Internal Fixation of a Complicated Mandibular Fracture in a Filly Using a String-of-Pearls Locking Plate Assisted by a 3D Printed Model

Abstract

Objective The aim of this study was to describe the successful surgical treatment of a complicated mandibular fracture with a 3.5 mm string-of-pearls (SOP) locking plate in a 5-month-old Appaloosa filly presenting with neurological signs. Study Design This is a case report. Results The neurological signs were due to severe head trauma and stabilized with medical treatment. Financial concerns initially prevented advanced imaging; radiographs identified a mandibular symphysis fracture, a fracture of the left vertical ramus that originated at the junction between the horizontal and vertical ramus and extended toward the coronoid process and rostral maxillary fractures. Following intra-dental wiring of the symphysis fracture, a lateral malocclusion developed. Computed tomography additionally identified fractures of the right wing of the basisphenoid bone, right zygomatic arch, left paracondylar process and the lateral body of the mandible. The vertical ramus fracture was repaired utilizing a 20-hole 3.5 mm SOP plate contoured to the ventral aspect of the angle of the mandible. A scaled (1:4) three-dimensional printed model aided pre- and intra-operative surgical planning. The filly was comfortable and eating well at the 4-week recheck. Radiographs showed good callus formation at the maxilla, healing of the mandibular symphysis and ramus. Just prior to the 10-week recheck, the filly suffered severe enterocolitis and was euthanatized. Conclusion The locking function of the SOP plate provided adequate stability for the fracture to heal without the expense of locking screws. The three-dimensional printed model aided in navigation of the complex fracture without the availability of fluoroscopy.