Which fixation methods are better between three-dimensional anatomical plate and two miniplates for the mandibular subcondylar fracture open treatment?

Biomechanical evaluation of various rigid internal fixation modalities for condylar-base-associated multiple mandibular fractures: A finite element analysis

Condylar-base-associated multiple mandibular fractures are more prevalent than single ones. Direct trauma to mandibular symphysis, body or angle are prone to induce indirect condylar fracture. However, little is known about the effects of various rigid internal fixation modalities in condylar base for relevant multiple mandibular fractures, especially when we are confused in the selection of operative approach. Within the finite element analysis, straight-titanium-plate implanting positions in condylar base contained posterolateral zone (I), anterolateral zone (II), and intermediate zone (III). Von Mises stress (SS) in devices and bone and mandibular displacement (DT) were solved, while maximum values (SSmax and DTmax) were documented. For rigid internal fixation in condylar-base-and-symphysis fractures, I + II modality exhibited least SSmax in screws and cortical bone and least DTmax, I + III modality exhibited least SSmax in plates. For rigid internal fixation in condylar-base-and-contralateral-body fractures, I + III modality exhibited least SSmax in screws and cortical bone, I + II modality exhibited least SSmax in plates and least DTmax. For rigid internal fixation in condylar-base-and-contralateral-angle fractures, I + III modality exhibited least DTmax. The findings suggest that either I + II or I + III modality is a valid guaranty for rigid internal fixation of condylar base fractures concomitant with symphysis, contralateral body or angle fractures.

Use of a novel three-dimensional anatomical plating system for treatment of caudal mandibular fractures in cats: 13 cases (2019-2023)

CASE SERIES SUMMARY

A total of 13 cases of cats with a caudal mandibular fracture treated with a novel surgical technique using the Ramus Anatomical Plate system were reviewed. Preoperative, immediate postoperative and a minimum of 8 weeks postoperative CT images were required as inclusion criteria. The outcome and complications were determined from clinical data and radiographic follow-up examinations. All cases achieved adequate anatomical reduction, resulting in a functional and atraumatic occlusion postoperatively. No intraoperative complications were reported. Time to voluntary food intake was in the range of 1-25 days. No evidence of disruptions to the implants or screw loosening was observed in the 8-week postoperative CT imaging, with radiographic evidence of complete osseous union in all fractures. The most common postoperative complication was swelling at the surgical site. Two cats had postoperative exophthalmos due to retrobulbar haemorrhage, and one cat exhibited partial wound dehiscence 5 days postoperatively, which resolved with medical management. Longer-term complications included intraoral plate exposure in one cat, which required plate removal 10 months postoperatively.

RELEVANCE AND NOVEL INFORMATION

In this case series, rigid internal fixation of caudal mandibular fractures using the Ramus Anatomical Plate osteosynthesis system was associated with a minimal complication rate, and satisfactory radiographic and clinical outcomes. The reported outcomes of this novel technique are favourable when compared with previous techniques described for the management of these fracture types.

Which Factors Affect the Reduction Quality of Open Reduction Internal Fixation of Mandibular Subcondylar Fractures?

BACKGROUND

Open reduction internal fixation (ORIF) of mandibular subcondylar fractures (MSF) involves several variables that could affect decision making. There is insufficient data regarding factors influencing the outcomes of MSF ORIF.

PURPOSE

The purpose of this study was to investigate factors associated with quality of bony reduction of MSF and occlusion, after ORIF.

STUDY DESIGN, SETTING, AND SAMPLE

We designed a retrospective cohort study of consecutively treated subjects for MSF ORIF, ages 18 to 64 years, by University of Illinois' Department of Oral and Maxillofacial Surgery, between January 1, 2013, and January 26, 2021.

PREDICTOR VARIABLE

The primary predictor variable was the vertical level of MSF from the gonial angle. Secondary predictor variables included surgeon, fixation scheme (number and configuration of miniplate), surgical approach, time to surgery, mechanism of injury, vertical fragment overlap, overlying soft tissue thickness, presence of other mandibular fractures, and severity and direction of displacement.

MAIN OUTCOME VARIABLES

The primary outcome variable was the mean radiographic reduction score (RRS), rated by 2 blinded observers on a 1 to 5 scale. The secondary outcome variable was presence of postoperative malocclusion as documented in the medical records.

