Reliability of fluoroscopic examination of nasopharyngeal dorsoventral dimension change in pugs and French bulldogs.

OBJECTIVE: To compare intra- and interobserver agreements in two-dimensional measurements of changes in nasopharyngeal dimensions during breathing in pugs and French bulldogs. STUDY DESIGN: Experimental randomized study. ANIMALS: A total of 20 French bulldogs and 16 pugs. METHODS: Four observers with different levels of experience measured the dorsoventral dimensions of the nasopharynx during inspiration and expiration on fluoroscopy videos. Measurements were performed at the maximal narrowing of the nasopharynx for the functional method and at the level of the tip of the epiglottis for the anatomically adjusted method. The intra- and interobserver agreements of the measurements, ratio of the dynamic nasopharyngeal change (ΔL), and grade of nasopharyngeal (NP) collapse (no, partial or complete) were evaluated. RESULTS: The functional method resulted in intraobserver correlation coefficients of 0.532 (p < .01) and 0.751 (p < .01) and interobserver correlation coefficients of 0.378 (p < .01) and 0.621 (p < .01) for NP collapse grade and ΔL, respectively. The anatomically adjusted method, 0.491 (p < .01) and 0.576 (p < .01) and 0.495 (p < .01) and 0.729 (p < .01) for NP collapse grade and ΔL, respectively, were being used. One observer (radiologist) achieved intraobserver correlation coefficients >0.9 for both methods. CONCLUSION: Fair interobserver agreement was found for NP collapse grade (functional method), moderate intra- and interobserver agreements were found for NP collapse grade and ΔL (both methods) while intraobserver agreement for ΔL was good (functional method). CLINICAL SIGNIFICANCE: Both methods seem repeatable and reproducible but only for experienced radiologists. The use of ΔL may offer higher repeatability and reproducibility than grade of NP collapse regardless of the method used.

Outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning.

OBJECTIVE: To report the outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning (FGNMP). STUDY DESIGN: Retrospective case series. ANIMALS: A total of 15 client owned dogs and two cats with 57 metabone fractures. METHODS: Description of FGNMP and reporting of the following data: signalment, pre- and postoperative radiographs, intramedullary pin diameter used, anesthesia, surgery and coaptation times, duration to normal weightbearing and bone union, postoperative care and complications. RESULTS: Median surgery time was 54 min (range: 26-99), median duration of coaptation was 14 days (range: 1-5 weeks), median time to normal weightbearing was 16 days (range: 2-45) and median time to bone union was 6 weeks (range: 4-12). All cases had at least 12 months of post-surgical follow-up with a median follow-up of 18 months (range: 12-70). No major complications occurred. Mild radiographic changes associated with subchondral bone sclerosis were noted on follow-up radiographs in 13/57 fractures. All cases returned to normal gait and full (15) or acceptable (2) function. CONCLUSION: In this study, FGNMP was an effective and safe technique for metabone fracture repair, requiring only short-term external coaptation in most patients. Time to bone union and return to normal function compared favorably to previously reported techniques. CLINICAL RELEVANCE: Fluoroscopically guided normograde metabone pinning provides an alternative technique for treatment of metabone fractures.

Fluoroscopically-assisted closed reduction and percutaneous fixation of sacroiliac luxations in cats using 2.4 mm headless cannulated compression screws: Description, evaluation and clinical outcome.

