Comparison of stability of absorbable and titanium plate and screw fixation for sagittal split ramus osteotomy

Six unembalmed adult sheep mandibles were stripped of all soft tissues and sectioned at the midline. Each side had a sagittal split ramus osteotomy (SSRO) and was advanced 5 mm. Six of the hemimandibles were fixed with four-hole extended titanium miniplates and titanium screws, and the other six were fixed with four-hole extended absorbable plates and absorbable screws. All specimens were mounted in a servohydraulic testing unit, and a range of forces (0-140 N) was applied. Displacement of each proximal segment was recorded at 10 N increments from 0 to 140 N. Values for the two groups were compared using the Mann-Whitney U-test, and significant differences in displacement were seen only at loads between 10 and 50 N. The results indicate that when absorbable miniplates are used intermaxillary fixation may be necessary to stabilise the bony fragments in the early postoperative period.

Stability of skeletal class III malocclusion after combined maxillary and mandibular procedures: rigid internal fixation versus wire osteosynthesis of the mandible

PURPOSE

The aim of this study was to evaluate skeletal stability after double-jaw surgery for correction of skeletal Class III malocclusion to assess whether there were any differences between wire and rigid fixation of the mandible.

PATIENTS AND METHODS

Thirty-seven Class III patients had Le Fort I osteotomy stabilized with plate and screws for maxillary advancement. Bilateral sagittal split osteotomy for mandibular setback was stabilized with wire osteosynthesis and maxillomandibular fixation for 6 weeks in 20 patients (group 1) and with rigid internal fixation in 17 patients (group 2). Lateral cephalograms were taken before surgery, immediately after surgery, 8 weeks after surgery, and 1 year after surgery.

RESULTS

Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary sagittal stability was excellent in both groups, and bilateral sagittal split osteotomy accounted for most of the total horizontal relapse observed. In group 1, significant correlations were found between maxillary advancement and relapse at the posterior maxilla and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. In group 2, significant correlations were found between mandibular setback and intraoperative clockwise rotation of the ramus and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. No significant differences in postoperative skeletal and dental stability between groups were observed except for maxillary posterior vertical position.

CONCLUSIONS

Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure independent of the type of fixation used to stabilize the mandible.

Comparative study of locking plates in mandibular reconstruction after ablative tumor surgery: THORP versus UniLOCK system

PURPOSE

This retrospective study compared 2 types of rigid locking plates (THORP and UniLOCK; Stratec Medical, Oberdorf, Switzerland) in 107 patients undergoing reconstruction for bridging mandibular defects following ablative tumor surgery.

PATIENTS AND METHODS

From January 1993 to December 2000, 107 patients were reconstructed following ablative tumor surgery with 57 THORP plates and 50 UniLOCK plates. Study follow-up ranged from 18 to 87 months (average, 32 months). Complications were categorized into delayed wound healing, infection, plate exposure, and plate fracture, taking into account the type and timing of reconstruction.

RESULTS

Overall type and number of complications show no statistically significant differences between THORP and UniLOCK groups. Infection was the most frequent type of complication (THORP, 30; UniLOCK, 32). Others included delayed wound healing (THORP, 13; UniLOCK, 12), plate exposure (THORP, 8; UniLOCK, 7), and plate fracture (THORP, 5; UniLOCK, 1). Plates were removed in 22 THORP and 11 UniLOCK plates. The most frequent reason for plate removal in both groups was infection. Other reasons for plate removal include tumor recurrence, plate fracture, plate exposure, or a combination of reasons.

CONCLUSIONS

THORP and UniLOCK plates do not present statistically significant differences in the parameters studied. Nevertheless, the UniLOCK group had slightly better results. Considering that the THORP system is much bulkier and its screws bigger, our results lead to the conclusion that bridging osteosynthesis with a 2.4 UniLOCK system is adequate for plate reconstruction of mandibular defects.

