Pilot Clinical Trial to Evaluate In Situ Calcium Phosphate Cement Injection for Conservative Surgical Management of Appendicular Osteosarcoma in Dogs.

Cementoplasty is a minimally invasive procedure that consists of injecting a bone substitute into the tumor lesion to provide bone reinforcement and alleviate pain. This study aimed to demonstrate the feasibility, safety, and efficacy of cementoplasty with a calcium phosphate cement in osteosarcoma to reduce pain and preserve limb function. Throughout the 6-month study, dogs received no adjuvant therapy, and dogs' evaluations included a clinical examination, monitoring of postoperative complications, radiographic follow-up, and assessment of limb function and pain scores. Out of 12 dogs enrolled, 10 were withdrawn before study completion due to deterioration in their general condition. Nine (9) dogs were followed until D28, six until D56, and two until D183. Compared to D0, more than 50% of the dogs showed improvement in both veterinarian and owner scores at their final visit. Throughout the study, 10 major and 4 minor complications were reported, all unrelated to the procedure. This open non-controlled study provides first evidence of the feasibility, safety, and efficacy of cementoplasty procedure using a calcium phosphate bone cement to relieve pain and preserve limb function in dogs suffering from appendicular osteosarcoma.

Long-term outcomes after arthroscopic treatment of dogs affected by osteochondrosis dissecans of the humeral trochlea, with or without medial coronoid disease: 23 cases (2012-2020).

The objective of this study was to report long-term clinical and radiographic outcomes following arthroscopic reparative treatment - flap removal, curettage, and osteostixis of subchondral bone - in dogs with humeral trochlea osteochondritis dissecans (OCD). Dogs were included in this retrospective multicenter case series if they had a computed tomography diagnostic of humeral trochlear OCD, with or without medial coronoid disease, that was treated by arthroscopic reparative technique, and a detailed follow-up at least 6 mo postoperatively. The latter included a clinical examination, assessment of lameness, measurement of the brachial circumference and elbow amplitude, International Elbow Working Group (IEWG) radiographic score, owner-completed canine brief pain inventory (CBPI) score, and visual analogue scale (VAS) rating. A generalized linear model and tests for symmetry and marginal homogeneity were used to compare data. Twenty-three dogs (30 affected elbows) were included. Long-term (median: 22 mo; range: 6 to 98 mo) postoperative lameness, CBPI, VAS, joint distension, and pain scores were significantly improved compared with the preoperative values. Long-term postoperative range of motion and brachial circumference did not reveal any significant difference between OCD-affected and unaffected elbows. Long-term IEWG scores were similar to preoperative values in 56% of elbows and had progressed by 1 grade in 44%. Long-term complications included persistent Grade-1 lameness and occurred in 23% of dogs. Long-term outcomes based on lameness and CBPI scores were considered excellent in 67% of dogs, good in 27%, and intermediate in 6%. Arthroscopic treatment is thus a suitable surgical procedure for OCD of the humeral trochlea in dogs and provides good long-term results.

Cette étude rapporte les résultats cliniques et radiographiques à long terme après un traitement arthroscopique chez des chiens atteints d'ostéochondrite disséquante (OCD) de la trochlée humérale. Les chiens inclus ont reçu un diagnostic d'OCD de la trochlée humérale par tomographie, un traitement réparateur par arthroscopie et un suivi post-opératoire d'au moins 6 mois. Ce dernier comprenant un examen clinique et orthopédique, la mesure de la circonférence brachiale et de l'amplitude du coude, le score radiographique de l'International Elbow Working Group (IEWG), le score Canine Brief Pain Inventory (CBPI) et l'échelle visuelle analogique (EVA). Un modèle linéaire généralisé et des tests de symétrie et d'homogénéité marginale ont permis de comparer les données. Vingt-trois chiens (30 coudes affectés) ont été inclus. Les scores postopératoires à long terme (médiane, 22 mois), de boiterie, de CBPI, d'EVA, de distension articulaire et de douleur étaient significativement améliorés. L'amplitude de mouvement et la circonférence brachiale postopératoires à long terme entre les coudes affectés et non affectés n'ont pas révélé de différence significative. Les scores IEWG à long terme étaient similaires aux valeurs préopératoires dans 56 % des coudes et avaient progressé d'un grade dans 44 %. Les résultats à long terme basés sur la boiterie et les scores CBPI ont été considérés comme excellents chez 67 % des chiens, bons chez 27 % et intermédiaires chez 6 %. Le traitement arthroscopique est donc une procédure chirurgicale appropriée pour l'OCD de la trochlée humérale chez le chien et donne de bons résultats à long terme.(Traduit par les auteurs).