OBJECTIVE: To describe fluoroscopically-assisted closed reduction and percutaneous fixation of sacroiliac-luxation (SIL) in cats and report radiographic results and long-term functional outcomes. STUDY DESIGN: Retrospective clinical study. ANIMALS: Eleven cats. METHODS: Percutaneous fixation of 17 SILs in 11 cats was performed with 2.4 mm headless cannulated compression screws under fluoroscopic guidance. Luxation-reduction, screw placement and purchase within the sacral body, pelvic canal diameter ratio (PCDR) and hemipelvic canal width ratio (HCWR) were assessed on pre- and postoperative radiographs. Radiographic follow-up was performed to assess the same parameters when available. Long-term clinical outcome was evaluated with an owner questionnaire. Wilcoxon paired-test was performed for comparison. RESULTS: Mean age and bodyweight of the cats were 3.3 ± 2.6 years and 4.0 ± 0.82 kg, respectively. Nine cats presented with concurrent pelvic injuries. Median luxation-reduction was 94.1% (IQR = 13.9) and median screw-purchase within the sacral body was 73.3% (IQR = 17.0) immediately postoperatively. One screw exited the sacral body caudally. Upon 7-week radiographic follow-up, luxation-reduction (88.3%, IQR = 20.1) and screw-purchase (70.7%, IQR = 12.8) had decreased compared to immediately postoperatively (p = .008 and p = .013 respectively). Screw migration was not observed. PCDR and HCWR measured on postoperative radiographs indicated successful restoration of the pelvic canal width. Owners reported an excellent long-term functional outcome (mean postoperative time: 19 ± 5 months). CONCLUSION: Fluoroscopically-assisted closed reduction and fixation of feline SIL using 2.4 mm headless cannulated compression screws allowed good reduction and optimal screw purchase within the sacral body. An excellent functional outcome was reported. CLINICAL SIGNIFICANCE: Minimally invasive reduction and fixation with headless compression screws should be considered in cats with SIL.

Computed tomography and fluoroscopy versus radiographic guidance for internal fixation of simulated dorsomedial-plantarolateral central tarsal bone fractures in nonracehorses.

OBJECTIVE: The aim of this study was to assess screw placement in simulated dorsomedial-plantarolateral central tarsal bone (CTB) fractures using two imaging guidance techniques - computed tomography (CT) with fluoroscopy compared to digital radiography alone (DR). STUDY DESIGN: Experimental study. SAMPLE POPULATION: Equine cadaver hindlimbs (n = 10 pairs). METHODS: One tarsus per pair was randomly assigned to have a 4.5 mm cortical screw placed across the CTB using CT and fluoroscopy (CT/F group) or digital radiography alone (DR group). Postoperative CT was performed on all limbs. Variables related to marker placement, procedure time, and screw positioning were recorded and compared using a paired t-test for dependent means (p < .05). RESULTS: Time for marker placement was longer for the CT/F group (p = .001), with no difference in total procedure time (p = .12). CT/F was not superior to radiography alone (p > .05) for parameters related to screw positioning. Based on the 95% CI, there was greater range in relative screw length using radiography (76.5%-91.2%) versus CT/F (78.4%-84.0%). CONCLUSION: Internal fixation of CTB fractures can be successfully performed using either technique for imaging guidance. CT and fluoroscopy did not result in faster or more accurate screw placement compared to radiographs alone, except in determining screw length. CLINICAL SIGNIFICANCE: Mild adjustments in fluoroscopic or radiographic angle appeared to be a point of variability in the perception of screw placement. While CT is recommended for improved understanding of fracture configuration and surgical planning, radiographic guidance may be a suitable alternative for internal fixation of dorsomedial-plantarolateral fractures.

Fluoroscopically measured bronchial collapse in healthy dogs during cough exceeds 25%, and a cutoff of 60% bronchial collapse can be used to distinguish healthy from chronically coughing dogs.

