[Position of the German Society of Dental, Oral and Maxillary Health. Dental care for handicapped persons].
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Dental Care for Persons with Disabilities↗
Biomedical subjects
E Machtens
Publications and source records attributed to E Machtens.
Carcinosarcoma of the mandibular mucosa: the first report.
A 67-year-old man was referred with a squamous cell carcinoma of the left mandibular alveolar ridge verified elsewhere by an exploratory excision. After extensive staging and preoperative irradiation, a radical surgical attempt was performed. Histopathological examination and immunohistochemical analysis revealed the first case of a carcinosarcoma of the mandibular alveolar ridge. Clinical and histopathological features are presented, and treatment and prognosis are discussed.
Aged↗
Purulent pansinusitis, orbital cellulitis and rhinogenic intracranial complications.
Objectives: Acute pansinusitis is rarely seen in the maxillofacial surgery field, but often occurs in combination with orbital and intracranial involvement. Clinically this entity is of great importance, since it represents a severe disease with possibly disastrous consequences. Patients: Aetiology, diagnosis and therapy of acute pansinusitis and its complications were analysed in 36 patients treated surgically from 1987 to 1996. Results: Eighteen patients were aged between 3 and 21-years-old. Only eight suffered from pure pansinusitis, and three of an isolated purulent orbital infection. Of these 25 patients 20 had (pan-)sinusitis with orbital, three with intracranial, and two with both orbital and intracranial complications. Intracranial involvement included meningitis, empyema and brain abscess. Aetiology was rhinogenic in 26, odontogenic in six patients, and traumatic in two cases. Radiological work-up included conventional radiographs and CT in most cases, MRI was only used with special indications. Microbiological examination detected single or multiple species of micro-organisms with equal frequency. If multiple species were found, infection was mostly aerobic/anaerobic in combination. Conclusion: These purulent processes, frequently seen in young patients, require immediate surgical intervention and drainage with elimination of the cause of the disease if possible. Cooperation with other specialities is essential depending on the spread of the disease. In spite of the threatening acute symptoms, severe courses of disease or permanent defects should be avoidable. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.
Journal Article↗
[Pure titanium as bone substitute. Geometric and substance-specific aspects of computer-assisted fabrication and follow-up imaging].
Computer-assisted prefabricated skull implants of pure titanium as a bone replacement material have been used in 22 departments since 1994. Our experience with 104 implants includes clinical aspects (indication; tissue quality; surgical technique; patient guidance), but also geometric and material-specific parameters (acquisition, transfer, and evaluation of CT data; construction; manufacturing; cleaning; postoperative use of radiologic techniques). While the clinical aspects are responsibly defined by the respective surgeon, the geometric and material-specific parameters of individual implants have to comply with the laws on medical products. Therefore, the prospective documentation for each implant includes: helical CT acquisition parameters; geometric data of the computer-based skull model and implant; the cleaning procedure; and the individual marking. Medically specified pure titanium is processed by milling only so that neither purity nor structure is impaired. A specially developed milling technique guarantees the fabrication of all constructed elements down to fine details of 50 microns. Considering the necessary radiologic follow-up of defects after tumor surgery, all patients in our hospital undergo postoperative MRI examination, partly with preoperative documentation as an intraindividual control. Such comprehensive documentation and quality assurance is essential for techniques of prefabricated bone substitution. Hand in hand with scientific research and clinical application, these formal criteria have to be elaborated and fulfilled for the respective techniques. The successful determination of specifically adapted MRI sequences goes even one step further: spin-echo sequences minimize inhomogeneities of the magnetic field induced by the titanium implants and enable accurate postoperative documentation and diagnostics especially in the follow-up after tumor surgery.
Bone Substitutes↗
[Salivary gland diseases].
