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Biomedical subjects

M Schrader

Publications and source records attributed to M Schrader.

At least 127 records · Page 7Linked to original sources
PubMed1990

Vitreous carbon: a new material for middle ear ventilation tubes.

Synthetic allotropic carbons have been used for nearly 20 years as biomedical implants. Vitreous carbons in particular appear to possess very favourable biocompatibility characteristics. The middle ear compatibility of Sigradur has been tested in the mastoid bulla of gerbils. The period of implantation varied from 1 to 13 months. Light and electron-microscopic examination revealed good middle ear tolerance of the material, especially when the surface had not been modelled. Our animal experiments suggest that this material could be suitable for ventilation tubes, but was less ideal for ossicular replacement prostheses, particularly because of the specific surface properties. Consequently, we have used such carbon ventilation tubes in 38 patients. The results obtained using this material were excellent thanks to the favourable biocompatibility, advantageous surface properties, and low weight.

Animals↗
PubMed1990

Immunohistologic findings in otosclerosis.

The cause of otosclerosis is still unclear. Between 1981 and 1988 we obtained 186 biopsy specimens of otosclerotic bone during the course of stapedectomies. Serial sections of the specimens were examined histologically (H & E) and immunohistologically (peroxidase-antiperoxidase technique) for immunoglobulin G, immunoglobulin M, and C1q and C3 complements. Active otosclerotic foci were found in 61 cases, 43 of which had IgG deposits. IgM antibodies were absent. In specimens with inactive otosclerosis, IgG and IgM were not evident, C1q and C3 complements were demonstrated together with IgG, but sometimes also in the mucosa independent of the phase of the otosclerosis. Our findings suggest that an immunologic process may be important in the pathogenesis of otosclerosis.

Acute Disease↗
PubMed1990

MR imaging of the postoperative lumbar spine: assessment with gadopentetate dimeglumine.

This study defines the accuracy of gadopentetate-dimeglumine-enhanced MR imaging in patients with failed back surgery syndrome by comparing the imaging studies with surgical findings in a large patient population. From June 1988 to March 1989, 193 postoperative patients had MR imaging of the lumbar spine both with and without contrast administration. Of this group, 27 had repeat surgery at 31 levels: these patients comprise the study group. Postcontrast MR diagnoses were as follows: scar only (n = 4), disk only (n = 13), scar and disk (n = 9), and no aberrant epidural tissue (n = 5). Surgical diagnoses differed from the MR diagnoses in two patients at two levels. In one patient, disk was diagnosed on MR while osteophyte was present at surgery. In the other patient, scar only was diagnosed by MR but disk and scar were present at surgery. These data, when combined with the authors' previous experience, give pre- and postcontrast MR a 96% accuracy in differentiating scar from disk in 44 patients at 50 reoperated levels. For patients 6 or more weeks past surgery, sagittal and axial T1-weighted MR imaging before and after administration of gadopentetate dimeglumine is an effective method of evaluating the postoperative lumbar spine.

Adult↗
PubMed1990

[Pulse oximetry: an indicator for the closure of a tracheostome after lateral fixation of the vocal cords (cordopexy)].

The aim of the study was to establish an objective method to predict proper breathing after the closure of the tracheostomy in patients operated upon for laryngeal diplegia by lateral cordopexy. The method is non-invasive, quantitative and independent of the patient. The study covers 18 patients in whom the closure was performed after fixation of the vocal in whom it was performed prior to the operation. The arterial oxygen saturation was measured during closure using a beat-to-beat pulse oximeter and compared with the open tracheostomy, with the closed tracheostomy at rest and under stress, and finally with the closed tracheostomy in the recovery phase. The effort was continued for 5 minutes or until the patient complained of shortness of breath (3 patients). Initially the O2 saturation in these patients did not drop below 90%, but respiratory dependent saturation variations were noted. During the recovery phase, the saturation fell below 90%. The subjective declaration of "asphyxia" always preceded the variations in the O2 saturation. From this, and from the O2 saturation curves, we conclude that the cause for the reopening of the tracheostomy comes more from a circulatory problem that from hypoxemia.

Humans↗
PubMed1990

[Malignant hemangiopericytomas in the head and neck area].

Since 1975 we have treated nine patients with a malignant haemangiopericytoma. Three patients died 5, 9 and 14 years later of metastasis in the lung, liver, skeletal system and mastoid. However, five of the patients are still alive. Regular clinical and radiological follow-up is performed, the average period of follow-up being 8.2 years. Four patients suffered local recurrence within 1-5 years. Surgical resection was the primary therapy in five cases, supplemented in two cases by local radiation. Recurrences were treated by surgery on four occasions and six by radiation, but no complete remission was achieved. Chemotherapy (CyVADic regimen) was attempted in three patients with metastases and one patient with a huge local recurrence, but proved to be ineffective. A re-examination of the histological specimen of all primary tumours and recurrences did not reveal a correlation between histological appearance and clinical behaviour. Our experience in the treatment of malignant haemangiopericytoma and the data in the literature suggest that primary resection with a wide safety margin is the therapy of choice. Radiotherapy is recommended for incomplete resection, local recurrence, and metastases and inoperable tumours. Since recurrence and metastasis can occur after many years (up to 7 years in our patients) a lifelong regular follow-up is necessary.

Adult↗
PubMed1989

[Timing indications for plastic surgery interventions in burns in the area of the neck and across joints].

From 1985 to 1988, 120 patients underwent opertations. 200 times because of deep dermal or total dermal thermal injury. On the basis on the pathophysiology of tissue repair and scar contracture after burns as well as our experience we conclude that the first aim of the surgeon should be to avoid granulation tissue, the precursor of contracting scars. Only the immediate transplantation of autologous skin onto the surgically created wound after excision of burned tissue can halt the repair process. Flaps are the treatment of choice for reconstruction of existing contracturs deep in the fascia.

