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Biomedical subjects

N Schwenzer

Publications and source records attributed to N Schwenzer.

At least 19 recordsLinked to original sources
PubMed2002

[Positioning of the premaxilla in cases of bilateral cleft lip, alveolus and palate using Latham's appliance].

UNLABELLED: SUBJECT MATTER: In cases of bilateral cleft lip, alveolus and palate, preoperative positioning of the premaxilla using Latham's appliance has been described. This method is controversial, since it may cause growth defects. PATIENTS AND METHODS: From 1992 to 2000, Latham's appliance was inserted preoperatively into 20 patients with bilateral lip, alveolus and palate clefts with extreme premaxillary protrusion. Pin fixation ensued at the age of 3 months. After adjustment of the premaxilla, the soft palate was closed and bilateral lip adhesion as well as bilateral gingivoperiosteoplasty were performed directly after the removal of the appliance. Final lip closure took place 4-6 weeks later. At the age of 2 years, the hard palate was closed. Evaluation was based on combined face-maxilla models, standard photographs and, when available, lateral skull x-rays showing the relative position of the segments, the influence of Latham's appliance on the nasal septum and the relation of the upper jaw to the skull base and mandibula. RESULTS: In all cases, a satisfactory alveolar alignment was achieved; thickening and curvature of the nasal septum occurred but receded. Neither growth disturbances nor dental germ damage were seen. In two cases, complications arose from suture dehiscence of the lip adhesion: in one patient, a screw defect caused a loosening of the appliance and there was also a transmigration of the postpremaxillary pin. CONCLUSIONS: On the basis of our experience, the use of Latham's appliance, combined with consistent orthodontic supervision and, if necessary, treatment, represents a practical option for the treatment of bilateral cleft lip, alveolus and palate, especially in cases with extreme protrusion of the premaxilla.

Alveoloplasty↗
PubMed2000

[Development of an osteoporosis animal model of the jaw area].

The aim of the following study was to develop an osteoporotic model by means of ovariectomy. Bone mineral density of the upper and lower jaw was measured by dual energy X-ray absorptiometry (DPX) before and after ovariectomy. Histomorphometric measurements were done by a microtomography system. Bone mineral density decreased significantly after ovariectomy in the upper and lower jaw.

Absorptiometry, Photon↗
PubMed2000

[History of the German Society of Oromaxillofacial Surgery].

The German Society of Oral and Maxillofacial Surgery was founded by Martin Wassmund in 1951. One of the main reasons was the need for scientific representation in the council at a medical convention. The Society, originally composed of 52 members, was first called "The German Society of Maxillofacial Surgery". In 1972, it extended its title to include the term "oral" ("Mund") and currently comprises 620 members. A scientific conference is held annually on a specific topic. The lectures given there have been published since 1954 in "Fortschritte der Kiefer- und Gesichts-Chirurgie" (Progress in Maxillofacial Surgery) by Thieme Verlag; since 1997, they have appeared as a Springer-Verlag supplement. Topics of choice are published in "Mund-, Kiefer- und Gesichtschirurgie" ("Oral and Maxillofacial Surgery"), originally by Hanser in Munich and now by Springer-Verlag in Heidelberg. In this manner, it was possible to completely document the scientific activities and progress in this specialty. Each year since 1957, a prize named after M. Wassmund, has been given for outstanding scientific accomplishment. The presidents, convention locations, topics, and prizewinners are listed in a table. Since the founding of the Society of Oral and Maxillofacial Surgery, close cooperation has existed with the National Association of German Oral and Maxillary-Facial Surgeons (Bundesverband der Deutschen Arzte für Mund-Kiefer-Gesichts-Chirurgie). In order to intertwine scientific and political interests, a fusion of these two organizations is planned for the year 2000.

Germany↗
PubMed2000

Neo-osseous flaps using demineralized allogeneic bone in a rat model.