Simplified Minimally Invasive Surgical Approach for Prophylactic Laparoscopic Gastropexy in 21 Cases.

The objective of this study was to describe the operative technique and outcome of a simplified laparoscopic gastropexy approach in dogs. Twenty-one dogs undergoing prophylactic laparoscopic gastropexy with a simple continuous barbed suture without incising the seromuscular layer of the stomach and transversus abdominis muscle were reviewed. In 20 cases, additional procedures were performed (18 ovariectomies and 2 prescrotal castrations); 1 dog had two prior episodes of gastric dilation without volvulus and underwent gastropexy with a prophylactic intent. The gastropexy procedure had a median duration of 33 min (range 19-43 min). V-Loc 180 absorbable and the V-Loc PBT nonabsorbable suturing devices were used in 8 and 13 dogs, respectively. Minor intraoperative complications occurred in four cases: broken suture (1), needle dislodgement (2), and folded needle (1). Minor complications included self-limiting wound complications (3), abdominal discomfort (2), vomiting (1), and inappetence (2). Postoperative abdominal ultrasound performed after a median of 8 mo (6-36 mo) confirmed permanent adhesion at the gastropexy site in all dogs. One dog developed a fistula (1 yr postoperatively) and another a granuloma (3 mo postoperatively), both at the gastropexy site. Prophylactic laparoscopic gastropexy may be performed with knotless unidirectional barbed suture without creating an incision on the abdominal wall and stomach.

Characterization of and factors associated with causes of pleural effusion in cats.

OBJECTIVE To characterize and investigate potential associations between causes of pleural effusion and various clinical factors in a large cohort of affected cats. DESIGN Retrospective case series with nested cross-sectional study. ANIMALS 380 client-owned cats with a diagnosis of pleural effusion from January 1, 2009, through July 14, 2014, for which the cause of pleural effusion had been fully investigated. PROCEDURES Electronic medical records were reviewed and data collected regarding cat characteristics, clinical signs, cause of pleural effusion, treatment, and survival status at discharge from the hospital. Variables were examined for associations with causes of pleural effusion. RESULTS 87 (22.9%) cats died or were euthanized before discharge from the hospital. Congestive heart failure (CHF) was the most common cause (155 [40.8%]) of pleural effusion, followed by neoplasia (98 [25.8%]). Other causes included pyothorax, idiopathic chylothorax, trauma, feline infectious peritonitis, and nontraumatic diaphragmatic hernia. Cats with trauma or feline infectious peritonitis were significantly younger than those with CHF or neoplasia. Cats with lymphoma were significantly younger than those with carcinoma. Cats with CHF had a significantly lower rectal temperature at hospital admission (mean ± SD, 36.9 ± 1.2°C [98.4 ± 2.2°F]) than did cats with pleural effusion from other causes (37.9 ± 1.2°C [100.2 ± 2.2°F]). CONCLUSIONS AND CLINICAL RELEVANCE Cats with pleural effusion in this study had a poor prognosis; CHF and neoplasia were common causes. Age and hypothermia may be helpful to raise the index of suspicion for certain underlying causes of pleural effusion in cats.

Short- and long-term outcomes after shoulder excision arthroplasty in 7 small breed dogs.

