Trained to cut? A literature review of veterinary surgical resident training.

A surgical residency trains veterinary graduates to a higher level of expertise in surgical procedures than is possible during veterinary school and prepares a resident to pursue board certification in surgery. The education of veterinary surgical residents has changed minimally since its inception in the twentieth century, and there are insufficient studies to determine if residency programs are producing surgeons with competence in each of the necessary procedural categories. The aims of this review were to report the current theory and methods used to provide surgical education to residents, to discuss the training most likely to create a competent, board-certified surgeon and to review assessment methods used during training. Several literature searches using broad terms such as "veterinary surgery residency," "veterinary surgery resident," and "veterinary surgical training" were performed using PubMed, CAB abstracts, and Google Scholar. Literature pertinent to theory, methods, training, and assessment of veterinary surgical residents was included. The reviewed literature demonstrated the need for research-based learning curves for specific procedures. Simulation training is known to facilitate deliberate practice and should be leveraged where possible to reach competency. The creation of validated assessment methods should be pursued as it enables assessment of competency instead of inferring its development from case logs. Understanding and supporting learner cognition and providing sufficient feedback remain important issues in the field. Surgical educators are urged to continue to search for innovative and evidence-based ways to train competent surgical residents.

Simulating Ovariohysterectomy: What Type of Practice Promotes Short- and Long-Term Skills Retention?

Simulation-based surgical training allows students to learn skills through deliberate practice without the patient risk and stress of operating on a live animal. This study sought to determine the ideal distribution of training sessions to improve short- and long-term retention of the skills necessary to perform a simulated ovariohysterectomy (OVH). Fourth-semester students (n = 102) were enrolled. Students in the weekly instruction group (n = 57) completed 10 hours of training on the OVH simulator, with sessions held at approximately weekly intervals. Students in the monthly instruction group (n = 45) completed the same training with approximately monthly sessions. All students were assessed 1 week (short-term retention test) and 5 months following the last training session (long-term retention test). Students in the weekly instruction group scored higher on their short-term assessment than students in the monthly instruction group (p < .001). However, students' scores in the weekly instruction group underwent a significant decrease between their short- and long-term assessments (p < .001), while the monthly group did not experience a decrease in scores (p < .001). There was no difference in long-term assessment scores between weekly and monthly instruction groups. These findings suggest that if educators are seeking maximal performance at a single time point, scheduling instructional sessions on a weekly basis prior to that time would be superior to monthly sessions, but if educators are concerned with long-term retention of skills, scheduling sessions either on a weekly or monthly basis would accomplish that purpose.

Retention of basic surgical skills in veterinary students.

OBJECTIVE: To quantify veterinary students' retention of surgical skills after a 5-month period without practice. STUDY DESIGN: Prospective longitudinal descriptive study. SAMPLE POPULATION: Convenience sample of second year veterinary students (n = 57). METHODS: Students practiced ovariohysterectomy (OVH) on a model during 4 clinical skills laboratories during spring 2021. Students were assessed performing OVH on their model using a validated 22-item rubric. Students not meeting expectations repeated their assessment 2 weeks later. All students had a 5-month period, including summer break, without skills practice. Students were again assessed performing OVH on their model in the fall. Students' rubric scores and pass rates were compared before and after summer break. RESULTS: Students scored lower on their retention test in fall (median = 43) than at the spring assessment (median = 56, P < .001). No difference was detected between lower and higher performing students. Five students (9%) did not meet expectations on their first assessment; more students (17/57, 30%) failed to meet expectations on their retention test (P = .004). CONCLUSION: Students experienced a decay in the surgical skills required to perform OVH after a 5-month period without practice, regardless of the quality of their initial performance. CLINICAL SIGNIFICANCE: Veterinary educators should emphasize the importance of continual practice to maintain skills and should consider assisting students in regaining skills during review sessions on models to improve surgical skill retention after a prolonged break.

Validation of a Rubric Used for Skills-Based Assessment of Veterinary Students Performing Simulated Ovariohysterectomy on a Model.

