Background

Over the years, the treatment to be chosen for the resolution of condylar fractures has been discussed with great concern. Treatment depends on the type and location of the fracture, associated facial injuries, as well as concomitant diseases. It can range from functional therapy without maxillomandibular fixation (MMF), closed reduction with MMF, to open reductions with osteosynthesis plates⁷.

Some authors establish that most condylar fractures are treated by closed reduction, due to the good results of the majority of the patients treated by this management⁸. The treatment for condylar fractures in children becomes more complicated due to the poor cooperation and difficulty when placing MMF and reduced space in mandible and maxillae with developing teeth. The methods of temporary immobilization involve arch bars, acrylic splints, MMF screws, and bonded brackets with the use of heavy elastics. The recommended period of immobilization oscillates from 1 to 2 weeks to allow early bone healing, followed by active mobilization of the mandible as an immediate indication to avoid ankylosis, aided with the use of elastics for 6-8 weeks to restore and obtain desirable occlusion. Studies establish good results in regard to masticatory function and patient satisfaction. In patients younger than 12 years, the adaptive mechanisms should restore function without immobilization, for which early mobilization is instructed. Patients with major disruption of occlusion and patients with risk of ankylosis or defective development, have to be the reason for alert and caution. Occlusal impairment, consisting of open bite and possible retropositioning of the mandible, may be a consequence of bilateral fracture dislocation. Treatment in these cases should be immobilization, as well as for an adult. In instances where unilateral condyle fracture with occlusal disruption is present, a period of 10-14 days should be assumed. In bilateral fractures immobilization of 3 weeks may be required. Young patients with a probability of ankylosis or defective development respond to either close proximity of the fractured condylar neck to the glenoid fossa or those who have multiple fractures with associated coronoid and zygomatic fractures. In these cases, it must be presumed that the meniscus and/or capsule is damaged, for which a conservative immobilization may be used in case the patient has minimal symptoms. Otherwise, in case of severe pain, MMF is recommended for no longer than 14 days, followed by active mobilization, due to the greater osteogenesis of condylar progress and remodeling capacity. In adolescent patients between 12 and 17 years old, if a malocclusion is present, the capability for spontaneous correction is less than in younger patients. Therefore, a malocclusion indicates MMF for 2-3 weeks. If the conservative treatment fails in this age group, the clinician would have to employ adult principles of treatment⁹,¹⁰.

The protocol of closed reduction for adults includes mandibular exercises such as maximum opening, laterality, and protrusion, in which movements of 5-10 repetitions of 2-4 times a day during 3 months of rehabilitation must be done¹¹,¹². Arch bars are also placed to guide the occlusion with elastics and achieve an optimal opening of 40 mm interincisal, using them from 1 to 4 weeks and kept under observation for 3 more months¹²,¹³. This protocol is carried out to mobilize the components early and restore physiological functions, avoiding some type of ankylosis¹¹.

It is considered that the temporomandibular joint is an area that can result in complications involving the VII cranial nerve, as well as other associated complications. Likewise, there may be technical problems at the moment of manipulation of the fractured segments toward their anatomical position, due to comminuted fractures, fragment size, or fracture characteristics. Finally, the necessary approach to open reduction may result in a scar⁸,¹³.

Within the problems that could be presented in cases of articular fractures treated with a closed reduction, not only are early dysfunctions but also late joint changes in the next 10-50 years in the joint not found in an adequate anatomical position. There are also short-term problems, such as pain, dysfunction, limitation of opening, and deformities such as retrognathia, asymmetry, or open bite. On the other hand, long-term sequelae associated with the technique used for closed reduction, such as pain, arthritis, and movement limitation, could also present with open reduction. That is why the surgeon must perform an analysis based on specific criteria of the case in question to determine the treatment and management of the fracture to be treated⁸.

To determine and provide the best treatment when performing the analysis of the patient in question, there are criteria that support the specific conditions in which condylar fractures occur. These criteria are established by means of absolute and relative indications to perform open reduction with internal fixation that will help the surgeon make a more accurate decision regarding the treatment to be performed.

