesis.

OBJECTIVE: To determine the proportion of horses treated by laryngoplasty prosthesis removal (LPR) for complications associated with prosthetic laryngoplasty (LP), the reason for LPR, and the outcome of horses undergoing LPR to manage iatrogenic coughing/dysphagia. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Client-owned horses treated with LP (n = 1202) and LPR (n = 58). METHODS: Clinical case records were reviewed to determine the number of horses treated with LP and LPR by the same surgeon. Historical, clinical, endoscopic, and surgical data were extracted for those horses undergoing LPR. Long-term outcome was assessed by questionnaire. RESULTS: The proportion of horses treated with LP and subsequently treated with LPR by the same surgeon was 3.5% (42/1202). Coughing/dysphagia was the reason for LPR in 90% (52/58) of horses. Sufficient follow-up to determine outcome in horses undergoing LPR for coughing/dysphagia was available in 32 horses. Arytenoid abduction grade at the time of LPR did not influence clinical response (P = .416). Presenting clinical signs resolved after LPR in 21 of 32 (66%) horses, and 24 of 32 (75%) horses returned to exercise. CONCLUSION: Coughing/dysphagia was the most common reason for LPR. Clinical signs improved in most horses after LPR. CLINICAL SIGNIFICANCE: Laryngoplasty prosthesis removal can be a useful treatment option for horses affected with unmanageable coughing/dysphagia caused by LP.

Interventional Management of Urethral Obstructions.

Lower urinary tract (LUT) emergencies are common reasons for small animal patients to be presented to their veterinarians. Patient stabilization and management of life threatening problems is a priority in this population. Urethral obstruction is a common LUT emergency. Urethral stent placement has gained popularity over the past decade allowing for a minimally invasive, image-guided method for relief of urethral obstruction in some patient populations. This article focuses on candidate selection, diagnostic workup, stent placement technique, and the expected outcome and complications for patients undergoing urethral stent placement and addresses some additional strategies for interventional management of LUT emergencies.

A retrospective review of 146 active and passive fixation bradycardia lead implantations in 74 dogs undergoing pacemaker implantation in a research setting of short term duration.

BACKGROUND: Canine veterinary patients increasingly benefit from implantation of transvenous pacemakers for bradyarrhythmias. No published data exist examining procedural outcomes of pacemaker implantation performed in the preclinical laboratory. The purpose was to review short term complication, infection, dislodgement, penetration rates, plus overall morbidity following pacemaker implantation in the research setting. A retrospective review of 74 Class A purpose-bred mongrels implanted with active (n = 89) and passive fixation (n = 57) intracardiac leads for dual (n = 72) or single (n = 2) chamber pacing was performed. RESULTS: All leads were implanted successfully, meeting electrical implant criteria. Follow-ups typically occurred every 7 days (first month), then at 30 day intervals. Seroma formation was 1.4% and 10.8% at the venotomy and pulse generator site respectively. Overall infection rate was 1.4%. Overall dislodgement rate was 2.1%, (2 passive atrial leads, 1 passive ventricular lead). Overall fractures and insulation defects were zero. Two helix penetrations were noted incidentally post mortem, one at the right atrial appendage and one at the right ventricle (64 dogs, 128 leads evaluated), a 1.6% event rate. Major in-life adverse events were 5.4% (4 of 74 dogs), including 1 infection and 3 lead dislodgements. CONCLUSIONS: This review demonstrates a low complication rate with bradycardia lead implants in the short term (up to 180 days), in a high volume research setting. Lead type, implant technique, surgeon experience, healthy patient population, patient size and follow-up care play a role. This review also suggests active fixation leads in the right atrial appendage of dogs are safe and reliable.

Comparison of diode laser trans-scleral cyclophotocoagulation versus implantation of a 350-mm2 Baerveldt glaucoma drainage device for the treatment of glaucoma in dogs (a retrospective study: 2010-2016).

