External skeletal fixation for the treatment of pelvic fractures in cats.

OBJECTIVE: To report the technique and the outcome for the repair of pelvic fractures in cats using external skeletal fixation (ESF). STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned cats (n = 125). METHODS: Medical records of cats with pelvic fractures, treated with an ESF between June 2001 and June 2009, were reviewed. Preoperative, immediate postoperative, and more than 4 weeks' postoperative radiographs were compared. Clinical examination was performed 4 to 9 weeks following surgery. Longer term follow up (4 to 80 months) was conducted by client questionnaire. RESULTS: No intraoperative complications occurred. There was no change in the pelvic canal width observed on follow-up radiographs (p = .16). Implant loosening was noted on follow-up radiographs in 16/125 (13%) of cases, and 67/803 (8%) pins were palpably loose at the time of frame removal. The mean time to frame removal was 37 ± 9 days. No long-term complications were reported. Long-term mean mobility score was 95 ± 5 and median lameness was 0 (range: 0-2). CONCLUSION: An ESF may be successfully applied for the stabilization of various pelvic fractures in cats. CLINICAL SIGNIFICANCE: The application of an ESF for the management of pelvic fractures in cats provides good outcomes.

Streamlining atrial fibrillation ablation management using a digitization solution.

Aims: Catheter ablation is a widely accepted intervention for atrial fibrillation (AF) management. Prior to undertaking this procedure, thorough patient education on its efficacy and potential complications is crucial. Additionally, educating patients about stroke risk management and anticoagulant therapy is imperative. At Mater Private Hospital in Dublin, we implemented a solution, integrating a customized treatment pathway and a mobile application. This patient-centred approach aims to optimize the clinical management of AF catheter ablation candidates, focusing on knowledge gaps and adherence to guideline-based care to enhance overall outcomes. Methods and results: The application automates pre-operative assessments and post-operative support, facilitating seamless patient-clinician communication. During the observation period (September 2022-April 2023), 63 patients installed the app. Patient adherence to the pathway was strong, with 98% of patients actively engaging in the treatment pathway and with 81% completing all pre-operative tasks. The average enrolment-to-admission duration was 14 days, and post-ablation tasks were fulfilled by 62% of patients within an average of 36 days. Operators perceived the solution as user-friendly and effective in enhancing patient connectivity. Patient satisfaction was high, and knowledge about AF improved notably through the solution, particularly concerning the recognition of symptoms and anticoagulation therapy-related complications. Conclusion: Our findings demonstrate the successful implementation of the app-based Ablation Solution, showcasing widespread patient use, improved adherence, and enhanced understanding of AF and its treatments. The system effectively connects healthcare providers with patients, offering a promising approach to streamline AF catheter ablation management and improve patient outcomes.

Predictors of the need for atrioventricular nodal ablation following redo ablation for atrial fibrillation.

Background: Patients who have recurrent atrial fibrillation (AF) following redo catheter ablation may eventually be managed with a pace-and-ablate approach, involving pacemaker implant followed by atrioventricular nodal ablation (AVNA). We sought to determine which factors would predict subsequent AVNA in patients undergoing redo AF ablation. Methods: We analyzed patients undergoing redo AF ablations between 2013 and 2019 at our institution. Follow-up was censored on December 31, 2021. Patients with no available follow-up data were excluded. Time-to-event analysis with Cox proportional hazard regression was used to compare those who underwent AVNA to those who did not. Results: A total of 467 patients were included, of whom 39 (8.4%) underwent AVNA. After multivariable adjustment, female sex (aHR 4.68 [95% CI 2.30-9.50]; p < 0.001), ischemic heart disease (aHR 2.99 [95% CI 1.25-7.16]; p = 0.014), presence of a preexisting pacemaker (aHR 3.25 [95% CI 1.10-9.60]; p = 0.033), and persistent AF (aHR 2.22 [95% CI 1.07-4.59]; p = 0.032) were associated with increased risk of subsequent AVNA requirement. Conclusion: Female sex, ischemic heart disease, and persistent AF may be useful clinical predictors of the requirement for subsequent AVNA and may be considered as part of shared clinical decision making.

Refractory Inappropriate Sinus Tachycardia Treated with Pulsed-field Ablation of the Sinus Node: A Breath of Fresh Air.

The pathogenesis of inappropriate sinus tachycardia is not well understood, and the symptoms of inappropriate sinus tachycardia can be difficult to manage. Here, we present a case of inappropriate sinus tachycardia refractory to medical therapy and discuss our approach to sinus node modification by catheter ablation.