This study reports short- and long-term clinical outcomes following excision arthroplasty in 7 small breed dogs with shoulder pathology. Lameness and pain were scored before surgery, and reassessed at short- and long-term follow-ups with measurements of range of motion (ROM), scapulo-humeral angles of extension (EA) and flexion (FA), and muscle girth (MG) of the operated and contralateral limbs. All dogs improved clinically for lameness and pain. Range of motion, EA, and FA of the operated limb were not significantly different compared with the contralateral limb at short-term follow-up, but ROM and EA were significantly decreased at long-term examination. Muscle girth was not significantly different than the contralateral limb. Radiographic re-evaluations showed bony proliferation around osteotomies without interosseous union in most dogs and all owners were satisfied with the surgery outcome. Excision arthroplasty seems to be an effective treatment for chronic shoulder pathologies in small dogs. Range of motion and EA were decreased and a mild lameness remained present at long-term follow-up.

Évolution à court et à long terme suite à une arthroplastie d'épaule chez sept chiens de petite race. Cette étude rapporte l'évolution clinique à court et long terme suite à une arthroplastie d'excision chez sept chiens de petite race avec des anomalies de l'épaule. Les degrés de boiterie et de douleur ont été évalués avant la chirurgie et réévalués à court et à long terme avec l'amplitude de mouvement (ADM), les angles d'extension (AE) et de flexion (AF) de l'épaule, et le périmètre musculaire (PM) du membre opéré et du membre controlatéral. Tous les chiens se sont améliorés cliniquement concernant la boiterie et la douleur. Il n'y avait pas de différence significative entre l'ADM, AE et AF du membre opéré par rapport au membre controlatéral à court terme, par contre l'ADM et l'AE étaient significativement réduits à long terme. Le PM n'a pas changé de façon significative comparativement au membre controlatéral. Les réévaluations radiographiques ont montré une prolifération osseuse le long des traits d'ostéotomie sans évidence d'union interosseuse sur la majorité des chiens et tous les propriétaires ont été satisfaits du résultat de la chirurgie. L'arthroplastie d'excision semble être un traitement efficace des pathologies chroniques de l'épaule chez les petits chiens. Une diminution de l'ADM et l'AE et une légère boiterie restaient présents à long terme.(Traduit par les auteurs).

Comparison between double-pigtail ureteral stents and ureteral bypass devices for treatment of ureterolithiasis in cats.

OBJECTIVE To compare the complication rates and outcomes in cats with ureteral obstruction treated by placement of double-pigtail ureteral stents or ureteral bypass (UB) devices. DESIGN Retrospective cohort study. ANIMALS Cats with unilateral or bilateral ureterolithiasis that received double-pigtail ureteral stents (30 stents in 27 cats; stent group) or UB devices (30 devices in 23 cats; UB group). PROCEDURES Medical records were reviewed to collect data on signalment, clinical signs, serum biochemical data, surgical procedure, duration of hospitalization, complications, and follow-up (≥ 6 months after placement) information. Outcomes were compared between device types. RESULTS Median durations of surgery and hospitalization were significantly longer in the stent versus UB group. Perioperative mortality rate was 18% (5/27) in the stent group and 13% (3/23) in the UB group. Median survival time was shorter in the stent versus UB group. Stent placement was associated with a greater risk of lower urinary tract-related signs, such as hematuria (52% [14/27]) and pollakiuria or stranguria (48% [13/27]). The risk of device occlusion was also greater in the stent (26% [7/27]) versus UB (4% [1/23]) group. The percentage of cats requiring additional procedures to treat complications was greater in the stent (44%; complications included uroabdomen, stent occlusion, and refractory cystitis) versus UB (9%; complications included UB occlusion and urethral obstruction) group. CONCLUSIONS AND CLINICAL RELEVANCE Although the benefits of stent placement in the treatment of ureteral obstruction in cats have been established, results suggested that cats treated with UB devices had a lower risk of complications and a longer survival time than those treated with double-pigtail ureteral stents.

