Introduction of fracture
The mandibular condyle is involved in forming the temporomandibular joint, and is one of the weak parts of the mandibular structure. Condylar fractures can occur after suffering direct or indirect external blows, and mandibular condyle fractures account for about 20%-30% of mandibular fractures, and such fractures, if not handled properly, can lead to complications such as joint ankylosis. An Jingang, Department of Maxillofacial Surgery, Peking University Oral Hospital
Surgical anatomy
The upper posterior end of the mandible is the condyle, and the upper end of the condyle expands into the condylar head, which forms the temporomandibular joint with the mandibular fossa of the temporal bone. The connection between the condylar head and the mandibular branch is the condylar neck, and the anterior and superior part of the condylar neck is the articular pterygoid fossa, where most of the fibers of the pterygoid extrinsic muscle are attached. After a condylar fracture, the condyle is often displaced anteriorly and medially by the pull of the extensor pterygoid muscle.
The temporomandibular joint consists of the articular fossa and articular tuberosity of the temporal bone and the mandibular condyle, with the joint capsule and ligaments wrapped around the periphery of the joint and the fibrocartilaginous disc between the articular surfaces. The main functions of this joint are involved in mastication, speech, and swallowing. Condylar fractures will inevitably damage other joint structures, develop traumatic arthritis, and later, joint ankylosis may also occur.
Fracture classification
(1) According to the side of the fracture: unilateral fracture, bilateral fracture.
(2) According to fracture site: condylar head fracture, condylar neck fracture, subcondylar neck fracture, sagittal fracture.
(3) According to the position of the displaced fracture block relative to the joint socket: displaced fracture and dislocated fracture.
(4) According to the mode of fracture displacement: no displacement, misalignment displacement, bending displacement, overlapping displacement.
Causes of fracture
Traffic accidents, violence, falls, especially high falls, can cause fractures of the condylar process.
Fracture diagnosis
The movement of the condyle can be felt by placing the fingers on the lateral side of the joint or in the external auditory canal and observing the movement of the mandible itself. If there is a unilateral condylar fracture, a subjective assessment is made by comparing the difference in condylar motion between the two sides. The absence of palpable condylar dynamics along with pressure pain is highly suspicious of fracture. Combined with the imaging manifestations, a clear diagnosis can be made.
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Medical history Ask about the cause of injury and whether there is post-injury coma.
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Clinical manifestations
(1) Swelling and pain in the preauricular region The outer pole of the condyle of the fracture is often painful with pressure and a bone rubbing sound, but for a dislocated fracture, the condyle may not be palpable.
However, in dislocated fractures, the condyle may not be palpable. Some condylar fractures may present with external auditory canal injury; in this case, they should be differentiated from fractures at the base of the middle cranial fossa and cerebrospinal fluid ear leakage.
(2) Occlusal disorders Unilateral condylar fracture, occlusion is skewed to the fracture side, early contact of ipsilateral posterior teeth, bilateral condylar fracture, mandibular recession, early contact of bilateral posterior teeth, and anterior teeth opening?
(3) Functional impairment The main manifestation is restricted mouth opening, which affects normal feeding and speech function.
(4) Facial deformity After the fracture is displaced, the lower jaw may be deviated and receded deformity may appear.
3.Imaging examination
(1) Plain film Generally, the mandibular surface body layer film and mandibular opening posterior anterior position are selected, but it is not good for intracondylar capsule fracture, especially sagittal fracture.
(2) CT CT axial and coronal views combined with 3D reconstruction images can clarify the diagnosis of condylar fracture and can guide the formulation of surgical plan.
Fracture treatment
(1) Non-surgical treatment Condylar fracture? If the relationship is normal, use the head cap and chin pocket to brake for 10~21 days, followed by physical therapy and mouth opening training. If the fracture is displaced and forms a misalignment? the occlusal relationship must be restored by intermaxillary traction. Intermaxillary traction can be performed by placing 2~3mm thick pads in the early contact area of the teeth. pad to restore the occlusal relationship, and then perform intermaxillary fixation for about 2~3 weeks, the lower the fracture position, the longer the fixation time. After that, mouth opening training was started, together with physical therapy in the joint area.
(2) Surgical treatment Condylar fractures with external displacement or dislocation, low condylar neck and subcondylar neck fractures with severe internal displacement or dislocation, with significant reduction of vertical height of ascending branch (>4mm) and secondary misalignment should be treated surgically. should be treated surgically. Surgery is best performed within 12 hours after the injury or when the fracture is 5 to 7 days old. The posterior maxillary (cricomandibular angle) incision is usually chosen for the surgical approach, and the fracture is exposed and then anatomically repositioned.
(3) Treatment of condylar fractures in children The treatment of condylar fractures in children is aimed at promoting functional reconstruction of the condyle, preventing joint ankylosis, and avoiding developmental deformities of the jaws. The incidence of joint ankylosis is about 1%; the incidence of jaw deformity is about 20%-30%. Condylar fractures in children are highly remodelable, and a new condylar process of near normal form can be formed by functional contouring after healing of the fracture dislocation. Therefore, early fractures should be treated conservatively for almost all types of fractures. A 1 to 2 mm thick soft? pad to lower the condyle and relieve symptoms in the acute phase. Simultaneous traction of the lower jaw forward and upward, with the ? pad to correct misalignment under the guidance of the pad and appropriate braking. After 7~10 days, mouth opening training, especially anterior extension opening training, is started. If the fracture is displaced, the vertical height of the ascending branch is reduced, and there is obvious mandibular recession or skew deformity, intermaxillary traction with splints or orthodontic devices should be used, and craniomandibular traction should be added if necessary to restore the mandibular position. Condylar fractures in children during the milking and replacement periods do not require strict repositioning of the occlusal relationship; it is crucial to restore the vertical height of the ascending branch and to do functional training as early as possible on this basis. If persistent mouth opening restriction is found for more than 4~8 weeks and forced mouth training has little effect, the possibility of joint adhesions and early ankylosis should be alerted, and surgery should be considered to release joint adhesions, followed by mouth opening training with physical therapy.
Postoperative precautions
After surgery, attention should be paid to the selection of the appropriate intermaxillary fixation period, the appropriate review period and frequency. Early detection of possible complications, scientific and reasonable postoperative physiotherapy and proper postoperative guidance to patients should be carried out. Wound healing should also be monitored, oral hygiene should be reinforced and proper dietary intake should be supervised. Occlusal management should also be provided for those patients who need further occlusal stabilization and early exercise should be encouraged for patients with stable occlusion.