Int. J. Oral Maxillofac. Surg. 2014; 43: 708–716 http://dx.doi.org/10.1016/j.ijom.2014.02.002, available online at http://www.sciencedirect.com
Systematic Review Trauma
Three-dimensional versus standard miniplate fixation in the management of mandibular angle fractures: a systematic review and meta-analysis
` . Al-Moraissi1,2, E. A T. M. El-Sharkawy1, T. I. El-Ghareeb1, B. R. Chrcanovic3 1 Department of Oral and Maxillofacial Surgery, Faculty of Oral and Dental Medicine, Cairo University, Egypt; 2Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Thamar University, Yemen; 3Department of Prosthodontics, Faculty of Odontology, Malmo¨ University, Sweden
E. A`. Al-Moraissi, T. M. El-Sharkawy, T. I. El-Ghareeb, B. R. Chrcanovic: Threedimensional versus standard miniplate fixation in the management of mandibular angle fractures: a systematic review and meta-analysis. Int. J. Oral Maxillofac. Surg. 2014; 43: 708–716. # 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. The aim of the present study was to test whether there is a significant difference in the clinical outcomes between standard and three-dimensional (3D) miniplate fixation in the management of mandibular angle fractures (MAFs). An electronic search without date and language restrictions was performed in October 2013. Inclusion criteria were studies in humans including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. Six studies were included. The meta-analyses revealed statistically significant differences for the incidence of hardware failure and postoperative trismus. There were no significant differences in the incidence of postoperative infection, malocclusion, wound dehiscence, non-union/malunion, or paresthesia. The cumulative odds ratio was 0.42, meaning that the use of 3D miniplates in the fixation of MAFs decreases the risk of the event (postoperative complication) by 58%. The results of this meta-analysis showed lower postoperative complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs.
Approximately 19–40% of all facial fractures are fractures of the mandible, and 12–30% of all mandibular fractures (MFs) are fractures of the mandibular angle.1–5 Among MFs, the angle is the first most frequent region for fractures caused by sports activities, the second most frequent 0901-5027/060708 + 09 $36.00/0
region for fractures caused by violence, and the third most fractured region in cases of traffic accidents involving automobiles.5 Although there is widespread agreement regarding the need for surgical reduction and fixation of a mandibular angle fracture (MAF), a variety of differ-
Key words: mandibular angle fracture; surgical treatment; rigid fixation; conventional miniplate; 3D miniplate; complications. Accepted for publication 10 February 2014 Available online 15 March 2014
ent treatment modalities have been described.6,7 The so-called ‘Champy technique’ has probably been the most commonly used method of fixation to date. The biomechanical studies of Champy et al.8 resulted in the concept of an ideal line of osteosynthesis.
# 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
3D vs. standard miniplate meta-analysis They used blocks made of a photoelastic resin to represent the mandible. A plate was then secured to the lateral surface of the blocks along the superior border, and the complex was subjected to simple cantilever loading. The test showed that the pattern of stress distribution created in the plated blocks was similar to the uncut blocks. This study was instrumental in establishing the concept of tension band plating for the treatment of MFs. Taking into account torsional tensile and compressive forces at all points of the mandible, the ideal lines of osteosynthesis were described, and this formed the basis of the internal fixation of MFs with miniplates. In the case of MAFs, results have demonstrated that the best site for plating is the vestibular osseous flat part located in the third molar region, which will counteract the muscular forces that act naturally to distract the fragments. It has also been suggested that an osteosynthesis located lower down, on the outer surface of the mandible, is solid enough to support the strain resulting from the masticatory forces in this region. However, the stability of the single miniplate fixation of MAFs has been challenged in several biomechanical studies.7 The use of three-dimensional (3D) strut plates has been one of the methods of fixation to challenge the Champy technique for the fixation of MAFs, with a growing number of clinical studies.6 The 3D plates can be considered a two-plate system, with two miniplates joined by interconnecting crossbars.9 Their shape is based on the principle of the quadrilateral as a geometrically stable configuration for support.10 Because the screws are arranged in the configuration of a box on both sides of the fracture, a broad-band platform is created, increasing the resistance to twisting and bending of the long axis of the Plate.11 There is a simultaneous stabilization of the tension and compression zones, making 3D plates a time-saving alternative to conventional miniplates. Moreover, this system is simple to apply because of its malleability, low profile (reduced palpability), and ease of application (requires little or no additional contouring).11 As philosophies on the treatment of maxillofacial trauma alter over time, a periodic review of the different concepts is necessary to refine techniques and eliminate unnecessary procedures. This would form the basis for optimum treatment. Thus, the objective of this study was to address the focused question ‘Is there a significant difference in the clinical outcomes between standard and 3D miniplate
fixation in the management of MAFs?’ by conducting a systematic review and metaanalysis of prospective studies published in the dental literature up to and including October 2013. Materials and methods Data sources and key words
An electronic search without date or language restrictions was performed in the following databases: PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, Medline, Alt HealthWatch, Health Source: Consumer Edition, Health Source: Nursing/Academic Edition, CINAH, SPORTDiscus, and Electronic Journal Centre. The key words and combinations of these used in the search included: ‘conventional AND versus AND 3-dimensional AND miniplate AND management AND mandibular angle AND fracture,’ ‘standard miniplate versus AND 3-dimensional AND fixation AND mandibular angle AND fracture,’ ‘Champy technique versus 3-dimensional miniplate AND fixation AND mandibular angle AND fracture,’ ‘mandibular angle,’ ‘miniplate,’ ‘threedimensional,’ ‘standard or conventional,’ ‘rigid fixation,’ ‘osteosynthesis,’ ‘grid miniplate,’ ‘matrix miniplate,’ ‘3D strut miniplate,’ and ‘Champy.’ A manual search of oral and maxillofacial surgery-related journals, including the International Journal of Oral and Maxillofacial Surgery, British Journal of Oral and Maxillofacial Surgery, Journal of Oral and Maxillofacial Surgery, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, Journal of CranioMaxillofacial Surgery, Journal of Craniofacial Surgery, and Journal of Maxillofacial and Oral Surgery, was also performed. Relevant reviews on the subject and the reference lists of the studies identified were also scanned for possible additional studies. Moreover, online databases providing information on clinical trials in progress were checked (http://clinicaltrials.gov; http://www.centerwatch.com/ clinical-trials; http://www.clinicalconnection.com).