High-Definition Video Telescope-Assisted Ventral Slot Decompression Surgery for Cervical Intervertebral Disc Herniation in 30 Dogs.

OBJECTIVE: To describe the use of a video telescope operating monitor (VITOM™) for ventral slot decompression and to report its clinical applications using preoperative and postoperative computed tomography (CT) myelography. STUDY DESIGN: Prospective case series. ANIMALS: Consecutive dogs presented with cervical intervertebral disc disease requiring surgical decompression (n = 30). METHODS: Demographic data, preoperative neurological status, localization and lateralization of the compression, total operative time, surgical complications, ventral slot size and orientation, hospitalization time, and postoperative outcome were recorded. Preoperative and postoperative spinal cord area at the compression site and ratios of compressed to normal spinal cord area were calculated by CT myelography. RESULTS: French Bulldogs were the most common breed of dogs (n = 15; 50%) and neck pain was the most common neurological sign (n = 18; 60%). Postoperative CT myelography confirmed that spinal cord decompression, postoperative spinal cord area, and the ratios of compressed to normal spinal cord area improved significantly compared with preoperative measurements (P = .01). Sinus bleeding occurred in 20% of dogs. The mean ratios (± SD) of ventral slot length and width compared with vertebral body length and width were 0.21 ± 0.08 and 0.31 ± 0.07, respectively. The mean postoperative hospitalization time was 3.0 ± 0.6 days and all dogs showed clinical improvement and an excellent outcome. CONCLUSION: The VITOM™ ventral slot decompression technique was fast and easy to perform. It allowed a minimally invasive approach with a small ventral slot while improving spinal cord visualization. The results of this study support the use of the VITOM™ technique in spinal veterinary surgery.

Feasibility of Stifle Medial Meniscal Release in Toy Breed Dogs with and without a Joint Distractor.

OBJECTIVE: To investigate the feasibility of medial meniscal release (MMR) during stifle arthroscopy in toy breed dogs with and without a joint distractor. STUDY DESIGN: Experimental cadaveric study. SAMPLE POPULATION: Stifles (n = 40) from 20 canine cadavers (1.8-5.1 kg). METHODS: Paired stifles were randomly assigned to the joint distractor group and the control group (n = 20 each). All stifles underwent arthroscopic transection of the cranial cruciate ligament followed by a release of the caudomedial meniscotibial ligament. After the procedures, all stifles were disarticulated. The degree of released meniscus was recorded subjectively by 5% increments. A MMR success was defined as a complete transection. The areas of femoral and tibial articular cartilage damage were calculated using india ink staining and digital imaging. The results were compared between groups and odds ratios were calculated. RESULTS: All stifle arthroscopies were successful. The success rate of MMR was significantly higher (P = .013) with a joint distractor than without a joint distractor. MMR was 7.4 times more likely to succeed with a joint distractor than without a joint distractor. The distal femoral articular cartilage was significantly more damaged (P = .011) in the stifles without a joint distractor than in the stifles with a distractor. No difference was found between the 2 groups for damage to the tibial cartilage (P = .058). CONCLUSION: Stifle arthroscopic MMR is feasible in toy breed dogs. Using a joint distractor is recommended for arthroscopic treatment based on our results because it significantly reduced the rate of incomplete release as well as iatrogenic cartilage damage.

Evaluation of a Veress needle for the fluid egress system of stifle arthroscopy in toy dog breeds.

