Mandibular and Maxillary Fractures

1. Mandibular and Maxillary Fractures

2. List 3 considerations in repair of mandibular fractures caused by the presence of teeth. • Avoid iatrogenic trauma to teeth and associated neurovascular structures • Remove diseased teeth in fracture line • Restore correct dental occlusion • Small malalignments at fx may cause large malocclusion

3. How does the blood supply of the mandible restrict fracture repair, especially of rostral mandibular fractures? • Mandibular alveolar artery is sole supply to alveolar bone, periodontal ligament and teeth • Soft tissue attachments in rostral mandible must be preserved for revasularization of bone

4. What is the salvage procedure that may be used? • Rostral mandibulectomy

5. Describe the direction of the fracture line in stable and unstable fractures of the body of the mandible. • Stable: • Unstable:

6. When would external coaptation be indicated for a mandibular fracture? • Fx of body mandible • Bilateral or multiple fractures

7. How is this done? • ??? • Methylmethacrylate external bar is preferred- lightweight and versatile • External coaptation tape: tape around muzzle, then another piece of tape around back of head to muzzle, wrap it around muzzle then tape to back of head.????

8. What fracture is most common in the mandible of the cat? • Fx of mandibular symphysis

9. How is it repaired? • Repair with cerclage wire passed through skin ventral to jaw, into oral cavity, around mandubular symphysis, and out through skin • Wire is passed through hypodermic needles

10. When would an external fixator be used on the mandible? • For bilateral or multiple fractures

11. What are the requirements for owner care? • Owener must clean pin tracts several times each day

12. What is the triad of injuries seen with high-rise syndrome? • Thoracic trauma • Facial trauma • Fx of extremities

13. Describe postoperative management of the patient with fractures of the jaw. • Antibiotics if fx is open • Feed soft or liquid food for 4-7 days NG tube or gastrostomy tube may be indicated, esp in cats • With intraoral wounds or appliances, mouth must be rinsed daily

14. Surgical Conditions of the Coxofemoral Joint

15. Speculate on the reason that >90% of coxofemoral luxations in dogs and cats occur in a cranio-dorsal direction. • joint capsule is more lax in that direction pull of gluteals.

16. Can you think of a reason that this joint is traumatically luxated more often that the shoulder, although is more stable? • survive more often if hit that hard, also b/c see more bad hips in dogs

17. You see a 6-month-old standard poodle with a coxofemoral luxation of 3 days duration. No fractures are present. How should you treat this dog? • Perform a closed reduction of the hip • Externally rotate limb to bring head of femur below acetabular rim while applying distal traction • When head clears acetabulum, internally rotate limb • Apply medial pressure while joint is put through full range of motion, to clear debris from joint • Test for stability by lifting femur laterally • If stable, place in Ehmer sling fro 10-14 days

18. What is the prognosis with your treatment plan? • Good if less than 24 hours since injury • Failure of closed reduction is common if greater than 24 hours since injury

19. What other treatment options exist? • Open reduction • Leave alone

20. What are 2 contraindications to closed reduction? • If injury occurred more than 24 hours ago • In presence of fx or DJD

21. Do these same conditions preclude open reduction and stabilization? • No • But if patient is walking well on limb, do not do sx

22. What salvage procedures may be used? • FHO • Total hip replacement

23. Why has elimination of hip dysplasia by selective breeding been unsuccessful in purebred dogs? • Bc it is a polygenic inheritance = its not a gene you can select for and breed against it • Bc if select just for healthy hips will most likely loose specific characteristics of the specific breed. Specific breed characteristics are linked to bad hips

24. What could be done to make such a program more successful? • Nothing unless the owner is willing to give up the particular breed traits

25. Why is this disease of concern to you as a small animal practitioner? • Bc your hands are tied. • All you can do is help to keep these animals comfortable

26. Describe one preventative procedure that is often done. • Triple pelvic osteotomy • Also Pelvic symphodesis (not commonly done) • Also can be prevented if keep puppy caged • Early detection with Penn-Hip = must be certified to do

27. What is the goal of this procedure? • Triple pelvic osteotomy: improves dorsal coverage of head of femur by axial rotation and acetabular lateralization • Done on 5-8 month old dogs without radiographic evidence of DJD

28. What salvage procedures may be used?

29. What is Legg-Clave-Perthes disease? • Aseptic necrosis of femoral head • Hereditary predisposition, conformation, infarction of femoral head

30. What is the usual signalment and history associated with this condition? • Toy and small breed dogs • Hx: • Chronic weight bearing lameness • Acute non weight bearing lameness • Irritability • Inappetance • Chewing at skin over hip • Usually always unilateral

31. What is its etiology? • Unknown • Hereditary predisposition, conformation, infarction of femoral head • Blood supply to femoral head is occluded • Aseptic necrosis followed by revascularization occurs • Bone becomes weaker and collapses

32. What is the recommended treatment? • Femoral head and neck excision • Prognosis: very good