Inclusion and exclusion criteria
Inclusion criteria were studies in humans including randomized or quasi randomized controlled trials (RCTs), controlled clinical trials (CCTs), and retrospective studies with the aim of comparing 3D and standard miniplate fixation techniques
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in the management of MAFs, and reporting the incidence of postoperative complications. Exclusion criteria were: (1) case reports, technical reports, animal studies, in vitro studies, and review papers, (2) studies including infected comminuted MAFs, and (3) studies including angle fractures in atrophic edentulous mandibles. Selection of relevant studies
The four authors independently assessed the eligibility of all studies retrieved from the databases. Disagreements concerning the selected studies were resolved by discussion. The following data were extracted (when available) from the studies included in the final analysis: year of publication, study design, number of patients, patient age range and/or mean age, follow-up period, number of MFs, region of MFs, fixation methods, surgical approach, length of operation, postoperative maxillomandibular fixation (MMF), use of antibiotics and/or chlorhexidine, number of teeth retained and removed, mouth opening, postoperative radiological assessment, and postoperative complications (infection, postoperative occlusion, hardware failure, segmental mobility, malunion, non-union, wound dehiscence, inferior alveolar nerve paresthesia, unstable fracture fragments). Authors were contacted for possible missing data. Quality assessment
A methodological quality rating was performed by combining the proposed criteria of the MOOSE statement,12 STROBE statement,13 and PRISMA,14 in order to verify the strength of scientific evidence in clinical decision-making. The classification of the risk of potential bias for each study was based on the following five criteria: random selection in the population, definition of inclusion/ exclusion criteria, report of losses to follow-up, validated measurements, and statistical analysis. A study that included all the criteria mentioned above was classified as having a low risk of bias, a study that did not include one of these criteria was classified as having a moderate risk of bias. When two or more criteria were missing, the study was considered to have a high risk of bias. Meta-analysis
Meta-analyses were conducted only if there were studies of similar comparisons
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reporting the same outcome measures. For binary outcomes, we planned to calculate a standard estimation of the odds ratio (OR) by random-effects model if heterogeneity was detected, otherwise a fixedeffect models with a 95% confidence interval (CI) was performed. Weighted mean differences were used to construct forest plots of continuous data. The data were analysed using the statistical software Review Manager (version 5.2.6; The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark, 2012). Assessment of heterogeneity
The significance of any discrepancies in the estimates of the treatment effects of the different trials was assessed by means of Cochran’s test for heterogeneity and the I2 statistic, which describes the percentage total variation across studies that is due to heterogeneity rather than chance. Heterogeneity was considered statistically significant if P < 0.1. A rough guide to the interpretation of I2 given in the Cochrane Handbook15 is as follows: (1) from 0% to 40% the heterogeneity might not be important, (2) from 30% to 60% may represent moderate heterogeneity, (3) from 50% to 90% may represent substantial heterogeneity, and (4) from 75% to 100% there is considerable heterogeneity. Investigation of publication bias
A funnel plot (plot of effect size versus standard error) was drawn. Asymmetry of a funnel plot may indicate publication bias and other biases related to sample size, although the asymmetry may also represent a true relationship between trial size and effect size. Sensitivity analysis
If there were sufficient studies included, we planned to conduct a sensitivity analysis to assess the robustness of the review results by repeating the analysis with the following adjustment: exclusion of studies with a high risk of bias. Results Literature search
The study selection process is summarized in Fig. 1. The electronic search resulted in 702 entries. Six additional articles were identified by hand-searching. After the initial screening of titles and abstracts, 382 articles were excluded due
Fig. 1. Study screening process.
to duplication. Of the remaining 326 studies, 292 were excluded for not being related to the topic. The full-text reports of the remaining 34 articles were assessed, leading to the exclusion of 28 because they did not meet the inclusion criteria. Thus, a total of six publications were included in the review. Description of studies included
Detailed data of the six studies included are listed in Table 1. Three RCTs10,16,17 and three retrospective studies18–20 were included in the meta-analysis. In total, 307 patients were enrolled in the six studies, with 196 patients (197 MAFs) in the 3D miniplates group and 111 patients (112 MAFs) in the standard miniplate group. The maximum follow-up period varied between 3 and 12 months. The length of the follow-up period was not reported in one study,20 probably because it was a retrospective review of patient charts. All studies reported patients with additional MFs. Concerning the standard miniplate group, five of the six studies performed the fixation using only a single miniplate. In four studies10,17,18,20 the MAFs were fixed at the external oblique line and in one study16 at the external oblique line or on the lateral cortex, and one study19 used one or two miniplates, but two miniplates (superior tension band miniplate and inferior border miniplate) were used in most of the patients. Four studies10,16,17,19 used four-hole standard miniplates, whereas one study18 used six-hole miniplates and one study20 used four- or six-hole miniplates. Concerning the 3D miniplate group, a rectangular 3D miniplate was used in three
studies,10,16,18 whereas a curved 3D miniplate was used in the other three.17,19,20 The number of holes in the 3D miniplates used varied widely between the studies. Four studies used a combination of intraoral approach with the use of a transbuccal trocar.10,16,19,20 Two studies exclusively used the intraoral approach without a transbuccal trocar.17,18 Four studies16–19 provided information on the mean operation time. Quality assessment
Each trial was assessed for risk of bias; the scores are summarized in Table 2. One study was judged to be at high risk of bias,20 two were considered at moderate risk,18,19 and three were considered at low risk of bias.10,16,17 Effect of intervention
The forest plots for the effect of intervention are shown in Fig. 2. Infection
Data on postoperative infection were given in all studies (309 fractures). The cumulative analysis revealed an advantage for the 3D miniplate group regarding infection (fixed: OR 0.48, 95% CI 0.19– 1.22), but this advantage did not reach statistical significance (P = 0.12). The test of heterogeneity resulted in x2 = 2.61, df = 5, with P = 0.76, indicating homogeneity of studies. Malocclusion
Five studies (203 fractures) evaluated malocclusion, but with inconsistent follow-up
Table 1. Studies comparing three-dimensional and standard miniplate fixation techniques in the management of mandibular angle fractures.
Authors
Patient age range Study Patients (mean), years Follow-up Published design (n)
Region MFs of MFs
MAF fixation methods
Surgical approach
RA
60
15–73 (31.1)
7 days 14 days 28 days 3 months 6 months 12 months
90
Angle (n = 60), bodyb (n = 25), ascending ramusb (n = 5)
(G1) Single 2.0-mm Intraoral 6-hole miniplate at the external oblique line (n = 30) (G2) Single rectangular 2.0-mm 4-hole 3D miniplate (n = 30)
Singh et al.16,a
2012
RCT
50
17–46 (30.4)
1 week 4 weeks 8 weeks 12 weeks
56
Angle (n = 20), parasymphysis (n = 35), symphysis (n = 1)
Guy et al.19
2013
RA
90
14–58 (28)
8–308 days 161 (mean 47; G1) 2–355 days (mean 55; G2)
(G1) Single 2.0-mm 4-hole miniplate at the external oblique line or on the lateral cortex (n = 10) (G2) Single rectangular 2.0-mm 6-hole 3D miniplate (n = 10) (G1) One or two 2.0-mm 4-hole miniplate (n = 22)c (G2) Single curved 2.0-mm 8-hole 3D miniplate (n = 68)
Moore et al.20
2013
RA
104
NM (31)
NM
168
Angle (n = 96), parasymphysis (n = 41), body (n = 11), condyle (n = 5), coronoid (n = 2), ramus (n = 6) Angle (n = 106), parasymphysis (n = 11), body (n = 51)
Teeth retained/ removed (in MFs)
89 (G1) 81 (G2)
NP
4/NM
Intraoral or intraoral + transbuccal
44 (G1) 57 (G2)
17 (G1) 8 (G2)
5/NM
Intraoral + transbuccal (G1, G2), extraoral (9% in G1)
232 (G1) 219 (G2)
14; 64% (G1) 35; 51% (G2)
7/preoperative and operative
NM
NM
NP
‘Post-operative’/ NM
NM
(G1) Single 2.0-mm Intraoral + transbuccal 4- or 6-hole miniplate at the external oblique line (n = 33) (G2) Single curved 2.0-mm 8-hole 3D miniplate (n = 73)
‘Third molars were not removed during surgical intervention unless they were also fractured, luxated or they prevented an appropriate reduction.’ ‘Extraction of teeth in the line of fracture was performed if indicated’
3D vs. standard miniplate meta-analysis
Ho¨fer 2012 et al.18,a
Antibiotics/ Length of Postoperation, operative chlorhexidine, min, mean MMF (n) days
711
3 (G1) 1 (G2)
5–7/‘0.1%, from the time of presentation’
19/1
42 (G1) 102 (G2)
NP
5–7 days/‘ provided to all patients’
0/7
NM, not mentioned; NP, not performed; RCT, controlled clinical trial; RA, retrospective analysis; MF, mandibular fracture; MAF, mandibular angle fracture; G1, group 1 (standard miniplates); G2, group 2 (3D miniplates); MMF, maxillomandibular fixation. a Personal communication was performed with one of the authors in order to obtain some missing data. b Mandibular fracture regions not being compared with the two different fixation types (conventional miniplates versus 3D miniplates). c Guy et al.19 divided their patients into strut plate and non-strut plate groups, with 68 and 22 patients, respectively. For the 22 patients in the non-strut group, the mandibular fractures of one patient were fixed with one miniplate at the external oblique line, and the mandibular fractures of 16 patients were fixed with two miniplates (superior tension band miniplate and inferior border miniplate), giving a total of 17 patients in whom miniplates were used. d A total of 18 patients were included in this study, however five were excluded postoperatively due to complex fractures resulting in postoperative MMF.
