Search PubMed⌕ Search

Biomedical subjects

R Schmelzeisen

Publications and source records attributed to R Schmelzeisen.

At least 19 recordsLinked to original sources
PubMed2006

Topographical CT-data analysis of the human orbital floor.

The aim of this study was to evaluate the topographical anatomy of the human orbital floor for the production of prefabricated implants on the basis of computer tomography data. A database of 279 CT scans of Caucasian patients without traumatic deformation of the midface was analysed. 3D-image segmentation of the midfacial skeleton was performed using a computer-assisted protocol. A virtual plane (50 x 50 mm (2)) was constructed using defined landmarks above the orbital floor. An automated procedure was used to measure the distance between the orbital floor and the constructed plane at 400 distinct points. A mathematical algorithm was used to analyse the data, and to calculate a map of the orbital floor. Statistical analysis of the data revealed that orbital floor topography could be classified as distinct clusters. There were 12 variations of orbital floor anatomy: three unique patterns of the orbital floor for the right orbit and three corresponding patterns for the left side, all of which varied between the sexes. The 12 patterns were constructed with a statistical confidence interval of 1.36+/-0.6mm.

Adult↗
PubMed2006

Individually preformed titanium mesh implants for a true-to-original repair of orbital fractures.

The purpose of this investigation is to present the results using preoperatively-formed titanium mesh implants for a true-to-original primary repair of extensive orbital floor and medial wall fractures. Individually preformed implants were used to repair extensive orbital floor injuries in 19 patients at the University Hospital, Freiburg. The form of the orbital floor and walls was analysed by preoperative diagnostic CT scan data. The form of the virtual reconstructed orbit was transformed into a model of the orbital cavity by a template machine. Postoperative imaging by or CT scan verified the exact 3D reconstruction of the orbital cavity 'true to original'. None of the patients demonstrated diplopia or enophthalmos postoperatively. Using individually preformed titanium mesh implants, the accuracy of the 3D orbital reconstruction was within a range of 1mm. The reconstruction using preformed implants proved to be less time consuming, more precise and less invasive, compared to 'free hand' efforts, for the repair of orbital injuries using titanium mesh and calvarial grafts.

Biocompatible Materials↗
PubMed2006

Inferior alveolar nerve transposition--an in vitro comparison between piezosurgery and conventional bur use.

An in vitro comparison between a new ultrasound-based piezoelectric device and a conventional bur was performed for lateralization or transposition of the inferior alveolar nerve to evaluate the effects on soft and hard tissue. Transposition of the inferior alveolar nerve was performed in the cadaver mandibles of 10 sheep: the left nerve was uncovered with a saline-cooled diamond-coated spherical bur (2000 rpm), and the right nerve was uncovered with the piezoelectric device mounted with a spherical diamond tip. The surface, the zone of bone defect, and the nerve were examined by light microscopy and laser microscopy. Bone treated with the rotary bur showed significantly smoother surfaces and shallower defect zones (50 microm) in comparison with the piezoelectric device (150 microm). Lesions of the epineurium and an increased amount of bone particles were found in the lesions prepared with the piezoelectric device. In vitro preparation with the piezoelectric device was more invasive to the bone than was a conventional diamond bur. Touching the inferior alveolar nerve resulted in roughening of the epineurium without affecting deeper structures. The degree of injury was lower than when using the conventional rotary bur.

Animals↗
PubMed2005

Significance of osteoporosis in craniomaxillofacial surgery: a review of the literature.

Osteoporosis is a common problem in orthopedic surgery. The purpose of this review of the literature was to examine whether osteoporosis is also an important factor in patient treatment in the field of craniomaxillofacial surgery. Emphasis was given to the consequences of osteoporosis for the maxilla and mandible, the influence of osteoporosis on fracture treatment, the use of dental implants, the importance of soft tissues and the effect of osteoporosis therapies. It was found that osteoporosis does affect the bones of the skull. The effect of osteoporosis on treatment, however, is controversial and necessitates better ways of quantifying bone loss. Large inter-individual and site-specific differences in bone density, as well as other effects such as removal of teeth, periodontitis, implant insertion, augmentation procedures and altered loading with dystrophic consequences need to be considered in future studies. Special attention should be given to osteoporosis during fracture treatment.