The indications for open reduction are: (1) Displacement toward the middle cranial fossa, (2) failure to obtain adequate occlusion by means of closed reduction, (3) lateral extracapsular displacement of the condyle, (4) intrusion of a foreign object, (5) loss of posterior facial height, (6) loss of vertical height greater than 4 mm, and (7) angulations of 30° or greater. Likewise, indications for open reduction refer to condyles displaced outside the fossa and associated with malocclusions. These include (8) bilateral condylar fractures in edentulous patients where MMF is impossible due to alveolar atrophy present, (9) unilateral or bilateral condylar fractures where MMF is not recommended for medical reasons or problems in which physiotherapy is impossible (patients with seizures, psychiatric problems, alcoholism, reluctant behavior, mental retardation, or delayed neurological trauma), (10) bilateral condylar fractures associated with comminuted fractures of the middle third of the face, and (11) bilateral condylar fractures associated to gnathological problems such as retrognathia, prognathism, open bite with periodontal problems or non-existent posterior support, absence of multiple dental organs and bilateral condylar fractures with unstable occlusion due to orthodontics and unilateral fractures with an unstable fracture base. An additional indication was any condylar process fracture in which a bony union and immediate function were desired⁸,¹⁴-¹⁶.

The displacement toward the middle cranial fossa is not very frequent in incidence; however, it has been reported. Similarly, the lateral displacement is not very incident; however, it has been presented. Foreign bodies should be removed from the joint; however, a period of approximately 1-2 weeks is recommended to allow the edema to diminish so that fibrosis forms around the foreign body and allows it to be isolated and easier to handle at the time of removal⁸,¹³.

Intracapsular fractures of the mandibular condyle head are mostly treated in a closed manner in most institutions since good results have been demonstrated. The type of fracture and its intracapsular location determine the prognosis after a closed functional treatment of condylar head fractures; the worst being those that are found comminuted¹⁷,¹⁸. However, nowadays, reports have been published about benefits of surgical treatment in these type of fractures, taking into consideration the advances in surgical techniques and imaging, such as the computerized tomography (scan)¹⁸. The keys for successful open reduction and rigid fixation of intracapsular fractures are: good exposure, anatomic reduction without damaging the cartilage surface of the condyle and lateral pterygoid muscle, stable fixation, and disc reposition¹⁹-²¹.

There are several factors to evaluate and to determine the method to be used for open reduction, in which the following stand out: (1) position of the condyle, (2) location of the fracture, (3) time of evolution of the fracture, personality of the patient, edema volume, place of approach, and type of fixation. It is preferable to determine if the condyle is in the fossa, and if so, the fracture will heal under acceptable conditions in proper position and function after the restoration of occlusion and physiotherapy⁸.

The choice of approach to be performed depends on the location of the fracture line. The submandibular approach, occasionally referred to as the Risdon approach, can be used for access to the mandibular region, angle and body fractures, and condylar fractures. It is precise to recognize very important structures that associate to the region, such as the marginal mandibular branch of the facial nerve, facial artery, and facial vein to proceed with the incision and dissection. The incision in the submandibular approach is carried through skin and subcutaneous tissues to the level of the platysma muscle. The superior portion of the incision is undermined approximately 1 cm, and the inferior portion is undermined approximately 2 cm or more. The retromandibular approach exposes the entire ramus from behind the posterior border; therefore, it is useful for exposure of the condyle neck. The anatomical structures that have to be taken into consideration in this area correspond to the facial nerve and the retromandibular vein. The incision for this approach begins 0.5 cm below the earlobe and continues inferiorly 3-3.5 cm, and it is placed just behind the posterior border of the mandible and may or not extend below the level of the mandibular angle. The preauricular approach is a standard to access the TMJ, and it comprehends several important anatomical structures in the area such as the parotid gland, superficial temporal vessels, auriculotemporal nerve, facial nerve, and the temporomandibular joint itself. The incision is held at the junction of the facial skin with the helix of the ear. A natural skin fold line along the junction may be used to minimize the scar. The incision extends superiorly to the top of the helix and may include an anterior extension²². The periangular approach, also referred to as high submandibular, or modified Risdon's approach, has been used to approach fractures of the condylar base. This approach provides good esthetics and drastically reduces the chance of facial nerve paraesthesia. The periangular approach involves a 3-5 cm curved incision, marked 1 cm from the angle of the mandible²³.

Diacapitular fractures are accessed by means of a preauricular approach or only by means of a preauricular approach. A subcondylar or neck fracture is accessed by means of a retromandibular or submandibular approach. Furthermore, the option of an intraoral approach is available (now with endoscopic assistance), which can only be used for neck fractures and fractures of the subcondylar type, since the access is limited and it hinders the direct visibility toward the site to be treated, it is an approach for surgeons with experience, however it avoids facial scars, facial nerve affection and provides constant visualization of the occlusion during the procedure. A fracture with the evolution of 2-3 weeks, is the maximum time to operate, is accessed by means of a combined submandibular and preauricular approach⁸,²⁴-²⁸.

