Use of a locking reconstruction bone plate/screw system for mandibular surgery

Prevalence of surgical site infections after open reduction and internal fixation for mandibular fractures: a systematic review and meta-analysis

Our study aims to estimate the prevalence of surgical site infections (SSI) following open reduction and internal fixation (ORIF) for mandibular fractures and to determine the effect of potential moderators on it. A systematic literature search (Medline and Scopus databases) was conducted independently by two reviewers. The pooled prevalence with 95% confidence intervals was estimated. Quality assessment as well as outlier and influential analysis were performed. Additionally, subgroup and meta-regression analysis were conducted in order the effect of categorical and continuous variables on the estimated prevalence to be investigated. In total, seventy-five eligible studies (comprising a sum of 5825 participants) were included in this meta-analysis. The overall prevalence of SSI following ORIF for mandibular fractures was estimated as high as 4.2% (95% CI 3.0-5.6%) with significant heterogeneity between studies. One study was identified to be critically influential. In the subgroup analysis, the prevalence was 4.2% (95% CI 2.2-6.6%) among studies conducted in Europe, 4.3% (95% CI 3.1-5.6%) among studies conducted in Asia and higher among those conducted in America (7.3%) (95% CI 4.7-10.3%). It is important for healthcare professionals to be aware of the etiology of these infections, despite the relatively low rate of SSI in these procedures. However, further, well-designed prospective and retrospective studies need to be conducted in order this issue to be fully clarified.

Efficacy of Three-dimensional Locking Miniplates versus Three-dimensional Standard Miniplates in the Management of Mandibular Fractures - A Prospective Clinical Study

Introduction

Fifty patients were included to compare the efficacy of three-dimensional (3D) locking miniplates versus 3D standard miniplates in the management of mandibular fractures.

Materials and Methods

Fifty patients were randomly allocated to either 3D locking miniplate group or 3D standard miniplate group. All patients were followed for six months to compare post-operative occlusion, stability and associated clinical complications such as wound dehiscence, infection and plate/screw fracture and mental nerve paraesthesia.

Results

All the fractures were adequately fixed when checked intraoperatively. Four patients in each group had mildly deranged occlusion, one patient in Group A and two patients in Group B had reduced stability. None of the patients had complications of non-union or malunion. In Group A, one out of 25 patients had mental nerve paraesthesia and two had wound dehiscence. Moreover, in Group B, two patients had mental nerve paraesthesia and two others had wound dehiscence. The data when compared were statistically significant (=0.05).

Discussion

The overall result of our study led us to the conclusion that both the plating systems were satisfactory and there is no statistically significant difference when used for open reduction and fixation in mandibular fractures. Healing was satisfactory in both groups.

Mini-plate versus reconstruction bar fixation for oncologic mandibular reconstruction with free fibula flaps: A systematic review and meta-analysis

Introduction There is currently no consensus as to the comparative complication profiles of mini-plate (MP) and reconstruction bar (RB) osseous fixation in fibula flap mandibular reconstruction. The aim of this study is to compare complication rates associated with the use of MP versus RB fixation for vascularized fibula free flap (FFF) reconstruction of oncologic mandibular defects in an effort to better guide hardware utilization and pre-operative virtual surgical planning methods. Methods A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, EMBASE, and Cochrane Library databases were queried to identify studies related to FFF-based mandibular reconstruction with either MP or RB fixation. Primary endpoints of interest were plate complications, wound infection, mal- or non-union, and total flap loss. Complication rates were calculated as weighted proportions and compared via Fisher's exact testing. Results Sixteen studies met inclusion criteria, which examined 1,513 patients. Only three studies directly compared MP fixation with RB fixation. MP fixation was used in 828 (54.7%) cases and RB fixation in 685 (45.3%) cases. MP fixation demonstrated greater rates of plate-related complications (32.5% versus 18.8%, p < 0.01, respectively), fistula formation (15.8% versus 4.7%, p = 0.04), total flap loss (9.4% versus 4.7%, p = 0.02), partial flap loss (20.6% versus 6.1%, p < 0.01), and re-operation for vascular compromise (13.3% versus 4.0%, p < 0.01). Rates of infection, mal-union/non-union, and wound dehiscence were similar across both groups. Conclusion Our results suggest that MP use may be associated with higher rates of plate-related complications. Though limited by outcome reporting heterogeneity, this review can serve as a template for future investigations evaluating the safety profiles of MP and RB fixation in head and neck surgery.

