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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.

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.

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.

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.

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.

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.

Background Occipitoatlantoaxial malformation (OAAM) is reported rarely in dogs and few treatment options are described. The congenital condition is thought to be associated with a proatlas re-segmentation failure resulting in malformation and malalignment of the craniovertebral junction which can result in C1 to 5 myelopathic signs. Methods Customized three-dimensional printed locking plate with trajectory screw implantation points for the stabilization of the atlantoaxial joint in a dog with OAAM. The dog was evaluated at time points 0, 2, 6 and 9 months to determine clinical outcome, degree of fusion, implant positioning and subsidence. Results New bone formation was noted 9 months after surgery, but complete fusion remained absent, although no implant failure occurred. Clinically, the dog made a good recovery and was able to exercise normally 9 months after surgery. The only residual deficit was a subtle left-sided cervical torticollis. Clinical Significance This report illustrates a management option and outcome of a dog treated with OAAM. Collaboration between clinicians and engineers provides a new dimension of care for patients with vertebral malformations.

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.

Objective To report the outcome of dogs with large, caudocentral, osteochondritis dissecans (OCD) lesions of the humeral head treated with synthetic osteochondral resurfacing (SOR) implants. Study design Retrospective case series. Animals Twenty-four client-owned large breed or giant dogs. Methods The medical records of all dogs treated with first generation (G1) and second generation (G2) SOR implants were reviewed. All dogs were assessed with clinical examination and imaging 12 weeks after surgery. Assessment of outcome was based on subjective assessment of lameness, scoring of postoperative radiographs, and the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. Results Osteochondral resurfacing was performed with a G1 implant in 13 dogs (15 shoulders) and a G2 implant in 11 dogs (13 shoulders). Lameness resolved in all dogs treated with G1 implants and in 10 dogs treated with G2 implants by 12 weeks after surgery. One dog treated with a G2 implant was found to have an implant-associated infection, requiring implant removal. No recurrence of lameness was reported in 9 limbs treated with G1 implants and 10 limbs treated with G2 implants that were available for clinical review at a median time of 387 and 365 days, respectively, after surgery. Mean postoperative LOAD scores were 4.2 of 52 and 5.2 of 52 in dogs treated with a G1 or a G2 implant, respectively. Conclusion Synthetic resurfacing was technically feasible in all joints of this study and resulted in good clinical results. Clinical significance The use of SOR implants seems viable to treat large caudocentral OCD lesions of the humeral head in dogs and warrants prospective comparison with conventional arthroscopic treatment.

The roughness length values for momentum, temperature, and water vapour are key inputs to the bulk aerodynamic method for estimating turbulent heat flux. Measurements of site-specific roughness length are rare for glacier surfaces, and substantial uncertainty remains in the values and ratios commonly assumed when parameterising turbulence. Over three melt seasons, eddy covariance observations were implemented to derive the momentum and scalar roughness lengths at several locations on two mid-latitude mountain glaciers. In addition, two techniques were developed in this study for the remote estimation of momentum roughness length, utilising lidar-derived digital elevation models with a 1×1 m resolution. Seasonal mean momentum roughness length values derived from eddy covariance observations at each location ranged from 0.7 to 4.5 mm for ice surfaces and 0.5 to 2.4 mm for snow surfaces. From one season to the next, mean momentum roughness length values over ice remained relatively consistent at a given location (0–1 mm difference between seasonal mean values), while within a season, temporal variability in momentum roughness length over melting snow was found to be substantial (> an order of magnitude). The two remote techniques were able to differentiate between ice and snow cover and return momentum roughness lengths that were within 1–2 mm (≪ an order of magnitude) of the in situ eddy covariance values. Changes in wind direction affected the magnitude of the momentum roughness length due to the anisotropic nature of features on a melting glacier surface. Persistence in downslope wind direction on the glacier surfaces, however, reduced the influence of this variability. Scalar roughness length values showed considerable variation (up to 2.5 orders of magnitude) between locations and seasons and no evidence of a constant ratio with momentum roughness length or each other. Of the tested estimation methods, the Andreas (1987) surface renewal model returned scalar roughness lengths closest to those derived from eddy covariance observations. Combining this scalar method with the remote techniques developed here for estimating momentum roughness length may facilitate the distributed parameterisation of turbulent heat flux over glacier surfaces without in situ measurements.

