Biomedical subjects

M Heiland

Publications and source records attributed to M Heiland.

At least 19 recordsLinked to original sources

PubMed2006

Diagnostic criteria for the detection of mandibular osteomyelitis using cone-beam computed tomography.

OBJECTIVES: To investigate the usefulness of cone-beam computed tomography (CBCT) in cases of suspected osteomyelitis (OM) of the mandible. METHODS: 13 patients with clinical suspected OM of the mandible underwent cone-beam computed tomography with the NewTom QR-DVT 9000. After CBCT revealed signs confirming the diagnosis of OM, biopsies were performed. Only cases in which histology confirmed the OM were included in this study. RESULTS: CBCT sufficiently depicts OM-typical lesions like osteolytic and osteosclerotic areas as well as periosteal reaction, ill-defined cortical borders and sequestra. CONCLUSIONS: Because the local extension of the disease and its relationship to anatomic structures can be sufficiently detected by CBCT, we see an important additional indication for the usage of CBCT. With regard to distinct cases CBCT combined with scintigraphy seems to be a sufficient diagnostic strategy concerning suspected OM.

Adolescent↗

PubMed2005

Intraoperative imaging of zygomaticomaxillary complex fractures using a 3D C-arm system.

After preclinical studies and evaluation of radiation exposures, intraoperative three-dimensional (3D) C-arm based imaging is now available for the facial skeleton. Fourteen patients admitted for surgical treatment of zygomaticomaxillary complex (ZMC) fractures were included in the study. Preoperative diagnostics and surgical treatment were performed as usual. Intraoperatively, after open reduction, a cone-beam computed tomography (CBCT) dataset was generated using the SIREMOBIL Iso-C3D (Siemens Medical Solutions, Erlangen, Germany). After DICOM-import in eFilm Workstation axial, coronal and sagittal reconstructions were evaluated by five examiners with the help of six defined criteria. In our study, secondary reconstructions were available after 6 min, excluding the time needed for the evaluation of the images. Especially the positioning of the isocentre of the SIREMOBIL Iso-C3D proved to be uncomplicated. Because of the size of the datasets, assessment of the symmetry of the malar projection proved difficult. Best scoring results were found regarding the visualization of the fragment position, bony anchorage of the screws and the fitting of the plates. Remarkable was the low level of metal artefacts in primary and secondary reconstructions. In conclusion, our results demonstrate intraoperative CBCT using the SIREMOBIL Iso-C3D suitable for assessment of postoperative results following ZMC reduction.

Adult↗

PubMed2004

[Experiences in the treatment of midfacial fractures using a fixed-angle osteosynthetic system. Biomechanical results].

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.

Bite Force↗

PubMed2004

[Sonography as a training tool for screening of dubious midfacial fractures].

BACKGROUND: In uncertain midfacial fractures, sonography is an alternative first-line imaging modality to conventional radiographs. Patients with sonographically confirmed fractures can then be directly admitted to three-dimensional imaging, resulting in decreased radiation exposure since the conventional radiographs are omitted. MATERIAL AND METHODS: Using a high-frequency linear and curved array scanner in a healthy proband, images of the zygomatic arch, anterior maxillary sinus wall, infraorbital rim, and lateral orbital wall were obtained. For identification and anatomical allocation corresponding navigated ultrasound images of a reference skull were generated and fused with a segmented CT data set. Navigated sonography was reproduced in a patient with orbitozygomatical fracture of the left side. Therefore, the CT data set, performed during preoperative diagnostics, was fused with the ultrasound images. RESULTS: Because of different coupling shapes, the high-frequency linear array scanner was subjectively found to be more suitable for sonography in the field of the zygomatic arch, anterior maxillary sinus wall, and infraorbital rim, and the curved array scanner was better suited for transbulbar sonography of the orbital walls. After coupling sonography with the navigation system and referencing the scanner, it was possible to verify ultrasound findings objectively by navigation of the scanner and fusion with the CT data set. Using the reference skull, ultrasound images corresponding to normal findings were obtained and with the fused CT data, providing colored segmentation of the facial bones, an anatomically correct identification was possible. Clinical application of this tool is described in a patient with left-sided orbitozygomatical fracture. CONCLUSION: By fusion of ultrasound images and corresponding CT data with the help of a navigation system, a sonographic training tool for preliminary evaluation of midfacial fractures is available.

