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Biomedical subjects

E Kastenbauer

Publications and source records attributed to E Kastenbauer.

At least 19 recordsLinked to original sources
PubMed2003

Clinical aspects and strategy for biomaterial engineering of an auricle based on three-dimensional stereolithography.

At the present time, the partial and/or complete reconstruction of an auricle from autologous rib cartilage is one of most widely published techniques. In the field of tissue engineering, different techniques have been described to generate cartilage tissue using isolated chondrocytes. The basis of these tissue-engineering techniques is bioresorbable or non-bioresorbable biomaterials, which serve as a three-dimensional cell carrier. Tissue engineering of an auricle requires preformed bioresorbable biomaterials designed to fit the form of a patient's auricular defect. Three-dimensional imaging acquired from computed tomography scans or laser surface scanning has become an important tool in modern medicine. This study represents the preoperative procedures for the reconstruction of an auricle through tissue engineering in accordance with the clinical aspects. Hyaff 11, a hyaluronic acid derivative, was used as a three-dimensional cell carrier for isolated human nasoseptal chondrocytes. The chondrocytes were amplified in a conventional monolayer culture before the cells were seeded on a hyaluronic non-woven mesh and cultured in vitro for 4 weeks. The chondrogenic potential of human nasal chondrocytes in Hyaff 11 was investigated by confocal laser scanning microscopy, histology (toluidine blue) and immunohistochemistry (collagen type II). Computer-aided design (CAD) and manufacture of an auricle model with stereolithographical methods were used for the prefabrication of a bioresorbable three-dimensional cell carrier designed in the form of a patient's auricular defect. The cell carrier used was Hyaff 11, a fully benzyl-esterified hyaluronic acid derivative. Confocal laser scanning microscopy has shown good cell attachment, a homogenous distribution of amplified chondrocytes and a viability of more than 90%. After 4 weeks in vitro culture the human nasoseptal chondrocytes synthesized new cartilage with the expression of cartilage-specific collagen type II. In order to shape a patient's designed scaffold the auricle model was fitted exactly and symetrically to the contralateral side. Subsequently, the mirror image patient-specific model was used to prepare an identical scaffold model made of a fully benzyl-esterified hyaluronic acid derivative. The bioresorbable scaffold that was produced gave a satisfactory representation of auricle structure. Bioresorbable preformed biomaterials in the form of a patient's auricle defect represent an important prerequisite for the tissue engineering of autologous auricle grafts. Hyaff 11 seems to be a promising material for tissue engineering of cartilage transplants, and the application of this approach will improve conventional reconstructive surgery in the future.

Absorbable Implants↗
PubMed2002

[Clinical and epidemiological data of patients with malignomas of the head and neck].

BACKGROUND: The present study describes clinical and epidemiological data of patients with malignomas of the head and neck documented in the Munich Cancer Register. PATIENTS AND METHODS: Data of head and neck cancer patients treated at four departments of head and neck surgery and one of oral-maxillo-facial surgery in the area of Munich from 1978 up to now are reported. RESULTS: Incidence and mortality as a function of age, sex, and tumor localization are described in comparison to clinical and epidemiological data as specified in tumor registers of the Saarland and the USA. Moreover, TNM stages, survival, recurrence, and metastasis rates are presented. CONCLUSION: Based on the documentation of the Munich Cancer Register our study is the first to present a detailed description of clinical and epidemiological data of patients suffering from head and neck malignomas.

Adult↗
PubMed2001

[Obstructive sleep apnea syndrome. Which therapy for which patients].

Obstructive sleep apnea syndrome is defined by the American Academy of Sleep Medicine as a combination of at least five obstructive events per hour of sleep and such other symptoms as daytime sleepiness, ischemic heart disease and stroke. In addition to weight reduction, the use of oral appliances, and continuous positive airway pressure (CPAP), a number of surgical interventions such as uvulopalatopharyngoplasty and maxillomandibular advancement are also available for the treatment of sleep apnea. Since no prolongation of life has yet been shown for most of the therapeutic options, treatment needs to be individualized on the basis of symptoms, clinical findings and compliance.

Humans↗
PubMed2001

[Microtia: technique for external ear reconstruction with autologous rib cartilage].