OBJECTIVE: To compare outcomes following trans-scleral cyclophotocoagulation (TSCP) and 350-mm2 Baerveldt implantation in the treatment of canine refractory glaucoma. DESIGN: Retrospective case study. CASE SELECTION: Client owned dogs undergoing surgical treatment of glaucoma within a veterinary referral hospital. PROCEDURES: Eighty-six glaucoma surgeries were performed on 83 eyes (69 dogs) diagnosed with primary or secondary glaucoma. Medical records were retrieved, and baseline data, surgery, medications, intraocular pressures (IOPs), vision, and complications were extracted. RESULTS: Fifty-four eyes (44 dogs) were treated with TSCP and placement of an anterior chamber suture shunt; 28 eyes (24 dogs) were implanted with a Baerveldt glaucoma drainage device (GDD); and four eyes (4 dogs) underwent GDD implantation after failure of TSCP to manage IOP. Following TSCP, IOP control (<20 mmHg) and vision retention occurred in 81.5% and 42.6%, respectively, for 16.1 ± 1.36 months. Following GDD implantation, 71.4% maintained IOP <20 mmHg and 69.6% maintained vision for 11.0 ± 0.94 months. IOP control without loss of vision was more likely following Baerveldt implantation (17/28; 60.7%) than TSCP (19/54; 35.2%) (P = 0.027). One eye had functional vision restored following GDD placement. IOP control without adjunctive medications was more likely following Baerveldt implantation (P = 0.02). CONCLUSIONS: In this study, eyes treated with Baerveldt GDD implantation were more likely to maintain IOP control and retain vision compared to eyes treated with TSCP and placement of an anterior chamber suture shunt. Lack of formal randomization, inconsistencies in surgical techniques and TSCP protocols, and potential unmeasured confounders must be considered when extrapolating from this retrospective study.

Immediate, short-, and long-term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome.

BACKGROUND: Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs. OBJECTIVES: Identify immediate post-stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate-, short-, and long-term periods, and evaluate inter-observer reliability of radiographic measurements. ANIMALS: Fifty client-owned dogs. METHODS: Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post-stent placement radiographic follow-up times. Radiographs were used to obtain pre-stent tracheal measurements and post-stent placement measurements. RESULTS: Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Ultimate mean follow-up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long-term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short-, or long-term periods. Good inter-observer agreement of radiographic measurements was found among observers of variable experience level. CONCLUSIONS AND CLINICAL IMPORTANCE: Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications.

Visual evoked potential in rabbits' eyes with subretinal implantation by vitrectomy of Okayama University-type retinal prosthesis (OURePTM).

Okayama University-type retinal prosthesis (OURePTM) is a photoelectric dye-coupled polyethylene film which generates electric potential in response to light and stimulates nearby neurons. This study aims to test surgical feasibility for subretinal film implantation and to examine functional durability of films in subretinal space. Dye-coupled films were implanted subretinally by vitrectomy in the right eye of normal white rabbits: 8 rabbits for 1 month and 8 rabbits for 6 months. The implanted films were removed by vitrectomy in 4 of these 8 rabbits in 1-month or 6-month implantation group. The films were also implanted in 4 rhodopsin-transgenic retinal dystrophic rabbits. Visual evoked potential was measured before film implantation as well as 1 or 6 months after film implantation, or 1 month after film removal. The films were successfully implanted in subretinal space of retinal detachment induced by subretinal fluid injection with a 38G polyimide tip. The retina was reattached by fluid-air exchange in vitreous cavity, retinal laser coagulation, and silicone oil injection. The ratios of P2 amplitudes of visual evoked potential in the implanted right eye over control left eye did not show significant changes between pre-implantation and post-implantation or post-removal (paired t-test). In Kelvin probe measurements, 4 pieces each of removed films which were implanted for 1 or 6 months showed proportional increase of surface electric potential in response to increasing light intensity. The film implantation was safe and implanted films were capable of responding to light.

Subretinal implantation of Okayama University-type retinal prosthesis (OURePTM) in canine eyes by vitrectomy.

Okayama University-type retinal prosthesis (OURePTM) is a photoelectric dye-coupled polyethylene film which generates electric potential in response to light and stimulates nearby neurons. This study aims to test surgical feasibility of subretinal implantation and functional durability of dye-coupled films in the subretinal space. The dye-coupled films were implanted subretinally by 25-gauge vitrectomy in the right eye of 11 normal beagle dogs: 2 dogs served for film removal after 5-month film implantation, 3 dogs for film removal after 3-month film implantation, 3 dogs for 3-month film implantation and pathological examination, and 3 dogs for sham surgery. The surface electric potential of the removed dye-coupled films in response to light was measured by the Kelvin Probe system. At surgery, rolled-up dye-coupled films in 5 × 5 mm square size could be inserted into subretinal space of retinal detachment induced by fluid injection with a 38-gauge polyimide tip. Retinal attachment was maintained by silicone oil injection in vitreous cavity. At autopsy, the retina in all dogs maintained the ganglion cell layer, inner and outer nuclear layers while it lost the outer segments in some part. All 5 sheets of removed dye-coupled films maintained the dye color. One sheet of the 5-month implanted film showed proportional increase of surface potential in response to increasing light intensity. Subretinal implantation of OURePTM by vitrectomy was technically feasible in canine eyes, and OURePTM maintained the function of generating light-evoked surface potential after 5 months in subretinal implantation.