Diagnosis, Computer-Assisted↗

PubMed2004

[Virtual simulation of dental surgery using a three-dimensional computer model with a force feedback system].

BACKGROUND: Selective reduction of bone without injuring inner structures is an essential part of surgical techniques, especially during dental surgery. Virtual drilling is possible using a new simulator. The following illustrates simulation of an apicectomy. MATERIAL AND METHODS: Using the VOXEL-MAN system, a virtual three-dimensional model of a skull was created based on CT data. Both inferior alveolar nerves and apical inflammations of teeth 23, 25, 36, and 35 were virtually simulated. To achieve a realistic drilling effect with the force feedback system, special tools were integrated into VOXEL-MAN to obtain a high resolution of collision recognition. Adding drilling noises further improved the simulation. Spatial 3D perception was possible with the help of shutter glasses. RESULTS: The presented computer model enabled the visual and haptic observation of complex volume-based models and virtual interaction with them. The haptic feeling proved to be convincing because of collision recognition, consideration of drilling parameters, and addition of drilling noises. Via postoperative reconstructions, polydimensional verification of performed drilling routes is possible. CONCLUSION: Using apicectomies as examples, realistic simulation of dental surgical procedures, even in complex anatomical models, is possible. Generally, it is possible to add virtual pathologies in data sets and/or to use anonymous patient data sets to extend the range of simulated surgical procedures.

Apicoectomy↗

PubMed2004

[Radiation exposure and 3 dimensional imaging options of SIREMOBIL Iso-C(3D) for planning surgical dental interventions].

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.

Adult↗

PubMed2004

Intraoperative 3D imaging of the facial skeleton using the SIREMOBIL Iso-C3D.

OBJECTIVES: With respect to high-contrast structures, cone beam computed tomography (CBCT) offers an alternative imaging modality to computed tomography (CT), requiring less radiation exposure. The C-arm system SIREMOBIL Iso-C3D for three-dimensional (3D) reconstruction has made this modality available for intraoperative use. This paper presents the first intraoperative images of the facial skeleton using the SIREMOBIL Iso-C3D. METHODS: Cases of a zygomaticomaxillary complex fracture, a mandibular angle fracture and a bimaxillary repositioning osteotomy are described to demonstrate the application possibilities of this system in maxillofacial surgery. RESULTS: In addition to the uncomplicated handling of the SIREMOBIL Iso-C3D, generally important was the low level of metal artefacts in its primary and secondary reconstructions, even in close proximity to the material. However, it has to be kept in mind that while soft tissues are visualized using CBCT, information about soft tissue quality cannot be obtained. CONCLUSION: The SIREMOBIL Iso-C3D generates intraoperative data sets suitable for the visualization of the facial bones after open reduction of fractures.

Adolescent↗

PubMed2004

Radiation exposure during midfacial imaging using 4- and 16-slice computed tomography, cone beam computed tomography systems and conventional radiography.

OBJECTIVES: Radiation doses were determined to balance risks against usefulness of the different modalities available for the imaging of the facial skeleton. METHODS: An Alderson Rando Phantom, armed with lithium fluoride thermoluminescent dosemeters (TLDs) was exposed using a set of four conventional radiographs (orbital view, modified Waters view, orthopantomography, skull posterior--anterior 0 degrees ), two different cone beam computed tomography (CBCT) (NewTom 9000 and Siremobil Iso-C3D), and multislice computed tomography (CT) modalities (Somatom VolumeZoom and Somatom Sensation 16). TLDs from 14 well defined anatomical sites lying within the primary beam as well as the TLD corresponding to the thyroid gland were evaluated. RESULTS: Multislice CT showed the highest exposure values. Exposure levels of the CBCT systems lay between CT and conventional radiography. Dose measurement for the 16-slice CT revealed nearly the same radiation exposure as the 4-slice system when adapted examination protocols were used. CONCLUSIONS: Selection of the most appropriate imaging modality should be performed in view of the delivered doses, required image quality and information and the clinical circumstances.

Facial Bones↗

PubMed2004

Diagnostic advantages and possibilities for secondary reconstruction of NewTom 9000 data sets using eFilm.

