Dysgnathia, orthognathic surgery and spinal posture.

The aim of this study was to evaluate the spine by video rasterstereography before and after orthognathic surgery. Twenty-nine patients (17 patients with a skeletal class III, 7 patients with a skeletal class II, and 5 patients with mandibular asymmetry) were evaluated preoperatively and 1 year postoperatively. Video rasterstereography is a method of back surface measurement and shape analysis using the moire topography. Orthognathic surgery in cases of class III and asymmetry did not lead to significant changes in body posture. In class II patients it led to some changes in body posture, but without orthopaedic consequences. It is concluded that orthognathic surgery causes minimal or no change in body posture.

Arthroscopic laser surgery in temporomandibular functional joint disorders.

AIM: The authors present the 1-year results of combined use of arthroscopic lysis and lavage procedure, capsular stretch and holmium:yttrium-aluminium-garnet (Ho:YAG) laser techniques for the treatment of chronic closed lock of the temporomandibular joint. METHODS: Twelve joints were treated in 10 patients (9 females and 1 male) affected by anterior disk displacement without reduction not responsive to conservative treatment. All the patients were studied with preoperative magnetic resonance immaging (MRI). Surgical procedures included lysis and lavage, capsular stretch and Ho:YAG laser techniques with anterior release, posterior scarification and debridment of cartilage surface. The individual outcome was evaluated with the clinical examination, a visual analogue scale (VAS) for pain and a questionnaire concerning mandibular functional impairment. Patients were followed-up for 1 year. RESULTS: One-year results show that 9 patients (success rate 90%) achieved improvement of mandibular function and reduction of pain. The clinical recordings at the 1-year follow-up indicated good outcomes. Nine patients could masticate a regular diet at 1-year follow-up. CONCLUSIONS: These findings seem to justify the use of Ho:YAG laser techniques together with the lysis and lavage procedure and capsular stretch for the treatment of chronic closed lock of the temporomandibular joint. These arthroscopic procedures represent the first choice and an effective approach in the surgical treatment of this condition.

Basic research and 12 years of clinical experience in computer-assisted navigation technology: a review.

Computer-aided surgical navigation technology is commonly used in craniomaxillofacial surgery. It offers substantial improvement regarding esthetic and functional aspects in a range of surgical procedures. Based on augmented reality principles, where the real operative site is merged with computer generated graphic information, computer-aided navigation systems were employed, among other procedures, in dental implantology, arthroscopy of the temporomandibular joint, osteotomies, distraction osteogenesis, image guided biopsies and removals of foreign bodies. The decision to perform a procedure with or without computer-aided intraoperative navigation depends on the expected benefit to the procedure as well as on the technical expenditure necessary to achieve that goal. This paper comprises the experience gained in 12 years of research, development and routine clinical application. One hundred and fifty-eight operations with successful application of surgical navigation technology--divided into five groups--are evaluated regarding the criteria "medical benefit" and "technical expenditure" necessary to perform these procedures. Our results indicate that the medical benefit is likely to outweight the expenditure of technology with few exceptions (calvaria transplant, resection of the temporal bone, reconstruction of the orbital floor). Especially in dental implantology, specialized software reduces time and additional costs necessary to plan and perform procedures with computer-aided surgical navigation.

MRI-based stereolithographic models of the temporomandibular joint: technical innovation.

A new technique of manufacturing dual-colour stereolithographic models of hard and soft tissues of the temporomandibular joint (TMJ) is presented. Sagittal T1/PD weighted magnetic resonance (MR) images of joints with and without disc displacement were obtained in the closed and open mouth positions. Individual interactive contour identification of bony structures and the articular disc followed by binary interpolation provided the data for the generation of acrylic TMJ models. Three dimensional in vivo visualization of the articular disc in relation to bony structures in the closed and open mouth positions allows a new perception of normal and pathological TMJ anatomy.

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.

Colour stereolithography for planning complex maxillofacial tumour surgery.

High-precision anatomical facsimile models of the patients' skulls, individually produced by colour stereolithography, were used in the preoperative planning for seven patients with complex maxillofacial tumours. Selectively coloured models facilitated the management of ablative surgery and reconstructive procedures as well. The indicators for preoperative colour stereolithographic model planning concerning maxillofacial tumour surgery are discussed.

