Anatomical classification of feline congenital extrahepatic portosystemic shunts based on CT angiography: A SVSTS and VIRIES multi-institutional study in 231 cats.

The prevalence of anatomical-based subtypes of feline congenital extrahepatic portosystemic shunts (EHPSS) has not been completely elucidated. The goal of this study was to use CT angiography to create an anatomical-based nomenclature system for feline congenital EHPSS. Additionally, subjective portal perfusion scores were generated to determine if intrinsic portal vein development was associated with different shunt conformations or patient age at the time of CT. The SVSTS and VIRIES list services were used to recruit cases. Data collected included patient DOB, gender, breed, weight, CT date, and reported diagnosis. Shunts were classified based upon (1) the shunt portal vessel(s) of origin, (2) the shunt systemic vessel(s) of insertion, and (3) any substantial portal vessels contributing to the shunt. Additionally, hepatic portal perfusion was subjectively scored between 1 (poor/none) and 5 (good/normal) based on the caliber of the intrahepatic PVs. A total of 264 CT scans were submitted from 29 institutions. Due to exclusion criteria, 33 (13%) were removed, leaving 231 CT scans to be included. Twenty-five different EHPSS anatomies were identified with five classifications accounting for 78% of all shunts (LGP [53%], LGC-post [11%], LCG [7%], LGC-pre [4%], and PC [4%]). Shunt origin involved the left gastric vein in 75% of the described classifications. Significant differences were identified among the five most common shunt types with respect to age at the time of CT scan (P = .002), breed (P < .001), and subjective portal perfusion score (P < .001). This refined anatomical classification system for feline EHPSS may enable improved understanding, treatment comparisons, and outcome prediction for cats with these anomalies.

Usefulness of serum amyloid A for the diagnosis of pyelonephritis in cats: A prospective evaluation.

BACKGROUND: The diagnosis of pyelonephritis in cats is challenging and development of a noninvasive and accurate biomarker is needed. HYPOTHESES: Serum amyloid A (SAA) is increased in cats with pyelonephritis, but not in cats with other urinary tract diseases. ANIMALS: A cohort of 125 cats (149 observations). METHODS: This was a prospective study. Group 1 included cats with a diagnosis of pyelonephritis either confirmed by bacterial culture of pelvic urine (Group 1a) or presumed (1b). Group 2 included cats for which pyelonephritis was ruled out (with certainty: Group 2a or judged unlikely: Group 2b). SAA concentration was compared between groups, and accuracy of SAA for the diagnosis of pyelonephritis was calculated using a Receiver Operating Characteristic (ROC) curve analysis. RESULTS: Median SAA concentration was significantly higher in Group 1a (86.8 mg/L [73.3; 161.5]; n = 8) than in Group 2a (4 mg/L [1.8; 5.6], n = 19; P < .001) and in Group 2b (5.4 mg/L [3.1; 9.7], n = 113; P < .001). It was also significantly higher in Group 1b (98.8 mg/L [83.1; 147.3]; n = 9) than in Group 2b (P < .001) and Group 2a (P < .001). Optimal diagnostic cut-off for SAA concentration was 51.3 mg/L. yielding a sensitivity of 88% (95% confidence interval: [64%; 99%]) and a specificity of 94% (95% confidence interval: [88%; 97%]). CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of SAA could be used to rule out pyelonephritis in the case of low suspicion of the disease. Increased SAA concentration is suggestive of pyelonephritis despite a lack of specificity.

Locking conical coupling plates in small animal orthopedics: A review.

Conical coupling locking plates (CCP) have become an interesting alternative in veterinary orthopedics and traumatology. Available data in this regard, however, must be interpreted with caution, and several studies are still required to reach definitive conclusions on the clinical use of these implants. In this context, this review aims to discuss CCP applications and mechanical aspects in small animals and summarize in vivo, in vitro and ex vivo study results.

3D-Printed Osteoinductive Polymeric Scaffolds with Optimized Architecture to Repair a Sheep Metatarsal Critical-Size Bone Defect.