Surgical reconstruction with revascularized bone grafts can be compromised by donor tissue limitations and may be refined by prefabrication of compound neoflaps using bone substitutes. The principal suitability of demineralized allogeneic bone (DALB) slabs in fabricating neo-osseous flaps based on the inferior epigastric vascular system was studied and compared with neoflaps with autologous bone (AUB). In 45 rats, the histological pattern of bone formation in response to angiogenesis induced by vessel implantation was assessed, and characteristics of vascularization of the neoflap were studied microangiographically at 2, 4, 6, and 8 weeks. Histological techniques included decalcified and nondecalcified sections, as well as intravital polyfluorochrome labeling. Blood flow of the neoflap was also assessed quantitatively using 15-microm microspheres labeled with technetium 99-methylene diphosphate (99-MDP) 8 weeks after flap fabrication. Although the DALB neoflaps showed consistent bone formation and neovascularization, the bone regeneration process was delayed distinctly in comparison with AUB. Microangiographically, however, no differences between the two types of grafts became apparent during all time periods tested. Furthermore, the radioactivity of the DALB neoflap, which means bone blood flow per dry weight, was significantly higher than in AUB grafts and even more than that of intact iliac bone (p = 0.001). The exact meaning of elevated blood flow in DALB and similar degrees of vascularization corresponding to native AUB grafts remains to be determined, but may be a sign of ongoing bone formation resulting in a suitable DALB-containing neo-osseous flap in the long term. The authors findings support that allogeneic bone could be a potential substitute for AUB in creating a prefabricated neo-osseous flap.

Angiography↗
PubMed1999

[Endosseous implants after tumor resection of the face].

Endosteal implants after tumor surgery of the face are helpful in reconstructing facial defects. A retrospective study of our patients treated using craniofacial implants was conducted to evaluate long-term results. A total of 128 implants were inserted, 110 implants in the periorbital, 12 implants in the mastoid, and six implants in the paranasal region; 113 implants were short craniofacial Brånemark implants, and 15 implants were dental implants. The success rate for implant survival was 94.5%. Long-term results were promising and more than satisfactory, leading to a large indication for these endosteal implants.

Facial Bones↗
PubMed1999

[Microsurgical anastomosis of the bone transplant as implant site in the maxilla].

A total of 27 vascularized iliac crest segments and four vascularized scapula transplants were transferred to achieve masticatory rehabilitation in 31 patients suffering from extensive maxillary defects; 83 Brånemark implants and 16 IMZ implants were inserted 4-8 months after the bone transplantation. The implants were uncovered 6-8 months after insertion. All patients were provided with a bar-fixed, removable prosthesis. At an average insertion period of 4.5 years, the implant loss rate was 18.8%. The effectiveness of a combination of microsurgical bone transplantation and implantation in treating serious maxillary defects is thus demonstrated.

Alveolar Ridge Augmentation↗
PubMed1999

[Surgical therapy of basalioma of the facial skin].

The present investigation reviews the history of 673 patients having undergone surgical treatment for 1301 BCC of the face between 1977 and 1992 at our department. Based on this series the features with bearing on the surgical strategy, such as type, size and location of the lesions, will be outlined. Emphasis is put on the variants of local flap reconstruction and skin grafting techniques, particularly in the problem zones of the nose and eyelids, where no excess skin for closure of the defect is available. Throughout the whole series histologic control of the adequacy of marginal and deep tumor resection was performed. It became obvious that the required ranges for clearance to tumor edges and removal in depth cannot be predefined arbitrarily or on pure clinical judgement. Frequently a two-stage procedure of resection and repair will be necessitated. Recurrences during the mandatory follow-up were thoroughly reassessed to identify the reason for failure (e.g. accuracy of histologic category, multifocal growth, predisposition) and related to the time span from primary excision. Our series confirms that morphologically controlled surgical excision of the BCC of the face and subsequent application of reconstructive techniques produces both safe oncologic and esthetic results.