Closed treatment of condylar fractures by intermaxillary fixation with thermoforming plates

We report a new intermaxillary fixation (IMF) method for condylar fractures using a thermoforming plate. Fifteen cases of condylar fracture were selected and thermoforming plates were applied. The patient's recover was uneventful in all 15 cases, and the period of IMF ranged from 7 to 17 days, (mean 12) for the following 7 days IMF was used only at night together with functional jaw training during the day. The outcome was good. IMF using a thermoforming plate may be a useful technique for selected condylar fractures.

Complications of Bicortical Screw Fixation Observed in 482 Mandibular Sagittal Osteotomies

Bicortical screw fixation after bilateral sagittal split osteotomy (BSSO) of the mandible is commonly used in orthognathic surgery and allows many advantages compared with osteosynthesis wires and maxillomandibular fixation. Complications include early loosening, hardware exposition, skeletal instability or early relapses, persistent nerve impairments, infection, and scar formation. This article is based on a retrospective analysis of complications of bicortical screw fixation observed in 241 consecutive patients with dento-skeletal Class III, corresponding to 482 sides, during the immediate postoperative period and at 1, 3, 6, and 12 months' follow-up. In the immediate postoperative period, poor stability of fixation caused by screw loosening was observed in 3 of 482 (0.62%) sides; at the 1-month follow-up, infections were encountered in 12 (2.48%) sides at mandibular angles. Additional complications were not seen in the series. Stability of fixation was found in the 482 sides at 12 months. However, complications directly related to bicortical screws were observed in 15 sides or 3.11%. Age and gender of patients were not correlated with the incidence of complications. Assiduous follow-up during the early postoperative period and 1 and 2 months after surgery is recommended in patients with bicortical screw fixation after BSSO to verify adequate oral hygiene and provide early observation of the onset of any infections, skeletal instabilities, or relapses.

Frey's syndrome after condylar fracture: case report

Frey's syndrome is the occurrence of hyperesthesia, flushing and warmth or sweating over the distribution of the auriculotemporal nerve and/or greater auricular nerve while eating foods that produce a strong salivary stimulus. Frey's syndrome is also known as auriculotemporal syndrome and gustatory sweating. We present a case of Frey's syndrome after a condylar fracture and its treatment by internal rigid fixation. A review of the literature is provided along with mention of a simple test (Minor's test) that can help in the diagnosis of this syndrome.

[Implant prosthesis rehabilitation after maxillofacial injuries--case report]

The dental and oral rehabilitation of patients with severe trauma that involves the oral cavity is demanding and challenging. Recently, advanced surgical techniques and innovations in oral implantology led to more sophisticated treatment modalities that may better fulfill the patients needs in special situations. Young people rather often suffer from accidents--at school and during leisure activities--in a period of their life that has a great impact on their physical, mental and personal development. Thus, the wish for a quick functional and esthetical rehabilitation contrasts with the complex clinical situation and the compromised oral conditions. All persons involved in the rehabilitation process--including the patient--must seek for the best solution that takes into account treatment time, invasivity of procedures and patients morbidity. Further, it is also observed that insurances very much stress the reduction of cost and the simplicity of treatment. This will also influence the treatment planning and the sequence of the procedures as shown by the following case.

[Results of an evaluation of clinical practice in orthognathic surgery in France in 2002]

BACKGROUND

Over the years, orthognathic surgery has become a mainstay of maxillofacial surgery and is the object of many publications and oral communications. However, in spite of well-established methodology, disparities still exist in France basically concerning the way orthognathic surgery is performed.

MATERIALS AND METHODS

In relation with the XXXIXth congress of Stomatology and Maxillofacial surgery, a questionnaire was mailed to 100 French maxillofacial surgeons. Questions dealing with some practical points of orthognathic surgery (condylar positioning, osteosynthesis technique, rate of condylar resorption.) were asked.

RESULTS

Overall reply rate was 37%. Condylar positioning was performed empirically in 73% of the cases. Mandibular osteosynthesis was achieved by titanium miniplates alone in 70%. Post-operative condylar resorption rate was about 2%. This survey produced numerous astute comments.

DISCUSSION

This survey highlighted the interest of maxillofacial surgeons for practical aspects of orthognathic surgery including the questions of condylar positioning or osteosynthesis technique. These points are instrumental in achieving high-quality surgical result.

