Conventional 2.0 mm miniplates versus 3-D plates in mandibular fractures.

AIM: To compare and evaluate the treatment outcome and postoperative complications in mandibular fractures using 2- and 3-dimensional miniplates.
MATERIALS AND METHODS: This study consisted of a sample of 28 patients (40 fracture sites) divided randomly but equally (single-blind control trial study) into two groups. Each group contains 14 patients (20 similar fracture sites in each group). Group 1 was treated with open reduction and internal fixation using 3-dimensional (3-D) miniplates. Group II was treated using 2-dimensional (2-D) 2-mm miniplates.
RESULTS: Out of 14 patients treated by conventional 2-mm miniplates, 2 patients developed occlusal discrepancy, another 2 had postoperative mobility at fracture site, and 1 developed plate failure and subsequent infection, which was treated by removal of the plate under antibiotic coverage. One patient treated by 3-dimensional plates had tooth damage. STATISTICAL ANALYSIS: Chi-square test.
CONCLUSION: The results of this study suggested that the treatment of mandibular fractures (symphysis, parasymphysis, and angle) with 3-dimensional plates provided 3-dimensional stability and carried low morbidity and infection rates. The only probable limitations of 3-dimensional plates were excessive implant material due to the extra vertical bars incorporated for countering the torque forces.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

There are two fundamentally different philosophies for the treatment of mandible fracture using plates and screws:

Concept of rigid fixation: Spiessl[1] introduced compression plates, which were fixed along the lower border of fractured mandible using bicortical screws. Compression plates rigidly fixed the fractured bone segments sufficiently to prevent inter-fragmentary movement and provide healing by primary intention. Difficulty in adaptation, bulk of the plates, scar formation due to extraoral approach, and increased chances of nerve injury were their disadvantages

Concept of semi-rigid fixation: Champy et al.,[2] defined the “ideal lines of osteosynthesis” based on experiments of GEBOAS (Group of Research in Bones and Joint Biomechanics of Strasbourg). Champy revolutionized intraoral fixation by innovating and modifying the Michelet et al.'s[3] technique of osteosynthesis. It consisted of mono-cortical, juxta alveolar, and subapical osteosynthesis without compression and intermaxillary fixation using miniaturized malleable plates. Small size of the plate, easy adaptability, easy placement, and use of intraoral approach led to increased use of mono-cortical plates in maxillofacial surgery.[4]

However, Luhr and AO/ASIF[5] advocates felt that miniplates did not offer adequate stabilization of the fractures, thereby necessitating the need of further inter-maxillary fixation. Farmand and Dupoirieux[6] presented 3-D plates with quadrangular shape formed by joining two mini-plates with interconnecting crossbars. Because of the quadrangular configuration of the plates, they provided good stability and resistance to torsional forces. Easy use, good resistance against torque forces, and compact form of the plates were some of their advantages.

Considering the above, this study was carried out to compare the conventional 2-mm miniplates and 3-D miniplates in terms of treatment outcome, stability, duration of surgery, and complications of treatment of mandible fractures.

MATERIALS AND METHODS

This was a prospective study consisting of a sample size of 28 patients (18 males and 10 females) with undisplaced as well as displaced mandible fractures conducted at Govt. Dental College and Hospital, Ahmedabad. Exclusion criteria for study were comminuted, malunited, and infected fractures as well as mandibular coronoid and condylar fractures. All patients were within the age group of 18-60 years, excluding medically compromised patients.

The patients were divided randomly (single-blind control trial study) into two groups of 20 patients each, but the number of patients of each type were divided equally. Group I was treated with open reduction and internal fixation (ORIF) using 3-D miniplates and Group II were treated with conventional 2-mm (2-D) stainless steel miniplates. Also, 2-mm, 4-hole with gap conventional 2-D and 6-hole with gap 3-D stainless steel miniplates were used. Three-dimensional designs were formed by joining two 2-D miniplates with interconnecting vertical crossbars. Then, 2 × 8 mm and 2 × 10 mm stainless steel self-tapping screws were used to fix the plates. The diameter of head of screw was 2.8 mm with countersinking of the head corresponding to the 30-degree beveled hole in the plate [Figure 1].

