Comparative evaluation of 2.0-mm locking plate system vs 2.0-mm nonlocking plate system for mandibular fracture: a prospective randomized study

This study evaluated the efficacy of a 2.0-mm locking plate/screw system compared with a 2.0-mm non-locking plate/screw system in mandibular fractures. A prospective randomized clinical trial was conducted. Patients were randomly assigned to receive 2.0-mm locking plates (group A) or 2.0-mm nonlocking plates (group B). All patients were followed up for 12 weeks postoperatively. Complications were analysed according to the type of plate used and the site of fracture. Fifty patients with 76 fractures met the inclusion criteria. Thirty-six fracture sites were treated with 2.0-mm locking plates and 40 with 2.0-mm nonlocking plates. The number of patients requiring postoperative maxillomandibular fixation was significantly higher in group B (p < 0.01); seven complications occurred representing 9% of the total. Two complications occurred in the locking group and five in the nonlocking group with complication rates equalling 6% and 13%, respectively. When comparing the overall complication rates according to plates used, the χ² test showed no statistically significant difference between the locking and nonlocking plates (p > 0.05). In conclusion, mandible fractures treated with 2.0-mm locking plates and 2.0-mm nonlocking plates present similar short-term complication rates.     

自锁板(钉)系统在下颌骨手术中的应用

不同类型的接骨板为下颌骨骨折和截骨提供了稳定的固定。传统接骨板（钉）系统的缺点是接骨板必须与骨面完全贴合才能防止在螺钉拧紧时，骨段凶适应接骨板形态而发生位置改变和咬合关系变化。自锁板（钉）系统在下颌骨骨折和骨缺损的治疗中所显现的优势远远超过其他板（钉）系统。通过将螺钉锁结徉板上而获得稳定性，自锁板（钉）系统的独特优势就足接骨板不必与骨而紧衔接触.     

A comparison between 2.0-mm standard and 2.0-mm locking miniplates in the management of mandibular fractures

Purpose  The purpose of this clinical study was to compare effectiveness of 2.0-mm locking miniplates and screws with 2.0-mm standard miniplates and screws in treating mandible fractures. Patients and methods  A randomized prospective study comprising of 40 samples, where 20 patients (group 1) were treated with locking plates and 20 patients (group 2) were treated with standard miniplates. All the cases were evaluated for the type of fracture, need for the Intermaxillary Fixation (IMF) and its duration, duration of surgery, anatomic reduction, paresthesia / neurosensory changes, occlusal discrepancies, infection at the fracture site and any need for the removal of the plates and screws. Results  In our study Road Traffic Accidents (RTA) accounted for the majority of patients 30 (70%). RTA was more prevalent (52.5%) in 21–30 age group, with assault being more common (67%) in 25–35 years. There was a significant difference between group 1 and 2 in postoperative occlusal discrepancy and need for IMF (p=0.008). There was no significant difference in complication rates between group 1 and group 2 patients. Conclusion  Locking plate/screw system proved to be more rigid than conventional plate/ screw system, thereby reducing the need and duration of IMF. However there was no significant difference in complication rates.     

Comparison of a 2.0-mm locking system with conventional 2.0- and 2.4-mm systems in the treatment of mandibular fractures: a randomized controlled trial

Purpose

A comparative study of the use of the 2.0-mm locking fixation system with conventional systems in the treatment of mandibular fractures was performed.

Methods

For this study, 87 consecutive patients with 112 mandibular fractures were randomized to receive either 2.0-mm locking plates (n = 45) or conventional 2.0- or 2.4-mm plates (n = 42) and had a minimum follow-up of 6 months. Fractures were classified based on the degree of displacement and complexity. Statistical analyses were used to verify possible differences between the groups when separately compared unfavourable and favourable cases (p ≤ 0.050).

Results

Despite randomization, systemic diseases were more frequent in the 2.0-mm locking group in favourable cases. Substance abuse occurred predominantly in the 2.0-mm locking group, in unfavourable and favourable fractures. There were more cases of complex fractures in the conventional group in unfavourable cases. One case involving a major postoperative complication occurred in the locking group (2.2%) and three cases occurred in the conventional group (7.1%) but with no significant difference between groups. In this study, there were no major differences between conventional and locking 2.0-mm locking systems with regard to the outcome of treated mandibular fractures, showing that both are adequate as long as the criteria of their indication and requirements for installation are met.