Surgical skills are an important competency for new graduates. Simulators offer a means to train and assess veterinary students prior to their first surgical performance. A simulated ovariohysterectomy (OVH) rubric's validity was evaluated using a framework of content evidence, internal structure evidence, and evidence of relationship with other variables, specifically subsequent live surgical performance. Clinically experienced veterinarians (n = 13) evaluated the utility of each rubric item to collect evidence; each item's content validity index was calculated to determine its inclusion in the final rubric. After skills training, veterinary students (n = 57) were assessed using the OVH model rubric in March and August. Internal structure evidence was collected by video-recording 14 students' mock surgeries, each assessed by all five raters to calculate inter-rater reliability. Relationship with other variables evidence was collected by assessing 22 students performing their first live canine OVH in November. Experienced veterinarians included 22 items in the final rubric. The rubric generated scores with good to excellent internal consistency; inter-rater reliability was fair. Students' performance on the March model assessment was moderately correlated with their live surgical performance (ρ = 0.43) and moderately negatively correlated with their live surgical time (ρ = -0.42). Students' performance on the August model assessment, after a summer without surgical skills practice, was weakly correlated with their live surgical performance (ρ = 0.17). These data support validation of the simulated OVH rubric. The continued development of validated assessment instruments is critical as veterinary medicine seeks to become competency based.

What's the evidence? A review of current instruction and assessment in veterinary surgical education.

Veterinary surgical education is improved by studying the relevant literature. The aim of this literature review was to report the theory and methods used to provide surgical education to veterinary students; to discuss the training most likely to create a competent general practitioner; and to review assessment methods for simulated and live surgeries. The literature reviewed demonstrates that new graduates are expected to perform small animal sterilization, dental extraction, onychectomy, abscess treatment, aural hematoma repair, and mass removal with little or no supervision. Students require repetitive practice to reach competence; some practice can take place in a clinical skills laboratory on models or cadavers. When training novices, distributing practice over a longer time improves retention, but months without practice causes skills to decay. Suturing skills may be taught on models at a ratio of 1 instructor per 10 students. Veterinary students require 6-10 repetitions of each small animal sterilization surgery to reach competence; however, learning curves for other surgeries have not been established. Assessment of surgical skills has been undertaken using objective structured clinical examinations (OSCEs) and observed model and live surgeries. Additional validated rubrics are needed in the field. Surgical educators are urged to continue to search for innovative ways to foster deliberate practice, assess skill, and provide feedback for students.

If you build it, they will learn: A review of models in veterinary surgical education.

Surgical skills are learned through deliberate practice, and veterinary educators are increasingly turning to models for teaching and assessing surgical skills. This review article sought to compile and review the literature specific to veterinary surgical skills models, and to discuss the themes of fidelity, educational outcomes, and validity evidence. Several literature searches using broad terms such as "veterinary surgery model," "veterinary surgical model," and "veterinary surgical simulator" were performed using PubMed, CAB abstracts, and Google scholar. All articles describing a model created and utilized for veterinary surgical training were included. Other review articles were used as a source for additional models. Commercially available models were found using review articles, internet browser searches, and communication with veterinary clinical skills educators. There has been an explosion of growth in the variety of small animal surgical task trainers published in the last several decades. These models teach orthopedic surgery, ligation and suturing, open celiotomy and abdominal surgery, sterilization surgeries, and minimally invasive surgeries. Some models were published with accompanying rubrics for learner assessment; these rubrics have been noted where present. Research in veterinary surgical models is expanding and becoming an area of focus for academic institutions. However, there is room for growth in the collection of validity evidence and in development of models for teaching large animal surgery, training surgical residents, and providing continuing education to practitioners. This review can assist with evaluation of current surgical models and trends, and provide a platform for additional studies and development of best practices.

The impact of gel fingernail polish application on the reduction of bacterial viability following a surgical hand scrub.

