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Biomedical subjects

L Freitag

Publications and source records attributed to L Freitag.

At least 37 records · Page 2Linked to original sources
PubMed1996

The role of brachytherapy in the treatment and control of central bronchial carcinoma.

Endobronchial brachytherapy is by far the oldest interventional bronchiological treatment procedure. In the decades following its inception in 1922, it has undergone progressive modification by innovations in radiation physics and techniques, and has enjoyed a renaissance with the introduction of fibreoptic bronchoscopy, local anaesthesia, modern afterloading devices, and high dose rate (HDR) treatment with iridium-192, an isotope with very high activity. However, there is little standardization of dose-specification, fractionation and optimal dosage using this isotope, and homogeneous, objective analyses of the clinical results of treatment using iridium-192 is lacking. Very often, the exact staging of patients is lacking. For such reasons, any evaluation of the efficacy of endobronchial brachytherapy is significantly impeded. However, reliable data are available on the palliative effect of HDR-brachytherapy, which is safe, fast in onset and apparently superior to external beam radiotherapy (EBRT) alone. In addition, some studies document the curative effects, or complications, offers not only an insight into the working principles of radiation treatment but also into the biological behaviour of bronchial tumours. Endobronchial HDR-brachytherapy should be compared to the other interventional procedures focusing on the same aim, namely that of restoring patency of a previously occluded bronchus. This is the overall challenge to pneumologists working in this field.

Brachytherapy↗
PubMed1996

[Experiences with fluorescence diagnosis and photodynamic therapy in a multimodality therapy concept of operated, recurrent bronchial carcinoma].

Even of those few patients who are operated because of bronchial cancer up to a quarter develop a recurrence. One reason is certainly that tumor-cells already present at the time of surgery are bronchoscopically invisible. Fluorescence methods might be able to detect these malignant cells. For patients with post-surgical recurrences the therapeutical choices are limited due to the loss of parenchyma. Photodynamic therapy (PDT) with the hematoporphyrine derivative Photofrin is one laborious but promising option. Based on an argon-dye laser we have developed a combined system for the diagnostical measurement of autofluorescence and Photofrin-induced fluorescence at 488 nm and the therapeutical PDT at 630 nm. Under the excitation with blue light from the argon laser, differences in the autofluorescence of malignant and benign cells can be distinguished. Following the injection of Photofrin a spectrum peak at 628 nm clearly delineates tumor cells. In six out of twelve patients with post-surgical recurrences a single PDT course resulted in tumor eradication. With additional PDT courses and brachytherapies local tumor control could be achieved in all cases. The general photosensitivity and the necessary light protection were tolerated by all patients. In order to avoid severer complications such as asphyxia, obstruction of bronchi and pneumotharaces resulting from fibrin-plugs and necrotic tissue following PDT must be considered. Especially in patients with pneumonectomy a careful surveillance and debridement is mandatory.

Aged↗
PubMed1995

[The dynamic trachea stent for treatment of benign and malignant tracheal obstruction].

Severe obstruction of the trachea is a life-threatening condition. In two patients with a benign cause of obstruction, women of 70 and 71 years old, and in one with a malignant cause, a man of 24 years old, insertion of a dynamic trachea stent led to instant relief of symptoms. The dynamic stent has the advantage over rigid or self-expanding stents that it does not migrate but may be easily removed, that it induces less granulation tissue, and that less mucus retention is seen, because it allows the normal cough mechanism to take place.

Adult↗
PubMed1995

Experimental models of tracheobronchial stenoses: a useful tool for evaluating airway stents.

BACKGROUND: Stent implantation is a conservative alternative to open operation for treating benign tracheobronchial strictures. Most of the presently available stents were primarily designed for endovascular use. Their respiratory use entails a risk of iatrogenic complications. From a scientific and from an ethical point of view these risks justify preclinical evaluation of new respiratory stents in experimental models of central airway stenoses. Therefore, an attempt was made to develop such models in piglets and adult minipigs. METHODS: Tracheal stenoses were obtained by creating first a segmental tracheomalacia through extramucosal resection of cartilaginous arches. The fibrous component of the stenoses was then obtained through bronchoscopic application of a caustic agent causing progressive deep mucosal and submucosal injury. Stenoses of the main bronchi were created by topical application of the caustic agent only. RESULTS: These models demonstrated the typical features of benign fibromalacic tracheobronchial stenoses with constant recurrence after mechanical dilation. Preliminary experiments showed that short-term problems of tolerance of stent prototypes are easily demonstrable in these models. CONCLUSIONS: These experimental models, which simulate quite realistically human diseases, offer the opportunity to perfect new tracheobronchial stents specifically designed for respiratory use and to evaluate their long-term tolerance before their use in humans.