After more than 25 years of activity in the field of salivary gland surgery, especially parotid gland surgery, the following statements can be made. 1. Salivary gland diseases are extremely variable and their treatment requires vast clinical experience. 2. The judgement of salivary gland diseases requires highly competent pathologic assistance and a specialized laboratory in this respect. In the field of salivary gland pathology--like in many other specialized subdivisions in pathology--the need of a second opinion in order to increase the reliability of the original diagnosis has to be claimed once more. 3. A certain change has taken place in the diagnostic means. Modern techniques of visualization show a shift toward noninvasive sonography, but also toward computed tomography with or without contrast agents, and there is a steadily increasing shift toward magnetic resonance tomography as well. 4. The literature about salivary gland diseases and their therapy can no longer be overlooked and is unfortunately characterized by very different aspects of judgement, which in many cases hardly allow a comparative discussion of certain clinical and therapeutic questions. 5. Parotid gland surgery requires a clear concept concerning the different diseases, especially of the different oncologic entities. Surgical preparation of the facial nerve has to be mastered equally from the central and the peripheral course of the nerve.
Adolescent↗
[Mandibular involvement in chronic recurrent multifocal osteomyelitis (CRMO) in adulthood].
A 42-year-old patient was admitted to our clinic with the diagnosis of primary chronic osteomyelitis of the mandible. Since the initial manifestation, approximately 9 months earlier, the patient had undergone numerous antibiotic treatment trials. Various tissue specimens exhibited no microbial growth. Computer tomography demonstrated severe sclerotic changes with partly osteolytic areas in the complete right horizontal ramus of the mandible. Decortication was carried out and both soft and hard tissue specimens were taken. Histological assessment revealed slightly sclerotic bone with reactive periosteal bone production, as in chronic non-specific osteomyelitis. Because of progressive pain and paresthesia, a 3-phase skeletal scanning was performed before the planned resection. In addition to an intensive labeling in the right mandible, further intensive lesions were found at the first right rib, the sternum, and the vertebral column. The subsequent magnetic resonance tomography confirmed the infiltration, as seen in osteomyelitis, in all these areas. Under the assumption of chronic recurrent multifocal osteomyelitis (CRMO), an immunosuppressive therapy with diclofenac and prednisolone was started, which at first brought about complete remission. As CRMO is very rare in our specialty, it might be suspected that it is the cause of some cases of primary therapy-resistant osteomyelitis. The importance of early diagnosis must be underlined, because therapy differs fundamentally from that of the more common bacterial osteomyelitis. A bone scan is therefore of great value in the diagnostic scheme of therapy-resistant osteomyelitis.
Adult↗
[Significance of the height and width of the alveolar ridge in implantology in the edentulous maxilla. Analysis of 95 cadaver jaws and 24 consecutive patients].
Consideration of alveolar profiles and clinical experience demonstrate that the transversal dimension has been neglected in dental implantology so far. For a comprehensive evaluation of the impact of alveolar bone height and width, 95 edentulous bony maxillae with standardized, measured, and classified cross-sections were analyzed. With four types of implants (minimum length, 10 mm), 1076 insertions were simulated at 269 cross-sections and evaluated with regard to type of implant, position of cross-section, and class of atrophy. Similar evaluation was carried out in the clinical part of the study on 24 consecutive patients with edentulous maxillae. Implant insertion could only be simulated in 35% of the cadaver cross-sections, but had been expected in an additional 4.5% based on their sufficient bone height; length reductions were necessary in another 6%. These results depended largely on the class of atrophy. Anterior cross-sections offered better conditions than posterior ones. In contrast, implant insertion was impossible in all 24 patients. Height was primarily inadequate in 22 patients, and in two patients with sufficient bone height inadequate transversal dimensions were only recognised intraoperatively. These results allow a quantification of the impact of vertical and transversal maxillary alveolar bone dimensions. This impact primarily depends on bone height, but even with sufficient height, reductions of implant length often become necessary. Both for the cadaver maxillae (12% of the cross-sections with expected implant insertion) and for the patients (8%), alveolar profiles remain in which height measurement alone leads to incorrect assessment and may even result in the interruption of precisely planned surgical procedures. The complexity and expense of implant-borne rehabilitation and the consequences resulting from incorrect preoperative planning therefore generally justify extended cross-sectional diagnostic measuring.
Alveolar Process↗
One-step resection and reconstruction of the mandible using computer-aided techniques--experimental and clinical results.