Silent pulmonary veins at redo ablation for atrial fibrillation: Implications and approaches.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Despite promising success rates, redo ablation is sometimes required. At redo, PVs may be found to be isolated (silent) or reconnected. We studied patients with silent vs reconnected PVs at redo and analysed associations with adverse outcomes. METHODS: Patients undergoing redo AF ablations between 2013 and 2019 at our institution were included and stratified into silent PVs or reconnected PVs. The primary outcome was a composite of further redo ablation, non-AF ablation, atrioventricular nodal ablation, and death. Secondary outcomes included arrhythmia recurrence. RESULTS: A total of 467 patients were included with mean 4.6 ± 1.7 years follow-up, of whom 48 (10.3%) had silent PVs. The silent PV group had had more often undergone >1 prior ablation (45.8% vs 9.8%; p<0.001), had more persistent AF (62.5% vs 41.1%; p=0.005) and had more non-PV ablation performed both at prior ablation procedures and at the analysed redo ablation. The primary outcome occurred more frequently in those with silent PVs (25% vs 13.8%; p=0.053). Arrhythmia recurrence was also more common in the silent PV group (66.7% vs 50.6%; p=0.047). After multivariable adjustment, female sex (aHR 2.35 [95% CI 2.35-3.96]; p=0.001) and ischaemic heart disease (aHR 3.21 [95% CI 1.56-6.62]; p=0.002) were independently associated with the primary outcome, and left atrial enlargement (aHR 1.58 [95% CI 1.20-2.08]; p=0.001) and >1 prior ablation (aHR 1.88 [95% CI 1.30-2.72]; p<0.001) were independently associated with arrhythmia recurrence. Whilst a finding of silent PVs was not itself significant after multivariable adjustment, this provides an easily assessable parameter at clinically indicated redo ablation which informs the clinician of the likelihood of a worse future prognosis. CONCLUSIONS: Patients with silent PVs at redo AF ablation have worse clinical outcomes.

Picking the Locked Door: Experiences and Techniques in Transseptal Puncture Post-Atrial Septal Defect Occlusion.

The management of atrial septal defects (ASDs) has been revolutionized by the advent of percutaneous transvenous occlusion devices. This case series describes techniques required to perform a transeptal puncture safely and effectively in patients postimplantation of an atrial septal defect occluder to facilitate catheter ablation of atrial arrhythmias. (Level of Difficulty: Intermediate.).

The impact of steerable sheath visualization during catheter ablation for atrial fibrillation.

AIMS: Incorporating a steerable sheath that can be visualized using an electroanatomical mapping (EAM) system may allow for more efficient mapping and catheter placement, while reducing radiation exposure, during ablation procedures for atrial fibrillation (AF). This study evaluated fluoroscopy usage and procedure times when a visualizable steerable sheath was used compared with a non-visualizable steerable sheath for catheter ablation for AF. METHODS AND RESULTS: In this retrospective, observational, single-centre study, patients underwent catheter ablation for AF using a steerable sheath that is visualizable using the CARTO EAM (VIZIGO; n = 57) or a non-visualizable steerable sheath (n = 34). The acute procedural success rate was 100%, with no acute complications in either group. Use of the visualizable sheath vs. the non-visualizable sheath was associated with a significantly shorter fluoroscopy time [median (first quartile, third quartile), 3.4 (2.1, 5.4) vs. 5.8 (3.8, 8.6) min; P = 0.003], significantly lower fluoroscopy dose [10.0 (5.0, 20.0) vs. 18.5 (12.3, 34.0) mGy; P = 0.015], and significantly lower dose area product [93.0 (48.0, 197.9) vs. 182.2 (124.5, 355.0) µGy·m2; P = 0.017] but with a significantly longer mapping time [12.0 (9.0, 15.0) vs. 9.0 (7.0, 11.0) min; P = 0.004]. There was no significant difference between the visualizable and non-visualizable sheaths in skin-to-skin time [72.0 (60.0, 82.0) vs. 72.0 (55.5, 80.8) min; P = 0.623]. CONCLUSION: In this retrospective study, use of a visualizable steerable sheath for catheter ablation of AF significantly reduced radiation exposure vs. a non-visualizable steerable sheath. Although mapping time was longer with the visualizable sheath, the overall procedure time was not increased.

Limb-Sparing Surgery in Two Cats Using a Femoral Endoprosthesis with an Integrated Total Knee Replacement Implant.

