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Biomedical subjects

K Schwager

Publications and source records attributed to K Schwager.

At least 19 recordsLinked to original sources
PubMed2005

[Malignant paranasal sinus tumors. Diagnosis, therapy and results].

BACKGROUND: Malignant neoplasmas of the paranasal sinuses are rare and present usually in advanced tumor stage due to the lack of early clinical symptoms. PATIENTS AND METHODS: In the last 10 years, 63 patients with paranasal malignancies were treated at the Department of Otolaryngology, Head and Neck Surgery of the University of Würzburg. 33% of the patients showed an occupational exposition (wood-processing or metal industry). At the time of the first visit to our institution 95% of the patients presented with an extensive disease, staged T3 and T4. Adenocarcinoma (24%), squamous cell carcinoma (22%) and malignant melanoma (19%) were the most common histologies. Surgery combined with radiotherapy was the treatment strategy in 55 patients (87%). RESULTS: Patients with a complete surgical resection showed a higher 5-year-survival rate (77%) than patients with an incomplete resection (56%). In 38% (n=21) of the patients treated with surgery and radiotherapy, a local recurrence of the tumor was observed. This recurrence localised in the skull base and/or the orbita/periorbita occurred most frequently in the first (46%) or the second year (31%). CONCLUSION: The prognosis of malignant paranasal tumors depends mainly on the control of the local tumor growth. Modern strategies of surgical treatment in combination with radiotherapy need to be implemented in an effort to achieve a continuous remission.

Adenocarcinoma↗
PubMed2004

[Postoperative bleeding after tonsillectomy between 1985 and 2001 and experiences to perform laser tonsillotomy].

BACKGROUND: Tonsillectomy is one of the most often performed surgery in our specialty. But postoperative bleeding is not only a statistic risk, it can lead to a tragic end individually. In the future and according to the DRGs, a postoperative stay in hospital for more than 6 days will be difficult to realise. METHODS: 10 052 patients after tonsillectomy were measured, 7663 were performed in the ORL-Department of Würzburg, 2389 in the ORL-Department of Augsburg. Further data was measured by questioning the parents of 65 young children after lasertonsillotomy. PATIENTS: The patient group of the tonsillectomies included all ages, the group of the lasertonsillotomies included young children aged 1- 6 years. RESULTS: The first spike of bleedings of the ORL-Department in Würzburg was found within the first 24 hours after surgery. A second spike showed between the 5 (th) and 7 (th) postoperative day, an other after the 8 (th) and 15 (th) postoperative day. In the ORL-Department Augsburg the main spike was found from the 7 (th) until the 9 (th) postoperative day. No postoperative bleedings were found in the lasertonsillotomies. CONCLUSIONS: A postoperative stay in hospital is sufficient for 3 days, but should vary individually. On young children with symptomatic hyperplasia of the tonsils a lasertonsillotomy should be performed.

Adult↗
PubMed2003

[Ceramic model for temporal bone exercises--an alternative for human temporal bones?].

BACKGROUND: The complexity of the temporal bone anatomy makes it necessary to train in a model before starting middle ear surgery. The classical object are human cadaver temporal bones, but these are not always available for different reasons. Alternatively in cooperation between the department of otolaryngology, head and neck surgery of the University of Jena and the 3di company Jena, Germany, a calcium sulfate based model was developed. METHODS: During a temporal bone course at the Bugando Medical Centre, Mwanza, Tanzania, these ceramic temporal bone specimens were used for training. Because of the lack of drills, the specimens were worked on in chisel and carving technique. All participants were beginners in ear surgery. Classical procedures in mastoid surgery were performed: Exposing of sigmoid sinus, facial nerve, labyrinth, dura, jugular bulb and internal carotid artery. RESULTS: The temporal bone models were very useful for these exercises. Good exposure was possible for the dura, the facial nerve and the major blood vessels. The possibility of exposing tinier structures like the labyrinth was still insufficient. Nevertheless the understanding of the 3-dimensional anatomy of the temporal bone using the ceramic model was excellent. The relationship of all important anatomical structures could be taught intensively. CONCLUSIONS: Particularly for beginners or in cases where human temporal bones are not available the calcium sulfate based temporal bone is an alternative training model for mastoid and middle ear surgery.