Bronchomalacia, the weakening of bronchial cartilage, is a common cause of cough in dogs. The gold standard for diagnosis of bronchomalacia is bronchoscopy; however, fluoroscopy is often used as a preliminary diagnostic test due to its noninvasiveness. The normal amount of bronchial collapse in healthy dogs using fluoroscopy has not been previously established, with some authors citing <25%. The aims of this prospective and retrospective analytical observational study were to determine the normal amount of airway collapse in healthy animals, the amount of airway collapse in dogs with chronic cough and presumed bronchomalacia, and cut-off values of airway collapse during expiration and cough to distinguish between the two groups. Thoracic fluoroscopy was performed in right and left lateral recumbency during inspiration, expiration, and cough to evaluate the percentage collapse of the trachea and lobar bronchi in 45 healthy and 76 chronically coughing dogs. The bronchi of chronically coughing dogs exhibited a significantly greater amount of collapse during both expiration and cough compared with healthy dogs. Chronically coughing dogs exhibited up to 31.7 ± 26.6% collapse in expiration and 87.5 ± 23.7% collapse during cough, whereas healthy dogs exhibited 14.9 ± 6.1% collapse in expiration and 35.0 ± 13.7% collapse during cough. Based on ROC curves, the authors suggest using cut-off values of 30% during expiration and 60% during cough to distinguish between healthy dogs and those with presumed bronchomalacia. Findings suggest that though healthy dogs can exhibit a greater degree of airway collapse than previously thought, fluoroscopy can be used to distinguish between healthy and presumed bronchomalacic dogs.

Ultrasound- and fluoroscopy-guided percutaneous transhepatic shunt attenuation using a vascular plug in a complex canine intrahepatic portosystemic shunt.

A 5-month-old Pembroke Welsh corgi dog was presented with a 3-month history of lethargy, inappetence, polyuria/polydipsia, and neurological signs. A diagnosis of a complex multiple intrahepatic portosystemic shunt (IHPSS) configuration was obtained by computed tomography angiogram, abdominal ultrasonography, and perioperative fluoroscopic angiography. The IHPSS was successfully attenuated by shunt embolization with a vascular plug, using a direct percutaneous hepatic approach under ultrasonographic and fluoroscopic guidance. Long-term (4 y) follow-up revealed resolution of all clinical signs. The owner elected to continue dietary modification and lactulose treatment indefinitely and the outcome was considered good. Key clinical message: Direct percutaneous hepatic approach could be considered for IHPSS attenuation in select cases where traditional transvenous approach access is considered challenging.

Atténuation percutanée trans-hépatique guidée par échographie et fluoroscopie d'un shunt porto-systémique intrahépatique canin complexe à l'aide d'un bouchon vasculaireUn chien Pembroke Welsh corgi âgé de 5 mois a été présenté avec des antécédents de léthargie, d'inappétence, de polyurie/polydipsie et de signes neurologiques depuis 3 mois. Un diagnostic de configuration complexe de shunt porto-systémique intrahépatique multiple (IHPSS) a été obtenu par angiographie par tomodensitométrie, échographie abdominale et angiographie fluoroscopique périopératoire. L'IHPSS a été atténué avec succès par embolisation du shunt avec un bouchon vasculaire, en utilisant une approche hépatique percutanée directe sous guidage échographique et fluoroscopique. Un suivi à long terme (4 ans) a révélé une résolution de tous les signes cliniques. Le propriétaire a choisi de poursuivre indéfiniment la modification du régime alimentaire et le traitement au lactulose et le résultat a été considéré comme bon.Message clinique clé :Une approche hépatique percutanée directe pourrait être envisagée pour l'atténuation de l'IHPSS dans certains cas où l'accès par voie trans-veineuse traditionnelle est considéré comme difficile.(Traduit par Dr Serge Messier).

The effect of an aiming device on the accuracy of humeral transcondylar screw placement.