Various methods for treatment of classic microtia are known. Beside a prosthesis, the most common way of auricle reconstruction is the use of autogenous rib cartilage; a process that requires two to three operations. In the first operation, rib cartilage is harvested from the 6th to the 9th rib. The base of the framework is the 6th and 7th rib cartilage which is taken under preservation of the synchondrosis. To mimic a 3-dimensional structure, the triangular fossa and scapha are carved into the groundplate and the 8th rib is fixed as a helical rim. After optimising the framework, it is placed in a subcutaneous pocket on the mastoid plane. In a second operation, approximately three months later, the auriculocephalic angle is reconstructed with a cartilage wedge, which is covered by a temporalis fascia flap and split skin-graft from the hairbearing skull. Commonly, a third operation is needed for minor refinements. Currently, autogenous rib cartilage is the ideal material available for ear reconstruction resulting in an excellent cosmetical outcome, although harvesting of the cartilage causes a specific donor-site morbidity. Operations improving the hearing ability by building up the external hearing channel and middle ear are mainly done in cases of bilateral microtia. Ear reconstruction with autogenous rib cartilage produces a replicable aesthetic result. The patients should be at least eight years old.

Adolescent↗
PubMed2001

[Local reconstruction of partial auricular defects].

INTRODUCTION: Partial auricular defects are often caused by resection of skin tumors. These patients are mainly older and often in reduced general condition. Therefore very expenditure surgical approaches seem to be dangerous. SURGICAL APPROACH: In most cases the resection of the tumor is possible in local anaesthesia. The reconstruction should be started after maintenance of the final histology. Next to the defect, the localisation leads to the right way of surgical treatment. Localized defects of the helical rim or auricular dorsum, concha and lobulus can be corrected with easy-to-perform local tissue transfers and flaps. Complex auricular defects with additional surgical steps like a neck dissection need general anaesthesia. As result of the preselected patients surgical single step reconstruction-procedure are preferable. In these patients, because of the size of the defect, previous operations or radiation larger local flaps from the neck region or the scalp are necessary. RESULTS AND CONCLUSION: With limited surgical expenditure most patients can obtain an aesthetically satisfying result. This avoids stigmatisation in an area that is hard to hide, which is important to elderly patients as well.

Age Factors↗
PubMed2000

Relapsing polychondritis: a course over 20 years with cerebral involvement.

Relapsing polychondritis is a chronic inflammatory disease associated with an autoimmune disorder in cartilaginous tissue, eyes, labyrinth, blood vessels, and central nervous system. We describe a 75-year-old woman who presented with a 20-year history of dyspnea, inspiratory stridor, and polyarthritis. She developed dysmorphism of both ears and a saddle nose approximately 10 years earlier. Subsequently, she suffered from hearing loss and a tremor. A T2-weighted magnetic resonance imaging scan of the brain revealed multiple, spotted signal intensities. Immunohistochemical analysis of a serum sample showed antibodies to cartilaginous tissue, which were further identified on immunoblotting as antibodies to type II collagen. The extremely prolonged course of disease (>20 years) until a correct diagnosis was made is remarkable. Also, cerebral involvement, which was most likely caused by cerebral angiitis, and which, to our knowledge, has never previously been reported in this form, was detected. Arch Otolaryngol Head Neck Surg. 2000;126:1495-1498

Aged↗
PubMed2000

[Autologous rib cartilage harvesting: operative procedure and postoperative pain reduction].

INTRODUCTION: In reconstructive surgery there is a growing demand for cartilage grafts. For small amounts of autologous tissue, cartilage from the nasal septum or ear concha is a sufficient and reliable tissue, but in cases of extensive defects or higher mechanical load autologous rib cartilage is a commonly used transplant. Nevertheless, a serious donor-site morbidity, especially postoperative pain, has to be taken into consideration. We present a modified technique for harvesting rib cartilage with a consecutive local pain therapy. TECHNIQUE: In contrast to the commonly used incision through all layers of tissue the described technique follows the anatomical structures of skin tension-lines, the fascial and muscle fibers and tissue sliding-planes. Starting with a transversal skin incisions 1.5 cm above the costal arch, longitudinal splitting of the rectus abdominis fascia and muscle, the rib cartilage of the ribs 6 to 8 can be exposed. Grafts in the size of at least 3 to 8 cm can be harvested under preservation of the perichondrium. This technique causes a high degree of stability and good function of the abdominal wall. POSTOPERATIVE PAIN THERAPY: After harvesting rib cartilage most patients complain about extensive postoperative pain. For adequate treatment the local application of a long-lasting anesthetic substance close to the intercostal nerves is helpful. The introduction of a peridural catheter opens the feasibility of continuously applying a local anesthetic for 3 to 4 days directly into the donor-site. This procedure reduces the need for general anesthetics dramatically and prevents further complications. DISCUSSION: This modified technique for harvesting rib cartilage diminishes the donor-site morbidity by reducing the risk of pneumothorax, hernias and functional deficits. Moreover, the local pain therapy assures postoperative wellness and mobility.