Calcium Sulfate↗
PubMed2002

[Cylindrocarcinoma in a patient with Brooke-Spiegler syndrome].

BACKGROUND: Cutaneous cylindromas are benign adnexal tumors that may occur as a solitary lesion or in a multiple familiar pattern. Malignant change is rare. The association of multiple trichoepitheliomas and cylindromas, the so called Brooke-Spiegler Syndrome, is supposed to be inherited in an autosomal dominant manner. PATIENTS: A 55 year old woman presented with multiple skin tumors on the scalp, as well as the nasolabial and periauricular area since the age of 20 years. Her daughter and her nephew were also affected. Tumors were surgically removed for cosmetic reasons and showed histological signs of benign cylindromas and trichoepitheliomas. 35 years after diagnosis patient presented with a large exulceration on the right occipital area with intracranial invasion. Staging revealed multiple metastases in both lungs. Patient died 1 month later. RESULTS: Histological examination showed beside zones of massive necrosis multiple mitosis. The jigsaw puzzle pattern and the thick PAS positive basal layer, the striking characteristics of benign cylindromas, were lost. These histological findings and the clinical presentation led to the diagnosis of cylindrocarcinoma. CONCLUSIONS: Cylindrocarcinoma is an aggressive tumor with tendency to a local destructive growth and metastases. As malignant transformation of a benign cylindroma occurs more often in the multiple form a close follow-up of patients with multiple cylindromas is necessary. A family study is indicated.

Carcinoma, Adenoid Cystic↗
PubMed2002

[Titanium as a material for ossicular replacement - basic aspects and clinical application].

BACKGROUND: The use of titanium as a biomaterial in ossicular chain reconstruction is increasing. The situation for integration of biomaterials is more difficult in the semiopen implantation site middle ear than in other parts of the body. Important for integration is the contact of the biomaterial's surface toward proteins. Studies of the integration in living tissue still have to be performed in animal experiments. Morphological examinations of explanted prostheses after clinical use complete the picture of an ossicular replacement material. METHODS: Preclinical studies where performed to compare the adsorption behaviour of titanium, stainless steel and aluminum oxide toward radioactive marked albumin and native collagen type I. An animal model in the rabbit was performed to study the integration of titanium in the middle ear morphologically. Middle ear prostheses removed during revision surgery were studied as well. RESULTS: Titanium showed an adsorption amount of 360 microgram/cm(2), stainless steel of 230 microgram/cm(2) and aluminum oxide of 500 microgram/cm(2) out of an albumin solution of 400 mg/ml. Comparing desorption the mean loss was 16 % for titanium, 21 % for stainless steel and 23 % for aluminium oxide. Reassembled collagen fibrils could be detected after adsorption in collagen type I solution by means of scanning electron microscopy. Morphological studies in animal experiments showed regular healing after implantation. Explanted prostheses from humans did not show any cellular signs of repulsion. CONCLUSION: The results of preclinical studies and clinical use demonstrate titanium as a useful material for ossicular reconstruction in middle ear surgery.

Absorption↗
PubMed2001

[Carcinoma of the external ear canal and middle ear as interdisciplinary challenge for ear surgery and radiotherapy].

