Airway management

Airway management in open reduction, internal fixation of MAFs is often achieved through nasotracheal intubation. This allows the airway to be stabilized without the tube restricting the surgeon’s access. It also allows for the patient to be placed in maxillomandibular fixation (MMF) without issue. If there are concomitant facial fractures limiting access to a nasotracheal intubation, a submental intubation may be considered. In otolaryngology head and neck surgery practices, tracheotomy placement is a familiar technique that controls the airway without risking instrumentation of the nose in circumstances where skull base integrity is in question. Tracheotomy allows unfettered access to the oral cavity and the mandible during surgical repair of facial fractures of all types. Tracheotomy also has the advantage of being useful in the intensive care unit setting and allows for prolonged convalescence. However, a typical isolated mandible fracture without severe concomitant injury seldom requires airway control beyond nasotracheal intubation for the duration of the surgical case. One exception regarding airway control in mandible fractures may be in the circumstance of “bucket handle fractures” of the anterior mandible. This occurs when there are bilateral parasymphyseal fractures that allow collapse of the infraglossal musculature which can cause the base of tongue to relapse with subsequent airway obstruction. This constitutes an airway emergency that will require urgent airway control through intubation or tracheotomy.

Single plate versus two plates

Historically, immobilization of the jaw was the gold standard of care for all mandible fractures. If a fracture was surgically opened, wires were the primary means of fixation. However, the development of plating systems that allow for stabilization of the mandible with or without limited MMF has advantages. Early jaw mobility has been facilitated by internal fixation techniques with subsequent decreased concerns for weight loss, improved patient comfort, less risk of airway compromise, and faster return to active and normal function.

When approaching a MAF, several important factors must be considered. A key determination is the presence or absence of other mandibular fractures. The presence of other fractures may determine the order or technique of the approach. For instance, if there is a nondisplaced contralateral condyle fracture, this circumstance portends the need for guiding elastics, and the use of Erich arch bars will likely be the first step in fracture repair. Angle fractures are usually “retro-occlusal” in that they occur behind the articulated dentition. Therefore, if other fractures are present in the dentate segment of the mandible, it is these “occlusal” fractures that strategically are approached first. Fractures of the mandibular angle are often approached transorally through an incision proximate to the retromolar trigone or through a gingival incision that is described for third molar extraction. In the case of an isolated angle fracture, the fracture is typically completely exposed, and reduction is attempted before placing the patient into maxillomandibular fixation. Yet, maxillomandibular fixation would typically be a prerequisite to plating of the fracture as MMF is typically beneficial to achieving optimal fragment reduction. Temporary MMF techniques include the use of intermaxillary fixation (IMF) titanium screws, the use of Ivy loops, or the use of Ernst ligatures along with several other methodologies including a type of zip tie or embrasure wires. The instrumentation for the transoral approach to the angle uses transbuccal trocars for the plate and screw placement. It is beneficial to use threaded locking plates in the repair because the threaded locking plates can be secured directly to the transbuccal trocar to allow control of the plate while the repair is being secured and for drilling screw holes ( Fig. 1 ). Headlights and surgical magnification using loupes or endoscopes can improve visualization during the repair.

Threaded locking plates with transbuccal trocar. Transbuccal trocars and threaded locking plates can be used to control plate placement during transoral access.

Currently, the Champy technique for osteosynthesis is used preferentially for noncomminuted fractures of the mandibular angle. The Champy technique was popularized by Maxime Champy in the 1970s. Dr. Champy recognized that the angle of the mandible had certain characteristics that were favorable with regard to using a load-sharing engineering concept with regard to mandibular fixation. Load sharing is an engineering technique where forces caused by mandibular function will be counteracted by placing plates with monocortical screws in such a way that tensile or distractive forces are obviated while beneficial compressive forces are strategically promoted. This is in contrast to load-bearing repairs, whereby all forces at play on a functioning mandible will be overcome and neutralized by thick and rigid plates that have absolutely no mobility and use bicortical screw placement. The Champy technique uses optimal plate placement along Champy’s lines using monocortical screws that counteract tensile forces that occur during mandible function while allowing compressive forces to be controlled in the pursuit of bone healing ( Fig. 2 ). By using monocortical miniplates to counteract tensile forces, smaller and thinner plates can be used. Less surgical exposure and periosteum stripping is required, and less bone drilling is necessary. However, the Champy technique is not a rigid technique. It does allow some movement at the fracture site after repair. The Champy technique also relies on bone surface area contact to help stabilize the fracture, and therefore, comminuted fractures are not ideal for the technique ( Fig. 3 ). One other factor makes the angle an opportune place for utilization of this technique: the fact that angle fractures are actually behind the dentate portion of the mandible. Similar to sagittal split osteotomy surgery, the location of the angle fracture in this retro-occlusal zone allows leeway with regard to the precision of the final osteosynthesis as it relates to postoperative occlusion.