Figure 1

Conventional 2.0-mm S.S miniplates and 3-D S.S plates used in the mandible fracture

Reduction and fixation of fracture segments was done intraorally under GA, except in some inaccessible angle fractures where transbuccal approach was used. In Group I patients, fixation of the 3-D plates was done in the following manner: In the symphysis/parasymphysis region, the upper crossbar of 3-D plates was placed in subapical position of teeth, and injury to dental roots was avoided using mono-cortical screws. In the region posterior to mental foramen, 3-D plates was placed in such a way that upper cross bar was between root apex and inferior alveolar nerve. In the region of angle, 3-D plate was placed in such way that vertical strut was perpendicular to external oblique ridge. Here, we showed a preoperative and postoperative series of photographs and radiographs of right parasymphysis fracture fixed with 3-D plates [Figures 2–6].

Figure 2

Preoperative photograph of patient with right parasymphysis fracture showing deranged occlusion

Figure 6

Postoperative OPG showing reduction and fixation of right parasymphysis fracture with 2.0-mm, 6-hole, 3-D plates

Preoperative OPG show right parasymphysis fracture between right lateral incisior and canine with fracture line runs downward and backward

Intraoperative photograph of patient showing reduction and fixation of right parasymphysis fracture site using 2.0-mm, 6-hole, 3-D plates via intraoral degolving incision (Group 1)

Postoperative photograph of patient with right parasymphysis fracture showing perfect occlusion

In Group II patients, fixation of conventional 2-D miniplates was done along the osteosynthesis lines as described by Champy. Postoperative intermaxillary fixation was avoided and done only if required or when occlusion was deranged. Postoperative X-ray was taken to evaluate reduction and fixation of fracture. Here, we showed a preoperative and postoperative series of photographs and radiographs of right parasymphysis fracture fixed with 2-D plates [Figures 7–11].

Figure 7

Preoperative photograph of patient with right parasymphysis fracture between right lateral incisior and canine showing anterior and left-posterior open bite

Figure 11

Postoperative OPG shows reduction and fixation of right parasymphysis fracture with 2.0-mm miniplates, 4-hole with gap miniplates, and restoration of occlusion

Preoperative OPG show right parasymphysis fracture between right lateral incisior and canine with fracture line runs downward and forward

Intraoperative photograph of patient showing reduction and fixation of right parasymphysis fracture site with conventional 2.0-mm, 4-hole with gap miniplates placed along champy's line of osteosynthesis through intraoral degloving incision

Postoperative photograph of patient with right parasymphysis fracture showing perfect occlusion

RESULTS

Patients of both groups were evaluated for malunion, non-union, damage to root by screw, implant failure, infection at site, neurosensory deficit, occlusal discrepancy, and postoperative mobility at fracture site.

DISCUSSION

In our study, interpersonal violence accounted for 14.28% of the cases, fall injury accounts for 28.58% of cases of mandible fracture [Table 1] road traffic accidents were responsible for the majority of cases (57.14%) of mandible fractures. This is in accordance with the study by Bormann et al[7] [Table 1]. Out of 28 patients in our study, 18 were male (64.29%) and 10 (35.71%) were female Table 2. This male dominance was also reported by Haug et al.[8] The age group most commonly affected was 21-30 years (40%). Eight patients had bilateral mandible fracture and 12 had unilateral fracture. The most common site of mandible fracture was parasymphysis (35%) and angle (35%), followed by body (20%) and symphysis (10%) [Table 3, Graph 1].

Table 1

Pattern of etiology of fracture in the present study

Table 2

Gender distribution of patients

Table 3

Distribution of fracture site, favorability of fracture site, methods of fixation of fracture site

Graph 1

(a, b) Distribution of fracture site, favorability of fracture site, and methods of fixation of fracture site

Among patients in Group II, in 1 patient, there was intraoral exposure of plate and intraoral pus discharge at left lower-third molar region. X-ray OPG of patient shows fractured 2-D miniplate at the left angle [Figure 12]. This complication was treated by removal of implant, intraorally under higher antibiotic coverage. No incidence of plate failure was reported in Group I patients, which coincides with the report by Guimond et al.,[9] on fixation of mandible angle fracture with 3-D plates [Table 4]. Fracture of mandibular angle is associated with highest incidence of postsurgical infection of all mandible fractures reported by Lizuka and Lindquist.[1011]