BACKGROUND: Carcinoma of the external auditory canal are tumours considered to have a poor prognosis. Improvement of the survival rate by surgical means alone is not possible. Individual therapy modalities as a result of an interdisciplinary approach between otosurgeon and radiotherapist are necessary. PATIENTS AND METHODS: A series of 30 patients (3 patients pretreated at other institutions) with carcinoma of the external auditory canal and middle ear treated between 1978 and 1997 in our institutions was analysed with particular reference to tumour size and its relation to surrounding tissues, patterns of neck node involvement, surgical procedures, and radiation techniques. Clinical endpoints were freedom from local failure, overall survival, disease-free survival. The mean follow-up was 4.7 years (range: 0.1 to 18.8 years), median 3 years. RESULTS: Treatment by surgery and radiotherapy resulted in an overall 5-year survival rate of 51%. According to Pittsburgh classification the 5-year survival rate for early disease (T1- and T2-tumours) was 89%, for stage III 67% and for stage IV 39%. Most important prognostic factors were dural infiltration (all patients with dural invasion died within 2.2 years) and the infiltration of surgical margins (the 5-year survival rate of patients with complete tumour resection was 100%, but 54% in patients with tumour beyond surgical margins). 192-iridium HDR afterloading brachytherapy based on 3D CT-treatment planning is an effective tool in the management of local recurrences following surgery and a full course of external beam radiotherapy. CONCLUSIONS: Surgical resection followed by radiotherapy adapted to the stage of disease and grade of resection is the preferred treatment of cancer of the external auditory canal and middle ear.

Adult↗
PubMed2001

[Diagnosis, treatment and results of malignant skull base tumours].

BACKGROUND: Malignant tumours of the cranial base are rare and present usually in advanced tumour stage due to the lack of early clinical symptoms. PATIENTS AND METHODS: Sixty patients with malignant tumours infiltrating the skull base were treated at the Department of Otorhinolaryngology Head and Neck Surgery, University of Würzburg between 1987 and 1999. Most of the tumours (n = 51) originated from the nose or paranasal sinuses, the epipharynx, the outer ear canal or the middle ear. Seven tumours were malignant brain tumours infiltrating the bony structures of the skull base or originated from the cranial base itself. Two patients suffered from metastases of an adenocarcinoma of the prostata. The histological diagnosis was confirmed in 53 patients preoperatively and in seven patients during tumour resection. Squamous cell carcinoma (n = 24), adenocarcinoma (n = 10) and sarcoma (n = 7) were the most common histologies found. RESULTS: A radical en bloc resection of the tumour was only possible in 26 out of 60 cases. A surgical tumour reduction with postoperative radiation therapy was performed in seven patients as a palliative approach. Eight patients underwent a combined radio- and chemotherapy according to the histological diagnosis. Primary radiotherapy was the treatment of choice in eleven patients, where the tumours were located in the central area of the cranial base. Palliative radiotherapy or solely medical pain control were applied to eight patients who presented either with distant metastases or an advanced tumour growth. The mean postoperative survival following radical surgery was 48 months and after primary radiotherapy 27 months. DISCUSSION: A statistical analysis of the results is not applicable due to the great variety of the disease concerning the histological diagnosis, the tumour size and the location as well as the small number of patients.

Adenocarcinoma↗
PubMed2000

[Second primary carcinomas in the upper aerodigestive tract in different locations and age groups].

BACKGROUND: Second primary tumors are of great importance for diagnostics, therapy and prognosis in patients suffering from squamous cell carcinomas of the upper aerodigestive tract. The clinical observation of an increase of second primaries was the reason for analyzing all patients with head and neck cancer treated for a certain period of time at our institution. METHODS: The hospital charts of 576 patients treated for squamous cell carcinoma of the oral cavity, the oropharynx, the hypopharynx and larynx treated from 1993 till 1996 at the Department of Otolaryngology, Head and Neck Surgery of the University of Würzburg were reviewed retrospectively. RESULTS: 10.1% of all patients developed a second primary tumor. The rate was highest for patients with carcinoma of the oral cavity (17.5%), followed by tumors of the hypo- and oropharynx (11.7% and 11.5%) and the larynx (6.4%). Besides the location, younger age was detected as a risk factor for the formation of second malignancies. The latency between first and second primary tumor was 2.9 years in average. 31% of the second primaries were detected synchronous, 39% metachronous. CONCLUSION: The results demonstrate that younger patients and patients with carcinomas of the upper digestive tract need a consequent follow-up. The development of second primaries even years after the first malignoma demonstrates the necessity of lifelong follow-up and oncological care.