Comparison of locking and non-locking reconstruction plate-screw system in lateral mandibular defects by finite element analysis

PURPOSE

The purpose of this study is to analyze and compare stress distribution on bone screws and plate systems in locking and non-locking screw-plates design in lateral mandibular defects.

MATERIAL AND METHODS

Solid mathematical model of mandible was created by three-dimensional finite elements analysis and 25 mm length of lateral resection (L defect) was performed on the model. Models were reconstructed with 2.4 locking and non-locking reconstruction plate system. Each masticator muscles attached to mandible were simulated as direction, attachment area and magnitude on 3D model to compare with reality. The stress formation on bone and hardware system were evaluated.

RESULT

The stress values on the cortical bone, plate and screw system were higher in conventional plate model than the locking system model. The highest stress values were measured in the proximal segment especially in conjunction with conventional screw system. Furthermore, the distribution of stress on the bone surface was more homogenous in the locking system.

CONCLUSION

It is evident that the use of the locking system in 25 mm length lateral mandibular defects provides an additional advantage over conventional systems in reconstruction models.

Comparative Evaluation of 3d Locking Versus Non-Locking Titanium Miniplates in the Treatment of Mandibular Fracture

The introduction of 3-dimension systems for the treatment of mandibular fractures and continuity has offered certain advantages over other plating system. The present study was undertaken to compare 2.0 mm 3D titanium locking and non-locking miniplates in the management of mandibular fractures. A prospective study was conducted on 40 patients (20 in each group) of mandibular fractures treated by open reduction and internal fixation. Group A patients underwent osteosynthesis using 2.0 mm 3-D titanium locking miniplates while Group B used non-locking miniplates. Subsequent follow-up was assessed for pain, swelling, infection, paresthesia, malocclusion, mobility between fracture fragments and hardware failure in these patients. Functional occlusion was achieved postoperatively in all the patients. At 12 weeks of the time intervals, significant pain was observed in group B. At 1 week interval, 6 (30%) patients in both groups reported with swelling. Only one (10%) patient in each group had paresthesia which got resolved gradually over a period of 3 months. Infection was observed in only 2 (10%) patient in Group B at 3 months. Only 2 (10%) patient in Group B had hardware failure at 3 months interval. Statistically, there was no significant difference between both the groups at any time interval (p > 0.05). 3D titanium locking miniplates are effective in the treatment of mandibular fractures with lesser overall complications as compared to non-locking miniplates.

Remote-controlled internal lengthening plate for distraction osteogenesis in pediatric patients

OBJECTIVES

Limb lengthening by distraction osteogenesis is a technique widely used to treat limb length discrepancy resulting from trauma, congenital limb defects and long bone non-union. For decades, patients have resorted to the Ilizarov apparatus, prone to pin tract infections and scarring. Although implantable lengthening nails have reduced the incidence of complications, they are not applicable in pediatric patients with open growth plates. The aim of this project is to design a remote-controlled internal lengthening device suitable for implantation in children.

METHODS

The proposed device has the form of an internal remote-controlled telescopic lengthening plate, screwed to the lateral side of the bone with locking screws. This is appropriate for use with pediatric patients. It has been tested on an experimental bench which has the form of a vertically sliding platform, on which were stacked weights simulating soft-tissue resistance forces.

RESULTS

This internal lengthening plate generated distraction forces of up to 735 N on wooden and synthetic bones (Sawbones^TM). Furthermore, it maintained a constant distraction speed over the course of the procedure for a given weight.

CONCLUSIONS

This device represents a major advancement in the field of pediatric limb-lengthening, addressing a demographic gap left open by current implantable devices.

Locking Miniplate Osteosynthesis of Anterior Mandibular Fractures-Quo Vadis?