COVARIATES

Covariates were age and sex.

ANALYSES

Descriptive statistics were computed. To investigate the influence of the predictor variables on reduction quality, multifactorial analysis of variance with post hoc Tukey test was performed. For malocclusion, χ2 test was performed. The level of significance was set at P < .05.

RESULTS

Thirty-eight MSF in 37 subjects were included. Mean age was 32.7 years (range 18 to 64), and 83.8% were male. Mean RRS was 4.38 (standard deviation 0.77). Fixation scheme was the only variable that showed significant impact on RRS: single-straight miniplate had lower scores than double-straight (-1.50, P = .011), rhomboid (-1.29, P = .036), and ladder miniplates (-1.38, P = .048). There was 1 incidence of malocclusion (2.7%) which resolved without intervention.

CONCLUSIONS AND RELEVANCE

Favorable reduction (anatomic reduction to mild discrepancies) can be achieved without malocclusion using double-straight, or rhomboid-shaped or ladder-shaped miniplates, without influences from patient or injury-related factors. In contrast, single-straight miniplate fixation resulted in moderate discrepancies in reduction, although it did not lead to malocclusion.

Treatment for Adult Mandibular Condylar Process Fractures: A Network Meta-Analysis of Randomized Clinical Trials

PURPOSE

Using network meta-analyses (NMA) has become increasingly valuable as it enables the comparison of interventions that have not been directly compared in a clinical trial. To date, there has not been a NMA of randomized clinical trials (RCT) that compares all types of treatments for mandibular condylar process fractures (MCPFs). The aim of this NMA was to compare and rank all the available methods used in the treatment of MCPFs.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search was conducted in 3 major databases up to January 2023 to retrieve RCTs that compared various closed and open treatment methods for MCPFs. The predictor variable is treatment techniques: arch bars (ABs) + wire maxillomandibular fixation (MMF), rigid MMF with intermaxillary fixation screws, AB + functional therapy with elastic guidance (AB functional treatment), AB rigid MMF/functional treatment, single miniplate, double miniplate, lambda miniplate, rhomboid plate, and trapezoidal miniplate. Postoperative complications were the outcome variables and included occlusion, mobility, and pain, among other things. Risk ratio (RR) and standardized mean difference were calculated. Version 2 of the Cochrane risk-of-bias tool and Grading of Recommendations, Assessment, Development, and Evaluations system were used to determine the certainty of the results.

RESULTS

The NMA included a total of 10,259 patients from 29 RCTs. At ≤6 months, the NMA revealed that the use of 2-miniplates significantly reduced malocclusion compared to rigid MMF (RR = 2.93; confidence interval [CI]: 1.79 to 4.81; very low quality) and functional treatment (RR = 2.36; CI: 1.07 to 5.23; low quality).Further, at ≥6 months, 2-miniplates resulted in significantly lower malocclusion compared to rigid MMF with functional treatment (RR = 3.67; CI: 1.93 to 6.99; very low quality).Trapezoidal plate and AB functional treatment were ranked as the best options in 3-dimensional (3D) plates and closed groups, respectively.3D-miniplates (very low-quality evidence) were ranked as the most effective treatment for reducing postoperative malocclusion and improving mandibular functions after MCPFs, followed closely by double miniplates (moderate quality evidence).

CONCLUSIONS

This NMA found no substantial difference in functional outcomes between using 2-miniplates versus 3D-miniplates to treat MCPFs (low evidence).However, 2-miniplates led to better outcomes than closed treatment (moderate evidence).Additionally, 3D-miniplates produced better outcomes for lateral excursions, protrusive movements, and occlusion than closed treatment at ≤6 months (very low evidence).