In patients with advanced oral cancer, a resection of the mandible continuity is often indicated. This new method presented here uses computer-aided design and manufacturing (CAD/CAM) for preoperative fabrication of individual mandibular prostheses and their corresponding resection templates in a direct fashion without the need for additional physical models. In this experimental application, a segment of a dried mandible was resected and replaced by a titanium prosthesis prefabricated by CAD/CAM. It was the aim of this investigation to verify the processing chain and its precision, i.e., the fit of an individual implant, such as this. Although this new technique offers fascinating opportunities, possible clinical drawbacks have to be taken into account.
Bone Screws↗
Custom-made cast titanium implants produced with CAD/CAM for the reconstruction of cranium defects.
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Bone Plates↗
[Cheilognathopatalatoschisis. Diagnosis and therapy of a malformation- a classic interdisciplinary model].
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Adult↗
Reconstruction of an extreme frontal and frontobasal defect by microvascular tissue transfer and a prefabricated titanium implant.
A 30-year-old man was referred to us with an extreme frontal and frontobasal defect from a motorbike accident 12 years before. Multiple attempts at frontal and frontobasal revision and reconstruction had been performed over the years, with several episodes of meningitis. Reconstruction was planned in two steps. First, a revision of the anterior skull base with mobilization of meningeal adhesions and duraplasty, removal of infected masses of polymethylmethacrylate out of the upper ethmoid sinuses, and coverage with a deepithelialized latissimus dorsi free flap were performed. In the second step 3 months later, aesthetic forehead reconstruction was achieved with a pre-fabricated individual titanium implant. The predictable result of this two-step reconstruction was very pleasing. Safe separation of the cranial cavity from the upper airways was essential, requiring free tissue transfer in this case, and is a prerequisite for any alloplastic forehead reconstruction. Timing of the two-step procedure, including the CT data acquisition; handling of soft tissues, bone, and foreign material; and construction details of the implant demonstrate the necessary complex management of this, the most difficult case of the 88 applications of the new computer aided design and manufacturing technique thus far. Even the most elaborate computer aided preparation cannot be successful without consideration of established surgical principles.
Adult↗
[Pigmented villonodular synovitis of the temporomandibular joint with invasion of middle cranial fossa].
A 63-year-old man is presented in whom a tenosynovail giant-cell tumor destroyed the right temporomandibular joint and fossa and showed extensive intracranial growth. Because of uncharacteristic complaints, a symptomatic treatment was performed elsewhere. The lesion was finally resected under endotracheal anesthesia. After 20 months free of recurrence the patient's outcome is very satisfying. Differential diagnosis and therapy are discussed.
Diagnosis, Differential↗
Individual prostheses and resection templates for mandibular resection and reconstruction.
This new technique uses helical computed tomography data and computer-aided design and manufacturing for preoperative fabrication of individual mandibular prostheses together with corresponding resection templates. Coherent 3D geometries for computer-based models are the basis for the construction of prostheses and provide data for a computerized numerical control fabrication. Fixation plates are fabricated with the titanium prostheses. The identical data of these plates are used for the computer-aided design and manufacturing of resection templates, which guide an oscillating saw in a precisely determined resection plane. This plane again is identical with the prostheses' margins for mandibular body replacement. The use of this technique in four patients is reported on: after temporary insertion of the templates for resection and after resection, the prostheses were stabilized with the same screws in the same screw-holes where the templates had been. Resection and reconstruction were thus highly precise, safe and fast and primarily led to excellent aesthetic and functional results. Wound-healing depends on a safe soft-tissue reconstruction over these large prostheses. Coverage with flaps seems obligatory. In spite of the superior technical aspects, the clinical long-term results of this new technique were poor.
Adult↗
[Reconstruction in craniofacial contour and continuity defects with preoperatively designed individual implants].