Adult↗
PubMed2000

[Scanning electron microscopy findings in titanium middle ear prostheses].

BACKGROUND: Titanium as a biomaterial in ossicular replacement has widely spread within the last couple of years. METHODS: 23 prostheses (12 PORPs, partial ossicular replacement prostheses and 11 TORPs total ossicular replacement prostheses) removed during revision surgery were studied using scanning electron microscopy. The average implantation time was 8 (range 3-15) months. The specimens were investigated regarding tissue growth, epithelialization, inflammation and cellular signs of rejection. RESULTS: Only few prostheses were totally covered by connective tissue or epithelium due to technical problems in removing the implant and the covering tissue as one specimen. But this offered the possibility to study the interface at the edges where the tissue was torn off. The connective tissue looked unremarkable. Polygonal squamous epithelium was detected on several implants. Respiratory epithelium with ciliated cells and mucus producing goblet cells was seen in two specimens. In cases of cholesteatoma or protrusion the explanted prostheses showed typical rosette-like formation of hornifying squamous epithelium. According to underlying disease a lymphocytic infiltration could be seen. There were no cellular signs of incompatibility noticed neither macrophages nor foreign body giant cells. CONCLUSIONS: From these investigations titanium seems to be a favorable biomaterial for ossicular replacement with good acceptance also in an implantation site showing chronic inflammation.

Cholesteatoma, Middle Ear↗
PubMed1999

Carcinoma of the external auditory canal and middle ear.

PURPOSE: To evaluate therapeutic modalities used at our institutions regarding local control, disease-free survival and actuarial survival in carcinoma of the external auditory canal and middle ear, in an attempt to provide guidelines for therapy. METHODS AND MATERIALS: A series of 27 patients with carcinoma of the external auditory canal and middle ear treated between 1978 and 1997 in our institutions were analyzed with particular reference to tumor size and its relation to surrounding tissues, patterns of neck node involvement, surgical procedures, and radiation techniques employed. Clinical endpoints were freedom from local failure, overall survival, and disease-free survival. The median follow-up was 2.7 years (range 0.1-17.9 years). RESULTS: Treatment by surgery and radiotherapy resulted in an overall 5-year survival rate of 61%. According to the Pittsburgh classification, the actuarial 5-year survival rate for early disease (T1 and T2 tumors) was 86%, for T3 tumors 50%, and T4 stages 41%. Patients with tumors limited to the external auditory canal had a 5-year survival rate of 100%, patients with tumor invasion of the temporal bone 63%, and patients with tumor infiltration beyond the temporal bone 38%. The rate of freedom from local recurrence was 50% at 5 years. Unresectability by dural and cerebral infiltration, and treatment factors such as complete resection or resection with tumor beyond surgical margins are of prognostic relevance. All patients with dural invasion died within 2.2 years. The actuarial 5-year survival rate of patients with complete tumor resection was 100%, but 66% in patients with tumor beyond surgical margins. 192Iridium high-dose-rate (HDR) afterloading brachytherapy based on three-dimensional computed tomography (3D CT)-treatment planning was an effective tool in management of local recurrences following surgery and a full course of external beam radiotherapy. CONCLUSION: Surgical resection followed by radiotherapy adapted to stage of disease and grade of resection is the preferred treatment of cancer of the external auditory canal and middle ear.

Adult↗
PubMed1999

Free-flap reconstruction for laryngeal preservation after partial laryngectomy in patients with extended tumors of the oropharynx and hypopharynx.