Biomechanical influence of plate configurations on mandible subcondylar fracture fixation: a finite element study

Mandible subcondylar fractures have very high complication rate, yet there is no consensus on suitable plate design for optimal patient outcomes. Our study is aimed at comparing single mini, trapezoid, lambda, strut and double mini plates. A finite-element (FE) model of intact mandible was developed based on healthy CT-scan data, which was further virtually osteotomized and fixated with plates. The cortical and cancellous bones were assigned region-specific orthotropic and heterogenous isotropic material properties respectively. The models were subjected to six load cases representing the mastication cycle. Under opposite lateralities, the tensile and compressive mandibular strain distributions were found as the opposite, with tensile strains at the posterior border under ipsilateral molar clenching (RMOL) resulting in lesser mandibular strain in reconstructed mandible with single mini plate under RMOL but highest mandibular strain under the contralateral molar clenching (LMOL). Owing to the reduced mandibular strains under LMOL than RMOL, the contralateral chewing is preferred during the immediate post-surgery period for patients. Under LMOL, the peak von Mises stresses in the plate decreased with increase in the number of screws. Furthermore, the presence of two arms in double mini and trapezoid plates seems beneficial to neutralise the tensile and compressive strains across load cases.

A comparative evaluation of retromandibular versus Modified Risdon approach in surgical treatment of condylar fracture

The purpose of this study was aimed to compare the efficiency and safety of retromandibular versus modified Risdon approach using periangular incision for open reduction and internal fixation of low subcondylar mandibular fracture. Open reduction and internal fixation with different plating systems were utilized via retromandibular approach (group I) and via modified Risdon approach with periangular incision (group II). Twenty four (n= 24) condylar fractures in 21 adult patients were divided randomly into two equal groups (12 each) according to the cutaneous incision (approach) utilized. The evaluation score for scarring in group I it was excellent in 9 patients, good in 2 patients and acceptable in only one patient (Mean 2.4 ± SD 3.38). While in group II was excellent in 10 patients and good in 2 patients (Mean 2.4 ± SD 3.87) and the p value was 0.591. Symptoms of transient facial nerve weakness were noted in only 3 patients in group I with slight to moderate dysfunction (Mean 2 ± SD 3.21), while only one patient had facial nerve weakness in group II with House - Brackman score of 2 immediate postoperatively and this got resolved in 6 weeks (Mean 2 ± SD 4.04) and the p value was 0.00022. Within the limitations of the study it seems that a modified Risdon approach using periangular incision for reduction and fixation of low subcondylar fracture should be preferred whenever possible because it yields better outcomes.

Evaluation of condylar position in anterior mandibular fractures using 3 dimensional miniplate osteosynthesis versus conventional miniplates: Randomized clinical trial

To compare clinically and radiographically between the 3-D plates and the conventional two Champy's miniplates in the treatment of anterior mandibular fractures. It is a randomized clinical and radiographic comparative study between 2 equal groups of patients with isolated anterior mandibular fractures. Open reduction and internal rigid fixation was accomplished in the study group using 3D miniplates fixation while in the control group using the two Champy's miniplates. The 3D miniplate osteosynthesis consumed less operative time than the two miniplates osteosynthesis. Independent t-test revealed that the difference between the 2 groups was 8.4 ± 3.11 min. This difference was statistically significant (p=0.012). Occlusion was slightly disturbed in two patients in the study group in comparison to three patients in the control group. The difference between the 2 groups was not statistically significant (p=0.62). None of the cases of both groups showed mobility between the reduced and fixed fractured segments, immediately post-operatively and at the end of follow-up intervals. The 3D miniplate osteosynthesis (study group) recorded less intercondylar distance than two miniplates osteosynthesis (control group) immediately post-operatively and after 3 months. Independent t-test revealed that the difference between the 2 groups was not statistically significant, immediately postoperative (p=0.322) and after 3 months (p=0.263). Pre-operatively to 3 months postoperatively, the 3D miniplate osteosynthesis (study group) recorded a lower median percent increase in the intercondylar distance than the two miniplates osteosynthesis (control group). The difference between the 2 groups was not statistically significant (p=0.917). Regarding the intercondylar angle, the3D miniplate osteosynthesis (study group) recorded higher intercondylar angle than the two miniplates osteosynthesis (control group) immediately post-operative (p=0.333) and after 3 months (p=0.255). Independent t-test revealed that the difference between the 2 groups was not statistically significant. The 3-Dimensional strut miniplates should be considered an alternative for internal rigid fixation of anterior mandibular fractures for their ease of adaptation and insertion, while providing the advantage of reduced operative time compared to the conventional two Champy's miniplates.