In order to facilitate diagnosis of images generated with the NewTom 9000, the professional DICOM viewer eFilm Workstation was used for evaluation. Primary reconstructions of patient data of one hundred NewTom 9000 examinations were exported to the DICOM format and subsequently imported in the DICOM viewer eFilm Workstation. Multiplanar reconstructions (MPR) and three-dimensional reconstructions were computed for diagnostic purposes. All desired perspectives can be viewed with this software with CT-like printouts, offering several additional features and an uncomplicated print modus. The DICOM viewer eFilm Workstation is an easy-to-use alternative to the standard software provided by quantitative radiology.

Computer Systems↗

PubMed2003

Potentials of ultrasound in the diagnosis of midfacial fractures*.

The aim of this study was to evaluate the application and limitation of ultrasound in the diagnosis of midfacial fractures. Eighty-one patients with radiologically proved fractures of the facial skeleton were included in this study. Examinations were performed using a 7.5-MHz small-part applicator. Another ten patients without facial fractures served as controls with normal sonoanatomical findings. The most important deficiency of ultrasound in the diagnosis of midfacial fractures is the difficult detection of non-dislocated fractures. According to our own experiences, the application of ultrasound in midfacial fractures is most useful for visualization of the zygomatic arch and the anterior wall of the frontal sinus, with immediate imaging after closed reduction avoiding radiation exposure. Moreover, it is restricted to fractures of the orbital margin and nasal bone. If ultrasound is performed as the first imaging modality in cases of suspected facial fractures by an experienced investigator, the visualization of fracture lines can avoid conventional imaging, so that only an indicated CT scan can be added. In doubtful cases, an individual combination of conventional radiographs would be the next step. By this, an overall reduction of radiation exposure seems possible.

Case-Control Studies↗

PubMed2003

[3-dimensional imaging possibilities of thhe mid-face area using digital volume tomography based on a daver study of angle stable osteosynthesis].

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.

Bone Plates↗

PubMed2003

Oral lichen planus in patients with chronic liver diseases.

BACKGROUND: The possible increased risk of oral lichen planus (OLP) in patients with chronic liver diseases is a controversial issue. PATIENTS AND METHODS: We investigated a total of 156 outpatients with known liver diseases for occurrence of OLP. Hepatitis C virus (HCV) infection was proven for 117 patients (75%) and hepatitis B virus (HBV) infection for 16 patients (10.3%). Four patients were coinfected with HCV and HBV. An alcohol-derived hepatic cirrhosis was found in 23 patients (14.7%). Three patients had a biliary cirrhosis and one had a primary sclerosing cholangitis. Patients suspected of having OLP were transferred to the Department of Oral and Maxillofacial Surgery where excisional biopsies were taken. RESULTS: Eight patients had a white alteration of the oral mucosa. OLP was suspected in five of them and was confirmed histologically in four. The alteration of the fifth patient disappeared during continued interferon therapy. CONCLUSION: Our results show that there is no increased prevalence of OLP manifestation in patients suffering from HCV infection.

Adult↗

PubMed2003

3D-imaging of the facial skeleton with an isocentric mobile C-arm system (Siremobil Iso-C3D).

OBJECTIVES: The purpose of this study was to compare three-dimensional (3D) imaging of the facial skeleton using an isocentric mobile C-arm system vs CT. METHODS: A dried human skull was scanned using a Siremobil Iso-C3D and a multi-detector CT (SOMATOM Volume Zoom; Siemens Medical Solutions, Erlangen, Germany) to compare reconstructed data sets. For each group of scans a standard protocol and a high resolution protocol were used. Image quality was analysed using six anatomical and six virtual structures in the primary reconstructed axial images of both data sets of the Siremobil Iso-C3D compared with CT. A receiver operating characteristic (ROC) study was performed with six examiners. RESULTS: The original categorical response data revealed no significant differences in sensitivity and specificity (P < 0.05). However, image quality of the reconstructed images of the Siremobil Iso-C3D was inferior to the CT images, with metal artefacts having a more prominent negative effect. CONCLUSIONS: The Siremobil Iso-C3D produces 3D images of the facial skeleton suitable for imaging osseous structures. No significant differences were found in sensitivity or specificity between the two methods. Metal objects degrade the image from the Iso-C method to a greater extent than those from CT.