Conclusions

It was concluded that the 2.0-mm locking fixation system can replace conventional systems in the treatment of mandibular fractures; in addition, this approach was effective in the treatment of unfavourable fractures that typically require the 2.4-mm conventional system.

     

Fixation of mandibular angle fractures with a 2.0-mm 3-dimensional curved angle strut plate.

PURPOSE: The aim of this study was to evaluate our experience and complication rate with the use of a 3-dimensional 2.0-mm curved angle strut plate for mandibular angle fracture fixation. PATIENTS AND METHODS: This was a retrospective evaluation of 37 patients with noncomminuted mandibular angle fractures fixated with a transorally placed curved 2.0-mm strut plate. Postoperative intermaxillary fixation was used in 5 patients for a mean period of 22 days. A nonchewing diet was prescribed for 6 weeks. Records were reviewed for demographic information, medical history, fracture characteristics, operative management, and complications. RESULTS: Two patients developed infections requiring plate removal and reapplication of fixation. Both of these patients had a molar in the fracture line that was left in place during the first operation. One patient developed a mucosal wound dehiscence without consequence. After a mean follow-up period of 10 weeks, 39.4% of patients with a postinjury/pretreatment inferior alveolar nerve deficit reported a return to normal sensation. All patients who developed a sensory deficit as a result of surgery reported full recovery of sensation. A persistent sensory deficit appeared to be related to fracture displacement. CONCLUSION: Fixation of noncomminuted mandibular angle fractures with a 2.0-mm curved angle strut plate was predictable. This plate is low in profile, strong yet malleable, facilitating reduction and stabilization at both the superior and inferior borders. Development of a postoperative infection appeared to be related to failure of removal of a molar in the fracture line. The infection rate of 5.4% found in this study compares favorably with that seen with reconstruction plates. Use of this plate did not appear to cause a permanent sensory deficit in this study.     

A prospective randomized clinical trial comparing 2.0-mm locking plates to 2.0-mm standard plates in treatment of mandible fractures.

PURPOSE: The purpose of this study was to compare standard 2.0-mm monocortical plates to 2.0-mm locking plates in the treatment of mandible fractures. PATIENTS AND METHODS: A prospective randomized clinical trial was conducted at Harborview Medical Center in Seattle, WA, from January 1, 2002, to February 1, 2003, to compare 2.0-mm locking plates to 2.0-mm standard plates in treating consecutive mandible fractures. Patients were randomly assigned to receive locking 2.0-mm plates (group A) or nonlocking 2.0-mm plates (group B). Complications were divided into major and minor categories. Each complication was analyzed according to which plate was used and where the fracture occurred. The number of days from injury to operation, average age, gender, American Society of Anesthesiologists (ASA) classification,compliance, and social habits were all reviewed. RESULTS: Ninety patients with 122 fractures met the inclusion criteria. Sixty-four fracture sites were treated with locking plates and 58 with standard plates. A total of 6 complications occurred: 2 occurred at the angle, 3 at the parasymphysis, and 1 at the body. Three complications occurred in the locking group and 3 in the standard group with complication rates equaling 4.6% and 5.2%, respectively. When comparing the overall complication rates according to plates used, the Fisher exact test showed no statistically significant difference between the locking and standard plates (P = .90). The 95% confidence interval for the odds ratio is from 0.1 to 7. CONCLUSION: Mandible fractures treated with 2.0-mm locking plates and standard 2.0-mm plates present similar short-term complication rates.     