The Use of Titanium 3D Mini-Plates in the Surgical Treatment of Fractures of the Mandibular Condyle: A Systematic Review and Meta-Analysis of Clinical Trials

Introduction: Fixing fractures of the base and neck of mandibular condyles is demanding due to the difficulties in surgical access and the various shapes of bone fragments. Classic fixation techniques assume the use of straight mini-plates, utilized for other craniofacial bone fractures. Three dimensional mini-plates may provide a reasonable alternative due to their ease of use and steadily improved mechanical properties. The multitude of different shapes of 3D mini-plates proves the need for their evaluation. Aim: This paper aims to summarize the clinical trials regarding the use of various types of 3D condylar mini-plates in terms of need for reoperation and the incidence of loosening and damage to the osteosynthetic material. Materials and Methods: A systematic review was conducted in accordance with PICOS criteria and PRISMA protocol. The risk of bias was assessed using ROBINS-I and RoB 2 Cochrane protocols. The obtained data series was analyzed for correlations (Pearson’s r) respecting statistical significance (Student’s t-test p > 0.05) and visualized using OriginLab. Results: 13 clinical trials with low overall risk of bias regarding 6 shapes of 3D mini-plates were included in the synthesis. The number of reoperations correlates with the number of fixations (r = 0.53; p = 0.015) and the total number of screw holes in the mini-plate (r = −0.45; p = 0.006). There is a strong correlation between the number of loosened osteosynthetic screws and the total number of fractures treated with 3D mini-plates (r = 0.79; p = 0.001 for each study and r = 0.99; p = 0.015 for each mini-plate shape). A correlation between the percentage of lost screws and the number of distal screw holes is weak regarding individual studies (r = −0.27; p = 0.000) and strong regarding individual mini-plate shape (r = −0.82; p = 0.001). Three cases of 3D mini-plate fractures are noted, which account for 0.7% of all analyzed fixation cases. Discussion: The reasons for reoperations indicated by the authors of the analyzed articles were: mispositioning of the bone fragments, lack of bone fragment union, secondary dislocation, and hematoma. The known screw loosening factors were poor bone quality, bilateral condylar fractures, difficulties in the correct positioning of the osteosynthetic material due to the limitations of the surgical approach, fracture line pattern, including the presence of intermediate fragments, and mechanical overload. Fractures of the straight mini-plates fixing the mandibular condyles amounts for up to 16% of cases in the reference articles. Conclusions: There is no convincing data that the number of reoperations depends on the type of 3D mini-plate used. The frequency of osteosynthetic screw loosening does not seem to depend on the 3D mini-plate’s shape. Clinical fractures of 3D mini-plates are extremely rare.

Three-Dimensional Osteosynthesis Plates for the Surgical Treatment of Mandibular Fractures

OBJECTIVES

Mandible fractures can be treated with different plate systems, that is, miniplates or three-dimensional (3D) plates. This systematic review describes the effectiveness and clinical outcomes of 3D plates used in fractures of the mandible and aims to critically evaluate its risks and benefits.

MATERIALS AND METHODS

A comprehensive electronic search was conducted without date but with restriction to articles written in English. Studies in humans, including randomized or quasi-randomized controlled trials and retrospective studies, were included. The outcome parameters measured were number of patients, fracture classification, results, follow-up period, postoperative complications, and mean age of patients. Major complications were defined as those needing additional surgical intervention, for example, malocclusion, infection or plate fracture. Accordingly, complications not needing additional surgical intervention were defined as minor (ie, dehiscence, trismus).

RESULTS

Guided by the PRISMA statement and the Cochrane Handbook for Systematic Reviews of Interventions, the authors identified 44 publications with a total of 1790 patients. Among the articles selected for the final review, there were 32 reported prospective studies, 12 reported retrospective studies. Regarding the evaluation of quality, 8 studies showed a low value of the risk of bias, 17 a moderate risk, and 19 a high risk. There were statistically significant advantages for 3D plates in mandibular fractures in terms of postoperative complications, for example, wound dehiscences or plate fracture.

CONCLUSIONS

The 3D plate is an effective treatment modality for mandibular fractures, with low incidence of major complications, decreased length of operation time, and increased stability of osteosynthesis.