Alveolar Bone Loss↗
PubMed2005

Search for ideal biomaterials to cultivate human osteoblast-like cells for reconstructive surgery.

In this study we cultured human osteoblast-like cells on 16 different biomaterials to find an optimal biomaterial for subsequent use in reconstructive surgery. The tested biomaterials can be divided into five groups: collagen-based membranes of bovine, equine or calf origin, tricalcium phosphate based membranes (alpha and beta), hyaluronic acid based, anorganic bovine bone and anorganic silicone-based membranes. Cell proliferation and cell colonization (Environmental Scanning Electron Microscope, ESEM) analysis were performed. The results of the study demonstrated that four of the examined biomaterial/cell constructs showed a very good proliferation rate and cell density: No. 3 (Tissue Vlies), No. 7 (Sepra film), No. 16 (Biobrane) and No. 17 (Biomend). No favourable group of biomaterials was noticeable. Moreover, the results indicate that these four biomaterials as a part of bone constructs are the best tools for engineering new bone tissue. In contrast, biomaterials No. 19a (Bio-Oss) and 19b (Bio-Oss Collagen) showed the lowest proliferation rates. The result of No. 19b was improved by treatment in the perfusion chamber for 48 h as well as by additional use of vacuum. The present study is an important base for further analysis of biomaterials and consequently for the development of tissue engineering.

Bioartificial Organs↗
PubMed2005

Application of fuzzy inference to European patients to predict cervical lymph node metastasis in carcinoma of the tongue.

In head and neck cancers, the presence of cervical lymph node metastasis is an important determinant of outcome. Many attempts have been made to predict cervical lymph node metastasis, but the accuracy of currently available techniques remains inadequate. We used fuzzy inference to predict cervical lymph node metastasis retrospectively in 75 patients with squamous cell carcinoma of the tongue and prospectively in 23 patients. Our model was based on three variables: tumor size, keratinization, and mode of invasion. The accuracy of fuzzy inference for the prediction of cervical lymph node metastasis in the 75 patients studied retrospectively was 86.7%, the sensitivity was 70.8%, and the specificity was 94.1%. In the 23 patients studied prospectively, the accuracy was 91.3%, the sensitivity was 50.0%, and the specificity was 95.2%. The accuracy obtained in this European series of patients was similar to that previously obtained in Japanese patients. We conclude that fuzzy inference may be a useful method for predicting cervical lymph node metastasis. Its high specificity is likely to reduce the number of unnecessary neck dissections. However, the current level sensitivity is inadequate for routine clinical use. Therefore, other predictors of lymph node metastasis should be identified to refine the current model.

Carcinoma, Squamous Cell↗
PubMed2005

Pathological mandibular fractures following third molar removal.

Seventeen patients, who presented mandibular fractures following third molar removal, were treated in the Department of Oral and Maxillofacial Surgery at the University Hospital Freiburg between 2000 and 2004. Clinical and radiological data were analysed to evaluate the possible risk of fracture following third molar removal. Our data show an increased rate of pathological mandibular fractures in males over 40 years of age, following removal of a difficult lower wisdom tooth with a high retention grade that necessitated bone removal. Fourteen out of 17 fractures occurred postoperatively. In six cases, no fracture was visible in radiographs during the primary investigation. Pathological mandibular fractures were typically located anterior to the mandibular angle (n=15). We recommend informing patients about possible risks and, in selective cases, a soft diet for up to 4 weeks after the operation. A cracking noise reported by the patient is the most important indication of a fracture. If, initially, the fracture is radiologically undetectable, we recommend the use of radiological controls.

