Miniplate System Research Articles

Use of Straight and Curved 3-Dimensional Titanium Miniplates for Fracture Fixation at the Mandibular Angle

The aim of this follow-up study was to evaluate the clinical usefulness of a new type of 3-dimensional (3D) miniplate for open reduction and monocortical fixation of mandibular angle fractures. In 20 consecutive patients, noncomminuted mandibular angle fractures were treated with open reduction and fixation using a 2 mm 3D miniplate system in a transoral approach. All patients were systematically monitored until 6 months postoperatively. Among the outcome parameters recorded were infection, hardware failure, wound dehiscence, and sensory disturbance of the inferior alveolar nerve. The mean operation time from incision to wound closure was 65 minutes. Two patients had a mucosal wound dehiscence with no consequences. None developed an infection requiring a plate removal. All but 2 patients had normal sensory function 3 months after surgery. Plate fracture occurred in one patient in whom a preceding surgical removal of the third molar had been the reason for the mandibular fracture. In the absence of clinical symptoms, the patient declined plate removal. On final follow-up, fracture healing was considered clinically complete in all patients. The 3D plating system described here is suitable for fixation of simple mandibular angle fractures and is an easy-to-use alternative to conventional miniplates. The system may be contraindicated in patients in whom insufficient interfragmentary bone contact causes minor stability of the fracture.

Evaluation of different miniplates in fixation of fractured human mandible with the finite element method

The objective of this study was to develop a 3-dimensional finite element model (FEM) to formulate biomechanical justification of the positioning of different plates to achieve stable fixation of a fractured mandible. Miniplate systems that give acceptable levels of rigidity were investigated, and recommendations about miniplate location, orientation, and type selection are made. A fracture near the body region was bridged with a variety of commonly used plate configurations. Number, positioning and type of the plate system parameters. The results of this fracture model support the advantage of 2-plate systems. Using a longer plate in the superior position and a shorter one in the inferior position produced a more stable condition. Number of screws or length of the miniplate had no significant effect on the stability of fractured segments. The results obtained from this study offer the choice of a particular plate size, thickness, design, or configuration for application and thus provide information for clinical use.

Mandibular Plate Removals and the Associated Risk Factors: A Retrospective Study

(Webb A)

Posterior cervical laminoplasty using a new plating system: technical note.

Laminoplasty is well described in the Japanese literature as a surgical option for treating ossification of the posterior longitudinal ligament (OPLL). The open door technique has gained increasing popularity in the United States and Europe to treat not only OPLL but also cervical stenotic myelopathy. An obstacle to its widespread use is the lack of a suitable fixation plate to adequately secure the fractured lamina to the lateral mass. Our objective was to demonstrate the advantages of a novel miniplate (Ti-Mesh LP system; Medtronic Sofamor Danek, Memphis, TN, USA) that is ideally suited for fixing the lamina to the lateral mass. We used the Ti-Mesh LP miniplate system to perform laminoplasties on five patients, all male, with a mean preoperative Nurick score of 2.8. Four patients had congenital cervical stenosis with myelopathy and one had OPLL. Open door laminoplasties were performed on all patients. The plates were implanted with a claw positioned on the trapdoor lamina and a flat plate on the lateral mass. The system was implanted successfully in all patients. The mean number of levels fixated was 4.4. There were no intraoperative or postoperative complications after >5 months follow-up. The new Ti-Mesh LP cranial miniplate and screw system facilitates posterior cervical laminoplasty procedures by eliminating the need to contour cranial miniplates for use in the cervical spine. Its unique claw construct and angled design are ideal for holding a trapdoor laminoplasty in the open position. We have used this system successfully and without complications to perform decompressive posterior cervical laminoplasties in five patients.