Animals↗
PubMed1995

Tracheal carcinoma and mixed pneumoconiosis. A causal relationship?

We report on a 58-year-old man who had worked as a plumber and fitter for over 41 years and had been exposed to asbestos, man-made mineral fibers and welding fumes. Eighteen months before death, squamous cell carcinoma of the trachea occurred. Energy-dispersive X-ray analysis revealed intrapulmonal dust deposits in accordance with his exposure. A relationship between the tracheal carcinoma and the dust exposure causing a mixed pneumonoconiosis seems to be probable.

Asbestos↗
PubMed1994

Development of a new insertion technique and a new device for the placement of bifurcated airway stents.

We developed a new insertion technique and designed a forceps device for the placement of bifurcated airway stents; 131 of 142 endoscopically placed tracheobronchial Y-stents were inserted with a forceps and a laryngoscope. For the last 52 stent implantations we used the new stent forceps. It was determined to be a simple and safe method without major complications. In 11 cases alternative techniques had to be used. Technique and device are described in detail.

Bronchoscopy↗
PubMed1994

Omentopexy and muscle transposition: two alternative methods in the treatment of pleural empyema and mediastinitis.

From March 1987 to March 1993, 64 patients with chronic empyema and mediastinitis were treated with omentum and thoracic muscle transposition. There were 36 male and 28 female patients, age range 29 to 76 years. 31 patients suffered from chronic empyema and bronchopleural fistula after lung surgery, 18 patients had chronic empyema after pulmonary inflammatory disease, and 15 patients developed a mediastinitis with or without pleural empyema after cardiac surgery or irradiation of the chest wall. The pedicled omentum was used in 33, the thoracic muscles latissimus dorsi, pectoralis major, serratus anterior, and trapezius either alone or combined in 31 cases. There were no perioperative deaths. Bronchopleural fistulas and infected spaces were successfully closed in 61 patients (95.3%). Postoperative CT scan, angiography, bronchoscopy, and lung function tests demonstrate the efficacy of both surgical methods. Omentum pedicle and thoracic muscle flaps supply excellent vascularised tissue to fill infected pleural space and mediastinum, particularly in patients with limited cardiopulmonary function.

Adult↗
PubMed1994

Three years experience with a new balloon catheter for the management of haemoptysis.

For the management of severe haemoptysis we have developed a double-lumen, bronchus-blocking catheter that can be introduced through the working channel of a standard fibrebronchoscope. We wondered whether this catheter would be suitable to control pulmonary haemorrhage in clinical practice. Over a period of 36 months, 30 of these catheters were used in 27 patients with moderate and massive pulmonary bleeding from various lesions. Underlying diseases were: malignancies (11), vascular deformities (5), tuberculosis (4), silicosis (2), carcinoids (2), silicosis (2), endometriosis (1), bronchiectasis (1). In 26 cases, the transbronchoscopic balloon tamponade was successful. In one patient, tumour growth close to the carina prevented securing of the balloon and double-lumen tube intubation was required. There were only minor complications attributable to the balloon. With the catheter in place for up to seven days, patients underwent surgery, received radiation, chemotherapy, drug treatment or bronchial arterial embolization. In conclusion, we found this double-lumen, bronchus-blocking device safe and the technique practicable to control pulmonary haemorrhage.

Balloon Occlusion↗
PubMed1994

Theoretical and experimental basis for the development of a dynamic airway stent.