Two miniplates versus 3-dimensional plate in the management of mandibular subcondylar fractures: a retrospective analysis

PURPOSE

The aim of the present study was to evaluate the outcomes in patients with subcondylar fracture of mandible treated with 2 single miniplates compared to a 3-dimensional (3D) plate.

PATIENTS AND METHODS

This is a retrospective study which included patients diagnosed and treated for mandibular subcondylar fracture from January 2015 to December 2019. Included patients were divided into two groups, group 1: 2 miniplate group and group 2: 3D plate group. The data was obtained from the patients' records and evaluated for various outcomes including occlusal stability, postoperative complications like plate fracture, non-union, plate or screw loosening, and plate or screw infection leading to implant removal, wound dehiscence, salivary fistula, and facial nerve paralysis. The statistical analysis was performed using chi square test and Student's t test.

RESULTS

A total 58 patients (43 males and 15 females) were enrolled in the two groups ranging from 21 to 59 years. A total of 35 patients were recruited in group 1, whereas 23 patients were recruited in group 2. There was no statistically significant difference in the two groups with regard to the age range, gender, diagnosis, side of fracture, and accompanying fractures. Occlusal instability, wound dehiscence, and facial nerve paralysis was found in both the groups. Group 1 had 1 patient which required implant removal due to screw loosing, whereas group 2 had 2 patients which required plate removal due to plate fracture. One patient in group 2 required second surgery for fixation of fracture due to non-union. One patient in group 1 developed a sialocele postoperatively. However, there was no statistically significant difference in any of the variables assessed among the two groups (p > 0.05).

CONCLUSION

The results of our study indicate that the 2 miniplates and 3D plate system are effective in the management of mandibular subcondylar fractures.

An Anatomical Landmark for Retromandibular Transparotid Approach to Treat Subcondylar Fractures

ABSTRACT

Although the retromandibular transparotid approach (RTA) has been widely used to treat mandibular subcondyle fractures, the transient facial nerve injury (FNI) caused by this approach is not uncommon. The purpose of this paper was to present an anatomical landmark for RTA to treat subcondylar fractures, aiming to minimize FNI caused by the surgery. A total of 25 patients with subcondylar fractures but no FNI underwent RTA surgery. Intraoperatively, the plane of angulus oris was utilized as a reference to open the parotid and masseter tissues for exposing the fracture site. Postoperatively, FNI and other surgical complications were counted. The results showed that except for 2 cases of hematoma, no FNI or other complications occur. As a conclusion, utilization of plane of angulus oris as a reference for RTA to treat subcondylar fractures might make the surgery safer and less invasive.

The Stability Evaluation of Two Internal Fixation Patterns of Extracapsular Condylar Fracture Based on One Novel Measuring Method

PURPOSE

The most stable internal fixation pattern for extracapsular condylar fracture (ECF) has been controversial. In this study we aimed to evaluate the stability of 2 common internal fixation patterns using 1 or 2 miniplates separately. One novel measuring method based on the angle of miniplates' localization was introduced.

MATERIALS AND METHODS

Twenty-seven patients with 30 sides of extracapsular condylar fracture were enrolled in this retrospective study. All cases were performed open reduction and internal fixation using 1 or 2 titanium plates with both the postoperative immediate CT (T1) and the over 6 months' follow-up CT (T2). Mandibles and implants were segmented and reconstructed respectively using SIMPANT 14.04 software. For 1 miniplate group, the sagittal crossing angle (<1) between miniplate (P1) and posterior border of ipsilateral ramus was measured. For 2 miniplates group, the sagittal crossing angle (<2) between 2 miniplates (P2a, P2b) was measured. Both anteroposterior (∠AP) and mediolateral angle change (∠ML) of each miniplate between T1 and T2 was measured. The stability of 2 internal fixation patterns was measured and evaluated based on the angle change of miniplates. And also the stability of each internal fixation pattern could be investigated based on the relationship between the placement patterns of miniplates and the angle change.