Adolescent↗
PubMed1999

Evaluation of markers of deep vein thrombosis in patients undergoing surgery for maxillofacial malignancies.

During and following significant surgical intervention, deep venous thrombosis prophylaxis by application of anticoagulants is routinely used. However, patients with malignant disorders are subject to an especially high risk of deep venous thrombosis progressing in severe cases to subsequent pulmonary embolism. The present study focuses on appraising modern markers of deep vein thrombosis in 34 patients undergoing major maxillofacial surgery, with some malignant disorders. No significant differences between the two patient groups were noted using the markers of the kallikrein-kinin-system. From the first postoperative day plasma levels of the coagulation indicator thrombin-antithrombin-III complexes were significantly higher in the group of tumour patients. Markers of fibrinolysis indicated corresponding results: on the first postoperative day tissue-plasminogen activator values rose to 18.9 +/- 3.2 micrograms/l in the group of malignant patients, but only to 7.4 +/- 1.1 micrograms/l (P < 0.05) in the control group. Also postoperative D-dimer concentrations in the malignancy group were significantly above those of the control group. In the present study it could be demonstrated that patients with malignant neoplasia undergoing major maxillofacial surgery are exposed postoperatively to a particularly high risk of developing thromboembolic complications. All in all, the status of anti-thrombotic therapy requires reappraisal with respect to the current treatment approach adopted in tumour patients.

Antithrombin III↗
PubMed1999

Retention force of magnets in endosteal implants used for facial prosthesis.

This study reports on forces generated by magnets to retain facial prostheses. The retention force was measured in cylindrical magnetic inserts and in telescope magnetic inserts. The forces between insert and secondary magnets were measured at different angles. The mean force in the axial direction was 1.8 N. The force decreased as the angle between force direction and insert-axis increased. The results will help clinicians to insert implants in an optimal position when using them to retain facial prostheses.

Analog-Digital Conversion↗
PubMed1998

[Median craniofacial clefts. Therapy recommendations and late outcome].

Median craniofacial clefts are classified as median facian cleft deformities and are characterized by clefts of the nose involving the skull base. They can be accompanied by hypertelorism and/or encephaloceles. From a total of 22 of our patients with median deformities, three encephaloceles and two severe median nasal clefts with hypertelorism were considered in 2- to-8-year-olds. Two children with severe brain deformities died before the commencement of therapy. The remaining median deformities were corrected as soon as possible, whereby exclusively soft-tissue surgery was performed during the first year of life and in no case later than school admittance. Final corrections on the nasal skeleton were made after the age of 12. No growth disturbances of the middle face or jaw occurred subsequent to craniotomies and corrections of hypertelorism. Plate osteosynthesis has proven to be the most reliable method of stabilization; we removed the osteosynthetic material in all cases. The multiplicity of possible deformities requires that procedures be tailored to the individual case.

Adolescent↗
PubMed1998

[Effect of early fronto-orbital advancement on growth of the frontal sinus and supraorbital area].

In 12 patients with craniosynostosis the influence of early fronto-orbital advancement on the growth of the frontal sinus and supraorbital region was examined. A follow-up examination at the age of 8 years showed a lack of pneumatisation of about 50%. However, there was no correlation between this score and the external contour. The frontal sinus has no dominant influence on the growth of the supraorbital region. In 9 out 12 of cases the very early operation time did not lead to disturbances of growth. A further follow-up examination of the patients after termination of growth at the age of 16 is planned.

Child↗
PubMed1998

[Using individually designed ceramic implants for secondary reconstruction of the bony orbit].