OBJECTIVE: To determine the effect of gel nail polish application on the reduction of bacterial viability immediately after a surgical hand scrub. STUDY DESIGN: Randomized controlled trial. SAMPLE POPULATION: Ten fingernails each from 40 female health care professionals and students. METHODS: Participants' fingernails were randomized to receive no polish or gel nail polish during a manicure from a licensed manicurist. One day and 14 days after manicure, participants' fingernails were sampled before and after a surgical hand scrub with chlorhexidine gluconate. The samples for each fingernail were serially diluted, plated on a Trypsin sheep blood agar and MacConkey's agar plate, and incubated for 36 h. For each plate, bacterial colony forming units (CFU)/ml were determined. Mixed linear models were used to assess factors associated with the logarithmic reduction of viable bacterial counts from pre- to post-surgical scrub. RESULTS: In the final model, no association was detected between gel nail polish and reduction of viable bacterial count (p = .09). On Day 14, among longer nail lengths (2 to <3-mm and ≥3-mm), surgical scrubs resulted in greater reduction in bacterial counts in left-handed than right-handed participants (p < .01). Increasing nail length was correlated with increased CFU/ml post-scrubbing (p < .001). CONCLUSION: Application of gel nail polish did not seem to affect the ability of surgical scrub to reduce bacterial viability 1 and 14 days after a manicure. CLINICAL IMPACT: This study does not provide evidence to prevent application of gel nail polish on short fingernails in surgeons prior to surgical hand scrub with chlorhexidine gluconate.

Influence of instructor-to-student ratio for teaching suturing skills with models.

OBJECTIVE: To evaluate the influence of instructor to student ratio on the effectiveness and efficiency of teaching suturing skills to veterinary students. STUDY DESIGN: Prospective randomized study. SAMPLE POPULATION: Second-year veterinary students (N = 121). METHODS: Students were randomly divided into three groups to participate in four 2-hour skills laboratory sessions in which suturing of the subcutaneous tissue was taught by using a simple continuous pattern, suturing of the skin was taught by using continuous patterns, suturing of the skin was taught by using interrupted patterns, and suturing of hollow organs was taught by using inverting patterns. For each laboratory, the groups were taught by using instructor-to-student ratios of 1:6, 1:8, and 1:10 on a rotating basis. Students were surveyed at the end of each laboratory, and underwent individual performance assessments at the end of each laboratory session and again at the end of the semester in an objective structured clinical examination (OSCE). RESULTS: For each of the four in-laboratory assessments and the OSCE, no difference in performance was detected between groups. When they were surveyed, students in all groups reported that there was an adequate number of instructors in the laboratory and that they received help in a timely fashion when help was requested (median for all groups = agree). CONCLUSION: For students with prior surgical skills education and with the use of prelaboratory instructional videos, teaching at the 1:10 instructor-to-student ratio was efficient and effective. CLINICAL SIGNIFICANCE: Good educational outcomes may be reached with a 1:10 instructor-to-student ratio or, potentially, fewer instructors, depending on the educational aids present in the laboratory and students' prior level of experience.

The Impact of Extracurricular Surgical Experience on Veterinary Students' Performance of Canine Ovariohysterectomy and Orchidectomy in a Clinical Skills Curriculum.

Veterinary students may pursue extracurricular surgical experiences before performing ovariohysterectomy or orchidectomy in their veterinary curriculum. We sought to evaluate the impact of these experiences on student confidence and subsequent surgical performance during students' first canine ovariohysterectomy or orchidectomy during their veterinary school curriculum. We enrolled 69 third-year veterinary students to complete pre- and post-operative surveys reporting their confidence to perform surgery and self-assessing their performance. Students had all completed five semesters of surgical skills training on models and cadavers but varied in their participation in extracurricular surgical experiences. A subset of students (n = 27) were digitally recorded while performing ovariohysterectomy (16) or orchidectomy (11). Digital recordings were scored by a blinded rater using task-specific rubrics and a global rating scale, and time to perform the procedure was recorded. The number of extracurricular surgeries students had performed was positively correlated with their confidence to perform orchidectomy (r = .78) but not ovariohysterectomy (r = -.17). There was no correlation between extracurricular surgeries performed and subsequent rubric scores or surgical times for the first ovariohysterectomy (r = -.01 and r = -.14, respectively) or orchidectomy (r = .09 and r = -.18, respectively) performed as part of their veterinary curriculum. Our results suggest that extracurricular surgical experiences may not impart a long-term improvement on performance scores or surgical time during students' first surgery of their veterinary curriculum. Additional research is necessary to clarify how model training and extracurricular surgical experiences on live animals interact to affect students' subsequent surgical performance.

Depletion of pulmonary intravascular macrophages rescues inflammation-induced delayed neutrophil apoptosis in horses.