Al-Moraissi et al.
NM
Region MFs of MFs Vineeth et al.10
2013
RCT
20
19–51 (NM)
1 1 1 3
day week month months
29
Angle (n = 20), additional fracturesb (n = 9; G1, n = 5; G2, n = 4) Xue et al.17
2013
RCT
13 (18)d
NM (NM)
1–2 weeks 4–6 weeks 6 months
22
Angle (n = 13), parasymphysis (n = 8), subcondylar (n = 1)
(G1) Single 2.0-mm Intraoral + transbuccal 4-hole miniplate at the external oblique line (n = 10) (G2) Single rectangular 2.0-mm 6- or 8-hole 3D miniplate (n = 10) (G1) Single 2.0-mm Intraoral 4-hole miniplate at the external oblique line (n = 7) (G2) Single curved 2.0-mm 10-hole 3D miniplate (n = 6)
Teeth retained/ removed (in MFs) Surgical approach
Antibiotics/ Length of Postoperation, operative chlorhexidine, min, mean MMF (n) days MAF fixation methods Patient age range Study Patients (mean), years Follow-up Published design (n) Authors
712
Table 1 (Continued )
periods. The overall results indicated that the use of neither 3D nor standard miniplates had a significant effect on the outcome of postoperative malocclusion (fixed: OR 0.15, 95% CI 0.02–1.11; P = 0.06), even though there was a trend favouring the 3D miniplate. There was an absence of heterogeneity among the studies (x2 = 0.00, df = 1, P = 0.97; I2 = 0%). Wound dehiscence
The incidence of wound dehiscence was reported in five studies (289 fractures). There was no statistically significant effect on the outcome of wound dehiscence favouring the 3D miniplate group (fixed: OR 0.63, 95% CI 0.20–1.97; P = 0.43). There was an absence of heterogeneity among the studies (x2 = 2.47, df = 3, P = 0.48; I2 = 0%). Hardware failure
All included studies analysed the incidence of hardware failure (309 fractures). The cumulative analysis showed a statistically significant difference in the outcome favouring 3D miniplates (fixed: OR 0.18, 95% CI 0.05–0.60; P = 0.005). The test of heterogeneity resulted in x2 = 0.45, df = 3, P = 0.93; I2 = 0%. Non-union/malunion
All included studies evaluated the incidence of non-union/malunion (309 fractures). The analysis revealed no statistical advantage for the 3D miniplate with respect to union (fixed: OR 0.86, 95% CI 0.21–3.46; P = 0.83). There was an absence of heterogeneity among the studies (x2 = 0.28, df = 1, P = 0.59; I2 = 0%). Paresthesia
The incidence of paresthesia of the inferior alveolar nerve was reported in five studies (203 fractures). The cumulative analysis showed that there was no statistically significant difference between the 3D and standard miniplate groups (fixed: OR 0.81, 95% CI 0.23–2.86; P = 0.74) and no heterogeneity present among the studies (x2 = 1.08, df = 2, P = 0.58; I2 = 0%). Trismus
Only two studies evaluated postoperative mouth opening (110 fractures). The overall effect indicated that there was a decreased amount of trismus in the 3D miniplate group (fixed: OR 0.23, 95% CI 0.06–0.86; P = 0.03). There was an
3D vs. standard miniplate meta-analysis
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Table 2. Results of the quality assessment.
Authors
Published
Random selection in population
Ho¨fer et al.18 Singh et al.16 Guy et al.19 Moore et al.20 Vineeth et al.10 Xue et al.17
2012 2012 2013 2013 2013 2013
No Yes No No Yes Yes
Defined inclusion/ exclusion criteria
Loss of follow-up
Validated measurement
Statistical analysis
Estimated potential risk of bias
Yes Yes Yes Yes Yes Yes
Yes Yes No No Yes Yes
Yes Yes Yes No Yes Yes
Yes Yes Yes Yes Yes Yes
Moderate Low Moderate High Low Low
absence of heterogeneity among the studies (x2 = 1.04, df = 1, P = 0.31; I2 = 4%)
asymmetry, indicating the absence of publication bias (Fig. 4).
