Introduction

A mandibular condyle fracture comprises 25 to 45% of all mandibular fractures [ 1 - 2 ]. Direct and indirect forces in the condylar region most commonly cause unilateral or bilateral subcondylar fracture [ 3 ]. Anatomically, the mandible dissipates the forces to the condylar neck, which is more susceptible to fracture, and therefore prevents forces from being transferred to the cranium. This increases the frequency of mandibular condylar fracture [ 4 ].

The narrow bone anatomy in the condylar neck does not often provide the necessary surfaces for positioning of multiple hardware according to the stress lines. The stresses in the thin condylar neck area increase significantly in comparison to the broader condylar base. Stable three-dimensional fixation is very important as this may lead to non-union, fibrous union, or temporomandibular disorders from interfragmentary mobility [ 5 - 6 ].

3D Delta plates have been designed to adapt to and neutralize strain during ORIF of condylar fractures and have the advantage of being smaller in size. The aim of this study was to address the efficiency of the delta plate for the fixation of the condylar fracture.

Case Presentation

In this retrospective review, we did a case series of condylar fractures on 10 patients where all patients had clinical symptoms including deranged occlusion, reduced interincisal distance, and restricted mandibular movements. All the patients were treated with ORIF using a delta plate. In all cases, preoperative and postoperative clinical and radiological examinations were done (Figure 1a and b). We diagnosed the condylar fractures with the help of orthopantomogram and computed tomography scan preoperatively. We have also measured the dimensional details of the anteroposterior width of the condylar neck, on 10 dry human mandibles and also the dimensional details of the plate (Figures 2 and 3). The measurement details were used for preoperative assessment in treatment planning. Simulation of these measurement details was done with the computed tomography scan with the help of Radi-Ant DICOM Viewer software (v2021.1) (Figure 4).

Figure 1.a: Preoperative ct scan in axial, coronal and sagittal view. Retromandibular incision marked open reduction and internal fixation (ORIF) done with delta plate postoperative orthopantomogram, b: Preoperative orthopantomogram retromandibular incision marked. Open reduction and internal fixation (ORIF)done with delta plate postoperative orthopantomogram

Figure 2. Dimensions of condylar neck region measurement done with vernier calipers in the dry mandible

Figure 3. Dimensions of indigenous titanium delta plate

Figure 4.Dimensions of condylar neck region in computed tomography scan

The mandibular condyle was approached by a retromandibular incision in all patients. An ORIF of a condylar fracture using the triangular-shaped delta plate provides stability in three dimensions. In the delta plate, the lines of tensile and compressive stress distribution run parallel to both sides of the plate and the base is oriented toward the angle of the mandible. The plate consists of two longitudinally arranged holes at the top, and two more holes are located at the two corners of the base of the plate (Figures 5 and 6).

Figure 5. Indigenous titanium delta plate with four screws

Figure 6. Easy hypothesis for delta plate fixation

The surgical approach for the patients in the open reduction group was retromandibular. In all cases, delta plate was used for fixation at different levels of the condylar neck fracture. No postoperative occlusal derangement was noted. All patients had optimal jaw movement without any deviation. Postoperative radiographs showed satisfactory healing in all patients. After a 1-year follow-up period, there were no signs of screws loosening or secondary displacement of fractured segments.

In all the 10 cases, it showed acceptable results in relation to ramal height maintenance and proper angular reduction; though we feel a larger sample size would have provided a more reliable outcome to make a comment on (Table 1).

Discussion

According to Anirudhan et al. [ 7 ] and Lauer et al. [ 8 ], compressive and tensile stress lines run through the bone along both side of the delta plate. It has a cross-section of 1×2.5mm and finite element analysis shows the distribution of tensile strain along the anterior border of the delta plate.

The ease of positioning of delta miniplate and securing two screws through the vertically placed holes in the narrow region of the proximal segment is one of the major benefits of using it [ 9 ]. A delta plate does not interfere in the fracture healing process and practically, it is almost impossible for the plate to break or fail as a result of the loosening of the retaining screws [ 9 ]. With this design of the delta miniplate, it is possible to relieve the fracture segment of the condyle from any postoperative stress better than other mini plates, which allows for a faster healing and reduced complications after surgery [ 8 , 10 - 12 ].

Ganguly et al. [ 13 ] stated that compared to conventional mini plates, delta plates provide better results in terms of operating time, mouth opening, and biting efficiency. The geometry and the design of the plate provide better stability and it allows the implant to easily accommodate the anatomy of the fracture, resulting in minimal risks and complications intraoperatively. A week of immobilization was sufficient to allow for early rehabilitation and functional loading.

The study by Arjun Ahuja et al. [ 14 ] concluded that delta plates are superior from the perspective of handling, ease of adjustment, and takes less time for adaptation. It is also a cost-effective option from the patient’s perspective. The delta miniplate has the highest values (17.3 N/m) in terms of rigidity. In terms of posterior-anterior direction, the delta plate is considered as best. A specific geometry of the delta plate gives three-dimensional stability and optimal leverage [ 15 ].

