A new 3-dimensional plate for transoral endoscopic-assisted osteosynthesis of condylar neck fractures.

PURPOSE: Transoral surgical treatment of condylar neck fractures minimizes the risk of damaging the facial nerve. But fracture reduction and plate osteosynthesis remain challenging, especially when using 2 plates, although endoscopic assistance has proven helpful. To further improve and simplify osteosynthesis at the condylar neck, a new delta-shaped osteosynthesis plate that mimics the function of 2 plates has been developed. The present clinical follow-up study was conducted to evaluate this new plate. PATIENTS AND METHODS: A total of 16 patients with 19 condylar neck fractures (3 Spiessl I, 13 Spiessl II, 1 Spiessl III, 2 Spiessl IV) and 3 bilateral fractures were treated through an endoscopic-assisted transoral approach. After reduction, the plate was applied, with the screws inserted either transcutaneously or with angulated instruments. RESULTS: The operation time ranged between 55 and 120 minutes. More than 6 months after the operation, functional parameters returned to normal, with an average mouth opening of 41 mm, protrusion of 5 mm, and laterotrusion of 6 mm. Radiographic controls showed good fracture alignment in 15 of 19 cases immediately after the operation, and in 14 of 19 cases 6 months after the operation. No plate fracture or bending was observed. In 3 patients, loose screws were found on plate removal. CONCLUSIONS: The clinical data and the engineering and biomechanical background suggest that the new delta-shaped plate can be regarded as 2 miniplates. The new plate is suitable for treatment of condylar neck fractures, particularly when used in an endoscopic-assisted transoral approach.     

Miniplate osteosynthesis for fractures of the edentulous mandible: A clinical study 1989–96

Our 8 years experience of treating fractures of the edentulous mandible by miniplate osteosynthesis, is discussed. Forty patients (31 men and 9 women) aged 37 to 86 years (mean: 64.6 years, SD: +/- 14.07) with 67 fracture sites were treated. The surgical approach was mainly intraoral (37 out of 40 patients) without the use of intermaxillary fixation. The postoperative clinical and radiological findings are reported and discussed. The advantages of the method are of great importance since immediate postoperative opening of the mouth is permitted, as the fractured bones are anatomically stabilized by means of titanium miniplates and screws. Our results were felt to be satisfactory, with a reoperation rate of only 3.9% (two out of 51 operated fracture sites, 16 condylar fractures were treated conservatively). This allows us to propose intraoral miniplate osteosynthesis as a routine method of treatment in cases of edentulous mandibular fractures which are mainly seen in elderly people.     

Miniplate osteosynthesis for fractures of the edentulous mandible: A clinical study 1989–96

Our 8 years experience of treating fractures of the edentulous mandible by miniplate osteosynthesis, is discussed. Forty patients (31 men and 9 women) aged 37 to 86 years (mean: 64.6 years, SD: ± 14.07) with 67 fracture sites were treated. The surgical approach was mainly intraoral (37 out of 40 patients) without the use of intermaxillary fixation. The postoperative clinical and radiological findings are reported and discussed.The advantages of the method are of great importance since immediate postoperative opening of the mouth is permitted, as the fractured bones are anatomically stabilized by means of titanium miniplates and screws. Our results were felt to be satisfactory, with a reoperation rate of only 3.9% (two out of 51 operated fracture sites, 16 condylar fractures were treated conservatively). This allows us to propose intraoral miniplate osteosynthesis as a routine method of treatment in cases of edentulous mandibular fractures which are mainly seen in elderly people.     

