Management of paediatric mandibular condylar fractures with screw-based semi-rigid intermaxillary fixation

Abstract

This study was designed to evaluate the feasibility and safety of screw-based semi-rigid intermaxillary fixation (IMF) combined with a specially designed occlusal splint in the conservative treatment of paediatric mandibular condylar fractures. Thirteen paediatric patients with 20 sides of condylar fractures treated with semi-rigid IMF were analyzed retrospectively. Semi-rigid IMF was achieved by inserting self-drilling IMF screws into the anterior alveolar bone of the maxilla and mandible suspended with elastic bands. An occlusal splint with a molar fulcrum was used for functional repositioning of the condylar fragment. After 4 weeks, the screws and occlusal splint were removed. During a mean period of 28.6 months’ follow-up, the patients’ maximal mouth opening increased to a mean of 37.69 mm. Clinical and radiological examinations revealed satisfactory results in facial symmetry and condylar remodelling. No clinical symptoms or radiographic evidence showed dental injuries associated with screw insertion. This study suggests that this method might be a safe, easy, and effective management of paediatric condylar fractures.

The management of mandibular condylar fractures in children is different from that in adults because of mandible growth and mixed dentition . Conservative/functional treatment is recommended as the first choice for paediatric condylar fracture, because of the high capacity for fracture remodelling .

Badly managed paediatric mandibular condylar fractures may lead to severe complications, such as temporomandibular joint (TMJ) ankylosis, facial asymmetry, TMJ disorders (TMDs), malocclusion, and chronic facial pain .

Temporary intermaxillary fixation (IMF) is widely used for the functional treatment of paediatric mandibular condylar fractures. The IMF is applied for a short period followed by guiding elastic , which is used to guide the mandible into central occlusion . The most common methods are arch bars and eyelet wires . These techniques are associated with some intrinsic disadvantages: poor patient tolerability; length of time required ; difficult removal; damage to the teeth and the periodontal tissues ; possibility of needlestick injuries and diseases transmission . Oral hygiene is difficult to maintain , which may exacerbate the prevalence of dental caries.

Other methods, such as orthodontic brackets and vacuum-formed splint, use the teeth as the anchors to apply IMF . Clinically it is difficult to apply these methods to paediatric patients because of the nature of the mixed dentition, including absence of teeth, unstable deciduous teeth, and the unfavourable shapes of the teeth for bonding with orthodontic brackets or vacuum-formed splints. The orthodontic elastic traction applied to the teeth might lead to teeth extrusion and occlusal disturbance. To overcome these problems, a screw-based semi-rigid IMF with an occlusal splint was employed for functional treatment of condylar fractures in children. The clinical and radiological results were analyzed retrospectively.

Materials and methods

Paediatric patients (age < 12 years) with isolated displaced/dislocated condylar fractures (S piessl & S chroll classification , type II, III, IV, V and VI) were involved in this research. Patients with a restricted preoperative mouth opening less than 15 mm were excluded because of the difficulty in obtaining an occlusal impression.

From 2005 to 2008, 13 patients (11 boys, 2 girls) with 20 condylar fractures were treated in the authors’ hospital. The parents of the children had given informed consent. The mean age of the patients was 6.85 years (range 3.5–11 years). Six of them suffered unilateral condylar fracture and the others were bilateral cases. Preoperative panoramic radiographs and spiral computed tomography (CT) or cone-beam CT (CBCT; New Tom VG, Italy; scan parameters: slice thickness 0.24 mm, scan time 5.4 s, 110 kV, 15 mA) was performed on each patient to classify the fractures. Ten patients had type VI condylar fracture and the others had type III and type V fractures. Patient data is given in Table 1 .