The use of autogenous transplants and the application of intraoperatively customised alloplastic materials show, in cases of secondary orbital reconstruction, a higher postoperative morbidity caused by additional approaches to the transplant donor site. On the other hand, thorough surgical exploration and fitting of the transplants or alloplastic materials greatly prolongs operating times. For these reason we designed ceramic implants (Bioverit) on the basis of stereolithography models and prefabricated them using a commercially available dental copy milling unit (Celay). In five cases up until now seven customised implants have been inserted for reconstruction of the lamina papyracea, zygomatic complex and infraorbital floor and rim. Encouraged by the good postoperative aesthetic and functional results, with significantly reduced operating times and morbidity in all cases, we will continue to take this technique into account for reconstruction after complex orbital fractures.

Adult↗
PubMed1998

Relevance of SCC-Ag, CEA, CA 19.9 and CA 125 for diagnosis and follow-up in oral cancer.

The prognosis of oral cavity carcinoma is limited by recurrent disease or lymph node metastasis. Secondary to surgery and radiotherapy, anatomical structures are often severely changed and make early diagnosis of renewed tumour growth by clinical and radiological examination difficult. We studied the course of serum SCC-Ag, CEA, CA 19.9 and CA 125 in 121 patients with untreated squamous cell carcinoma of the head and neck (SCCHN) before and after therapy and evaluated their relevance for diagnosis and follow-up in oral cancer. CA 19.9 and CA 125 seemed to be useless for this tumour entity. CEA resembled more the alcohol consumption and smoking habits of the patients examined than their state of disease. Only SCC-Ag correlated with the tumour burden and represented the disease course. In the event of relapse, half the patients had an exponential increase in SCC-Ag, 1-2 months prior to diagnosis.

Alcoholism↗
PubMed1998

Complications after microsurgical tissue transfer in the head and neck region.

In recent years, the use of microsurgically re-anastomosed free transplants has become a proven technique for the reconstruction of defects in the head and neck region, which is demanding from both aesthetic and functional points of view. A retrospective catamnestic study on 227 free tissue transfers in the Department for Oral and Maxillofacial Surgery at the University of Tübingen showed good healing with relatively low failure rates of the transplants used. A significant proportion of local complications, arising postoperatively, was to some degree due to pre-existing medical conditions, tumour-specific pretreatments and the particular wound-healing situation found in head and neck interventions. The highest relative rate of complications at the site of origin was seen amongst osteomuscular transplants (20%) whilst (fascio) cutaneous and visceral transplants were found to result in a low percentage of problems (4%). In contrast, the healing of iliac crest transplants was accompanied by various local complications in 12% of the cases, slightly higher than 20% amongst (fascio) cutaneous and abdominal transplants and well above 30% for latissimusdorsi and scapular transplants. General complications, in particular of a respiratory and/or psychiatric nature, were found in 23% of the patients.

Adult↗
PubMed1998

Orbital reconstruction with individually copy-milled ceramic implants.

Diagnostic advances such as computed tomography and new surgical techniques have dramatically improved both the functional and aesthetic outcome of orbital reconstructions. Taking a further approach, we designed ceramic implants (Bioverit) on the basis of stereolithographic models. After copy milling a resin template with a commercially available dental unit (Celay), the prefabricated implants were inserted for reconstruction of the lamina papyracea (n = 1), zygomatic complex (n = 2), infraorbital floor (n = 5), and rim (n = 3). Intraoperatively, only slight modifications of the implants had to be performed. The results were encouraging, as all cases showed a good aesthetic and functional postoperative outcome. Preoperative evaluation of the osseous defect and prefabrication of the required implant reduced operating time and patient morbidity significantly.

Adult↗
PubMed1997

[Oral, facial and cranial manifestations of von Recklinghausen neurofibromatosis (NF)].

19 patients with neurofibromatosis (NF) type 1 were evaluated retrospectively. Many patients presented not only with orocraniofacial neurofibromas but also with cranial skeletal deformities--involving skullbase, skull, orbit, midface and mandibula--and ophthalmological and dental symptoms, as well as neurological disorders. Malignant transformation of NF was observed in 1 case. Severe manifestations of NF were associated with the plexiform growth type. Due to the nature of NF surgical treatment most often is only palliative.

Adolescent↗