1.1

Anatomy and classification of fractures

The mandibular condyle is subdivided into three areas: the condylar head, neck, and subcondylar region [ , ] ( Fig. 1 ). The mandibular head has a rounded structure that articulates with the glenoid fossa and is surrounded by a temporomandibular joint capsule ( Fig. 2 ). Just below the TMJ capsule, the condyle tapers towards the condylar neck region and widens again for its attachment to the mandible, a region that is called the subcondylar area [ ]. The condyle of the mandible functions as a joint with the TMJ capsule.

AOCMF condylar fracture classification system. (A) sagittal view; (B) posterior view .

Muscles of mastication [ ].

The TMJ functions as a joint with the ability to open, close, protrude, retrude, and travel to the left and right. The lateral and medial pterygoid muscles are involved in the lateral movement of the mandible [ , ]. In this study, fracture displacement was defined as the relationship between the caudal end of the condyle and the mandibular ramus. Displacement can occur depending on the degree of angulation of the fractured bones and their overlap. Dislocation is related to the location of the mandibular head relative to the glenoid foramen. The term intracapsular refers to fractures of the mandibular head surrounded by the TMJ capsule [ , ].

As for classification systems for condylar fractures, in 1977 Lindahl presented the levels, displacement and condylar dislocation ( Fig. 3 ) [ , , ] In 2005, Loukota et al. presented a system adopted by SORG (Strasbourg Osteosynthesis Research Group) that defined condylar areas using the ‘A line’, which defines the demarcation between the neck and the subcondylar area. It is a horizontal line tangential to the deepest part of the sigmoid notch and perpendicular to a vertical line parallel to the posterior edge of the mandibular ramus ( Fig. 4 ). Fractures of the condylar neck were above line A, whereas those below line A were classified as subcondylar fractures [ ].

Lindahl classification of condylar fractures [ ].

SOGR/Loukota classification of condylar fractures. (A) Condylar head fracture, (B) condylar neck fracture, and (C) subcondylar fracture [ ].

In 2014, the AOCMF published a classification system, such as the Loukota system ( Fig. 1 ), with a similar demarcation of fractures. The angulation and displacement of the condylar segments were similar to those of the Lindahl system [ ].

1.2

Decision-making regarding treatment

Condylar fractures need to be analysed on an individual basis to decide the treatment of choice, with the aim of restoring function as soon as possible. To make this decision, the following points must be assessed: (A) mouth opening, with or without pain, and the size of the interincisal opening, (B) mandibular movement in all excursions and opening deviations, (C) occlusion, (D) prevention of TMJ dysfunction, and (E) facial and mandibular symmetry [ ].

In the closed treatment of condylar fractures, there are two treatment possibilities:

• (1)

  a mild diet for 1–2 months, use of analgesic medication, and mandibular mobility exercises.

• (2)

  Rigid maxillomandibular locking for 3 weeks or locking with elastic bands using bars or screws to guide and limit mandibular movement, which can normally be used for 4–6 weeks or up to 3 months [ ].

Physiotherapy introduced at the right time is crucial to prevent the formation of scar tissue, re-establish muscle strength, and prevent chronic pain [ , ]. Physiotherapy is possible when there is no or minimal displacement and no shortening of the ramus or dislocation. It has also been observed that in fracture segments with displacement and dislocation, even after a period of maxillomandibular blockade, the patient may develop normal occlusion and adequate excursive movement, but the mandibular segment may remain in a non-anatomical position [ ].

The strong indications for open surgical treatment for the reduction and fixation of condylar fractures have been supported by several systematic reviews and randomised clinical trials published over the last 25 years [ ]. The literature shows rare and absolute indications in clinical situations, such as dislocation of the middle cranial fossa of the proximal condylar segment and foreign bodies inside the TMJ. Strong evidence for open surgical treatment includes inability to establish satisfactory occlusion, bilateral condylar fractures, displacement and angulation of the condylar fragment >45°, condylar fracture in edentulous patients, shortening of the mandibular ramus height equal to or greater than 2 cm and associated midface fractures [ , , , ].

