condylar injuries (2).doc

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INJURIES OF CONDYLAR PROCESS

Introduction:Condylar fractures constitute about 25-30% of all mandibularfractures. Treatment policy for condylar fractures has aroused morecontroversy than any other subject in maxillofacial trauma. Fractures ofcondyle appear always to heal by bony union regardless of any therapy,unlike the rest of the mandible where non union is always a possibility.

The main controversies in relationship to condylar fractures relateto the basic philosophy of management. Three main schools oftreatment have evolved namely:-1. Conservative: This relies on the use of period of rest and

immobilization by intermaxillary fixation which may be for a short

period of 7-10 days to allow muscle spasm and telescoping to settledown as in unilateral fracture dislocation or alternatively it may be for4 weeks or more in bilateral fracture dislocations with an anterioropen bite.

2. Functional: Here the accent is an active movement. This is used incase of fractures with increased risk of ankylosis.

3. Surgical: Surgery may be considered for a fracture dislocation of thecondyle although bony union always appear to take place aspreviously mentioned. Surgical access is difficult as the condyletends to be pulled forward and medially by the lateral pterygoidmuscle and there is a risk of damage to branches of the facial nerve.

However a variety of surgical procedures have now been devised.Review of Literature with respect to incidence of condylar fracturesas a percentage of total mandibular fractures

Chalmers J Lyons Club (1947) has reported incidence of condylarfracture as 8%, Kromer (1953) 25%, Ekholm (1961) 27.7%,Schuchardt and Metz (1966) 25%, Rowe and Killey (1968) 35.6%,Tasanen and Lamberg (1975) 32.4%, Van Hoof et al (1977) 47%,Olson et al (1982) 52.4%, Andersson et al 40%, Ellis et al (1985) 29%, Haug et al (1990) 21%, Silvennoinen et al (1992) 52.4%General Nature of Injury:

The types of injury can be separated into three main groups:

1. Contusion of the soft tissues of the joint, which may involve either anavulsion of soft tissues, such as the ligaments, the synovium and themuscular attachment of the lateral pterygoid of an effusion causingformation of an inflammatory exudate or haemarthrosis. Rarely suchan effusion may be complicated by an infection resulting inpyarthrosis. If the contusion is severe results ranging frommicroinfarctions of the cortical layer to compression fractures of thecondyle are possible.The effect of a force in the direction of the ascending mandibularramus can be considerable without resulting in fracture, since thecondyle neck and condyle can withstand considerable stress in theaxial direction (whereas an obliquely acting force may result in


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fracture of the condylar neck even with little force). Furthermore indentulous maxilla and mandible the resulting pressure is absorbedlargely by the teeth. The effect of the action of a force on the chin

leads to a flexion fracture at the condylar process and is limited tocontusion only if the force is very small.2. Dislocation of the condylar head from the glenoid fossa is usually in

an anterior direction, but the displacement can be central, posterioror on rare occasions, lateral.

3. Fracture of the condyle itself either within the capsule involving thehead or neck or outside the capsule in the subcondylar region.The combination of above may occur for example fracture

dislocation where there is an extracapsular fracture of the condylar neckand the head that is displaced out of the fossa. In some cases thecapsule may also be ruptured in association with a fracture dislocation.

Mechanism of Injury:

What sorts of forces cause damage to the joint? Lindahl(1977)divided trauma causing condylar injury into three main groups.1) Kinetic energy imparted by a moving object through the tissues of a

static individual. This commonly results from trauma sustained from afist.

2) Kinetic energy derived from the movement of the individual andexpended upon a static object example is fall during an epileptic fit orfollowing a faint when the patient is unable to protect the face with anoutstretched hand as in the case of the so called parade ground

fracture.3) Kinetic energy which is summation of force derived from combination

of 1 + 2 and generally produces a severe type of injury such astypically occurs in road traffic accident.

Incidence of Fracture:

The incidence of condylar fractures in a large series of mandibularfractures may be as high as 35.6% (Rowe & Killey, 1968) with otherseries giving a somewhat smaller incidence (32.4%). Tasanan et al(1975); 27.7% (Ekholm, 1961). It has been suggested that the teeth mayprotect the condyle by cushioning the impact, but the role of the dentition

in protecting the condyle from indirect trauma is complicated. Theinfluence may depend on the angulation of the force and whether or notthe jaw is open at the time of injury.Imaging Techniques in Diagnosis:

Imaging techniques in diagnosis include conventional radiographylike orthopantomogram and lateral oblique view of mandible. ReverseTowns view and PA view of mandible, transcranial views, tomography,CT scan and magnetic resonance imaging.