The objective of this study was to determine the effect of pulmonary intravascular macrophage depletion on systemic inflammation and ex vivo neutrophil apoptosis using an experimental model of intestinal ischemia and reperfusion injury in horses. Neutrophils were isolated before and after surgery from horses that were randomized to three treatment groups, namely, sham celiotomy (CEL, n = 4), intestinal ischemia and reperfusion (IR, n = 6), and intestinal ischemia and reperfusion with gadolinium chloride treatment to deplete pulmonary intravascular macrophages (PIMs, IRGC, n = 6). Neutrophil apoptosis was assessed with Annexin V and propidium iodide staining quantified with flow cytometry and caspase-3, caspase-8, and caspase-9 activities in neutrophil lysates. All horses experienced a systemic inflammatory response following surgery. Following surgery, ex vivo neutrophil apoptosis was significantly delayed after 12 or 24 h in culture, except in IRGC horses (12 h: CEL: P = 0.03, IR: P = 0.05, IRGC: P = 0.2; 24 h: CEL: P = 0.001, IR: P = 0.004, IRGC: P = 0.3). Caspase-3, caspase-8, and caspase-9 activities were significantly reduced in neutrophils isolated after surgery and cultured for 12 h in IR horses, but not in IRGC horses (IR caspase-3: P = 0.002, IR caspase-8: P = 0.002, IR caspase-9: P = 0.04). Serum TNF-α concentration was increased in IRGC horses for 6-18 h following jejunal ischemia. Following surgery, ex vivo equine neutrophil apoptosis was delayed via downregulation of caspase activity, which was ameliorated by PIM depletion potentially via upregulation of TNF-α.

Does virtual reality training improve veterinary students' first canine surgical performance?

BACKGROUND: Virtual reality (VR) applications are effective tools in many educational disciplines. A minimally interactive VR application allowing stereoscopic viewing of surgical videos has been developed to aid veterinary students learning to perform surgery. We sought to describe how students used the VR application while preparing to perform their first canine sterilisation surgery and compare surgical performance of students who prepared using traditional methods with students who also used VR. METHODS: Third-year veterinary students (n=44) were randomised into control and VR groups in a parallel superiority randomised controlled trial. All were given lectures, videos and skills practice on models. VR group students were also given a VR application and headset to view stereoscopic surgical videos. Blinded raters scored a subset of students (n=19) as they performed their first canine ovariohysterectomy. RESULTS AND CONCLUSIONS: Groups spent similar time preparing to perform surgery, potentially because of the rigour of students' non-surgical course load. When VR training was added to an already comprehensive surgical skills curriculum, students watched VR videos for a median of 90 min. Groups did not differ in surgical performance scores or time. A larger study of the VR application with prescribed use guidelines would be a helpful subsequent study.

Comparison of 2 canine celiotomy closure models for training novice veterinary students.

OBJECTIVE: To compare a low-fidelity foam and fabric (FF) model to a high fidelity silicone (SI) model for teaching canine celiotomy closure. STUDY DESIGN: Prospective blinded comparison of learning outcomes. SAMPLE POPULATION: Second-year veterinary students who had never performed surgery as a primary surgeon (n = 46) and veterinarians experienced in performing canine celiotomy (n = 10). METHODS: Veterinary students performed a digitally recorded celiotomy closure on a canine cadaver before and after participation in 4 facilitated laboratory training sessions on their randomly assigned model. Recordings were scored by masked, trained educators with an 8-item task-specific rubric. Students completed surveys evaluating the models. Experienced veterinarians tested the models and provided feedback on their features. RESULTS: Completed pretest and posttest recordings were available for 38 of 46 students. Students' performance improved regardless of the model used to practice (P = .04). The magnitude of improvement did not differ between the 2 groups (P = .10). All students (n = 46) described their models favorably. Ninety percent of veterinarians thought both models were helpful for training students and gave similar ratings on all measures except for realism, which was rated higher for the SI model's skin (median, agree) compared with the FF model (median, neutral, P = .02). CONCLUSION: Model-based training was effective at improving students' surgical skills. Less experienced learners achieved similar skill gains after practicing with FF or SI models. CLINICAL SIGNIFICANCE: The acquisition of surgical skills required to perform celiotomy closure in companion animals occurs similarly well on models made of foam and fabric or of silicone, providing flexibility in model selection.