The overall intervention effect
Discussion
Pooling of all outcomes to calculate the overall intervention effect was done using the following equation15:
A variety of different treatment modalities for the treatment of MAFs have been described.6,7 The so-called Champy technique has probably been the most commonly used method of fixation to date. Champy et al.8 recommended a single non-compression miniplate, ventral to the oblique line, for MAF. Although this technique has been documented to have low complication rates in some studies, as observed in a recent review,6 the stability of single miniplate fixation for MAF has been challenged in several biomechanical studies.7 The use of one standard miniplate leads to the opening of the fracture line at the lower border, lateral displacement of the fragments at the inferior border, and posterior open bite on the fracture side,10 and this fracture movement is thought to contribute to subsequent complications. More recently, 3D titanium miniplates and screws have been developed. One of the advantages of the technique is the simultaneous stabilization of the tension and compression zones, making the 3D plates a time-saving alternative to conventional miniplates.7 Although the strut plate is relatively new in the management of MAFs, it has demonstrated good clinical results in the literature.6 The aim of this review was to verify through a meta-analysis whether there is a significant difference in the clinical outcomes between standard and 3D miniplate fixation in the management of MAFs. In general, the results of the present metaanalysis show statistically higher complication rates when standard plates are used, and this observation has important clinical implications. It was observed that MAF fixation with 3D miniplates decreases the risk of postoperative complications by 58% compared to standard miniplates (cumulative OR 0.42). Some of the trials included appeared to be underpowered to
z¼
logu ; SEflogug
where log u is the estimate of effect, SE{log u} is the standard error of the estimate, and the OR, risk ratio, and other ratio measures are considered on the log scale. The cumulative analysis revealed a statistically significant advantage for the 3D miniplate when the incidences of all postoperative complications were considered (OR 0.42, 95% CI 0.27–0.66; P = 0.0002). The test of heterogeneity among all studies showed homogeneity (x2 = 13.60, df = 22, P = 0.92; I2 = 0%), as well as the test for subgroup differences (inconsistency across the subgroups) (x2 = 6.32, df = 6, P = 0.39; I2 = 5.1%). The cumulative OR was 0.42, meaning that the use of the 3D miniplate in the fixation of MAFs decreased the risk of the event (postoperative complication) by 58%. Length of operation
Four studies (183 patients) provided information on the mean operation time. However, only one study18 reported the standard deviation, which is necessary for the calculation of comparisons in continuous outcomes. Thus, a proper comparison between these studies was not possible (Fig. 3). Sensitivity analysis and publication bias
The cumulative analysis after exclusion of those studies with a high risk of bias did not change the overall main results. The funnel plot did not show any noticeable
detect a clinically significant difference in some of the postoperative complications, even though they showed clear trends favouring the use of the 3D miniplate. However, a statistically and clinically significant difference in the incidence of complications was found after the metaanalyses, stressing the importance of meta-analyses to increase the sample size of individual trials in order to reach more precise estimates of the effects of interventions. This statistically significant difference in the incidence of complications may be related to the interfragmentary stability. Not all MAFs require operative treatment, but all successful treatment of mandible fractures depends on undisturbed healing in the correct anatomical position under stable conditions. Failure to achieve this leads to infection, malocclusion, or nonunion.10 The 3D miniplate technique facilitates the reduction and stabilization at both the superior and inferior borders.11 Vineeth et al.10 observed that the 3D titanium miniplates showed better initial interfragmentary stability over single titanium miniplates in their study. The results of an in vitro study21 suggest that the 3D miniplate technique has more favourable biomechanical behaviour than the Champy technique. The better interfragmentary stability may have had an influence on the lower rates of some postoperative complications found with the use of 3D miniplate fixation in the management of MAFs, even though a statistically significant difference between the techniques was not shown for all of them. The difference between the techniques concerning the incidence of wound dehiscence (3.2% in the 3D miniplate group, 4.9% in the standard miniplate group) may be related to the proximity of the standard miniplate to the incision, when placed on the external oblique line according to the Champy technique. This is rarely seen with the 3D miniplate as it is covered by the masseter along the buccal cortex, well away from the incision.17,20 However, the differences between groups for
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Fig. 2. Forest plots for the effect of intervention (dichotomous outcomes).
the incidence of wound dehiscence did not reach statistical significance (P = 0.43). Two studies18,19 showed the operating time using the 3D plating system to be
shorter, whereas two others16,17 showed that the standard plating system had a shorter operating time. However, an appropriate comparison of the techniques
concerning the mean operation time was not possible due to missing data necessary to compare continuous outcomes in metaanalyses (the standard deviation). One might expect the operating time to be shorter with the 3D plating system because the surgeon needs to place only one plate instead of two separate conventional miniplates. However, due to the broad size of the plate and because more screws are needed (6–10 holes), fixation of 3D plates in the angle region usually takes more time. Intraoral placement of the six- to 10-hole 3D miniplate is also more difficult.16 No statistically significant difference in the incidence of paresthesia was observed between the two techniques (P = 0.74). However, most of the studies did not verify whether the paresthesia was present before surgery, because the main cause of sensory nerve abnormalities in MAFs is the degree of displacement of the segments.22 During surgery, aggressive manipulation due to fracture replacement may cause additional nerve injury, and sometimes drill-hole preparation near the mandibular canal may also cause permanent alterations.22 Therefore, if paresthesia is not checked before surgery, it may appear that all paresthesia present after surgery resulted from the surgery. There is little information in the literature concerning the incidence and natural history of inferior alveolar sensory deficits as a consequence of the fracture or as a complication of fracture fixation, as the postinjury/pretreatment sensory status is often not recorded.23 All studies reported patients with additional MFs, which may act as a confounding variable and thus affect the treatment outcome. An additional fracture may contribute to instability at the fracture site, leading to impaired bone healing, predisposing to infection, or malocclusion. Only a study of isolated MAF would allow us to establish the true complication rate for these fractures.23 The period of follow-up is also an important factor to be considered, because many studies report only short mean periods of follow-up, although it is difficult to judge what would be considered a short or a long period of follow-up.6 The maximum follow-up period in the studies reviewed here varied between 3 and 12 months. Many minor complications such as fracture or exposure of the bone plate may occur months or even years after successful healing but must still be considered a complication, as they result in a surgical intervention that would not otherwise have been necessary. The
3D vs. standard miniplate meta-analysis
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Fig. 3. Forest plot for the effect of intervention (continuous outcomes).
4.
5.
6.
7.
8.
Fig. 4. Funnel plot – publication bias according to the reported incidence of postoperative complications.
complication rate therefore may increase with the length of follow-up.23 The authors believe that new research efforts should be concentrated on a comparison between these two techniques of fixation in a larger sample size of patients with isolated MAFs, through a longer follow-up period. Such a study is necessary in order to reliably evaluate whether one technique of fixation will result in lower postoperative complication rates than the other. In conclusion, the results of this metaanalysis identified lower complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs. It is suggested that the advantages of this technique are not limited to technical ease (as presented in the literature), but also include lower patient morbidity. Funding
None.
9.
Competing interests
None declared. 10.
Ethical approval
Not required. Patient consent
Not required.
11.
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Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Lancet 2007;370:1453–7. Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009;6: e1000097. Higgins JP, Green S. Cochrane handbook for systematic reviews of interventions, Version 5. 1. 0 (updated March 2011). The Cochrane Collaboration; 2011. Singh V, Puri P, Arya S, Malik S, Bhagol A. Conventional versus 3-dimensional miniplate in management of mandibular fracture: a prospective randomized study. Otolaryngol Head Neck Surg 2012;147:450–5. Xue AS, Koshy JC, Wolfswinkel EM, Weathers WM, Marsack KP, Hollier Jr LH. A prospective study of strut versus miniplate for fractures of mandibular angle.
18.
19.
20.
21.
Craniomaxillofac Trauma Reconstr 2013;6: 191–6. Ho¨fer SH, Ha L, Ballon A, Sader R, Landes C. Treatment of mandibular angle fractures—linea obliqua plate versus grid plate. J Craniomaxillofac Surg 2012;40:807–11. Guy WM, Mohyuddin N, Burchhardt D, Olson KL, Eicher SA, Brissett AE. Repairing angle of the mandible fractures with a strut plate. JAMA Otolaryngol Head Neck Surg 2013;139:592–7. Moore E, Bayrak S, Moody M, Key JM, Vural E. Hardware removal rates for mandibular angle fractures: comparing the 8-hole strut and Champy plates. J Craniofac Surg 2013;24:163–5. Alkan A, Celebi N, Ozden B, Bas¸ B, Inal S. Biomechanical comparison of different plating techniques in repair of mandibular angle fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:752–6.