This report describes a technique and the outcome following surgical revision of a periprosthetic infected total hip replacement (THR) in a single-stage procedure with the use of antibiotic-impregnated bioabsorbable beads. A 6-year-old German Shepherd dog underwent THR 16 months previously, which subsequently became infected. The contaminated femoral and acetabular prostheses were explanted. A femoral window was used to remove the stem and cement. The endosteal surfaces of the femur and acetabulum were reamed to remove periprosthetic tissues. The femoral window was replaced and secured in position with multiple cerclage wires. A 3.5-mm locking plate was applied to the lateral aspect of the femur to prevent fracture of the proximal femoral metaphysis and trochanter. Bioabsorbable beads of calcium sulphate, impregnated with vancomycin and gentamicin, were impacted into the femoral canal followed by an uncemented femoral stem. An uncemented acetabular implant was impacted and additional antibiotic beads placed in the vicinity prior to closure. There has been no evidence of reinfection 5 years postoperatively. Analgesic and antibacterial drugs were not required during this follow-up period; activity is unrestricted with neither lameness nor pain present. Simultaneous revision of both femoral and acetabular periprosthetic infected THR implants was successfully achieved in this patient via a single-stage procedure using uncemented implants and antibiotic-impregnated bioabsorbable beads.

Objectives The aim of this study was to describe a case of biapical tibial deformity as a result of premature distal physeal closure corrected by true spherical osteotomy, circular external skeletal fixation and distraction osteogenesis. Methods A 6-month-old male Labrador Retriever was presented for the evaluation and treatment of angular limb deformity of the left pelvic limb, with radiography and computed tomography revealing a multiplanar, biapical, compensatory tibial growth deformity, with marked distal tibial recurvatum and varus. A true spherical osteotomy was performed at the distal tibial centre of rotation of angulation (CORA), allowing for correction of the deformity in three planes, with a transverse osteotomy performed at the most proximal CORA. A circular external skeletal fixator was applied and distraction osteogenesis performed at the transverse osteotomy. Latency, distraction osteogenesis, and consolidation were performed over a 113-day period. Results At frame removal, tibial length discrepancy improved from 16.8% to 0.6% and frontal plane varus angulation improvement from 20° to 5°, when compared with the contralateral limb. Long-term evaluation revealed a satisfactory clinical and cosmetic outcome, judged by the clinician and owners, with force plate analysed symmetry index of the pelvic limb within reported normal limits. Clinical significance To our knowledge this is the first case report illustrating the value of true spherical osteotomy for the treatment of an angular limb deformity when performed in combination with distraction osteogenesis in a canine pelvic limb.

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.

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 &plusmn, 293 g and from flank was 486.8 &plusmn, 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&rsquo, s discretion and comfort.

OBJECTIVE To report the clinical application of a hemipelvic and proximal femoral endoprosthesis for limb salvage. STUDY DESIGN Retrospective case report. ANIMAL One 5-year-old, neutered female, flat coated retriever with a malignant neoplasia of the left coxofemoral joint. METHODS An invasive soft tissue mass (histiocytic sarcoma) with bone lysis of the femoral head and acetabulum was noted on radiographs, computed tomography (CT), and MRI. Custom-designed hemipelvic and proximal femoral endoprostheses were produced from CT images and manufactured with hydroxyapatite coated surfaces to allow tissue integration. The proximal femoral implant allowed tendon ongrowth and muscle attachment. The pelvic implant was anchored to the ilium and ischium with screws, and the femoral implant was cemented. Chemotherapy consisted of lomustine (CCNU). RESULTS No evidence of implant loosening or local/thoracic metastases was noted on radiographs or CT at 6 weeks and at 3, 6, 9, and 12 months after surgery. A neurapraxia resolved 14 weeks postoperatively. Intensive rehabilitation was performed. At 12 months, activity was unrestricted with minimal residual lameness. The dog was euthanized at 14 months for metastatic disease. CONCLUSION Limb salvage with a hemipelvic and proximal femoral endoprosthesis resulted in limb function and survival for 14 months. CLINICAL SIGNIFICANCE Neoplasia involving the bones of the coxofemoral joint traditionally requires hemipelvic resection and pelvic limb amputation. This report provides evidence that limb salvage can result in satisfactory levels of activity.