Burns↗
PubMed1989

[Osteochondrosis of the cervical spine as a cause of globus sensation and dysphagia].

Dysphagia and globus hystericus can be caused by disorders of the cervical spine. Functional disorders of the upper cervical spine are the most common cause of dysphagia and globus hystericus due to vertebral disease. Prominent osteophytes of the ventral spine occasionally cause these complaints. In these cases the operative ablation of the osteophytes is effective. This is demonstrated in the following report, and the indication for operation is discussed.

Cervical Vertebrae↗
PubMed1988

Differential diagnosis of verrucous carcinoma in the oral cavity and larynx.

Two cases of local metastasing verrucous carcinoma (oral cavity and larynx) are presented. Difficulties in the histological diagnosis are demonstrated. Histological criteria of verrucous carcinoma are discussed in comparison to leucoplakia, papilloma, pseudoepitheliomatous hyperplasia, verrucous hyperplasia, and highly differentiated squamous cell carcinoma (grade 1). The importance of correct diagnosis for further diagnostic and therapeutic procedures is pointed out.

Aged↗
PubMed1988

[Long-term results following reconstruction of the tendon of the extensor pollicis longus muscle by transposition of the tendon of the extensor indicis muscle].

Twenty-six patients with injury of the tendon of the extensor pollicis longus have been studied and the long term results of the transfer of the tendon of the extensor indicis are reported. Using Geldmacher's evaluation scheme for assessment of the results of extensor tendon reconstruction we found thirteen excellent, ten good, and three fair results. The prognosis is dependent upon the kind of injury and the time after injury of the transfer of the tendon of the extensor indicis.

Adolescent↗
PubMed1988

[Filling pressures (pulmonary capillary pressure, indwelling catheter) in combined static (handgrip) and dynamic (bicycle ergometer) stress in postinfarct patients].

79 male post-MI patients (mean age 50 years) underwent Swan-Ganz catheterization using handgrip (1.5 min using both hands at 1/3 of the maximum voluntary capacity), bicycle ergometry and a combination of both: handgrip added after 4 min of ergometry at each level of ergometry, a mean of 3 months after MI. Our aim was to determine to which level of dynamic exercise the chosen handgrip exercise could be compared; furthermore, to examine the left ventricular reaction (PCP) under these combined conditions, because it mimics daily life situations. Using this combination of tests, it should be possible to identify patients who should avoid static work. Our findings were as follows: 48 of the 79 patients showed pathological PCPs. Comparing the same level of double product, no significant differences of PCP were found between dynamic and combined static + dynamic exercise. Our handgrip exercise can replace dynamic exercise of 40 W. 19 patients showed highly pathological PCP reactions with delta PCP greater than or equal to 10 mm Hg following handgrip exercise. This extreme PCP reaction did not correlate with the appearance of ST-segment depression in the exercise ECG, nor with either infarction scar size nor heart volume as estimated by X-ray. These findings demonstrate the importance of a staticdynamic exercise combination in evaluating PCP reactions in post-MI patients. The test allows one to select those MI patients who should avoid isometric work.

Cardiac Catheterization↗
PubMed1988

[Improved diagnosis of laryngeal lipoma by computerized tomography].

Isolated lipomas of the larynx are rare. This condition can be difficult to differentiate from other benign lesions such as retention cysts, or laryngocoeles. However, the CT scan achieves a considerable improvement in the pre-operative diagnosis. Fat tissue shows a typical uniform low attenuation value on the CT scan and is the only soft tissue with a density less than water (zero Hounsfield units) that can be imaged. Therefore, CT not only reveals the extent of the tumor, but also establishes the lipomatous nature of the tumor with a high degree of probability. We report one case of an intrinsic laryngeal lipoma.

Aged↗
PubMed1987

[Nuclear magnetic resonance tomography: a new imaging diagnostic procedure of the petrous bone and cerebellopontile angle].

Nuclear magnetic resonance imaging (NMRI) is a new technique enabling three dimensional scanning of the petrous bone without ionizing radiation. Contrary to computer tomography NMRI enables visualization of the structures of the inner ear and the cerebello-pontine angle without masking by overprojecting bony structures. The resolution of inflammatory processes and tumors is excellent. NMRI is inferior to CT in demonstrating bony destruction, and is therefore not so effective in the evaluation of glomus tumours. The use of surface coils in combination with a special gradient-zoom-technique allows high resolution imaging. This and Gadolinium-DTPA for enhancement opens new perspectives in the diagnosis of small acoustic neuromas.

Cerebellar Neoplasms↗
PubMed1987

[Incidence of kidney diseases in inner ear disorders].

A retrospective study is reported based on a questionnaire sent to family doctors and otolaryngologists. Of 213 patients with various inner ear disorders, 19 were found to have renal disease. A further 19 patients were found who had abnormal laboratory and urinary tests. There was no increased frequency of renal disease compared with the normal population nor were there any differences in immunological findings. Experimental findings of renal and inner ear disorders are discussed. The serological data of the patients investigated are compared with etiological considerations of sensorineural hearing loss. This was no correlation of the clinical data with anatomical, physiological or experimental findings in the kidneys and cochlea.

Autoantibodies↗
PubMed1987

[Lymphatic metastases of verrucous carcinoma (Ackerman tumor)].

Verrucous carcinomas (Ackerman tumors) are rare. The tumor is slow growing, locally invasive and is not supposed to metastasize. It is therefore thought to be unnecessary to perform a neck dissection. Two patients with local metastazing verrucous carcinomas (oral cavity and larynx) are presented. The possibilities of therapy are discussed with reference to the two cases presented and according to the literature.

Aged↗