Determination of the lateral extent of the subcutaneous wound bed in canine cadavers after closure of skin defects to replicate tumor excision.

OBJECTIVE: To determine the extent of subcutaneous involvement after primary closure of experimental skin defects. STUDY DESIGN: Experimental study. ANIMALS: Eight large, mixed breed dog cadavers. METHODS: Standardized, circular skin defects with diameters of 2, 4, 6, or 8 cm were created at the lateral thorax or abdomen by using a matrix to ensure even distribution, with eight defects of each diameter. The wound beds were covered in 60% barium sulfate paste prior to primary closure. Computed tomography and a dedicated viewing program were used to measure the distance from the edge of the subcutaneous defect to the incision at set intervals along the incision. RESULTS: The mean ± SD maximum lateral extension was 6.4 ± 1.9, 14.1 ± 4.9, 18.5 ± 6.9, and 26.0 ± 9.6 mm for 2-, 4-, 6-, and 8-cm defects, respectively. Extension >2 cm from the incision occurred in zero of eight, one of eight, five of eight, and six of eight defects after closure of 2-, 4-, 6-, and 8-cm defects, respectively. Extension >3 cm from the incision occurred in zero of eight, zero of eight, two of eight, and five of eight defects after closure of 2-, 4-, 6-, and 8-cm defects, respectively. CONCLUSION: The lateral extent of the subcutaneous wound bed extended past previously recommended revision margins of 2 to 3 cm in some defects measuring greater than 4 cm in diameter. CLINICAL SIGNIFICANCE: Surgeons and radiation oncologists should consider the potential extent of the subcutaneous defect when planning revision therapy, especially after large resections.

Influence of radiographic techniques on the measurement of femoral anteversion angles and a conformation score of pelvic limbs in Labrador retrievers.

OBJECTIVE: To determine repeatability of and correlation between 2 radiographic measurements of femoral anteversion angles (FAA) and to determine their influence on a score derived from tibial plateau angle (TPA) and FAA to predict the risk of cranial cruciate ligament disease (CCLD). STUDY DESIGN: Prospective clinical study. ANIMALS: Forty-eight Labrador retrievers with or without CCLD. METHODS: FAA and CCLD scores were calculated for each limb from extended pelvic radiographs (t-FAA) or angled (a-FAA) projections of the femur by 3 investigators. One investigator repeated measurements twice. Data were analyzed for repeatability, correlation between t-FAA and a-FAA, and their influence on CCLD scores. RESULTS: FAA correlated most strongly with the distance between the femoral head and the femoral axis on mediolateral radiographs, a measurement with excellent repeatability. t-FAA and a-FAA correlated with each other (r > 0.79, P < .0001), although t-FAA were about 1° greater than a-FAA (P = .01). Intrainvestigator and interinvestigator repeatability of the CCLD score was fair when derived from t-FAA and good to excellent when derived from a-FAA. CCLD scores differed between radiographic techniques but led to different predictions in only 9 (10%) limbs, all with lower TPA and CCLD scores than the rest of the population. CONCLUSION: a-FAA correlated strongly with t-FAA and improved the repeatability of CCLD scores within and between investigators. CLINICAL SIGNIFICANCE: A craniocaudal angled beam projection of the femur is a suitable alternative to a ventrodorsal pelvic radiograph when measuring FAA and may improve the repeatability and positive predictive value of CCLD scores.

Factors contributing to the variability of a predictive score for cranial cruciate ligament deficiency in Labrador Retrievers.

BACKGROUND: We recently reported that a conformation score derived from the tibial plateau angle (TPA) and the femoral anteversion angle (FAA), best discriminates limbs predisposed to, or affected by cranial cruciate ligament disease (CCLD), from those that are at low risk for CCLD. The specificity and sensitivity of this score were high enough to support further investigations toward its use for large-scale screening of dogs by veterinarians. The next step, which is the objective of the current study, is to determine inter-observer variability of that CCLD score in a large population of Labrador Retrievers. A total of 167 Labradors were enrolled in this cross-sectional study. Limbs of normal dogs over 6 years of age with no history of CCLD were considered at low risk for CCLD. Limbs of dogs with CCLD were considered at high risk for CCLD. Tibial plateau and femoral anteversion angles were measured independently by two investigators to calculate a CCLD score for each limb. Kappa statistics were used to determine the extent of agreement between investigators. Pearson's correlation and intraclass coefficients were calculated to evaluate the correlation between investigators and the relative contribution of each measurement to the variability of the CCLD score. RESULTS: The correlation between CCLD scores calculated by investigators was good (correlation coefficient = 0.68 p < 0.0001). However, interobserver agreement with regards to the predicted status of limbs was fair (kappa value = 0.28), with 37% of limbs being assigned divergent classifications. Variations in CCLD scores correlated best with those of TPA, which was the least consistent parameter between investigators. Absolute interobserver differences were two times greater for FAAs (4.19° ± 3.15) than TPAs (2.23° ± 1.91). CONCLUSIONS: The reproducibility of the CCLD score between investigators is fair, justifying caution when interpreting individual scores. Future studies should focus on improving the reproducibility of TPA and FAA measurements, as strategies to improve the agreement between CCLD scores.