PURPOSE

This study compared the clinical stability and efficacy of locking miniplates with those of standard miniplates in the osteosynthesis of anterior mandibular fractures using bite force recordings and other clinical parameters.

MATERIALS AND METHODS

A prospective randomized double-blinded clinical trial was carried out in patients from various hospitals of Hassan (India). Patients were randomly divided into 2 groups of locking (test) and standard (control) miniplate osteosynthesis. Bite force measurements were performed preoperatively and postoperatively at weekly intervals for 6 weeks using a bite force recorder. As a secondary outcome, patients also were assessed for other clinical parameters that might interfere with successful osteosynthesis at the fracture site. Appropriate statistical testing for intra- and intergroup measurements was carried out.

RESULTS

Forty-eight men 28 ± 12.3 years old met the inclusion criteria (24 patients in each group). A statistically significant difference (P < .05) was found in the incisor bite force between the 2 groups, with values in the locking group exceeding those in the standard group at postoperative weeks 2 and 5. Duration of surgery was shorter in the locking group (P = .015). No relevant difference was found for the other clinical parameters.

CONCLUSIONS

Bite force statistically increased at progressive follow-up visits compared with the preoperative recording in the locking group. Bite force recordings of patients treated with locking plates were higher and statistically relevant compared with those of patients treated with standard miniplates at the incisor region at postoperative weeks 2 and 5. The clinical outcomes of the 2 miniplate systems in the present study were similar; however, the locking miniplates required a relatively shorter operating time, produced less trauma to the periosteum and soft tissues with less hardware, and can be used as a "1-plate-for-all" system.

Comparative evaluation of a single 2.0-mm AO locking reconstruction plate with conventional miniplate osteosynthesis for treatment of linear non-comminuted fractures of symphysis and parasymphsis region of the mandible

The objective of the study was to evaluate and compare the relative efficacy of treating linear non-comminuted mandibular fracture of symphysis and parasymphysis region using single 2.0-mm AO locking reconstruction plate or using two conventional miniplates. In this study, 80 patients of symphysis or parasymphysis fracture were divided randomly in two equal groups and treated with open reduction and internal fixation using two 2.5-mm miniplates or with a single 2.0-mm AO locking reconstruction plate. Operating time in case of open reduction and fixation using a single 2.0-mm locking reconstruction plate was significantly less when compared to open reduction and fixation using two conventional miniplates. Both groups showed satisfactory fracture reduction and healing. No postoperative malocclusion was noted, and both groups showed comparable improvement in masticatory efficiency. In conclusion, fracture fixation using a single 2.0-mm AO locking reconstruction plate without use of a second plate at the superior border for treatment of linear non comminuted mandibular fracture in symphysis and parasymphysis region gives comparable results as with treatment by conventional miniplate system and provides significant savings in operating time, ease of use and decrease in amount of hardware incorporated in the body.

Management of Mandibular Fractures Using Locking and Nonlocking Miniplates

PURPOSE

The study proposed to determine the superiority between locking plate and nonlocking miniplate for mandibular fractures (MFs) treatment.

METHODS

A comprehensive electronic search examining Medline-Ovid, Embase, and PubMed databases language without date was performed in February 2018. Inclusion criteria were studies in humans, including randomized controlled trials, controlled clinical trials, with the aim of comparing the 2 techniques. The quality of studies was assessed, and the relative risk (RR) with its corresponding 95% confidence interval (CI) was assessed to measure the effect size.

RESULTS

Thirteen publications were enrolled into the analysis. The results showed that there were significant differences in overall complications (RR, 0.62; 95% CI, 0.351-1.094; P = 0.06), postoperative infection (RR, 0.503, 95% CI, 0.223-1.136) when comparing locking miniplates with nonlocking miniplates in treating mandible fractures. The incidence of malocclusion showed a statistically significant difference in the outcome favoring locking miniplates (fixed: RR, 0.503; 95% CI, 0.125-2.030; P = 0.06). In addition, the use of locking miniplates had a lower postoperative maxillomandibular fixation rate than the use of nonlocking miniplates (RR, 0.414; 95% CI, 0.196-0.872; P = 0.002).

