Stability of Angle Fracture Fixation With (K) Shaped Titanium Miniplates Versus Two Miniplates

In the past two decades, rigid internal fixation with miniplate has become the standard treatment modality in the management of mandibular fracture.

The optimal management of mandibular angle fractures remains controversial, thus continuous experimental \& clinical studies are being conducted to determine the best miniplate design which will provide the best postoperative stability \& resistance to mechanical function.

Since Michelet et al.\& Champy et al. recommended the use of a single (4-6 holes) monocortical plate , it become an acceptable method for angle fractures fixation.

Several surgeons have documented low complication rates with (Champy technique).But, according to the most recent experimental \& clinical studies, the stability provided by the miniplate fixation has become a point of debate among surgeons.Many researchers have argued that internal fixation with a passive miniplate along the external oblique line, following Champy's ideal osteosynthesis line principle, produces a tension effect that may yield a failure of osteosynthesis \& gap at inferior border of the mandible.And that pushed researches to conduct more studies to evaluate many plate \& screw systems and even suggest new designs for better stable postoperative results.

In 2014, B.T.Suer et al, designed a new noncompression 3D miniplates , basically it has one straight section and two lateral extensions. The straight section of this new design, which has four holes, was adapted to the superior border of the external oblique ridge \& provides similar advantages to the Champy technique (an intraoral approach, a single miniplate, \& the use of monocortical screws) .And the two lateral extensions, with one hole each, were then bent over to adapt to the buccal cortex of the ascending ramus along the external oblique ridge to resist lateral \& torsional forces.

Fresh, frozen cadavers of 15 healthy sheep were obtained for this study, sheep were used in this study owing to the similarities in size \& thickness to the human mandible. All of the mandibles were stripped of their soft tissues \& sectioned through the midline, between the central incisors. 30 hemimandibles were randomly divided into two groups , these groups were then fixed with two different plating techniques (the new design \& one conventional miniplates). And they were all examined for stability and resistance to mechanical forces (vertical, lateral, or tensile).

The driving force behind this study was to design a new plate that would overcome the disadvantages of the other plating techniques but has the advantages \& simplicity of the Champy technique (simple intraoral approach and few major complications). This new miniplate gives more biomechanical stability than the conventional Champy plate. These findings are correlated to those of in vitro biomechanical study done by Alkan et al. that showed that Champy technique has less favourable biomechanical behaviour than biplanar fixation and 3D strut plate. In addition the new plate provide greater stability when subjected to lateral displacing forces.

More over the placement of a 3D miniplate or two separate miniplates for fixing angle fractures is more difficult and mostly will require a transbuccal approach , with increased surgical trauma, longer operation time unlike the new plate that could provide the clinician with a simple and reliable solution.