Resorbable poly- l-lactide plates and screws for the treatment of mandibular condylar process fractures: a clinical and radiologic follow-up study

Purpose The purpose of this study was to determine whether a resorbable poly- l-lactide (PLLA) miniplate system could be used to treat mandibular condylar process fracture. Patients and methods Fourteen patients (12 males, 2 females, aged 23.1 ± 5.7 years) who had mandibular condylar process fractures treated with PLLA implants were recalled for follow-up clinical and radiologic examinations at 3 years. Results Mouth opening recovered to more than 35 mm and occlusion was stable in all patients. There was no facial asymmetry 3 months postoperatively. Two patients had mild chronic postoperative tenderness at the implantation site; however, there was no wound infection. All fractured mandibular condyles showed anatomic good reduction and long-term stability with the use of resorbable miniplates and screws. Bone healing was satisfactory in all patients, and there was no evidence of abnormal resorption of the condylar process. The screw holes remained evident after 3 years. Screw holes in 2 patients showed enlargement on radiographic examination. Conclusion The PLLA miniplate system provides reliable stability when used for the fixation of mandibular condylar process fractures.

Self-reinforced bioabsorbable miniplates for skeletal fixation in complex hand injury: three case reports

We report our preliminary experience with 3 cases in which internal fixation with a self-reinforced poly- l/ dl-lactide 70/30 miniplate and 1.5-mm or 2.0-mm screws were used to stabilize an open metacarpal fracture, a metacarpophalangeal arthrodesis in a thumb replantation, and an interposed bone graft for reconstruction of a thumb. Clinical and radiologic follow-up evaluation lasted for 12 to 20 months. Bone healing was uneventful in all 3 cases with no displacement or delayed union. The implants were biocompatible with no clinically manifested foreign body reaction. Because of the self-reinforcing manufacturing technique the plates have metal-like mechanical and handling properties. Complete late resorption makes self-reinforced poly- l/ dl-lactide 70/30 miniplating systems an attractive alternative to metallic implants for skeletal stabilization of small bones of the hand.

Mandibular fractures in Townsville, Australia: incidence, aetiology andtreatment using the 2.0 AO/ASIF miniplate system

In 1995 a total of 114 patients presented with 154 mandibular fractures at the Townsville General Hospital, Australia. Fifty-eight (51%) were white, 50 (44%) aboriginal, and six (5%) of other or unknown race. One-hundred-and-twenty-four of the fracture<$>s (81%) occurred in male and 30 (19%) in female patients. Most fractures (n= 128, 83%) resulted from fights. The rest being a result of road traffic accidents (10%), falls (3%), accidents caused by falling objects (3%) and sport accidents (2%). The mandibular angle (n= 66, 43%) and the symphyseal area (n= 40, 26%) were the most common fracture sites. Combined fractures were found in 30% patients (26%). Of all angle fractures, 97% were related to third molars. One-hundred-and-five patients had open reduction by an intraoral approach and stabilization by 2.0 AO/ASIF titanium miniplates and nine closed reduction. Complications included temporary sensory deficit of the mental nerve (3%), minor malocclusion (2%) and infection or dehiscence (5%). We conclude that osteosynthesis of mandibular fractures by the 2.0 AO/ASIF titanium miniplate system is reliable.

Application of the Maxillofacial Mini-plate Compact 1.0 in the Fracture Repair of 12 Cats/2 Dogs

SummaryThis study reports the application of the AO/ASIF maxillofacial mini-plate system, Compact 1.0a (MF mini-plate 1.0), in the repair of fractures in 12 cats and two small sized dogs. The malleability of these titanium mini-plates allows them to be precisely contoured and positioned to fit onto the most advantages sites of the bone. Selftapping mini-screws provide an easy application and a time-saving osteosynthesis. Fractures of miniature bones too small for the regular AO/ASIF miniimplants can be repaired successfully with this MF mini-plate 1.0 implant set. The special indications reported were the repair of fractures of the angle of the mandible in cats, articular digital fractures in small dogs and the stabilization of small avulsion fractures in cats and dogs.This study shows the successful application of the titanium maxillofacial mini-plate, Compact 1.0, in 12 cats and two toy breed dogs. Miniature fractures, such as mandible or digit fractures, too small for the AO/ASIF mini-plate system are indications for these implants. The self-tapping screws of the maxillofacial system, Compact 1.0, with a core diameter of 0.7 mm, can be used as plate screws or interfragmentarily.