Condylar fractures in paediatric patients require greater attention and caution when defining the treatment. The mandibular condyle is the growth centre of the mandible with significant potential for remodelling in childhood [ ]. The mandibular condyle in children is highly vascularised with great osteogenic capacity due to its periosteal coverage, which can generate a greater risk of TMJ ankylosis as a complication of fracture. 3] For this reason, in closed treatments, the duration of the maxillomandibular block should be shorter than that in adults because of the increased risk of condylar ankylosis. There is a large consensus in the literature that children up to 8 years of age should not undergo open reduction of condylar fractures only in extremely necessary cases [ , ]. these patients should be followed-up over the long term to monitor the development of malocclusion, TMJ derangements, and possible TMJ disorders [ ].

2.1

Pre-auricular

This approach allows adequate access to the condylar head and neck; however, subcondylar fractures are more challenging to reduce using this approach. An incision was made in the natural fold of the skin in the pre-auricular region, extending from the

Helical border to the temporal scalp, as required. The subcutaneous fat and temporoparietal fascia were incised and dissection was performed up to the superficial layer of the deep temporal fascia, which was incised up to the root of the zygomatic arch, thus protecting the temporal branch of the facial nerve. The joint capsule is opened to expose the condylar neck [ , ].

2.2

Retromandibular

This access requires dissection through the parotid gland (transparotid gland) or posterior to the gland (retroparotid gland). In this approach, the retromandibular vein can be found and must be retracted away from the field [ , ]. The transparotid retromandibular approach is performed behind the posterior border of the ramus, a few millimetres below the earlobe, and approximately 3 cm inferior. This incision was made through the skin and subcutaneous tissue, reaching the superficial musculoaponeurotic system. Through blunt dissection, the parotid capsule was opened parallel to the branches of the facial nerve, thus reaching the masseter muscle, which must be incised, followed by subperiosteal dissection of the fracture [ , , ].

A retroparotid approach was used from the tip of the mastoid to the mandibular angle. Through an inferior approach, the parotid gland is located in the tail region, where it overlaps with the sternocleidomastoid muscle. To expose the masseter muscle lifts used to lift the gland, dissection of the masseter muscle was performed in the same manner as in the transparotid approach.

2.3

Submandibular incision

A submandibular or Risdon incision is normally used in combination with other approaches to treat condylar fractures and to reduce distal fragments. A skin incision was made 2 cm below the lower border of the mandible and was about 4–5 cm long. This incision is made as far as the plastinum, where the marginal mandibular nerve runs deep into the fascia of the submandibular gland and requires ligation of the anterior facial vein at the lower edge of the submandibular gland. The masseter muscle is incised through the elevation of the soft tissue flap, and subperiosteal dissection continues up to the level of the fracture [ , , ].

2.4

Rhytidoplasty/facelift

This surgical approach is similar to that of a transparotid retromandibular incision. A pre-auricular incision is made, which must be brought around the lobe, to the auricular skin and to the temporal hairline. The skin flap was made through a wider elevation to expose the superficial musculoaponeurotic system. The parotid capsule was closed to prevent salivary fistulas or sialoceles. The masseter muscle and superficial musculoaponeurotic system were then closed using resorbable sutures [ ].

2.5

Retroauricular incision

The incision was made 3–5 cm vertically in the retroauricular region, approximately 1.5 cm down to the medial sulcus, through the skin and subcutaneous tissue. The anterior and posterior flaps were elevated to incise the muscle and fat of the perichondrium and mastoid fascia, allowing direct visualisation of the concha. A second incision was made through the anterior wall of the ear canal in a wide portion to avoid stenosis [ ].

At this depth, retraction of the external ear allows the retromandibular space to be exposed, and in blunt dissection of the parotid gland, the retromandibular vein is usually found and must be ligated. Due to the posterior access, the facial nerve (frontal branch) and auriculotemporal nerve are localised and gently protected by a retracted flap superficial to the retromandibular vein. When the ramus and head of the mandible were reached, the periosteum was incised and displaced, showing fragments of the condylar fractures [ ].

The parotid capsule was closed with a slow-resorption suture to avoid a salivary fistula, and the auricular canal was reconstructed with a simple slow-resorption suture to avoid stenosis. The tissue planes were closed using a resorbable, interrupted suture. A gauze with petrolatum was inserted into the external acoustic meatus for 15 days, with a compressive bandage for 10 days. In the postoperative period, the wound was kept moist twice a day for a week with hydrogen peroxide and antibiotic ointment, and the ear was checked daily to avoid complications such as infection, haematoma, and stenosis [ ].