Miniplate osteosynthesis of fractures of the edentulous mandible

This study was performed to analyze treatment of fractures of the edentulous mandible and to discuss this method in relation to the mandibular height at the fracture site. Fifteen fracture sites in 11 patients with an edentulous mandible were retrospectively examined. These fractures were located: nine fractures in the mandibular body, three in the paramedian region, and three in the mandibular angle. Fractures in a mandible measuring more than 10 mm in the vertical height were treated with one miniplate. Fractures in an extremely atrophic mandible with 10 mm or less were treated using one or two miniplates, also using a modified Champy plate with 1.3 mm in thickness. A mandibular fracture with a height of 5 mm was treated with a combination of a microplate on the buccal side and a miniplate on the inferior border of the mandible with additional direct circumferential wiring. Oblique or splitting fractures were treated with direct circumferential wiring or a Herbert screw, at one fracture site each, respectively. Complications, including infection, fibrous union, nonunion and trismus, were not seen. In one patient, hypesthesia of the lower lip was, however, persistent 1 month after surgery. Miniplate osteosynthesis is the less invasive treatment, and it is suitable for fractures of the atrophic edentulous mandible, except for comminuted or defect fractures. To obtain stable fixation in severely atrophic mandibles, we need to consider the use of two miniplates or a combination with microplates.     

Transoral miniplate osteosynthesis of condylar neck fractures.

OBJECTIVE: In a retrospective study, we reviewed a series of 55 consecutive patients with 57 fractures of the condylar neck that were treated with transoral miniplate osteosynthesis. STUDY DESIGN: Forty-one patients were included in a clinical follow-up study; the median length of study was 26.5 months (minimum, 7 months; maximum, 79 months). In a radiographic study, the positions of the condyle before open reduction, after open reduction, and more than 6 months postoperatively were evaluated in 3 radiographic planes. A statistical analysis was performed to determine factors that lead to secondary instability of the reduced condyle and to correlate the actual position of the condyle with clinical parameters collected in follow-up examinations. RESULTS: At the time of the follow-up examination, the median measurement of the mandibular openings was 48.3 +/- 8.0 mm (minimum, 32 mm; maximum, 66 mm). A deviation of 2 mm to the operated side when opening was observed in 7 patients. The median range of laterotrusion was 10.0 mm to the fracture side and 9. 0 mm to the opposite side. In 7 patients, radiographic follow-up more than 6 months postoperatively revealed a medial tilt of the proximal fragment of 15 to 40 degrees despite a good immediate postoperative position of the condyle. This may be attributed to bone resorption in the fracture gap, together with a bending instability observed when titanium miniplates with a thickness of 0. 9 mm were used. The position of the condyle at the follow-up examination did not correlate with clinical parameters. CONCLUSIONS: Transoral approach miniplate osteosynthesis of dislocated condylar neck fractures is indicated when visible scars in the head and neck region, which are encountered with other fixation techniques, must be avoided.     

A comparative evaluation of different treatment modalities for parasymphysis fractures: a pilot study

Maxime Champy advised the use of two miniplates for parasymphysis fractures because of the high torsional forces in the anterior region of the mandible. According to him there is no need for intraoperative or postoperative intermaxillary fixation, but most surgeons use arch bars for intraoperative or postoperative intermaxillary fixation. This study evaluated the role of the lower arch bar as a tension band eliminating the need for an upper miniplate (tension band plate) in cases of parasymphysis fractures. 3 groups underwent treatment. In the first group, two titanium miniplates were placed across the fracture site along with Erich's arch bar for 6 weeks. In the second group, two titanium miniplates were used for osteosynthesis without Erich's arch bar. In the third group, one titanium miniplate was placed along with Erich's arch bar for 6 weeks. The results of third group were statistically non-significant compared with those of the first and second groups.     

Biomechanical comparison of plating techniques for fractures of the mandibular condyle

We compared the biomechanical behaviour of various rigid internal fixation techniques for treatment of fractures of the mandibular condylar process. Fifteen sheep hemimandibles were used to evaluate three bicortical plating techniques. A custom-made 3-point biomechanical test model was used for the samples. Each group was tested with compression forces by an Instron Lloyd LRX machine. The resistance to forces (N) that caused displacements of 1.75 and 3.50mm were compared using the Instron software programme and displacement graphics. There were no significant differences among the three groups for displacements of 1.75 and 3.50mm. Our study showed that the titanium miniadaptation plates, minicompression plates, and the absorbable miniplates did not differ significantly in their biomechanical behaviour.     

