[Experiences in the treatment of midfacial fractures using a fixed-angle osteosynthetic system. Biomechanical results]. / Osteosynthetische Versorgung von Mittelgesichtsfrakturen mit einem multidirektionalen winkelstabilen Plattensystem. Biomechanische Ergebnisse.

AIM: Fixed-angle osteosynthetic systems are characterized by mechanical "locking" of the osteosynthetic screw and plate. These systems have found increasing acceptance and use for osteosynthetic fixation and temporary reconstruction of the mandible. The aim of this study was to investigate the applicability and performance of fixed-angle systems in the treatment of midfacial fractures. MATERIAL AND METHOD: A newly developed fixed-angle osteosynthetic plate system (smart lock) was compared to a conventional system using fresh human skulls. The iatrogenically produced zygomatic fractures of the human skulls were treated by osteosynthesis and biomechanically tested. Furthermore, in a dynamic test series, an artificial bone was subjected to an alternating force of 15 N of up to 1,000,000 cycles. The new screws and plates were subjected to further biomechanical tests. RESULTS: The tests using the fixed-angle implants revealed that an increase of stability of up to 40% can be expected after osteosynthetic fixation. Furthermore, the plates resisted 1,000,000 cycles of alternating forces, whereby the conventional systems failed after 170,000 cycles on the average. CONCLUSION: Fixed-angle systems, due to their construction, provide a high degree of stability even in thin bones of the midface. They appear to be promising for the treatment of midfacial fractures.

[Radiation exposure and 3 dimensional imaging options of SIREMOBIL Iso-C(3D) for planning surgical dental interventions]. / Strahlenexposition und dreidimensionale Darstellungsmöglichkeiten des SIREMOBIL Iso-C(3D) zur Planung chirurgischer Zahnsanierungen.

BACKGROUND: Preoperative dental X-ray diagnostics of multimorbid, non compliant patients requiring dental surgery are often insufficient. The SIREMOBIL Iso-C(3D) has made intraoperative 3D imaging available, even for the facial skeleton. This modality was used intraoperatively in two patients referred for surgical dental treatment. Furthermore, radiation exposure of the SIREMOBIL Iso-C(3D), an orthopantomography and a complete dental status was compared. MATERIAL AND METHODS: An Alderson-Rando phantom was exposed to ten cycles of the SIREMOBIL Iso-C(3D) using the fast mode (50 projections). In comparison 28 panoramic views of an Orthophos and 10 sets of 14 dental images using the Oralix DC with a quadrate mask were applied. Twenty-five anatomically defined TLD positions were analyzed. Furthermore, SIREMOBIL Iso-C(3D) was used in one patient by performing 100 projections and in a second patient by performing 50 projections. After DICOM-import in eFilm, axial, coronal, and sagittal reconstructions were evaluated by five examiners regarding defined criteria. RESULTS: The radiation exposure level of the SIREMOBIL Iso-C(3D) was lower than in the complete dental status and only slightly higher in comparison with the orthopantomography, although the system requires the highest number of single projections. Quantitative evaluation of the visualization and recognition of defined structures proved to be very good and good in most points. However, limitations of the system became obvious regarding apical processes. CONCLUSION: Because of the dosimetry results and the visualization of the relevant structures, in patients for whom preoperative images cannot sufficiently be performed, the intraoperative use of the SIREMOBIL Iso-C(3D) as a base examination is justified.

[3-dimensional imaging possibilities of thhe mid-face area using digital volume tomography based on a daver study of angle stable osteosynthesis]. / Dreidimensionale Darstellungsmöglichkeiten des Mittelgesichts mithilfe der digitalen Volumentomographie anhand einer Kadaverstudie zur winkelstabilen Osteosynthese.

BACKGROUND: Multidirectional angularly stable interlocking plate systems are now available for the surgical treatment of the midface. After first experiences in cases of mandibular fractures, application to the facial skeleton was investigated using a cadaver study. Furthermore, three-dimensional imaging by means of the digital volume tomograph NewTom DVT 9000 after reduction of orbitozygomatical fractures was performed and evaluated. MATERIAL AND METHODS: After artificial osteotomy and reduction of both zygomatical complexes, osteosynthesis of the left side was performed with three 4-hole miniplates (2.0). On the right side, three angular stable 2-hole plates (2.3) were used. Thereafter, a three-dimensional data set was generated using the NewTom DVT 9000. After DICOM-import in eFilm reconstructions were evaluated by six examiners regarding defined criteria. RESULTS: After adaptation and fixation of the angular stable interlocking plate system without complications, manual checking revealed that the primary stability did not seem inferior to the other side. Defined criteria were sufficiently evaluable, even close to the osteosynthetic material, using reconstructions of the digital volume tomography data set. CONCLUSION: Surgical treatment of midfacial fractures using a multidirectional angularly stable interlocking plate system seems promising. The NewTom DVT 9000 proved to be suitable to visualize even fine osseous structures of the midface.

[Clinical outcome of re-innervation of radial flaps and latissimus dorsi muscle transplants]. / Klinische Ergebnisse der Resensibilisierung von Radialislappen und Musculus-latissimusdorsi-Transplantaten.

BACKGROUND: The necessity of nerve anastomosis in an attempt to regain cutaneous sensitivity following flap transfer has been the basis of many discussions. In our study, we investigated the degree of sensory recovery with emphasis on the different nerval qualities on the radial forearm and the latissimus dorsi flap. COLLECTIVE: Sixty-two patients with 66 latissimus dorsi flaps and 19 patients with a radial forearm free flap were examined. RESULTS: Except for five latissimus dorsi and two radial forearm flaps, all flaps investigated showed clinical signs of sensory recovery, whereby the degree and quality of cutaneous reinnervation varied. In comparison, neural reconstruction did not lead to any clinical improvement. CONCLUSION: Based on our clinical results, we consider nerve reconstruction during radial forearm and latissimus dorsi free flap transfer unnecessary. To what extent this can be said for other flaps requires further investigation.

Clinical and histological results of sensory recovery after radial foreann flap transfer.

The necessity of nerve anastomosis in an attempt to regain dermal sensitivity following pedicled or free-flap transfer has been the basis of many discussions. In our study, we investigated the degree of sensory recovery with emphasis on the different nerval qualities, on the radial forearm flap and correlated it to the histological and immunohistological findings. Nineteen patients with radial forearm free flap--five of whom underwent nerve anastomosis--were examined. The follow-up interval was 20.3 months (average) after surgical intervention. Histological examinations were performed on 13 of the 19 patients, in eight cases on one occasion and in five on more than one occasion. Seventeen patients experienced sensory recovery, whereby the degree and quality of dermal innervation varied. In comparison, the nerval reconstruction did not lead to any significant improvement. Based on our clinical results, we regard the nerve reconstruction during the radial forearm free flap transfer as unnecessary. To what extent this can be said for other flaps demands further investigation.