OBJECTIVES: (1) To evaluate the accuracy of an aiming device on placement of humeral transcondylar screws compared to fluoroscopic methods. (2) To compare experience level on outcome. STUDY DESIGN: Randomized, match pair, prospective ex-vivo study. SAMPLE POPULATION: A total of 68 dogs. METHODS: Canine cadaveric forelimbs were randomly assigned to either aiming device or fluoroscopic-guided groups, and to diplomate or resident. Digital radiography was used to evaluate screw trajectory deviation and eccentricity on the humeral condyle. Procedure time, outcome based on experience, and complications were recorded. RESULTS: The aiming device screw trajectory angle was decreased in the right limb (1.9 ± 1.1°) compared with the left (3.6 ± 1.1°, p = .0178), and compared to fluoroscopy (3.4 ± 1.1° p = .0128). There was no difference between leg laterality with fluoroscopy (p = .9979). Trajectory angle was increased with resident versus diplomate (3.4 ± 1.1° and 2.5 ± 1.1° respectively, p = .0366). Eccentricity deviation was decreased using fluoroscopy versus aiming device (3.1 ± 0.36 mm, 4.2 ± 0.36 mm, respectively, p = .0017). The risk of joint involvement was 8 times greater in aiming device groups, though not significant (p = .0575). Significant complications included increased drill attempts in fluoroscopic groups (p = .0237). CONCLUSION: The aiming device provided accurate placement of transcondylar screws, in terms of both position on the condyle and trajectory angle. Results were similar to fluoroscopic-guided method. CLINICAL SIGNIFICANCE: An aiming device is an acceptable means of placing humeral transcondylar screws. The use of the aiming device had an eight times increased risk of joint involvement compared to fluoroscopy.

Closed reduction and fluoroscopic-guided percutaneous pinning of femoral capital physeal or neck fractures: Thirteen fractures in 11 dogs.

OBJECTIVES: To report the short-term clinical outcome and complications in dogs that underwent surgical repair of femoral capital physeal or neck fractures via fluoroscopic-guided percutaneous pinning (FGPP). STUDY DESIGN: Retrospective case series. ANIMALS: Client owned dogs (n = 11) with femoral capital physeal or neck fractures (n = 13). METHODS: Records (July 2018-July 2021) of dogs that underwent surgery for femoral capital physeal or neck fracture repair with FGPP from two hospitals were reviewed. Data collected included signalment, age, weight, preoperative lameness severity, fracture factors (etiology, Salter-Harris classification, time from injury to surgery, radiographic displacement), surgical factors (surgery time, number/size of implants, reduction quality) and outcome (follow-up examination findings, radiographic findings, complications). RESULTS: Most fractures (11/13) occurred secondary to trauma. The median time from injury to surgery was 5.5 days. There was mild radiographic displacement preoperatively in 10/13 fractures. Satisfactory fracture healing and limb function was achieved in 10/13 femurs. Complications occurred in 5/11 cases and included intra-articular implants, implant failure/nonunion, implant migration (2), and malunion. Of these five complications, two resolved with implant removal, and a salvage procedure was recommended in the remaining cases. Of the three cases requiring salvage procedures, two originally presented with radiographic evidence of fracture chronicity. CONCLUSIONS: FGPP can be used to successfully treat femoral head and neck fractures with appropriate case selection and precise surgical technique.

Fluoroscopy-Guided Surgical Removal of a Microchip from the Spinal Canal of Two Cats.

Two cats were presented with acute left-sided paresis after implantation of a microchip at the referring veterinary clinic. Neurological examinations were consistent with left-sided lesions between spinal cord segments C1 and C5. Orthogonal radiographs of the cervical spine showed a microchip dorsoventrally oriented, partially embedded in the cervical vertebral canal. Fluoroscopy was used to localize and retrieve the foreign body from the cervical spinal cord in each case. Improvement in clinical condition and return to ambulation was observed in both cats within 48 hr of surgical removal of the implant. No significant perioperative adverse events were noted during the surgical retrieval of the microchip. Two previously reported cases of intraspinal canal microchip placement had been treated surgically by hemilaminectomy. This approach carries a risk of complications, including hemorrhage from the venous sinus, iatrogenic damage to the spinal cord, and improper identification of the surgical site, requires advanced surgical training, and typically has an extended surgical time. The use of fluoroscopy to assist intraoperative localization of a spinal canal foreign body may lessen the requirement for more invasive surgical procedures.

Cholangiopancreatography in cats: a post-mortem comparison of MRI with fluoroscopy, corrosion casting and histopathology.