The reconstruction of critical-size bone defects in long bones remains a challenge for clinicians. A new osteoinductive medical device is developed here for long bone repair by combining a 3D-printed architectured cylindrical scaffold made of clinical-grade polylactic acid (PLA) with a polyelectrolyte film coating delivering the osteogenic bone morphogenetic protein 2 (BMP-2). This film-coated scaffold is used to repair a sheep metatarsal 25-mm long critical-size bone defect. In vitro and in vivo biocompatibility of the film-coated PLA material is proved according to ISO standards. Scaffold geometry is found to influence BMP-2 incorporation. Bone regeneration is followed using X-ray scans, µCT scans, and histology. It is shown that scaffold internal geometry, notably pore shape, influenced bone regeneration, which is homogenous longitudinally. Scaffolds with cubic pores of ≈870 µm and a low BMP-2 dose of ≈120 µg cm-3 induce the best bone regeneration without any adverse effects. The visual score given by clinicians during animal follow-up is found to be an easy way to predict bone regeneration. This work opens perspectives for a clinical application in personalized bone regeneration.

A Case of Urinary Bladder Malakoplakia in a Young French Bulldog: Diagnostic and Therapeutic Issues.

A 3-month-old female French Bulldog presented with hematuria, severe pollakiuria, and urinary incontinence lasting for 1.5 months. Broad-spectrum empirical antibiotic therapy and nonsteroidal anti-inflammatory drugs were initiated by the referring veterinarian. Due to a lack of improvement, the dog was referred. At referral examination, urinary clinical signs persisted (hematuria, severe pollakiuria) and a firm bladder was noted. Abdominal ultrasonography revealed severe, diffuse bladder wall thickening with a significant reduction in the bladder lumen. Urinary tract endoscopy showed whitish exophytic proliferations throughout the entire bladder wall. Histological bladder wall analysis led to a diagnosis of bladder malakoplakia. Prolonged antibiotic therapy with fluoroquinolones was prescribed and resulted in clinical remission despite persistent bacteria in the bladder wall. This report describes a case of successfully medically managed bladder malakoplakia, a very rare condition in veterinary medicine, well documented in humans.

A wear model to predict damage of reconstructed ACL.

Impingement with surrounding tissues is a major cause of failure of anterior cruciate ligament reconstruction. However, the complexity of the knee kinematics and anatomical variations make it difficult to predict the occurrence of contact and the extent of the resulting damage. Here we hypothesise that a description of wear between the reconstructed ligament and adjacent structures captures the in vivo damage produced with physiological loadings. To test this, we performed an in vivo study on a sheep model and investigated the role of different sources of damage: overstretching, excessive twist, excessive compression, and wear. Seven sheep underwent cranial cruciate ligament reconstruction using a tendon autograft. Necropsy observations and pull-out force measurements performed postoperatively at three months showed high variability across specimens of the extent and location of graft damage. Using 3D digital models of each stifle based on X-ray imaging and kinematics measurements, we determined the relative displacements between the graft and the surrounding bones and computed a wear index describing the work of friction forces underwent by the graft during a full flexion-extension movement. While tensile strain, angle of twist and impingement volume showed no correlation with pull-out force (ρ = -0.321, p = 0.498), the wear index showed a strong negative correlation (r = -0.902, p = 0.006). Moreover, contour maps showing the distribution of wear on the graft were consistent with the observations of damage during the necropsy. These results demonstrate that wear is a good proxy of graft damage. The proposed wear index could be used in implant design and surgery planning to minimise the risk of implant failure. Its application to sheep can provide a way to increase preclinical testing efficiency.

Surgically treated congenital cleft palate in a 4-month-old kitten: medium-term clinical and CT assessment.

