With increasing mandibular atrophy, the physical size of the mandible decreases. In the severely atrophic mandible, even very minor trauma can cause fracture. Additionally, pathologic fracture during mastication can occur. Very often, due to the fragile nature of the jaw, these fractures occur bilaterally.
Orthopantomogram (OPG), mandible series radiograph and CT scans can be used to diagnose and plan the treatment of the atrophic edentulous mandible fractures.
Axial CT scan showing bilateral fractures.
Note that although there appears to be a large bone stock, this patient’s mandible has only approximately 7 mm of vertical height.
Observation and soft diet
Observation may be indicated for patients medically unfit for general anesthesia. Atrophic edentulous mandible fracture patients are often elderly with medical problems presenting severe anesthetic risks.
One major complication of observation and soft diet would be nonunion of the mandibular fracture.
Closed reduction
Historically, atrophic edentulous fractures were treated closed by wiring in the patients dentures or fabricating Gunning style splints with postoperative mandibulomaxillary fixation (MMF).
Standard treatment with closed reduction often resulted in prolonged periods of MMF which was difficult for these patients. Additionally, the fractures were often poorly aligned. Postoperative malunions and nonunions were very common
ORIF
Indications for ORIF are any displaced atrophic mandible fracture requiring surgical intervention.
Following the AO principles of anatomic reduction of fractures and immediate function, ORIF of atrophic edentulous mandible fractures with load-bearing osteosynthesis has a distinct advantage for these patients. The technique has evolved to provide the patient with an excellent chance for mandibular union while the ability to masticate is preserved.
Literature has supported the efficacy of this technique.
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External fixation
Indications of external fixator might be the temporary stabilization of a fracture while the patient is treated medically, or if soft-tissue maturation around the fracture site is required.
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Complications,including malunion and nonunion are significant when external fixators are used as they do not provide absolute stability at the fracture site.
3 Treatment of an edentulous atrophic fracture with a reconstruction plate
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In the following, the treatment of an edentulous atrophic fracture with a reconstruction plate is described step-by-step.
4 Approach
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Extraoral appraoch
When treating atrophic edentulous mandible fractures, the surgeon will generally find it easier to use an extraoral surgical approach. The fracture fragments can be manipulated under direct visualization and stabilized while the reconstruction plate is being bent and applied to the mandible.
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Intraoral approach
An intraoral approach is possible but technically more difficult as the surgeon will need several sets of trained hands just to retract the soft tissues of the cheeks and tongue. Additionally, stabilization and fixation of the fractures is much more difficult via an intraoral approach. One should also be aware that the inferior alveolar nerve is located on the superior surface of the atrophic mandible. Therefore one must be extremely careful making intraoral incisions to expose atrophic fractures, or the nerve can be damaged.
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