Mandibular fractures treated with maxillomandibular fixation screws (MMFS method)

The purpose of the treatment of mandibular fractures is to restore proper dental occlusion and stable temporomandibular joint movement, as well as the reduction of the displaced fracture. Consideration must be given to the selection of the most appropriate surgical and rehabilitation methods in such patients. Typical surgical methods for the treatment of mandibular fractures include the arch bar method or plating at the location of the fracture combined with fixing the mandible to the maxilla using the arch bar method. However arch bars and circumdental wires, which require teeth for fixation, damage teeth and periodontal tissue, and tend to be uncomfortable for patients during the fixation period. Moreover, daily maintenance of oral hygiene is difficult for patients with an arch bar. Surgeons are also exposed to the risk of blood-transmitted diseases through skin punctures by wires when affixing these devices. For these reasons, we chose to study the potential of the MMFS method, which is thought to lessen all of the following problems: tissue damage, operating time, patient discomfort, and possible exposure to percutaneous infectious disease due to puncture of gloves and skin by the wires. We demonstrated the utility of the MMFS method in the present study.

Evaluation of upper lip hypoesthesia with a trigeminal somatosensory-evoked potential following Le Fort I osteotomy in combination with mandibular osteotomy

PURPOSE

The purpose of this study was to objectively evaluate hypoesthesia of the upper lip following Le Fort I osteotomy in combination with mandibular osteotomy with trigeminal somatosensory evoked potential (TSEP).

SUBJECTS AND METHODS

The subjects consisted of 25 patients with mandibular prognathism with maxillary retrognathism mandibular prognathism with or without asymmetry, who underwent Le Fort I osteotomy in combination with sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO). Trigeminal nerve hypoesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The electrodes were placed exactly above the highest point of the vermilion border and on the mucosa of the upper lip. An electroencephalograph recording system (Neuropack Sigma; Nihon Koden Corp., Tokyo, Japan) was used to analyze the potentials. Each patient was evaluated preoperatively and then postoperatively at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year.

RESULTS

The average measurable period and standard deviation of TSEP of the upper lip was 7.8 +/- 10.7 weeks following Le Fort I osteotomy, TSEP of the lower lip was 4.6 +/- 9.2 weeks in the patients who underwent SSRO with Le Fort I osteotomy, and 1.2 +/- 0.4 weeks in the patients who underwent IVRO with Le Fort I osteotomy.

CONCLUSION

This study objectively proved that hypoesthesia could appear in the upper lips following Le Fort I osteotomy with TSEP. The measurable period for the upper lip following Le Fort I osteotomy tended to be longer than that for the lower lip in the patients who underwent SSRO and IVRO with Le Fort I osteotomy.

Long-term skeletal and soft-tissue responses after advancement genioplasty

INTRODUCTION

The objectives of this cephalometric study were to assess the skeletal stability of advancement genioplasty 3 years after surgery and to evaluate the predictability of soft-tissue changes.

METHODS

The subjects comprised 21 consecutive patients who had no additional orthognathic surgical procedures. Lateral cephalograms were taken at 5 times: immediately preoperative, immediately postoperative, 6 months postoperative, and 1 and 3 years postoperative.

RESULTS

Mean surgical advancement at pogonion was 8.4 mm. Three years after surgery, mean relapse at pogonion was 8% of the surgical advancement. Part of this change was most likely due to bone remodeling. No patient demonstrated a clinically significant postoperative change at pogonion. The soft tissue of the chin was found to follow bony movement in a ratio of 0.9:1. Great individual variability was observed. The mentolabial fold depth increased as a result of the treatment. Effects of advancement genioplasty on the lips were small.

CONCLUSIONS

A prediction ratio based on long-term skeletal changes is likely to generate an estimate that is more appropriate to present to the patient.