Case summary: A 4-month-old female domestic shorthair kitten was presented for a congenital cleft palate causing nasal discharge and sneezing episodes. CT revealed a palatal bone defect involving 20% of the palatal area. Surgical correction of both the hard and soft palate defects was performed using the overlapping and medially positioned flap techniques, respectively. Complete healing of the wound and full resolution of the clinical signs occurred within a 1-month period. At 2 months postoperatively, two punctiform oronasal fistulae were observed rostrally without associated clinical signs. Control CT, performed 6 months postoperatively, revealed a 50% enlargement of the palatal bone defect. At 12 months postoperatively, the cat was still in good general condition without any clinical signs. Relevance and novel information: To the best of our knowledge, this is the first report to describe the treatment of a congenital cleft palate in a kitten using the overlapping flap technique with a successful medium-term clinical outcome, despite the formation of two oronasal fistulae. This suggests that, as in dogs, full restoration of oronasal compartmentation is not mandatory to achieve functional outcome. The increase of the palatal bone defect over time may play a role in late oronasal fistulae formation and should be considered for surgical planning.

Outcomes of 25 female dogs treated for ectopic ureters by open surgery or cystoscopic-guided laser ablation.

OBJECTIVE: To report outcomes after the correction of ectopic ureter (EU) by open surgery or cystoscopic-guided laser ablation (CLA) in female dogs. STUDY DESIGN: Retrospective study from 2011 to 2018. ANIMALS: Twenty-five female dogs. METHODS: Data collected included signalment, clinicopathologic data, procedural data, complications, and short-term and long-term outcomes. Complications were graded as minor or major if a surgical revision was required. Continence status was scored subjectively (1 = completely incontinent to 10 = fully continent). RESULTS: Fifteen dogs had bilateral EU and 24 had intramural EU (iEU). Open surgical correction included 13 neoureterostomies, 2 neocystoureterostomies, and a combination of these in 2 dogs. Eight dogs underwent CLA. Eighteen dogs experienced minor complications (72%), and 2 experienced major complications (8%). One-month postoperative continence was achieved in 20/25 (80%) dogs (median score of 10). Incontinence recurred at a median time of 24.9 months in 5 dogs but responded to medical treatment. Overall, dogs remained continent for 66 months (median) and 22/25 (88%) dogs achieved continence with adjunction of medical/surgical treatment in incontinent ones. Fewer minor complications and postoperative recurrences of incontinence were documented after CLA than neoureterostomy (P < .01 and P < .05). CONCLUSION: Ectopic ureter correction by open surgery or CLA resulted in a subjectively good prognosis, most dogs reaching continence within a month of surgery, although incontinence occasionally recurred in the long term. CLA was associated with fewer complications and incontinence recurrences than neoureterostomy. CLINICAL SIGNIFICANCE: Cystoscopic-guided laser ablation should be preferred to correct iEU to prevent short-term complications and the recurrence of incontinence. Further studies should investigate the cause of postoperative recurrence of urinary incontinence.

Long-term follow-up of a juvenile simple renal cyst in a dog treated by laparoscopic deroofing, fulguration, and omentalization.

CASE DESCRIPTION: A 10-month-old male crossbred dog presented with a 4-week history of polyuria and polydipsia and a 6-month history of vomiting. CLINICAL FINDINGS: Clinical examination revealed abdominal pain and right-sided nephromegaly. Biochemistry was within normal limits. Diagnostic imaging showed a well-defined, unilateral renal mass containing anechoic fluid consistent with a simple renal cyst (SRC). TREATMENT AND OUTCOME: The cyst was drained under ultrasonographic guidance but recurred 3 months later, concomitant with recurrence of the previously reported clinical signs. The cyst was then deroofed, fulgurated, and omentalized under laparoscopy by use of a 3-port technique. The resected cystic wall was histopathologically consistent with an SRC, presumptively congenital. The dog showed a good recovery with resolution of clinical signs. Renal function was normal at last follow-up, conducted 2 years postoperatively, without evidence of recurrent disease. CLINICAL RELEVANCE: To our knowledge, this was the first report of a symptomatic juvenile SRC of presumptively congenital origin in a dog treated successfully by laparoscopic deroofing, fulguration, and omentalization. The polyuria, polydipsia, chronic vomiting, and abdominal pain may all have been related to space-occupying effects of the cyst, as these symptoms resolved post-treatment. Results of long-term follow-up advocate for this durable cure of SRC by use of laparoscopic procedures, especially when compared to simple drainage of the cyst, as the latter initially failed in the present case.

