Lag-screw fixation of mandibular parasymphyseal and angle fractures

Comparative Evaluation of Conventional Miniplates, Three-Dimensional Miniplates and Lag Screws for Internal Fixation of Parasymphysis Fracture of Mandible-A Double-Blind Randomized Clinical Study

Purpose

The aim of this study is to clinically and radiographically evaluate the stability of parasymphysis fracture managed with lag screws, miniplates and 3D miniplates.

Materials and Method

Ninety- eight patients diagnosed with parasymphysis fracture were treated using lag screws in group 1, two 4-hole miniplates in group 2 and 3D miniplates in group 3. Intraoperative stability and duration of fixation was assessed. Postoperative clinical evaluation was done at 1 week, 1 month, 3rd month, 6th month and 1 year for complications and oral function. Radiological evaluation was done at 3rd and 6th month. Only 92 patients were considered for statistical analysis since 6 patients were lost during follow-up.

Results

Road traffic accident (65.3%) was the primary cause of mandibular fractures. Postoperative pain score showed a statistically significant difference after 1 week and 1 month duration (P value < 0.001). ANOVA test showed VAS was significantly higher at pre-op followed by 1st day and 1 week, but no significant difference after 3 months in all groups. Radiographic analysis did not show significant difference in approximation of fracture segment among 3 groups after 6 months (P-value = 0.117). Chewing efficiency at 6 months and occlusion by surgeon evaluation at 3 months showed a significant difference (P value < 0.001).

Conclusion

Lag screw fixation was technique-sensitive, relatively inexpensive and was less time consuming method when compared to miniplates and 3D plates. Lag screws and 3D plates are superior in reducing the incidence of complications and better in oblique or sagitally displaced mandibular fractures.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12663-021-01647-5.

Cortical lag screw fixation for the management of mandibular injuries

Objectives

Here, we present cases of mandibular fracture that were managed with the cortical lag screw fixation technique (CLSFT) in order to critically evaluate technique indications and limitations of application at various fracture sites.

Materials and Methods

This was a retrospective cohort study. The study sample was composed of patients suffering from mandibular fractures that were treated by the CLSFT. The outcome variables were fracture type, duration of surgery, number of screws, and pattern of application. Other study categories included patient demographics and causes of injury. Chi-square tests were used to assess descriptive and inferential statistical differences, and the P-value was set at 0.05.

Results

Thirty-three patients were included in the study sample, with a mean age of 30.9±11.5 years and a male predominance of 81.8%. The technique was applied more frequently in the anterior mandibular region (51.5%) than in other sites. Double CLSFT screws were required at the symphysis and parasymphysis, while single screws were used for body and angle regions. No intraoperative and postoperative variables were significantly different except for surgical duration, which was significantly different between the sites studied (P=0.035).

Conclusion

We found that CLSFT is a rapid, cost-effective technique for the fixation of mandibular fractures yielding good treatment results and very limited complications. However, this technique is sensitive and requires surgical expertise to be applied to mandibular fractures that have specialized characteristics.

Principle of Lag-Screw Fixation in Mandibular Trauma

Aims and Objectives:

The aim of the study is to assess the effectiveness of lag screw fixation in mandibular fractures with respect to parameters such as stability of the occlusion, functional stability, infection rates, neurosensory deficit, ease of technique, and maximum interincisal opening.

Materials and Methods:

Our study was carried out on 13 patients with mandibular fractures. Selected cases were treated with lag screw technique and 2.7 mm titanium screws were used. Postoperative complications such as wound dehiscence, infection, neurosensory disturbance, nonunion, malocclusion, postoperative mouth opening, and occlusal discrepancies were assessed.

Results:

All the patients were male, aged between 17 and 50 years. The cause of the injury was road traffic accidents in all, except for two assaults. Our study of 13 cases of fractured mandible included five symphyses, five parasymphyses, two angle, and one body fracture cases. Our observation with open reduction and rigid internal fixation with 1–2 lag screws revealed close approximation of fractured fragments in all the cases, except in three patients who had mild discrepancy of occlusion.

Conclusion:

Lag screw technique provides good interfragmentary compression and restoration of premorbid anatomic alignment of fracture fragments. In displaced mandibular fractures, especially in oblique fractures, the use of lag screw has proven to be ideal. The complications were found to be low. It was concluded that the lag screw provided excellent stability and occlusion.