In vitro mechanical assessment of 2.0-mm system three-dimensional miniplates in anterior mandibular fractures

This study constituted a comparative assessment of the mechanical resistance of square and rectangular 2.0-mm system three-dimensional miniplates as compared to the standard configuration using two straight miniplates. 90 polyurethane replica mandibles were used for the mechanical trials. Groups 1, 2, and 3 simulated complete symphyseal fractures characterized by linear separation of the central incisors; groups 4, 5, and 6 simulated parasymphyseal fractures with an oblique configuration. Groups 1 and 4 represented the standard method with two straight miniplates set parallel to one another. Square miniplates were used in groups 2 and 5, and rectangular miniplates in groups 3 and 6. A universal testing machine set to a velocity of 10 mm/min and delivering a vertical linear load to the first left molar was used to test each group. Maximum load values and load values with pre-established dislocation of 5 mm were obtained and submitted to statistical analysis using a calculated reliability interval of 95%. The mechanical performances of the devices were similar, except in the case of rectangular plates used in the parasymphyseal fractures. The innovative fixation methods used showed significantly better results in the case of symphyseal fractures.     

Evaluation of fracture healing and subimplant bone response following fixation with a locking miniplate and screw system for mandibular angle fractures in a sheep model

This study aims to establish a mandible fracture model, and to review fracture healing following fixation with a locking miniplate system. Eighteen 2-year-old sheep were divided into three groups of six. Each animal had a single fracture that was anatomically reduced and internally fixed by a single 4-hole plate with two monocortical screws each side of the fracture. The fractures were internally fixed with poorly contoured conventional miniplates or poorly contoured mini-locking plate or well contoured conventional miniplates. Two sheep in each of the three groups were killed at 2, 4 and 8 weeks after surgery. The mandibles were radiographed then decalcified specimens were reviewed microscopically. No clinical difference was observed between the groups. All fractures were at an advanced stage of bony union by 4 weeks. Fracture union appeared radiographically more advanced with the locking plate system. This study established a protocol for simulating a fracture model for the study of fracture healing. A more advanced stage of union was seen for fractures internally fixed with locking plates/screws than with a conventional system. The observations suggest the purported biological benefits of locking miniplate system do exist.     

Failure strength of 2.0 locking versus 2.0 conventional Synthes mandibular plates: A laboratory model.

PURPOSE: This laboratory study compared the performance of locking versus nonlocking Synthes (Synthes, Paoli, PA) 2-mm mandibular fixation plates. The purpose of the study was to determine if there are physical or mechanical properties to support the use of one rigid fixation device over the other. MATERIALS AND METHODS: A bovine rib model was selected for this study because they closely approximate characteristics of the human mandible. Two experimental groups composed of 10 locking and 10 nonlocking 2-mm plates were secured to randomly selected osteotomized bovine ribs using 10-mm monocortical screws. The specimens were loaded using a 4-point bending system to the point of failure using a MTS model 309.00 servo-hydraulic testing system (MTS Systems Corp, Eden Prairie, MN) with a custom fabricated fixator. The data was obtained with TestStar 2 version 4.0 and TestWare Sx 4.0 software (MTS Systems Corp), and analyzed to determine if there was any difference in performance between the 2 mandibular plate designs. RESULTS: Overall, there were no statistically significant differences between the locking and conventional 2-mm mandibular plate. Of the 20 samples tested, 1 (nonlocking) had a unique early screw failure (pullout) inconsistent with any other samples and was not analyzed. Of the remaining 19 samples, 17 produced a yield failure, bend, or stretch rather than a plate fracture. Both of the plate fractures occurred in the nonlocking plates. Although the data suggested that this mode of failure was more common in nonlocking plates, the difference between both groups in the mode of failure did not achieve statistical significance (chi2 = 2.0, P = .16). Thus, yield was the predominant mode of failure for both types of devices. The force at which each device failed was also similar in both groups. The force of failure for the nonlocking plates was 559.9 N (SD = 247.9), whereas the locking plate failure strength was 637.8 N (SD = 276.3; t (17) = 0.6, P = .53). The results indicated that there was no suggestion that one plate might be stronger than the other. CONCLUSIONS: In this laboratory model, no significant differences were found between the 2 types of mandibular plates. Although studies have shown the locking system to be more rigid, this study suggested that the type and degree of failure are more likely related to bone quality and surgical technique when using the 2-mm mandibular plate. Additional prospective studies are needed to correlate these results in patient models.     

Fixation of mandibular fractures with 2.0-mm miniplates: review of 191 cases.