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.

Surgical repair of fractures and luxations of the cranial cervical vertebrae can be complicated by vertebral venous plexus hemorrhage following fracture fragment manipulation and realignment. Severe hemorrhage is potentially life threatening and may preclude definitive surgical fixation if it cannot be acceptably controlled and interferes with fixation technique. This report describes this scenario and a surgical strategy in two dogs with fractures of the second cervical vertebra. The surgical technique to limit hemorrhage included the insertion of the pins into the vertebrae, placement of collagen fleece, and autogenous cancellous bone graft over the fracture site, and while the polymethylmethacrylate cement was still within the liquid phase, axial traction was employed. The long-term outcome was considered excellent with both dogs able to ambulate unassisted and free from signs of pain. Although it is uncommon, severe vertebral venous plexus hemorrhage can occur during cervical vertebrae fracture repair. This technique provides a means to achieve internal fixation while concurrently limiting hemorrhage.

Objective This article aimed to describe the use and evolution of a synthetic osteochondral resurfacing (SOR) implant in the treatment of osteochondrosis dissecans (OCD) of the femoral condyle and to report the clinical, radiographic, computed tomography and magnetic resonance imaging outcomes of this technique. Methods Medical records of dogs that were treated with first-generation (G1) and second-generation (G2) SOR at a single institute were reviewed. Surgical reports and clinical examinations as well as the preoperative, postoperative, and follow-up radiographs, computed tomographic images and magnetic resonance imaging images were reviewed. Results Fourteen stifles (nine dogs) were included in the study. G1-SOR implants were employed in six stifles of four dogs and G2-SOR implants in eight stifles of five dogs. Osteochondrosis dissecans of the medial femoral condyle was confirmed as the sole pathology in all dogs treated with G1-SOR. Only one of eight OCD lesions was located on the medial condyle in the G2-SOR group with the remaining seven lesions affecting the lateral femoral condyle. At 12 weeks, 13 of 14 stifles displayed implant stability, with no subchondral bone changes or evidence of lucency around any implant. Eight of nine dogs achieved a good-excellent clinical outcome. Complications included one minor surgical site infection and one infective arthritis which required implant removal. Clinical Significance In this cohort of dogs, both G1-SOR and G2-SOR were successful and repeatable surgical procedures for dogs with OCD of the femoral condyle.

This article represents the outcome of a dialogue between a vet and a healthcare ethicist on the theme of ‘love’ in professional life. We focus on four types or varieties of love (eros, agape, philia and storge) in relation to the professional care of humans and animals. We discuss the relevance of Fromm’s core elements of love (care, responsibility, respect and knowledge) and consider the implications of these for human and animal health care practice. We present and respond to five arguments that might be waged against embracing love as a professional value in veterinary and medical practice. We argue that a moderated love can and should be reclaimed as a contemporary professional value. It is most helpfully contextualised within virtue ethics or care ethics. We suggest that love is a rich starting point from which to launch an exploration of an interprofessional humanimal clinical ethics.