Titanium Lag Screw Versus Miniplate Fixation in the Treatment of Anterior Mandibular Fractures

PURPOSE

The use of plates for open reduction and internal fixation of mandibular fractures has become a widely accepted method in the past 3 decades. However, the anterior mandible is well suited to lag screw fixation owing to the thickness of its bony cortices. Hence, the purpose of the present study was to comparatively evaluate clinical outcomes of fixation using lag screws and miniplates in anterior mandibular fractures.

PATIENTS AND METHODS

Fifty patients reporting to the department of oral and maxillofacial surgery with noncomminuted anterior mandibular fractures were randomly divided into 2 groups of 25 patients each. Patients in group A were treated with 2.5-mm lag screws 22 to 26 mm in length and those in group B were treated with 2.0-mm 4-hole miniplates with a gap using monocortical screws. Subsequent follow-up was performed at 3, 6, 12, and 24 weeks postoperatively. The primary determinants included radiographic analysis of the fracture gap and biting efficiency of the patients in groups A and B. The secondary determinants included evaluation of duration of surgery, occlusion before and after injury, and postoperative complications. Results were evaluated using χ² and unpaired t tests.

RESULTS

The mean age of the patients in this study was 29.1 ± 8.32 years (range, 18 to 67 yr). The mean postoperative fracture gap was considerably larger in group B. The mean duration of surgery (minutes) was 37.60 ± 9.30 for group A and 47 ± 6.55 for group B. The difference was statistically significant (P = .001). The lag screw group showed faster improvement in biting efficiency compared with the miniplate group.

CONCLUSIONS

Lag screw fixation was found to have good stability and rigidity, was inexpensive, and was less time consuming in treating anterior mandibular fractures compared with miniplates.

A clinical prospective randomized comparative study on ostyeosynthesis of mandibular anterior fractures following open reduction using lag screws and miniplates

Introduction

The aim of the present study was to compare fixation of mandibular anterior fractures following open reduction using lag screws or miniplates.

Materials and Methods

This prospective study was conducted on 20 patients diagnosed with cases of displaced mandibular anterior fractures treated with open reduction and internal fixation. The patients were then randomly allocated to either of two groups - Group A: two 2.5 mm stainless steel lag screws were placed in 10 patients. Group B: two 2.5 mm miniplates were placed in 10 patients for the fixation of fractures. Subsequent follow-up was done on the 1^st day, 1^st, 4^th, and 36^th week postoperatively. During every follow-up, patient was assessed clinically for infection, malocclusion, loosening of plate/screw, malunion/nonunion, and masticatory efficiency. Radiographs (orthopantogram) were taken preoperative, 1^st, 4^th, and 36^th postoperative week to compare the osteosynthesis between the two groups. Pain was objectively measured using a visual analog scale. The data collected was subjected to unpaired t-test and paired t-test for statistical analysis.

Result

It was found that lag screw placement was rapid in comparison of miniplate placement. 3rd month postoperative assessment revealed Lag screw group to have better biting efficiency, and better bone healing which was statistically significant when compared with miniplate group.

Conculsion

Our study suggests that lag screw osteosynthesis can be advocated as a valid treatment modality in the management of mandibular symphysis and parasymphysis fractures.

Non-IMF mandibular fracture reduction techniques: A review of the literature

BACKGROUND

Intermaxillary fixation (IMF) techniques are commonly used in mandibular fracture treatment to reduce bone fragments and re-establish normal occlusion. However, non-IMF reduction techniques such as repositioning forceps may be preferable due to their quick yet adequate reduction. The purpose of this paper is to assess which non-IMF reduction techniques and reduction forceps are available for fracture reduction in the mandible.

METHODS

A systematic search was performed in the databases of Pubmed and EMBASE. The search was updated until February 2016 and no initial date and language preference was set.

RESULTS

14 articles were selected for this review, among them ten articles related to reduction forceps and four articles describing other techniques. Thus, modification and design of reduction forceps and other reduction techniques are qualitatively described.

CONCLUSION

Few designs of repositioning forceps have been proposed in the literature. Quick and adequate reduction of fractures seems possible with non-IMF techniques resulting in anatomic repositioning and shorter operation time, especially in cases with good interfragmentary stability. Further development and clinical testing of reduction forceps is necessary to establish their future role in maxillofacial fracture treatment.