In human medicine, magnetic resonance cholangiopancreatography (MRCP) is a valuable diagnostic tool for hepatobiliary and pancreatic diseases. In veterinary medicine, however, data evaluating the diagnostic value of MRCP are limited. The primary objectives of this prospective, observational, analytical investigation were to assess whether MRCP reliably visualizes the biliary tract and pancreatic ducts in cats without and with related disorders, and whether MRCP images and measurements of the ducts agree with those of fluoroscopic retrograde cholangiopancreatography (FRCP), corrosion casting and histopathology. A secondary objective was to provide MRCP reference diameters for bile ducts, GB, and pancreatic ducts. Donated bodies of 12 euthanized adult cats underwent MRCP, FRCP, and autopsy with corrosion casting of the biliary tract and pancreatic ducts using vinyl polysiloxane. Diameters of the biliary ducts, gallbladder (GB), and pancreatic ducts were measured using MRCP, FRCP, corrosion casts and histopathologic slides. There was an agreement between MRCP and FRCP in measuring diameters of the GB body, GB neck, cystic duct, and common bile duct (CBD) at papilla. Strong positive correlations existed between MRCP and corrosion casting for measuring GB body and neck, cystic duct, and CBD at the extrahepatic ducts' junction. In contrast to the reference methods, post-mortem MRCP did not visualize right and left extrahepatic ducts, and pancreatic ducts in most cats. Based on this study, MRCP with 1.5 Tesla can be regarded as a contributory method to improve the assessment of feline biliary tract and pancreatic ducts when their diameter is >1 mm.

Evaluation of a Fluoroscopic Angiography Protocol in Hispaniolan Amazon Parrots (Amazona ventralis).

Fluoroscopic angiography evaluates the heart and vascular tree in real time and can be recorded for further diagnostic analysis and measurements. Although reports have been published of the use of fluoroscopic angiography in birds, this technique has not been evaluated in any avian species. The purpose of this study was to evaluate a fluoroscopic angiography protocol in 12 adult Hispaniolan Amazon parrots (Amazona ventralis). Under general anesthesia, the birds were positioned in right lateral (LAT) recumbency on a fluoroscopy table. A bolus of nonionic iodinated contrast agent was injected through a catheter inserted into the basilic or medial metatarsal vein during video acquisition. The same bolus was repeated to obtain the ventrodorsal (VD) view with the bird placed in dorsal recumbency. Eleven studies were performed. A total of 19 (10 VD, 9 LAT) continuous, real-time, fluoroscopic angiograms were successfully captured. The brachiocephalic trunk, aorta, pulmonary arteries, pulmonary veins, and caudal vena cava were visualized, and selected intraluminal measurements collected. The intraobserver and interobserver variability for 3 observers was calculated. Intraobserver agreement was found to be near perfect (intraclass correlation coefficient ≥0.95), whereas interobserver agreement was moderate to substantial (intraclass correlation coefficient ≥0.52). Coefficients of variation were excellent (VD 0.99, LAT 0.99) for intraobserver assessments and moderate (VD 0.72, LAT 0.52) for interobserver assessments. For the interobserver assessments, the VD projection measurements performed better than the LAT measurements. These results suggest that although there was some variation between different observers, relatively consistent vascular measurements could be obtained. The described fluoroscopic angiography protocol is a repeatable and reliable technique that could be useful for the diagnosis and monitoring of cardiovascular diseases in birds.

Cyclic tensile tests of Shetland pony superficial digital flexor tendons (SDFTs) with an optimized cryo-clamp combined with biplanar high-speed fluoroscopy.

