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Biomedical subjects

W Matthäus

Publications and source records attributed to W Matthäus.

At least 19 recordsLinked to original sources
PubMed1995

[Cryotherapy of malignant eyelid tumors].

The treatment of tumors of the eyelids must extend not only to complete removal or destruction of the neoplasm, but also to the maintenance of physiology functions. In addition, cosmetic aspects should be taken into consideration. In a prospective study, 278 cryosurgical operations performed for lid tumors in the years from 1980 to 1985 were followed up for 5 years to decide whether cryotherapy fulfilled these demands. We used spray freezing with liquid nitrogen, because the low temperatures and high freezing rates required for cell destruction are achieved only by this technique. The 5-year recurrence rate was 3.5%. The liquid nitrogen therapy is especially suitable when the eye lids are operated on, because the lacrimal system remains functional. Gas expansion cryotherapy should not be used in in the treatment of tumors, as it may lead to stimulation of growth.

Aged↗
PubMed1991

[Cryotherapy in the treatment of vitreous hemorrhage of various origin].

In 54 eyes from the same number of patients transconjunctival cryotherapy was performed (12 points and 8-10 circular ones in the outer retinal periphery) to influence the absorption of vitreous haemorrhages of different aetiology. The most frequent cause was the proliferative stage of diabetic retinopathy (53.7%) and vascular changes in atherosclerosis (39%). Haemorrhage of the vitreous persisted on average for five months. Eight months after the intervention complete or partial reabsorption led to improvement of the eyesight in 74% of the patients, no change was recorded in 16.6% and further deterioration occurred in 9.4%. No serious per- or postoperative complications were recorded, the method is unpretentious, can be used in ambulatory patients, it is repeatable and suitable also as preparation before vitreous surgery.

Adult↗
PubMed1990

[Technic and long-term results of cryogenic epilation in trichiasis and distichiasis].

The present paper communicates the technique and results of cryoepilation in 1,690 cases (94% trichiasis and 6% distichiasis). Only nitrogen cryotherapy devices are totally suitable for this, and the spray freezing method is to be preferred. The IKG unit developed by the authors, which has proved successful in particular for tumor therapy, is also ideal for cryoepilation. It generates a very tightly bundled nitrogen spray jet, thus permitting isolated freezing of the lid margin. In about 95% of the cases permanent epilation is achieved without undue trauma. In 5% the condition described by Fraunfelder as "secondary trichiasis" develops. Ocular pemphigoid is not a contraindication to cryotherapy.

Cryosurgery↗
PubMed1989

[A new device technic for cryotherapy of glaucoma].

With nitrogen cryotherapy, the authors achieve lasting normalization of intraocular pressure in more than 90% of their primary glaucoma cases. To accomplish this, the therapeutic parameters (working temperature, diameter of the applicator tip, duration of application, number of application points, applicator contact pressure) must be strictly defined and coordinated. The applicator contact pressure has hitherto been neglected in published data, although it dictates the heat transfer resistance between the applicator and the surface of the bulb and is therefore a major factor influencing the therapeutic effect. A device was therefore developed which indicates the applicator contact pressure continuously during therapy, both optically and acoustically. It renders cryotherapy just as effective as microsurgical methods, with no side-effects.

Ciliary Body↗
PubMed1989

[Cryotherapeutic possibilities in the treatment of corneal burns with acid in an animal experiment. II. Histochemical study].

On 10 experimental animals (20 eyes of bastard rabbits) the authors tested the possibility to influence by cryostimulation the increase of the acid mucopolysaccharide content (glycosaminoglycans or proteoglycans) after damaging the eye with 6.0% = 1.4 N sulphuric acid. Eight corneae were subjected to cryotherapeutic treatment 4-6 hours after corrosion, by the method of contact freezing with a cryoapparatus OKG 2, using a technique which in the first part of the work had a convincing cryostimulating effect: working temperature -70 degrees C, 10 spots with a diameter of 2 mm for 7 seconds placed directly in the cornea surrounding the damaged area. As controls for both groups (corroded and cryotreated and corroded not treated) served four normal intact corneae (two animals as above). Collection of samples of the cornea was made on the 4th and 10th day after corrosion. The corneae were processed by histological methods stained with toluidine and alcian blue. It was revealed that on the 4th as well as 10th day after cryostimulation the acid mucopolysaccharide content was higher than without cryostimulation. On the 10th day after the injury and cryotherapy the acid mucopolysaccharide content was normal. The results were evaluated by Fischer's test. The increase of acid mucopolysaccharides on the cornae was more rapid than at the 1% level of significance, as compared with corneae without cryotherapy. Cryotherapy thus promoted restoration of acid mucopolysaccharides in the corroded corneae.

Animals↗
PubMed1989

[Cryotherapeutic possibilities in the treatment of corneal burns with acid in an animal experiment. I. The length of time required for reepithelialization and clearing of corneal clouding].

The aim of the work was to assess in animal experiments whether it is possible to achieve by a cryostimulation regime a therapeutic effect in standardized corrosion with sulphuric acid. To this end both eyes of 50 experimental animals (bastard rabbits) were corroded with sulphuric acid concentrations of 1.2%-6.0%. On the right eyes of the experimental animals after 4-6 hours following corrosion cryotherapy, using the method of contact freezing, was applied. The authors investigated two cryostimulation regimes: working temperature -70 degrees C, 10 points for 7 seconds on the borderline of the corroded area of the cornea, and working temperature of -160 degrees C, 10 points and four seconds on the limbus of the cornea. As criterium of the therapeutic effect they used the period of reepithelization of the corneal defect and clearing of the corneal turbidity to complete transparency. Statistically significant shortening of the investigated parameters--reepithelization and clearing of the cornea--was observed at the working temperature of -70 degrees C and by using the points at the borderline of the corroded area for cryoapplication.

