Ex vivo comparison of pin placement with patient-specific drill guides or freehand technique in canine cadaveric spines.

OBJECTIVE: To compare vertebral implant placement in the canine thoracolumbar spine between 3D-printed patient-specific drill guides (3DPG) and the conventional freehand technique (FH). STUDY DESIGN: Ex vivo study. ANIMALS: Cadaveric canine spines (n = 24). METHODS: Implant trajectories were established for the left and right sides of the T10 through L6 vertebrae based on computed tomography (CT) imaging. Customized drill guides were created for each vertebra of interest. Each cadaver was randomly assigned to one of six veterinarians with varying levels of experience placing vertebral implants. Vertebrae were randomly assigned a surgical order and technique (3DPG or FH) for both sides. Postoperative CT images were acquired. A single, blinded observer assessed pin placement using a modified Zdichavsky classification. RESULTS: A total of 480 implants were placed in 240 vertebrae. Three sites were excluded from the analysis; therefore, a total of 238 implants were evaluated using the FH technique and 239 implants using 3DPG. When evaluating implant placement, 152/239 (63.6%) of 3DPG implants were considered to have an acceptable placement in comparison with 115/248 (48.32%) with FH. Overall, pin placement using 3DPG was more likely to provide acceptable pin placement (p < .001) in comparison with the FH technique for surgeons at all levels of experience. CONCLUSION: The use of 3DPG was shown to be better than the conventional freehand technique regarding acceptable placement of implants in the thoracolumbar spine of canine cadavers. CLINICAL SIGNIFICANCE: Utilizing 3DPG can be considered better than the traditional FH technique when placing implants in the canine thoracolumbar spine.

Computed Tomographic Evaluation of Safe Corridors for Pin Placement in Rabbit Thoracolumbar Vertebrae and Sacrum.

OBJECTIVE: The aim of this study was to identify safe corridors for pin placement in the terminal thoracic vertebrae, lumbar vertebrae and sacrum of rabbits using computed tomography (CT) in cadaveric models. STUDY DESIGN: Computed tomographic imaging of 25 adult New Zealand white rabbit (Oryctolagus cuniculi) cadavers was evaluated. Safe insertion corridors at the cranial and caudal end cortical sections (ECS) of the vertebrae were determined using a multiplanar reconstruction software. Pins were placed to allow maximal bone purchase within the safe corridors. Post-procedure CT imaging was performed to evaluate the pin position. RESULTS: The median safe corridor height in the thoracic and lumbar cranial ECS (2.54 mm; 1.39-3.97 mm) was significantly lower than that of caudal ECS (3.98 mm; 1.66-5.53 mm; p < 0.001). The mean widths of the left and right sacral safe corridors were not significantly different. Of the 99 pins placed, 70.7% of the pins were appropriately placed without vertebral canal impingement. Errors included partial canal impingement (12.1%), complete canal impingement (5.1%), inadequate bone purchase (7.1%), placement into the intervertebral disc space (1.0%) or in the incorrect ECS than intended (4.0%). The odds ratio of successful pin insertion without canal impingement was 2.77 (95% confidence interval, 1.04-7.43; p < 0.05) times higher in the caudal ECS than in the cranial ECS. CONCLUSION: The corridor identified in this study can be used as a guideline for pin placement in the thoracic and lumbar vertebrae of New Zealand white rabbits. Further biomechanical studies are required.

Comparison of Two Stifle Exploratory Methods Using Mini-Arthrotomy for Diagnosis of Canine Medial Meniscal Pathology: An Ex Vivo Study.