Proximal segment positioning in bilateral sagittal split osteotomy: intraoperative controlled positioning by a positioning splint

PURPOSE

Most techniques of proximal segment positioning hinder intraoperative condyle displacement. However, merely maintaining condylar position cannot optimize the preoperative condyle-disc-fossa relationship. This study attempts to optimize condylar position in the osteotomy patient.

PATIENTS AND METHODS

A study group of 23 bimaxillary operated patients had intraoperative joint positioning by positioning splint and plates (9 Angle Class II, 14 Class III). After assessing the habitual and appraising the optimized condyle position on preoperative sonograms and magnetic resonance images, positioning splints were constructed as acrylic occlusal wafers in a semi-individual articulator. Set in occlusion before adaptation of positioning plates, they were intended to move the condyles into the calculated position. Eighteen bimaxillary operated control patients had conventional plate positioning according to the habitual occlusion (9 Angle Class II, 9 Class III). Clinical follow-up, axiography, or sonography was maintained for 24 months. Preoperative lateral cephalograms were scrutinized for horizontal and vertical joint spaces and compared with the immediate postoperative radiography.

RESULTS

Postoperative Class II study group patients had less dorsal and more vertical joint space and Class III patients more dorsal and vertical space compared with the controls. The study group exhibited significantly less postoperative dysfunction compared with the control group (2-way analysis of variance: P <.021, F = 9.2, alpha =.05 significance level), disc dislocation prevalence was lower (P <.07, F = 9.2), postoperative changes in condylar translation were smaller (P <.014, F = 4.9), and 8% skeletal relapses versus 22% in the controls were seen.

CONCLUSIONS

A proximal segment-positioning splint effectively positioned the condyle in the desired direction, but with considerable relapse, significantly reduced postoperative dysfunction, disc dislocations, changes to the condylar translation, and incidence of skeletal relapse at 24-month follow-up.

Vertical alveolar distraction osteogenesis with complications in a reconstructed mandible

We report here a case of vertical alveolar distraction osteogenesis with many complications that required further surgical interventions. A 54-year-old man underwent mandibular resection followed by iliac bone grafting as the result of large mandibular odontogenic keratocyst. Eleven months later, alveolar vertical distraction osteogenesis was applied to the patient for prosthetic rehabilitation. Fracture of the basal bone occurred in the consolidation period, and the fracture was fixed by the titanium miniplate system. Radiographic examination after completion of distraction osteogenesis confirmed a radiolucent area in half of the distracted area between the basal bone and the transport segment, and when the distractor was removed the radiolucent area was filled with fibrous granulation tissue. The granulation tissue was removed and endosteal implants were inserted together with a bone graft. Ultimately, all implants were osseointegrated, and adequate esthetics and function of the implant-supported prosthesis were achieved.

Maxillary distraction using a trans-sinusal distractor: technical note

In this pilot study, the principle of distraction osteogenesis was used to advance the midface of a boxer dog. A modified high Le Fort I-type osteotomy was performed. Following a latency period of 5 days the maxilla was distracted 14 mm in 14 consecutive days at a rate of 1 mm per day. Ten weeks after the completion of the distraction, multiple biopsies were taken across the distraction gap. Histological observation showed bone deposition in the osteotomy sites. Soft and hard tissue formation resulted in complete healing across the distraction gap. The maxillary sinus was used to accommodate the distraction device. Superimposition of the standardized lateral cephalograms taken at the end of distraction and 14 months after the removal of the distractors showed no sign of relapse in the achieved sagittal advancement of the maxilla. This small, intraoral trans-sinusal placed distractor has a completely new conceptual design, and may be helpful in distraction of maxilla in children and adults with midfacial hypoplasia.