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.

Functional reconstruction in a case of osteoblastoma of the mandibular condyle.

Resection of the mandibular condyle inevitably leads to functional impairment even in cases of reconstruction with prosthesis or autogenous bone graft. Loss of function is caused by the loss of action of the lateral pterygoid muscle. Therefore, preservation and fixation of this muscle to a transplant should be performed whenever possible. A case of osteoblastoma of the condylar head and neck with functional reconstruction after ablative surgery is presented.

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.

The platysma myocutaneous visor flap for intraoral reconstruction. A case report.

The use of a modified myocutaneous platysma flap is presented for a patient with a large ameloblastoma of the mandible. The possible advantages and limitations of the technique are discussed.

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.

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.

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.

Reperfusion of autotransplanted teeth--comparison of clinical measurements by means of dental magnetic resonance imaging.

OBJECTIVE: Dental magnetic resonance imaging (dMRI) with administration of contrast material is one method of assessing pulpal perfusion. The purpose of this study was to evaluate the level of contrast enhancement displayed by means of dMRI after transplantation of teeth and to compare these findings with the results of tooth mobility, pocket depth, cold, and electrical tests. STUDY DESIGN: Twenty-three teeth with either complete root formation or incomplete root formation (IRF) were investigated by using dMRI and were clinically examined at intervals of 2, 4, 8, and 12 weeks, as well as 6 months and 12 months after transplantation. RESULTS: An analysis of the enhancement in the dental images revealed a significant difference between teeth with IRF and teeth with complete root formation. In addition, the time to occurrence of a positive reaction to the cold test was significantly longer for teeth with IRF. CONCLUSIONS: The findings of this study indicate that transplanted IRF teeth are associated with reperfusion seen by means of dMRI as well as with delayed occurrence of a positive cold test.

Is failure of condylar neck osteosynthesis predictable based on orthopantomography?

BACKGROUND: Osteosynthesis failure rates of 11.3% with 1 miniplate, 6.7% with 2 miniplates, and 4.4% with a single Medartis condyle plate were reported in previous studies of our clinic. Current science is still focused on the osteosynthesis material. Besides clinical parameters, conventional radiographs are still the first choice to detect osteosynthesis failures. This study scrutinized several factors assessable in postoperative orthopantomographs which might elevate the risk of osteosynthesis failure. STUDY DESIGN: A total of 136 patients (22 with osteosynthesis failure, 114 without) with 151 mandibular condyle fractures were included in this study. Eight parameters were assessed in postoperative orthopantomographs. RESULTS: The best predictor of osteosynthesis failure was a simplified concept of ramus height. In cases of reduced or normal ramus height, the odds of osteosynthesis failure was significantly (P = .000001) reduced to a 10th. Isolated fractures were significantly more error prone (P = .0009). CONCLUSIONS: Postoperative orthopantomographs depict factors which increase the risk of osteosynthesis failure.

[Postoperative temporomandibular joint diagnosis]. / Postoperative Kiefergelenkdiagnostik.

Postoperative management of patients suffering from symptoms of the temporomandibular joint does not differ considerably from the one of preoperative examination protocols. Knowledge of previous surgery helps to plan patient work-up and to interpret normal postoperative findings (eminectomy, discectomy, susceptibility artefacts from metallic residues...) and typical complications (intraarticular loose bodies, dislocations, avascular necrosis, foreign body granulomatous reactions) appropriately.

Augmented reality environment for temporomandibular joint motion analysis.

The principles of interventional video tomography were applied for the real-time visualization of temporomandibular joint movements in an augmented reality environment. Anatomic structures were extracted in three dimensions from planar cephalometric radiographic images. The live-image fusion of these graphic anatomic structures with real-time position data of the mandible and the articular fossa was performed with a see-through, head-mounted display and an electromagnetic tracking system. The dynamic fusion of radiographic images of the temporomandibular joint to anatomic temporomandibular joint structures in motion created a new modality for temporomandibular joint motion analysis. The advantages of the method are its ability to accurately examine the motion of the temporomandibular joint in three dimensions without restraining the subject and its ability to simultaneously determine the relationship of the bony temporomandibular joint and supporting structures (ie, occlusion, muscle function, etc) during movement before and after treatment.