Prospective study of treatment outcomes with lag screw versus Herbert screw fixation in mandibular fractures

The principle of axial compression for better adaptation of fracture segments, with the advantage of increased stability and early function, is a promising means of avoiding the bulky rigid plates used previously. This study was done to compare the treatment outcomes between Herbert screw and lag screw fixation in mandibular fractures. Thirty patients with oblique displaced or undisplaced mandibular fractures requiring open reduction and internal fixation with rigid screw fixation, under general anaesthesia, were included. Herbert screws were used in 15 patients (group 1) and lag screws were used in the other 15 patients (group 2). Patients were followed up at 1 week, 6 weeks, 3 months, and 6 months for postoperative occlusion, inter-fragmentary mobility, pain, nerve sensation, and isodensity values on panoramic radiographs. Postoperative occlusion, inter-fragmentary mobility, pain, and nerve sensation were similar in the two groups. Group 1 patients attained isodensity values similar to the final follow-up value much faster than group 2 patients (P<0.05). This study strongly suggests that the use of Herbert screws results in significantly faster healing as compared to lag screws, in terms of achieving higher isodensity values faster.

Complications of mandibular fracture: study of the treatment methods in calabar, Nigeria

OBJECTIVE

The plethora of techniques available for the treatment of mandibular fractures suggests that there is controversy regarding their definitive outcome. The purpose of this study was to clinically study the complications associated with the different treatment methods of mandibular fractures at the University of Calabar Teaching Hospital (UCTH), Nigeria.

METHODS

This was a three-year prospective study carried out at the Dental and Maxillofacial Clinic of the hospital. Patients who met the inclusion criteria had their data recorded in a proforma questionnaire.

RESULTS

Out of the 256 patients studied, 17.2% developed complications. Complications were commoner (70.5%) between ages 21 and 50 years. Thirty-five (79.5%) were males while nine (20.5%) were females with a male:female ratio of 4.9:1. Following treatment by closed reduction, conservative and open reduction, 16.6%, 17.2% and 20.7% had complications, respectively. Whereas occlusal derangement was the most common complication, numbness of the cheek and lower lip was recorded following all treatment methods.

CONCLUSION

Although the complications recorded in this patient population were managed during postoperative follow-up period, the methods of treatment available give good results, are cost-effective and patient compliance is good. This suggests that the older methods of treatment of mandibular fractures can still be used with reliability in contemporary dental practice.

Fixation of mandibular angle fractures: clinical studies

PURPOSE

The purpose of this study was to review the literature regarding the evolution of current thoughts on fixation of mandibular angle fractures (MAFs).

METHODS

An electronic search in PubMed was undertaken in August 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies from the last 30 years (from 1983 onwards) reporting clinical studies of MAFs.

RESULTS

The search strategy initially identified 767 studies. The references from 1983 onwards totaled 727 articles. Fifty-four studies were identified without repetition within the selection criteria. Two articles showing significance in the development of treatment techniques were included. Additional hand-searching yielded 13 additional papers. Thus, a total of 69 studies were included.

CONCLUSIONS

Prospective randomized controlled studies of MAFs repair techniques are scarce. The available data at best predict that complications are associated with all kinds of fixation techniques. The similar results of complications in studies using different methods of fixation indicate that biomechanics are only one factor to be considered when treating MAFs. A second fracture in the mandible (which was observed in the majority of the studies' population) can confound the outcome data because the fixation requirements of a double fracture are often different from those for an isolated fracture. It can be necessary additional effort intended for increase of stability when using biodegradable plate system to fixate MAFs. The use of 1.3 mm malleable miniplates was associated with an unacceptable incidence of plate fracture, suggesting that this is not the most adequate system to treat MAFs. The use of the 3D grid plates has shown good clinical results. The efficiency of locking miniplate system is yet to be proven because there are few clinical studies with its use to fixate MAFs, although they have shown good results. When considering the use of semirigid or rigid fixation systems, the use of two miniplates outweigh the advantages of the use of one reconstruction plate, although the use of miniplates is not recommended for displaced comminuted MAFs. Although it has been shown that absolute rigid fixation is not necessary for fracture healing, any system that provides superior stability without impacting negatively on other aspects of the procedure, i.e., time, exposure, and cost, should be favored. MAFs can be treated in a highly effective way and with a relatively low rate of complications with monocortical miniplate fixation. The large number of studies on the treatment of MAF reflects the fact that a consensus has not been reached for a single, ideal treatment method.