Reconstruction of maxillectomy defect by transport distraction osteogenesis

The study aimed to explore the feasibility of posterior maxillectomy reconstruction by transport distraction in a primate model. In each of 14 male adult rhesus monkeys, posterior partial maxillectomy was performed on one side of maxilla to create a posterior maxillary deflect. Immediately after the maxillectomy, a dentoalveolar segment anterior to the defect was osteotomized as transport segment and a custom-made transport distractor was fixed on the residual maxilla. After a latency period of 5 days, the distractor was activated 1 mm daily to move the transport segment backward to the defect. This process lasted about 2 weeks. The transport segment was allowed to consolidate and the animals were sacrificed at different defined intervals. Transport distraction was successful in six animals. Three other cases were completed with minor wound dehiscence and one had a small oro-antral fistula with subsequent maxillary sinusitis. New bone bridging the distraction gap was confirmed by radiography and histology in the animals completing distraction. Reconstruction of posterior maxillectomy defect is proven feasible by transport distraction osteogenesis.

Can monocortical miniplates provide bony compression? An experimental model

Some maxillofacial surgeons advocate that screws in monocortical plate systems be placed eccentrically in an attempt to provide compression between bony ends. We sought to quantify the degree of displacement and compressive forces made possible by such eccentric placement in an experimental model using five miniplates and Perspex blocks to simulate mandibular fractures. The maximum displacement obtained was 0.67 mm and the maximal compressive force 5.2N (SEM=0.9, range=2.7-7.1). This demonstrates that eccentric placement of screws can achieve some compression and displacement at the fracture interface and that the forces obtained are close to those predictable from the dimensions of the burr, screw, and miniplate.

Spontaneous mandibular fracture in a partially edentulous patient: case report

This article describes the case of a 78-year-old patient whose mandibular fracture was treated with miniplate osteosynthesis. After initial treatment, panoramic radiography revealed a fracture of the miniplate, and at follow-up, a loosening of the replacement plate. For the dental practitioner, this clinical case highlights the importance of panoramic radiography and occlusal analysis and stabilization for diagnosis of mandibular fracture, evaluation of miniplate fracture and treatment, especially in the absence of trauma.

Comparative assessment of two methods used for interdental immobilization

AIM

This investigation was carried out to compare Dimac wires with arch bars for interdental immobilization.

MATERIAL AND METHODS

The assessment was conducted on 50 patients who had mandibular fractures and in whom intermaxillary fixation was required as a part of the treatment. The time required for applying each method of fixation, the needle-stick injuries that occurred during their application, and the periodontal damage that followed interdental immobilization was investigated.

RESULTS

The mean time required for the application of Dimac wires was significantly less than that required for arch bars. The needle-stick injuries were significantly less with Dimac wires. Patients reported difficulty with oral hygiene with arch bars in place. This was associated with periodontal damage following removal of fixation.

CONCLUSION

Dimac wires is safer to use and less traumatic to the periodontium

Infections associated with locking reconstruction plates: a retrospective review

PURPOSE

In this study, we examined the incidence of infection with the use of a locking reconstruction bone plate/system.

PATIENTS AND METHODS

All patients, treated with a locking reconstruction bone plate/screw system for mandible fractures in the Oral and Maxillofacial Surgery service over a 28-month period at a level I trauma center, were evaluated through a retrospective chart review by independent examiners. The use of a locking reconstruction plate was determined by the attending staff involved in the patient's care. Patient population included single, bilateral, and comminuted fractures. Patient characteristics were noted and include dentate versus edentulous, smoking history, and history of previous infection.

RESULTS

Fifty-six locking bone plates were placed in 42 patients. Eight (19%) of the patients were infected before treatment. A persistent infection remained in 3 of these 8 patients (37.5%). Two patients (5.8%), with 3 fracture sites (6.4%) developed postoperative infection that required further intervention. All 5 of the patients who were infected after surgery were heavy smokers. History of preoperative infection and smoking appear to be significant factors in the etiology of postoperative infection. All postoperative infections resolved successfully with local measures and with no loss of fixation.

CONCLUSION

The use of locking reconstruction plates can facilitate the management of complicated fractures; however, it does not eliminate complications. Postoperative infections are related to numerous factors, including preoperative incidence of infection, smoking, and proper use of the plates.

Treatment of severe mandibular fractures using AO reconstruction plates

PURPOSE

The goal of this study was to retrospectively evaluate the use of 2.4-mm AO titanium reconstruction plates for mandibular fractures.