PURPOSE: Our goal was to study the use of 2.0-mm miniplates for the fixation of mandibular fractures. Patients and Methods: Records of 191 patients who experienced a total of 280 mandibular fractures that were treated with 2.0-mm miniplates were reviewed. One hundred twelve of those patients, presenting 160 fractures, who attended a late follow-up were also clinically evaluated. Miniplates were used in the same positions described by AO/ASIF. No intermaxillary fixation was used. All patients included had a minimum follow-up of 6 months. Demographic data, procedures, postoperative results, and complications were analyzed. RESULTS: Mandibular fractures occurred mainly in males (mean age, 30.3 years). Mean follow-up was 21.92 months. The main etiology was motor vehicle accident. The most common fracture was the angle fracture (28.21%). Twenty-two fractures developed infection, for an overall incidence of 7.85%. When only angle fractures are considered, that incidence is increased to 18.98%. Although only 1 patient (0.89%) described inferior alveolar nerve paresthesia, objective testing revealed sensitivity alterations in 31.52% of the patients who had fractures in regions related to the inferior alveolar nerve. Temporary mild deficit of the marginal mandibular branch was observed in 2.56% of the extraoral approaches performed and 2.48% presented with hypertrophic scars. Incidence of occlusal alterations was 4.0%. Facial asymmetry was observed in 2.67% of the patients, whereas malunion incidence was 1.78%. Fibrous union, mostly partial, occurred in 2.38% of the fractures, but only 1 of those presented with mobility (0.59%). Condylar resorption developed in 6.25% of the fixated condylar fractures. Mean mouth opening was 42.08 mm. CONCLUSION: The overall incidence of complications, including infections, was similar to those described for more rigid methods of fixation.     

Transoral 2.0-mm miniplate fixation of mandibular fractures plus 2 weeks' maxillomandibular fixation: a prospective study.

PURPOSE: We conducted a study to assess the efficacy of intraoral treatment of mandibular fractures using a 2.0-mm miniplate and 2 weeks of maxillomandibular fixation (MMF). PATIENTS AND METHODS: Forty-four mandible fractures in 31 patients with a mean of 15 days of MMF were included in this study. A 2.0-mm miniplate was adapted along Champy's lines of ideal osteosynthesis and secured with four 8.0-mm monocortical screws. All patients were followed for at least 8 weeks after surgery. The incidences of bone or soft tissue infections, wound dehiscence, nonunion, malunion, malocclusion, plate fractures, and iatrogenic neurosensory deficits were prospectively evaluated. RESULTS: Primary bone healing was achieved in 100% of cases. No soft or hard tissue infection, malocclusion, malunion, nonunion, dental injuries, plate fracture, or iatrogenic nerve injuries were observed. Two (4.52%) minor complications-intraoral wound dehiscences-were noted. CONCLUSIONS: The use of a single 2.0-mm miniplate adapted along Champy's line of ideal osteosynthesis and stabilized with 4 monocortical screws plus 2 weeks of MMF was a viable treatment modality for mandibular fractures.     

下颌骨加压螺钉钉道预备器的研制与应用

目的:研制一种在以加压螺钉固定下颌骨骨折时,在下颌骨上准确,快速地预备出加压螺钉钉道的手术器械,方法:该器械的由主托架,骨固定夹,万向关节及麻花钻导和管组成,骨固定夹夹持固定骨折断端,万向关节用以选择预定钉道及角度,结果:该器械在固定骨折断端的同时,用麻花钻连续制备出骨糈端外侧及内侧的钉道,保证了断端内外侧钉道的同轴性,2年来该器械成功地应用于6例下颌骨骨折治疗,显示了该器械的优越性能.结论:研制出的下颌骨用加压螺钉钉道预备器简化了手术操作,准确,快速地预备出加压螺钉钉道.     

The use of an intermaxillary fixation screw for mandibular setback surgery.