22. Farmand M. Erfahrungen bei der 3-D-Miniplattenosteosynthese bei Unterkieferfrakturen. Fortschr Kiefer Gesichtschir 1996;41: 85–7. 23. Barry CP, Kearns GJ. Superior border plating technique in the management of isolated mandibular angle fractures: a retrospective study of 50 consecutive patients. J Oral Maxillofac Surg 2007;65:1544–9.
Address: Essam Ahmed Almoraissi Department of Oral and Maxillofacial Surgery Faculty of Oral and Dental Medicine Cairo University Cairo Egypt Tel: +20 1141477753,+967 777788939 E-mails: [email protected], [email protected]
Systematic Review Trauma
Three-dimensional versus standard miniplate fixation in the management of mandibular angle fractures: a systematic review and meta-analysis
` . Al-Moraissi1,2, E. A T. M. El-Sharkawy1, T. I. El-Ghareeb1, B. R. Chrcanovic3 1 Department of Oral and Maxillofacial Surgery, Faculty of Oral and Dental Medicine, Cairo University, Egypt; 2Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Thamar University, Yemen; 3Department of Prosthodontics, Faculty of Odontology, Malmo¨ University, Sweden
E. A`. Al-Moraissi, T. M. El-Sharkawy, T. I. El-Ghareeb, B. R. Chrcanovic: Threedimensional versus standard miniplate fixation in the management of mandibular angle fractures: a systematic review and meta-analysis. Int. J. Oral Maxillofac. Surg. 2014; 43: 708–716. # 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. The aim of the present study was to test whether there is a significant difference in the clinical outcomes between standard and three-dimensional (3D) miniplate fixation in the management of mandibular angle fractures (MAFs). An electronic search without date and language restrictions was performed in October 2013. Inclusion criteria were studies in humans including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. Six studies were included. The meta-analyses revealed statistically significant differences for the incidence of hardware failure and postoperative trismus. There were no significant differences in the incidence of postoperative infection, malocclusion, wound dehiscence, non-union/malunion, or paresthesia. The cumulative odds ratio was 0.42, meaning that the use of 3D miniplates in the fixation of MAFs decreases the risk of the event (postoperative complication) by 58%. The results of this meta-analysis showed lower postoperative complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs.
Approximately 19–40% of all facial fractures are fractures of the mandible, and 12–30% of all mandibular fractures (MFs) are fractures of the mandibular angle.1–5 Among MFs, the angle is the first most frequent region for fractures caused by sports activities, the second most frequent 0901-5027/060708 + 09 $36.00/0
region for fractures caused by violence, and the third most fractured region in cases of traffic accidents involving automobiles.5 Although there is widespread agreement regarding the need for surgical reduction and fixation of a mandibular angle fracture (MAF), a variety of differ-
Key words: mandibular angle fracture; surgical treatment; rigid fixation; conventional miniplate; 3D miniplate; complications. Accepted for publication 10 February 2014 Available online 15 March 2014
ent treatment modalities have been described.6,7 The so-called ‘Champy technique’ has probably been the most commonly used method of fixation to date. The biomechanical studies of Champy et al.8 resulted in the concept of an ideal line of osteosynthesis.
# 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
3D vs. standard miniplate meta-analysis They used blocks made of a photoelastic resin to represent the mandible. A plate was then secured to the lateral surface of the blocks along the superior border, and the complex was subjected to simple cantilever loading. The test showed that the pattern of stress distribution created in the plated blocks was similar to the uncut blocks. This study was instrumental in establishing the concept of tension band plating for the treatment of MFs. Taking into account torsional tensile and compressive forces at all points of the mandible, the ideal lines of osteosynthesis were described, and this formed the basis of the internal fixation of MFs with miniplates. In the case of MAFs, results have demonstrated that the best site for plating is the vestibular osseous flat part located in the third molar region, which will counteract the muscular forces that act naturally to distract the fragments. It has also been suggested that an osteosynthesis located lower down, on the outer surface of the mandible, is solid enough to support the strain resulting from the masticatory forces in this region. However, the stability of the single miniplate fixation of MAFs has been challenged in several biomechanical studies.7 The use of three-dimensional (3D) strut plates has been one of the methods of fixation to challenge the Champy technique for the fixation of MAFs, with a growing number of clinical studies.6 The 3D plates can be considered a two-plate system, with two miniplates joined by interconnecting crossbars.9 Their shape is based on the principle of the quadrilateral as a geometrically stable configuration for support.10 Because the screws are arranged in the configuration of a box on both sides of the fracture, a broad-band platform is created, increasing the resistance to twisting and bending of the long axis of the Plate.11 There is a simultaneous stabilization of the tension and compression zones, making 3D plates a time-saving alternative to conventional miniplates. Moreover, this system is simple to apply because of its malleability, low profile (reduced palpability), and ease of application (requires little or no additional contouring).11 As philosophies on the treatment of maxillofacial trauma alter over time, a periodic review of the different concepts is necessary to refine techniques and eliminate unnecessary procedures. This would form the basis for optimum treatment. Thus, the objective of this study was to address the focused question ‘Is there a significant difference in the clinical outcomes between standard and 3D miniplate
fixation in the management of MAFs?’ by conducting a systematic review and metaanalysis of prospective studies published in the dental literature up to and including October 2013. Materials and methods Data sources and key words
An electronic search without date or language restrictions was performed in the following databases: PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, Medline, Alt HealthWatch, Health Source: Consumer Edition, Health Source: Nursing/Academic Edition, CINAH, SPORTDiscus, and Electronic Journal Centre. The key words and combinations of these used in the search included: ‘conventional AND versus AND 3-dimensional AND miniplate AND management AND mandibular angle AND fracture,’ ‘standard miniplate versus AND 3-dimensional AND fixation AND mandibular angle AND fracture,’ ‘Champy technique versus 3-dimensional miniplate AND fixation AND mandibular angle AND fracture,’ ‘mandibular angle,’ ‘miniplate,’ ‘threedimensional,’ ‘standard or conventional,’ ‘rigid fixation,’ ‘osteosynthesis,’ ‘grid miniplate,’ ‘matrix miniplate,’ ‘3D strut miniplate,’ and ‘Champy.’ A manual search of oral and maxillofacial surgery-related journals, including the International Journal of Oral and Maxillofacial Surgery, British Journal of Oral and Maxillofacial Surgery, Journal of Oral and Maxillofacial Surgery, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, Journal of CranioMaxillofacial Surgery, Journal of Craniofacial Surgery, and Journal of Maxillofacial and Oral Surgery, was also performed. Relevant reviews on the subject and the reference lists of the studies identified were also scanned for possible additional studies. Moreover, online databases providing information on clinical trials in progress were checked (http://clinicaltrials.gov; http://www.centerwatch.com/ clinical-trials; http://www.clinicalconnection.com).