CONCLUSION

The result of meta-analysis revealed that use of locking plate is superior to the nonlocking plate in the reducing of postoperative complication rates in the management of MFs.

Clinical Study of Reconstruction Plates Used in the Surgery for Mandibular Discontinuity Defect

BACKGROUND/AIM

Postresective mandibular reconstruction is common in cases of oral and mandibular tumors. However, complications such as plate fracture and/or plate exposure can occur. The purpose of this study was to analyze complications and survival of reconstructive plates used to correct mandibular defects caused by oral cancer.

PATIENTS AND METHODS

Clinical and radiological data from 34 patients were analyzed. Only discontinuous mandibular defect cases were included in this study. All cases were classified using the Hashikawa's CAT and Eichner's classification methods. Then, we determined whether these classifications and clinical treatment methods were significantly related to complications.

RESULTS

Complications after mandibular reconstruction occurred in 10 of 34 patients, specifically, two plate fractures, one screw fracture, and seven plate exposures occurred. The plate fractures occurred 5 and 6 months after operation, and the screw fracture occurred 39 months after operation. Using the Hashikawa's CAT classification, the two cases of plate fracture were one of AT type and the other of T type, and the screw fracture was AT type. Using Eichner's classification, all three cases of plate and screw fractures were B2 type.

CONCLUSION

We suggest that plate and screw fractures were caused by the type of mandibular defect and bite force.

Novel Patient-Specific 3-Dimensional Printed Fixation Tray for Mandibular Reconstruction With Fibular Free Flaps

Segmental mandibular defects secondary to infectious, traumatic, and pathologic conditions can be debilitating because of their impact on function and facial esthetics. Several reconstructive techniques are available, with vascularized flaps commonly used for the reconstruction of large bony or composite segmental defects. The free fibular flap for mandibular reconstruction is well documented and remains a commonly used flap because of its bone length, versatility, distant location from the head and neck region that allows for a 2-team approach, and ability to simultaneously place endosseous implants. Virtual surgical planning (VSP) and guided resection and reconstruction of maxillofacial defects have facilitated complex 3-dimensional (3D) reconstruction. The accuracy and fidelity of VSP are dependent on the intraoperative execution of the VSP, with computer-aided design and computer-aided modeling of patient-specific cutting guides and hardware providing a template for its execution. The goal of this report is to describe the authors' experience with the use of a novel 3D printed fixation tray designed from the VSP data. It provides dual functionality by aiding in alignment and stabilization of the fibular segments and concomitantly providing patient-specific anatomic references for indexing of bony and soft tissue components. This tray enables rapid ex vivo configuration of the fibula segment(s) with the reconstruction bar relative to the native mandibular segments and allows the compiled construct to be transferred to the head and neck for insetting as a precisely configured single unit.

A Passive and Wireless Sensor for Bone Plate Strain Monitoring

This paper reports on a sensor for monitoring bone plate strain in real time. The detected bone plate strain could be used for judging the healing state of fractures in patients. The sensor consists of a magnetoelastic material, which can be wirelessly connected and passively embedded. In order to verify the effectiveness of the sensor, a tibia-bone plate-screw (TBS) model was established using the finite element analysis method. A variation of the bone plate strain was obtained via this model. A goat hindquarter tibia was selected as the bone fracture model in the experiment. The tibia was fixed on a high precision load platform and an external force was applied. Bone plate strain variation during the bone fracture healing process was acquired with sensing coils. Simulation results indicated that bone plate strain decreases as the bone gradually heals, which is consistent with the finite element analysis results. This validated the soundness of the sensor reported here. This sensor has wireless connections, no in vivo battery requirement, and long-term embedding. These results can be used not only for clinical practices of bone fracture healing, but also for bone fracture treatment and rehabilitation equipment design.

A Cheap Hand-Made Mandibular External Fixator?