In terms of hardware volume, delta miniplate has a noticeably smaller volume than other mini plates [ 10 ]. Strain in bone is remarkably high around the screws in the mesial fragment of the delta miniplate when compared to other mini plates [ 10 ]. The improvement in the protrusive movement of the mandible was found to be gradual and better in the delta miniplate than in other miniplates [ 16 ]. Evaluation of primary stability in the region of the fracture line is determined by the opportunity to take the stress from bone to plate and distribute it to numerous screws. Better distribution of tension throughout the plate and horizontal arrangement of screws in the distal segment provide better secondary stability in the area of fixation.

In our experience, the delta miniplate is easy to adapt in the condylar neck region with less operating time, more internal stability, less stress related to screws, and has an acceptable outcome. It can withstand muscular forces with stress concentration in the condylar neck region. Patient consent form was signed and taken from each of the patients.

Conclusion

Delta plate provides better stability due to its geometry and configuration at the condylar neck region. There are several advantages associated with this small profile osteosynthesis plate, including its ability to neutralize the changing strains at the lateral, anterior, and posterior borders and the fact that the base acts as a compression plate. This plating system is associated with very few complications but it also has some disadvantages such as the length of the delta plate and the adaptability with the curvature in the condylar neck region.

Acknowledgment

Written informed consent was obtained from the patients for publication of this research article and accompanying images.

Conflict of Interest

The authors declare that they have no conflict of interest.

References

1. Gassner R, Tuli T, Hächl O, Rudisch A, Ulmer H. Craniomaxillofacial trauma: a 10 year review of 9543 cases with 21 067 injuries. J Craniomaxillofa Surg. 2003; 31: 51-61.
2. Stacey DH, Doyle JF, Mount DL, Snyder MC, Gutowski KA. Management of mandible fractures. Plastic Recons Surg. 2006; 117: 48e-60e.
3. Hakim SG, Wolf M, Wendlandt R, Kimmerle H, Sieg P, Jacobsen HC. Comparative biomechanical study on three miniplates osteosynthesis systems for stabilisation of low condylar fractures of the mandible. British J Oral Maxillofac Surg. 2014 1; 52: 317-322.
4. Dayi E, Omezli MM. Review of biomechanical experimental studies on different plating techniques of mandibular condyle fractures. Annals Maxillofac Surg. 2011; 1: 48.
5. Murakami K, Yamamoto K, Sugiura T, Horita S, Matsusue Y, Kirita T. Computed Tomography–Based 3-Dimensional Finite Element Analyses of Various Types of Plates Placed for a Virtually Reduced Unilateral Condylar Fracture of the Mandible of a Patient. J Oral Maxillofac Surg. 2017; 75: 1239-1241.
6. Bhowmick RS, Bhowal K, Ghosh S. Plating systems for 3D stability of subcondylar fracture: A research article with review of literature. Int J Orthopaed. 2019; 5: 681-683.
7. Anirudhan A, Khalam SA, Zachariah RK. Evaluation of clinical use of indigenously developed delta plate in management of subcondylar fracture. Clin Prac. 2013; 3: 74-76.
8. Lauer G, Pradel W, Schneider M, Eckelt U. A new 3-dimensional plate for transoral endoscopic-assisted osteosynthesis of condylar neck fractures. J Oral Maxillofac Surg. 2007; 65: 964-971.
9. Sikora M, Sielski M, Stąpor A, Chlubek D. Use of the Delta plate for surgical treatment of patients with condylar fractures. J CranioMaxillofac Surg. 2016; 44: 770 -774.
10. Albogha MH, Mori Y, Takahashi I. Three-dimensional titanium miniplates for fixation of subcondylar mandibular fractures: comparison of five designs using patient-specific finite element analysis. J Craniomaxillofac Surg. 2018; 46: 391-397.
11. Meyer C, Martin E, Jean-Luc KA, Simone ZI. Development and biomechanical testing of a new osteosynthesis plate (TCP®) designed to stabilize mandibular condyle fractures. J Craniomaxillofac Surg. 2007; 35: 84-90.
12. Kozakiewicz M, Swiniarski J. "A" shape plate for open rigid internal fixation of mandible condyle neck fracture. J Craniomaxillofac Surg. 2014; 42: 730-737.
13. Ganguly A, Mittal G, Garg R. Comparison between 3D delta plate and conventional miniplate in treatment of condylar fracture: a randomised clinical trial. J Craniomaxillofac Surg. 2021; 49: 1026-1033.
14. Ahuja SA, Galinde J, Asnani U, Mistry YA. Comparative evaluation of clinical outcomes using delta plates and conventional miniplates for internal fixation of mandibular condylar fractures in adults. J Oral Maxillofac Surg. 2018; 76: 1255-1266.
15. Deshpande AD, Pandilwar P, Datarkar A. Delta plate- a better option for management of condylar fracture of mandible. Int J Current Adv Res. 2018; 7: 8808-8811.
16. Lata J, Verma N, Mahajan S. Evaluation of efficacy of 3-dimensional delta versus trapezoidal condylar plates in internal fixation of mandibular subcondylar fractures: a clinical study. Traumaxilla. 2019; 1: 11-21.