Biomechanical evaluation of different types of rigid internal fixation techniques for subcondylar fractures.

PURPOSE: The aim of this study was to evaluate the biomechanical stability of various internal fixation systems for subcondylar fractures. MATERIALS AND METHODS: Eighteen identical synthetic mandibles were used. Left condylar processes were cut to mimic perpendicular subcondylar fracture and right sides were mimicked oblique subcondylar fracture. The fixation systems used included single 4-hole mini adaptation plate, double fixation with the same plates, single 4-hole mini dynamic compression plate (DCP), Eckelt lag screw system, Wurzburg lag screw plate system and double 4-hole biodegradable miniplates made of poly L-lactide (PLLA). In oblique fractures, one of the screws fixing plates was used bicortically through bone fragments. The loading vector simulated physiologic forces to the condyle on biting with servohydraulic testing machine until failure was reached. Load-displacement curve, maximum load for failure, and stiffness were measured. RESULTS: In perpendicular fracture, double adaptation plate showed the highest level of tolerance load followed by Eckelt lag and double PLLA plate. In stiffness, double adaptation plate and Eckelt lag screw showed higher level of stiffness, whereas double PLLA was almost at the same level of single DCP. In oblique fracture, double adaptation plate showed the highest strength. CONCLUSIONS: In this laboratory setting, double adaptation plates fixation proved to have superior biomechanical stability in both fracture conditions. Eckelt lag screw showed good stability in the perpendicular fracture, however, it was weak in the oblique fracture.     

Transorale operative Therapie von Kiefergelenkfrakturen mit einer 3D-Platte

Aim

The transoral approach minimizes the risk of damaging the facial nerve. However, stable osteosynthesis with two miniplates at the proximal fragment is often not possible. To achieve a stable fixation also of condylar neck fractures a new delta-shaped plate was developed, which meets the biomechanical demands of this region. This plate was tested in a clinical study.

Patients and methods

In total 11 patients suffering from 13 condyle fractures (Spiessl I: n?=?2, Spiessl II: n?=?10, Spiessl III: n?=?1, 3 bilateral fractures) were treated via a transoral approach and assessed clinically as well as radiologically in the follow-up period. Functional parameters and fracture alignment were assessed.

Results

After 6 months postoperative function had returned to normal with a mouth opening of 42 mm and pro- and laterotrusion of more than 5 mm. Postoperative radiographic controls showed a good fracture alignment in 7 of 8 patients respectively in 6 of 8 cases after 6 months. In 12 of 13 fractures directly postoperative and in 10 of 13 fractures 6 months postoperative, respectively, Towne's view radiographs showed an anatomical correct position. No plate fracture and no bending of plates were observed. Loosening of screws was found in 2 patients during plate removal.

Conclusion

The newly developed three-dimensional plate was easy to handle, and a sufficiently stable osteosynthesis of condyle fractures was possible. This plate can be recommended for surgical fracture treatment via a transoral approach omitting extraoral scars and damage to the facial nerve.     

翼外肌-髁突解剖复位内固定治疗髁突骨折的探讨

目的:探讨髁突骨折进行解剖复位和小型钛板坚强内固定的手术适应证、方法和治疗效果。方法:以髁头脱位骨折、髁颈和髁颈下骨折移位角度大于30°～45°、下颌支垂直高度降低超过4～5mm为适应证,对收治的23例28侧髁突骨折患者采用改良耳颞部"拐杖"型切口或颌后进路,行翼外肌-髁突解剖复位及张力带小型钛板坚强内固定。术后3～6个月复诊,检查面型、开口度、开口型、咬合关系、咀嚼力,并以此进行疗效评价。结果:所有患者面型对称,开口度较术前明显增大,开口型显著改变。2例术后错牙合患者经1周颌间牵引,恢复正常。影象学检查示髁突无移位,骨折无错位。钛板无移位,髁突表面无明显吸收现象。患者咀嚼有力。2例面瘫患者经治疗后3个月恢复。结论:选择合适病例,进行翼外肌-髁突开放性解剖复位固定,是一种既能恢复解剖形态又能恢复咀嚼功能的有效方法。     