Remnants-preserving ACL reconstruction using direct tendinous graft fixation: a new rat model.

BACKGROUND: Anterior cruciate ligament (ACL) repair techniques are new emerging strategies prevailing, in selected cases, over standard reconstruction of the ACL with excision of its remnants. Mid-substance ACL tears represent a challenge for ACL repair techniques, and remnants-preserving ACL reconstruction (rp-ACLR) using an autograft remains the recommended treatment in this situation. However, morbidity associated with the autograft harvesting prompts the need for alternative surgical strategies based on the use of synthetic scaffolds. Relevant small animal models of mid-substance tears with ACL remnants preservation and reconstruction are necessary to establish the preliminary proof of concept of these new strategies. METHODS: A rat model of rp-ACLR using a tendinous autograft after complete mid-substance ACL transection was established. Twelve weeks following surgery, clinical outcomes and knee joints were assessed through visual gait analysis, Lachman tests, thigh perimeter measurements, magnetic resonance imaging, micro-computed tomography, and histology, to evaluate the morbidity of the procedure, accuracy of bone tunnel positioning, ACL remnants fate, osteoarthritis, and autograft bony integration. Results were compared with those obtained with isolated ACL transection without reconstruction and to right non-operated knees. RESULTS AND DISCUSSION: Most operated animals were weight-bearing the day following surgery, and no adverse inflammatory reaction has been observed for the whole duration of the study. Autograft fixation with cortical screws provided effective graft anchorage until sacrifice. Healing of the transected ACL was not observed in the animals in which no graft reconstruction was performed. rp-ACLR was associated with a reduced degeneration of the ACL remnants (p = 0.004) and cartilages (p = 0.0437). Joint effusion and synovitis were significantly lower in the reconstructed group compared to the transected ACL group (p = 0.004). Most of the bone tunnel apertures were anatomically positioned in the coronal and/or sagittal plane. The most deviated bone tunnel apertures were the tibial ones, located in median less than 1 mm posteriorly to anatomical ACL footprint center. CONCLUSION: This study presents a cost-effective, new relevant and objective rat model associated with low morbidity for the preliminary study of bio-implantable materials designed for remnants-preserving ACL surgery after mid-substance ACL tear.

Preventive Moderate Continuous Running-Exercise Conditioning Improves the Healing of Non-Critical Size Bone Defects in Male Wistar Rats: A Pilot Study Using µCT.

Although physical exercise has unquestionable benefits on bone health, its effects on bone healing have been poorly investigated. This study evaluated the effects of preemptive moderate continuous running on the healing of non-critical sized bone defects in rats by µCT. We hypothesized that a preemptive running exercise would quicken bone healing. Twenty 5-week-old, male, Wistar rats were randomly allocated to one of the following groups (n = 10): sedentary control (SED) or continuous running (EX, 45 min/d, 5 d/week at moderate speed, for 8 consecutive weeks). A 2 mm diameter bone defect was then performed in the right tibia and femur. No exercise was performed during a 4 week-convalescence. Healing-tissue trabecular microarchitectural parameters were assessed once a week for 4 weeks using µCT and plasma bone turnover markers measured at the end of the study protocol (time point T12). At T12, bone volume fraction (BV/TV; BV: bone volume, TV: tissue volume) of the healing tissue in tibiae and femurs from EX rats was higher compared to that in SED rats (p = 0.001). BV/TV in EX rats was also higher in tibiae than in femurs (p < 0.01). The bone mineral density of the healing tissue in femurs from EX rats was higher compared to that in femurs from SED rats (p < 0.03). N-terminal telopeptide of collagen type I in EX rats was decreased compared to SED rats (p < 0.05), while no differences were observed for alkaline phosphatase and parathyroid hormone. The study provides evidence that preemptive moderate continuous running improves the healing of non-critical sized bone defects in male Wistar rats.