BACKGROUND: Long-term cyclic tensile testing with equine palmar/plantar tendons have not yet been performed due to problems in fixing equine tendons securely and loading them cyclically. It is well established that the biomechanical response of tendons varies during cyclic loading over time. The aim of this study was to develop a clamping device that enables repetitive cyclic tensile testing of equine superficial digital flexor tendon for at least 60 loading cycles and for 5 min. RESULTS: A novel cryo-clamp was developed and built. Healthy and collagenase-treated pony SDFTs were mounted in the custom-made cryo-clamp for the proximal tendon end and a special clamping device for the short pastern bone (os coronale). Simultaneously with tensile testing, we used a biplanar high-speed fluoroscopy system (FluoKin) to track tendon movement. The FluoKin system was additionally validated in precision measurements. During the cyclic tensile tests of the SDFTs, the average maximal force measured was 325 N and 953 N for a length variation of 2 and 4 % respectively. The resulting stress averaged 16 MPa and 48 MPa respectively, while the modulus of elasticity was 828 MPa and 1212 MPa respectively. Length variation of the metacarpal region was, on average, 4.87 % higher after incubation with collagenase. The precision of the FluoKin tracking was 0.0377 mm, defined as the standard deviation of pairwise intermarker distances embedded in rigid bodies. The systems accuracy was 0.0287 mm, which is the difference between the machined and mean measured distance. CONCLUSION: In this study, a good performing clamping technique for equine tendons under repetitive cyclic loading conditions is described. The presented cryo-clamps were tested up to 50 min duration and up to the machine maximal capacity of 10 kN. With the possibility of repetitive loading a stabilization of the time-force-curve and changes of hysteresis and creep became obvious after a dozen cycles, which underlines the necessity of repetitive cyclical testing. Furthermore, biplanar high-speed fluoroscopy seems an appropriate and highly precise measurement tool for analysis of tendon behaviour under repetitive load in equine SDFTs.

Radiation exposure associated with percutaneous fluoroscopically guided lag screw fixation for sacroiliac luxation in dogs.

OBJECTIVE: To determine radiation exposure to surgical personnel and to evaluate the accuracy of a modified percutaneous lag screw fixation technique for sacroiliac luxation (SIL) under fluoroscopic guidance in dogs. STUDY DESIGN: Cadaveric experimental study. SAMPLE POPULATION: Seventeen beagle cadavers with iatrogenic SIL. METHODS: Seventeen beagles with iatrogenic SIL underwent reduction and stabilization with 3.5-mm screws. Hypodermic needles (14 gauge) and fluoroscopy were used to orient two Kirschner wires for temporary stabilization and to guide drilling of glide and pilot holes using cannulated drill bits. Duration of surgery and radiation exposure were recorded. Postoperative computed tomographic evaluation of screw position and angulation was performed. RESULTS: Average time for fixation was 15.85 minutes (range, 6.37-33.5). Cumulative radiation doses of 0.4 mrem for the dominant arm of the assistant and 0 mrem for the primary surgeon were recorded. The mean dorsoventral and craniocaudal screw angles were 0.68° ± 3.4° (range - 5.4° to 9.5°) and 1.9° ± 3.2° (range - 4.3° to 9.1°), respectively. Sixteen of the 17 dogs had 100% sacral screw purchase, with the remaining case achieving 93.4% purchase. CONCLUSION: Fluoroscopy-assisted percutaneous placement of 3.5-mm cortical screws in lag fashion performed with 14-gauge needles in conjunction with Kirschner wires and cannulated drill bits yielded repeatable accurate screw placement with low levels of ionizing radiation exposure to the surgical team. CLINICAL SIGNIFICANCE: The described technique may be a viable method for minimally invasive osteosynthesis fixation of SIL with low levels of radiation exposure to the surgical team. These results provide evidence to support further evaluation of radiation exposure in clinical cases and can aid in study design and sample size determination.

Three-dimensional printed guides for screw placement in equine navicular bones.