Combination of microplate and miniplate for osteosynthesis of mandibular fractures: an experimental study

Because of the limited space available in the mandible, especially in the mental foramen and apical region, miniature osteosynthesis material is desirable. Recently, metal deposition in the direct neighbourhood of osteosynthesis plates made of titanium or even in peripheral organs have been reported in the literature with increasing frequency. The size and amount of osteosynthesis material used should therefore be kept to a minimum. In an experimental study on 60 models, we examined load-carrying stability and in a second series, torsional strength of two-piece plastic models connected by either a single miniplate, two miniplates, or a titanium microplate plus a miniplate. In our test arrangement, the average loading capacity of the combination miniplate/miniplate was 470 N: that of the combination microplate/miniplate was only 267 N. The test group with the single miniplate had an average loading capacity of only 225 N. Masticatory loads on the plates exceeding 200 N occur only 3 months after osteosynthesis. At that time the fracture has largely consolidated. The torsional strength of the microplate/miniplate combination was similar to that of the miniplate/miniplate combination (1,000 Nmm resulting in a width of the gap measuring 0.8 mm and 0.5 mm, respectively). The single miniplate was considerably less stable (0.8 mm gap width as early as with 300 Nmm). According to Champy, rotational forces in the anterior region of the mandible amount to approximately 1,000 Nmm and need to be withstood by the osteosynthesis material. Our results suggest that treatment of fractures in the interforaminal region with a combination of microplate and miniplate will be stable enough for early mobilization.     

Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle

The most stable pattern of internal fixation for fractures of the mandibular condyle is a matter for ongoing discussion. In this study we investigated the stability of three commonly used patterns of plate fixation, and constructed finite element models of a simulated mandibular condylar fracture. The completed models were heterogeneous in the distribution of bony material properties, contained about 1.2 million elements, and incorporated simulated jaw-adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. This model was considerably larger and more complex than previous finite element models that have been used to analyse the biomechanical behaviour of differing plating techniques. The use of two parallel 2.0 titanium miniplates gave a more stable configuration with lower mean element stresses and displacements over the use of a single miniplate. In addition, a parallel orientation of two miniplates resulted in lower stresses and displacements than did the use of two miniplates in an offset pattern. The use of two parallel titanium plates resulted in a superior biomechanical result as defined by mean element stresses and relative movement between the fractured fragments in these finite element models.     

Stability of bioresorbable plates following reduction of mandibular body fracture: Three-dimensional analysis

PurposeThe recent development of bioresorbable bone plates and screws allows plates to be applied to the load-bearing regions of the mandible and to remain in place over time without the need for removal. We hypothesized that the stability of composite plates and screws forged from unsintered hydroxyapatite particles and poly-l-lactide (u-HA/PLLA) is comparable to that of standard titanium fixation systems for the reduction of fractures of load-bearing regions of the mandibular body.Materials and methods40 patients underwent open reduction and internal fixation of the fractured mandibular body with either a titanium or u-HA/PLLA bone plate. Cone-beam CT images were obtained immediately postoperatively and at 6-month follow-up, and were analyzed for positional changes of the affected mandible.ResultsThere were no significant differences in the postoperative positional changes of reference points between the titanium and u-HA/PLLA miniplates, except for that for the coronoid process (p-value = 0.03). Multivariate regression analysis revealed no significant differences in spatial changes between the immediate postoperative and 6-month follow-up images, after adjusting for age and sex.ConclusionThe stability of bioresorbable u-HA/PLLA miniplates and screws was comparable to that of titanium miniplates and screws immediately postoperatively and at 6-month follow-up, following surgical reduction of fractures of load-bearing regions of the mandibular body. Bioresorbable osteosynthesis can be considered a viable alternative to titanium osteosynthesis.     