As part of surface energy balance models used to simulate glacier melting, choosing parameterizations to adequately estimate turbulent heat fluxes is extremely challenging. This study aims to evaluate a set of four aerodynamic bulk methods (labeled as C methods), commonly used to estimate turbulent heat fluxes for a sloped glacier surface, and two less commonly used bulk methods developed from katabatic flow models. The C methods differ in their parameterizations of the bulk exchange coefficient that relates the fluxes to the near-surface measurements of mean wind speed, air temperature, and humidity. The methods' performance in simulating 30 min sensible- and latent-heat fluxes is evaluated against the measured fluxes from an open-path eddy-covariance (OPEC) method. The evaluation is performed at a point scale of a mountain glacier, using one-level meteorological and OPEC observations from multi-day periods in the 2010 and 2012 summer seasons. The analysis of the two independent seasons yielded the same key findings, which include the following: first, the bulk method, with or without the commonly used Monin–Obukhov (M–O) stability functions, overestimates the turbulent heat fluxes over the observational period, mainly due to a substantial overestimation of the friction velocity. This overestimation is most pronounced during the katabatic flow conditions, corroborating the previous findings that the M–O theory works poorly in the presence of a low wind speed maximum. Second, the method based on a katabatic flow model (labeled as the KInt method) outperforms any C method in simulating the friction velocity; however, the C methods outperform the KInt method in simulating the sensible-heat fluxes. Third, the best overall performance is given by a hybrid method, which combines the KInt approach with the C method; i.e., it parameterizes eddy viscosity differently than eddy diffusivity. An error analysis reveals that the uncertainties in the measured meteorological variables and the roughness lengths produce errors in the modeled fluxes that are smaller than the differences between the modeled and observed fluxes. This implies that further advances will require improvement to model theory rather than better measurements of input variables. Further data from different glaciers are needed to investigate any universality of these findings.

Objective To determine the biomechanical behavior of a novel distraction-stabilization system, consisting of an intervertebral distraction bolt, polyaxial screws, and connecting rods, in the canine lumbosacral spine. Study design Biomechanical study. Sample population Cadaveric canine lumbosacral spines (L4-Cd3) (N = 8). Methods Cadaveric lumbosacral spines were harvested, stripped of musculature, mounted on a 4-point bending jig, and tested in extension, flexion, and lateral bending using nondestructive compressive axial loads (0-150 N). Angular displacement was recorded from reflective optical trackers rigidly secured to L6, L7, and S1. Data for primary and coupled motion were collected from intact spines, after destabilization at L7-S1, and following surgical stabilization with the new implant system. Results As compared with the intact spine, laminectomy resulted in a modest increase in angular displacement at L6-L7 and a marked increase at L7-S1. Instrumentation significantly reduced motion at the operated level (L7-S1) with a concomitant increase at the adjacent level (L6-L7). Conclusion The combination of a polyaxial pedicle screw-rod system and intervertebral spacer provides a versatile solution of surgical stabilization of the lumbosacral joint following surgical decompression in the canine lumbosacral spine. The increase in motion at L6-L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question. Clinical relevance These results support the feasibility of using this new implant system for the management of degenerative lumbosacral disease in dogs. The increase in motion at L6-L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question.

The application of optimum contact force (CF) can be used to improve ablation procedure success and safety. The lesion size index (LSI) is a novel dimensionless contact force parameter that allows for an accurate estimation of lesion volume in real time by integrating contact force (grams), duration (seconds) and power (watts). The aim was to correlate LSI values with current contact force parameters to achieve successful and safe bidirectional block of the cavotricuspid isthmus (CTI) using a maximum voltage-guided (MVG) ablation strategy. Fifteen consecutive patients (age 69 ± 7.9 years, nine males) with symptomatic atrial flutter (AFL) were evaluated and compared with 23 control (age 66.3 ± 10.4 years, 16 males) non-contact force-guided ablation cases. Irrigated-tip force-sensing ablation catheters (TactiCath Quartz™, St. Jude Medical, St. Paul, MN, USA) were used in the CF group to achieve the primary endpoint of complete bidirectional block of the isthmus. In the CF group, a total of 233 radiofrequency (RF) applications were examined. A mean LSI of 6.4 ±1.0 correlated with a force-time integral (FTI) of 581.2 ±230.9 g/s and an average CF of 13.9 ±4.9 g concurrently. Intraprocedural, fluoroscopy time and RF time demonstrated lower trends in the CF group, but no significance with respect to these trends was observed. The secondary endpoint of no reconnection within 20 min after the procedure was equally attained in both groups, and, likewise, the level of safety was comparable. An LSI value of >5 represents a new effective parameter in MVG ablation for the cavotricuspid region that demonstrates a safe profile. Guidance of CTI ablation using LSI and other contact force parameters of CF 13.9 ±4.9 g and FTI 581.2 ±230.9 g/s demonstrated highly effective and safe outcomes.