Oral Appliances and Maxillomandibular Advancement Surgery: An Alternative Treatment Protocol for the Obstructive Sleep Apnea-Hypopnea Syndrome

PURPOSE

The present study comprises a retrospective evaluation of the potential application of mandibular repositioning appliance (MRA) therapy preceding maxillomandibular advancement (MMA) surgery in the treatment of the Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS). Our initial experiences with a new surgical protocol, in which MRA therapy serves as a predictor for success of MMA surgery, are reported.

PATIENTS AND METHODS

Forty-three consecutive patients with OSAHS treated with MRA therapy were considered for inclusion (mean+/-SD; Apnea-Hypopnea Index [AHI]=27+/-20; age=53+/-9 years). All patients displaying a substantial improvement in their AHI with MRA therapy (ie,>50% reduction) who preferred surgical rather than "prosthetic" advancement of the mandible were offered MMA surgery. Accordingly, 4 out of 43 patients were treated with MMA surgery. The AHI was used as the primary outcome measure, with MMA surgery being considered successful in case of a postoperative AHI <5.

RESULTS

All 4 patients included displayed substantial improvement in their AHI following MRA therapy. Moreover, in 3 patients MRA therapy resulted in a post-treatment AHI <or=5. With respect to the primary outcome measure, successful OSAHS management was attained in all 4 patients following MMA surgery.

CONCLUSION

Results from the 4 patients included in the present study suggest that MRA therapy might be a good predictor for the success of MMA surgery in OSAHS management. Although confirmation in a larger study sample is indicated, we conclude that patients with a substantial reduction in baseline AHI with MRA therapy appear to be candidates for MMA surgery.

A simple method for bone positioning of mandibular segments

A simple bone-positioning technique is reported, using a combination of bone plates and a flexible tube filled with acrylic polymer. The flexible tube is solidified by injection of acrylic monomer. This technique is applicable for bone positioning after mandibular resection as well as positioning of the proximal segment after sagittal split ramus osteotomy. This technique has the advantages of greater simplicity and flexibility compared to previously reported methods of bone positioning.

A 2-stage procedure combining maxillary advancement by distraction technique with mandibular setback surgery in patients with cleft lip and palate

A 2-stage procedure combining maxillary advancement by distraction technique with mandibular setback surgery was used to correct jaw deformities in 5 patients with severe maxillary retrusion secondary to cleft lip and palate. First, a Le Fort I maxillary osteotomy was performed. Immediately after maxillary distraction, the distraction device was removed. The advanced maxilla was fixed with miniplates after adjusting the length and direction of advancement, and mandibular setback surgery was performed simultaneously to obtain a normal occlusal relationship. This 2-stage procedure resulted in stable occlusion and a markedly improved facial profile.

In vitro comparison of biomechanical characteristics of sagittal split osteotomy fixation techniques

The aim of the present study was to compare the biomechanical stability of 10 different fixation methods used in sagittal split osteotomy. Twenty-five fresh sheep mandibles were stripped of all soft tissues and sectioned at the midline. A sagittal split osteotomy with 5mm advancement was performed on each hemimandible. The hemimandibles were randomly divided into 10 groups of 5, and then fixed with 5 different bicortical screws, 4 different miniplates with or without bicortical screws, and 1 resorbable screw configuration. All specimens were mounted on a specially designed 3-point biomechanical test model and compression loads were applied using the Lloyd LRX testing machine until 3mm displacement was reached. Load/displacement data were gathered and compared using the Mann-Whitney U-test with Bonferroni correction (P<0.01). The 3 bicortical screws in an inverted backward-L pattern provided the most biomechanical stability of the screw patterns tested. The miniplate fixed obliquely with 2 bicortical screws in the proximal segment provided the most biomechanical stability of the miniplate groups.

Management of an unusual maxillary dentoalveolar fracture: a case report

The purpose of this case report was to describe the management of a trauma-induced maxillary dentoalveolar fracture of the right maxilla in an 8-year-old boy. The child presented with swelling of the right maxillary region, difficulty in chewing and closing the mouth, and a sutured laceration on the cheek. Complete palatal displacement of the fractured fragment involving the deciduous canine and molars was observed clinically and confirmed by radiological examination. The fracture was reduced and stabilized using a custom-fabricated, open-cap acrylic splint with modified interdental wiring under general anesthesia.