OBJECTIVE: To determine the influence of a custom 3D-printed guide for placement of cortical bone screws in the equine navicular bone. STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Eight pairs of normal adult equine forelimbs. METHODS: A 3.5 × 55 mm cortical screw was placed in the longitudinal axis of each intact navicular bone. Screws were placed with a 3D-printed guide (3D) in one bone and with a traditional aiming device (AD) in the contralateral bone within each pair. Duration of surgery and the number of fluoroscopy images were compared between techniques. Screw placement was subjectively evaluated by gross examination and scored by three boarded veterinary surgeons. RESULTS: The use of a 3D-printed guide reduced the duration of surgery by 6.6 min (±1.5 min) compared to traditional screw placement (20.7 min ± 4.8 min, p < .01). Fewer peri-operative fluoroscopic images were obtained when the 3D guide was used (18 images ± 2.6 images vs. 40 images ± 5.1, p < .01). No difference was detected in navicular screw placement. CONCLUSION: The use of a 3D guide decreased the time required to place screws and the number of intraoperative images taken without affecting screw placement in intact navicular bones. CLINICAL RELEVANCE: 3D-printed guides can aid in the study, practice, and execution of surgical procedures reducing surgical time and radiation exposure throughout the operative period achieving similar results to those obtained with a conventional approach.

Videofluoroscopy, CT angiography, and ultrasonography of congenital esophageal stenosis in a Labrador retriever.

A 7-week-old Labrador retriever presented for further investigation into acute onset regurgitation, following weaning from liquid to solid food. A videofluoroscopic swallow study demonstrated a severe, focal esophageal dilation in the mid-cervical region, with marked luminal narrowing distally. Computed tomography with angiography revealed esophageal stenosis, extending from C4-T2, secondary to circumferential esophageal wall thickening. With the concern for development of secondary aspiration pneumonia, the owners elected to euthanize the dog and consented to postmortem examination. A diagnosis of segmental, cervical esophageal muscular hypertrophy was made on necropsy, consistent with the fibromuscular thickening type of congenital esophageal stenosis reported in humans.

Evaluation of a multibody kinematics optimization method for three-dimensional canine pelvic limb gait analysis.

BACKGROUND: Skin marker-based three-dimensional kinematic gait analysis were commonly used to assess the functional performance and movement biomechanics of the pelvic limb in dogs. Unfortunately, soft tissue artefact would compromise the accuracy of the reproduced pelvic limb kinematics. Multibody kinematics optimization framework was often employed to compensate the soft tissue artefact for a more accurate description of human joint kinematics, but its performance on the determination of canine pelvic limb skeletal kinematics has never been evaluated. This study aimed to evaluate a multibody kinematics optimization framework used for the determination of canine pelvic limb kinematics during gait by comparing its results to those obtained using computed tomography model-based fluoroscopy analysis. RESULTS: Eight clinically normal dogs were enrolled in the study. Fluoroscopy videos of the stifle joint and skin marker trajectories were acquired when the dogs walked on a treadmill. The pelvic limb kinematics were reconstructed through marker-based multibody kinematics optimization and single-body optimization. The reference kinematics data were derived via a model-based fluoroscopy analysis. The use of multibody kinematics optimization yielded a significantly more accurate estimation of flexion/extension of the hip and stifle joints than the use of single-body optimization. The accuracy of the joint model parameters and the weightings to individual markers both influenced the soft tissue artefact compensation capability. CONCLUSIONS: Multibody kinematics optimization designated for soft tissue artefact compensation was established and evaluated for its performance on canine gait analysis, which provided a further step in more accurately describing sagittal plane kinematics of the hip and stifle joints.

Femorotibial kinematics in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament insufficiency: An in vivo fluoroscopic analysis during walking.

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.

Evaluation of microwave ablation for local treatment of dogs with distal radial osteosarcoma: A pilot study.

OBJECTIVE: To evaluate the feasibility and safety of microwave ablation (MWA) as a modality to induce tumor necrosis within distal radial osteosarcoma (OSA). STUDY DESIGN: Pilot study. ANIMALS: Six client-owned dogs with distal radius OSA confirmed by cytological examination. METHODS: Dogs underwent computed tomography for surgical planning before general anesthesia for fluoroscopy-guided ablation. Computed tomography was repeated 48 hours after MWA, before amputation. The ablated tumor was evaluated with histopathology. RESULTS: Six dogs underwent MWA of distal radius OSA. A lower power setting (30 W) was selected for the first two dogs to avoid collateral soft tissue damage. The power was increased to 75 W for the last four dogs. The temperature was maintained between 45°C and 55°C (113 °F-131 °F) at the bone/soft tissue interface. Tumor necrosis varied between 30% and 90% (median, 55%) according to histopathology. No intraoperative or periprocedural complications were observed. CONCLUSION: Microwave ablation induced variable tumor necrosis and did not induce immediate postablation complications in these six dogs with distal radius OSA. CLINICAL SIGNIFICANCE: These results justify further evaluation of MWA as a potential modality to treat primary bone lesions in dogs.