Partial laryngeal resection often results in major aspiration problems, making larynx preservation during surgical removal of tumors of the oropharynx and hypopharynx impossible. However, free flaps can be used to reconstruct perilaryngeal tissue, thus preserving the larynx and ensuring a better quality of life for patients. We present the results of forearm free-flap reconstruction of the supraglottis in 22 patients who underwent resections of extended squamous cell carcinomas of the oropharynx and hypopharynx. A total of 9 patients had T3 lesions and 13 had T4 lesions. All patients were additionally treated with radiation therapy alone (to 70 Gy) or in combination with chemotherapy (Cisplatin; 5-fluorouracil). The mean follow-up was 2.4 years. In four patients, tracheostomy could be closed. Five patients suffered from severe aspiration, one of whom had to undergo a laryngectomy. Six patients had mild aspiration and 7 patients had no aspiration, but extensive edema made decanulation impossible. A total of 13 patients were free of disease, 4 patients died of disease, 1 patient died as the result of a second primary cancer and 1 patient died of other causes. Three patients are alive with persistent tumor. Although the majority of patients experienced a better quality of life as a result of larynx preservation, aspiration has remained a problem following treatment.

Adult↗
PubMed1999

[Outcome after resection of extensive oropharyngeal carcinomas and defect coverage by microvascular anastomosis of a radialis flap].

BACKGROUND: Extensive tumors of the oropharynx require an open approach and plastic reconstruction for good oncologic and functional results. PATIENTS AND METHODS: From January 1988 through December 1996 at the Department of Otolaryngology, Head and Neck Surgery, of the University of Würzburg, 62 patients with extensive tumors of the oropharynx underwent surgical treatment (T2 = 6, T3 = 24, T4 = 32). In 40 patients, the resection was performed via a median mandibulotomy approach, in 22 patients using a lateral pharyngotomy. All patients underwent postoperative radiotherapy up to 70 Gy. RESULTS: Using the Kaplan-Meier method, the five-year survival was 80% for T2, 52% for T3, and 22% for T4. Four patients (7%) presented with a second primary carcinoma, and one also had a third carcinoma. Seven patients who died of T3- and T4-tumors had distant metastases, among them 5 patients who were free of local disease. A regular oral diet was possible on average 14 days postoperatively. All patients underwent tracheostomy. Ninety percent of them were decanulated one year postoperatively. CONCLUSIONS: Resection of extensive carcinomas of the oropharynx and microvascular reconstruction produces good oncological and functional results. The best access to extensive tumors is provided by a mandibulotomy. The advantage of this excellent approach outweighs an increasing morbidity in occasional cases.

Combined Modality Therapy↗
PubMed1998

Titanium as a biomaterial for ossicular replacement: results after implantation in the middle ear of the rabbit.

The middle ear poses unique challenges when finding suitable materials for ossicular reconstruction, primarily because of its link to the external environment via the eustachian tube and, hence, its greater exposure to infectious agents. In this study, the biocompatability of titanium was examined in the middle ear of rabbits by using light and scanning electron microscopy. Implants were placed as middle ear prostheses or as free implants. These were inspected at 28 days, 84 days, 168 days, 336 days and 504 days following implantation for mucosal coverage, percent epithelization and any sign of foreign-body reaction. After 28 days, the prostheses were covered by regular mucosa. Although a majority of the free implants took up to 336 days for complete epithelialization, some of the free implants were not epithelialized even at day 504. There were no inflammatory cells observed on the surface of the material, nor were unusual amounts of fibrous tissue seen. In addition, the titanium material exhibited an affinity toward bone. The results of this animal experiment indicate that titanium is a favorable material for ossicular replacement prostheses.

Animals↗
PubMed1998

Ionomeric cement implants in the middle ear of the baboon (Papio ursinus) as a primate model.