OBJECTIVE: The main aim of this study was to compare the accuracy of stifle exploratory using either a stifle distractor (SD method) or a combination of Hohmann and Senn retractors (HS method) for diagnosing canine medial meniscal tears in cranial cruciate ligament-deficient stifles. STUDY DESIGN: Fifteen pairs of canine cadaveric pelvic limbs were used and cranial cruciate ligament were transected in all stifles. Paired limbs were then randomly assigned to one of five groups based on the tears created in the caudal pole of the medial meniscus: no tear, peripheral detachment, or a variation in three vertical longitudinal tears. A craniomedial mini-arthrotomy was performed by two observers and diagnosis of the medial meniscal status was made utilizing the HS and SD methods. Correct diagnosis of the meniscal tear was compared for both methods and observers. RESULTS: Correct diagnoses were made using the HS and SD methods in 24/30 and 24/30 cases for observer 1 respectively; and in 17/30 and 19/30 cases for observer 2 respectively. There was no significant difference in the correct diagnosis of meniscal tears within each observer between the two methods. CONCLUSION: Both HS and SD methods have equal accuracy for the diagnosis of canine medial meniscal pathology for a board-certified surgeon. Unassisted surgeons using the SD method for the evaluation of the medial meniscus are at no diagnostic disadvantage compared with assisted surgeons utilizing the HS method.

Effect of crude fiber and total dietary fiber on the calculated nitrogen-free extract and metabolizable energy content of various dog foods fed to client-owned dogs with osteoarthritis.

OBJECTIVE: To compare measurements of crude fiber (CF) and total dietary fiber (TDF) for various dog foods and their effect on the calculated nitrogen-free extract and metabolizable energy (ME) content, and to compare label-guaranteed and laboratory-analyzed macronutrient values. SAMPLES: 51 dog foods fed to client-owned dogs with osteoarthritis. PROCEDURES: Foods were analyzed for dry matter, ash, crude protein, acid-hydrolyzed fat, CF, and TDF. Metabolizable energy was calculated by use of a formula with modified Atwater factors and formulas recommended by the National Research Council that included both CF and TDF values. Linear regression analysis was performed to determine the correlation between CF and TDF values. RESULTS: Only a few foods failed to conform to the guaranteed analysis for all macronutrients except for CF, in which approximately 40% of the foods exceeded the guaranteed maximum values. The CF and TDF values were moderately correlated (r = 0.843). Correlations among CF- and TDF-based ME estimations were moderate with use of the modified Atwater formula and strong with use of the National Research Council formulas (r = 0.86 and r = 0.91, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Values for CF were the most variable of the macronutrients of the evaluated dog foods and results suggested that CF is an incomplete and inaccurate measurement of dietary fiber content and, thus, its inaccuracy may lead to inaccurate and variable ME values.

Physical activity patterns of free living dogs diagnosed with osteoarthritis.

Osteoarthritis (OA) affects about 90% of dogs > 5 yr of age in the United States, resulting in reduced range of motion, difficulty climbing and jumping, reduced physical activity, and lower quality of life. Our objective was to use activity monitors to measure physical activity and identify how activity counts correlate with age, body weight (BW), body condition score (BCS), serum inflammatory markers, veterinarian pain assessment, and owner perception of pain in free-living dogs with OA. The University of Illinois Institutional Animal Care and Use Committee approved the study and owner consent was received prior to experimentation. Fifty-six client-owned dogs (mean age = 7.8 yr; mean BCS = 6.1) with clinical signs and veterinary diagnosis of OA wore HeyRex activity collars continuously over a 49-d period. Blood samples were collected on day 0 and 49, and dog owners completed canine brief pain inventory (CBPI) and Liverpool osteoarthritis in dogs (LOAD) surveys on day 0, 21, 35, and 49. All data were analyzed using SAS 9.3 using repeated measures and R Studio 1.0.136 was used to generate Pearson correlation coefficients between data outcomes. Average activity throughout the study demonstrated greater activity levels on weekends. It also showed that 24-h activity spiked twice daily, once in the morning and another in the afternoon. Serum C-reactive protein concentration was lower (P < 0.01) at day 49 compared to day 0. Survey data indicated lower (P < 0.05) overall pain intensity and severity score on day 21, 35 and 49 compared to day 0. BW was correlated with average activity counts (P = 0.02; r = -0.12) and run activity (P = 0.10; r = -0.24). Weekend average activity counts were correlated with owner pain intensity scores (P = 0.0813; r = -0.2311), but weekday average activity count was not. Age was not correlated with total activity count, sleep activity, or run activity, but it was correlated with scratch (P = 0.03; r = -0.10), alert (P = 0.03; r = -0.13), and walk (P = 0.09; r = -0.23) activities. Total activity counts and activity type (sleep, scratch, alert, walk, and run) were not correlated with pain scored by veterinarians, pain intensity or severity scored by owners, or baseline BCS. Even though the lack of controls and/or information on the individual living conditions of dogs resulted in a high level of variability in this study, our data suggest that the use of activity monitors have the potential to aid in the management of OA and other conditions affecting activity (e.g., allergy; anxiety).