Due to the frequency of cervical spine injuries in canines, the purpose of this effort was to develop an EMG-driven dynamic model of the canine cervical spine to assess a biomechanical understanding that enables one to investigate the risk of neck disorders. A canine subject was recruited in this investigation in order to collect subject specific data. Reflective markers and a motion capture system were used for kinematic measurement; surface electrodes were used to record electromyography signals, and with the aid of force plate kinetics were recorded. A 3D model of the canine subject was reconstructed from an MRI dataset. Muscles lines of action were defined through a new technique with the aid of 3D white light scanner. The model performed well with a 0.73 weighted R2 value in all three planes. The weighted average absolute error of the predicted moment was less than 10% of the external moment. The proposed model is a canine specific forward-dynamics model that precisely tracks the canine subject head and neck motion, calculates the muscle force generated from the twelve major moment producing muscles, and estimates resulting loads on specific spinal tissues.

Degenerative lumbosacral stenosis has been suspected to have a dynamic component, especially regarding encroachment of the L7 nerve roots exiting the lumbosacral foramina. Angled cross-sectional imaging of the neuroforamina has been found improve the accuracy of the diagnosis of stenosis in humans. In this anatomic study, foraminal apertures were evaluated by MRI at the entry, middle, and exit zones of the nerve roots in 30 dogs that were clinically affected by lumbosacral disease. Standard vs. oblique planar orientation and neutral vs. hyperextended positioning of the lumbosacral area were compared by measuring the median values for entry, middle, and exit zones. The neuroforaminal area acquired using oblique plane acquisition was significantly smaller than standard parasagittal measurements. Furthermore, standard parasagittal neuroforaminal dimensions in the hyperextended position were significantly smaller than standard parasagittal measurements in the neutral position. This statistical difference was even more pronounced for neuroforaminal dimension evaluated in the oblique plane and hyperextended position. Positioning of the dog during imaging has a significant effect on neuroforaminal dimension, corroborating the notion that spinal position may influence neural claudication in clinically affected patients. Reductions in neuroforaminal dimension are more evident on oblique planar image acquisition, suggesting that this approach may be more useful than parasagittal imaging as a tool for identifying subtle changes in L7 neuroforaminal dimensions in cases of canine lumbosacral stenosis.

Background Disregarding atlantoaxial instability in toy breed dogs associated with dens malformation and cervical spondylomyelopathy; cervical vertebral malformations are rare and poorly characterised in veterinary medicine and consequently treatment strategies and clinical outcome are sparsely documented. Results Electronic clinical records at our veterinary referral hospital between April 2009 and November 2018 were searched for patients presented with cervical myelopathy secondary to an underlying suspected vertebral malformation/instability. Nine dogs met the inclusion criteria. Two dogs were diagnosed with atlantoaxial pseudoarthrosis, two dogs with a syndrome similar to Klippel-Feil in humans, two dogs with congenital cervical fusion, two dogs with congenital C2-C3 canal stenosis and deficiencies of the dorsal arch of the atlas and laminae of the axis and one with axial rotatory displacement. Tetraparesis, proprioceptive deficits, cervical hyperesthesia and cervical scoliosis were the most common clinical signs. The axis was the most commonly affected vertebrae (8/9 patients). Patients diagnosed with Klippel-Feil-like Syndrome were the younger (average of 262.5 days) and patients diagnosed with fused vertebrae the oldest (average of 2896 days) in our studied population (average of 1580.8 days). Conclusion Cervical vertebral malformations are rare, or alternatively, being underdiagnosed in veterinary medicine. Patients diagnosed with Klippel-Feil-like Syndrome had a successful medium and long-term outcome with conservative management. Surgical treatment was often indicated for the other conditions presented in this study due to spinal instability and/or myelopathy. Stabilisations via ventral approaches were revealed to be safe. Multicentre and prospective studies are necessary in veterinary medicine to better characterise clinical outcomes in cervical vertebral malformations.