A comparative analysis of the efficacy of cortical screws as lag screws and miniplates for internal fixation of mandibular symphyseal region fractures: a randomized prospective study

The management of facial trauma is one of the most rewarding and demanding aspects of oral and maxillofacial surgery. Being the most prominent mobile bone of the facial skeleton, mandible fracture occurs more frequently than any other fracture. In this study, open reduction and internal fixation was performed for isolated mandibular symphyseal region fractures using cortical screws (as lag screws) in 40 patients and using miniplates in 40 patients. Clinical and radiological evaluations were made at 6 months postoperatively. Primary stability of fracture segments, postoperative swelling, restricted lip mobility, infection, wound dehiscence, implant removal, and mal-union or non-union of fracture segments was evaluated. Primary stability was achieved in 100% of cases treated with cortical screws, whereas for patients treated with miniplates, 97.5% attained primary stability, while one case (2.5%) showed persistent clinical mobility. Postoperative complications were noted in 13 (16.25%) of the total 80 patients. The duration of postoperative swelling was less in patients treated with cortical screws compared to patients treated with miniplates. It is concluded that cortical screw fixation is an effective procedure for the treatment of symphyseal region fractures, but the procedure is somewhat technically sensitive.

Anchor lag screw vs conventional lag screw in mandibular fractures: A series of 30 cases

Lag screw osteosynthesis is a well proven technique. Its application is limited by the fact that the spherical head of the screw act as wedge. Combining this screw with a bioconcave washer has broadened the range of applications for lag screw osteosynthesis in the maxillofacial region.

PURPOSE

The aim of the study was to compare the efficacy of anchor lag screw with conventional lag screw in anterior mandibular fractures.

PATIENTS AND METHOD

Thirty patients with anterior mandible fractures with no concomitant fractures, infection or extraoral communication, who visited our outpatient Department of Oral and Maxillofacial Surgery, were included in the study after obtaining their informed consent. Patients were randomly divided into two groups; where Group A underwent fixation using conventional lag screw and Group B anchor lag screw. The fixation system used included 2 mm titanium lag screws of sizes 25 mm, 27 mm and 30 mm and 3 mm titanium bioconcave washer. At each follow up visit, clinical data was collected detailing clinical presentation of healing and radiographic findings.

RESULTS

Radiographic features at post surgery evaluation indicated loss of bone contact around the screw head and bone resorption in five patients of Group A, thus causing loosening of lag screw whereas none of the patient in Group B, was found to have any such complication.

CONCLUSIONS

The findings support the hypothesis that bioconcave washer aids in holding up the farthest fragment at the interface of the fracture fragment. Application of bioconcave washer provides easy loading of lag screw.

Comparative analysis of osteosynthesis of mandibular anterior fractures following open reduction using 'stainless steel lag screws and mini plates'

INTRODUCTION

The purpose of this study was to compare the outcome of open treatment of mandibular fracture (symphysis or parasymphysis) using lag screw or mini plate clinically as well as radiologically in young (age range 12-45 years) and healthy individuals of poor socioeconomic status.

METHOD

This prospective study was conducted on 30 patients diagnosed as cases of displaced mandibular anterior fractures treated with open reduction and internal fixation. The patients were then randomly allocated to either of two groups--Group A: Two 2.5 mm stainless steel lag screws were placed in 15 patients. Group B: Two 2.5 mm stainless steel mini plates were placed in 15 patients for the fixation of fractures. Subsequent follow up was done on 2nd, 4th, 6th and 8th week postoperatively. During every follow up patient was assessed clinically for infection, malocclusion, loosening of plate/screw, sensory disturbance, plate fracture, malunion/non-union, devitalisation of associated dentoalveolar segment and masticatory efficiency. Radiographs were taken if necessary and patients were further assessed for any complaint. Pain was objectively measured using a visual analogue scale, bite force was measured using a bite force transducer at biweekly interval. The data collected was subjected to unpaired t test and paired t test for statistical analysis.

RESULTS

During follow up period a significant improvement in bite force was present in both the groups, with more improvement seen in the lag screw group (p < 0.01). There was a significant pain reduction present in the lag screw group (p < 0.01) and also masticatory efficiency showed a steadier improvement in lag screw group while mini plate group patients showed a tendency to masticate only food items of medium hard consistency.

CONCLUSION

The sample size is small to conclude lag screws are better than mini plates but the result of our study provides a basis for further studies done to conclude that the application of LAG SCREW is an effective, inexpensive, quick treatment modality to accelerate healing of fresh, displaced mandibular anterior fracture.

Can an arch bar replace a second lag screw in management of anterior mandibular fractures?