Faced with an inadequate supply of autogenous materials, the otologic surgeon may have to utilize various alloplastic materials to reconstruct bony middle ear structures. Allogenic materials have fallen into disfavor clinically because of the possible spread of infections. Implantation of the hybrid bone substitute ionomeric cement in viscous or hardened physical states into the middle ears of a primate animal model was undertaken in order to be able to approximate as closely as possible conditions found clinically. The posterior meatal wall was replaced by freshly mixed ionomeric cement in nine baboons (Papio ursinus). After repositioning the meatal flap, the residual skin defect was left to secondary epithelialization. After removal of the stapes superstructure, incus and malleus head, a columella of hardened ionomeric cement was trimmed to the appropriate size and inserted between the footplate and the malleus handle. In three cases the prosthesis shaft was fixed in position with freshly mixed cement near the footplate. The time of follow-up ranged from 47 to 277 days. Gross sections were obtained without decalcification (using a Zeiss saw microtome) and stained with Giemsa solution. In no instance was there any spontaneous epithelialization of the external meatus, although occasional granulation was seen to develop at the free edge of the flap and subepithelially. Epithelialization of the alloplastic columellae occurred as early as 42 days post-implantation. Over the middle ears reconstructed with the viscous cement, there was growth of a thickened epithelium that partially tended to granulate. On light microscopy, the bony footplate area was found to be unaffected by the cement that had been applied when still fluid. Our findings indicate that reconstruction of the posterior meatal wall with the viscous ionomeric cement can be useful clinically. The material does not become dislocated but, as with all other alloplastic materials, spontaneous overgrowth of the adjacent meatal skin is unlikely to occur. The early epithelialization of the columellae and their middle ear compatibility and biostability give support to the excellent tolerability of the ionomeric cement. At present, complications occurring during otoneurological application of the material necessitated its commercial withdrawal from the market in May 1995.

Animals↗
PubMed1998

[Epithelialization of titanium prostheses in the middle ear of the rabbit. Possible model of mucosa development].

BACKGROUND: The epithelialization of middle ear implants is regarded as a sign of biocompatibility of the implant material. METHODS: The mucosal coverage of titanium was studied in the middle ear of rabbits in light microscopy. Implants were used as middle ear prostheses or as a free implants. Studies were performed after 28, 84, 168, 336, and 504 days. RESULTS: The prostheses were seen to be covered by regular mucosa after 28 days. The free implants were not seen to be totally epithelialized even after 504 days. There were no inflammation cells on the surface of the material, nor were unusual amounts of fibrous tissue observed. The middle ear mucosa was initially thickened, but soon returned to normal values. CONCLUSIONS: The results of this animal experiment show that titanium is a suitable material for ossicular replacement.

Animals↗
PubMed1998

Lymphadenopathy: differentiation of benign from malignant disease--color Doppler US assessment of intranodal angioarchitecture.

PURPOSE: To differentiate reactive from malignant lymphadenopathy by using color Doppler ultrasonographic (US) findings of intranodal blood vessels. MATERIALS AND METHODS: Color Doppler US was performed in 117 lymph nodes in 100 consecutive patients before performance of surgical biopsy (47 nodes), neck dissection (62 nodes), or high-speed core biopsy (eight nodes). The presence of malignant changes in intranodal angioarchitecture (focal perfusion defects, aberrant course of central vessels, displacement of intranodal vessels, subcapsular vessels) was evaluated in each node. Inter- and intraobserver variability were evaluated. RESULTS: Histopathologic examination demonstrated 48 reactive lymph nodes (longest diameter +/- standard deviation, 13.5 mm +/- 6.0), 56 nodal metastases (longest diameter, 19.2 mm +/- 8.8), 12 malignant lymphomas (longest diameter, 23.2 mm +/- 10.5), and one node infiltrated by Langerhans cell histiocytosis. At color Doppler US, 103 (88%) nodes were classified correctly, with a specificity of 77% and a sensitivity of 96%. Reproducibility was 90%-96% (kappa = 0.79-0.91, P < .001). CONCLUSION: Color Doppler US is a reliable and reproducible method for help in the differentiation between reactive and malignant alterations of superficial lymph nodes by using findings of intranodal angioarchitecture.

Adolescent↗