OBJECTIVE: The aim of this study was to describe a novel limb-sparing technique for the management of feline bone neoplasia using a custom-made femoral endoprosthesis in combination with a total knee replacement (TKR) prosthesis. METHODS: Two cats with distal femoral bone tumours underwent pelvic limb salvage procedures with custom-made implants designed from patient-specific computed tomography images to replace the distal femur and the stifle. In case 1, the first-generation implant was a combination of a cemented femoral endoprosthesis with a uniaxial hinged cemented TKR prosthesis. Due to aseptic loosening of the endoprosthesis, revision was performed with a second-generation femoral endoprosthesis modified with a short intramedullary peg and a lateral bone plate for immediate stability. In case 2, a third-generation endoprosthesis with an intramedullary peg and two orthogonal bone plates for immediate stability, combined with a custom-designed rotationally hinged cemented TKR prosthesis, was used. Clinical and radiographic follow-up was recorded. RESULTS: After revision surgery in case 1 and with the third-generation implant in case 2, no complications were encountered. Both cats showed minor mechanical restriction of stifle range of motion and good clinical long-term outcome without local tumour recurrence. CONCLUSION: The combination of a femoral endoprosthesis and a TKR prosthesis can be a viable alternative for distal femoral limb salvage in cats.

Clinical Cohort Study in Canine Patients, to Determine the Average Platelet and White Blood Cell Number and Its Correlation with Patient's Age, Weight, Breed and Gender: 92 Cases (2019-2020).

Due to its easy preparation and that it is well tolerated, the use of autologous platelet-rich plasma (PRP) has become increasingly popular in regenerative medicine. However, there are still no clear guidelines on how it should be classified or whether the individual canine patient's clinical status can influence its quality. OBJECTIVE: This study aims to show if the weight, age, sex, neutered status or breed of canine patients have any correlation with the composition of PRP. DESIGN: A blinded count of the platelets and white blood cells (WBC) was performed from 111 samples from 92 client owned dogs undergoing treatment for degenerative joint disease (DJD). The results were analysed using Pearson correlation test, ANOVA test or Student T-test. RESULTS: There is a positive correlation between the number of platelets and WBC in canine patients of different breeds, but there was no significant difference on the platelet number and WBC number among the different breeds. The weight of the patient is also directly correlated to the platelet number (p = 0.003) but not WBC number. WBC number was negatively correlated to the weight of the patient. The sex and age of the patient did not affect platelets and WBC number, although WBC number is increased in non-neutered male population (p = 0.003). However, it would be interesting to investigate whether the growth factors released from the platelet granules are affected by patient variables in a canine population. CONCLUSIONS: Our results show that it is possible to obtain good quality autologous PRP, irrespective of age, sex, neutered status or weight of the patient, for PRP regenerative therapy.

Clinical outcomes following intra-articular injection of autologous adipose-derived mesenchymal stem cells for the treatment of osteoarthritis in dogs characterized by weight-bearing asymmetry.

AIMS: This study investigates the effects of intra-articular injection of adipose-derived mesenchymal stem cells (AdMSCs) and platelet-rich plasma (PRP) on lameness, pain, and quality of life in osteoarthritic canine patients. METHODS: With informed owner consent, adipose tissue collected from adult dogs diagnosed with degenerative joint disease was enzymatically digested and cultured to passage 1. A small portion of cells (n = 4) surplus to clinical need were characterized using flow cytometry and tri-lineage differentiation. The impact and degree of osteoarthritis (OA) was assessed using the Liverpool Osteoarthritis in Dogs (LOAD) score, Modified Canine Osteoarthritis Staging Tool (mCOAST), kinetic gait analysis, and diagnostic imaging. Overall, 28 joints (25 dogs) were injected with autologous AdMSCs and PRP. The patients were followed up at two, four, eight, 12, and 24 weeks. Data were analyzed using two related-samples Wilcoxon signed-rank or Mann-Whitney U tests with statistical significance set at p < 0.05. RESULTS: AdMSCs demonstrated stem cell-like characteristics. LOAD scores were significantly lower at week 4 compared with preinjection (p = 0.021). The mCOAST improved significantly after three months (p = 0.001) and six months (p = 0.001). Asymmmetry indices decreased from four weeks post-injection and remained significantly lower at six months (p = 0.025). CONCLUSION: These improvements in quality of life, reduction in pain on examination, and improved symmetry in dogs injected with AdMSCs and PRP support the effectiveness of this combined treatment for symptom modification in canine OA for six months. Cite this article: Bone Joint Res 2021;10(10):650-658.