Symptomatic lateral ventricular cystic lesion in a young cat.

CASE SUMMARY: A 1.5-year-old male neutered Persian cat was referred for acute deterioration of chronic left head tilt and ataxia. A lateral intraventricular cystic lesion, closely associated with the left choroid plexus, was identified on MRI. The intralesional signal intensity and cytological analysis of the fluid revealed a liquid similar to cerebrospinal fluid. After trepanation, an endoscopic-assisted fenestration and aspiration of the cyst were performed to temporally relieve the high intracranial pressure while waiting for surgical cystoperitoneal shunt placement. Three weeks after surgery, clinical relapse and recurrence of the lesion were noted on the pre-cystoperitoneal shunting MRI. During anaesthesia, the cat arrested. Cardiac resuscitation was successfully performed and cystoperitoneal shunting was postponed. Global brain ischaemia was then suspected, based on major forebrain clinical signs and MRI abnormalities. During a 6-month recovery period, a further three fine-needle CT-guided aspirations of the lesion were required, owing to clinical recurrence and increased cyst size. Cystoperitoneal shunting was eventually performed, allowing persistent reduction of the lesion and long-term improvement of the cat's neurological status. RELEVANCE AND NOVEL INFORMATION: This is the first report of a symptomatic lateral intraventricular cystic lesion in a cat. A left lateral intraventricular choroid plexus cyst was suspected based on the MRI features. Our case suggests that endoscopic fenestration and CT-guided aspiration are not adequate treatments for long-term management. Cystoperitoneal shunting may be a safe procedure, allowing significant and stable reduction of the cystic lesion, associated with improvement in the cat's neurological status by preventing high intracranial pressure.

Custom-made macroporous bioceramic implants based on triply-periodic minimal surfaces for bone defects in load-bearing sites.

The architectural features of synthetic bone grafts are key parameters for regulating cell functions and tissue formation for the successful repair of bone defects. In this regard, macroporous structures based on triply-periodic minimal surfaces (TPMS) are considered to have untapped potential. In the present study, custom-made implants based on a gyroid structure, with (GPRC) and without (GP) a cortical-like reinforcement, were specifically designed to fit an intended bone defect in rat femurs. Sintered hydroxyapatite implants were produced using a dedicated additive manufacturing technology and their morphological, physico-chemical and mechanical features were characterized. The implants' integrity and ability to support bone ingrowth were assessed after 4, 6 and 8 weeks of implantation in a 3-mm-long, femoral defect in Lewis rats. GP and GPRC implants were manufactured with comparable macro- to nano-architectures. Cortical-like reinforcement significantly improved implant effective stiffness and resistance to fracture after implantation. This cortical-like reinforcement also concentrated new bone formation in the core of the GPRC implants, without affecting newly formed bone quantity or maturity. This study showed, for the first time, that custom-made TPMS-based bioceramic implants could be produced and successfully implanted in load-bearing sites. Adding a cortical-like reinforcement (GPRC implants) was a relevant solution to improve implant mechanical resistance, and changed osteogenic mechanism compared to the GP implants. STATEMENT OF SIGNIFICANCE: Architectural features are known to be key parameters for successful bone repair using synthetic bioceramic bone graft. So far, conventional manufacturing techniques, lacking reproducibility and complete control of the implant macro-architecture, impeded the exploration of complex architectures, such as triply periodic minimal surfaces (TPMS), which are foreseen to have an unrivaled potential for bone repair. Using a new additive manufacturing process, macroporous TPMS-based bioceramics implants were produced in calcium phosphate, characterized and implanted in a femoral defect in rats. The results showed, for the first time, that such macroporous implants can be successfully implanted in anatomical load-bearing sites when a cortical-like outer shell is added. This outer shell also concentrated new bone formation in the implant center, without affecting new bone quantity or maturity.

Hydrogel-Tissue Adhesion Using Blood Coagulation Induced by Silica Nanoparticle Coatings.

