lassification
General considerationsControversy has surrounded all aspects of
fractures of the condylar process. There have been several proposed
classification methods of these types of fractures.Following, the
AO classification is presented along with a simplified version. The
AO classification allows for better communication between
radiologists and surgeons. On the other hand, the simplified
version better reflects the clinical treatment implications.
AO ClassificationThe condylar process and head is a subunit of
the mandible and is defined by an oblique line running backward
from the sigmoid notch to the upper masseteric tuberosity. The
condylar process is differed into three subregions: Head Neck
Subcondylar (caudal) areaAd by JoniCoupon|Close This Ad
Frontal view.
Three lines are used to define these subregions:1. The first
line parallels the posterior border of the mandible2. The sigmoid
notch line runs perpendicular to the first line at the deepest
portion of the sigmoid notch3. A line below the lateral pole of the
condylar head that is also perpendicular to the first line.Clinical
pearl: the neck region can be divided into high and low halves by
equally dividing the distance between the sigmoid notch line and
the lateral pole line.Ad by JoniCoupon|Close This Ad
Treatment implications simplified classificationIn contrast to
the descriptive, previously defined anatomical classification, a
more simplified one is outlined and used in the Surgery
Reference.The surgeon decides to treat condylar process fractures
in an open or closed method. To perform an open reduction and
internal fixation, there must be room in the superior fragment for
at least two screws fixing the same plate.Clinically, this equates
to open treatment of condylar neck fractures or subcondylar
(caudal) fractures (A). The surgeon may elect to place one or two
plates depending on the location and configuration of the
fracture.Fractures at a level where there is inadequate space for
two holes to be drilled for the plate (B) require special
techniques of osteosynthesis. For that reason, among others, most
surgeons choose closed treatment for these joint fractures.General
considerationsAd by JoniCoupon|Close This Ad
Fractures of the condylar process (unilateral or bilateral) can
occur in isolation. They are more often combined with other
mandibular fractures.Imaging
Routine diagnosis of this type of fracture should include
radiographs taken in two planes at 90 to each other; the minimum
requirement is a PA view and a panoramic view.CT or digital volume
tomography (DVT) imaging may be used as an alternative.Panoramic
view showing left condylar process fracture in association with an
anterior body fracture.
Townes (oblique PA) view of the above patient. X-ray taken at 90
to show displacement of left condylar process fracture. Vertical
shortening of the left mandible is noted along with the right
anterior body fracture.
CT scans give the surgeon the best information with regard to
fracture location, morphology, fragmentation, and associated
injuries.CT scan 3-D reconstruction illustrates right condylar
process fracture.
Coronal view of the above patient shows angulation and luxation
of the condylar process fracture.Clinical findings
The dental occlusion can give orientation about the fracture
location. With a unilateral condylar process fracture and
subsequent reduction of height in the ramus region, the clinician
will see an ipsilateral premature occlusion and contralateral open
bite. The dental midline will shift toward the side of fracture.The
occlusion shows premature contact on the right with the deviation
of the jaw to the affected side that is commonly seen with a right
mandibular condyle fracture.
Bilateral fractures with shortening and dislocation result in
anterior open bite with minimal deviation of the midline.
Pitfall: widening of the lower faceBilateral condyle fractures
associated with fractures of the symphysis and body region often
produce a widening of the mandible and subsequent malocclusion.
These fractures are very difficult to treat. Great care must be
taken when performing the open reduction and internal fixation of
the body fractures to assure the mandible is narrowed to its
pre-injury status. Failure to recognize and/or correct the widening
of the body fractures will prevent anatomic reduction of the
condylar fractures and subsequent occlusal and functional
complications.Bilateral condylar process fracture
CT and/or digital volume tomography (DVT) is extremely useful
especially in cases of high and/or intracapsular fractures of the
condyle.This coronal view demonstrates bilateral condylar process
fracture with displacement. On the patients right side there is a
condylar neck fracture with angulation and on the left side there
is sagittal condylar head fracture medial to the lateral pole. On
the right side, the height of the mandible is not reduced.The
increased width of the mandible in ramus/condyle region may
indicate that there is an associated fracture in the anterior
mandibular arch.Subcondylar fracture
Detail of a panoramic x-ray showing a subcondylar fracture.Neck
fracture
Example of (low) neck fracturePlain x-ray taken at 90 to
demonstrate displacement of condylar process fracture.Townes
and panoramic views of a (low) neck fracture.
Example of a (high) neck fracture3-D reconstructions are useful
in identifying fracture height, direction and severity of
displacement.This 3-D reconstruction illustrates a (high) neck
fracture with displacement. Note the associated anterior body
fracture of the contralateral side.Nondisplaced, nondislocated
fracture
Nondisplaced, nondislocated fractures suggest the presence of
periosteal support for stability and may not require open
treatment.X-ray in the PA plane shows no vertical shortening.