OBJECTIVES: The aim of this study was to evaluate the use of a Veress needle as a fluid egress system for stifle arthroscopy in toy dog breeds. METHODS: Cadaveric canine stifle joints (n = 32) were prepared to induce an artificial intra-articular haemorrhagic effect, followed by stifle arthroscopy. The stifles were randomly assigned to one of three groups, and a fluid egress portal was established using a Veress needle (VN), a standard egress cannula (SE), or an intravenous catheter stylet (CS). Time to establish the egress portal, arthroscopic visibility, and egress portal performance were evaluated during the arthroscopy. After the arthroscopic examinations, iatrogenic cartilage lesions were identified and analysed using the percentage area of cartilage damage (%ACD). RESULTS: The overall arthroscopic visibility and egress portal performance were not significantly different among the groups. The egress portal establishment was faster for the VN (33 sec) and the CS (34 sec) groups than for the SE (43 sec) group (p = 0.001). On gross joint examination, no iatrogenic laceration was found in the VN group, whereas four out of 10 of the SE and two out of 10 of the CS specimens had linear cartilage excoriation on the stifle joints. The %ACD score of the VN group was lower than those of the SE group (p = 0.009) and the CS group (p = 0.001). CLINICAL SIGNIFICANCE: The Veress needle method used in this study was useful to establish a fluid egress system and limit iatrogenic cartilage excoriations. This technique could become the method of choice for stifle arthroscopy, especially in smaller dogs.

Spontaneous gastrointestinal perforation in cats: a retrospective study of 13 cases.

OBJECTIVES: The aim of this study was to describe the clinical characteristics and the frequency of malignant vs non-malignant causes for spontaneous gastrointestinal perforation in cats. METHODS: The medical records of cats diagnosed as having gastrointestinal perforation between August 2010 and July 2013 were reviewed. Diagnosis was confirmed by exploratory surgery. Patients with incomplete records, perforation due to external trauma, leakage at previous enterotomy or anastomotic sites, or foreign bodies were excluded. Each record was examined for different information pertaining to signalment, medical history, clinical and clinicopathological data, imaging findings, abdominal fluid examination, surgical findings, histopathological examination, treatment received after surgery and outcome. RESULTS: Thirteen cats were included. Five of these cats had concurrent illnesses, including viral upper respiratory tract disease, pancreatitis and chronic kidney disease. Two cats had previously received non-steroidal anti-inflammatory drugs and four had received corticosteroids. Clinical signs and clinicopathological abnormalities were not specific. Six of 13 patients were diagnosed during surgery with gastric perforations, four patients with duodenal perforations and three patients with jejunal perforations. Histopathological examination of the ulcerated wall was performed in 11/13 cats. Alimentary lymphoma was diagnosed in six cats. Non-neoplastic lesions (lymphocytic- plasmacytic inflammatory bowel disease, necrotic suppurative enteritis) were observed in the other five cats. The major limitation of the study was the small sample size. CONCLUSIONS AND RELEVANCE: Lymphoma may be a frequent cause of spontaneous perforation in cats. Therefore, histological examination of ulceration is essential in all cases. The direct and sole implication of anti-inflammatory administration in a gastrointestinal perforation is not clearly established in this study.

Short- and long-term outcomes after arthroscopic treatment of young large breed dogs with medial compartment disease of the elbow.

OBJECTIVES: To report short- and long-term outcomes after arthroscopic treatment in young large breed dogs affected by medial coronoid process disease (MCPD) and identify variables affecting outcome. STUDY DESIGN: Prospective observational case series. ANIMALS: Large breed dogs <3 years old (n = 15; 23 elbows). METHODS: MCPD was confirmed by radiography, computed tomography, and arthroscopy. Dogs were treated by arthroscopy. Variables recorded at time of treatment included radioulnar incongruity (RUI) and degree of cartilage erosion. Variables recorded before, 6 weeks, and ≥23 months after surgery included radiographic score for osteoarthritis, trochlear notch sclerosis, muscle circumference, range of motion (ROM), and the load distribution of vertical ground reaction forces between thoracic and pelvic limbs. RESULTS: A greater load distribution to the pelvic limbs was identified preoperatively in dogs with RUI than in dogs with congruent elbows. Load distribution was not significantly improved at 6 weeks compared with preoperatively. Muscle circumference and vertical impulse distributions were improved at long-term evaluation despite an increased osteoarthritis score. This improvement was more obvious in dogs with RUI or a high degree of cartilage erosion at initial presentation. CONCLUSION: Some evidence of improvement in long-term function was found in dogs with MCPD after arthroscopic treatment. RUI and cartilage erosion at the time of diagnosis were associated with more lameness preoperatively but did not affect the final gait assessment or osteoarthritis score in this small cohort.