Champy’s lines. This mandible has drawn upon it a depiction of Champy’s lines. Monocortical plates placed along these lines counteract the tensile forces at play in mandibular function. Angle fractures may be controlled with a plate on the external oblique ridge ( blue arrow ) or on the lateral border of the mandible ( black arrow ) at the angle.

Sagittal view of angle fracture through a tooth socket. The black arrow points to a nondisplaced angle fracture, and the blue arrow points to a tooth socket which decreases contact surface area.

There have been numerous studies investigating the use of one versus two monocortical miniplates in open reduction and internal fixation of MAFs. Historically Michelet and colleagues, and later Champy and colleagues, introduced of the use of a single miniplate on the superior lateral border of the mandibular angle for osteosynthesis in MAFs ( Fig. 4 ). However, given the tensile forces of elevation on the mandibular ramus countered by the depressor forces on the mandibular body, later studies theorized that two miniplates should be placed, one superior and one inferior across the MAF ( Fig. 5 ). This has not been borne out in the literature as studies in which two points of fixation were used had higher complication rates than studies in which one miniplate was used. ^, A 2014 systematic review and meta-analysis by Al-Moraissi and Ellis found the use of one miniplate to be superior to the use of two, reducing postoperative complications (including dehiscence, infection, nonunion, malunion, malocclusion, and hardware failure). This corroborated randomized control trials of the same topic, showing that the use of two miniplates for MAF gave no additional benefit and increased both procedure time and risk of postoperative complication.

Single monocortical miniplate placed upon external oblique ridge along Champy’s lines. The classic placement of a single monocortical miniplate along Champy’s lines. Notice that the plate must be twisted to match the contour of the retromolar trigone.

Two miniplates at the angle. One plate is placed on the eternal oblique ridge ( red arrow ), and one plate is placed on the lateral superior border ( black arrow ). This is the so called two-plate approach. This technique was accomplished for bilateral angle fractures in this case. Two plates may resist twist and be a bit more rigid than one plate but have shown to have a higher complication rate. Often, when there are bilateral fractures, surgeons choose to use load-bearing repair techniques for one of the fractures. That was not done in this case.

Malleable plates

Malleable fixation plates are a bendable and less rigid version of the classic Champy plate, have a thin profile, and similarly use monocortical screws. The plate must be bent to the contour of the mandibular arch on which it is being placed but is malleable enough to allow final contouring to be formed by the screws as they are tightened and driven home. These plates were initially intended for non-load-bearing areas, such as the mid-face, however; they were adapted for MAFs after studies found one point of fixation to be superior to two for reduction of these fractures. Potter and Ellis were among the first to report on the use of these thin malleable plates with 1.3-mm screws, and while they were found to provide sufficient reduction, there was a high rate of intraoperative failure due to plate fracture upon fixation. In 2011, Esen and colleagues performed a cadaver study on sheep mandibles showing the use of a single thin malleable plate was not sufficient alone to withstand the forces generated by biting. Thus, a single thin malleable plate is not considered the gold standard of treatment for fracture osteosynthesis.

Lateral border

Although not original to Champy’s description, monocortical miniplate placement on the lateral boarder of the angle in a superior position has been shown to have the lowest complication rate in the literature ( Fig. 6 ). Specifically, plate dehiscence has an odds ratio five times lower if the plate is placed on the lateral mandibular surface rather than on the external oblique ridge. The success of this technique may have to do with having more facile operative access through the transoral approach for this position of plate placement. The Champy technique is based on obviating tensile force, and placement of a plate on the lateral boarder can accomplish that task efficiently.

Single monocortical miniplate placed on the lateral superior border. This placement of a miniplate on the lateral superior border of the mandible at the angle has the lowest complication rate for uncomplicated fractures.

The lateral inferior boarder also can be used for load-bearing rigid fixation using bicortical screws and thick plates designed to bear the complete load of mandibular function. Three holes on each side of the fracture would be considered the minimum optimal engineering necessary to accomplish safe immediate function. The placement of such thick and large hardware in this position is often accomplished through an external skin incision to allow optimal exposure for plate placement and plate contouring. The choice of this technique is made when fractures are comminuted, when the mandible is edentulous and atrophic with loss of alveolar bone stock, or when there is tooth loss which reduces contact surface area. Load-bearing approaches are also preferential in circumstances where infection is present ( Fig. 7 ).

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