PURPOSE

To evaluate the efficacy of using a single lag screw combined with an arch bar in the management of anterior mandibular fractures and to compare this method with the traditional application of 2 lag screws.

MATERIALS AND METHODS

We designed and implemented a randomized clinical trial and enrolled a sample of patients with anterior mandibular fractures. Twenty adult male patients were randomly divided into 2 equal groups according to the number of lag screws used for fracture fixation after securing the occlusion with intermaxillary fixation. In group A, the fractures were treated using 2 lag screws. In group B, the fractures were treated using a single lag screw and an arch bar on the teeth, spanning the fracture line. Clinical and radiographic evaluations were used to evaluate the efficacy of each fixation method immediately and at 2 and 4 months postoperatively.

RESULTS

The clinical examination showed stable fixation with no mobility or infection in all cases. One patient in group A showed a slight occlusal discrepancy that was managed with occlusal adjustment. The pretraumatic occlusal relationship of all other patients was re-established. Postoperative radiographs showed properly reduced fracture segments with gradual bone healing. No significant difference was noted (P > .05) between the 2 groups in the development of postoperative complications.

CONCLUSIONS

The use of 1 lag screw in conjunction with an arch bar across the fracture line is rigid and stable enough to manage anterior mandibular fractures without the need for supplemental intermaxillary fixation. The use of a single lag screw offers several advantages compared with the traditional use of 2 lag screws. These advantages include decreased cost, use of materials, healing time, and risk of associated morbidity.

Transgingival lag-screw osteosynthesis of alveolar process fracture

Fracture of the alveolar process is a common injury. In some cases, traditional fixation may not be possible. The teeth needed for splinting or mandibulo-maxillary fixation may be missing. The fracture line and soft tissue injury may jeopardize the blood supply of the broken bone. In these extreme and rare situations, the best rehabilitation is needed to avoid the loss of hard and soft tissues, and a secondary reconstruction is required. Between January 2003 and December 2006, of 468 cranio-facial trauma patients studied, alveolar process fracture was reported in 28 (6%) cases. In six (1%) cases, the anatomy of the fracture lines, and the position and number of the remaining teeth made splinting and mandibulo-maxillary fixation impossible. Patients were treated with a transgingival lag-screw (TLS) osteosynthesis. All patients healed well with no complications. There was no bone or tooth loss in the surgical area, and broken fragments were not absorbed. The TLS technique is recommended for alveolar fractures when the blood supply is jeopardized and dental splinting or mandibulo-maxillary fixation is not possible. There is no need for flap reflection.

Evaluation of stress patterns generated by reduction forceps within a photoelastic mandibular model

INTRODUCTION

Little attention has been paid to the mechanical effects of fracture reduction forceps.

AIM

This study aims to evaluate the stress patterns within the fractured mandible generated by reduction forceps.

MATERIAL AND METHODS

Thirty-six mandibular models were fabricated using a photoelastic resin. Each of the three sets of mandibular models was osteotomized according to one of three different fracture types. After reducing the cut segments, reduction forceps were placed into different engagement holes to compress the segments. Photoelastic stress analysis was used to visualize the stress patterns within the fractured mandibular models as generated by the reduction forceps.

RESULTS

In the case of symphyseal or parasymphyseal fractures, an optimum distribution of stresses over the fracture site was achieved when placing the reduction forceps more than 12mm away from either side of the fracture line, between the midway level of the mandibular height (bisecting the mandible) and 5mm below this level. In the case of body fractures, optimum stress distribution was achieved when the reduction forceps were placed more than 16mm from the fracture line at the midway level.

CONCLUSION

Correct use of the reduction forceps helps to provide a precise three-dimensional reduction for mandibular fractures.

Self-adapting washer system for lag screw fixation of mandibular fractures. Part II: In vitro mechanical characterization of 2.3 and 2.7 mm lag screw prototypes and in vivo removal torque after healing