Effects of Continuing Education Incentives on Clinical Instructors.

PURPOSE: To research whether the ability to earn continuing education (CE) credit for time spent teaching motivates radiologic science professionals to teach students in clinic and to assess whether sonographers, who earn CE credit for time teaching, have more positive attitudes toward teaching than those in modalities who do not earn CE credit for time spent teaching. METHODS: Researchers developed a 2-track digital survey and delivered it electronically and on paper to clinical instructors working at hospitals affiliated with Department of Medical Imaging and Radiation Sciences programs at the University of Oklahoma Health Sciences Center. Responses were collected for 2 weeks and then compared quantitatively using chi-square tests and logistic regression models. Qualitative results were examined for themes, and proportions among themes were reported. RESULTS: A total of 239 people responded, with 166 responses coming from individuals working in radiography, radiation therapy, nuclear medicine, and medical dosimetry, and 73 responses from sonography. Receiving CE credit did not result in a difference in teaching attitudes (x2 5 0.0004, DF 5 1, P 5 .985). However, the non-CE credit-earning population showed a 12% increase in positive attitudes if allowed to earn CE credit in the future (95% CI; 0.08, 0.17). DISCUSSION: Student learning and performance in clinic directly are related to experiencing a positive learning environment. Factors other than CE credit appear to motivate instructors to teach students. Although the results of this study did not support the hypotheses, this study furthers the need to discuss whether offering CE credit for clinic instruction is something the profession should consider. CONCLUSION: Clinical instructors who are willing to teach are the most desirable to students. Further evaluation of CE credit as an extrinsic motivating factor for clinical instructorship is important for providing the best positive learning environment for students.

Evaluation of a method to assess digitally recorded surgical skills of novice veterinary students.

OBJECTIVE: To evaluate a method to assess surgical skills of veterinary students that is based on digital recording of their performance during closure of a celiotomy in canine cadavers. SAMPLE POPULATION: Second year veterinary students without prior experience with live animal or simulated surgical procedure (n = 19) METHODS: Each student completed a 3-layer closure of a celiotomy on a canine cadaver. Each procedure was digitally recorded with a single small wide-angle camera mounted to the overhead surgical light. The performance was scored by 2 of 5 trained raters who were unaware of the identity of the students. Scores were based on an 8-item rubric that was created to evaluate surgical skills that are required to close a celiotomy. The reliability of scores was tested with Cronbach's α, intraclass correlation, and a generalizability study. RESULTS: The internal consistency of the grading rubric, as measured by α, was .76. Interrater reliability, as measured by intraclass correlation, was 0.64. The generalizability coefficient was 0.56. CONCLUSION: Reliability measures of 0.60 and above have been suggested as adequate to assess low-stakes skills. The task-specific grading rubric used in this study to evaluate veterinary surgical skills captured by a single wide-angle camera mounted to an overhead surgical light produced scores with acceptable internal consistency, substantial interrater reliability, and marginal generalizability. IMPACT: Evaluation of veterinary students' surgical skills by using digital recordings with a validated rubric improves flexibility when designing accurate assessments.

Occurrence of Incisional Complications After Closure of Equine Celiotomies With USP 7 Polydioxanone.

OBJECTIVES: To report the occurrence of, and risk factors associated with, incisional complications of equine ventral median celiotomies closed with USP 7 polydioxanone (7PD). STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Horses (n = 73; 75 celiotomies). METHODS: Medical records (2000-2010) were retrieved and reviewed for horses that had a ventral celiotomy closed with 7PD and survived ≥14 days. Follow-up (>1 year) was obtained from the medical record, owner, or referring veterinarian. Independent variables were selected based on risk factors identified in previous studies, perceived clinical relevance, and if there were adequate data recorded in the medical record. Statistical analysis, including multivariable logistic regression with a forward-building model process, was performed to evaluate variables associated with incisional complications. RESULTS: One or more incisional complication(s) occurred in 19 celiotomies (25.3%) during hospitalization or after discharge including: drainage (25.3%), infection (12.0%), and partial dehiscence (5.3%). Two of 63 horses (3.2%) available for follow-up developed an incisional hernia. Variables associated with incisional complications after multivariate analysis included: number of days hospitalized, surgery time, postoperative colic, and postoperative fever. CONCLUSION: Overall occurrence of incisional herniation after closure of ventral celiotomies with 7PD was low.