Knot security and tensile strength of suture materials.

OBJECTIVE: To evaluate knot security and tensile failure load of suture tied in simple interrupted, beginning continuous, and ending continuous patterns for 11 suture materials commonly used in small animal surgery. STUDY DESIGN: Mechanical study. METHODS: For each of 11 suture material types, and 5 knot sizes (2, 3, 4, 5, and 6 throws) 2 surgeons each tied 6 knots (n = 12 for each knot size in 11 suture materials). Three types of patterns were evaluated: a simple interrupted square knot, a square knot beginning a simple continuous pattern, and the knot ending a simple continuous pattern. All knots were incubated in healthy canine donor plasma at 40°C for a minimum of 24 hours. Sutures were evaluated for knot security (knots untied, suture failed by breaking, suture slipped from the clamps, or suture untied before testing) and maximum load carried before knot slippage or knot failure (termed tensile failure load). RESULTS: Significant differences were found in knot security and tensile failure load among suture types. There was no significant difference between the simple interrupted knots and the knots at the beginning of a simple continuous pattern; however, both were significantly less likely to fail than the knots tied at the end of a simple continuous pattern. The number of throws per knot had a significant effect for knot security and tensile failure load. Surgeon experience had a significant effect on failure mode and tensile failure load. CONCLUSIONS: Suture type, number of throws per knot (knot size), suture pattern, and surgeon experience play an important role in knot security and should be considered when performing surgery.

Risk factors for urinary tract infection with multiple drug-resistant Escherichia coli in cats.

The emergence of multiple drug-resistant (MDR) bacteria is a growing public health problem. The objective of this retrospective study was to identify risk factors associated with MDR Escherichia coli infection of the urinary tract in cats. All cats presenting with an E coli urinary infection between March 2010 and December 2012 were included and divided into two groups: an MDR group and a non-MDR group. The effects of different variables on the occurrence of an MDR E coli infection were evaluated: age, sex, additional diseases, number of antibiotics and number of days of hospitalisation. Fifty-two cats were identified (10 MDR and 42 non-MDR). The number of antibiotic groups used within the last 3 months was associated with an increased risk of MDR E coli urinary infection (P = 0.007). The association of the number of days of hospitalisation within the last 3 months and the increased risk of MDR E coli urinary infection did not reach significance (P = 0.090). This study provides evidence that systematic urinary culture with antibiotic sensitivity testing should be recommended when treating urinary tract infections if antibiotics have been prescribed within the past 3 months. Moreover, the selection of MDR bacteria through antibiotic use should be considered as a potential risk associated with treatment.

Effect of using triclosan-impregnated suture for incisional closure on surgical site infection and inflammation following tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To compare surgical site infection and inflammation rates between the use of nonimpregnated (polydioxanone and poliglecaprone 25) versus triclosan-impregnated (polydioxanone and poliglecaprone 25) suture for incisional closure in dogs undergoing a standardized orthopedic procedure (tibial plateau leveling osteotomy [TPLO]). DESIGN: Retrospective cohort study. ANIMALS: 283 dogs that underwent TPLO between November 2005 and December 2009. PROCEDURES: Medical records were reviewed for age; body weight; body condition score; use of propofol; perioperative and postoperative administration of antimicrobials; presence of a preoperative infection; use of a jig; technique of joint exploration; type of suture material (triclosan impregnated vs nonimpregnated) used to close the pes anserinus, subcutaneous layer, and subcuticular layer; use of staples or suture to close the skin; and surgery and anesthesia durations. The outcome variables were surgical site inflammation and infection. RESULTS: Rates of infection and inflammation did not differ between surgeries for which triclosan-impregnated suture was used (n = 159 [8.8%, and 18.8%, respectively]) and those for which nonimpregnated suture was used (112 [10.7% and 15.2%, respectively]). The use of staples, compared with suture, to close the skin significantly decreased the inflammation rate. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with in vitro conditions, in vivo conditions (where the environment is not controlled and triclosan may elute more quickly from the suture) may decrease the antibacterial effectiveness of triclosan-impregnated suture. On the basis of our findings, triclosan-impregnated sutures did not seem to provide an additional benefit for clinical use and cannot be strongly recommended for elective orthopedic procedures in veterinary medicine.