The resorbable miniplate system lactosorb in a growing cranio-osteoplasty animal model

In the surgical treatment of craniosynostosis and craniofacial dysostosis in the growing child, passive intraosseous translocation (PIT effect) with intracranial displacement of metal plates and screws may be a problem. In an animal experiment, a possible PIT effect using resorbable PLA/PGA miniplates (Lactosorb, W. Lorenz, FL, USA) following cranio-osteoplasty were investigated in four young Göttingen minipigs. In addition to the mechanical properties, the processes of degradation and of sub- vs supraperiosteal application of the miniplates were evaluated. During degradation the resorbable PLA/PGA miniplates performed like metal plates as they also displayed passive intraosseous translocation in the growing animal model. However, in the experimental PLA/PGA miniplating the internal calvarial bone was not affected. Degradation took 12-18 months and was not delayed by bony incorporation. Mechanical properties proved to be sufficient in craniofacial surgery. Supraperiosteal plating delayed the PIT effect during the first 3 months after surgery. In the growing skull resorbable plates seem to be a promising therapeutic approach. However, prior to a general recommendation results of long-term clinical studies have to be evaluated.

Complications of internal fixation of maxillofacial fractures with microplates

Purpose: The aim of this retrospective study was to evaluate the complications of open reduction and internal fixation of maxillofacial fractures with microplates. Patients and Methods: In 44 patients with maxillofacial trauma, fractures of the maxillofacial skeleton were treated by open reduction and internal fixation using a 1.0-mm and 1.5-mm microsystem. Simultaneously occurring fractures of the mandible or frontozygomatic suture were treated with a 2.0-mm miniplate system. Perioperative and postoperative complications were traced using patient charts, operation reports, and radiographs. The average follow-up was 46.8 months (range, 31 to 54 months). Results: A total of 124 1.0-mm microplates and 546 1.0-mm microscrews, and 17 1.5-mm microplates and 75 1.5-mm microscrews, was used. The perioperative complication rate was 1.2% for the 1.0-mm screws (use of four emergency screws, breakage of one screw in the dense frontozygomatic suture area, and an insertion of a screw in a premolar root). The postoperative complication rate was 0.8% for the 1.0-mm screws (screw dislocation without clinical implication). No complications were observed with the 1.5-mm system. Plate-related infection did not occur. All fractures healed well. Three patients asked for plate removal because of a vague, persisting pain in the treated area. After removal, only one patient was free of pain. A loose 1.5-mm screw was found in this patient. Conclusion: The overall complication rate for microsystems was 2.0%. Both microsystems proved to be a reliable modality to fix fractures of the maxillofacial skeleton. Complications can be considered incidental and of neglectable clinical significance.

Is there still a role for traditional methods in the management of fractures of the zygomatic complex?

With the introduction of low-profile mini-plating systems, a trend has developed towards open reduction and rigid internal fixation (ORIF) of fractures of the cranio-facial skeleton. The current policy for management of zygomatic fractures in our unit is to attempt primary reduction by traditional methods, and proceed to ORIF in the event of unsatisfactory fracture stability or alignment. Over a one-year period, 109 patients underwent surgical correction of fractures of the zygomatic complex. Standard Gilles' elevation was performed in 71 cases, percutaneous elevation in three cases, and ORIF was performed in 35 cases. Mean follow-up was 190 days. One case of persistent infraorbital step and three cases of residual malar flattening were documented in patients who underwent Gilles or percutaneous elevation. Morbidity associated with ORIF was minimal. We conclude that while ORIF of zygomatic fractures may offer better results than traditional methods in the management of complex fractures, traditional methods still have a role to play in less complex fractures.