Inclusion and exclusion criteria
Inclusion criteria were studies in humans including randomized or quasi randomized controlled trials (RCTs), controlled clinical trials (CCTs), and retrospective studies with the aim of comparing 3D and standard miniplate fixation techniques
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in the management of MAFs, and reporting the incidence of postoperative complications. Exclusion criteria were: (1) case reports, technical reports, animal studies, in vitro studies, and review papers, (2) studies including infected comminuted MAFs, and (3) studies including angle fractures in atrophic edentulous mandibles. Selection of relevant studies
The four authors independently assessed the eligibility of all studies retrieved from the databases. Disagreements concerning the selected studies were resolved by discussion. The following data were extracted (when available) from the studies included in the final analysis: year of publication, study design, number of patients, patient age range and/or mean age, follow-up period, number of MFs, region of MFs, fixation methods, surgical approach, length of operation, postoperative maxillomandibular fixation (MMF), use of antibiotics and/or chlorhexidine, number of teeth retained and removed, mouth opening, postoperative radiological assessment, and postoperative complications (infection, postoperative occlusion, hardware failure, segmental mobility, malunion, non-union, wound dehiscence, inferior alveolar nerve paresthesia, unstable fracture fragments). Authors were contacted for possible missing data. Quality assessment
A methodological quality rating was performed by combining the proposed criteria of the MOOSE statement,12 STROBE statement,13 and PRISMA,14 in order to verify the strength of scientific evidence in clinical decision-making. The classification of the risk of potential bias for each study was based on the following five criteria: random selection in the population, definition of inclusion/ exclusion criteria, report of losses to follow-up, validated measurements, and statistical analysis. A study that included all the criteria mentioned above was classified as having a low risk of bias, a study that did not include one of these criteria was classified as having a moderate risk of bias. When two or more criteria were missing, the study was considered to have a high risk of bias. Meta-analysis
Meta-analyses were conducted only if there were studies of similar comparisons
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reporting the same outcome measures. For binary outcomes, we planned to calculate a standard estimation of the odds ratio (OR) by random-effects model if heterogeneity was detected, otherwise a fixedeffect models with a 95% confidence interval (CI) was performed. Weighted mean differences were used to construct forest plots of continuous data. The data were analysed using the statistical software Review Manager (version 5.2.6; The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark, 2012). Assessment of heterogeneity
The significance of any discrepancies in the estimates of the treatment effects of the different trials was assessed by means of Cochran’s test for heterogeneity and the I2 statistic, which describes the percentage total variation across studies that is due to heterogeneity rather than chance. Heterogeneity was considered statistically significant if P < 0.1. A rough guide to the interpretation of I2 given in the Cochrane Handbook15 is as follows: (1) from 0% to 40% the heterogeneity might not be important, (2) from 30% to 60% may represent moderate heterogeneity, (3) from 50% to 90% may represent substantial heterogeneity, and (4) from 75% to 100% there is considerable heterogeneity. Investigation of publication bias
A funnel plot (plot of effect size versus standard error) was drawn. Asymmetry of a funnel plot may indicate publication bias and other biases related to sample size, although the asymmetry may also represent a true relationship between trial size and effect size. Sensitivity analysis
If there were sufficient studies included, we planned to conduct a sensitivity analysis to assess the robustness of the review results by repeating the analysis with the following adjustment: exclusion of studies with a high risk of bias. Results Literature search
The study selection process is summarized in Fig. 1. The electronic search resulted in 702 entries. Six additional articles were identified by hand-searching. After the initial screening of titles and abstracts, 382 articles were excluded due
Fig. 1. Study screening process.
to duplication. Of the remaining 326 studies, 292 were excluded for not being related to the topic. The full-text reports of the remaining 34 articles were assessed, leading to the exclusion of 28 because they did not meet the inclusion criteria. Thus, a total of six publications were included in the review. Description of studies included
Detailed data of the six studies included are listed in Table 1. Three RCTs10,16,17 and three retrospective studies18–20 were included in the meta-analysis. In total, 307 patients were enrolled in the six studies, with 196 patients (197 MAFs) in the 3D miniplates group and 111 patients (112 MAFs) in the standard miniplate group. The maximum follow-up period varied between 3 and 12 months. The length of the follow-up period was not reported in one study,20 probably because it was a retrospective review of patient charts. All studies reported patients with additional MFs. Concerning the standard miniplate group, five of the six studies performed the fixation using only a single miniplate. In four studies10,17,18,20 the MAFs were fixed at the external oblique line and in one study16 at the external oblique line or on the lateral cortex, and one study19 used one or two miniplates, but two miniplates (superior tension band miniplate and inferior border miniplate) were used in most of the patients. Four studies10,16,17,19 used four-hole standard miniplates, whereas one study18 used six-hole miniplates and one study20 used four- or six-hole miniplates. Concerning the 3D miniplate group, a rectangular 3D miniplate was used in three
studies,10,16,18 whereas a curved 3D miniplate was used in the other three.17,19,20 The number of holes in the 3D miniplates used varied widely between the studies. Four studies used a combination of intraoral approach with the use of a transbuccal trocar.10,16,19,20 Two studies exclusively used the intraoral approach without a transbuccal trocar.17,18 Four studies16–19 provided information on the mean operation time. Quality assessment
Each trial was assessed for risk of bias; the scores are summarized in Table 2. One study was judged to be at high risk of bias,20 two were considered at moderate risk,18,19 and three were considered at low risk of bias.10,16,17 Effect of intervention
The forest plots for the effect of intervention are shown in Fig. 2. Infection
Data on postoperative infection were given in all studies (309 fractures). The cumulative analysis revealed an advantage for the 3D miniplate group regarding infection (fixed: OR 0.48, 95% CI 0.19– 1.22), but this advantage did not reach statistical significance (P = 0.12). The test of heterogeneity resulted in x2 = 2.61, df = 5, with P = 0.76, indicating homogeneity of studies. Malocclusion
Five studies (203 fractures) evaluated malocclusion, but with inconsistent follow-up
Table 1. Studies comparing three-dimensional and standard miniplate fixation techniques in the management of mandibular angle fractures.