Adult↗
PubMed2004

Endoscopic assistance in the removal of a foreign body in the condylar process.

This case report describes the application of the endoscopic technique in the removal of a metallic foreign body in the condylar process in an 81-year-old man. The patient's history indicated 60 years of pain in the left preauricular region as well as complaints of localized headaches. Physical examination revealed multiple scars on the patient's left preauricular region. No limitation of mandibular movement and no joint clicking were detected. Maximal mouth opening was 45 mm. According to the patient, masticatory function was normal. Digital palpation of the temporomandibular joint did not produce pain. Radiographic diagnosis was performed, which showed a pointed metallic foreign body lodged in the left condylar process. The removal of the foreign body was performed under endoscopic visualization via an intraoral approach. A 30 degrees-angled 4-mm diameter endoscope (Karl Storz, Tuttlingen, Germany) with a xenon light source was used.

Aged↗
PubMed2003

Arteriovenous malformation in the temporalis muscle.

An 18-year-old man presented with an arteriovenous malformation (AVM) in the temporalis muscle. It was shown by magnetic resonance imaging (MRI) and confirmed by intra-arterial angiography. The lesion was completely resected and the defect reconstructed with titanium mesh and cancellous bone.

Adolescent↗
PubMed2003

Evaluation of swallowing function after intraoral soft tissue reconstruction with microvascular free flaps.

This study assessed swallowing function after tumour resection and reconstruction utilizing free vascularized flap closures in patients with oral cancer. Swallowing function was evaluated postoperatively in 23 patients (21 men and 2 women) who had undergone reconstruction with either a lateral upper arm free flap (LUFF, n=16) or a radial forearm free flap (RFFF, n=7). Videofluoroscopy was used to assess tongue mobility and abnormalities of swallowing function. All patients who underwent reconstruction with LUFF or RFFF free flaps had decreased tongue mobility, except for the tip of the tongue. Patients who underwent anterior or posterior resection had greater decreases in tongue mobility than those who underwent medial resection. Swallowing impairment was similar in patients with LUFFs and those with RFFFs. Anterior resection of the oral cavity had a significant negative effect on swallowing function. Silent aspiration occurred in five patients. In conclusion the resection site affected swallowing function, but the type of flap did not, in patients with oral carcinoma, who underwent tumour resection with reconstruction

Adult↗
PubMed2003

Comparison of fuzzy inference, logistic regression, and classification trees (CART). Prediction of cervical lymph node metastasis in carcinoma of the tongue.

OBJECTIVES: In this paper three statistical methods [logistic regression, classification and regression tree (CART), and fuzzy inference] for the prediction of lymph node metastasis in carcinoma of the tongue are compared. METHODS: A retrospective collection of data in 75 patients treated for tongue cancer was carried out at the Clinic and Policlinic for Oral and Maxillo-facial Surgery at the University Hospital of Freiburg in Germany between January 1990 and December 1999; biopsy material was used for laboratory evaluations. Statistical methods for the prediction of lymph node metastasis were compared using ROC curves and accuracy rates. RESULTS: All three methods show similar results for the prediction of lymph node metastasis with slightly superior results for fuzzy inference and CART. A great overlap is apparent in the ROC curves. The best result observed for fuzzy inference and CART was a sensitivity of 79.2% [95% confidence interval: (57.8%; 92.9%)] and a specificity of 86.3% (73.7%; 94.3%); the best result for predictions based on the logistic regression was a sensitivity of 66.7% (44.7%; 84.4%) and a specificity of 80.4% (66.9%; 90.2%). Accuracy rates of fuzzy method and CART were higher [accuracy rate for fuzzy method and CART: 84% (73.7%; 91.4%), for logistic regression method: 73.3%, 95%-CI: (61.9%; 82.9%)]. CONCLUSIONS: From a clinical point of view, the predictive ability of the three methods is not sufficiently large to justify use of these methods in daily practice. Other factors probably on the molecular level are needed for the prediction of lymph node metastasis.