OPG and lateral oblique view of mandible gives information ofoverall relationship of proximal and distal fragments in a anteroposteriorplane.


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Reverse Townes view and PA view of mandible gives informationof overall relationship of fragments in a mediolateral plane.

Transcranial view aid in defining relationship of condylar

fragments to glenoid fossa and also in delineating the pattern of highintracapsular fractures. The conventional tomography either in coronal orsagital planes (Ekerdal, 1973) has been useful in cases whereconventional radiographs have not been definitive. It is often morereadily available with a lesser cost than CT scanning or MRI. CT isparticularly indicated for suspected central dislocations of the condylethrough the glenoid fossa, where it will also demonstrate the presence ofany related intra or extra cerebral haematoma.

Magnetic resonance imaging (MRI) surface coil MRI haspermitted a very major advance in the diagnosis of the internalderangement of the temperomandibular joint (Harms et al, 1985).

Classification of injury to the bone of the temperomandibular joint:Dislocation:

Dislocation is a displacement of the condylar head completely outof the glenoid fossa, which usually cannot be reduced by the patient;subluxation on the other hand implies a displacement which the patientcan reduce himself.

Dislocations of the TMJ can be classified in different waysAccording to joint involvement- Unilateral- Bilateral

According to the extent

- Subluxation- Luxation

According to the direction of dislocation

- anterior- posterior- central or superior- Dislocations in the lateral or medial directions are possible

only if there is a concurrent fracture in the body of themandible (not identical to dislocation fractures in the jointregion)

Anterior (Heslop, 1956)

The condyle moves anterior to the articular eminence. This is byfar the commonest situation and represents a pathological forwardextension of the normal translatory movement of the head of thecondyle. An anteriolateral variant is described by Monis and Hutton(1957).


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Posterior (Helmy, 1957)

This implies a coexistant fracture of the base of the skull or theanterior wall of the bony meatus.

Central Dislocation (Zechal, 1977)

Superior dislocation into the middle cranial fossa must beassociated with a fracture of the glenoid fossa. The medial and lateralelevated margins of the fossa normally meet the articular surface of thecondyle on impact, thus protecting the central weak area of the fossaand this injury is probably most often related to a small bounded condylewhich fails to impinge on the margins.Lateral (Allen and Young, 1969)

These authors describe two subgroupsType I which is lateral subluxation

Type II a complete subluxation, where the condyle is forcedlaterally and then superiorly to enter the temporal fossa. An essentialprerequisite for lateral displacement is a fracture of the body of mandiblewhich occurs near the symphysis.

It should be emphasized that all the groups other than anteriordislocation are veryrare.Fracture:

There is a problem inherent in attempting to select a classificationfor fractures of condyle, for whilst a need exist principally for researchpurposes, for a comprehensive classification which differentiates the

numerous permuations of condylar derangement such a classificationmay prove too cumbersome for clinical use.

It is proposed to describe:1) a comprhensive; 2) A clinical system and to attempt to correlate them1. Comprehensive Classification:

This is based on that proposed by Lindahl(1977) and requires X-raysin two planes at right angles to each other.

For optimal localisation; the orthopantomogram, posteroanteriorprojection of the skull in a cephalostat, profile projection of the skull ina cephalostat axial projection of the skull and oblique transcranialprojections of the temperomandibular joint.

To describe a condylar fracture under this system, the followingdetails must be noted.a) Fracture levelThis may be1) Condylar head (CH) or intracapsular. It is difficult radiographically

to differentiate the exact anatomical confines of the head. Thisaccording to Grays anatomy extends only short distance downthe anterior surface of the process, covers the whole of thesuperior surface and descends for 5mm or more on the posteriorsurface. It is however quite possible to see the constriction of theneck in either anteroposterior or lateral projection and the head istaken as any part above this.


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By definition a condylar head fracture is within the capsule and istherefore termed intracapsular. Such fractures may be dividedinto vertical (anteroposterior sagittal split), compression

(producing a mushroom type of expansion) and comminuted. Ahorizontal subdivision would be difficult to differentiate from thenext category.