Three major problems are currently associated with airway stents: mucostasis, formation of granulation tissue, and migration. We wanted to determine whether these problems could be solved by a different stent design. Based on theoretical considerations of an idealized trachea, we developed a dynamic bifurcation stent made of silicone which incorporates horseshoe-shaped steel struts. A flexible posterior membrane enables dynamic compression during cough, whilst the clasps maintain the airway lumen in the face of external compression. The design of the stent cast was based upon computed tomographic (CT)-scan studies of the central airways. Its complex shape provides a smoother distribution of pressure on the mucosa; thereby, lowering the stimulus for granulation formation. The bronchial limbs saddle on the carina, preventing displacement. The mechanical behaviours of the new stent and two commercially available stents were compared in an ex-vivo model, utilizing freshly excised tracheae and new visualization techniques. Dynamic (artificial coughs) and static loads (simulating tumour compression or pleural pressures) were applied on excised human tracheae with different stents. Our dynamic stent preserved effective compression of the posterior membrane in response to cough, and also provided lumen stability against extrinsic compression. In comparison, the two commercially available stents did not provide both functions equally well. In conclusion, our newly designed dynamic bifurcation stent shows characteristics which should prove useful in avoiding problems currently associated with airway stents.

Cough↗
PubMed1993

Scar carcinoma of the trachea after tracheotomy. Case report and review of the literature.

We present another case of squamous cell carcinoma of the trachea developed in a tracheotomy scar. In the literature 6 cases of cancer found in tracheotomy scars or tracheostomies are reported. The patients' ages ranged from 6 to 66 years. The interval between tracheotomy and the occurrence of cancer ranged from 3 to 41 years. Local extirpation and radiotherapy were tried. The use of stents is emphasized.

Adult↗
PubMed1992

[Endobronchial prosthesis: experience report].

Between January 1988 and December 1990 a total of 84 endobronchial prosthesis were implanted in 55 patients at the Ruhrlandklinik, Essen. Bronchial carcinoma (33/55) was the leading indication for placing an endoluminal stent. Since the technique of implantation seldom leads to serious complications, non-malignant tracheobronchial stenosis and malacia play an increasing role in airway stenting. Implantation was usually performed under general anaesthesia and through rigid tube bronchoscopes with enlarged diameters. Most frequently a flexible silicone stent (Dumon) was used, Montgomery (5/84), Gianturco (5/84), Orlowski (4/84) and Strecker stents were also implanted. The respiratory gain was greatest in central stenosis, 79/84 stents were positioned into trachea or main stem bronchus. Permanent and temporary stenting were performed with success. Dislocation and hemoptysis seldom occur, mucus plugging and incrustation were more frequent complications.

Bronchi↗
PubMed1991

The role of bronchoscopy in pulmonary complications due to mustard gas inhalation.

Over the last five years we have repetitively treated a group of 21 Iranian soldiers who developed pulmonary complications as a result of severe inhalation injury due to mustard gas during the Iran-Iraq war. Early respiratory manifestations included hemorrhagic inflammation of the tracheobronchial tree accompanied by severe erosions. Secondary complications consisted of chronic infections, suppurative bronchitis, and extensive stenotic process of the entire tracheobronchial tree with life-threatening sequelae. After a delay of up to 15 months, scars, ulcers, and strictures developed in the central airways. Progressive deterioration of gas exchange was common. At this point, bronchoscopy, both diagnostic and therapeutic, was invaluable in evaluating the conditions in these patients since many required multiple therapeutic bronchoscopies. Repeated bougienage of the stenotic tracheobronchial lesions and laser photoresection of scarring tissue was life-saving. The recurrence rate of stenosis was very high, with intervals of less than six months on the average. One pneumonectomy was necessary, with the excised lung showing bronchiectasis and chronic pneumonia. To this date we have performed 146 therapeutic bronchoscopies. In four patients, silicone stents had to be implanted. One patient received brachytherapy and external beam radiation therapy in an effort to prevent continued scarring and life-threatening stenoses of the tracheobronchial tree. Our experience demonstrates the extreme usefulness of bronchoscopy in the diagnosis and treatment of pulmonary complications due to inhalation of poisonous gases.

Bronchoscopy↗
PubMed1990

Limited and radical resection for tracheal and bronchopulmonary carcinoid tumour. Report on 227 cases.