Clinical evaluation of 3 types of plate osteosynthesis for fixation of condylar neck fractures.

PURPOSE: The goal of this study was to evaluate outcomes in patients who had condylar neck fractures treated with 3 different plating techniques. PATIENTS AND METHODS: A retrospective study was performed on 37 patients with 40 fractures of the condylar neck that were reduced and stabilized using an approach involving exposure of the facial nerve. Stabilization was achieved with a single miniplate (17 fractures), a minidynamic compression plate (13 fractures), or double miniplates (10 fractures). RESULTS: Plate fracture or screw loosening was exclusively observed in cases stabilized with either a single miniplate or a minidynamic compression plate. No cases of inadequate stability were observed when 2 miniplates were used. CONCLUSIONS: The 2-miniplate fixation technique provides functionally stable fixation for fractures of the condylar neck.     

Mandibular osteosynthesis by miniature screwed plates via a buccal approach.

The modified Michelet's (1973) technique of mandibular osteosynthesis, which consists of monocortical juxta-alveolar and sub-apical osteosynthesis, without compression and without inter-maxillary fixation, is described. This technique can be used in many types of mandibular fracture, single or multiple, associated or isolated, except in the case of a fracture of the condylar neck and in the presence of pre-existing infection. Infected fractures are treated by orthopaedic methods. Materials used (plates and screws) and particulars of the method have been tested by multi-disciplinary experimentation, particularly by anatomical verification and biomechanical studies. The ideal line of osteosynthesis is described. For the author, this technique is a routine treatment of any type of mandibular fracture.     

“A” shape plate for open rigid internal fixation of mandible condyle neck fracture

IntroductionReduction of the fracture is crucial for proper outcome of the treatment. The stability of reduction is closed connected to the method of its fixation. The topic of condylar fracture osteosynthesis still remains highly controversial and challenging. That is why authors decided to propose novel design of the fixating plate and the example of its application. The aim of this study was to present A-shape plate dedicated to rigid fixation of mandible condyle neck fracture.Material and methodsA-shape condylar plate (ACP) design is prepared of 1.0 mm thick titanium alloy (grade 5) sheet: posterior and anterior bars are reinforced by widening to 2.5 mm and anatomically curved along the compression and traction lines in ramus and condylar neck. Superior three-hole-group has triangular organization and located on the level of condylar head. The inferior extensions of the bars are equipped in three holes located at each of lower tails. Connecting bar (2.0 mm wide) connects the first hole of each lower tails closing upper part of ACP in triangular shape. The connecting bar runs along compression line of condylar neck. Holes in ACP has 2.0 mm diameter for locking or normal screws. Height of ACP is 31 mm. The proposed new type of plate was compared by finite element analysis (FEA) to nowadays manufactured 9-hole trapezoid plate as the most similar device. ACP design was evaluated by finite element analysis (FEA) and later applied in patient affected with high condylar neck fracture complicated by fracture of coronoid process.ResultsFEA revealed high strength of ACP and more stabile fixation than trapezoid plate. The result was caused by multipoint fixation at three regions of the plate and reinforced bars supported by semi-horizontal connecting bar. Clinical application of ACP was as versatile as makes possible to simultaneous fixation of high condylar neck and coronoid process fracture.ConclusionApplication of proposed A-shape condylar plate would be possible in all levels of neck fractures and can be use for stabilization additionally existed coronoid process fracture.     