PATIENTS AND METHODS

We analyzed the clinical and radiologic data of 63 patients with 63 single fractures (53 comminuted, 5 dislocated, and 5 with bone loss) and 2 patients with double fractures. Fracture location was symphysis in 37 patients (56.9%), body in 13 (20%), and angle in 15 (23.1%). We recorded the mechanism of injury, time between injury and surgery, gender and age, temporary maxillomandibular fixation (MMF) and its duration, and surgical approach. Follow-up examinations were performed at 1, 3, 6, and 12 months, at which time we noted the status of healing and any complications.

RESULTS

Fifty patients (77%) had a successful treatment outcome without complications; 13 patients (20%) developed minor complications; and 2 patients (3%) developed nonunion with infection requiring hardware removal and reosteosynthesis with bone graft.

CONCLUSIONS

We found that 2.4-mm AO titanium reconstruction plates can be used to treat severe mandibular fractures with a low rate of major complications (3%) and a high success rate.

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

PURPOSE

Our goal was to study the use of 2.0-mm miniplates for the fixation of mandibular fractures.

PATIENTS AND METHODS

Records of 191 patients who experienced a total of 280 mandibular fractures that were treated with 2.0-mm miniplates were reviewed. One hundred twelve of those patients, presenting 160 fractures, who attended a late follow-up were also clinically evaluated. Miniplates were used in the same positions described by AO/ASIF. No intermaxillary fixation was used. All patients included had a minimum follow-up of 6 months. Demographic data, procedures, postoperative results, and complications were analyzed.

RESULTS

Mandibular fractures occurred mainly in males (mean age, 30.3 years). Mean follow-up was 21.92 months. The main etiology was motor vehicle accident. The most common fracture was the angle fracture (28.21%). Twenty-two fractures developed infection, for an overall incidence of 7.85%. When only angle fractures are considered, that incidence is increased to 18.98%. Although only 1 patient (0.89%) described inferior alveolar nerve paresthesia, objective testing revealed sensitivity alterations in 31.52% of the patients who had fractures in regions related to the inferior alveolar nerve. Temporary mild deficit of the marginal mandibular branch was observed in 2.56% of the extraoral approaches performed and 2.48% presented with hypertrophic scars. Incidence of occlusal alterations was 4.0%. Facial asymmetry was observed in 2.67% of the patients, whereas malunion incidence was 1.78%. Fibrous union, mostly partial, occurred in 2.38% of the fractures, but only 1 of those presented with mobility (0.59%). Condylar resorption developed in 6.25% of the fixated condylar fractures. Mean mouth opening was 42.08 mm.

CONCLUSION

The overall incidence of complications, including infections, was similar to those described for more rigid methods of fixation.

Computerized analysis of resorbable polymer plates and screws for the rigid fixation of mandibular angle fractures

PURPOSE

This computer-based study used finite element analysis (FEA) to assess whether rigid fixation by resorbable polymer plates and screws can provide the required stiffness and strength for a typical mandibular angle fracture.

MATERIALS AND METHODS

Two separate 3-dimensional FEA models of the mandible were generated using 8-noded hexahedral elements. The jaw segments in 1 model were fixed with titanium plates and screws as those in common use today. The jaw segments in the other model were fixed with resorbable polymer plates and screws as used in a developmental product currently in trials. A commercial finite element solver was then applied to this mesh to compute stresses and bone interfragmentary displacements for both titanium fixation and resorbable fixation. Calculated displacements were compared with each other and to established norms for healthy bone regrowth. Calculated stresses were compared with the yield strength of each material. Finally, overall stress patterns in the fractured mandibles were compared with each other.

RESULTS

The study results indicate that titanium fixation more rigidly fixes the 2 bone segments in relative position. However, they also show that resorbable polymers provide sufficient stiffness to meet currently established norms for fracture immobility. Furthermore, the analyses show that resorbable polymers are capable of withstanding the stresses generated by the bite loads of postsurgical patients. The results indicate that mandibles, fixed with either titanium or resorbable materials, show nearly identical stress patterns.

CONCLUSIONS

The resorbable polymer-based plates and screws tested in this investigation are of adequate strength and stiffness for their successful application to the rigid fixation of mandibular angle fractures.