Bronchopulmonary carcinoid tumours occur at all levels from the trachea to the lung periphery. Over a 20-year period. 227 patients with carcinoid tumour underwent thoracotomy. The age at operation ranged from 14 to 79 years. Haemoptysis, chronic cough, recurrent infection and wheeze were the most common symptoms; 24% of patients were asymptomatic. The primary tumour was within the trachea or the main, lobar or segmental bronchi in 190 patients (83.7%). A variety of surgical procedures were employed: pneumonectomy in 32 patients; lobectomy and bilobectomy including bronchial sleeve resection in 144; segmentectomy in 18; wedge excision in 19; bronchial sleeve only in 5; carinal resection in 2; tracheal resection in 4 and bronchotomy in 3 cases. There was only 1 hospital death in the 227 patients (mortality: 0.44%). Survival at 5 and 10 years in patients with benign carcinoid was 97.5% and 95%, respectively. In patients with the atypical form it was 41.2%. The peripheral carcinoid was usually totally removed by an ample wedge excision or segmental resection and the central bronchial carcinoid by sleeve resection with lobectomy rather than pneumonectomy. The atypical variant, because of the frequency of lymphatic involvement, should be treated as a bronchial carcinoma by radical resection.

Adolescent↗
PubMed1990

[Indications for surgery and results of 207 thoracotomies in children with diseases of the lung, pleura and mediastinum].

Between 1968 and 1988, 207 children with congenital, inflammatory, and neoplastic diseases of the lung, pleura, and mediastinum underwent thoracotomy. In 34 patients indication for operation was a therapy-resistent recurrent spontaneous pneumothorax, in 25 benign and malignant mediastinal tumors, in 26 pulmonary metastases of extrathoracic primary tumors, in 42 bronchiectasis and post-pneumonic empyema with callosity, in 21 bronchogenic and enterogenous cysts. 22 children had benign tumors of the trachea, bronchi, and lung, 5 malignant tumors of the lung and chest wall. In a smaller number of children congenital defects, parasitic cysts, and aspergillomas as well as foreign bodies, were present. The surgical procedure included anatomical and atypical resections, bronchoplastic interventions, exstirpation of tumors and cysts, decortications and partial resections of the parietal pleura. There was no perioperative mortality.

Child↗
PubMed1990

[Procollagen-III-peptide in bronchoalveolar lavage fluid as an index of fibrosis in sarcoidosis and idiopathic lung fibrosis?].

In order to answer the question whether in sarcoidosis and idiopathic pulmonary fibrosis there is a relationship between the activity of alveolitis (T4/T8 ratio in sarcoidosis, number of granulocytes in idiopathic pulmonary fibrosis) and the activity of connective tissue formation (type III procollagen peptide in the BAL fluid) BAL was performed in 12 healthy subjects, 33 patients with type II sarcoidosis, and 26 patients with idiopathic pulmonary fibrosis. In the unconcentrated BAL fluid of the healthy subjects, P3P was not measurable. On the basis of the T4/T8 ratio and P3P in type II sarcoidosis, three groups of patients with possibly different risks of progression were found: 1) T4/T8 normal and P3P not or only mildly elevated, 2) T4/T8 elevated and P3P normal or only mildly elevated, 3) T4/T8 elevated and P3P greatly increased. In patients with idiopathic pulmonary fibrosis, the concentration of P3P correlated significantly with the number of granulocytes and the clinical activity parameters. On the basis of these results, we conclude that P3P levels in the BAL fluid, as a direct measure of connective tissue neogenesis, may be a valuable addition to cellular and immunocytological BAL findings.

Bronchoalveolar Lavage Fluid↗
PubMed1989

High frequency oscillators with adjustable waveforms: practical aspects.

We have shown that several types of high frequency oscillator can be modified to produce non-sinusoidal flow patterns. We are convinced that the ability to adjust the wave form is a useful feature of a high frequency ventilator. As the required energy is related to (frequency) all the machines we have examined are large, heavy and noisy. Some problems could probably be overcome by engineering skill. For this reason we have not presented detailed power charts of our machines (built mostly by us). However, one has to admit that none of the devices is sophisticated enough to satisfy a physician who is not enthusiastic for high frequency ventilation. On the other hand, we have treated several patients suffering from bronchiectasis using a linear motor piston heavier than the patient. Asymmetric oscillations helped to clear the airways of purulent sputum. Despite all the noise and unsophisticated appearance of the machine, it was accepted well by the patients because they felt relief. This suggests that, regardless of all obstacles, research in HFV technology should be continued.

Equipment Design↗