2) Condylar neck: The radiographic constriction representingcondylar neck corresponds anatomically to the region of theinferior attachment of the joint capsule.

3) Sub condylar: This is the region below the neck extending downto the most inferior point on the sigmoid notch anteriorly, while itsposterior limit is situated more inferiorly corresponding with thepoint of maximum curvature of the natural concavity of theposterior border of the mandible in that region.

b) Relationship of condylar fragment to mandibleThis maybe:(1) Undisplaced or fissure fracture(2) Deviated. This is a simple angulation of the condylar process

in relation to the main mandibular fragment without overlap.(3) Displaced with medial overlap of the condylar fragment(4) Displaced with lateral overlap(5) Anterior and posterior overlap are possible, but infrequently

seen(6) Without contact between fragments

c) Relationship of condylar head to fossa

The following relationship may be observed.1. No displacement. The joint space appears normal.2. Displacement

The joint space is increased, but the condyle is still related to theglenoid fossa.

Lindahl subdivided this into slight displacement and moderatedisplacement but quantification is difficult.3. Dislocation: Here the condylar fragment is completely out of the

fossa. The actual location of the fragment to the fossa can be

described and is usually anteriomedial.Clinical Classification:

Mac Lennan (1952) stressed that the more simple and practicalthe classification the more likely it is useful to prove. In his opinion therelationship of the fractured fragment to the remainder of the mandible isthe most important factor and he divides his classification into four maincategories.a) No displacementb) Fracture deviation

When there is simple angulation of the condylar process to the majorfragment. An example of this is the greenstick fracture of thechildhood.


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c) Fracture displacement where there is overlap of the condylar processand major mandibular fragments.

d) Fracture dislocation where the head of the condylar process has

been completely disrupted from the articular fossa.

The terms fracture deviation fracture displacement and fracturedislocation are useful. However the term fracture dislocation reallydeparts from the declared intention in the latter classification ofdescribing the relationship of the condyle to the rest of the mandible inthat it gives the position of condyle relative to glenoid fossa. Yet nplanning treatment for a fracture dislocation it is important to considerthe relationship of the condylar fragment to the mandibular stump. Forexample no contact of the bare ends might imply either wide separationof the mandibular stump from the glenoid fossa or such a close

approximation that there is a risk of ankylosis.Thus for example, a full description of a fracture dislocation might

be fracture of condylar neck, no contact of condylar fragment with themandible and dislocation of the condylar head from the fossa,mandibular stump not in contact with the glenoid.Complications of Condylar Injury:

The two most important complications of condylar injure are:a) Ankylosis b) Disturbance of mandibular growth.

Ankylosis:

Predisposing causes:

This is the development of significant or complete limitation ofmovement of temperomandibular joint by bone or fibrous tissue. Laskin(1978) has carefully evaluate the factors which could contribute to thedevelopment of post-traumatic TMJ ankylosis and these can besummarised.1. Age of patient:There is greater predisposition in younger than older patients andmajority of reported cases have sustained such injuries before the age of10 years (Topazian, 1964).2. Site and type of fracture:

The intracapsular fracture is having high risk of ankylosis. This isespecially so in children whereas pointed by Rowe (1969, 1982), theimmature thinly covered and highly vascular condyle may tend to burstopen, with resultant haemarthrosis containing multiple comminutedfragments of bone with a high osteogenic potential.Laskin considered that the most important feature in fractureencouraging ankylosis is close contact between glenoid fossa andcondylar stump and that this is more likely to occur with intracapsularfracture than with extracapsular fractures. Despite this only a relativelysmall number of cases of ankylosis occur in comparison with incidenceof intracapsular fractures. Laskin considers that damage to the meniscusis also an important factor which will be further discussed later.


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3. Duration of immobilization:Many authors point out the dangers of prolonged immobilization

but experimental work in primates (Markey, 1980) has failed to produce

ankylosis by this means after artificially produced condylar fractures. It islikely therefore that immobilization is a contributory factor rather than aprimary cause.4. Damage to Meniscus:

Laskin has suggested that the position and the state of the meniscusmay be the key factor in determining whether posttraumatic ankylosiswill develop. Even when there is close relationship of the condylar stumpto the glenoid fossa, the meniscus can act as a barrier to bony union, butif this is damaged or misplaced then ankylosis may occur as isdemonstrated by experimental evidence from animal studies (Wheat etal, 1977).

