Gerhard Undt

Transoral miniplate osteosynthesis of condylar neck fractures

OBJECTIVE In a retrospective study, we reviewed a series of 55 consecutive patients with 57 fractures of the condylar neck that were treated with transoral miniplate osteosynthesis. STUDY DESIGN Forty-one patients were included in a clinical follow-up study; the median length of study was 26.5 months (minimum, 7 months; maximum, 79 months). In a radiographic study, the positions of the condyle before open reduction, after open reduction, and more than 6 months postoperatively were evaluated in 3 radiographic planes. A statistical analysis was performed to determine factors that lead to secondary instability of the reduced condyle and to correlate the actual position of the condyle with clinical parameters collected in follow-up examinations. RESULTS At the time of the follow-up examination, the median measurement of the mandibular openings was 48.3 +/- 8.0 mm (minimum, 32 mm; maximum, 66 mm). A deviation of 2 mm to the operated side when opening was observed in 7 patients. The median range of laterotrusion was 10.0 mm to the fracture side and 9. 0 mm to the opposite side. In 7 patients, radiographic follow-up more than 6 months postoperatively revealed a medial tilt of the proximal fragment of 15 to 40 degrees despite a good immediate postoperative position of the condyle. This may be attributed to bone resorption in the fracture gap, together with a bending instability observed when titanium miniplates with a thickness of 0. 9 mm were used. The position of the condyle at the follow-up examination did not correlate with clinical parameters. CONCLUSIONS Transoral approach miniplate osteosynthesis of dislocated condylar neck fractures is indicated when visible scars in the head and neck region, which are encountered with other fixation techniques, must be avoided.

Surgical reduction and fixation of intracapsular condylar fractures: A follow up study

Controversies still exist about the preferred treatment of condylar head and neck fractures. Newly developed access techniques in combination with new methods to fix the fragments, lead to satisfactory results. This study deals with a refinement of surgical treatment of intracapsular fractures.

Treatment of recurrent mandibular dislocation, part II : Eminectomy

Fourteen patients underwent eminectomy for recurrent mandibular dislocation. The clinical follow-up period ranged from 7 months to 5 years. The function of the temporomandibular joint before and after eminectomy was analysed clinically and by computer-aided axiography. There was no significant decrease in the condylar path angle postoperatively, though the articular eminence had been removed up to its most medial portion. Translatory border movements showed significant limitation six months after surgery and normal range of motion in the first and second year after the operation. Postoperative hypermobility of the condyle was not observed.

Treatment of recurrent mandibular dislocation, part I: Leclerc blocking procedure

Nine patients with recurrent mandibular dislocation, who underwent the blocking procedure of Leclerc and Girard, as modified by Gosserez and Dautrey, are presented. The follow-up period range from 2.5 to 5 years. An axiographic study revealed significant postoperative limitation of translation of the condyle when opening, while maximal mouth opening as measured between the incisors, as well as translation of the condyle in protrusion and mediotrusion, showed no significant limitation. Long-term evaluation showed a high incidence of clicking and pain, not evident prior to surgery. The causes for recurrence in three cases were analysed.

Application of Rapid Prototyping for Temporomandibular Joint Reconstruction

PURPOSE To introduce the preliminary application of rapid prototyping (RP) for temporomandibular joint (TMJ) surgery. MATERIALS AND METHODS This study included 11 consecutive patients (13 joints) seeking TMJ replacement. All patients had previously undergone 3-dimensional computed tomography (CT) scanning (0.625-mm slice thickness) of the craniofacial skeleton. The data from CT scanning in DICOM (Digital Imaging and Communications in Medicine) format were input into the interactive Simplant CMF software program (Materialise Medical, Leuven, Belgium). Preoperative planning included segmentation and osteotomies. The movements of the jaw bones were simulated by use of Simplant CMF. The affected mandible was reconstructed based on the contralateral side. Then, the titanium plate was shaped on the reconstructed model before surgery. The bone graft was transplanted by the shaped titanium plate during the operation to reconstruct the TMJ. Twenty-four patients who underwent traditional surgery were used as the control group. The operative time of the 2 groups was analyzed with the SPSS software package, version 13.0 (SPSS, Chicago, IL), with the Student t test. The data from CT scanning in the experimental group before and after surgery were compared by paired t test. RESULTS All the incisions healed primarily without any complications. All patients were satisfied with the operation, because of their symmetric faces and good occlusion. Postoperative magnetic resonance imaging confirmed the position of the transplanted costochondral cartilage in the glenoid fossa. A group t test showed that the operative time was longer in the control group (mean, 7.09 hours) than that in the RP group (mean, 5.67 hours). Three parameters (condyle-incisor, condyle-mental foramen, and condyle-angle) from the postoperative CT scan were analyzed by paired t test, and there was no significant difference between the 2 sides. CONCLUSION RP technology provides an advanced method for TMJ reconstruction that can make the TMJ reconstruction more accurate and symmetric, improve the mandibles function, and consequently, enhance the reconstructive effect.

Recurrent mandibular dislocation under neuroleptic drug therapy, treated by bilateral eminectomy

Acute mandibular dislocations caused by extrapyramidal syndromes under neuroleptic therapy have often been reported in the literature. However, the success of surgical therapy for recurrent mandibular dislocation in patients under long-term neuroleptic therapy has been discussed controversially. In our opinion, modifications in drug therapy--including the administration of so-called atypical neuroleptics--should be considered before advocating surgery. If the revised therapeutic approach proves to be unsuccessful because of psychotic relapse or persistence of extrapyramidal symptoms, good operative results may be achieved by bilateral eminectomy as reported on three psychiatric patients in this paper. In order to avoid postoperative subluxation and internal derangement due to increased muscular tension under chronic neuroleptic therapy, as much bone as possible should be removed when performing eminectomy.