A bioabsorbable poly-l-lactide miniplate and screw system for osteosynthesis in oral and maxillofacial surgery

A bioabsorbable poly-l-lactide miniplate and screw system for osteosynthesis in oral and maxillofacial surgery

A bioabsorbable poly-L-lactide miniplate and screw system for osteosynthesis in oral and maxillofacial surgery

Purpose: The purpose of this study was to evaluate the usefulness of a bioabsorbable poly-L-lactide (PLLA) miniplate system for osteosynthesis. Materials and Methods: Ultra-high-strength PLLA rods were fabricated using a drawing technique. This osteosynthesis system, consisting of bioabsorbable PLLA miniplates and screws, was used clinically on 50 patients. Results: The only postoperative complications were two cases of postoperative infection, but these were controlled by an oral antibiotic regimen or plate removal. Bone healing was satisfactory in all cases, without delay of bony union or obvious displacement of segments after surgery. Conclusion: The PLLA miniplates provided effective osteosynthesis of the maxillofacial skeleton.

Wurzburg lag screw plate versus four-hole miniplate for the treatment of condylar process fractures

Purpose : The purpose of this study was to compare the biomechanical stability of rigidly fixed condylar neck fractures using either a conventional four-hole miniplate system or the Wurzburg lag screw plate system. Materials and Methods : Ten identical synthetic mandibles were used for this study. Simulated bilateral condylar neck fractures were fixed with the lag screw plate system on one side and the miniplate system on the other. The mandibles were loaded with an MTS servohydraulic testing machine at a rate of 1 cm/min until failure was reached. Data for resistance to motion and ultimate strength for each fixation device were compared by paired Student t-tests. Results : The mean resistance to motion for the four-hole miniplate was 64.0 kg/mm (SD = 10.1; range = 52–94) and for the lag screw system was 80.2 kg/mm (SD = 24.0; range = 55 to 126). The mean failure strength was 4.0 kg (SD = 0.9) (range = 2.6 to 5.5) for the miniplate system and 5.0 kg (SD = 2.5; range = 3.4 to 7.2) for the lag screw system. The lag screw system was significantly ( P < .05) better than the miniplate for both parameters measured. Conclusion : In laboratory testing using synthetic mandibles, the Wurzburg lag screw-plate fixation system proved superior to a four-hole miniplate system in regard to resistance to motion and failure strength. Clinical trials are necessary to substantiate these laboratory data and determine whether the system can be effectively applied by the surgeon.

Tissue reaction around miniplates used for the fixation of vascularized iliac crest bone grafts

Material/Method. In six miniature pigs revascularized autologous iliac crest bone grafts were fixed with two 2.0 mm titanium miniplates to a defined defect in the angle of the mandible. Tissue reaction around the implants was examined histologically and histomorphometrically at 2, 4, and 8 weeks after surgery. Results. According to the evaluation of fluorescence microradiography, the cortical and medullary circulation and healing processes of bone in the vicinity of the implanted material were not disturbed after 2 weeks. At 4 weeks after surgery osseous healing occurred at the mandibula/graft interface. The histomorphometric results for the calculated percentage of direct bone/screw contact at 2 weeks were 24% with the grafted bone and 53% with the mandible. Intensive bone formation was observed in all parts of the graft by 4 weeks. The results of direct bone/screw contact at 4 weeks were 56% and 64% and at 8 weeks 75% and 77% for the grafted and the mandibular bone, respectively. Conclusion. With 2.0 mm titanium miniplates used in the animal model, stable osteosynthesis and osseous healing was evident after 8 weeks of surgery. In addition, intensive remodeling of the transplanted bone without signs of creeping substitution was noted, and the bone/screw contact of the miniplate system increased with time.

A bioabsorbable poly-L-lactide (PLLA) miniplate and screw system for osteosynthesis in oral and maxillofacial surgery

A bioabsorbable poly-L-lactide (PLLA) miniplate and screw system for osteosynthesis in oral and maxillofacial surgery

An evaluation of the Wu¨rzburg titanium miniplate osteosynthesis system for mandibular fixation

We present an 8-year experience with the Wu¨rzburg noncompression titanium miniplate system for the rigid fixation of the mandible during elective head and neck cancer surgery in a consecutive series of 100 patients. One half of the miniplates were used to fix mandibulotomies undertaken for surgical access. The remaining half were in patients undergoing reconstruction of segmental mandibular defects, the vast majority (92%) with vascularised bone grafts. One to four variously shaped miniplates were used per patient (mean = 1.5), plate size ranging from 4 to 40 holes. Fifteen patients (15%) developed complications which included 3 mandibular osteoradionecrosis, 8 broken, 5 infected, and 4 exposed plates. Three of the eight fractured plates were associated with nonunion. In this study, the main advantages of titanium miniplate fixation, namely ease of application, decreased fixation time and malleability, were accompanied by a level of morbidity which, while comparing well with alternatives, may necessitate a reappraisal of this technique of fixation.