Custom-built constrained uniaxial and rotating hinge total knee replacement in cats: Clinical application, design principles, surgical technique, and clinical outcome.

OBJECTIVE: To describe the design principles and evolution, surgical technique, and outcome for custom constrained (uniaxial and rotating hinge) total knee replacement (TKR) in cats. STUDY DESIGN: Retrospective case series. ANIMALS: Nine cats with traumatic stifle luxation (n = 8) or severe distal femoral deformity (n = 1) were considered suitable candidates. METHODS: Cats that met eligibility criteria and received a custom TKR between 2009 and 2018 by a single surgeon were included in this case series. Three generations of implant were used. Implant positioning was assessed by postoperative orthogonal radiography. Functional outcome was determined by clinical assessment, owner interview, and a feline musculoskeletal pain index questionnaire. RESULTS: Median clinical follow-up time was 12 months (range, 4-41); follow-up time was increased to 29 months (range, 22-47) when results of functional questionnaires with owner were included. Median radiographic follow-up was 12 months (range, 4-25). One cat had a catastrophic outcome. Three cats had good outcomes, and five cats had excellent outcomes. CONCLUSION: Most cats treated with custom-built TKR achieved good to excellent outcomes. CLINICAL SIGNIFICANCE: Custom TKR is a viable option for the treatment of severe pathologies of the feline stifle. Additional research is required to fully evaluate implant suitability.

Kinematics of a Novel Canine Cervical Fusion System.

OBJECTIVE: The aim of this study was to determine the biomechanical behaviour of a novel distraction-fusion system, consisting of an intervertebral distraction screw, pedicle locking screws and connecting rods, in the canine caudal cervical spine. STUDY DESIGN: Biomechanical study in cadaveric canine cervicothoracic (C3-T3) spines (n = 6). Cadaveric spines were harvested, stripped of musculature, mounted on a four-point bending jig, and tested using non-destructive four-point bending loads in extension (0-100 N), flexion (0-60 N) and lateral bending (0-40 N). Angular displacement was recorded from reflective optical trackers rigidly secured to C5, C6 and C7. Data for primary and coupled motions were collected from intact spines and following surgical stabilization (after ventral annulotomy and nucleotomy) with the new implant system. RESULTS: As compared with the intact spine, instrumentation significantly reduced motion at the operated level (C5-C6) with a concomitant non-significant increase at the adjacent level (C6-C7). CONCLUSION: The combination of a locking pedicle screw-rod system and intervertebral spacer provides an alternative solution for surgical distraction-stabilization in the canine caudal cervical spine and supports the feasibility of using this new implant system in the management of disc-associated cervical spondylomyelopathy in dogs. The increase in motion at C6-C7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this.

Comparison of Fat Harvested from Flank and Falciform Regions for Stem Cell Therapy in Dogs.

BACKGROUND: Adipose tissue has recently gained attention as a source of mesenchymal stem cells (AdMSCs) for applications in treating degenerative joint disease in veterinary patients. This study aimed to quantify the stromal vascular fractions (SVFs) and colony forming units (CFU) of AdMSCs from the falciform and flank regions and compare dogs of different ages and weights. METHODS: Fat tissue was harvested from the flank (21 dogs) and falciform regions (17 dogs). The fat tissue was enzymatically digested and the number of nucleated cells in the SVF was counted. The SVF was cultured in vitro and the cell growth was assessed by counting the CFU per gram of fat and the aspect ratio of the cells. CONCLUSIONS: There was no significant difference in the number of nucleated cells in the SVF from the two sites. The CFU/g of fat from falciform was 378.9 ± 293 g and from flank was 486.8 ± 517 g, and this was also insignificant. Neither age nor weight of the patient had an impact on the SVF or CFU/g. No surgical complications were reported from either of the sites. Harvesting fat for stem cell therapy for intra-articular therapy of degenerative joint disease can be an easy and fast process when obtaining the fat either from the flank or the falciform region, and it is not age or weight dependent. The harvest site for clinical canine patients can be left to the surgeon's discretion and comfort.

Correction of pes varus deformity in a Miniature Dachshund by true spherical osteotomy with a dome saw blade.