Table 1
Patient characteristics and MMO at different stages of treatment.
Patients number Gender Age (years) Fracture sides Classification of fracture Follow-up period (months) MMO (mm)
pre/post/fol
1 Male 4.5 Left VI 51 20/33/46
2 Male 7 Bilateral VI 49 25/36/38
3 Male 5 Left VI 41 15/25/36
4 Male 7 Left VI 39 18/28/39
5 Male 6 Right III 32 20/40/43
6 Male 7 Right VI 32 20/37/38
7 Male 6 Bilateral VI 29 15/20/38
8 Male 6 Bilateral VI 28 15/15/25
9 Male 6 Bilateral VI 24 15/32/38
10 Female 10 Left V 16 20/32/38
11 Male 10 Bilateral VI 14 15/21/40
12 Male 3.5 Bilateral VI 9 15/32/36
13 Female 11 Bilateral VI 8 15/30/35

pre/post/fol, pre-operative/post-operative/follow-up.
Fractures were classified according to S piessl & S chroll . Type I: fracture without displacement. Type II: low fracture with displacement. Type III: high fracture with displacement. Type IV: low fracture with dislocation. Type V: high fracture with dislocation. Type VI: intracapsular fracture.

IMF was achieved by self-drilling cortical bone screws. The titanium screws (Zhongbang Titanium Biomaterials Corporation, Xi’an, P.R. China) were 2 mm in diameter and either 9 mm (for upper jaw) or 11 mm (for lower jaw) in total length. The 9 mm screw has a 5 mm thread length and the 11 mm screw a 7 mm thread length ( Fig. 1 A ).

Fig. 1
(A) Self-drilling IMF screws. (B) Lateral view of the occlusal splint with a molar fulcrum made of acrylic resin. (C) Intraoral view of the semi-rigid IMF with the occlusal splint in a 5-year old patient with left condylar fracture (patient no. 3). Black arrow: the molar fulcrum.

In practice each screw was usually inserted transmucosally between the canine (deciduous or permanent) and the first pre-molar or deciduous first molar in all four quadrants ( Fig. 2 A ). The screws were inserted manually into the alveolar bone at the junction of the attached and unattached gingivae under general anaesthesia. To avoid potential damage to the adjacent dental roots or germs, preoperative radiographs were analyzed carefully before screw insertion.

Fig. 2
(A) Panoramic image of screw insertion (arrows) of patient no. 3. A left condylar head fracture was presented (circle). (B) Panoramic radiograph performed at 41 month follow-up. Arrows indicated the site of insertion of the previous screws. A normal anatomical relationship of the left joint was presented (circle).

A specially designed vacuum-formed occlusal splint was used for functional repositioning of the displaced condylar fragment. A 3 mm thick molar fulcrum for the splint was formed with self-curing acrylic resin at the fractured side ( Fig. 1 B). In bilateral cases, both sides of the splint were thickened equally. The splint was fitted to the upper arch and the screws were suspended with elastic bands to achieve semi-rigid IMF on the second day after screw insertion ( Fig. 1 C).

The semi-rigid IMF was routinely kept in place for 4 weeks. Patients were able to eat a soft diet. Postoperative antibiotics were administered for 3 days. The patients were advised to gargle after meals to maintain oral health throughout the treatment period. If screw loosening occurred, the screw was re-inserted.

After 4 weeks, the splint and screws were removed. The patients were asked to practice active mouth-opening exercises. Follow-up examinations were carried out including routine physical and radiographic examinations at 3, 6, 12, 24 months, and more. The maximal mouth opening (MMO) was measured. Symptoms of TMDs were checked including joint pain, clicking, and deviation of the mandible. A deviation of 3 mm or more of the mandibular midline during opening was considered aberrant . The malocclusion was assessed as unacceptable clinical function.

The method for evaluating facial symmetry described by T horen et al. was applied. A difference of 3 mm or more in ramus height amongst unilateral cases or an angulation of 3° or more in mandibular midline related to the facial midline amongst bilateral cases was considered asymmetry, respectively. Remodelling of the condyle was evaluated with CT according to T horen et al.’s classification .

The teeth adjacent to the screws were examined for vitality. The mobility and abnormal eruption of the permanent teeth were tested and the possible root/germ injuries were checked with panoramic radiographs. Other related complications caused by the screws (mucosa coverage, local inflammation) and material failure (screw loosening, breakage) were recorded.

For all statistical analysis, the SPSS software programme (except ‘program’ in computers) version 14.0 was used and the data were compiled as mean ± standard deviation (SD).

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Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Management of paediatric mandibular condylar fractures with screw-based semi-rigid intermaxillary fixation
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