In Summary:The situations in which the risk of ankylosis is greatest comprise

1. Close proximity of the fractured condylar neck to the glenoid fossawhich is seen in:a) Intracapsular fracturesb) Fracture dislocation with gross telescoping

2. Compound fractures particularly when coronoid and zygomatic areasare also involved.

3. Patients under 10 years of age.Clinical Features:

1. Evidence of trauma facial contusions, abrassion, lacerations of thechin and echymoses and/or haematoma in the TMJ region.

2. Bleeding from external auditory canal. This finding may indicatefracture of anterior tympanic plate from a posteriorly displacedcondyle.

3. A noticeable or palpable swelling over the TMJ due to edema orhaematoma or secondarily to a laterally displaced condylar head thatis directly visible under the skin.

4. Facial asymmetry may be the result of soft tissue edema or may bedue to foreshortening of the ramus caused by the overlap of proximaland distal fracture segments.

5. Pain and tenderness to palpation over the affected TMJ6. Crepitation over the affected joint secondary to friction of the irregularfracture ends sliding over one another during manipulation

7. Malocclusion may be a useful clue to the type of injury sustained. Aunilateral condylar fracture usually results in ipsilateral prematurecontact of the posterior dentition secondary to foreshortening of theramus on that side. This foreshortening may also result incontralateral posterior open bite due to canting of the mandible.Bilateral condylar fractures may result in a marked anterior open biteand retrognathia. The medial pterygoid masseter muscles exert asuperior and posterior pull on the distal mandibular segment causing

it to telescope past the condylar segments. This telescoping results inpremature contact in the posterior occlusion with rotation of the


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mandible around this point and anterior open bite. Gagging on theposterior teeth may also occasionally be seen because of theposteriorly positioned mandibular segment.

8. Deviation of the mandibular midline may be seen both at rest andwith attempted excursion of the mandible.9. Muscle spasm with associated pain and limited opening10.Dentoalveolar injuries.MANAGEMENT OF CONDYLAR FRACTURESPrinciples of Treatment of Fractures:

According to the clinical data reported by Mac Gregor andFordyce (1957) bony union appears to occur after condylar fracturesregardless of whether intermaxillary fixation is employed or not andsimilar observations have been made in experimental fractures in therhesus monkey (Walkers, 1960; Boyne, 1967).

It has been intended to group the forms of treatment which havebeen advocated into two main schools of thought, conservative andsurgical.Conservative and Functional Treatment:

This is a term used to cover all methods of treatment other thansurgical intervention. Its objective is either to allow bony union to occurwhere there is no significant displacement of the condyle or in the caseof fracture dislocation, to produce an acceptable functionalpseudoarthrosis by re-education of the neuromuscular pathways. Itappears that bony union occurs regardless of treatment if there is

contact between proximal and distal fragments. These techniques areapplicable therefore in all cases of unilateral or bilateral fracture otherthan in certain gross displacements in superior or lateral directions orcertain other circumstances which will be detailed later.

The aims of conservative and functional treatment are toencourage active movement of the jaw as early as possible provided thatthe patient can bring his or her teeth into normal occlusion. Excessivepain or persistant malocclusion will require periods of intermaxillaryfixation. Such a period of fixation should not exceed 10 days if there is arisk of ankylosis in circumstances which has previously been outlined. Inthe case of children one must be aware of the remarkable remodelling

capacity of the condyle which may persist in many subjects into teenage.Dahlstrom et al in 1989 followed up 36 patients, 15 years after

conservative treatment of condylar fractures. In 14 children there was omajor growth disturbance observed and in most cases there were nosigns of the earlier fracture and function of the masticatory system wasgood. In eight teenagers the anatomical and functional restitution of theTMJ was not as good as in the children, but hardly gave rise to objectivesymptoms. In 14 adults signs of dysfunction were frequently observedbut not considered serious by the patients. The study involved carefulanalysis of the preceeding fractures clinical examination includingdetailed measurement of mandibular mobility, estimation of biting forceand radiographic analysis of the post treatment appearance of the


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articular fossa and the condylar head. Of the 14 adult patients assessednine reported persisting discomfort although this was never rated asserious. Subjectively altered appearance was reported by three subjects

and TMJ sounds were common in adult group. There was a significantreduction in the level of biting force.Konstantinovic and Dimtrifevic (1992) compared 26 surgically and