CASE DESCRIPTION: A 6-month-old male Miniature Dachshund was referred for examination and correction of a unilateral pes varus deformity. CLINICAL FINDINGS: Clinical examination and diagnostic imaging revealed varus, procurvatum, and internal torsion of the distal aspect of the left tibia causing intermittent lameness. TREATMENT AND OUTCOME: True spherical osteotomy performed with a dome-shaped saw allowed correction of the deformity in 3-D, and orthogonal internal plate fixation provided stabilization. No intraoperative or immediate postoperative complications developed. Outcome as judged by the clinician and the owners was satisfactory 2 weeks after surgery and excellent at each subsequent assessment. The patient remained free of clinical signs at the last follow-up 30 months after surgery. CLINICAL RELEVANCE: To the authors' knowledge, this case represented the first time a true spherical osteotomy was used to correct a pes varus deformity in a canine patient.

Treatment of a large osseous defect in a feline tarsus using a stem cell-seeded custom implant.

The aim of this study is to describe the treatment of an infected segmental bone defect in a cat using a novel, custom-designed titanium implant seeded with adipose-derived stem cells (AdMSCs) to facilitate osseous ingrowth and preserve limb function. Large bone defects occur secondary to trauma, infection, or neoplasia and often result in amputation. We established a novel autologous AdMSC-impregnated trabecular metal spacer made using 3D printing, to bridge the distal tibia and metatarsal bones in the left pelvic limb of a cat that had previously undergone right pelvic limb amputation. Six months postoperatively, there was radiographic evidence of bone growth and implant integration. A titanium spacer seeded with AdMSCs successfully encouraged bone ingrowth in a large defect site and successfully preserved limb function. However, further studies are needed to justify the use of differentiated stem cell impregnated mesh as a framework to bridge large bone defects.

Guidelines for the Execution of True Spherical Osteotomies Using a Modified Dome Blade Design.

OBJECTIVES: The purpose of this study was to explore the trigonometric principles of the spherical osteotomy, establish guidelines for its application and test the guidelines on bone models using a new blade design. We propose a new rule of osteotomies incorporating the outlined geometric principles, and applicable to the use of spherical cuts in veterinary orthopaedic surgery. MATERIALS AND METHODS: The trigonometric principles for the execution of neutral, closing and opening spherical osteotomies were explored in silico. A modification of the existing commercially available dome blade was designed and manufactured such that it facilitated the performance of spherical osteotomy with a minimized blade radius. A pilot study was performed whereby the modified dome blade was used to create spherical osteotomy in canine radial bone models. The surfaces of the osteotomy models were laser-scanned using a three-dimensional (3D) scanner; the resultant scans were imported into and analysed using a commercial 3D analysis software. The accuracy of osteotomy execution was measured as the distance between the targeted centre of osteotomy and the actual centre of osteotomy as found on the 3D scans. RESULTS: By utilizing the geometric principles of spherical osteotomy, an accurate osteotomy position was achieved. The centre of the spherical cut performed on bone models was confirmed to be within 5% tolerance of the location as planned in silico demonstrating the accurate and relevant clinical application of geometric principles. CLINICAL SIGNIFICANCE: The trigonometric guidelines for the execution of spherical osteotomy can be applied in a pre-clinical environment with accuracy. The new guidelines combined with the proposed new rule for spherical osteotomy utilizing the new blade design are translatable into clinical application, permitting the surgeon to accurately plan osteotomy application while mitigating the significant loss of bone-to-bone contact during correction of torsional deformities inherent in the principles of dome osteotomy use.

Electrodiagnostic findings in dogs with apparently painful lumbosacral foraminal stenosis.

BACKGROUND: Development of management strategies for lumbosacral stenosis in dogs is hampered by the lack of objective diagnostic criteria and outcome measures. OBJECTIVE: To explore the suitability of electrodiagnostic tests as ancillary diagnostic aids, inclusion criteria, or outcome measures. SAMPLE POPULATION: Sixty-one client-owned dogs with clinical signs of lumbosacral foraminal stenosis. METHODS: A blinded, cross-sectional cohort study. Fifty-one dogs exhibiting apparent lumbosacral pain or pelvic limb lameness with no detected orthopedic cause had blinded review of magnetic resonance imaging (MRI), allowing classification as affected with foraminal stenosis (25 dogs), unaffected (20 dogs), or another diagnosis (6 dogs). The presence of electromyographic changes and tibial neurography variables were compared between groups. RESULTS: Cord dorsum potential onset latency, F-wave onset latency (both corrected for limb length), and F-ratio were increased in dogs with lumbosacral foraminal stenosis versus those without, although there was overlap of the values between groups. The proportion of dogs with electromyographic changes was not significantly greater in MRI-affected dogs. CONCLUSION: Electrophysiological testing is a useful ancillary test, either to provide stricter inclusion criteria and outcome measures or to aid clinical decision-making in equivocal cases.