The fixation of hydrogels to biological tissues is a major challenge conditioning the development of implants and surgical techniques. Here, coatings of procoagulant nanoparticles are devised which use the presence of blood to create adhesion between hydrogels and soft internal organs. Those nanostructured coatings are simply adsorbed at the hydrogel surfaces and can rapidly activate the formation of an interfacial blood clot acting as an adhesive joint. This concept is demonstrated on pig liver capsules with model poly(ethylene-glycol) membranes that are intrinsically poorly adhesive. In the absence of blood, ex vivo peeling tests show that coatings with aggregates of bare silica nanoparticles induce a 2- to 4-fold increase in adhesion energy as compared to the uncoated membrane (3 ± 2 J m-2). This effect is found to scale with the specific surface area of the coating. The highest adhesion energies produced by these nanoparticle-coated membranes (10 ± 5 J m-2) approach the value obtained with cyanoacrylate glue (33 ± 11 J m-2) for which tearing of the tissue is observed. Ex vivo pull-off tests show an adhesion strength of coated membranes around 5 ± 1 kPa, which is significantly reduced when operating in vivo (1.0 ± 0.5 kPa). Nevertheless, when blood is introduced at the interface, the in vivo adhesion strength can be improved remarkably with silica coatings, reaching 4 ± 2 kPa after 40 min contact. In addition, these silica-coated membranes can seal and stop the bleeding produced by liver biopsies very rapidly (<30 s). Such a combination of coagulation and particle bridging opens promising routes for better biointegrated hydrogel implants and improved surgical adhesives, hemostats, and sealants.

Primary hyperparathyroidism due to a cystic parathyroid adenoma in a cat.

A 15-year-old neutered female domestic shorthair cat was presented for weight loss, polydipsia/polyuria, and lethargy. A large fluctuant mass was palpated in the ventral right cervical region. Biochemistry results were consistent with primary hyperparathyroidism. Parathyroid hormone level in the fluid was higher to that observed in the plasma, consistent with a cystic parathyroid lesion. Right parathyroidectomy and thyroidectomy were performed without complications. Ionized calcium normalized within a few hours. Histopathology yielded a diagnosis of cystic parathyroid adenoma. Follow-up showed complete recovery of clinical signs and normalization of ionized calcium. This case shows an uncommon presentation of feline primary hyperparathyroidism secondary to a cystic parathyroid adenoma and is, to our knowledge, the first case presented with a large palpable mass in which parathyroid hormone concentration was measured. This report highlights the value of selective hormonal analyses of the cystic fluid to confirm the origin of the cystic lesion pre-operatively.

Interfacial fluid transport is a key to hydrogel bioadhesion.

Attaching hydrogels to soft internal tissues is a key to the development of a number of biomedical devices. Nevertheless, the wet nature of hydrogels and tissues renders this adhesion most difficult to achieve and control. Here, we show that the transport of fluids across hydrogel-tissue interfaces plays a central role in adhesion. Using ex vivo peeling experiments on porcine liver, we characterized the adhesion between model hydrogel membranes and the liver capsule and parenchyma. By varying the contact time, the tissue hydration, and the swelling ratio of the hydrogel membrane, a transition between two peeling regimes is found: a lubricated regime where a liquid layer wets the interface, yielding low adhesion energies (0.1 J/m2 to 1 J/m2), and an adhesive regime with a solid binding between hydrogel and tissues and higher adhesion energies (1 J/m2 to 10 J/m2). We show that this transition corresponds to a draining of the interface inducing a local dehydration of the tissues, which become intrinsically adhesive. A simple model taking into account the microanatomy of tissues captures the transition for both the liver capsule and parenchyma. In vivo experiments demonstrate that this effect still holds on actively hydrated tissues like the liver capsule and show that adhesion can be strongly enhanced when using superabsorbent hydrogel meshes. These results shed light on the design of predictive bioadhesion tests as well as on the development of improved bioadhesive strategies exploiting interfacial fluid transport.