Authors
Patient age range Study Patients (mean), years Follow-up Published design (n)
Region MFs of MFs
MAF fixation methods
Surgical approach
RA
60
15–73 (31.1)
7 days 14 days 28 days 3 months 6 months 12 months
90
Angle (n = 60), bodyb (n = 25), ascending ramusb (n = 5)
(G1) Single 2.0-mm Intraoral 6-hole miniplate at the external oblique line (n = 30) (G2) Single rectangular 2.0-mm 4-hole 3D miniplate (n = 30)
Singh et al.16,a
2012
RCT
50
17–46 (30.4)
1 week 4 weeks 8 weeks 12 weeks
56
Angle (n = 20), parasymphysis (n = 35), symphysis (n = 1)
Guy et al.19
2013
RA
90
14–58 (28)
8–308 days 161 (mean 47; G1) 2–355 days (mean 55; G2)
(G1) Single 2.0-mm 4-hole miniplate at the external oblique line or on the lateral cortex (n = 10) (G2) Single rectangular 2.0-mm 6-hole 3D miniplate (n = 10) (G1) One or two 2.0-mm 4-hole miniplate (n = 22)c (G2) Single curved 2.0-mm 8-hole 3D miniplate (n = 68)
Moore et al.20
2013
RA
104
NM (31)
NM
168
Angle (n = 96), parasymphysis (n = 41), body (n = 11), condyle (n = 5), coronoid (n = 2), ramus (n = 6) Angle (n = 106), parasymphysis (n = 11), body (n = 51)
Teeth retained/ removed (in MFs)
89 (G1) 81 (G2)
NP
4/NM
Intraoral or intraoral + transbuccal
44 (G1) 57 (G2)
17 (G1) 8 (G2)
5/NM
Intraoral + transbuccal (G1, G2), extraoral (9% in G1)
232 (G1) 219 (G2)
14; 64% (G1) 35; 51% (G2)
7/preoperative and operative
NM
NM
NP
‘Post-operative’/ NM
NM
(G1) Single 2.0-mm Intraoral + transbuccal 4- or 6-hole miniplate at the external oblique line (n = 33) (G2) Single curved 2.0-mm 8-hole 3D miniplate (n = 73)
‘Third molars were not removed during surgical intervention unless they were also fractured, luxated or they prevented an appropriate reduction.’ ‘Extraction of teeth in the line of fracture was performed if indicated’
3D vs. standard miniplate meta-analysis
Ho¨fer 2012 et al.18,a
Antibiotics/ Length of Postoperation, operative chlorhexidine, min, mean MMF (n) days
711
3 (G1) 1 (G2)
5–7/‘0.1%, from the time of presentation’
19/1
42 (G1) 102 (G2)
NP
5–7 days/‘ provided to all patients’
0/7
NM, not mentioned; NP, not performed; RCT, controlled clinical trial; RA, retrospective analysis; MF, mandibular fracture; MAF, mandibular angle fracture; G1, group 1 (standard miniplates); G2, group 2 (3D miniplates); MMF, maxillomandibular fixation. a Personal communication was performed with one of the authors in order to obtain some missing data. b Mandibular fracture regions not being compared with the two different fixation types (conventional miniplates versus 3D miniplates). c Guy et al.19 divided their patients into strut plate and non-strut plate groups, with 68 and 22 patients, respectively. For the 22 patients in the non-strut group, the mandibular fractures of one patient were fixed with one miniplate at the external oblique line, and the mandibular fractures of 16 patients were fixed with two miniplates (superior tension band miniplate and inferior border miniplate), giving a total of 17 patients in whom miniplates were used. d A total of 18 patients were included in this study, however five were excluded postoperatively due to complex fractures resulting in postoperative MMF.
Al-Moraissi et al.
NM
Region MFs of MFs Vineeth et al.10
2013
RCT
20
19–51 (NM)
1 1 1 3
day week month months
29
Angle (n = 20), additional fracturesb (n = 9; G1, n = 5; G2, n = 4) Xue et al.17
2013
RCT
13 (18)d
NM (NM)
1–2 weeks 4–6 weeks 6 months
22
Angle (n = 13), parasymphysis (n = 8), subcondylar (n = 1)
(G1) Single 2.0-mm Intraoral + transbuccal 4-hole miniplate at the external oblique line (n = 10) (G2) Single rectangular 2.0-mm 6- or 8-hole 3D miniplate (n = 10) (G1) Single 2.0-mm Intraoral 4-hole miniplate at the external oblique line (n = 7) (G2) Single curved 2.0-mm 10-hole 3D miniplate (n = 6)
Teeth retained/ removed (in MFs) Surgical approach
Antibiotics/ Length of Postoperation, operative chlorhexidine, min, mean MMF (n) days MAF fixation methods Patient age range Study Patients (mean), years Follow-up Published design (n) Authors
712
Table 1 (Continued )
periods. The overall results indicated that the use of neither 3D nor standard miniplates had a significant effect on the outcome of postoperative malocclusion (fixed: OR 0.15, 95% CI 0.02–1.11; P = 0.06), even though there was a trend favouring the 3D miniplate. There was an absence of heterogeneity among the studies (x2 = 0.00, df = 1, P = 0.97; I2 = 0%). Wound dehiscence
The incidence of wound dehiscence was reported in five studies (289 fractures). There was no statistically significant effect on the outcome of wound dehiscence favouring the 3D miniplate group (fixed: OR 0.63, 95% CI 0.20–1.97; P = 0.43). There was an absence of heterogeneity among the studies (x2 = 2.47, df = 3, P = 0.48; I2 = 0%). Hardware failure
All included studies analysed the incidence of hardware failure (309 fractures). The cumulative analysis showed a statistically significant difference in the outcome favouring 3D miniplates (fixed: OR 0.18, 95% CI 0.05–0.60; P = 0.005). The test of heterogeneity resulted in x2 = 0.45, df = 3, P = 0.93; I2 = 0%. Non-union/malunion
All included studies evaluated the incidence of non-union/malunion (309 fractures). The analysis revealed no statistical advantage for the 3D miniplate with respect to union (fixed: OR 0.86, 95% CI 0.21–3.46; P = 0.83). There was an absence of heterogeneity among the studies (x2 = 0.28, df = 1, P = 0.59; I2 = 0%). Paresthesia
The incidence of paresthesia of the inferior alveolar nerve was reported in five studies (203 fractures). The cumulative analysis showed that there was no statistically significant difference between the 3D and standard miniplate groups (fixed: OR 0.81, 95% CI 0.23–2.86; P = 0.74) and no heterogeneity present among the studies (x2 = 1.08, df = 2, P = 0.58; I2 = 0%). Trismus
Only two studies evaluated postoperative mouth opening (110 fractures). The overall effect indicated that there was a decreased amount of trismus in the 3D miniplate group (fixed: OR 0.23, 95% CI 0.06–0.86; P = 0.03). There was an
3D vs. standard miniplate meta-analysis
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Table 2. Results of the quality assessment.
Authors
Published
Random selection in population
Ho¨fer et al.18 Singh et al.16 Guy et al.19 Moore et al.20 Vineeth et al.10 Xue et al.17
2012 2012 2013 2013 2013 2013
No Yes No No Yes Yes
Defined inclusion/ exclusion criteria
Loss of follow-up
Validated measurement
Statistical analysis
Estimated potential risk of bias
Yes Yes Yes Yes Yes Yes
Yes Yes No No Yes Yes
Yes Yes Yes No Yes Yes
Yes Yes Yes Yes Yes Yes
Moderate Low Moderate High Low Low
absence of heterogeneity among the studies (x2 = 1.04, df = 1, P = 0.31; I2 = 4%)
asymmetry, indicating the absence of publication bias (Fig. 4).