The external mandibular fixator is one of the tools that maxillofacial have to contain complex fractures, in particular in the context of ballistic traumas or comminuted fractures.The authors present a craft external fixator inspired from Joe Hall Morris fixation. This technique, particularly cheap, can be an alternative to a conventional external fixator. The authors report their advices and tricks to guide the implementation of that external fixator and avoid pitfalls. Indications of this surgical device are discussed.

Assessment of Bite Force in Patients Treated with 2.0-mm Traditional Miniplates versus 2.0-mm Locking Plates for Mandibular Fracture

The objective of this study is to analyze the difference in bite forces in patients treated for mandibular fractures with 2.0 mm conventional and locking titanium plating system. A randomized study was performed for the treatment of fractures of mandible. In this study, 20 adult patients with isolated mandibular fracture were included. The patients were randomly allocated into two groups, that is, Group I-2.0 mm nonlocking (traditional) and Group II-2.0 mm locking plates. Bite force was evaluated at 1st, 3rd, and 6th weeks. Comparison of all the assessed parameters between both the groups depicted no significant difference in terms of pain, swelling including the incidence of infection, paresthesia, and hardware failure. Although same was true in case of bite force between both the groups at various time intervals, there was statistically significant increase in the bite force within the group comprising patients in whom locking plates was used between 1st and 3rd weeks follow-up period and highly significant increase in bite force between 1st and 6th weeks of follow-up period. The rapid improvement of bite force values when locking plates were used implies that the locking plate can be used in preference to conventional plates to achieve early mobilization with assured stability in the treatment of mandibular fractures.

Surgical treatment of comminuted mandibular fractures using a low-profile locking mandibular reconstruction plate system

Objective:

The treatment of comminuted mandibular fractures is challenging due to the severity of associated injuries and the need for a careful diagnosis with adequate treatment planning. Recently, open reduction and stable internal fixation (OR-IF) with a load-bearing reconstruction plate have been advocated for reliable clinical outcomes with minimal complications. This clinical prospective study evaluated OR-IF in the surgical management of comminuted mandibular fractures with a new low-profile, thin, mandibular locking reconstruction plate.

Materials and Methods:

We prospectively assessed OR-IF of comminuted mandibular fractures with a low-profile locking mandibular reconstruction plate in 12 patients (nine men, three women; mean age 32.2 [range 16-71] years) between April 2010 and December 2011. The clinical characteristics and associated clinical parameters of patients were evaluated over a minimum follow-up period of 12 months.

Results:

Traffic accidents caused 50% of the fractures, followed by falls (25%). Four patients (33.3%) had associated midfacial maxillofacial fractures, while five patients had other mandibular fractures. Seven patients (58.3%) needed emergency surgery, mostly for airway management. Anatomical reduction of the comminuted segments re-established the mandibular skeleton in stable occlusion with rigid IF via extraoral (33.3%), intraoral (50%), or combined (16.7%) approaches. Immediate functional recovery was achieved. Sound bone healing was confirmed in all patients, with no complications such as malocclusion, surgical site infection, or malunion with a mean follow-up of 16.3 (range 12-24) months.

Conclusions:

OR-IF using a low-profile reconstruction plate system is a reliable treatment for comminuted mandibular fractures, enabling immediate functional recovery with good clinical results.

Comparative evaluation of bite forces in patients after treatment of mandibular fractures with miniplate osteosynthesis and internal locking miniplate osteosynthesis

Aims and Objectives:

The aim of present study was to compare the stability of fractured mandibular fragments under functional load, when fixed with conventional miniplate and internal locking miniplate.

Materials and Methods:

Bite force (in kg) recorded in twenty mandible fractured patients and fifty normal healthy individuals. Bite force was measured at incisor and molar regions. Comparative evaluation of bite force generated was performed between 10 cases treated with conventional miniplates and 10 cases treated with internal locking miniplates. Bite force generated by patients in mandibular fracture between symphysis and the angle of mandible was recorded in incisor and molar regions preoperatively. The fracture fragments were fixed using the above fixation techniques. Then same recording was undertaken on the 7^th, 14^th, 21^st, 28^th, and 90^th days postoperatively.