Mandibular mechanics after osteotomy and distraction appliance placement I: Postoperative mobility of the osteotomy site

PURPOSE

Fixation at the osteotomy site for mandibular distraction osteogenesis (DO) is probably not rigid, especially during mastication. Micromotion may affect the course of DO. This study aimed to measure the mobility of the fresh distractor-fixed osteotomy site in response to mastication and masticatory muscle stimulation.

MATERIALS AND METHODS

Twenty-eight domestic pigs, 6 to 8 weeks old, underwent osteotomy of the right mandible and placement of a distractor appliance. Immediately after surgery, displacement at 3 different locations (superior-lateral, inferior-lateral, and inferior-medial) of the osteotomy site was assessed using ultrasound piezoelectric crystals or differential variable reluctance transducers (DVRTs). The amount of lengthening or shortening at each location was measured during mastication and muscle stimulation. Displacement was also measured for bilateral osteotomy during muscle stimulation from a subgroup of 12 pigs.

RESULTS

The osteotomy site demonstrated significant mobility during power strokes of mastication with an average magnitude of 0.3 to 0.4 mm. Distinct patterns of displacement were associated with different locations, and the patterns varied between chewing sides. The most common pattern was lengthening at the superior-lateral and shortening at both inferior sites. Similar amounts of displacement were observed during the stimulation of jaw-closers (masseter and medial pterygoid), but the patterns produced by these muscles did not completely explain the masticatory pattern. Opening the osteotomy to 1.5 mm did not alter the displacements observed during muscle stimulation. Bilateral osteotomy tended to decrease displacement.

CONCLUSIONS

The study demonstrates that during mastication and masticatory muscle stimulation, an acute mandibular osteotomy site is mobile despite fixation by a distractor appliance.

A new attachment for proximal segment positioning for bimaxillary dysgnathic surgery--technical note

BACKGROUND

The frequent insertion of self-tapping screws for securing the proximal positioning plate in bimaxillary osteotomy often cause loosening of screws and plate, which produces incorrect repositioning. In this article, a newly developed base-attachment for a T-shaped proximal positioning plate for bimaxillary osteotomy is presented.

MATERIAL

The base-attachment set consists of a titanium base-attachment and two titanium tapped screws. The attachment has a shallow depression having the same shape as the basal part of the positioning plate.

METHOD

The base-attachment is secured by self-tapping screws until the end of the procedure, and the T-shaped proximal positioning plate is placed and secured by two titanium-tapped screws.

RESULT

By using this base-attachment, the T-shaped plate can be easily placed repeatedly without difficulty.

CONCLUSION

This base-attachment set may be useful for the frequently repositioned proximal plate in bimaxillary osteotomy.

Mandibular mechanics following osteotomy and appliance placement II: Bone strain on the body and condylar neck

PURPOSE

The purpose of this investigation was to determine if the mechanical environment of the mandible is changed by osteotomy and fixation, as assessed by the measurement of bone strain on the condylar neck and mandibular corpus.

MATERIALS AND METHODS

Immediately following unilateral mandibular osteotomy and distractor placement, strain gauges were attached directly to the corpus and condylar neck in a sample of domestic pigs. Bone strains were recorded during mastication and muscle stimulation. Comparisons of principal strain magnitudes and orientations were made between sides and between the osteotomy sample and a control database.

RESULTS

The animals preferred to chew on the non-osteotomy side. Corpus strains were higher for osteotomy-side chewing but were comparable to the control database, regardless of chewing side. For the condyle, compared with the control database and the non-osteotomy side, the osteotomy side was underloaded in compression. Furthermore, the orientation of compressive strain was highly variable and more horizontally oriented than that of control and non-osteotomy condyles. Stimulation of the masseter and medial pterygoid loaded the mandible to normal levels.