Reconstruction of craniofacial bone defects with intraoperatively modeled prostheses restricts the choice of material and its biocompatibility and the prediction of the aesthetic result. This goes hand in hand with prolonged duration of the surgical procedure and increased stress for the patient. In contrast, modern industrial CAD/CAM systems allow prefabrication of titanium prostheses. Individual computer-based 3D models of the bony defect are generated after acquisition, transfer and evaluation of helical CT data. Based on these data, the individual shape of the prosthesis is designed using free-form surface geometry and fabricated by a numerically controlled milling machine. The conical margins of this prosthesis are designed with a precision of 0.25 mm to the borders of the defect, and the surface contours are generated harmonically to the non-affected neighboring contours with a constant thickness of 1.5 mm. Individual constructions for fixation with the dimensions of microplates are integrated in this process if screw-holes cannot be drilled in thin overlapping margins of the prosthesis. Reconstruction of 18 posttraumatic or postoperative cranial defects measuring up to 18 cm was performed using this new method. Wound-healing was uneventful in all cases, although some of the patients had been operated on several times before. The results were always predictable and constant using this highly precise technique, and duration of surgery was reduced dramatically.
Biocompatible Materials↗
[Damage to the optic nerve: an animal model].
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Animals↗
[Thermographic quantification of sensory and sympathetic nerve lesions in mandibular fractures--a prognostic criterium?].
As a rule, damage to segmental afferent nerves by trauma is accompanied with local impairment of sympathic functions. Standardized quantification of subjective items concerning the deficit of sensibility is quite problematical. Investigation by electrophysiological means yield not more than qualitative issues. In contrast, changes of sympathetic status and reaction of dependent dermatomas are quantitatively measurable by thermography. -26 patients with unilateral mandibular fractures complained of different posttraumatic or postoperative sensible impairment of the third branch of the trigeminal nerve. In the course of onto 3 years area and quality of the concerned neural defect were correlated to skin temperature that was measured by contact thermography and compared to the opposite reference region.- In all cases the early posttraumatic period showed a difference in temperature of the corresponding skin areas (delta T = 0.43 +/- 0.24 C). In 20 of 26 cases a relation between the changes of temperature concerning time and area and the sensible improvement could be seen. There was an individual time-lag between these developments. Side-comparing thermography was able to forecast improvement in 17 of 26 cases. Thus, the issued device provides statements about the amount and the course of posttraumatic loss of sensibility.
Follow-Up Studies↗
[Principles of surgical treatment of obstructive sleep apnea by interventions on the facial bones].
The clinical picture of the obstructive sleep apnea syndrome is caused by a multifactorial etiology. Therefore a lot of different conservative as well as surgical therapeutic approaches are discussed. In approximately 40% of the patients an obstruction of the pharyngeal airway is combined with an abnormal sagittal morphology of the skull. In these cases a simultaneous maxillomandibular advancement by at least 10 mm seems to be a causal therapy, leading to an enlargement of the pharyngeal airways. The current therapeutic results are roughly stable up to a period of approximately 3 years. Requirement of this therapy is the exclusion and/or the prior therapy of an extreme obesity, which can favour the manifestation of an obstructive sleep apnea syndrome.
Airway Obstruction↗
Reconstruction of craniofacial bone defects with individual alloplastic implants based on CAD/CAM-manipulated CT-data.
Reconstruction of craniofacial bone defects by intraoperative modelling of autogenous or alloplastic materials may cause undesirable results concerning the implant shape or the long-term maintenance of this shape. Furthermore, the use of alloplastic materials to be modelled intraoperatively may result in an inflammatory tissue response. Therefore the question is raised whether CAD/CAM-techniques may be used for the pre-operative geometric modelling of the implant based on helical computed tomography data. A numerically based 3-dimensional model of the skull defect serves as the basis for a freeform-surfaces design of the implant shape, position and thickness, using modelling tools and programmes developed for industrial CAD/CAM. The precise and individual fit of the implant results from generating its margins by the borders of the defect, whereas the implant surface is generated by the geometry of the non-affected neighbouring bone contours. The implant data run a numerically controlled milling machine to fabricate the individual implant. The reconstruction of post-traumatic defects of the forehead, of post-surgical temporal defects after intracranial haemorrhage, and of a parieto-occipital defect due to ablative tumour surgery are presented as the first clinical experiences of this new method.
Adolescent↗