After wound debridement has been achieved and the trauma assessed, the fragments are reduced using one of several methods.
Repositioning hooks can be made easily from 2.0 mm or 2.6 mm Kirschner wire by creating a 90° angle. These hooks are introduced into bone fragments or intact bone through predrilled 3 mm holes or through small gaps between the fragments. Careful and controlled traction to the hook is applied and thereby the fragments are reduced into their normal anatomical position. Usually several holes are drilled so that the traction force is evenly distributed.
Alternatively, periosteal elevators or Langenbeck retractors can be effectively applied through small gaps between the fragments for fracture reduction.
In addition, a specially designed reduction instrument, manufactured in two sizes (2.4 mm and 3.5 mm), has recently become available. It consists of a horizontal cross handle, connected to a tap-like rod that is twisted into the bone fragment through a previously prepared hole.
Of all the various instruments that are available, these are best suited for the use in horses. Depending on the size of the fragment a 1.8 or 2.4 mm drill hole is prepared and the instrument inserted into the bone fragment.
Occasionally it is necessary to trim the bone fragments to facilitate correct anatomic repositioning and fracture reduction.
Once the fragments are reduced into proper alignment, holes of approximately 2 mm in diameter are drilled into the bone fragments. Care should be taken to maintain reduction at the time of drilling.
1 mm or 1.2 mm (20 or 18 G) cerclage wires are used to tie each fragment to the intact bone.
Pitfall: Great care should be used when tightening a cerclage because the bones of the facial skull are usually thin and easily cut by the wire.
The skin overlying the fracture should be sutured whenever possible and the use of distant relief incisions usually facilitates primary skin closure. However, primary wound closure is not always possible, particularly in fractures associated with extensive loss of bone, soft tissue- and skin damage. Many of these fractures and wounds heal surprisingly well via second intention and have a satisfactory functional and cosmetic outcome. Depending on the degree of contamination, a flush tube may be inserted into an injured sinus to facilitate flushing during follow-up treatment. Drains may also be required if dead space occurs between bone and skin.
A head bandage and padded head protection are applied to the patient during recovery from anesthesia.
The horse is maintained in stall rest for about two weeks followed by small paddock exercises for another two weeks.
Depending on the healing progress, nonsteroidal anti-inflammatory drugs and antibiotics are given for 3 to 5 days, or longer if required.
In most cases implants do not need to be removed provided that wound healing is normal and no persistent draining tracts develop.