54 conservatively treated unilateral condylar process fractures bystandardized clinical examination and evaluation of computer stimulatedgraphic presentations of posteroanterior radiographs of the mandible.Surgical approach was through a submandibular incision with wireosteosynthesis. Using clinical parameter (maximal mouth opening,deviation, protrusion) no statistical differences between surgically andconservatively treated fractures were found. However the radiographicexaminations showed a statistically better position of the surgically

reduced condylar process fractures. At a minimum of 1 year aftertreatment the maximum mouth opening in both the groups has a meanof 3.9cm. A mean index calculated for deviation was 7.3% in bothgroups. In jaw protrusion also there was no significant difference. Inconservatively treated group however there were no complicationsduring the healing period, but in the surgically treated patients, four(15.4%) had infection of the wound and or transitory paresis of themarginal branches of the facial nerve.Surgical Reduction:

In this method the object is to perform a repositioning of the

fractured condyle as near to its anatomical location as possible. This isachieved by exposing the condylar fragment, reducing it to a normalrelationship with the mandibular fragment and then fixing it in thatposition.

As the results of conservative treatment are good overall with adysfunction rate of 15% it is essential to decide which cases merit asurgical approach.

Moreover surgical access in cases of fracture dislocations tendsto be difficult with areal risk to branches of 7 th cranial nerve and themaxillary artery. Zide and Kent (1983) have defined absolute and relativeindications for open reduction of condylar fractures which are a good

basis for practice. They are summarised below.Absolute Indications for Open Reduction:

1) Fracture dislocation of the condyle into the middle cranial fossa2) Impossibility of obtaining adequate occlusion by closed reduction due

to locking by the condylar fragment.3) Lateral fracture dislocation of the condyle4) Invasion by a foreign body (eg: gun shot wound)

This category would include most compound fractures of the condylewhere some degree of debridement and surgical toilet is indicated.

The authors suggest waiting for one week to allow resolution of

edema and haemarthrosis in cases where a condylar fragment appearsto be obstructing the attainment of a good occlusion. In the case of


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foreign bodies in the region of the joint, a wait of approximately 1 to 2weeks is recommended to allow for resolution of oedema so that somefibrosis will occur around the foreign body which will consist in its

isolation and retrieval.Relative Indications:

1. Bilateral condylar fractures in an edentulous patient where a splint isunavailable.

2. Unilateral and bilateral condylar fractures where splinting is notrecommended for medical reasons like, seizure, psychiatricproblems, alcoholism, retardation, secondary to neurologic injury,severe respiratory disorders.

3. Bilateral condylar fractures associated with comminuted midfacefractures. This is to allow reconstitution of a mandibular platform as astarting point in facial reconstitution n a very complex injuries.

4. Bilateral condylar fractures with associated gnathologic problemssuch as retrognathia or prognathism, open bite with periodontalprolems or lack of posterior support, loss of multiple teeth and laterneed for elaborate reconstruction. The authors comment that theserelative indications are arguable and patients may be treateddifferently by each surgeon and one would agree with thisassessment.

There fore four main surgical approaches to a fractured condyle.1) Al Kayat and Bramley (1978) type incisions allows the most direct

approach to high subcondylar and neck fractures.2) Submandibular approach - A Risdon type incision gives good access

for low sub condylar fractures. Care must be taken to avoid damageto the mandibular branch of facial nerve.

3) Intraoral approach - The incision used is similar to that for anintraoral subcondylar osteotomy. It gives good access for lowsubcondylar fractures.

4) Face life incision: Thishas been suggested by Zide and Kent (1983).This comprises a preauricular component together with an incontinuity post auricular component, much of which may be in thehairline.

It combines the advantages of the preauricular and

submandibular approaches but with better asthetics.The postauricular component allows the lifting of the massetermuscle from the lower part of the ramus to give access for low subcondylar fractures.

In particularly difficult cases the facial nerve may need to bedissected as a prophylaxis against damage and this is possible with thisincision.

Once the proximal condylar fragment has been located andreduced a variety of methods of immobilization have been described.Simple Soft Tissue Repair Without Fixation:

This was described by Silverman in 1925 and there is a report byRaveh et al (1989).