Anesthetics, Local↗
PubMed2000

[Subcutaneous preservation of an amputated auricle. Morphological changes].

BACKGROUND: Microsurgical replantation of an avulsed auricle remains a challenge in reconstructive surgery. Secondary reconstruction of a traumatic lost auricle is usually performed using a costal cartilage framework according to well documented techniques or with a prosthesis. In order to minimize donor-site morbidity, various efforts can be undertaken to preserve the amputated auricle by implanting the de-epithelialized cartilage framework in a subcutaneous pocket on the surface of the mastoid. Where preservation is successful, this original cartilage could be used for reconstructive treatment. PATIENT AND RESULTS: This study describes the histologic and immunohistologic changes in a complete traumatic avulsion of the auricle with subsequent cartilage conservation for eight months within a skin pocket. Trauma, preparation and preservation were accompanied by morphologic changes that included generation of local ossification centers and infiltration of fibrous tissue. We compared the macroscopic and microscopic morphology of the amputated part to native elastic cartilage following maximal denutrition and temporary heterotopic implantation in conjunction with atypical tension and pressure properties of the retroauricular pocket. CONCLUSION: In this case, the limited success of cartilage conservation in the subcutaneous pocket required conventional auricle reconstruction with autologous costal cartilage.

Adult↗
PubMed2000

[A new system for the classification of ethmoid polyposis. Effect of combined local and systemic steroid therapy].

BACKGROUND: Nasal polyps are a common disease with in the majority of cases unknown origin. Both the medical and surgical treatment of nasal polyps present a challenge in Otorhinolaryngology. METHODS: We developed a four-stage grading system for nasal polyps based on the endoscopic aspect of more than 300 patients. In a study of 37 patients, treated by systemically (Methylprednisolon 64 mg p.o., decreasing amounts for the first 11 days) and locally (Budesonid 400 micrograms intranasal) applied steroids for 90 days, this staging-system was tested. RESULTS: The mean stage of polyps decreased significantly (p < 0.01) from 2.8 at day 0 to 1.7 at day 7 and further to 1.2 and to 0.7 at day 28 and day 90 respectively. The mean nasal symptom score decreased equally from 1.14 on day 1 to 0.19 and to 0.14 on day 7 and day 28 respectively. To summarize, we observed a significant (p < 0.01) decrease in polyp stages of 75% respectively a significant (p < 0.01) reduction of symptom scores of 93%. CONCLUSIONS: Thus, we present a suitable new grading system for nasal polyps which we applied directly to assess the efficacy of combined local and systemic steroid therapy. It was shown that this treatment can reduce polyps and prevent their recurrence over the observed time.

Administration, Intranasal↗
PubMed1999

[In search of new treatment methods for head-neck carcinoma].

During the past decades the clinical prognosis of head and neck squamous cell cancer has remained unchanged. This indicates that new therapeutic strategies are needed. Cancer prevention strategies focusing on the elimination of carcinogenic substances could help to lower the incidence of this disease. Documentation of the clinical outcome in tumor registers could help to establish a better understanding of tumor biology and adequate treatment of different tumor types. Nevertheless the most promising approach at the current time seems to be the development of new immunotherapeutic treatment regiments. One possible way of future cancer treatment could be the application of bispecific antibodies that redirect immune effector cells to the tumor. A second approach could be in vivo gene therapy with direct intratumoral injections of a gene coding for interleukin-2. This should help to reactivate tumor-suppressed immune effector cells.

Carcinoma, Squamous Cell↗
PubMed1999

[Induction of antitumor immune response in the mouse model after vaccination with B7.1 expressing tumor cells].

The aim of the study was the induction of an antitumor immune response by genetic modification of tumor cells. This was done by transfecting the costimulatory molecule B7.1 into a murine tumor cell line SCCVII/SF in order to increase T cell recognition and to install an immunologic memory. One cohort of immunocompetent mice C3 H/HeN were injected with B7.1 expressing tumor cells, while the control group received parental B7.1 negative tumor cells. In a second step those immunized mice were rechallenged by parental tumor cells and tumor growth was compared to a new control group. Transfection with B7.1 prohibits outgrowth of the SCCVII cell line. Animals that have been vaccinated in this way are partially immune towards a secondary exposition to B7.1 negative tumor cells. Outgrowth of this recurrent tumor is slowed down. Such an immunization builds up an immunologic memory. Vaccination with B7.1 expressing tumor cells lead to a partial protective tumor immunity in the SCCVII-C3 H/HeN mouse model.