Single Miniplate Fixation for Mandibular Symphysis and Parasymphysis Fracture as a Viable Alternative to Conventional Plating Based on Champy’s Principles: A Prospective Comparative Clinical Study

To compare long term and short term outcomes of fixing mandibular symphysis and parasymphysis fractures with single mini plate and conventional fixation using two mini plates. Study design: in this prospective clinical comparative study, 30 patients with fracture in study region were randomly divided into two groups. Group A patients received single 2.5 mm titanium miniplate and Group B patients received two 2 mm titanium miniplates as per Champy's lines of osteosynthesis. Patients were followed up at intervals of 1, 12 and 24 weeks. Parameters assessed were: duration of surgery, fracture stabilization, paresthesia, occlusion and wound dehiscence. Statistically significant difference was observed in mean duration of surgery and wound dehiscence (P < 0.05). No significant difference was observed with respect to other parameters. Single 2.5 mm miniplate for mandibular symphysis and parasymphysis fractures is a time saving and cost effective technique with post-operative outcomes similar to conventional 2 plate fixation.     

Evaluation of condylar neck fracture plating techniques.

The purpose of this study was to compare the biomechanical stability of four different plating techniques used to fix condylar neck fractures and to decide which fixation systems are strong enough to withstand the functional load. Ten recently acquired formalin-fixed cadaver mandibles were used for this study. Each of the four sets of osteotomized condylar processes was fixed by one of four different fixation systems. The mandibles were then held in an angle vice so that the mandibles were oriented to simulate actual masticatory force loading on the temporomandibular joint and were loaded with an Instron loading machine. Data demonstrated that a two-miniplate system applied to the anterior and posterior regions of the condylar neck was more stable than single-plate repairs using either mini-dynamic compression plates or 2.4 mm plates. The two-miniplate-fixation technique is indicated in cases of condylar neck fracture to achieve early mobility of the jaw and stability of the fracture site.     

Development and biomechanical testing of a new osteosynthesis plate (TCP) designed to stabilize mandibular condyle fractures.

INTRODUCTION: In this paper, the different steps of development and experimental validation of a new type of three-dimensional (3-D) trapezoidal osteosynthesis plate (Modus TCP 2.0, Medartis, Basel, Switzerland) is described. These plates have been designed to stabilize sub-condylar and condylar neck fractures of the mandible. MATERIAL AND METHODS: In order to apply the principles of functionally stable osteosynthesis to the mandibular condyle, i.e. to put the plate as close as possible to the tensile strain lines occurring during function, two new 4- and 9-hole 3-D trapezoidal plates were designed. Tests were conducted on fresh human mandibles before and after osteosynthesis of a standardised unilateral sub-condylar 'fracture', and a static biting exercise between the ipsilateral first molars was reproduced on a test bench. The resulting condylar fragment displacement in the sagittal plane was measured and the alterations of the condylar tensile strain lines induced by the osteosynthesis were investigated by using photoelastic strain tests. RESULTS: None of the plates broke. No macroscopic condylar displacement was noted when assessing the quality of the primary stabilization. Strain analysis showed the ability of these 3-D plates to transmit physiological strains across the fracture line and the absence of potentially damaging strains around the plate. DISCUSSION: These results were accredited to the 3-D and trapezoidal features of the plates. CONCLUSION: The Modus TCP plates experimentally fulfil the principles of functionally stable osteosynthesis in the condylar region and are able to resist physiological strains.     

Biomechanical study on monocortical osteosynthesis for the fracture of the mandible

In order to compare the rigidity of the fixation and resultant bone healing of monocortical versus bicortical osteosynthesis, biomechanical tests were performed in dogs. Use of a gnathotome made it possible to produce a mandibular fracture with minimal bone defect between fragments. An AO dynamic compression plate and a mini-plate were used for the fixation of each half side of the fractured mandible. The biomechanical tests revealed that bicortical osteosynthesis was superior to monocortical in the rigidity of the fixation. However, the results after removal of the plates, at 14 weeks postoperatively, showed that there was no apparent difference between the 2 sides. Monocortical osteosynthesis is useful in the treatment of mandibular fractures, except for fractures with bone defects, comminuted fragments and laceration of the lateral cortical bone.