Experimental study on fractures of the mandibular condylar process (mandibular condylar process fractures)

Superior Dislocation of the Mandibular Condyle into the Middle Cranial Fossa: A Comprehensive Review of the Literature

The superior dislocation of the condyle into the cranium occasionally requires invasive procedures due to the absence of a timely diagnosis. This review analyzed the available clinical data to provide information on treatment decisions. The reports were assessed using electronic medical databases from inception to 31 October 2022. A total of 116 cases from 104 studies were assessed; among the patients, 60% and 87.5% of the affected women and men required open reduction, respectively. The ratio of closed to open procedures within 7 days after injury was maintained; however, closed reduction decreased over time, and all cases required open reduction after 22 days. Eighty percent of the patients with a total intrusion of the condyle required open reduction, whereas the frequency for both procedures was comparable in the remaining patients. Open reduction was significantly more frequently performed for men (p = 0.026, odds ratio; 4.959, 95% confidence interval; 1.208-20.365) and less frequently performed in cases with partial intrusion (p = 0.011; odds ratio: 0.186; 95% confidence interval: 0.051-0.684); the frequency varied according to the time until treatment (p = 0.027, odds ratio; 1.124, 95% confidence interval; 1.013-1.246). Appropriate diagnostic imaging and prompt diagnosis are indispensable for minimally invasive treatment of this condition.

Comparison between Glenoid Fossa Roof Thickness in TMD and non-TMD Patients, a CBCT Study

Statement of the Problem

Various pathologic conditions can affect the thickness of the roof of glenoid fossa (RGF). The relationship between the RGF thickness and temporomandibular joint disorder (TMD) is not explicitly investigated. Considering the changes in RGF thickness, as a radiographic sign for TMD diagnosis, the phenomenon may necessitate specific treatment and may influence the treatment course and results.

Purpose

This research was designed to examine the relationship between TMD and RGF thickness changes compared to non-TMD group.

Materials and Method

In this cross sectional analytic research CBCT images of 70 TMD patients (140 joints) and 70 non-TMD individuals (140 joints) as control group were evaluated for thickness of RGF and presence of discontinuity in RGF. The distance between superior and inferior cortex of glenoid fossa was measured as RGF thickness. Inability to follow the course of cortex in any given image was considered as discontinuity. T-test, Chi-square and odds ratio (OR) were used for statistical analysis. In this study, p< 0.05 was considered meaningful.

Results

The mean thickness of RGF in our non-TMD samples was 1.12 mm. RGF thickness was significantly increased in TMD patients compared non-TMD group (p= 0.00). This value was also greater in males. On the other hand, TMD patient showed a higher incidence of discontinuity in RGF, in comparison with non-TMD patients (p= 0.006).

Conclusion

The increased thickness of RGF can be considered as a sign of TMD, which may help in diagnosis of TMD. It seems that there is a direct relationship between TMD and discontinuity of RGF.

Anatomical Examination of Mandibular Condyle Protrusion Into the Middle Cranial Fossa

Trauma to the mandible can occasionally be a life-threatening event. Although extremely rare with only 56 reported patients in the English language, fracture of the floor of the middle cranial fossa with protrusion of the mandibular condyle into the middle cranial fossa was first reported in 1963 by Dingman. The authors review the anatomy of the temporomandibular joint in relation to the middle cranial fossa and demonstrate the possible complications due to condylar intrusion with anatomical dissection.

A Case of Glenoid Fossa Fracture, Progressive Ankylosis, Total Joint Reconstruction with Alloplastic Prosthesis to Normalized Function Including Evaluation with F18-PET/CT-a Four Year Follow-up

Temporomandibular joint replacement (TJR) with alloplastic prosthesis has shown promising long-term results in end stage joint disorders. We present a case of young woman with painful ankylosis that where reconstructed with TJR, due to a complex mandibular fracture with dislocation of the left condyle into the middle cranial fossa two years earlier. At the age of 18 the subject underwent a total joint replacement with custom-made alloplastic TMJ prosthesis. To determine the bone response and remodeling activity around the prosthesis, a F18 PET/CT-scan was used. No sign of increased remodeling or pathology were seen in the imaging after the reconstruction. Four years postoperatively the subject reports no pain and excellent jaw function.