Results:

Bite force generated by patients treated with locking plates at the 7^th, 14^th, 21^st, 28^th, and 90^th postoperative days was significantly higher as compared to those in patients treated with miniplates.

Conclusion:

It was observed in our study that the locking plate/screw system offers significant advantages over the conventional plating system. There are no intraoperative difficulties associated with placement of the plate.

A meta-analysis comparing the 2.0-mm locking plate system with the 2.0-mm nonlocking plate system in treatment of mandible fractures

PURPOSE

The purpose of this meta-analysis was to evaluate the efficacy of the 2.0-mm locking miniplate/screw system in comparison with the 2.0-mm nonlocking miniplate/screw system in treatment of mandible fractures.

METHODS

Articles published until March 2013 were searched in the PubMed and EMBASE electronic databases. Eligible studies were restricted to comparative controlled trials.

RESULTS

Four studies with 220 patients and 420 fracture sites were enrolled into the analysis. The results showed that there were no significant differences in overall complications (odds ratio [OR], 0.57; 95% confidence interval [CI], 0.24-1.36; P = 0.21), postoperative infection (OR, 0.43; 95% CI, 0.13-1.41, P = 0.17), and postoperative pain (P > 0.05) when comparing 2.0-mm locking miniplates with 2.0-mm nonlocking miniplates in treating mandible fractures. However, the use of 2.0-mm locking miniplates had a lower postoperative maxillomandibular fixation (MMF) rate than the use of 2.0-mm nonlocking miniplates (OR, 0.18; 95% CI, 0.08-0.41; P < 0.0001).

CONCLUSIONS

Mandible fractures treated with 2.0-mm locking miniplates and nonlocking 2.0-mm miniplates present similar short-term complication rates, and the low postoperative maxillomandibular fixation rate of using 2.0-mm locking miniplates also indicates that the 2.0-mm locking miniplate has a promising application in treatment of mandibular fractures.

The Use of 2.4-mm Locking Plate System in Treating Comminuted Mandibular Fracture by Firearm

Maxillofacial trauma caused by firearms has considerably increased, in which the mandibular body is the site of highest incidence of firearm projectiles. In these cases, the use of titanium plates and screws allows the early restoration of form and function of the mandible with stable and predictable results. Recently, conventional plates have been extensively used to treat comminuted mandibular fractures. Nevertheless, the conventional system presents several limitations such as screw compression against the bone interface and the necessity of precise fit of plate to the bone. To overcome such drawbacks, the locking plates have emerged. The present clinical case reported the operative treatment of mandibular fracture caused by firearm projectiles with the use of locking plate. The indications, advantages, and disadvantages of this system are presented.

Efficacy of locking plates/screw system in mandibular fracture surgery

PURPOSE

The purpose of this study was to determine the efficiency of locking plates and screw system in the treatment of mandibular fracture surgery, by comparing them with the conventional system.

PATIENTS AND METHODS

A protocol for selection of patients with mandibular fractures was developed. One hundred patients were treated by locking plates and screw system and another 100 patients were treated with the conventional system. The patients were prospectively evaluated for the duration of surgery, difficulties encountered during surgery, neurologic changes, postsurgical occlusal relationship, adequacy of reduction and postsurgical complications. Data were compared for statistical significance with Chi-square test and Z-test.

RESULTS

There was statistically significant difference in postoperative infection, postoperative occlusal discrepancy, postoperative plate fracture and postoperative screw loosening and mobility of the fractured fragments and also the working time between the two systems.

CONCLUSION

The results of the present study are comparable with other published data and support the notion that the locking miniplate system is a valid alternative to conventional miniplates with several advantages, the only drawback being the additional working time required during adaptation of this hardware.

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.

Comparative evaluation of 2.0-mm locking plate system vs. 2.0-mm nonlocking plate system for mandibular fractures--a retrospective study

INTRODUCTION

The purpose of this retrospective study is to evaluate the efficacy of the 2.0-mm locking miniplate/screw system in comparison to the 2.0-mm nonlocking miniplate/screw system in mirror image mandibular fractures.