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It is combined with a period of intermaxillary fixation ofapproximately 10 days in the latter report. There must be a significantrisk of redisplacement due to the action of the lateral pterygoid muscle

although the results of the latter authors would appear to be satisfactorywith deviation of more than 4mm seen in only one case out of 29postoperatively.Methods of Immobilisation of the Condyle:Tranosseus Wining:

This is done through a submandibular incision for low subcondylar fractures especially that extending through the sigmoid notch.

First the major fragment is wired so that this may be used for adownward traction to improve access to the condylar fragment. Forpassing wire through the condylar fragment a pull through wire may be

used.For higher level fractures preauricular incision is used.In fracture dislocation transosseus wiring alone may be

insufficient to resist the displacing action of the lateral pterygoid muscleand one of the following additional methods may be employed unless themethod of detatching lateral pterygoid insertion described by Hendrick etal has been used. An alternative lassooing type technique has beendescribed by Messer (1972) which is claimed to give more stability.Bone Pins:

Archer (1975) described the insertion of pins into the condylar

head and neck which were connected with an external bar and universaljoints. The authors stated that this technique is rarely indicated and thisseems to be borne out in practice.

Thoma (1945) had previously described a similar techniques butplaced the pins in the condylar neck and zygomatic bone, this wouldneed to be combined with period of intermaxillary fixation.

Glenoidfossa-condyle suture: Wassmund (1935) described drillinga small hole through the lateral edge of the glenoid fossa and the relatededge of the condylar articulating surface. A chromic cat gut suture waslooped through and tied. It may however resorb and loosen prematurelywith unpredictable results as reported by Herfert (1961).

Kirschner Wire:

A Kirschner wire may be drilled vertically through the mainmandibular fragment from the angle avoiding the inferior alveolar bundle,so that it enters the fracture, interface and can be further inserted intothe condyle, which has previously been reduced (Lund, 1972) (Vero,1968). This technique has been modified by Brown and Obeid (1984)whereby Kirschner wire is inserted into the proximal condylar fragmentand after this a groove is cut for its base in the main distal mandibularfragment; two interosseus wires are then used to secure the basal partof the pin.


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Intramedullary Screws:

Petzel (1982) described use of intramedullary screw inserted

through a submandibular approach. Kitayama (1989) described the useof similar type of screw via an intraoral approach, specializedinstruments and considerable expertise is required.Bone Plating:

The use of small compact bone plates has tended to revolutionisepractice in relation to stabilizing the fracture proximal condylar fragmentand should be regarded as the method of choice in view of its rigidityand relative ease of application. Robinson and Yoon (1960) mentionedtwo holed plates while Koberg and Momma (1978) advocate a four holeplate which has tended to become standard.

Three useful plating techniques are described.1) Extraoral approach through the preauricular route2) Intraoral approach3) Osteotomy extracorporeal reduction technique through a

submandibular incision.Extraoral Approach Through Preauricular Route and Plating:

This has been described by Koberg and Momme (1978),Petzel (1982a) and Choung and Piper (1988).Surgical Procedure:The following are the stages1) Under general anaesthesia a preauricular Alkayat and Bramley

incision is made.2) Incision depended carefully in layers with plane superficial to

perichondrium of external auditory meatus.3) By careful blunt dissection the fractured surface of proximal fragment

is located and identified.4) Next step is gentle reduction into anatomical position of the proximal

fragment. A helpful technique is by insertion of a bone pin into theneck and manipulating the proximal fragment into its correct position.Extensive stripping of soft tissue attachment should be avoided inorder to reduce risk of ischaemic necrosis.

5) The jaws should be placed in intermaxillary fixation so that theproximal fragment can be manipulated into a correct relationship withthe distal segment. Once this is attained a miniature four hole plate ofWurzburg type is used to maintain the relationship.

6) The incision closed in layer A miniature suction drain helps inreducing echymoses.

7) It may be helpful in placing the patient in training elastics for 2-10days.

Intraoral Approach and Plating:

A technique for intraoral approach to the fractured condyle wasfirst described by Steinhauser (1964) and was amplified byNeiderdellmann (1986) and Jeter et al (1988). Lachner et al (1991)


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published the first results of a series of patients (14) who had beensurgically treated by intraoral open reduction of subcondylar fractureswith semirigid fixation by use of miniplates.

Surgical Technique:The following account is based on the technique described byLachner et al (1991). Early case selection confined, itself to displacedlow subcondylar neck fractures (extra capsular). The stages in theprocedure were as follows.1) Under general anaesthesia the subcondylar fractures were first

managed by the following technique and subsequently othermandibular fractures were treated.