There are various designs of plates as osteosynthesis material used to perform the internal fixation. The five main designs for performing osteosynthesis, as required on a case-by-case basis, are: (1) straight standard plate, (2) inverted Y plate, (3) delta plate, (4) trapezoidal plate, and (5) rectangular plate. The use of each of them depends on the fracture to be reduced, being the straight plate the most used, due to its high resistance²⁹,³⁰ (Fig. 3). Strut plates are also a three-dimensional plate option for transoral endoscopically assisted approaches, providing intraoperative handling and fitting accuracy, precluding complications such as plate fatigue fractures³¹.

Figure 3 A-C: Design of different osteosynthesis plates. 

The term and concept of rigid internal fixation are used to determine the application of an internal system to prevent movements at the fracture site when normal function forces are exerted. Within the above mentioned, reconstruction plates, high profile plates, and multiple screws are included. It is important to mention, to determine a good treatment plan, with a fixation system that maintains the fracture in question³²,³³. Open reduction and internal fixation of the condyle are irrational if the internal fixation is not sufficiently stable to resist physiological strains, becoming necessary numerous plating techniques. Trapezoidal condylar plates are a good option to stabilize subcondylar fractures, allowing the use of only one plate, fulfilling the principles of functionally stable osteosynthesis³⁴.

Application of miniplates has become, nowadays, the most common technique of open fixation. Nevertheless, anatomical and biomechanical limitations make it challenging when a considerable complication arises. Individual human mandible anatomy, bone density, position, and orientation of the masticatory muscles are some of the factors that play an important role in biomechanical behavior. The loosening of screws, bending instability of miniplates and plate fractures have been observed as a consequence of transferred loads and stress distribution in the bone and osteosynthesis system, due to the static and fatigue limits in miniplates.

Within the complex of biomechanical behavior of the mandible, bite forces associated to the reaction forces applied to masticatory muscles, such as masseter, temporalis, medial pterygoid, and lateral pterygoid, being the temporalis with a force of 329.2 N, the masseter with 272.0 N and the medial pterygoid with 174.8 N, the muscles with the greater proportion of acting force.

Force load configurations relay on biting with occlusal contact on the contralateral side of the fractured condylar process and biting with occlusal contact on the ipsilateral side of the fracture. After surgical treatment, the clinician should tell the patient to avoid loading of the mandible, yet patients do crunching and clenching with the teeth when sleeping and lifting substantial objects, contributing to loading risks and inadequate compliance of the patient.

Another element to discuss is the existence of full dentition or absence of it with or without an adequate occlusal relationship. This is critical to the stresses that might be excreted inside the condylar neck osteosynthesis devices; where full dentate patients will distribute evenly the bite forces. Although a patient with full dentition might exert higher masticatory forces, therefore, more load to the fracture and plates. It is important to know the fatigue limit for bending of titanium, which is approximately 450-500 MPa, to avoid exceeding the configurations, the equivalent stresses up to 2700 MPa definitely exceed the static yield limit of titanium. Due to the previous statements, it is recommended to use two fixation plates at the site³⁵.

Within the results after a closed or open reduction, four important criteria must be met: (1) ranges of relatively normal movements, without pain, with an interincisal distance of 40 mm, (2) good occlusion, (3) stable TMJ, and (4) facial and mandibular symmetry¹²,³⁶.

However, not all condylar fractures are managed by means of open reduction with internal fixation. Some authors considerate open reduction as a contraindication in head fractures, comminuted or not, due to the incidence of the high risk of avascular necrosis associated with loss of condylar function, resulting in the development of fibrous or osseous ankylosis³⁷,³⁸.

Nevertheless, some others decide to do surgical treatment based on their expertise and access to high technology. Minimally invasive techniques using endoscopes have been introduced to treat condylar mandible fractures and soft tissue surgery to offer advantages for selected cases such as preventing salivary fistulae, minimize blood loss and reduce the risk of facial nerve palsy or other neurologic complications¹⁵,³⁹,⁴⁰.

It is of great relevance to know the complications associated with the treatment of condylar fractures. In the transoperative period, hemorrhage may occur at the treated site, as well as an encounter of anatomical structures of relevance such as the VII cranial nerve or damage to one of its branches. Post-operative complications may include a greater number of complications associated with the approach and manipulation of the area such as infection, paraesthesia, salivary fistula or facial nerve paresis, auriculotemporal nerve dysfunction, Frey's syndrome, and scar resulting from the extraoral approach¹⁵,²²,⁴¹,⁴².