Repeatability and accuracy of fingertip pulse oximeters for measurement of hemoglobin oxygen saturation in arterial blood and pulse rate in anesthetized dogs breathing 100% oxygen.

OBJECTIVE: To evaluate the repeatability and accuracy of fingertip pulse oximeters (FPO) for measurement of hemoglobin oxygen saturation in arterial blood and pulse rate (PR) in anesthetized dogs breathing 100% O2. ANIMALS: 29 healthy client-owned anesthetized dogs undergoing various surgical procedures. PROCEDURES: In randomized order, each of 7 FPOs or a reference pulse oximeter (PO) was applied to the tongue of each intubated anesthetized dog breathing 100% O2. Duplicate measurements of oxygen saturation (Spo2) and PR were obtained within 60 seconds of applying an FPO or PO. A nonparametric version of Bland-Altman analysis was used. Coefficient of repeatability was the interval between the 5th and 95th percentiles of the differences between duplicate measurements. Bias was the median difference, and the limits of agreement were the 5th and 95th percentiles of the differences between each FPO and the PO. Acceptable values for the coefficient of repeatability of Spo2 were ≤ 6%. Agreements were accepted if the limits of agreement had an absolute difference of ≤ ± 3% in Spo2 and relative difference of ≤ ± 10% in PR. RESULTS: Coefficient of repeatability for Spo2 was acceptable for 5 FPOs, but the limits of agreement for Spo2 were unacceptable for all FPOs. The limits of agreement for PR were acceptable for 2 FPOs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that some FPOs may be suitable for accurately monitoring PRs of healthy anesthetized dogs breathing 100% O2, but mild underestimation of Spo2 was common.

Client perceptions of the value of veterinary anesthesiologist involvement with anesthesia and pain management, benefits of a preanesthetic consultation, and quality of care for dogs undergoing elective orthopedic surgery.

OBJECTIVE: To compare perceptions related to veterinary anesthesiologist involvement with anesthesia and pain management, benefits of a preanesthetic consultation (PAC) with an anesthesiologist, and quality of patient care between clients who did and did not participate in a PAC prior to their dogs' elective orthopedic surgery. SAMPLE: 80 dog owners. PROCEDURES: Owners of dogs undergoing elective stifle joint surgery participated in the study. Participants were randomly assigned to PAC and control groups (n = 40 participants/group). The PAC group participated in a PAC with an anesthesiologist and completed a written survey (12 items with Likert-type response options). The control group completed a similar survey (identical except for 2 statements related to the PAC experience) without participating in a PAC. Results were compared between groups by statistical methods. RESULTS: The proportion of clients in the PAC group who strongly agreed with the statements that a PAC was beneficial, their questions about the pet's anesthesia and pain management plan were answered, they knew who would perform anesthesia and what safeguards were in place, veterinary specialty hospitals should have an anesthesiologist on staff, they were willing to pay more to have an anesthesiologist supervise the anesthesia and pain management, and a PAC with an anesthesiologist should be standard of care in veterinary medicine was greater than that for control group clients. Responses to quality-of-care items did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Participating in a PAC was associated with more positive perceptions of anesthesiologists and knowledge about the anesthesia plan. Further research with a validated survey instrument is needed to confirm these findings.

