Long term outcome after surgical correction of mandibular brachygnathia with unilateral type 1 external skeletal fixation

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.

Treatment of class 2 malocclusion by corrective osteotomy using two short locking compression plates

Objective

To describe a symphyseal osteotomy stabilised with two short locking compression plates (LCPs) for treatment of class 2 malocclusions.

Study design

Case series.

Methods

Five horses (age range 8 months to 5¾ years) with overjets and/or overbites ranging from 6 to 32 mm and from 0 to 60 mm, respectively, were treated by osteotomy through the caudal third of the mandibular symphysis, cranial to the interdental space. After cranial distraction and ventral rotation of the rostral part of the mandible, two short (5/6 hole), bent 3.5 mm LCPs were applied ventro‐laterally and secured with two or three locking screws on each side of the osteotomy. In one case, the osteotomy gap was filled with bone marrow.

Results

Final outcome was good to excellent. Two cases needed a second corrective surgery, one because of non‐occlusion of the cheek teeth and another because of abaxial deviation of the rostral portion of the mandible. In three cases with a persistent fistula, LCPs were removed after bridging; drainage resolved and wounds healed. The time to bridging of the osteotomy gap ranged from 2 to 6.5 months. The procedure is technically challenging. It is important that the incisors are well aligned, which proved to be difficult when there was an abnormal maxillary incisor arcade. Incisors should not make contact when LCPs are fixed. The cheek teeth, however, should have good occlusion after positioning and fixation of the LCPs. Endodontic treatment of open incisor pulp cavities may be helpful.

Main limitations

The study population was small and relatively heterogeneous in severity. A larger population with more severe cases might have allowed for a more definitive assessment of the value of the technique for clinical practice.

Conclusions

This technique can be used to achieve a good correction for class 2 malocclusions. The approach provides adequate stability with smaller implants than other published techniques that require transection of both rami. The technique is less invasive and preserves the roots of the incisors and cheek teeth, as well as the mandibular canal.