Influence of plate type and placement on the immobilization of bilateral equine mandibular osteotomies: Ex vivo study

Treatment of a Mandibular Diastemal Fracture Using Locking Compression Plate and Cerclage Wire in a Mare

This report describes the combination of two surgical fracture repair techniques and the postoperative management of a mandibular diastemal fracture in a two-year-old mare. The mare was referred to a veterinary hospital with a laceration over the body of the right mandible. Radiographic assessment revealed two mesial fracture lines involving the second premolar tooth and a ventrally displaced bone fragment. The mare was treated under general anesthesia and the fracture was corrected using open reduction and plate fixation. A 3.5 mm narrow 15-hole locking compression plate with seven locking screws were used in a bridge form. Cerclage wire was also used to anchor the incisor teeth to the second and third premolar teeth. The cerclage wire and incisor teeth were covered with polymethylmethacrylate to prevent implant failure and avoid injury to the oral mucosa. Implants were removed 55 days after surgery and the mare was discharged from hospital five days later. The mare returned for cerclage wire removal after 90 days and was allowed to resume exercise thereafter. The combination of two surgical techniques, proper implant choice and appropriate postoperative management, including use of pelleted feed, contributed to successful bone healing and return to function.

Application of locking compression plates as type 1 external fixators to treat unilateral mandibular fractures in four equids and one dromedary

OBJECTIVES

To describe a novel fixation of open, unstable, unilateral mandibular fractures applying a locking compression plate as an external skeletal fixator (ESF-LCP).

ANIMALS

Four horses and one dromedary.

STUDY DESIGN

Short case series.

METHODS

Animals presented with unstable, open, unilateral fractures of the mandible. Fracture fixation was performed under general anesthesia. A 4.5/5.5 narrow LCP was applied externally above the level of the skin and combined with intraoral tension band wiring.

RESULTS

Fracture fixation was achieved successfully using an ESF-LCP. Minimal tissue manipulation was required during application and removal of the construct. The ESF-LCPs provided adequate access to the wounds at the fracture site, were well tolerated, and did not interfere with any objects in the animals' environment. Mild drainage at the screw-skin interface developed in all cases, requiring early implant removal due to surgical site infection in one case. The use of longer plates was associated with superficial pressure necrosis of the skin in the masseter area in two cases. Implants were removed after 3 to 12 weeks, and the long-term functional outcome after 11 to 41 (median 13) months was good in all cases.

CONCLUSION

Stabilization of mandibular fractures with ESF-LCP led to good outcomes in this case series. The use of longer plates positioned more caudally and in a ventrolateral position seemed associated with surgical site infection and pressure necrosis of the skin.

CLINICAL SIGNIFICANCE

Use of a locking compression plate as an external skeletal fixator seems to offer a viable alternative to treat unilateral mandibular fractures, especially when these are open and/or infected.

Polyaxial pedicle screw external fixation to stabilize oblique mandibular fractures in three standing, sedated horses

OBJECTIVE

To report the radiographic, surgical and postoperative features in horses with unstable oblique mandibular fractures secured with polyaxial pedicle screws (PPS) external fixation construct and intraoral wiring.

ANIMALS

Three client-owned horses.

STUDY DESIGN

Short case series.

METHODS

Two horses each had a unilateral fracture, which did not improve after conservative management, and one horse had bilateral fractures. Clinical and radiographic features were documented. Polyaxial pedicle screw external fixators and intraoral tension band wiring were applied in standing horses after combining sedation and regional nerve anesthesia. Intraoral wires were implanted through a lateral buccotomy between teeth (two horses) or burred through exposed crown (one horse) and then secured around the incisors. The PPS were inserted under radiographic guidance to avoid tooth roots. Healing was assessed with radiographic examination. The PPS external fixator rod and intraoral wires were removed first. The mandible was manipulated, and, if it was stable, the PPS were removed.

RESULTS

Implants were removed at 6, 8, or 10 weeks after the mandibles were palpably stable. Complications included broken wires in one horse, bone sequestration in one horse, and infection in one horse. Follow-up communication with the owners 12 to 18 months later confirmed complete healing without further complications of the fractured mandibles or teeth.

CONCLUSION

Polyaxial pedicle screw external fixation led to fracture healing and a return to function in all three horses. The complications encountered did not preclude a successful outcome.

CLINICAL SIGNIFICANCE

Polyaxial pedicle screw external fixation coupled with intraoral wiring provides an alternative to treat unstable equine mandibular fractures without general anesthesia.