Effect of implementation of a surgical safety checklist on perioperative and postoperative complications at an academic institution in North America.

OBJECTIVE: To evaluate the efficacy of a surgical safety checklist (SSC) in reducing perioperative and postoperative complications. STUDY DESIGN: Before-and-after intervention study. ANIMALS: Client-owned dogs (n = 633) and cats (n = 44). METHODS: Consecutive surgeries were enrolled in the study. The "before" phase consisted of 267 surgeries performed without an SSC (SSC- ) followed by 75 SSC- surgeries in which a trained observer was in the operating room to detect possible complications. An SSC was then implemented in the operating rooms during 1 week. The "after" phase consisted of 58 surgeries in which a safety checklist (SSC+ ) and an observer were used and 277 SSC+ surgeries without an observer. Complications were prospectively recorded when witnessed by the observer, and all other perioperative complications were retrospectively recorded from veterinary records and client telephone communication. RESULTS: There were more perioperative and postoperative complications when surgeries were performed without an SSC (140/342 [40.9%; 95% CI, 35.7%-46.4%]) than there were when surgeries were performed with an SSC (98/335 [29.3%; 95% CI, 24.4%-34.4%]; P = .002). Surgical checklist use, presence of an observer, American Society of Anesthesiologists score, and anesthesia time were all independently associated with the odds of complications. CONCLUSION: Implementation of an SSC in an academic teaching hospital decreased the odds of perioperative and postoperative surgical complications. CLINICAL SIGNIFICANCE: This study supports the use of an SSC to prevent surgical complications in veterinary teaching hospitals.

Computed tomographic study of safe implantation corridors in rabbit lumbar vertebrae.

OBJECTIVES: A study was performed to evaluate the lumbar vertebrae of domestic rabbits using computed tomography (CT) in order to identify safe corridors for implant insertion. METHODS: Computed tomography imaging of 20 adult New Zealand white rabbits was evaluated using three-dimensional multiplanar reconstruction, and safe corridors were determined. Following corridor determination, implant placement was performed, and imaging was repeated. RESULTS: The cranial and caudal endplates contained the majority of the vertebral bone stock, and were an average of 3.14 and 3.30 mm in length, respectively. The mean safe corridor angle was 62.9 degrees (range: 58.8-66.7), and the mean width of the corridor was 2.03 mm (range: 1.60- 2.07). Post-placement imaging revealed that 35% of the pins demonstrated errors of placement, most commonly canal impingement. CONCLUSIONS: The results of the corridor evaluation indicate that an insertion angle of approximately 60 degrees relative to the sagittal midline is appropriate for implant insertion in the lumbar vertebrae of New Zealand white rabbits. Additionally, due to the hourglass shape of rabbit vertebrae, the endplates provide maximal bone stock for implant purchase, so insertion should be attempted in these regions. However, the high percentage of errors in placement indicate the need to more clearly define entry points to access the canal, and highlight the challenges of appropriate placement in the small bones of rabbits.

Conservative Management of Hip Dysplasia.

Hip dysplasia (HD) is a common orthopedic condition seen in small animal patients that leads to osteoarthritis of the coxofemoral joint. The disease can be managed conservatively or surgically. The goals of surgical treatment in the immature patient are to either prevent the clinical signs of HD or to prevent or slow the progression of osteoarthritis. In mature patients surgery is used as a salvage procedure to treat debilitating osteoarthritis. Conservative management can be used in dogs with mild or intermittent clinical signs and includes nutritional management and weight control, exercise modification, physical rehabilitation, pain management and disease-modifying agents.

Femoral Head and Neck Excision.

Femoral head and neck excision is a surgical procedure that is commonly performed in small animal patients. It is a salvage procedure that is done to relieve pain in the coxofemoral joint and restore acceptable function of the limb. Femoral head and neck excision is most commonly used to treat severe osteoarthritis in the coxofemoral joint and can be done in dogs and cats of any size or age. The procedure should not be overused and ideally should not be done when the integrity of the coxofemoral joint can be restored.

