2006 merck/merial - School of Veterinary Medicine - Louisiana State ...

used to label avian heterophils for identification by a Beckman Coulter Epics XL flow cytometer. The assay is optimized forhumans at 37°C and 10 minutes incubation time. Avian species have a higher average body temperature, ranging from 40-43°C. First, optimization of phagocytosis by heterophils was attempted by increasing the incubation temperature from 37°Cto 43°C. Secondly, the incubation time was manipulated from 5 minutes to 20 minutes. Preliminary results indicate that alonger incubation time at a higher temperature increases phagocytic activity of avian heterophils. Once the assay iscompletely adjusted for use in avian species, the mean number of phagocytizing cells will be determined in the control group(4°C) and the non-control group. In conclusion, we found that this assay can be used to differentiate heterophils using a flowcytometer. Evaluation of immune function is the next step.The Effect of Pilot Hole Drilling on Temperature of Cortical Bone and Drill Hole Accuracy in EquineCadaveric Third Metacarpal BonesElizabeth Barno*, Timothy LescunPurdue University School of Veterinary Medicine; Lafayette, INTransfixation casting is becoming a more widely and successfully used technique in the treatment of equine distallimb fractures. It is a modified form of external skeletal fixation which involves the placement of transcortical pins in intactbone proximal to the fracture site, which are then incorporated into a fiberglass cast. One of the major problems encounteredwith this type of casting is the loosening of these pins over time. Thermal bone damage that occurs at the time of pinplacement has been shown to contribute to premature pin loosening. This damage may also compound loosening attributedto infection or cyclic loading. It has been suggested that drilling sequentially larger holes to achieve a 6.2 mm hole for pininsertion may help to minimize heat generated in the cortical bone during drilling. It is unproven, however, that thistechnique actually reduces thermal damage. It is also unknown whether the drilling of pilot holes alters hole accuracy. Inthis study we will observe cortical bone temperatures in cadaveric equine cannon bones during the drilling of a 6.2 mm holewith and without pilot hole drilling. Temperature of the drill bit upon exiting will be also be recorded. The insertion torquerequired to place a transfixation pin will be observed as one measure of hole accuracy. Hole accuracy will also be measuredby the resultant hole diameter at three depths of the cortex as determined with digital calipers. We hypothesize that thedrilling of pilot holes will generate lower cortical temperatures immediately adjacent to the hole when compared to thedrilling of a single 6.2 mm hole. We also hypothesize that the accuracy of these holes will not be different when using eitherpilot hole drilling or a single 6.2 mm drill bit. The results obtained from this study may aid in developing an optimaltransfixation pin placement protocol which is vital to increase the success of transfixation casting.Evaluation of the Skelite Anterior Cervical Fusion Device in SheepRiccardo Beltramo*, Jason Hendry, Howard B Seim III D.V.M., Dipl ACVS, , A. Simon Turner, B.V.Sc., M.S.Dipl. ACVS.Small Ruminant Comparative Orthopaedic Laboratory, Colorado State University, Ft. Collins, CO 80523The objective of this study is to evaluate the Skelite Anterior Cervical Fusion Device in sheep. This device consistsin a ceramic cage made of calcium and phosphate that ultimately will be used to fuse one or more of the cervical vertebrae inhumans who have neck pain. Anterior cervical spine fusion surgery after discectomy in humans, frequently involves the useof bone graft and an anteriorly placed containment plate to improve stability, increase fusion rates, and prevent movement orsubsidence of the graft. Taking a bone graft from the iliac crest (pelvis) of a person is not without risks (postoperative painmonths later, nerve damage, infection). In an attempt to avoid complications from a bone graft, we are testing a new ceramicinterbody fusion device in the sheep cervical spine with a commercially available ventrally (“anteriorly”) placed plate toprevent extrusion of the device. During the surgery two discectomies are performed in each of ten sheep between vertebraeC2/C3 and C4/C5. The gaps between the vertebral bodies are filled with an autograft (previously taken from the sternum) orwith the Skelite Anterior Cervical Fusion Device. In this way, each sheep is treated with one control and one ceramicimplant. Our main objective is to determine if histological fusion occurs when the ceramic is used, and to determine theresultant biomechanical characteristics of the fusion mass. The fusion sites (autograft versus ceramic device) will becompared in each animal. Evaluations will be made at 3 months (6 sheep) and 12 months (4 sheep). Because of this delay theresults are not available now. This study is to assess the feasibility of eventually using this ceramic device in anterior cervicalspine fusion surgery in humans. Following Food and Drug Administration approval, this will be an important adjunct forspine surgery in the cervical vertebrae in people with neck pain.74