Animals↗
PubMed1999

[Navigation surgery in diseases of the paranasal sinuses].

BACKGROUND: Since the mid-80s, endonasal sinus surgery has gained significant importance in the treatment of chronic inflammatory sinus disease. Many surgeons have recognized the necessity of developing new methods to increase the safety of this type of surgery. One of the advancements in increasing the safety of endonasal sinus surgery was the development of computer-aided surgical navigation (CAS) systems. METHODS: Since 1996, we have tried several different CAS systems for difficult surgical procedures in sinus and anterior skull base surgery, mainly revision surgery for chronic inflammatory sinusitis and endonasal tumors. During this time, we tried one electromagnetic ("Insta Trak") and two optoelectric systems ("Surgigate" and "Vector Vision"). RESULTS: In our experience, all systems can be used in endonasal sinus surgery; accuracy was satisfactory and varied between 0.1 and 0.5 mm. There were differences with respect to the time of preparation of the system for surgery as well as to the possibility to use different instruments. CONCLUSIONS: Computer-assisted surgical navigation systems today have gained a degree of accuracy which makes them not only suitable but almost necessary, at least for difficult surgical procedures at the anterior skull base, i.e. revision surgery in chronic inflammatory sinus disease. On the long run, these systems will become mandatory for these kinds of procedures. On the other hand, CAS systems cannot substitute thorough anatomical and surgical training.

Computer Systems↗
PubMed1999

[Influence of nasal obstruction on sleep-associated breathing disorders].

BACKGROUND: The influence of nasal obstruction on sleep associated breathing disorders (SABD) and the controversial effects of surgical treatment are discussed. RESULTS: Complete nasal obstruction caused by nasal packing increases SABD, but varies from patient to patient and depends on age and individual anatomy. Especially patients with preexisting obstructive sleep apnea syndrome (OSAS) can develop severe complications. Some authors found a higher frequency of SABD in patients with nasal obstruction due to anatomical alterations, i.e. septal deviation, while others denied this connection. Major causes for the development of SABD in nasal obstruction include certain reflex mechanisms, increased negative inspiration pressure with a tendency for pharyngeal collapse, and transition to transoral breathing. Intermittent dilatation of the nasal valve using stents or tapes will lead to a decrease of nasal airway resistance and might also result in an improvement of SABD according to some studies, while others did not find any improvement. The results of controversial operative treatment in nasal airway obstruction are also described and include complete healing of high degree OSAS, improvement of sleep quality, and elimination of snoring. On the other hand, surgery might also be completely unsuccessful or even induce OSAS. CONCLUSION: As the effect of any kind of nasal operation on SABD is unpredictable from our present knowledge, the decision whether or not nasal surgery is indicated should depend on the individual situation of the patient. If OSAS is suspected, preoperative and post-operative polysomnography should be performed.

Humans↗
PubMed1999

Clinical utility of LDL-apheresis in the treatment of sudden hearing loss: a prospective, randomized study.

Although the pathogenesis of sudden hearing loss (SHL) is not as yet known, the clinical picture and the frequent association with vascular risk factors make an ischaemic event likely. This study aimed to assess the effect of an extracorporeal procedure (H.E.L.P.) in removing LDL-cholesterol, fibrinogen and lipoprotein (a) from the plasma, on the recovery of hearing SHL. This procedure using the HELP-system was compared with the usual standard treatment with prednisolone, dextranes and pentoxifyllin. We undertook a single centre, prospective, randomized study in which 18 patients were assigned to H.E.L.P.-apheresis and 9 patients were assigned to standard treatment (2:1 randomization). Audiometric and laboratory testing was performed at baseline, 24 h and 6 weeks after start of treatment. Primary endpoint was the improvement of the average pure-tone threshold between 0.125 and 8 kHz after 24 h. Twenty-four hours after H.E.L.P. treatment average pure-tone threshold recovered by 10.4 dB and by 26.4 dB after 6 weeks. The recovery of hearing of the standard treated patients was 5.8 dB and 16.8 dB after 24 h and 6 weeks respectively. LDL-cholesterol, fibrinogen and lipoprotein (a) were significantly reduced in the HELP treated patients compared with standard therapy, resulting in a significant improve in plasma viscosity, erythrocyte aggregation and resistance to oxidative stress of LDL particles. Our results suggest that the clinical outcome of SHL after a single extracorporeal LDL-apheresis is superior or at least equal to the more expensive standard treatment with prednisolone, dextranes and pentoxifyllin. Re-establishment of vascular endothelial function and improved blood rheology may be the underlying cause. These results must be confirmed in larger-scale trials.