The immune response to anesthesia: part 2 sedatives, opioids, and injectable anesthetic agents.

OBJECTIVE: To review the immune response to injectable anesthetics and sedatives and to compare the immunomodulatory properties between inhalation and injectable anesthetic protocols. STUDY DESIGN: Review. METHODS AND DATABASES: Multiple literature searches were performed using PubMed and Google Scholar from March 2012 through November 2013. Relevant anesthetic and immune terms were used to search databases without year published or species constraints. The online database for Veterinary Anaesthesia and Analgesia and the Journal of Veterinary Emergency and Critical Care were searched by issue starting in 2000 for relevant articles. CONCLUSION: Sedatives, injectable anesthetics, opioids, and local anesthetics have immunomodulatory effects that may have positive or negative consequences on disease processes such as endotoxemia, generalized sepsis, tumor growth and metastasis, and ischemia-reperfusion injury. Therefore, anesthetists should consider the immunomodulatory effects of anesthetic drugs when designing anesthetic protocols for their patients.

Ex vivo comparison of the biomechanical properties of hand-sewn and stapled jejunoileal anastomoses in horses.

OBJECTIVE: To compare bursting strength, construction time, and anastomotic dimensions of 4 jejunoileal anastomotic techniques. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Adult horses (n = 12). METHODS: Jejunoileal anastomoses were constructed from harvested ileal and distal jejunal segments using a single-layer Lembert technique (1HS), double-layer simple continuous/Cushing technique (2HS), stapled side-to-side technique (SS), or stapled functional end-to-end technique (FEE). Anastomotic construction time was recorded. Bursting pressures (BP), bursting wall tension (BWT), percentage of mean anastomotic luminal diameter reduction, percentage of luminal diameter reduction relative to adjacent ileal and jejunal diameters and stomal length, were calculated. RESULTS: FEE had the shortest construction time. BP of 1HS and 2HS was significantly higher than FEE and SS (P < .001), which were not different from each other (P = .67). There were no significant differences in BP (P = .25) and BWT (P = .21) between 1HS and 2HS. Mean luminal diameter reduction was less for 1HS (25.1%) than for 2HS (34.8%), however, not statistically different (P = .12). Luminal diameter reduction relative to ileal diameter was significantly less for 1HS (15.2%) than for 2HS (28.47%; P = .012). Luminal diameter reduction relative to jejunal diameter was less for 1HS (32.4%) than 2HS (44.6%) but not statistically different; P = .07). Stomal length was significantly larger for SS (9.93 cm) than FEE (7.32 cm; P = .0002). CONCLUSION: 1HS and 2HS jejunoileal anastomosis are equal in strength; however, 1HS results in less relative luminal diameter reduction. SS and FEE have comparable strength but fail at significantly lower BPs than hand-sewn jejunoileal anastomoses.

Ex vivo evaluation of 7 polydioxanone for closure of equine ventral midline celiotomies.

The objective of this study was to compare the bursting strength (BS) and mode of failure (MF) of ventral midline (VM) celiotomies closed with USP 7 polydioxanone (7PD) in 1 or 2 simple continuous sections. A bursting strength model, consisting of inserting and inflating a 200-L polyurethane bladder through a 25-cm VM celiotomy, was used on 15 fresh equine cadavers. Celiotomies were closed using 7PD in 2 separate sections (4 knots), 2 continuous sections (3 knots), or a single section (2 knots) using a simple continuous pattern. The horses' signalment, body weight, number of total knots, MF, and BS were recorded and analyzed statistically for interactions. No difference was found between the BS of VM celiotomies closure types (P = 0.4). All celiotomy/ suture constructs failed at the abdominal wall. The celiotomy closure types evaluated in this study provided a secure method of closure in VM celiotomies in vivo.