RESULTS

Fifty-two miniplates were finally segmented and reconstructed successfully, including 8 of 1 miniplate group and 44 of 2 miniplate group. For 1 miniplate group, the average ∠AP and ∠ML were 6.10° and 8.54°, respectively. For 2 miniplate group, the average ∠AP and ∠ML of P2a were 3.02° and 2.56°, respectively, as well as 3.12° and 3.07° of P2b.

CONCLUSIONS

The novel measuring method based on the angle of miniplates' localization showed potential for the stability evaluation of internal fixation of condylar fracture. In summary, the internal fixation patterns using 2 miniplates shows better stability than that of 1 miniplate.

Evaluation of Open Reduction and Internal Fixation of Mandibular Condyle Fracture by Intraoperative Cone-Beam Computed Tomography in a Hybrid Operating Room

Condylar fractures are the most common fractures of the mandible, and treatment of mandibular condylar fractures by maxillofacial surgeons is a very important procedure. However, the surgical approaches have anatomical limitations. Therefore, it is difficult to evaluate the reduction achieved in open reduction and internal fixation because of the uncertainty in securing a sufficient operative field. As a potential solution, the authors evaluated the benefits of intraoperative cone-beam computed tomography (CBCT) with high image quality performed in a hybrid operating room. Intraoperative CBCT is easy to perform in a hybrid operating room, and it is possible to quickly evaluate high-quality CT images, including 3D images. Because the state of reduction of mandibular condylar fractures also affects the prognosis of treatment, more precise reduction and fixation should improve prognoses. The use of CBCT in a hybrid operating room also avoids re-operation, and patients benefit from minimum invasive surgery. Intraoperative CBCT is a very useful strategy for evaluation of mandibular condylar fracture surgical treatment.

A mechanical study of novel additive manufactured modular mandible fracture fixation plates - Preliminary Study with finite element analysis.✰

The paper presents an innovative osteofixation system designed for bone fracture stabilization. Its special feature, which makes it different from other similar systems, is the possibility to precisely adjust the implant to the shape of the bone. Such a precise adjustment is particularly important in the case of multiple fractures, where proper stabilization is a condition for restoring bone geometry and thus obtaining the biomechanical function of a given segment of the body lost due to fracture. Based on the tested properties of the implant material, the presented system structure was verified for loading, stress, and share forces in multi-site fractures of the mandible. Numerical tests were performed for three different fracture models: unilateral double fracture of the body of mandible, unilateral double fracture of the body and the angle of mandible, and bilateral fracture of the mandible at the angle and body of the mandible. The results indicate that the proposed system may be used to stabilize broken bone fragments successfully, and the obtained stabilization would allow unrestricted use of the chewing function during bone healing and remodeling. The authors point out the advantages of the proposed implantation method thanks to which it is possible to obtain any shape of the implant and thus stabilize bone fragments in any case.

Biomechanical Loading Comparison between Titanium and Unsintered Hydroxyapatite/Poly-L-Lactide Plate System for Fixation of Mandibular Subcondylar Fractures

Osteosynthesis absorbable materials made of uncalcined and unsintered hydroxyapatite (u-HA) particles, poly-l-lactide (PLLA), and u-HA/PLLA are bioresorbable, and these plate systems have feasible bioactive osteoconductive capacities. However, their strength and stability for fixation in mandibular subcondylar fractures remain unclear. This in vitro study aimed to assess the biomechanical strength of u-HA/PLLA bioresorbable plate systems after internal fixation of mandibular subcondylar fractures. Tensile and shear strength were measured for each u-HA/PLLA and titanium plate system. To evaluate biomechanical behavior, 20 hemimandible replicas were divided into 10 groups, each comprising a titanium plate and a bioresorbable plate. A linear load was applied anteroposteriorly and lateromedially to each group to simulate the muscular forces in mandibular condylar fractures. All samples were analyzed for each displacement load and the displacement obtained by the maximum load. Tensile and shear strength of the u-HA/PLLA plate were each approximately 45% of those of the titanium plates. Mechanical resistance was worst in the u-HA/PLLA plate initially loaded anteroposteriorly. Titanium plates showed the best mechanical resistance during lateromedial loading. Notably, both plates showed similar resistance when a lateromedially load was applied. In the biomechanical evaluation of mandibular condylar fracture treatment, the u-HA/PLLA plates had sufficiently high resistance in the two-plate fixation method.