Mechanics in the Production of Mandibular Fractures: A Clinical, Retrospective Case-Control Study

As the mandible is susceptible to fracture, the aim of this study was to use multivariate logistic regression analysis to identify and distinguish various internal factors that may influence the location of mandibular fractures. The study included 1131 patients with maxillofacial fractures during the period from January 2000 to December 2009 to evaluate the association of mandibular fracture location (unilateral symphysis, body, angle, condylar, or bilateral condylar fractures) with various internal factors. Among the 1131 patients, 869 had mandibular fractures. Data on age, sex, soft tissue injuries, dental trauma, and maxillofacial fracture type were collected and analyzed using multivariate logistic regression. In total, 387, 210, 139, 319, and 172 patients were diagnosed with unilateral symphysis, body, angle, unilateral, or bilateral condylar fractures, respectively. The dental trauma in patients with bilateral condylar fractures differed from that in patients with unilateral condylar fractures. Patients with mandibular fracture (unilateral symphysis, body, unilateral or bilateral condylar) possessed an approximately equal risk of soft tissue injuries in the mandible. Patients with either unilateral or bilateral condylar fractures were associated with a low risk of mandibular angle fracture (OR < 1). Similarly, patients with mandibular angle fracture were associated with a low risk of unilateral or bilateral condylar fractures (OR < 1). Moreover, patients with symphysis fracture were associated with a low risk of bilateral condylar fractures (90 of 387 [23.3%], OR 0.899). By contrast, patients with bilateral condylar fractures were associated with a high risk of symphysis fracture (90 of 172 [52.3%], OR 17.38). Patients with condylar fractures, particularly those with bilateral condylar fractures, were infrequently associated with secondary mandibular fractures. Mandibular fractures tended to have less of an association with midfacial fractures. The occurrence of mandibular fractures is strongly correlated with age, sex, soft tissue injuries, dental trauma, and the pattern and position of the maxillofacial fractures in patients.

A follow-up study on extracorporeal fixation of condylar fractures using vertical ramus osteotomy

Objectives

The aim of this study is to report the results of extracorporeal fixation in patients with mandibular condylar fractures and compare them with the clinical results of conservative treatment.

Materials and Methods

The medical records of 92 patients (73 male [M] : 19 female [F], age 13-69 years, mean 33.1 years) treated for condylar fractures at the Department of Oral and Maxillofacial Surgery in Sun Dental Hospital (Daejeon, Korea) from 2007 to 2012 were reviewed. Patients were divided into three groups: group A (23 patients; M : F=18 : 5, age 21-69 years, mean 32.6 years), treated with extracorporeal fixation; group B (30 patients; M : F=24 : 6, age 16-57 years, mean 21.1 years), treated by conventional open reduction; and group C (39 patients; M : F=31 : 8, age 16-63 years, mean 34.4 years), treated with the conservative method ('closed' reduction). Clinical and radiographic findings were evaluated and analyzed statistically.

Results

Occurrence of postoperative condylar resorption correlated with certain locations and types of fracture. In this study, patients in group A (treated with extracorporeal fixation) did not demonstrate significant postoperative complications such as malocclusion, mandibular hypomobility, temporomandibular disorder, or complete resorption of condyle fragments.

Conclusion

In superiorly located mandibular condyle fractures, exact reconstruction of condylar structure with the conventional open reduction technique can be difficult due to the limited surgical and visual fields. In such cases, extracorporeal fixation of the condyle using vertical ramus osteotomy may be a better choice of treatment because it results in anatomically accurate reconstruction and low risk of complications.