Clinical outcomes of patient-specific porous titanium endoprostheses in dogs with tumors of the mandible, radius, or tibia: 12 cases (2013-2016).

OBJECTIVE To characterize the processes involved in and outcomes achieved with custom-designed patient-specific implants to provide functional replacement of skeletal structures in dogs with tumors of the mandible, radius, or tibia. DESIGN Prospective case series. ANIMALS 6 dogs with mandibular tumors, 5 with tumors of the distal aspect of the radius, and 1 with a tumor in the distal aspect of the tibia treated from June 2013 to September 2016 at 3 referral centers. PROCEDURES After tumor staging, implants were designed from patients' CT scans by means of various computer-aided design applications and printed by means of selective laser melting in titanium-6 aluminum-4 vanadium alloy. A cutting jig was created in thermoplastic to ensure each osteotomy was performed as planned. Following ostectomy, the implant was secured into the defect with screws of appropriate size and length. RESULTS Initial return to normal clinical function was good to excellent for 11 of the 12 dogs. However, major complications resulted in revision of the implant or amputation of the limb in 5 dogs, and at least 3 of these complications were considered a consequence of faulty implant design or manufacturing. Infection developed in 2 dogs and was successfully treated in 1 dog. The longest-surviving dog maintained good limb function for 2 years. CONCLUSIONS AND CLINICAL RELEVANCE This is the largest reported series of dogs managed with customized 3-D-printed titanium implants. The 3-D printing allowed complex and patient-specific 3-D geometries to be fabricated, enabling function-sparing treatment of bone cancer affecting multiple anatomic sites.

Comportamento biomecânico de diferentes placas de avanço da tuberosidade da tíbia em cães: estudo comparativo ex vivo / Biomechanical behavior of two different tibial tuberosity advancement plates in dogs: comparative ex vivo biomechanical study

Este é o primeiro estudo que compara o comportamento biomecânico de duas diferentes placas de avanço da tuberosidade tibial (ATT). Com o objetivo de minimizar a incidência de falhas de implante, foram realizados ensaios biomecânicos em 10 pares de membros pélvicos de cadáveres de cães. No membro pélvico direito, foi colocada placa de ATT fixa por garfo, e no membro pélvico esquerdo placa fixa por parafusos. Os ensaios foram realizados utilizando-se máquina universal de ensaios mecânicos Kratos(r), modelo KE3000, dotada de célula de carga de 3000N, com velocidade de ensaio de 20mm/min. O parâmetro força e os gráficos gerados foram gravados por meio de sistema de aquisição analógica TRACOMP-W95 (TRCV61285). A média da carga máxima até a falha foi de 128,70kg/F (mínimo 104,55kg/F e máximo 151,80kg/F) e de 141,99kg/F (mínimo 111,60kg/F e máximo 169,65kg/F) no grupo utilizando garfo e parafusos, respectivamente. O desvio-padrão dos grupos garfo e parafuso foi baixo, 12,99 e 17,21, respectivamente. Foi encontrada diferença significativa (P=0,03) entre as médias dos grupos. Com base nos resultados obtidos, conclui-se que existe diferença estatística significativa na resistência promovida entre as placas testadas, quando se observou que a placa fixa por parafusos promove maior resistência.(AU)