INNOPLANT Total Hip Replacement System.

Total hip replacement is a salvage procedure that is done to alleviate discomfort secondary to osteoarthritis in the hip, which is most often a result of hip dysplasia. Commercially available total hip replacement implants for small animal patients are classified as cemented or cementless. The INNOPLANT Total Hip Replacement system includes modular, screw-in cementless components that were developed to improve implant stability by maintaining as much normal anatomic structure, and by extension biomechanics of the coxofemoral joint, as possible. As a newer system, there are few data and no long-term studies available in the veterinary literature.

Bioaerosol sampling for airborne bacteria in a small animal veterinary teaching hospital.

BACKGROUND: Airborne microorganisms within the hospital environment can potentially cause infection in susceptible patients. The objectives of this study were to identify, quantify, and determine the nosocomial potential of common airborne microorganisms present within a small animal teaching hospital. METHODS: Bioaerosol sampling was done initially in all 11 rooms and, subsequently, weekly samples were taken from selected rooms over a 9-week period. Samples were collected twice (morning and afternoon) at each site on each sampling day. The rooms were divided into two groups: Group 1, in which morning sampling was post-cleaning and afternoon sampling was during activity, and Group 2, in which morning sampling was pre-cleaning and afternoon sampling was post-cleaning. The total aerobic bacterial plate counts per m(3) and bacterial identification were done using standard microbiological methods. RESULTS: A total of 14 bacterial genera were isolated with the most frequent being Micrococcus spp. followed by species of Corynebacterium, Bacillus, and Staphylococcus. There was a significant interaction between location and time for rooms in Group 1 (p=0.0028) but not in Group 2 (p>0.05). Microbial counts for rooms in Group 2 were significantly greater in the mornings than in the afternoon (p=0.0049). The microbial counts were also significantly different between some rooms (p=0.0333). CONCLUSION: The detection of significantly higher airborne microbial loads in different rooms at different times of the day suggests that the probability of acquiring nosocomial infections is higher at these times and locations.

Sensitivity of low-field T2 images for detecting the presence and severity of histopathologic meniscal lesions in dogs.

The sensitivity of low-field magnetic resonance (MR) T2 images for predicting the presence of meniscal lesions was determined in 12 dogs with naturally-occurring cranial cruciate ligament rupture and three control dogs, using histopathology as the reference standard. Previously published grading systems were used to grade the severity of meniscal lesions on MR images, gross inspection and histopathology. Focal areas of increased signal intensity were detected in 11/12 symptomatic dogs and 3/3 control dogs. Lesions mimicking meniscal tears (pseudotears) were identified at junctions between meniscal margins and adjacent connective tissue in control dogs and dogs with naturally occurring disease. Histopathologic lesions were present in all menisci of both symptomatic and control dogs, including the menisci from two affected dogs that appeared grossly normal but were removed and submitted based on MR imaging findings. Histopathologic lesions identified included hyaline cartilage metaplasia and changes in the amount of ground substance and cellularity. The sensitivity of MR imaging for detecting the presence of meniscal histopathologic lesions was 90% in symptomatic dogs and 91% in control dogs. However, agreement between severity scores for the different tests was poor. Low-field MR imaging is a sensitive test for predicting the presence but not severity of meniscal histopathologic lesions in dogs with naturally-occurring cranial cruciate ligament rupture. Findings also supported previous studies indicating that histopathologic lesions can be present in dogs with grossly normal menisci. An improved grading system for comparing MR images and histopathologic severity of meniscal lesions in dogs is needed.

The effect of stifle angle on cranial tibial translation following tibial plateau leveling osteotomy: an in vitro experimental analysis.