Effect of the Bone Morphogenetic Protein-2 Doses on the Osteogenic Potential of Human Multipotent Stromal Cells- Containing Tissue Engineered Constructs.

IMPACT STATEMENT: A strategy for improving the efficacy of stem cell-based bone tissue engineering (TE) constructs is to combine bone morphogenetic protein-2 (BMP-2) with multipotent stromal cells (MSC). Previous studies on the potential cooperative effect of BMP-2 with human multipotent stromal cells (hMSCs) on bone formation in vivo have, however, shown contradictory results likely due to the various and/or inappropriate BMP-2 doses. Our results provided evidence that the addition of BMP-2 at low dose only was beneficial to improve the osteogenic potential of hMSCs-containing TE constructs, whereas BMP-2 delivered at high dose overcame the advantage of combining this growth factor with hMSCs. This new knowledge will help in designing improved combination strategies for tissue regeneration with better clinical outcomes.

Reproducibility, Accuracy and Effect of Autoclave Sterilization on a Thermoplastic Three-Dimensional Model Printed by a Desktop Fused Deposition Modelling Three-Dimensional Printer.

OBJECTIVES: The main purpose of this study was to determine the reproducibility and accuracy of a three-dimensional (3D) bone model printed on a desktop 3D-printer based on fused deposition modelling (FDM) technology with polylactic acid (PLA) and the effect of autoclave sterilization on the printed models. METHODS: Computed tomographic images of the tibia were obtained from 10 feline cadavers, used to create a bone surface-rendering file and sent to the 3D printing software. Right and left tibias were each printed five times with the FDM desktop 3D printer using PLA plastic material. Plastic models and cadaveric bones were measured with a profile projector device at six predetermined landmarks. Plastic bones were then sterilized using an autoclave before being re-measured applying the same method. Analyses of printed model size reliability were conducted using intra-class correlation coefficients (ICC) and Bland-Altman plots. RESULTS: The ICC always showed an almost perfect agreement when comparing 3D-printed models issued from the same cadaveric bone. The ICC showed moderate agreement for one measurement and strong/perfect agreement for others when comparing a cadaveric bone with the corresponding 3D model. Concerning the comparison of the same 3D-printed model, before and after sterilization, ICC showed either strong or perfect agreement. CLINICAL SIGNIFICANCE: Rapid-prototyping with our FDM desktop 3D-printer using PLA was an accurate, a reproducible and a sterilization-compliant way to obtain 3D plastic models.

Ultrasonography is more accurate than percutaneous palpation for identifying targeted thoracolumbar intervertebral disc spaces in dogs.

During minimally invasive spinal surgery, correct identification of the affected intervertebral disc space is critical. Percutaneous palpation is commonly used, but results may be unreliable. Fluoroscopy is the gold standard but can be cumbersome and exposes operators to ionizing radiation. Spinal ultrasound has been described in veterinary medicine and could be a feasible alternative. This prospective, methods comparison study mimicked a minimally invasive spinal surgery in 10 canine cadavers and compared the accuracy of ultrasound and percutaneous palpation for thoracolumbar intervertebral disc space identification, using fluoroscopy as the reference standard. For each experiment, a disc space was randomly chosen. Identification was then attempted using both percutaneous palpation and ultrasound. For ultrasound, a linear probe was used to guide the operator to the correct location. The time necessary to perform each method was recorded. Accuracies for each method were calculated and statistically compared. Effects of body condition score, location of the targeted thoracolumbar intervertebral disc space and learning curve for each method were also evaluated. Ultrasonographic identification was more accurate (96.7% vs. 76.7%; P < 0.03) but took longer (147 s vs. 29 s; P < 0.0001) than percutaneous palpation. Findings from this cadaver study indicated that percutaneous palpation alone had low accuracy for correctly identifying a targeted thoracolumbar intervertebral disc space and supported the use of ultrasound as a method for improving the accuracy. Future studies are needed to assess the method in clinical cases, especially in obese dogs and/or those in which the targeted site is distant from palpable anatomical landmarks.