CONCLUSION

Masticatory behavior was altered, probably as a combined result of disruption of the occlusion, changes in muscle recruitment, and probable loss of sensory feedback. However, neither these changes nor damage to the muscles explain the decrease and reorientation of compressive strain on the condylar neck. Alternatively, the modified strain pattern could have arisen from positional instability of the proximal bone fragment.

Stability of Skeletal Class III Malocclusion After Combined Maxillary and Mandibular Procedures: Titanium Versus Resorbable Plates and Screws for Maxillary Fixation

PURPOSE

The aim of this study was to evaluate skeletal stability after double jaw surgery for correction of skeletal Class III malocclusion to assess if there were any differences between resorbable plate and screws and titanium rigid fixation of the maxilla.

PATIENTS AND METHODS

Twenty-two Class III patients had bilateral sagittal split osteotomy for mandibular setback stabilized with rigid internal fixation. Low level Le Fort I osteotomy for maxillary advancement was stabilized with conventional titanium plate and screws in 12 patients (group 1) and with resorbable plate and screws in 10 patients (group 2). Lateral cephalograms were taken before surgery, immediately postoperatively, 8 weeks after surgery, and 1 year postoperatively.

RESULTS

Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary stability was excellent in both groups. In group 1 no significant correlations were found between maxillary advancement and relapse. In group 2, significant correlations were found between maxillary advancement and relapse at A point and posterior nasal spine. No significant differences in postoperative skeletal and dental stability between groups were observed.

CONCLUSION

Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure for maxillary advancements up to 5 mm independently from the type of fixation used to stabilize the maxilla. Resorbable devices should be used with caution for bony movements of greater magnitude until their usefulness is evaluated in studies with large maxillary advancements.

The Incidence of Postoperative Wound Healing Problems Following Sagittal Ramus Osteotomies Stabilized With Miniplates and Monocortical Screws

PURPOSE

Titanium plates and monocortical screws are commonly used to stabilize the mandible following sagittal split ramus osteotomies. Despite widespread use of this type of fixation, there is a paucity of large studies evaluating the infection rate and need for hardware removal.

MATERIALS AND METHODS

This study is a retrospective cohort evaluation of 1,066 consecutive mandibular sagittal ramus osteotomies in 533 patients, performed between January 2002 and December 2003. All osteotomies were stabilized with 4-hole miniplates and 2.0 mm x 5.0 mm monocortical screws. Study variables included disturbances of wound healing, age, gender, plate and screw position, direction of mandibular movement, adjunctive procedures performed, and the patient's medical history. Data were collected by chart and radiographic review. The above variables were analyzed using Fisher's exact test, Chi-square, Cochran-Armitage Trend Test, and multiple logistic regression.

RESULTS

Of 533 patients 26% (138) demonstrated wound healing problems. This occurred in 15% of all 1,066 osteotomy sites. 6.5% of plates required removal in 10% of patients. In no case did disturbance of wound healing or plate removal result in non-union or relapse of the osteotomy. Wound healing problems were fewer when mandibular osteotomies were done in conjunction with maxillary surgery (18.9% versus 29.1%). Disturbances of wound healing were not related to the direction of movement of the mandible and were lower when hardware was placed closer to the inferior border.

CONCLUSION

An overall low incidence (6.5%) of hardware infection requiring plate removal was found in this study. Screw proximity to the osteotomy site did not correlate with higher rates of healing problems, but there was a statistically significant trend of fewer disturbances of healing when the hardware was placed closer to the inferior border of the mandible.