MATERIAL AND METHOD

A retrospective clinical trial was reviewed in the Department of Oral and Maxillofacial Surgery, Government Dental College, Pt. B.D. Sharma University of Health Sciences Rohtak for a period of 30 months (June 2007 to December 2009). A total of 30 patient pairs with isolated identical mandibular fracture (single or multiple) having 88 fractures were analyzed.

RESULTS

A total of 11 complications that occurred represented 12.5% of the total. Six complications occurred at angle, three in the body and two at parasymphysis. Four complications occurred in the locking group and seven in the nonlocking group, with complication rates accounting for 9% and 16%, respectively. When comparing the overall complication rates according to plates used, the chi-square test showed no statistically significant difference between the locking and nonlocking plates (p > 0.05).

DISCUSSION

Mandible fractures treated with the 2.0-mm locking plates and the 2.0-mm nonlocking plates present similar short-term complication rates.

Locking plates in osteoporosis: a biomechanical cadaveric study of diaphyseal humerus fractures

OBJECTIVE

To determine whether locking plates offer an advantage in fixation of fractures in osteoporotic humeral bone.

DESIGN

Biomechanical testing of 18 matched pairs of osteoporotic human cadaver humeri plated posteriorly with either all locked or all nonlocked screws. An established protocol was used to test the constructs with torque applied to a peak of ±10 Nm for 1000 cycles at 0.3 Hz or until failure. Eighteen pairs were tested for failure, 11 pairs were tested for cycles survived, and 10 pairs were tested for stiffness.

SETTING

University biomechanical laboratory.

MAIN OUTCOME MEASUREMENTS

Percentage surviving testing, mean cycles survived, and stiffness.

RESULTS

We observed catastrophic failure of the constructs in 47% of the samples. Humeri plated with nonlocking plates failed at a higher rate than those with locking plates (67% nonlocking vs 28% locking, n = 18 pairs, P = 0.008). Locking constructs also outperformed nonlocking constructs in mean cycles survived (707 cycles locking, 345 cycles nonlocking, n = 11 pairs, P < 0.05) and stiffness at 10 cycles (0.853 Nm/degree locking vs 0.416 Nm/degree nonlocking, n = 10 pairs, P < 0.001).

CONCLUSIONS

Locking plates were shown to provide improved mechanical performance over nonlocking plates in torsional cyclic loading in a osteoporotic cadaveric fracture model. Our results confirm general conclusions of previous work that used a synthetic bone model of osteoporosis, but we found a high rate of catastrophic failure, questioning the validity of the previously published synthetic model of osteoporosis (overdrilling of synthetic bone) for this application.

Efficacy of 2-mm locking miniplates in the management of mandibular fractures without maxillomandibular fixation

BACKGROUND

The management of trauma has evolved greatly over the past many years. Various bone plating systems have been developed to provide stable fixation of mandibular fractures. The introduction of the locking plate/screw system has offered certain advantages over the conventional plating systems. This system does not require intimate adaptation of the miniplates to the underlying bone and has greater stability. This study evaluates the efficacy of locking miniplate/screw system in the treatment of mandibular fractures without maxillomandibular fixation.

MATERIALS AND METHODS

This was a prospective study analyzing 20 patients with undisplaced or minimally displaced mandibular fractures, who reported to Department of Oral and Maxillofacial Surgery, Government Dental College and Research Institute, Bangalore. The selected cases were treated by open reduction and internal fixation using the 2.0 mm locking plate/screw system.

RESULTS

Open reduction and internal fixation with the 2.0 mm locking plate/screw system were achieved in all the 20 cases with satisfactory stability of the fracture fragments. The system was found to be reliable and effective intraoperatively. Only two complications were noted in the study.

CONCLUSION

The locking miniplate system was found to be reliable and effective in management of mandibular fractures without postoperative intermaxillary fixation, however further studies with more sample size is required.

In vitro evaluation of conventional and locking miniplate/screw systems for the treatment of mandibular angle fractures

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm × 6 mm monocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (G2) straight miniplate; in groups 3 and 4, three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p<.01). Locking miniplates offered more resistance than conventional miniplates. Long locking miniplates provided greater stability than short ones.