The overall intervention effect
Discussion
Pooling of all outcomes to calculate the overall intervention effect was done using the following equation15:
A variety of different treatment modalities for the treatment of MAFs have been described.6,7 The so-called Champy technique has probably been the most commonly used method of fixation to date. Champy et al.8 recommended a single non-compression miniplate, ventral to the oblique line, for MAF. Although this technique has been documented to have low complication rates in some studies, as observed in a recent review,6 the stability of single miniplate fixation for MAF has been challenged in several biomechanical studies.7 The use of one standard miniplate leads to the opening of the fracture line at the lower border, lateral displacement of the fragments at the inferior border, and posterior open bite on the fracture side,10 and this fracture movement is thought to contribute to subsequent complications. More recently, 3D titanium miniplates and screws have been developed. One of the advantages of the technique is the simultaneous stabilization of the tension and compression zones, making the 3D plates a time-saving alternative to conventional miniplates.7 Although the strut plate is relatively new in the management of MAFs, it has demonstrated good clinical results in the literature.6 The aim of this review was to verify through a meta-analysis whether there is a significant difference in the clinical outcomes between standard and 3D miniplate fixation in the management of MAFs. In general, the results of the present metaanalysis show statistically higher complication rates when standard plates are used, and this observation has important clinical implications. It was observed that MAF fixation with 3D miniplates decreases the risk of postoperative complications by 58% compared to standard miniplates (cumulative OR 0.42). Some of the trials included appeared to be underpowered to
z¼
logu ; SEflogug
where log u is the estimate of effect, SE{log u} is the standard error of the estimate, and the OR, risk ratio, and other ratio measures are considered on the log scale. The cumulative analysis revealed a statistically significant advantage for the 3D miniplate when the incidences of all postoperative complications were considered (OR 0.42, 95% CI 0.27–0.66; P = 0.0002). The test of heterogeneity among all studies showed homogeneity (x2 = 13.60, df = 22, P = 0.92; I2 = 0%), as well as the test for subgroup differences (inconsistency across the subgroups) (x2 = 6.32, df = 6, P = 0.39; I2 = 5.1%). The cumulative OR was 0.42, meaning that the use of the 3D miniplate in the fixation of MAFs decreased the risk of the event (postoperative complication) by 58%. Length of operation
Four studies (183 patients) provided information on the mean operation time. However, only one study18 reported the standard deviation, which is necessary for the calculation of comparisons in continuous outcomes. Thus, a proper comparison between these studies was not possible (Fig. 3). Sensitivity analysis and publication bias
The cumulative analysis after exclusion of those studies with a high risk of bias did not change the overall main results. The funnel plot did not show any noticeable
detect a clinically significant difference in some of the postoperative complications, even though they showed clear trends favouring the use of the 3D miniplate. However, a statistically and clinically significant difference in the incidence of complications was found after the metaanalyses, stressing the importance of meta-analyses to increase the sample size of individual trials in order to reach more precise estimates of the effects of interventions. This statistically significant difference in the incidence of complications may be related to the interfragmentary stability. Not all MAFs require operative treatment, but all successful treatment of mandible fractures depends on undisturbed healing in the correct anatomical position under stable conditions. Failure to achieve this leads to infection, malocclusion, or nonunion.10 The 3D miniplate technique facilitates the reduction and stabilization at both the superior and inferior borders.11 Vineeth et al.10 observed that the 3D titanium miniplates showed better initial interfragmentary stability over single titanium miniplates in their study. The results of an in vitro study21 suggest that the 3D miniplate technique has more favourable biomechanical behaviour than the Champy technique. The better interfragmentary stability may have had an influence on the lower rates of some postoperative complications found with the use of 3D miniplate fixation in the management of MAFs, even though a statistically significant difference between the techniques was not shown for all of them. The difference between the techniques concerning the incidence of wound dehiscence (3.2% in the 3D miniplate group, 4.9% in the standard miniplate group) may be related to the proximity of the standard miniplate to the incision, when placed on the external oblique line according to the Champy technique. This is rarely seen with the 3D miniplate as it is covered by the masseter along the buccal cortex, well away from the incision.17,20 However, the differences between groups for
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Fig. 2. Forest plots for the effect of intervention (dichotomous outcomes).
the incidence of wound dehiscence did not reach statistical significance (P = 0.43). Two studies18,19 showed the operating time using the 3D plating system to be
shorter, whereas two others16,17 showed that the standard plating system had a shorter operating time. However, an appropriate comparison of the techniques
concerning the mean operation time was not possible due to missing data necessary to compare continuous outcomes in metaanalyses (the standard deviation). One might expect the operating time to be shorter with the 3D plating system because the surgeon needs to place only one plate instead of two separate conventional miniplates. However, due to the broad size of the plate and because more screws are needed (6–10 holes), fixation of 3D plates in the angle region usually takes more time. Intraoral placement of the six- to 10-hole 3D miniplate is also more difficult.16 No statistically significant difference in the incidence of paresthesia was observed between the two techniques (P = 0.74). However, most of the studies did not verify whether the paresthesia was present before surgery, because the main cause of sensory nerve abnormalities in MAFs is the degree of displacement of the segments.22 During surgery, aggressive manipulation due to fracture replacement may cause additional nerve injury, and sometimes drill-hole preparation near the mandibular canal may also cause permanent alterations.22 Therefore, if paresthesia is not checked before surgery, it may appear that all paresthesia present after surgery resulted from the surgery. There is little information in the literature concerning the incidence and natural history of inferior alveolar sensory deficits as a consequence of the fracture or as a complication of fracture fixation, as the postinjury/pretreatment sensory status is often not recorded.23 All studies reported patients with additional MFs, which may act as a confounding variable and thus affect the treatment outcome. An additional fracture may contribute to instability at the fracture site, leading to impaired bone healing, predisposing to infection, or malocclusion. Only a study of isolated MAF would allow us to establish the true complication rate for these fractures.23 The period of follow-up is also an important factor to be considered, because many studies report only short mean periods of follow-up, although it is difficult to judge what would be considered a short or a long period of follow-up.6 The maximum follow-up period in the studies reviewed here varied between 3 and 12 months. Many minor complications such as fracture or exposure of the bone plate may occur months or even years after successful healing but must still be considered a complication, as they result in a surgical intervention that would not otherwise have been necessary. The
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715
Fig. 3. Forest plot for the effect of intervention (continuous outcomes).
4.
5.
6.
7.
8.
Fig. 4. Funnel plot – publication bias according to the reported incidence of postoperative complications.
complication rate therefore may increase with the length of follow-up.23 The authors believe that new research efforts should be concentrated on a comparison between these two techniques of fixation in a larger sample size of patients with isolated MAFs, through a longer follow-up period. Such a study is necessary in order to reliably evaluate whether one technique of fixation will result in lower postoperative complication rates than the other. In conclusion, the results of this metaanalysis identified lower complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs. It is suggested that the advantages of this technique are not limited to technical ease (as presented in the literature), but also include lower patient morbidity. Funding
None.
9.
Competing interests
None declared. 10.
Ethical approval
Not required. Patient consent
Not required.
11.
References 1. Chrcanovic BR, Freire-Maia B, Souza LN, Arau´jo VO, Abreu MH. Facial fractures: a 1year retrospective study in a hospital in Belo Horizonte. Braz Oral Res 2004;18:322–8. 2. Chrcanovic BR, Abreu MH, Freire-Maia B, Souza LN. Facial fractures in children and adolescents: a retrospective study of 3 years in a hospital in Belo Horizonte, Brazil. Dent Traumatol 2010;26:262–70. 3. Chrcanovic BR, Souza LN, Freire-Maia B, Abreu MH. Facial fractures in the elderly: a
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Address: Essam Ahmed Almoraissi Department of Oral and Maxillofacial Surgery Faculty of Oral and Dental Medicine Cairo University Cairo Egypt Tel: +20 1141477753,+967 777788939 E-mails: [email protected], [email protected]