This study was designed to determine the ability of tibial plateau leveling osteotomy (TPLO) to eliminate cranial tibial translation (CTT) through a loaded range of motion. Twenty-four large-breed canine cadaver limbs were compared. Each limb was placed in a custom designed jig at 120° of stifle extension under an axial load of 20% body weight. A force of approximately 10 N/s mimiced the action of the quadriceps muscle and allowed the limb to move from 120° to maximal extension. Positional data were acquired using electromagnetic motion-tracking sensors. Each limb was tested under normal, cranial cruciate ligament (CrCL)-deficient, and TPLO-treated conditions. Cranial tibial translation significantly increased after transection of the CrCL. The TPLO failed to normalize CTT within the CrCL deficient stifle; however, values trended towards intact values throughout the range of motion. The TPLO was more effective at higher angles of flexion. These altered biomechanics may help explain the continued progression of osteoarthritis in TPLO repaired stifles. This loaded model may serve as a method for future evaluation of other surgical techniques.

Frequency of incomplete urolith removal, complications, and diagnostic imaging following cystotomy for removal of uroliths from the lower urinary tract in dogs: 128 cases (1994-2006).

OBJECTIVE: To determine the effectiveness of cystotomy for complete removal of urocystoliths and urethroliths in dogs, the types and frequency of diagnostic imaging performed to verify complete urolith removal, the complications that develop as a result of cystotomy, and predictors of each of these variables. DESIGN: Retrospective case series. ANIMALS: 128 dogs that underwent a cystotomy for removal of urocystoliths, urethroliths, or both from 1994 through 2006. PROCEDURES: The following data were obtained from medical records: sex, body weight, number and locations of lower urinary tract uroliths identified in preoperative and postoperative imaging reports, types of imaging used for urolith detection, number of uroliths recovered during cystotomy, quantitative urolith composition, and major complications attributable to cystotomy. Objective criteria were applied to determine whether a cystotomy failed or succeeded and whether appropriate imaging was performed. Associations between potential prognostic factors and outcomes were statistically assessed. RESULTS: Effectiveness of cystotomy could be determined in 44 (34%) dogs, of which 9 (20%) had incomplete removal of uroliths. Appropriate postoperative imaging was performed for only 19 (15%) dogs, of which 8 had incomplete removal. Dogs with both urethroliths and urocystoliths were more likely to have a failed cystotomy than dogs with only urethroliths or urocystoliths. Complications developed in 5 (4%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Cystotomy was a safe and effective surgical procedure for removal of lower urinary tract uroliths in most dogs. Failure to remove all uroliths occurred in a substantial percentage of patients.

Effect of multi-planar CT image reformatting on surgeon diagnostic performance for localizing thoracolumbar disc extrusions in dogs.

Accurate pre-operative localization and removal of disc material are important for minimizing morbidity in dogs with thoracolumbar disc extrusions. Computed tomography (CT) is an established technique for localizing disc extrusions in dogs, however the effect of multi-planar reformatting (MPR) on surgeon diagnostic performance has not been previously described. The purpose of this study was to test the effect of MPR CT on surgeon diagnostic accuracy, certainty and agreement for localizing thoracolumbar disc extrusions in dogs. Two veterinary surgeons and one veterinary neurologist who were unaware of surgical findings independently reviewed randomized sets of two-dimensional (2D) and MPR CT images from 111 dogs with confirmed thoracolumbar disc extrusions. For each set of images, readers recorded their localizations for extruded disc material and their diagnostic certainty. For MPR images, readers also recorded views they considered most helpful. Diagnostic accuracy estimates, mean diagnostic certainty scores and inter-observer agreement were compared using surgery as the gold standard. Frequencies were compared for MPR views rated most helpful. Diagnostic accuracy estimates were significantly greater for MPR vs. 2D CT images in one reader. Mean diagnostic certainty scores were significantly greater for MPR images in two readers. The change in agreement between 2D and MPR images differed from zero for all analyses (site, side, number affected) among all three readers. Multi-planar views rated most helpful with the highest frequency were oblique transverse and curved dorsal planar MPR views. Findings from this study indicate that multi-planar CT can improve surgeon diagnostic performance for localizing canine thoracolumbar disc extrusions.