Septic peritonitis: treatment and prognosis.

Septic peritonitis is an inflammatory condition of the peritoneum that has a wide variety of clinical courses. The etiology and pathophysiology of this condition and its diagnosis in small animals are reviewed in a companion article. This article addresses the treatment of septic peritonitis and prognosis in small animals.

A comparative study of seeding techniques and three-dimensional matrices for mesenchymal cell attachment.

Mesenchymal stem cells (MSCs) offer significant potential as a cell source in tissue-engineering applications because of their multipotent ability. The objective of this study was to evaluate the behaviour of MSCs during the seeding phase, using four different seeding techniques (spinner flask, custom vacuum system combined with a perfused bioreactor or with an orbital shaker, and orbital shaker) with four different scaffold materials [polyglycolic acid, poly(lactic acid), calcium phosphate and chitosan-hyaluronic acid]. Scaffolds were selected for their structural and/or chemical similarity with bone or cartilage, and characterized via scanning electron microscopy (SEM) and measurement of fluid retention. Cell attachment was compared between seeding techniques and scaffolds via cell-binding kinetics, cell viability and DNA quantification. SEM was used to evaluate cell distribution throughout the constructs. We discovered from cell suspension kinetics and DNA data that the type of loading (i.e. direct or indirect) mainly influences the delivery of cells to their respective scaffolds, and that dynamic seeding in a spinner flask tended to improve the cellularity of polymer constructs, especially mesh. Regardless of the seeding method, bone marrow-derived MSCs displayed a superior affinity for calcium phosphate scaffolds, which may be related to their hydrophobicity. MSCs tended to aggregate into flat sheets, occluding the external pores of matrices and affecting cell distribution, regardless of seeding technique or scaffold. Taken together, these results provide insight into the design of future experiments using MSCs to engineer functional tissue.

The effect of type II collagen coating of chitosan fibrous scaffolds on mesenchymal stem cell adhesion and chondrogenesis.

The biocompatibility of chitosan and its similarity to glycosaminoglycans (GAG) make it attractive for cartilage tissue engineering. We have previously reported improved chondrogenesis but limited cell adhesion on chitosan scaffolds. Our objectives were to produce chitosan scaffolds coated with different densities of type II collagen and to evaluate the effect of this coating on mesenchymal stem cell (MSC) adhesion and chondrogenesis. Chitosan fibrous scaffolds were obtained by a wet spinning method and coated with type II collagen at two different densities. A polyglycolic acid mesh served as a reference group. The scaffolds were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and type II collagen content. Constructs were analyzed after MSCs seeding via live/dead assay, weight and DNA evaluations, SEM, and TEM. Constructs were cultured in chondrogenic medium for 21 days prior to quantitative analysis (weight, DNA, and GAG), SEM, TEM, histology, immunohistochemistry, and quantitative real time polymerase chain reaction. The cell attachment and distribution after seeding correlated with the density of type II collagen. The cell number, the matrix production, and the expression of genes specific for chondrogenesis were improved after culture in collagen coated chitosan constructs. These findings encourage the use of type II collagen for coating chitosan scaffolds to improve MSCs adhesion and chondrogenesis, and confirm the importance of biomimetic scaffolds for tissue engineering.

Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds.

The biocompatibility and biomimetic properties of chitosan make it attractive for tissue engineering but its use is limited by its cell adhesion properties. Our objectives were to produce and characterize chitosan and reacetylated-chitosan fibrous scaffolds coated with type II collagen and to evaluate the effect of these chemical modifications on mesenchymal stem cell (MSC) adhesion. Chitosan and reacetylated-chitosan scaffolds obtained by a wet spinning method were coated with type II collagen. Scaffolds were characterized prior to seeding with MSCs. The constructs were analyzed for cell binding kinetics, numbers, distribution and viability. Cell attachment and distribution were improved on chitosan coated with type II collagen. MSCs adhered less to reacetylated-chitosan and collagen coating did not improve MSCs attachment on those scaffolds. These findings are promising and encourage the evaluation of the differentiation of MSCs in collagen-coated chitosan scaffolds. However, the decreased cell adhesion on reacetylated chitosan scaffold seems difficult to overcome and will limit its use for tissue engineering.

Evaluation of intra- and interobserver variability and repeatability of tibial plateau angle measurements with digital radiography using a novel digital radiographic program.

OBJECTIVE: To compare the intra- and interobserver variability occurring when observers with differing experience levels measure tibial plateau angles (TPAs) with a novel digital radiographic projection program (tibial plateau leveling osteotomy [TPLO] planning program), the Kodak Picture Archiving and Communications System (PACS), and standard sized printed films (SF). STUDY DESIGN: Cross-sectional study. SAMPLE POPULATION: Dogs (n=36) with cranial cruciate ligament (CCL) rupture that had a TPLO. METHODS: Six observers, divided into 3 equal groups based on experience level, measured TPA on 36 digitally captured radiographic images of tibiae of dogs clinically affected with CCL rupture. Each observer used 3 methods of measuring TPA and repeated the measurements 3 times with each method. The intra- and interobserver variability was compared using the coefficient of variation. RESULTS: Averaged over all replications and images, there was no significant difference (P>.05) in the average variability occurring with each method for all but 1 observer. There was no effect of experience level on measurement variability; however, interobserver variability was significantly less with measurements made with the PACS and TPLO planning program compared with measurements made from SF (P<.05). CONCLUSIONS: Repeated measurements of TPA made using digital images and computer-based measurement programs were significantly less variable between observers than those made from images printed on standard radiographic films. CLINICAL RELEVANCE: Digital radiography and computer-based measurement programs are effective for determining the TPA, allowing less variability in measurements compared with SF. The ability to manipulate the image may allow better identification of anatomic landmarks.

Effect of chitosan scaffold microstructure on mesenchymal stem cell chondrogenesis.

Although numerous biomaterials have been investigated as scaffolds for cartilage tissue engineering, the effect of their microstructure on final construct characteristics remains unclear. The biocompatibility of chitosan and its similarity with glycosaminoglycans make it attractive as a scaffold for cartilage engineering. Our objective was to evaluate the effect of chitosan scaffold structure on mesenchymal stem cell proliferation and chondrogenesis. Chitosan fibrous scaffolds and chitosan sponges were seeded with mesenchymal stem cells in a chondrogenic medium. Constructs were analyzed 72 h after seeding via scanning electron microscopy (SEM), weight measurements and DNA quantification. Constructs were cultured for 10 or 21 days prior to confocal microscopy, SEM, histology, quantitative analysis (weight, DNA and glycosaminoglycan (GAG)), and quantitative real-time polymerase chain reaction. Mesenchymal stem cells maintained a viability above 90% on all chitosan scaffolds. The cell numbers in the constructs were similar at 72 h, 10 days and 21 days. However, matrix production was improved in chitosan fibrous constructs based on the GAG quantification and collagen II mRNA expression. Chondrogenesis on chitosan scaffolds is superior on microfibers compared to macroporous sponges.