Short- and long-term skeletal relapse after mandibular advancement surgery

This study analyzes short- and long-term skeletal relapse after mandibular advancement surgery and determines its contributing factors. Thirty-two consecutive patients were treated for skeletal Class II malocclusion during the period between 1986 and 1989. They all had combined orthodontic and surgical treatment with BSSO and rigid fixation excluding other surgery. Of these, 15 patients (47%) were available for a long-term cephalography in 2000. The measurement was performed based on the serial cephalograms taken preoperatively; 1 week, 6 months and 14 months postoperatively; and at the final evaluation after an average of 12 years. Mean mandibular advancement was 4.1 mm at B-point and 4.9 mm at pogonion. Representing surgical mandibular ramus displacement, gonion moved downwards 2 mm immediately after surgery. During the short-term postoperative period, mandibular corpus length decreased only 0.5 mm, indicating that there was no osteotomy slippage. After the first year of observation, skeletal relapse was 1.3 mm at B-point and pogonion. The relapse continued, reaching a total of 2.3 mm after 12 years, corresponding to 50% of the mandibular advancement. Mandibular ramus length continuously decreased 1 mm during the same observation period, indicating progressive condylar resorption. No significant relationship between the amount of initial surgical advancement and skeletal relapse was found. Preoperative high mandibulo-nasal plane (ML-NL) angle appears to be associated with long-term skeletal relapse.

Biodegradable fixation of mandibular fractures in children: stability and early results

OBJECTIVE

The aim of this study was to assess the safety and efficiency of biodegradable self-reinforced (SR-PLDLA) bone plates and screws in open reduction and internal fixation of mandible fractures in children.

STUDY DESIGN

Thirteen patients (5 female, 8 male; mean age 12 years, range 5-16 years) were operated on various fractures of the mandible (2 symphyseal, 6 parasymphyseal, 4 body, 3 angle, 1 ramus, 2 condylar fractures). The mean follow-up time was 26.4 months (range 10.9-43.4 months). Intermaxillary fixation was applied in cases with concomitant condylar fractures up to 3 weeks.

RESULTS

Primary healing of the fractured mandible was observed in all patients. Postoperative complications were minor and transient. The outcome of the operations was not endangered. Adverse tissue reactions to the implants, malocclusion, and growth restrictions did not occur during the observation period.

CONCLUSIONS

Pediatric patients benefit from the advantages of resorbable materials, especially from faster mobilization and the avoidance of secondary removal operations. Based on these preliminary results, self-reinforced fixation devices are safe and efficient in the treatment of pediatric mandible fractures. However, further clinical investigations are necessary to evaluate the long-term reliability.

Mandibular fracture reduction without intraoperative intermaxillary fixation: a technique using two modified reduction forceps

This case report demonstrates a technique that is useful for precompressing mandibular fractures and obtaining anatomical reduction of the fracture edges without the use of peroperative intermaxillary fixation (IMF) in a mandibular fracture by using two modified reduction forceps. The first forcep is positioned at the inferior mandibular border and the other in the neutral zone where it is an ideal location to place a fixation plate in mandibular fractures. This technique is indicated for the anatomic reduction in mandibular fractures of the partial dentate patient.

Treatment of a mandibular fracture with biodegradable plate in an infant: report of a case

Mandibular fractures in infants are rare. Different methods have been described for treatment of fractures of the mandible in infants. Internal fixation of a mandibular fracture with a biodegradable plate in an 8-month-old baby is described. In addition, choices of treatment modality in such cases are discussed.

A modified repositioning system for segmental resection of the mandible

Mandibular reconstruction is required after segmental resection of the mandible. Several techniques have been proposed but have several drawbacks. A modified system (based on Leibinger's titanium-positioning system) that can reposition the residual mandible easily and accurately without interfering with the reconstructive procedure was developed. This system has been used successfully in more than 10 patients, with no complications.

Transoral 2.0-mm Locking Miniplate Fixation of Mandibular Fractures Plus 1 Week of Maxillomandibular Fixation: A Prospective Study

PURPOSE

In this study, a 2.0-mm locking miniplate (LMP)/screw system was assessed in the treatment of mandibular fractures with a 1-week period of maxillomandibular fixation (MMF).

PATIENTS AND METHODS

Fifty mandibular fractures in 34 patients with a mean of 6.97 days of MMF were included in the study. The 2.0-mm LMPs were adapted along Champy's line of ideal osteosynthesis and secured with four 8.0-mm locking monocortical screws. All patients were followed for a minimum of 6 weeks. The incidence of soft tissue infections, nonunion, malunion, malocclusion, osteomyelitis, nerve injury, and tooth damage was prospectively assessed.