X-ray shows that no displacement occurred.BiomechanicsHunting
bow conceptThe mandible is similar to a hunting bow in shape,
strongest in the midline (symphysis) and weakest at both ends
(condyles). The most common area of fracture in the mandible is
therefore the condylar region.A blow to the anterior mandibular
body is the most common reason for condylar fracture. The force is
transmitted from the body of the mandible to the condyle. The
condyle is trapped in the glenoid fossa. Commonly, a blow to the
ipsilateral mandible causes a contralateral fracture in the
condylar region. If the impact is in the midline of the mandible,
fractures of the bilateral condylar region are very common.
Clinical findingsDirect trauma to the TMJ area is unusual but
may be associated with fractures of the zygomatic complex.With a
condylar fracture, there is very often shortening of the ramus on
the affected side. This will result in an ipsilateral premature
contact of the teeth. In case of bilateral fractures, the patient
may present an anterior open bite. The condylar fragment may be
displaced (most often laterally) based on the angulation of the
fracture and predominant muscle pull.Plating considerations
At the time of surgery, the decision is made whether to place
one or two plates. This decision is based on fracture morphology,
the amount of bone available to hold plates and screws, and on
surgeon preference.Ideally, two miniplates should be applied in a
triangular fashion with one plate below the sigmoid notch and one
plate along the posterior border.Ad by JoniCoupon|Close This Ad
As an alternative way of achieving the same stability, a single
heavier plate can be used where there is limited bone available for
plating. This plate is placed along the long axis of the condylar
process.General considerationsWith plate and screw systems,
micromovement of condylar fracture fragments is minimized. Correct
application along with good fracture reduction will lead to primary
bone healing and subsequent bone formation along the fracture
surface.Depending on the fracture location in the condylar region,
one or two plates are used. In high condylar fractures, due to bony
limitations, only one plate can be placed. In most cases, a
mandibular plate 2.0 with two screws on each side of the fracture
line is sufficient.Adequate mechanical stability is gained by use
of two adaptation plates or one stronger plate.Plate and screw
fixation used in condylar fractures allows immediate postoperative
function.AnesthesiaIn condylar fractures, muscle relaxation is
crucial.Several extraoral surgical approaches to the condylar
region can involve the facial nerve. During the soft-tissue
dissection, a nerve stimulator may be used to identify the facial
nerve. Chemical muscle relaxation will interfere with the use of a
nerve stimulator. However, once the bony fracture has been reached,
muscle relaxation may help the surgeon reduce and stabilize the
fracture.Therefore, a sufficient dose of muscle relaxant is
administered before the reduction maneuvers.Use of MMFWhen treating
condylar fractures, the surgeon may use arch bars or another form
of mandibulomaxillary fixation (MMF). However, reduction and
manipulation of the fracture may be best accomplished with the jaw
open. At some point during the plate and screw fixation, the
patient should be placed into occlusion. This may be accomplished
by an assistant holding the patient into occlusion while the
fracture is being plated. This minimizes the risk of postoperative
malocclusion.Additionally, many surgeons prefer the use of training
elastics in the postoperative period.Alternative: endoscopically
assisted ORIFThe endoscopic technique is an alternative treatment
technique for condylar fractures.The two most important advantages
of the endoscopic technique are the avoidance of face scars and
minimizing the risk of facial nerve injury. The disadvantages are
the necessity of endoscopic/special equipment and the specialized
training and experience required for this surgical
technique.Special considerationsFollowing special considerations
may need to be taken into account: Multiple fractures Edentulous
atrophic fractures ComplicationsClick on any subject for further
detail.2.Choice of implant and plate position one plateChoice of
implant for one plate fixationAd by JoniCoupon|Close This Ad
If only one plate can be used, the surgeon should opt for a
thicker plate and bicortical screws if possible.The plate used can
either be a mandible plate 2.0or preferably a small/medium locking
plate 2.0. A DCP 2.0 can also be used (for its strength but not for
its compression) as well as a large profile locking plate 2.0
because of their increased rigidity.In each side of the fracture
line, a minimum of two screws have to be inserted. Plates with or
without a center space can be used.Plate position and order of
screw insertionAd by JoniCoupon|Close This Ad
The plate should be positioned in the center of the condylar
region or close to the posterior border. The numbers indicate the
order of screw insertion.3.Choice of implant two platesChoice of
implants for two plate fixation
There are several options of plates that can be used with
condylar fractures:1. Two mandible plates 2.0 (2-hole and 4-hole,
or 4-hole and 4-hole)2. Combination of a mandible plate on the
anterior border of the condyle and a compression plate 2.0 (4- or
5-hole DCP) without using the compression effect (screws in neutral
position)3. Two locking plates 2.0 (small and small/medium
profile).Thicker plates are usually best fixed with bicortical
screws.Lastly, mandible and locking plates 2.0 are preferred over
compression plates by many surgeons.In the following procedure, a
combination of a 2-hole with a 4-hole mandible plate 2.0 is
shown.4.ReductionReduction strategy