PURPOSE: To assess skeletal stability after mandibular setback surgery with and without an intermaxillary fixation (IMF) screw. PATIENTS AND METHODS: The subjects were 40 patients with mandibular prognathism. The subjects underwent sagittal split ramus osteotomy with titanium plate fixation and were divided into 2 groups, 1 with and 1 without an IMF screw. A lateral cephalogram was done preoperatively, immediately after surgery, and 1 month, 3 months, and 6 months postoperatively. The 2 groups were then compared statistically. RESULTS: In the comparison of the time-course change between the 2 groups with repeated measure analysis of variance, there were significant differences in occlusal plane (between subjects, F = 2.517; df = 4; P = .0437) and convexity (between subjects, F = 4.048; df = 4; P = .0038). However, there was no significant difference in the other measurements. CONCLUSION: This study suggested that in most measurements, there was no significant difference between 2 groups with and without an IMF screw in time-course skeletal change. However, use of IMF screws was helpful for orthognathic surgery as a rigid anchor of IMF.     

New resorbable plate and screw system in pediatric craniofacial surgery

Early forms of resorbable fixation induced foreign body reactions requiring surgical removal of the fixation material. Most current plating systems attempt to circumvent this phenomenon by altering the composition of the α esters involved. ResorbX (KLS Martin, Jacksonville, FL), a plating system derived from 50:50 poly(D,L)lactide, boasts short resorption times, minimal foreign body reaction, and adequate strength for bony fixation. We present our experience with 134 patients undergoing correction of primary craniosynostosis, using ResorbX. One hundred thirty-four consecutive craniosynostosis patients underwent correction with calvarial remodeling by the senior author between April 2002 and March 2008. Five patients had 2-stage repairs. Postoperative analysis included plate visibility or palpability, head contour, and the incidence of complications. The mean age at repair was 17.0 months, with the median age being 9.0 months (range, 2.5-137 months). Postoperative follow-up visits were recorded at 3-month intervals from 0 to 24 months. Synostosis diagnoses were as follows: 43 metopic, 37 sagittal, 27 coronal, 5 lambdoid, and 27 multisutural synostosis. There were 3 complications requiring operative intervention. Three plates became exposed through the coronal excision, requiring removal, for an overall complication rate of 2%. Forty-four patients (31.7%) had a visible mass at the site of fixation at some point postoperatively; all of these resolved through observation only. Overall postoperative head aesthetics were deemed satisfactory to excellent, and no instances of contour regression occurred. This study documents the safety and efficacy of ResorbX in pediatric cranial vault remodeling. The system is easy to use, and with the advent of an ultrasonic pin, more abbreviated operating and anesthesia times are achievable.     

Titanium-coated hollow screw and reconstruction plate system (THORP) in mandibular reconstruction

Clinical results are presented which have been obtained from mandibular reconstruction with the Titanium-coated Hollow Screw and Reconstruction-Plate system (THORP) in 7 selected patients. In 3 of the patients primary bone grafting was performed with simultaneous implantation of titanium fixtures for dental reconstruction. The reconstruction-plates have shown excellent functional stability with no failures, such as loosening of screws, within an observation period up to 2 1/2 years. The system was submitted to immediate full functional loading despite the limited number of 2-3 fixation screws for each end of the plate. Among several technical advantages of the system are the possibility of lingual plate application and reconstruction with a three-dimensionally free, adjustable condylar prosthesis.     

Complications of locking and non-locking plate systems in mandibular fractures

This systematic review and meta-analysis was performed to critically assess the methodological quality of the existing systematic reviews, and to evaluate the postoperative complications of the mandibular fractures treated with locking and non-locking plate systems. An electronic search was conducted in PubMed, Embase, Web of Science, Cochrane library’s electronic databases and grey literate using a combination of Medical Subject Heading terms and key words, until September 2018. No restrictions were applied to the search strategy. In total, three relevant systematic reviews were included, and the quality of these studies was low. A total of 33 studies (20 randomized studies and 13 non-randomized studies) were included in this systematic review, and 16 of them were included in meta-analysis. Most of the included randomized studies had an unclear risk of bias (Cochrane Collaboration); the quality of non-randomized studies ranged between 6 and 17 (Methodological Index for Non-Randomized Studies ? MINORS). Based on the results of our meta-analysis, we conclude that locking plates are superior only with respect to the need for mandibulomaxillary fixation (MMF) in the early postoperative period.