2) Incision was put along the anterior border of ascending ramus.3) The masseter muscle was reflected laterally to the posterior border at

a subperosteal level.

4) The sigmoid notch was identified so that Bauer type retractor couldbe positioned on it.

5) The proximal segment was then carefully identified. If this proximalsegment was displaced medially the mandible was distractedinferiorly with Mason type gag to position the proximal segmentlaterally.

6) A four hole miniplate of Wurzburg type was then attached to theproximal segment with one or two screws. The periosteum of theproximal segment was elevated only to the degree necessary forplate placement so as to preserve as good as blood supply aspossible.

A percutaneous trochar was placed through a horizontal stabincision in the preauricular region (this should be done bluntly afterinitial skin incision so as to avoid damage to facial nerve branches)so that the correct angulation could be obtained for making the drillholes.

7) Intermaxillary fixation was instituted8) The plate was then attached to the distal segment with two further

screws.9) The incision was closed. Patients were training elastics between their

fixation bars for 2-10 days.

It is claimed that the intraoral technique obviates the knowncomplications of external open reduction such as the possibility of facialnerve injury external scar ischemic compromise to the proximal segmentand undoubted technical facilities.Submandibular Approach for Osteotomy Extracorporeal

Reduction Technique:

Mikkonen et al (1989) described access to a fracture dislocationof the condylar head through a submandibular approach which wascombined with a vertical subsigmoid osteotomy of the ramus to locatethe proximal fragment. The minor osteotomised segment plus thecondylar head were then reduced extracorporeally and firmly joined


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together before reimplantation in their correct anatomical position. Thisobviously required sectioning of the attachment of the lateral pterygoidmuscle to the condylar head. This technique which was originally

described in conjunction with intraosseus wiring has been modified asfollows for use with bone plates by Schnetler and Juniper (1992). In theirapproach a submandibular incision is made and the ascending ramusdivided between the sigmoid notch and the angle of the mandible usinga technique similar to that used in a vertical subsigmoid osteotomy. Bareminiplates are fitted and then removed prior to the completion ofosteotomy cuts. After the fragment is removed the dislocated head of thecondyle is readily visible and can be retrieved through the same incision.The fracture site at the condylar head can be reconstructed with easeaway from the patient and semirigid fixation applied using a miniplate.The reconstructed osteotomised ramus and condylar head can now be

reinserted through the wound and plated to the predetermined position.Downward traction on the mandible is usually required at this point andhas been achieved with a circummandibular wire brought out through thesubmandibular incision. Post operatively early mobilization of jaw isencouraged. The authors report three successful cases. They mentionedthe risk of a vascular necrosis but state that reports to date do notsuggest that this has been a problem.Specific Treatment of Condylar Fractures:

The following factors should be considered, that is:a) The age of the patient whether under 10 years of age, 10-17 yrs of

age, adults.

b) Whether the fracture is intracapsular or extracapsular (low condylarneck or high condylar neck)

c) Site whether unilateral or bilaterald) Whether the occlusion is undisturbed or whether there is

malocclusion.Children under 10 years of age:

This group has been shown to be more likely to develop growthdisturbance or limitation of movement than other groups. If malocclusionis present entirely as a result of condylar injury it should be disregardedbecause spontaneous correction will take place as the dentition

develops. Displaced condylar neck fractures will undergo functionalrestitution in most cases. Unilateral and bilateral fractures are treated thesame. Treatment should be entirely functional where possible. Indirectimmobilization by intermaxillary fixation is indicated for control of painand should be released after 7-10 days. Where an intracapsularfractures has been diagnosed careful follow up and monitoring of growthis required and treatment with myofunctional appliances instituted ifsubsequent mandibular development is reduced.Adolescents: 10-17 yrs. Of age the same principles apply to this groupwith same modification. If malocclusion is present the capacity forspontaneous correction is less than in younger group. Malocclusion is


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grossly displaced fragments may cause extra articular interference withjoint excursion.

When a bilateral fracture of this nature is associated with a major

mid facial fracture, operative reduction on both sides is desirable. Itshould be appreciated that this represents a considerable amount ofoperating time even in skilled hands. The situation may be temporarilysaved by the use of extraoral fixation utilizing a box frame or halo.

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