Animals↗
PubMed1988

[Localization of the freezing front in tissue by the ultrasound-A picture technic in cryotherapy].

The knowledge of the depth of infiltration of the freezing front in the treated tissue represented an essential demand for an optimal cryotherapy (sprayfreezing and contactfreezing). The hitherto used invasive measuring methods are connected with a tissue traumatisation and therefore only applicable in a limited way. On that account the non-invasive ultrasound-A-picture-technique was applied for defining the freezing front extension. Its qualification was represented in vitro (gelatin), in living biological tissue (muscle of rabbit), and on the human eye (cryotherapy of the primary glaucoma). The use of the sonography in the cryotherapy can be recommended for other special medical branches too.

Animals↗
PubMed1984

[Cryoenucleation in malignant melanoma of the choroid].

The works of Zimmermann, Fraunfelder et al. and Migdal offer reasons for postulating atraumatic procedures for the enucleation of malignant melanoma of the choroid. Cryosurgery represents an effective method of blocking the melanoma prior to enucleation in such a manner that an intraoperative dissemination of tumor cells is unlikely. The technology which is at present widely used for this purpose (Fraunfelder et al.) has considerable disadvantages. For examples cryoapplication is only possible with favorable, i.e., peripheral tumor localization, since the cryoapplicator cannot be introduced into the orbit. Therefore, a cup-shaped cryoapplicator chilled by liquid nitrogen has been developed which can be introduced into the orbit. The operating temperature of -196 degrees C causes the half of the eyeball in which the tumor is located to freeze within 100 seconds. Subsequently the applicator is removed and the enucleation is continued in the traditional manner. The technical suitability of this procedure has meanwhile been demonstrated in 12 enucleations.

Choroid Neoplasms↗
PubMed1984

[Results of cryoextraction of dislocated and severely subluxated lenses].

The author reports on the results of cryoextraction of dislocated lenses in 248 cases (74 cases of severe subluxation, 88 lenses dislocated to the middle of the vitreous body, 67 lenses lying on the retina, 19 lenses dislocated into the anterior chamber). In most of the cases the cause was a contusion of the eye. A self-made cryosurgery unit with fiber optic accessories for examining the vitreous body is described. The only serious complication of cryoextraction was retinal detachment (8%). The affected eyes had, as a rule, already suffered considerable damage due to trauma. In most of the cases it was possible to achieve good (1.25-0.5) to reasonable (0.4-0.1) visual acuity. It is argued that removal of the dislocated lens should not be postponed for as long as possible, as has been the practice hitherto; the operation should be performed without delay, while the destruction of the vitreous body is still circumscribed and before any adhesions have appeared between the lens and the retina.

Adolescent↗
PubMed1981

[Nine years' experience of tumor cryotherapy in the cranial region (author's transl)].

The excellent results of more than nine years work in cryosurgery of 1540 cases of tumors of the head are discussed from an ophthalmological and dermatological viewpoint. The majority were basal cell carcinomas of the lids. In the five-year follow-up period 5.5% of basal cell carcinomas and squamous cell carcinomas turned out to be recidives. The paper discusses the techniques of cryosurgical treatment, data from temperature measurements and histological investigations and the possibility of qualitative evaluation of cryodestruction of tumors by means of low-frequency electrical impedance measurements.

Cryosurgery↗
PubMed1980

[Results of cryosurgery for the treatment of vascular nevi and tumors (author's transl)].

Report on experiences of the application of cryotherapy in 187 patients with 200 vascular nevi and angiomas. The fit form of therapy for angiomas is contact-freezing because of simultaneous compression. The cryotherapy of cavernous angiomas in skin and oral mucosa, especially in difficult locations, produces excellent results. In those cases the cryotherapy is the method of choice. In founded indications capillary angiomas of infants could be successfully treated. Port-wine nevi in part are suitable for the application of low temperatures.

Adult↗
PubMed1977

[Patency of the lacrimal ducts after cryotherapy of eyelid tumors].

It is the advantage of cryotherapy of eyelid tumors that it does not destroy the lacrimal points or the lacrimal canaliculi. The patency of these is kept in spite of freezing tempertures near to fluid nitrogen boiling point. To explain this phenomenon, thermoelectrical measurements during, and histological examinations after experimental cryotherapy were performed. Epithelial lesions lasting a few days were noted and the lumen of canaliculi always remained open.

Cryosurgery↗
PubMed1977

[Cryotherapy in basalioma].

The biological basis of cryotherapy of tumours is explained. The enveloped cryosurgical instruments in Dresden were presented. Oculists and dermatologist have treated 200 basal cell epitheliomas by cryotherapy. Good functional and cosmetical results were seen. The time of control completes up to 5 years.

Basal Cell Carcinoma↗
PubMed1976

[Cryotherapy of eyelid and conjunctival tumors].

Report is given of cryobiological principles, technique and results of cryotherapy for eyelid or conjunctival tumors in 181 cases. In the majority of cases they were basaliomas. In all cases the therapy was successful. No eyelid contractions or tear duct stenosis were noted. The follow-up of 4,5 years showed only 2 recidives. Histologically, cryonecrosis showed capillary ectasis with hyperemia.

Basal Cell Carcinoma↗