Traumatic dislocation of intact mandibular condyle into middle cranial fossa

INTRODUCTION

A 10-year-old girl presented to the Emergency Department with temporomandibular joint pain, malocclusion, and trismus after a bicycle accident.

METHODS

CT of the temporal bones showed displacement of the right mandibular condyle into the middle cranial fossa with small intraparenchymal hemorrhage. The condyle was reduced using closed reduction technique and the patient was placed in maxillomandibular fixation.

RESULTS

Complete reduction of the displaced condyle with resultant normal occlusion and persistent bony defect in the temporal bone.

CONCLUSION

In early follow-up assessments the patient has had complete resolution of symptoms with residual bony defect from the site of fracture in the temporal bone.

Dislocation of a fractured mandibular condyle into the middle cranial fossa: a case treated by an extracranial approach

INTRODUCTION

Penetration of the mandibular condyle into the middle cranial fossa is a rare complication usually due to blunt traumas to the chin. Particular anatomical and dynamic conditions can lead to the intracranial dislocation of the condyle in spite of the fracture of the condylar neck that usually prevents this event from dissipating the kinetic force of the impact.

DISCUSSION

We report the case of a 10-year-old female patient suffering from symphyseal and bilateral condilar fracture with intrusion of the left condyle into the middle cranial fossa. The diagnosis of intracranial dislocation was initially missed because of the nonspecific symptomatology and insufficient radiologic data provided by conventional investigations (plain X-rays and panoramic views). The persistence of the limitation of the mouth opening and the worsening of the preauricular pain with irradiation to the temporal region led us to perform further radiological investigations (computed tomography scan and magnetic resonance imaging) that revealed the intracranial complication. A successful removal of the displaced condyle was carried out through an extracranial approach, and at a 3-year follow-up temporomandibular joint function is satisfactory.

CONCLUSION

The case is reported to emphasize the need for careful radiological investigation in case of condylar fractures and the effectiveness of the extracranial route to surgically treat these rare complications.

Dislocation of the mandible into the middle cranial fossa. Case report

Dislocation of the mandibular condyle into the middle cranial fossa is a rare event due to anatomical and biomechanical factors. The authors report the case of a 12-year-old girl who presented with this condition after colliding with a classmate. One day after her injury, the patient demonstrated an inability to close her mouth completely, and she had minor tenderness to palpation anterior to the tragus, without neurological deficits. Imaging studies demonstrated a fractured glenoid fossa with intrusion of the mandible into the cranial cavity. Open reduction of the mandibular condyle was performed, and the glenoid fossa was reconstructed with a split-thickness bone graft and titanium screws. Several dural tears noted at the time of surgery were repaired primarily. Mandibular condyle dislocation into the middle cranial fossa is often misdiagnosed initially because of its low incidence and nonspecific symptoms. Computed tomography scanning is the most sensitive diagnostic study for detecting this injury. Closed reduction after induction of general anesthesia has been recommended in recently suffered injuries without neurological deficits, but this approach may overlook damage to intracranial structures. Surgical repair is recommended if neurological injury is suspected. Treatment options should be tailored to the individual factors of each case.

Ballistic Impact to the Forehead, Zygoma, and Mandible: Comparison of Human and Frangible Dummy Face Biomechanics

BACKGROUND

Currently, there is a greater use of nonlethal force in law enforcement and military operations. Because facial injuries have been observed, there is a need to understand the human response to ballistic impacts involving various regions of the face. This study aimed to establish blunt ballistic response corridors for high-speed, low-mass facial impacts to the forehead, zygoma, and mandible, and to determine how these responses compare with those of the frangible Hybrid III headform. Correlation of the human and dummy responses allows injury risk assessment for munitions used in the field.

METHODS

Facial impacts to the forehead, zygoma, and mandible of six cadavers at 42 +/- 10 m/sec were conducted using a 25- to 35-g projectile 37 mm in diameter that was instrumented with an accelerometer to determine impact force. High-speed video analysis determined penetration of the projectile, and autopsy determined the facial fractures. Force and deflection were normalized for the 50% tile response, and corridors were determined for blunt ballistic impacts. Similar tests were conducted on the frangible face of the Hybrid III dummy.