In vitro biomechanical evaluation of the use of conventional and locking miniplate/screw systems for sagittal split ramus osteotomy

PURPOSE

The aim of this in vitro study was to assess the biomechanical stability of 9 different osteosynthesis methods after sagittal split ramus osteotomy by simulating the masticatory forces and using a 3-point biomechanical test method.

MATERIALS AND METHODS

Forty-five polyurethane hemimandibles with bone-like consistency were randomly assigned to 9 groups (n = 5) and subjected to sagittal split ramus osteotomy. After 4-mm advancement of the distal segment, the bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplate/screw systems: group A, one 4-hole conventional straight miniplate; group B, one 4-hole locking straight miniplate; group C, one 4-hole conventional miniplate and one bicortical screw; group D, one 4-hole locking miniplate and 1 bicortical screw; group E, one 6-hole conventional straight miniplate; group F, one 6-hole locking straight miniplate; group G: two 4-hole conventional straight miniplates; group H, two 4-hole locking straight miniplates; and group I, 3 bicortical screws in an inverted-L pattern. All models were mounted on a base especially constructed for this purpose. Using a 3-point biomechanical test model, the hemimandibles were loaded in compressive strength in an Instron machine (Norwood, MA) until a 3-mm displacement occurred between segments vertically or horizontally. Data were analyzed by analysis of variance and Tukey test (alpha = 1%).

RESULTS

The multiparametric comparison of the groups showed a statistically significant difference (P < .01) between groups that used 2 miniplates (groups G and H), 1 miniplate and 1 bicortical screw (groups C and D), and only bicortical screws (group I) compared with groups that used only 1 miniplate with 2 screws per segment (groups A and B) and 3 screws per segment (groups E and F).

CONCLUSION

The placement of 2.0-mm-diameter bicortical screws in the retromolar region, associated or not with conventional and locking miniplates with monocortical screws, promoted a better stabilization of bone segments. Locking miniplates presented a better performance in bone fixation in all groups.

Are locking screws advantageous with plate fixation of humeral shaft fractures? A biomechanical analysis of synthetic and cadaveric bone

OBJECTIVES

To investigate whether locking screws offer any advantage over nonlocking screws for plate fixation of humeral shaft fractures for weight-bearing applications.

DESIGN

: Mechanical evaluation of stiffness in torsion, bending, and axial loading and failure in axial loading in synthetic and cadaveric bone.

SETTING

Biomechanical laboratory in an academic medical center.

METHODS

: We modeled a comminuted midshaft humeral fracture in both synthetic and cadaveric bone. Humeri were plated posteriorly. Two study groups each used identical 10-hole, 3.5-mm locking compression plates that can accept either locking or nonlocking screws. The first group used only nonlocking screws and the second only locking screws. Stiffness testing and failure testing were performed for both the synthetic bones (n = 6) and the cadaveric matched pairs (n = 12). Fatigue testing was set at 90,000 cycles of 440 N of axial loading.

MAIN OUTCOME MEASURES

Torsion, bending, and axial stiffness and axial failure force after cyclic loading.

RESULTS

With synthetic bones, no significant difference was observed in any of the 4 tested stiffness modes between the plates with locking screws and those with nonlocking screws (anteroposterior, P = 0.51; mediolateral, P = 0.50; axial, P = 0.15; torsional, P = 0.08). With initial failure testing of the constructs in axial loading, both plates failed above anticipated physiologic loads of 440 N (mean failure load for both constructs >4200 N), but no advantage to locking screws was shown. The cadaveric portion of the study also showed no biomechanical advantage of locking screws over nonlocking screws for stiffness of the construct in the 4 tested modes (P > 0.40). Fatigue and failure testing showed that both constructs were able to withstand strenuous fatigue and to fail above anticipated loads (mean failure >3400 N). No difference in failure force was shown between the 2 groups (P = 0.67).

CONCLUSIONS

Synthetic and cadaveric bone testing showed that locking screws offer no obvious biomechanical benefit in this application.