Temporomandibular Joint Eminectomy for Recurrent Dislocation

Since the days of Hippocrates, repositioning of the dislocated mandible has been an important topic in medicine and dentistry, and the first surgical techniques for the prevention of recurrent mandibular dislocation and for the treatment of long standing luxation were described in the late 1800s. Dislocation of the mandible is usually bilateral. The symptoms are open mouth, protruding chin, tense masticatory muscles, salivation, speech difficulties, and pain. In unilateral cases, the mandible deviates toward the opposite side from the dislocated condyle. On manual palpation, the glenoid fossa is empty, and the condylar head can be palpated anterior to the eminence. Some investigators have defined normal maximum translation of the condyle as the point at which the greatest convexity of the condyle meets the greatest convexity of the articular eminence. About 60% of normal subjects translate more anterior to that point without any symptoms. Subluxation occurs when the condyle translates anterior to its normal range, and the patient exhibits a temporary locking or sticking sensation that either abates spontaneously or can be reduced with selfmanipulation (Fig. 1). Dislocation is a more advanced hypertranslation in which the condyle locks anterior to the eminence in a position that cannot be self-reduced because the condyle is fixed in that position by muscular spasm (Fig. 2). This state requires medical assistance to relocate the condyle in its normal position. In some cases, periarticular application of local anesthetics or tranquillizer premedication is necessary before manual reduction of the mandible is possible. Recurrent mandibular dislocation is uncommon. Boering found an incidence of 1.8% in a population of 400 patients with symptomatic temporomandibular joint (TMJ) disorders. Recurrent mandibular dislocation is found more frequently in people with general joint laxity and in patients with internal derangement of the TMJ or with occlusal disturbances, such as loss of teeth and vertical height. It may be associated with neurologic diseases encountering increased muscular activity or tension as well as in patients suffering from extrapyramidal symptoms who are receiving neuroleptic therapy. Recurrent dislocation of the condyle may cause injury to the disc, the capsule, and the ligaments, leading to progressive TMJ internal derangement. Conservative treatment modalities and indications for surgery The rationale foroperativeinterventionisofteninfluencedbythedurationofthepatient’ssymptoms and theexhaustionofotherforms oftreatment.Conservativetreatmentincludesphysiotherapy,training the muscles to avoid excessive translation of the condyles, and prosthetic restoration of vertical height. Following an acute dislocation, immobilization of the jaw in the closed position for some days to some weeks has been advocated. For edentulous patients with repeated luxations, wearing their prostheses during the night has been successfully recommended. In patients with extrapyramidal motor disorders,

Management and outcome of condylar fractures in children and adolescents: A review of the literature

OBJECTIVE The aim of this study was to provide a comprehensive review of all kinds of case reports and clinical studies focusing on management and outcome of mandibular condylar fractures (CFs) in children and adolescents. STUDY DESIGN A PubMed search of the international literature was done, completed by an additional hand search based on the available references of the publications found. RESULTS In total, 73 articles were included in this review: 7 case reports and 2 retrospective clinical studies regarding surgical management, 1 publication with case reports, 1 prospective and 3 retrospective clinical studies comparing operative and conservative treatment, 20 publications with case reports, and 35 retrospective and 4 prospective clinical studies dealing with conservative management of CFs in children and adolescents. CONCLUSIONS Despite frequently encountered radiologic abnormalities, conservative management of CFs in children usually yields satisfactory to excellent clinical results. However, in adolescents the outcome is often reported to be less favorable. Good prospective randomized multicenter studies would clarify from which age on patients could probably benefit from operative treatment.

Cartilaginous exostoses of the mandible

Although cartilaginous exostosis is considered to be the most common tumor of the skeleton, it is relatively uncommon in the jaws. The pathogenesis of the lesion is unclear. Three cases are presented and the development of the tumors from embryonic cartilage is discussed.

Expression of VEGF-receptors in TMJ synovium of rabbits with experimentally induced internal derangement.

Our aim was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in the synovium of the temporomandibular joints (TMJ) of rabbits with experimentally induced internal derangement. Internal derangement was experimentally induced in 52 rabbit TMJ, and established on the right side of TMJ while the left side was used as the control. Each joint and its control was evaluated by magnetic resonance imaging (MRI) and endoscopy. The synovial tissues on both sides were harvested after one, two, three, and four weeks. The expression of VEGFRs mRNA was investigated in the experimental joint and its control using real-time polymerase chain reaction (PCR). Internal derangement was successfully confirmed in 45 of the 52 of the experimental joints (87%) on the right side by MRI and endoscopy. In the first and fourth week, the VEGFR-2 mRNA expression was higher in the experimental joints than in the controls (P=0.008 and P=0.02). Meanwhile, the VEGFR-1 mRNA expression was up-regulated in the experimental group compared with the controls during the fourth week (P=0.02). However, we found no significant differences in VEGFR-3 mRNA expression in the two groups during the first and fourth weeks. During the second and third weeks, the mRNA expression of the three receptors did not differ significantly among the groups. Our data have shown increased expression of VEGFR-1 and VEGFR-2 mRNA in the synovium of rabbit TMJ with internal derangement, which indicates that VEGFR-1 and VEGFR-2 may have important roles in the processes of internal derangement and formation of adhesions.