Decision Support Techniques↗
PubMed2002

[Extraoral and intraoral endoscopically assisted management of collum fractures].

AIM OF THE STUDY: Using limited extraoral and transoral incisions for an endoscopically assisted open reduction of condylar mandible fractures, the risk of facial nerve damage and extensive visible scars can be reduced. PATIENTS AND METHODS: The endoscopically assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 14 had additional mandibular fractures, and 11 of the condylar fractures were dislocated. Of the 17 patients, 9 were treated by submandibular and 8 by transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approaches using an endoscopically assisted technique. APPROACHES: In four patients angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trocars were not needed in these four patients. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle even when dislocation with lateral override was present. The extraoral approach was used for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗
PubMed2002

[Color duplex ultrasound in monitoring vascularized fibula transplants].

BACKGROUND: For the successful management of vascularized free fibular bone grafts, the early detection of vascular complications is important. When vascular complications are suspected without a reliable monitoring of the graft perfusion, revision surgery often proved to be unnecessary. Color duplex sonography for the postoperative monitoring of free fibular bone grafts without a skin island is demonstrated. MATERIAL AND METHODS: The quantitative and qualitative monitoring of the perfusion of microvascular anastomosis and the transplanted tissues using color duplex sonography with a 7.5-Mhz scanner (Elegra, Siemens, Germany) for the postoperative monitoring of 12 free fibular bone grafts was performed. Using color duplex sonography, the perfusion of the vascular pedicle and the free fibular bone grafts was demonstrated in all 12 free fibular bone grafts. In three patients vascular complications and failure of the bone grafts were suspected due to postoperative complications next to free fibular bone grafts such as abscess formation, wound dehiscence, and disturbances of wound healing. Using color duplex sonography, adequate perfusion of the vascular pedicle and the transplanted tissue was demonstrated and therefore revision surgery not indicated. DISCUSSION: Color duplex sonography is a reliable, noninvasive, and inexpensive method for the postoperative monitoring of free fibular bone grafts.

Ameloblastoma↗
PubMed2002

How to optimize seeding and culturing of human osteoblast-like cells on various biomaterials.

The optimization of seeding and culturing of human osteoblast-like cells on three collagen-based biomaterials (bovine, equine and calf collagen membrane) was studied by cell proliferation and cell colonization (scanning electron microscopy) analysis. Osteoblasts of five patients were seeded onto the three biomaterials and two different parameters were varied: the time intervals between initial seeding and adding culture medium (2 h 6 h. 12 h, 24 h) and the seeding concentration (1 x 10(5), 1 x 10(6), 2 x 10(6)cells/ml) of cells onto biomaterials. The results of the study demonstrated that the time interval between seeding osteoblasts and adding culture medium as well as the seeding concentration effects the cell proliferation and the cell colonization. The best proliferation rate was achieved by adding the culture medium 2 h after initial seeding and with a seeding density of 1 x 10(5) cells/ml. Moreover, all three biomaterials resulted in different proliferation rates. The best proliferation rate resulted with the bovine collagen membrane. In conclusion, the examined parameters are very important for the development of the tissue engineering techniques and in a larger perspective also for reconstructive surgery.

Alkaline Phosphatase↗
PubMed2002

Endoscopy-assisted open treatment of condylar fractures of the mandible: extraoral vs intraoral approach.

By using an endoscopy assisted extraoral and transoral approach for open reduction of condylar mandible fractures with limited incisions, the risk of facial nerve damage and extensive visible scars can be reduced. The endoscopy-assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 13 presented with additional mandibular fractures. Nine of the 17 patients were treated by a submandibular approach and eight by a transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approach using an endoscopy-assisted technique. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle, even when dislocation with lateral override was present. In four patients, angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trochars were not needed in these four patients. The extraoral approach was indicated for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