RESULTS

Primary bone healing was achieved in 98% of cases. Three complications (6%) were observed. Two minor complications of intraoral wound dehiscence and malocclusion were noted. A fibrous nonunion requiring 3 additional weeks of MMF was noted. No evidence of malunion, osteomyelitis, plate fracture, iatrogenic nerve injuries, or dental injuries was noted.

CONCLUSIONS

A single 2.0-mm LMP placed along Champy's line of ideal osteosynthesis with four 8-mm monocortical locking screws plus 1 week of MMF fixation is a reliable and effective treatment modality for mandibular fractures.

Intra-articular ramus ostectomy combined with costochondral grafting for the treatment of recurrent ankylosis of the mandible

PURPOSE

This report seeks to demonstrate a technique for treating recurrent ankylosis of the mandible by creating a functional false joint at a level distal to the original joint.

PATIENTS AND METHODS

This is a retrospective study involving patients treated between 1999 and 2003. Under general anaesthesia the ramus was exposed via a submandibular approach and a block of bone was removed from it inferior to the sigmoid notch. Temporary intermaxillary fixation was applied. A costochondral graft was interposed between the resected ends of bone and secured with mini-plates. Postoperatively intermaxillary fixation was maintained for 3 days after which the jaw was actively mobilized.

RESULTS

The technique was used in the treatment of six patients with recurrent ankylosis of the mandible ranging in age from 9 to 38 years. Follow-up was between 1 and 4 years. All the patients had a satisfactory interincisal opening ranging from 25 to 35 mm.

CONCLUSION

The technique does not require the exposure of the ankylosed joint proper but instead creates a false and functional joint at a lower level. It also permits lengthening and advancement of the mandible.

An In Vitro Comparison of an Adjustable Bone Fixation System

PURPOSE

The purpose of this study was to biomechanically compare an adjustable plating system and several variations with an inverted-L pattern of 3 bicortical screws to fix a bilateral sagittal split osteotomy.

MATERIALS AND METHODS

Sixty polyurethane mandible replicas (Synbone, Laudquart, Switzerland) were used in this study. Ten uncut mandibular replicas served as control models. Fifty experimental synthetic mandibles had bilateral sagittal split osteotomies created with a 7-mm advancement. Fixation modalities included 3 bicortical screws in an inverted-L pattern, a 4-hole sagittal split plate with adjustable slider (slide 0), an adjustable plate with an additional bicortical screw (slide 1), an adjustable plate with 2 additional bicortical screws (slide 2), and an adjustable plate with 3 additional bicortical screws (slide 3). The alloplastic mandibles were secured in a custom fabricated jig and subjected to vertical loads at the incisal edge and torsional loading at the molar region by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. Mechanical deformation data within a 0- to 900-N range were recorded. Yield load, yield displacement, and stiffness were determined. Means and standard deviations were derived and compared for statistical significance using a Fisher's Protected Least Significant Differences Test with a confidence level of 95% (P < .05). Second-order best-fit polynomials were created for the experimental data curves.

RESULTS

For incisal edge loading, the control was significantly greater for yield load than the experimental models. No significant difference was noted between slide 0, slide 1, and slide 2, but significant differences were seen with slide 3 and the inverted-L. There were no significant differences between slide 1, slide 2, slide 3, and inverted-L. For molar load, the control was significantly different than the experimental models. However, there was no significant difference between the experimental models.

CONCLUSIONS

Mandibular advancements of 7 mm in a synthetic mandible fixed with a 4-hole sagittal split plate with adjustable slider alone is resistant to torsional forces and comparable to that seen with 3 bicortical screws placed in an inverted-L fashion. However, when loading at the incisal edge, additional bicortical screws are necessary to achieve the similar resistance to vertical load as that seen with 3 bicortical screws.