Figure 12

X-ray OPG shows fractured 2.0-mm conventional plate at left angle

Table 4

Comparsion of complication between group I and group II

In the angle region where horizontal and vertical rami of mandible meet and where powerful elevator muscles are attached to the ramus, strong distractive forces are created; therefore, to counteract these forces, a strong fixation device is required. In this study, the advantage of 3-D plating system over conventional 2-D miniplates comes from the fact that the screws of the 3-D plates are placed in the box configuration on both sides of the fracture rather than on a single line. Also, a broad platform is created that may increase the resistance to the torsional forces along the axis of the plate. This theory coincides with the study of Alkan et al.[12]

One case of tooth damage at the symphysis region was reported among Group I patients. Vitality testing of the injured tooth was done. Endodontic treatment was carried out for the management of injured tooth. The damage occurred due to the larger size of 3-D plate and insufficient vertical height of anterior mandible. Advantage of conventional 2-D miniplates over 3-D miniplates is their small size and easy adaptability, which minimizes the chances of tooth damage [Table 4].

The occlusion of patients was checked preoperatively and during the follow-up stages after surgery. Among Group II, 2 patients (both displaced parasymphysis + angle fractures) developed postoperative occlusal discrepancy, which was corrected by postoperative inter-maxillary fixation for 4 weeks. None of the patients of Group I developed occlusal discrepancy [Table 4]. According to Champy, when only one linear conventional plate is applied at the external oblique ridge in cases of mandibular angle fracture, torsional and bending forces usually cause movement along the axis of the plate with bucco-lingual splaying and gap formation at the inferior border, respectively. This coincides with the study of Gutwald et al.,[13] on angle fracture using various fixation devices. Also, 3-D plates, because of a box-like configuration, provide rigid fixation of fractures that prevent bucco-lingual splaying and gap formation at the fracture site and subsequent occlusal discrepancy; this is the advantage of 3-D miniplates over 2-D miniplates.

Mobility of fractured segments was evaluated in both groups: In Group II, 2 patients (one symphysis and other angle + parasymphysis fracture) had immediate postoperative mobility present at the fracture site, which was corrected by postoperative inter-maxillary fixation for 4 weeks. In Group I, none of patients had immediate postoperative mobility present at the fracture site [Table 4]. According to Andrew et al., as 3-D plates are square or rectangular units, they provide increased torsional stability. Also, as the symphysis fractures are under greater degree of torsional strain than any other area of the mandible, 3-D plates provide higher stability in this region.

Duration of surgery was measured from incision to closure of wound. The operating time required for the placement of 3-D plates in the angle region was 20-min extra as compared to intraoral placement of single conventional 2-D miniplate. This finding coincides with the study of Feledy et al.,[14] who conducted a study on the time taken for the treatment of angle fractures. In the body region, difference was not significant, average time of 7 min more was taken by 3-D plates; whereas, in the symphysis and parasymphysis region, 20 min more was taken for 3-D plate fixation than for 2-D miniplates.

In our study, not a single patient treated by 3-D plate developed infection or plate failure, which is not in accordance with Zix et al.,[15] who reported 1 patient with fractured 3-D plate that occurred due to reduced inter-fragmentary cross-sectional bone surrounding the fracture site after extraction of molar tooth in angle region, leading to higher torsional forces. Also, an infection rate of 6.6% was reported by Parmar et al.[16] Implant failure (4.54%) and postoperative neurosensory deficit (4.54%) was recorded by Goyal et al.[17] Fixation of mandibular angle fractures with single conventional miniplates at the upper border is associated with complications like infection, malocclusion, and mobility of fracture segments, as studied by Singh et al.[18] Parallel reports has been found in literature in several type of clinical situation.[1920]

CONCLUSION

The 3-D plating system has advantages over conventional 2-D miniplates. Quadrangle geometry of plate assures a 3-D stability of fracture sites as it offers good resistance against torque forces, thereby avoiding the need for inter-maxillary fixation, ensuring early restoration of mandibular function, and reduced rate of infection at fracture site postoperatively. Simplicity, malleability, low profile, ease of application, and reduced infection rate are its advantages over conventional 2-D miniplates.

Based on the above, it can be concluded that, to minimize the rate of postoperative complications, for fractures of symphysis, displaced parasymphysis and angle and bilateral mandible fractures, 3-D plates could be a better option than conventional 2-mm miniplates. The small sample size and limited follow-up could be considered as the limitations of this study.