Experimental analysis of functional stability of sagittal split ramus osteotomies secured by miniplates and position screws

Purpose: This study determined the relative functional stabilities of various miniplate systems and configurations used to stabilize sagittal split ramus osteotomies (SSROs) and compared them with conventional internal screw fixation. Materials and Methods: The biomechanical model was a reproducible prototype of a mandible sagittal osteotomy with consistent material and geometric properties. After advancing the distal segment by 7 mm, each set of mandible analogs (1 set = 3 analogs) was fixed bilaterally by one of three miniplate systems applied in various configurations, and tested with and without a supplemental 2.4-mm bicortical screw applied in the retromolar region. Reduced analogs were placed in a straining frame, and simulated masticatory loads were applied alternatively to the mandibular first molars. Ensuing osteotomy site displacements were measured by transducers attached to a computerbased data acquisition program. A coordinate transformation procedure was used to convert the component displacements captured by the individual transducers into a common “instability factor” to reflect fixation stability for each construct and loading condition. Instability factors for the individual constructs were compared with each other and with those obtained from analogs reduced exclusively with 2.4-mm position screws. Results: Osteotomies stabilized with a combination of miniplates and position screws were more stable than those stabilized exclusively with miniplates ( P < .0001). Post-hoc comparisons of mean instability factors (Dunnet's method) showed the miniplate-position screw combinations to be more stable than the 2.4-mm position screw system used as standard ( P < .05). Miniplate systems alone were the least stable of the test constructs, with differential rates of failure between the individual miniplate systems. Conclusions: Exclusive use of miniplate fixation may not provide the consistent stability necessary for early functional restoration after SSROs. The addition of a position screw in the retromolar region substantially enhances the fixation stability of miniplate systems. The use of miniplates with retromolar position screws offers both technical and stability advantages over conventional miniplate or internal screw fixation. The fixation stability of the miniplate-position screw combination is independent of the type of miniplate system used.

Complications of miniplate osteosynthesis in the treatment of mandibular fractures

Miniplate osteosynthesis with 2.0-mm screws is being increasingly utilized in the treatment of mandibular fractures, midface fractures, zygomatic fractures, orthognathic surgery, and in craniomaxillofacial surgery. It enables better anatomic reduction, better stability of fracture lines, quick recovery and return of function. To examine complications related to its use, data were compiled from the preoperative, immediately postoperative, and 6-months' postsurgery examinations of 143 patients with isolated mandibular fractures. Sixteen of the patients (11.2%) presented with postoperative complications that were related to the miniplate system. The authors' experience and data support the theory that the complication rate is related more to the surgical approach and technique than to the time elapsed between injury and operation.

Miniplate osteosynthesis of low subcondylar fractures of the mandible by intraoral approach: Indications, method, results

We present an 8-year experience with the Wu¨rzburg noncompression titanium miniplate system for the rigid fixation of the mandible during elective head and neck cancer surgery in a consecutive series of 100 patients. One half of the miniplates were used to fix mandibulotomies undertaken for surgical access. The remaining half were in patients undergoing reconstruction of segmental mandibular defects, the vast majority (92%) with vascularised bone grafts.One to four variously shaped miniplates were used per patient (mean = 1.5), plate size ranging from 4 to 40 holes. Fifteen patients (15%) developed complications which included 3 mandibular osteoradionecrosis, 8 broken, 5 infected, and 4 exposed plates. Three of the eight fractured plates were associated with nonunion.In this study, the main advantages of titanium miniplate fixation, namely ease of application, decreased fixation time and malleability, were accompanied by a level of morbidity which, while comparing well with alternatives, may necessitate a reappraisal of this technique of fixation.