Fluoroscopy-guided approach to the lumbar dorsal root ganglion in dogs: cadaver study in Beagles.

OBJECTIVE: To evaluate an approach to the canine lumbar dorsal root ganglion (DRG), a significant contributor to the pain pathway, using new methylene blue staining. STUDY DESIGN: Prospective randomized study. ANIMALS: A total of three Beagle dog cadavers weighing 10.4 ± 0.7 kg (mean ± standard deviation). METHODS: Bilateral third to fifth lumbar DRG approaches were performed in three dog cadavers positioned in sternal recumbency. The mammillary process was palpated, and a 22 gauge spinal needle was inserted through the skin 1 cm lateral to the process and directed towards the median plane at a 45° angle to the dorsal plane. The needle was advanced along the transverse plane until touching bone, or a popping sensation was detected. Under fluoroscopic guidance, the position of the needle tip was adjusted to be in the cranioventral part of the intervertebral foramen. The location of the needle was confirmed by demarcation of the nerve roots after iohexol (0.1 mL) injection. For evaluation of the DRG approach, new methylene blue (0.1 mL) was injected. Subsequently, anatomical dissection of the area was performed. The DRG staining was scored as follows: 0, no staining; 1, partial (<50%); 2, partial (≥50%); and 3, complete staining. Comparisons among the staining scores of the third to fifth DRG were assessed with the Friedman test. RESULTS: Staining score 3 was achieved in 14 of 18 (77.8%) sites. Staining scores 2, 1 and 0 were identified at two, one and one of the 18 sites, respectively. No significant difference was noted in the staining scores among the third to fifth DRGs (p = 0.78). CONCLUSIONS AND CLINICAL RELEVANCE: The technique used for DRG injections achieved adequate DRG staining, supporting use of the fluoroscopy-guided approach to the canine lumbar DRG.

Diaphragmatic dysfunction in dogs with cervical spinal disorders before and after surgery using fluoroscopy, motion-mode ultrasound and radiography was not different than a group of control dogs.

Cervical spinal disorders can lead to life-threatening respiratory complications. Diaphragmatic dysfunction is attributed to spinal cord morbidity secondary to cervical myelopathy or decompressive surgical intervention. The purpose of this observational case-control study was to determine the frequency of diaphragmatic dysfunction in dogs with cervical spinal disorders and a control group, the strength of association between cervical myelopathies and decompressive surgery with diaphragm paresis, and the agreement between and clinical usefulness of fluoroscopy, motion-mode ultrasonography, and radiography for diagnosing diaphragmatic dysfunction. Thirty-five client-owned dogs were recruited with 14 control dogs and 21 test dogs. Dogs were evaluated for the presence of diaphragmatic dysfunction using radiography, M-mode ultrasonography, and fluoroscopy before and after an anesthetic or surgical event. Diaphragmatic dysfunction was observed more frequently in dogs with cervical spinal disease prior to surgery (8/21; 38.1%) compared to control dogs (3/14; 21.4%) but was not statistically significant (P = .30). The occurrence of diaphragmatic dysfunction did not significantly increase following surgical decompression in either group. There was no to slight agreement between all imaging modalities. Most dogs with diaphragmatic dysfunction were asymptomatic. Diaphragmatic dysfunction was not statistically associated with cervical myelopathy or decompressive surgery. Ultrasonography and radiography were not useful diagnostic tests for determining diaphragmatic dysfunction in asymptomatic dogs when compared to fluoroscopy.