Artifacts↗

PubMed2002

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.

Adolescent↗

PubMed2002

[Clinical outcome of re-innervation of radial flaps and latissimus dorsi muscle transplants].

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.

Adolescent↗

PubMed2000

A synthetic peptide derived from the non-structural protein 3 of hepatitis C virus serves as a specific substrate for PKC.

A synthetic peptide corresponding to the amino acid sequence Arg1487-Arg-Gly-Arg-Thr-Gly-Arg-Gly-Arg-Arg-Gly-Ile-Tyr-Arg1500 of the hepatitis C virus (HCV) polyprotein was found to be a selective substrate for protein kinase C (PKC). In the presence of Ca2+, TPA and phospholipid, PKC phosphorylates the peptide [termed HCV(1487-1500)] with a Km of 11 microM and Vmax of 24 micromol x min(-1) x mg(-1). HCV(1487-1500) acts as a competitive inhibitor of PKC towards other peptide or protein substrates and inhibits the kinase activity with an IC50 corresponding to the Km values measured for the substrates. N- or C-terminally deleted analogs of HCV(1487-1500) did not show inhibitory effects and were only marginally or not phosphorylatable. We designed an additional peptide in which the tyrosine residue was replaced by phenylalanine ([Phe1499]HCV(1487-1500)). This peptide was neither phosphorylated by other serine/threonine kinases tested nor by whole cell extracts prepared from PKC-depleted cells. [Phe1499]HCV(1487-1500) was used to monitor the TPA-induced translocation of PKC activity to the particulate fraction in JB6 cells. The use of SDS/PAGE to separate the peptide from ATP and Pi allowed to monitor simultaneously PKC autophosphorylation and phosphorylation of the peptide. The data presented here show that[Phe1499]HCV(1487-1500) can serve as a convenient tool for investigations of PKC activity also in the presence of other kinases in tissues or in crude cell extracts.

Amino Acid Sequence↗

PubMed1999

Characterisation of non-structural protein 3 of hepatitis C virus as modulator of protein phosphorylation mediated by PKA and PKC: evidences for action on the level of substrate and enzyme.

Generally, the maximum activities of the protein kinases A (PKA) and C (PKC) show an optimum value for their substrate concentrations rather than a saturation curve; at high substrate concentrations, the kinase activity is completely abolished. The C- and N-truncated form of the non-structural protein 3 (NS3) of hepatitis C virus (HCV) (HCV-polyprotein-(1,189-1,525)) abolishes the inhibiting effect of the substrate, yielding saturable Michaelis-Menten kinetics of PKA and its catalytical domain (C subunit). In contrast, HCV-polyprotein-(1,189-1,525) activates PKC with increasing Vmax, while it abolishes the substrate inhibition of its catalytical domain (M-kinase) through a mechanism analogous to that of PKA and C subunit. PKC isoforms alpha, beta and gamma investigated are similarly activated by HCV-polyprotein-(1,189-1,525). Our data suggest that NS3 attenuates the substrate inhibition through a generalized mechanism operating mainly on the substrate level that directly results from a specific protein-protein interaction. In the case of the PKC, an additional kinase activating mechanism operates on the enzyme level. Both actions of NS3, the attenuation of the substrate inhibition and the activation of PKC, could not be explained by classical means that predict autophosphorylation to enhance the rate of substrate phosphorylation. The results are discussed in view of similar activities displayed by matchmakers and some molecular chaperones.

Alkylation↗

PubMed1999

[Primary solitary malignant schwannoma of the trigeminal nerve, Report of a case and review of the literature].

We present the case of a primary solitary malignant schwannoma of the trigeminal nerve. A total of 55 cases have been described in the literature; however, in these cases two tumors were affecting the supraorbital branch. This nerve-sheath tumor usually affects men in the fifth decade of life. The main clinical sign of malignant schwannomas of the head and neck is an indolent swelling. Hematogenic or lymphogenic metastasis has not been described. Because of the pleomorphism of the tumor cells immunohistochemical study is important. The treatment of choice is radical resection, possibly with adjuvant radio- or chemotherapy. The 5-year survival rate of malignant schwannoma of the trigeminal nerve is 41.7%.

Aged↗