L'objectif de la présente étude était de comparer la force d'éclatement (BS) et le mode d'échec (MF) de laparotomies par la ligne ventrale médiale (VM) refermées avec du 7 polydioxanone USP (7PD) en une ou 2 sections continues. Un modèle de force d'éclatement, consistant en l'insertion et le gonflement une vessie de 200 L en polyuréthane via une laparotomie de 25 cm fut utilisé sur 15 cadavres frais de cheval. Les laparotomies étaient refermées en utilisant le 7PD en deux sections séparées (4 nœuds), 2 sections continues (3 nœuds), ou une section simple (2 nœuds) au moyen d'un patron simple continu. L'historique des chevaux, leur poids corporel, le nombre total de nœuds, MF, et BS ont été enregistrés et analysés statistiquement pour les interactions. Aucune différence ne fut trouvée entre les BS et les types de fermetures de VM des laparotomies (P = 0,4). Toutes les laparotomies/modes de suture ont lâché au niveau de la paroi abdominale. Les types de fermeture des laparotomies évalués dans ce projet ont fourni une méthode sécuritaire de fermeture par la VM de laparotomies in vivo.(Traduit par Docteur Serge Messier).

On the evolutionary and biogeographic history of Saxifraga sect. Trachyphyllum (Gaud.) Koch (Saxifragaceae Juss.).

Arctic-alpine plants in the genus Saxifraga L. (Saxifragaceae Juss.) provide an excellent system for investigating the process of diversification in northern regions. Yet, sect. Trachyphyllum (Gaud.) Koch, which is comprised of about 8 to 26 species, has still not been explored by molecular systematists even though taxonomists concur that the section needs to be thoroughly re-examined. Our goals were to use chloroplast trnL-F and nuclear ITS DNA sequence data to circumscribe the section phylogenetically, test models of geographically-based population divergence, and assess the utility of morphological characters in estimating evolutionary relationships. To do so, we sequenced both genetic markers for 19 taxa within the section. The phylogenetic inferences of sect. Trachyphyllum using maximum likelihood and Bayesian analyses showed that the section is polyphyletic, with S. aspera L. and S bryoides L. falling outside the main clade. In addition, the analyses supported several taxonomic re-classifications to prior names. We used two approaches to test biogeographic hypotheses: i) a coalescent approach in Mesquite to test the fit of our reconstructed gene trees to geographically-based models of population divergence and ii) a maximum likelihood inference in Lagrange. These tests uncovered strong support for an origin of the clade in the Southern Rocky Mountains of North America followed by dispersal and divergence episodes across refugia. Finally we adopted a stochastic character mapping approach in SIMMAP to investigate the utility of morphological characters in estimating evolutionary relationships among taxa. We found that few morphological characters were phylogenetically informative and many were misleading. Our molecular analyses provide a foundation for the diversity and evolutionary relationships within sect. Trachyphyllum and hypotheses for better understanding the patterns and processes of divergence in this section, other saxifrages, and plants inhabiting the North Pacific Rim.

Ex vivo comparison of 7 polydioxanone, 2 polyglactin 910 for closure of ventral median celiotomy in horses.

OBJECTIVE: To compare bursting strength and failure mode between ventral median celiotomies closed with USP 7 braided polydioxanone (7PD) or USP 2 polyglactin 910 (2PG). STUDY DESIGN: Ex vivo experimental. ANIMALS: Equine cadavers (n = 10). METHODS: A 25 cm ventral median celiotomy was created in fresh equine cadavers. A 200 L polyurethane bladder was inserted into the abdomen. Celiotomies were closed in a simple continuous pattern with 2 sections of 7PD or 2PG. The bladder was inflated with compressed air until construct failure. The horses' signalment, body weight, suture type, failure mode (suture or abdominal wall), and bursting strength (mmHg) were recorded. Interactions between independent and dependent variables were assessed with statistical tests including linear regression. RESULTS: Failure mode was significantly different by suture type (P = .01). Four of 5 celiotomies closed with 2PG failed at the suture; whereas, 0 celiotomies closed with 7PD failed at the suture. In celiotomies closed with 7PD, increasing age was highly and negatively correlated with bursting strength (r = -0.99). When the effect of age was controlled, 7PD had a significantly higher bursting strength than 2PG (P = .024). CONCLUSION: 7PD has a higher bursting strength compared with 2PG. Suture failure was the main failure mode for 2PG; whereas, all celiotomies closed with 7PD failed at the abdominal wall.