Acute Disease↗
PubMed1998

Cartilage tissue engineering with novel nonwoven structured biomaterial based on hyaluronic acid benzyl ester.

The aim of this study was to investigate the possibility of using the benzyl ester of hyaluronic acid (HYAFF 11), a recently developed semisynthetic resorbable material, as a scaffold for the culture of human nasoseptal chondrocytes in tissue-engineering procedures of cartilage reconstruction. Different techniques such as immunohistochemistry, scanning electron microscopy, and confocal laser scanning microscopy were used to study the behavior, morphology, and phenotype expression of the chondrocytes, which were initially expanded and then seeded on the material. The nonwoven cell carrier allowed good viability and adhesivity of the cells without any surface treatment with additional substances. Furthermore, the cultured cells expressed cartilage-specific collagen type II, indicating that they were able to redifferentiate within the scaffold of HYAFF 11 and were able to retain a chondrocyte phenotype even after a long period of in vitro conditions. Nevertheless, the expression of collagen type I, which was produced by dedifferentiated or incompletely redifferentiated chondrocytes, was noticeable. Additional data were obtained by subcutaneous implantation of samples seeded with human cells in the in vivo model of the athymic nude mouse. The results after 1 month revealed the development of tissue similar to hyaline cartilage. This study is promising for the use of this scaffold for tissue engineering of cartilage replacements.

Animals↗
PubMed1997

Susceptibility of isolated rat facial nerve to anaerobic stress.

Ischemic lesions are presumed to be part of many facial nerve pathologies, such as Bell's palsy. The response of facial nerve to hypoxia has not been evaluated previously in an in vitro model. In the present study, the effects of transient anaerobic stress on functional parameters and their recovery were assessed. Extratemporal rat facial nerves were desheathed and incubated in an experimental chamber using solutions containing either low (5 mM) or high (25 mM) D-glucose. In some of the experiments, 40 microM phenytoin or lidocaine was added to observe the effects of membrane stabilizing drugs. Peak height of compound nerve action potential (CNAP), extracellular direct current (DC) potential and latency were measured simultaneously during and after a 40-min period of hypoxia, induced by bubbling the solutions with N2 or application of 3 mM cyanide. This resulted in a rapid decrease of CNAP and a depolarization of the DC potential with a fast and complete post hypoxic recovery. Elevated glucose concentrations led to a slower decline in CNAP and a smaller rise of membrane potential depolarization. This was accompanied by a slower change of latency. However, post-anaerobic recovery was always diminished in the high glucose solutions. In experiments with phenytoin or lidocaine longer impulse conduction during hypoxia was observed. These findings indicate that the availability of energy-rich components underlies the complex array of physiological derangements seen in ischemia. Membrane-stabilizing drugs show an effect on signal conduction during hypoxia and need further exploration.

Action Potentials↗
PubMed1997

In vitro studies of liposome-mediated gene transfer into head and neck cancer cell lines.

The 5-year survival rate of patients with squamous cell carcinoma of the head and neck (HNSCC) has remained poor despite innovative surgery and new radiation and chemotherapeutic strategies. In such patients, gene therapy relying on the modification of tumor cells by gene transfer may have great potential as a new treatment modality in the therapy of HNSCC. In the present study we developed an in vitro model to show the efficacy and technical feasibility of cationic liposome-mediated gene transfer into HNSCC. Five adherent squamous cell carcinoma cell lines were transfected with SV40- or CMV-promoter-driven CAT (chloramphenicol-acetyl-transferase)-expression plasmids using DOTAP as the liposome carrier. The level of CAT expression was shown to correlate directly with the amount of transfected DNA and could be measured by a CAT-enzyme-linked immunosorbent assay. The results of gene transfer by liposome-DNA complexes obtained for all cell lines showed a dose-dependent efficacy correlating to the amount of DOTAP employed. The data demonstrate the successful in vitro transfection of epithelial cell lines with DNA, suggesting its usefulness as a new tool for head and neck cancer therapy in vivo.

Carcinoma↗