The aim of this study was to mechanically characterize self-tapping 2.3 and 2.7 mm titanium lag screw prototypes which are part of the newly developed 'self-adapting washer' maxillofacial lag screw osteosynthesis system. In vitro in a screw testing machine the insertion torque, maximum locking torque and axial force and the ultimate torsional strength were assessed. In vivo in six miniature pigs using a mandibular symphyseal fracture model, the removal torques after 3 and 6 months of healing were measured. Additionally the bone-metal contact (BMC) of the screws was assessed histometrically. The maximum insertion torque (0.185 Nm) was far below the mechanical limits of the screws (2.3 mm = 0.96 Nm, 2.7 mm = 1.6 Nm). A tightening of the 2.7 mm screw with an axial force of 1000 N and of the 2.3 mm screw with 500-550 N leaves a safety margin of approximately one-third on the ultimate torsional strength. Clinically these values permit the use of two 2.3 mm lag screws or one 2.7 mm lag screw in mandibular symphysis fractures since 1000 N tensile axial force are required in this indication. During screw removal after 6 months healing, torque levels close to the mechanical limits of the screws were recorded and screw failures were observed. This failure rate may have been due to the BMC of 49.8% which was in the range of titanium dental implants. Accordingly the screw heads were reinforced to prevent fractures.

Fixation of mandibular body osteotomies using biodegradable amorphous self-reinforced (70L:30DL) polylactide or metal lag screws: an experimental study in sheep

Mandibular body osteotomies were fixed in nine sheep using new totally amorphous (70L:30DL), self-reinforced, polylactide (SR-PLA) lag screws and in nine sheep using standard stainless steel lag screws. No intermaxillary fixation was used. During follow-up, radiological, histological and microradiological studies were undertaken at 3, 6, 12 and 24 weeks. In both groups, all osteotomies consolidated at similar rates and no adverse reaction to the screws was seen. However, displacements of the fixed osteotomy fragments were common in both groups during the first 3 weeks. The biocompatibility of SR-PLA during the follow-up period was found to be good. Only initial signs of biodegradation were seen. The results of this study indicate that (70L:30DL) SR-PLA has potential for use as a fixation screw material in oral and maxillofacial surgery, and that further studies using this material are justified.

The self adapting washer for lag screw fixation of mandibular fractures: finite element analysis and preclinical evaluation

Besides rigid fixation, lag screws have distinct advantages compared with plates in appropriate indications in mandibular fractures. However, in current lag screw systems, the relatively small area of the screw head has to transfer the tensile force which can exceed 1000 N in the symphysis, to the thin cortical bone plate. Countersinking, which is obligatory in most systems, will weaken the cortical plate. Finite element analysis (FEA) revealed that load in this situation can exceed the normal tensile strength of metal and bone. Consequently, a new washer was constructed which both increased the supporting surface and did not require countersinking. The washer is self adapting (SAW) to the cortical plate in a defined position, forming a ball and socket joint with the screw head. Using the FEA model, a ten-fold reduction in load on bone and metal was observed with the new washer. In a miniature pig mandibular symphysis fracture model, the clinical applicability and a favourable histological reaction were demonstrated, compared with conventional lag screw designs.

Lag-screw fixation of anterior mandibular fractures using biodegradable polylactide screws: a preliminary report

PURPOSE

The purpose of this study was to evaluate the utility of biodegradable, self-reinforced poly-L-lactide screws (SR-PLLA) for lag-screw fixation of anterior mandibular fractures.

PATIENTS AND METHODS

SR-PLLA lag-screws were used to stabilize anterior mandibular fractures in 11 patients. Maxillomandibular fixation was used to treat concomitant mandibular condyle fractures for 2 weeks in four patients and for 1 and 5 weeks in two patients. Clinical and radiologic follow-up lasted for 6 months in 36% of patients and for 1 year in 64%.

RESULTS

Healing of all anterior fractures was uneventful, with no displacement or delay of bony union. No adverse reactions to the biodegradable screws were seen during follow-up.

CONCLUSION

Biodegradable SR-PLLA screw fixation seems to be a new and promising way of treating anterior mandibular fractures.

Biodegradable polylactide plates and screws in orthognathic surgery: technical note

In orthognathic surgery, the bone fragments are usually fixed with metallic plates and screws. Metallic devices other than titanium plates are usually removed after the osteotomy has consolidated, which often requires general anaesthesia. Titanium plates, supposed to be biotolerable, have been introduced in order to overcome this need for secondary intervention. However, due to corrosion, titanium particles have been found in scar tissue covering these plates and in locoregional lymph nodes. Therefore, their removal is also advocated. Self-reinforced poly (L-lactide) homopolymer (PLLA) and poly (L/D-lactide) stereocopolymers with a L/D molar ratio up to 85/15 have sufficient strength to overcome the need for additional support for the fixation of fractures. The plates can be bent at room temperature. The surgical technique and early results of a case of bimaxillary surgery and genioplasty fixed with bioresorbable material without postoperative rigid maxillomandibular fixation are reported.