RESULTS

Peak normalized force of 3.5 +/- 0.9 kN on the forehead and 3.0 +/- 1.0 kN on the mandible did not result in fractures, whereas an impact force of 2.3 +/- 0.5 kN on the zygoma caused anterior maxilla fractures. The frangible Hybrid III face developed similar force levels, but with less penetration of the projectile. Its stiffness was 43% greater than that of the cadaver.

CONCLUSIONS

Higher impact force can be tolerated on the forehead and mandible than on the zygoma. Normalized force-deflection and force-time corridors were established for the human response. The frangible Hybrid III face is an effective surrogate for assessing ballistic injury risks, but greater compliance would make it more biofidelic. Initial human tolerance levels of 6.0 kN for the forehead, 1.6 kN for the zygoma, and 1.9 kN for the mandible have been established for ballistic impacts to the face.

Deformation characteristics of the human mandible in low impact experiments

A total of 11 human mandibles were subjected to physical impacts under standardised conditions. Two impact sites and directions were tested and the impact load was varied in four steps. Two occlusional strengths were applied and the influence of simulated soft tissue covering was recorded. The deformation of the bones was measured using strain gauge strips located at eight defined sites. In a series of frontal to occipital impacts the frontal areas and the collum showed the largest length changes. Increasing impact intensities led to a proportional increase of the length changes. An increase of the occlusional strength was either protective (at the collum) or it increased the deformation (frontal area). The soft tissue covering was only partly protective. Lateral impact was characterised by a compression on the side of the impact and stretching on the other side only. The intensity and speed of deformation increased with increasing distance from the site of impact. A fixed occlusion caused an increase of compression at the site of impact and an increasing stretching in the frontal part of the bone and at the opposite collum.

Fracture of glenoid fossa and traumatic dislocation of mandibular condyle into middle cranial fossa

Traumatic mandibular condyle dislocations into the middle cranial fossa are rare. Thirty-three cases of middle cranial fossa injuries caused by condylar dislocations have been reported in the literature. A case report of a patient with a traumatic dislocated condyle into the middle cranial fossa, which was treated conservatively, is presented.

Intracranial dislocation of the mandibular condyle: report of two cases and review of the literature

Fractures of the mandibular condylar process are common and account for up to 40% of all mandibular fractures. Penetration of the condylar head into the middle cranial fossa is, however, rare. We have found reports of only 43 cases since 1834. The diagnosis of intracranial condylar dislocation is difficult, there are usually no particular symptoms or neurological signs. As a result, detailed radiological studies are necessary. In the absence of clear radiographic images of the condylar structures, computed tomography (CT) is essential to locate the fragments and to investigate and monitor intracranial lesions. This paper describes the diagnostic and surgical procedures used in two cases of condylar dislocation and discusses them with reference to previous cases. The use of a titanium screw, which was positioned intracranially in the first case, has not, to our knowledge, been described previously.

Cranial dislocation of the mandibular condyle. A case report with an unusual hearing loss

The case of a 37-year-old woman who suffered a condylar dislocation into the middle cranial fossa is reported. The mechanisms of injury, the problems of clinical diagnosis and the management are discussed.

The effect of indirect trauma on the rat temporomandibular joint

The effect of indirect trauma to the rat temporomandibular joint (TMJ) is analysed by means of an experimental model. The trauma, applied from an angle-glenoid fossa direction, produced injury of the TMJ. The histological data demonstrated that the impact could produce fractures of the glenoid fossa, but no hemarthrosis was observed. Trauma, both with or without fracture, caused proliferative changes in the TMJ. The glenoid fossa, the articular disk and the articular surface of the condyle were injured. Thickening of the articular surfaces had resulted in reduced joint space. Subsequently, remodelling changes in the condyle were found.