This is the first study to compare the biomechanical strength between the two different TTA plates. With the purpose of minimizing the incidence of implant failure, biomechanical tests were performed on 10 pairs of cadaveric hind limbs from dogs. The right hind limb of each dog was used as a model for the TTA plate fixed by fork, and the left pelvic limb was used as a model for the TTA plate fixed by screws. Tests were performed using a universal mechanical testing Kratos (r) machine, model KE 3000, equipped with a load cell of 3000N with a test speed of 20mm/min. The strength parameter and graphs generated were recorded via analog acquisition system TRACOMP-W95 (TRCV61285). The mean load to failure was 128.70kg/F (minimum 104.55kg and maximum 151.80kg/F) and 141.99kg/F (minimum 111.60kg/F and maximum 169.65kg/F) in the fork and screws groups respectively. The standard deviation of the fork and screws groups was low: 12.99 and 17.21 respectively. Significant difference (P= 0.03) between means of the groups was observed. From the results obtained it was concluded that there is a statistically significant difference in the resistance between plates and the plate fixed by screws promotes increased strength.(AU)

Dislodgement of a right atrial thrombus and subsequent pulmonary thromboembolism following tracheal stent deployment in a dog.

OBJECTIVE: To report the management of a dog that required 2 treatments with mechanical ventilation; firstly for severe tracheal collapse and secondly following deployment of a nitinol tracheal stent that immediately preceded a nonoxygen responsive pulmonary thromboembolism (PTE), suspected to have originated from the right atrium. CASE SUMMARY: A 9-year-old female spayed Shetland Sheepdog was presented for management of a gallbladder mucocoele. Pertinent history included iatrogenic hyperadrenocorticism and tracheal collapse. The dog became clinical for tracheal collapse following laparoscopic cholecystectomy. Thoracic radiographs revealed moderate to severe tracheal collapse at the level of the thoracic inlet. Arterial blood gas was consistent with hypoventilation and mechanical ventilation was instituted. Given the severity of tracheal collapse, self-expanding nitinol tracheal stent placement was elected. Immediately following tracheal stent placement, the dog developed nonoxygen responsive hypoxemia requiring mechanical ventilation. Additional diagnostic tests revealed changes consistent with a PTE and a large thrombus in the right atrium. The dog was humanely euthanized. NEW OR UNIQUE INFORMATION PROVIDED: Dislodgement of a preexisting atrial thrombus has not been described as a complication following tracheal stent deployment. Additionally, although PTE is frequently considered to be oxygen responsive, it may not be if the embolism is severe enough.

Canine tracheal collapse.

Tracheal collapse occurs most commonly in middle-aged, small breed dogs. Clinical signs are usually proportional to the degree of collapse, ranging from mild airway irritation and paroxysmal coughing to respiratory distress and dyspnoea. Diagnosis is made by documenting dynamic airway collapse with radiographs, bronchoscopy or fluoroscopy. Most dogs respond well to medical management and treatment of any concurrent comorbidities. Surgical intervention may need to be considered in dogs that do not respond or have respiratory compromise. A variety of surgical techniques have been reported although extraluminal ring prostheses or intraluminal stenting are the most commonly used. Both techniques have numerous potential complications and require specialised training and experience but are associated with good short- and long-term outcomes.

Comparison of Outcome After Use of Extra-Luminal Rings and Intra-Luminal Stents for Treatment of Tracheal Collapse in Dogs.

OBJECTIVE: To report short- and long-term complications and outcomes of dogs treated for tracheal collapse secondary to chondromalacia with extra-luminal rings (ELR) or intra-luminal stents (ILS). STUDY DESIGN: Retrospective cohort. SAMPLE POPULATION: Dogs with naturally occurring tracheal collapse (n = 103). METHODS: Medical records (2002-2012) of dogs diagnosed with tracheal collapse that had treatment with ELR (n = 73) or ILS (30) were reviewed. Demographic information, procedural information, complications, survival time, and subjective outcomes were recorded. Follow-up periods were defined as <730 days (short-term) and >730 days (long-term). RESULTS: Ninety-two percent of dogs undergoing ELR and 100% of dogs undergoing ILS survived to hospital discharge. ELR dogs were significantly younger (P = .009) and significantly fewer had main-stem bronchial collapse (P < .001). After accounting for effects of age and presence of main-stem bronchial collapse, there was no significant difference in median survival time between groups. Dogs with main-stem bronchial collapse (regardless of treatment type) had a shorter survival time than dogs without main-stem bronchial collapse. Major complications occurred in ELR (42%) and ILS dogs (43%). CONCLUSIONS: Both ELR and ILS are associated with high complication rates. Younger dogs and dogs without main-stem bronchial collapse had a longer survival time, regardless of treatment.