It is advantageous if the condylar fragment is already displaced
laterally (lateral override). However, the most common displacement
of the condylar fragment is medial, by pull of the lateral
pterygoid muscle. If the fragment is displaced medially, the
surgeon must manipulate it and convert it into a lateral override
situation.Then the plate can be applied and fixed with one screw to
the condylar fragment while it is supported by the underlying
mandibular ramus. Using the plate as a handle, the condylar
fragment can be reduced anatomically.Intraoperative image shows
angulation and lateral displacement of the condylar fragment.One
plateIf the use of only one plate is possible, the plate should be
centered over the long axis of the condylar process.Two platesIf
two plates are being used, the anterior plate is used to reduce and
initially stabilize the condylar fragment. The second plate is
placed parallel to the posterior border of the ramus.5.Reduction
one plateDrill hole for the first screw in condylar fracture
fragment
Drill a hole in the midaxis of the condylar fragment through the
plate hole closest to the fracture line using the 1.5 mm diameter
drill. The use of the drill guide is recommended to avoid injuries
in the soft tissues.Plate placement
Place the plate and insert the screw manually without complete
tightening. The aim of not tightening the screw completely is to be
able to apply traction to the fragments later in the
procedure.Manual traction
Reduction of the fracture is done under direct vision by
aligning the posterior border of the ramus.Pull the mandible
inferior and anterior in order to restore the posterior height of
the ramus and achieve reduction.The lower end of the plate prevents
the medial displacement of the condylar fragment during
reduction.
Clinical image shows the reduced fracture. The plate acts as
stop during the reduction and prevents medial displacement of the
condylar fragment.In this clinical example a 5-hole locking plate
without center space is used. The center hole is placed directly
over the fracture line and left empty.Pearl: use of bite block
To keep the jaw open and aid fracture reduction, a bite block is
placed in the molar region after placement of the first screw in
the plate.This results in posterior vertical distraction and
rotation of the mandible.Alignment of posterior border
In order to align the posterior border, pull traction on most
distal hole of the plate with a clamp.6.Reduction two platesDrill
hole for the first screw in condylar fragment
The first plate to be applied will simplify the fracture. In
this case the anterior plate is applied first.Drill a hole in the
proximal fragment with the 6 mm drill stop drill bit of 1.5 mm
diameter. The use of the drill guide is recommended to avoid
injuries in the soft tissues.Plate placement
Place the plate and insert the screw manually without complete
tightening. The aim of not tightening the screw completely is to be
able to apply traction to the fragments later in the
procedure.Manual traction
Reduction of the fracture is done under direct vision by
aligning the posterior border of the ramus.Pull the mandible
inferior and anterior in order to restore the posterior height of
the ramus and achieve reduction.The lower end of the plate prevents
medial displacement of the condylar fragment during
reduction.Pearl: use of bite block
To keep the jaw open and aid fracture reduction, a bite block is
placed in the molar region after placement of the first screw in
the anterior 2-hole plateThis results in posterior vertical
distraction and rotation of the mandible.Alignment of posterior
border
In order to align the posterior border, pull traction on the
small plate with a clamp (illustrated) or an angled hook.7.Fixation
one plateFixation of the plate
Place the inferior screw of the plate while the patient is in
occlusion.Completely tighten both screws at this time.Insertion of
additional screws
Fill the remaining screw holes in the order shown in the
illustration with additional screws and fully tighten them.
Completed osteosynthesis.
3-D CT reconstruction shows a one plate fixation using a large
profile locking plate 2.0.
Case example.
Another case example.8.Fixation two platesFixation of anterior
plate
Place the inferior screw of the anterior plate while the patient
is in occlusion.Completely tighten both screws at this
time.Templating
Check the proper alignment of the posterior border. If it is
properly aligned, adapt the plate. Sometimes, a template can be
beneficial if the lateral pole of the condylar head is approached.
However, use of a template is not always possible due to the size
of the surgical approach and fracture morphology.Plate bending
In the condylar neck and subcondylar region, the plate does not
require much bending. Bending is done using bending
pliers.Posterior plate application
Drill the first screw hole in the condylar fragment close to the
posterior border. It is recommended to drill the first hole without
the plate applied.Apply the plate and insert the first screw but do
not completely tighten it.
Place the plate parallel to the posterior border of the
ramus.Apply the second screw which is placed in the plate hole next
to the fracture line and fully tighten it. Then fully tighten the
first screw.Additional screw insertion
Fill the remaining screw holes with additional screws and fully
tighten them.Completed osteosynthesis
Clinical image shows the completed osteosynthesis.Option: plate
without center spaceAs an option for the anterior plate, a 3-hole
plate with empty center hole over the fracture is used.
X-ray of the completed osteosynthesis.AppendixNoteThe surgeons
personal expertise is the most important factor influencing the
decision-making process. Always choose the strongest possible
osteosynthesis.