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Biomedical subjects

C Zöllner

Publications and source records attributed to C Zöllner.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Polyglactin 910 (Vicryl) net in myringoplasty. An animal experiment and clinical study].

According to studies by Dociu (1978), the resorption of Vicryl sutures causes only a slight foreign-body reaction in the back musculature of rats. Similarly, in experimental studies by Bowald et al. (1978) Vicryl mesh is reported to be an excellent material for use in the reconstruction of arteries; the chief virtue attributed to it is that it promotes cell proliferation during the healing process, and so promotes the growth of new arterial walls. Stimulated by Dociu's and Bowald's favourable results, we decided to study the influence of an impregnated, and hence stiffer, Vicryl mesh on the outcome of myringoplasties. Myringoplasties were performed on both ears of 15 cats. One ear drum of each cat was reconstructed with fascia and Vicryl mesh, the other (= control) ear drum with fascia only. In addition, myringoplasties with autologous fascia and Vicryl mesh were performed on 18 patients. The absorption of Vicryl mesh results in a temporary but pronounced foreign-body reaction. In consequence, the tympanic membrane temporarily thickens and is thoroughly vasculated. According to our findings Vicryl mesh does not promote the growth of a new tympanic membrane. In our patients we noticed pulpy swelling of the fascia after myringoplastic surgery with fascia and Vicryl mesh. From the above we conclude that Vicryl mesh is not suitable for splintage in myringoplastic surgery.

Animals↗
PubMed1986

[Treatment of stenoses of the laryngotracheal junction and the cervical trachea].

In the past 20 years we have operated on 187 patients for tracheal stenoses. Dilatation, tracheopexy with ring support, sleeve resection, and the gutter procedure are described. In recent years we have replaced open treatment of the tracheal gutter with our closed method. After expanding the posterior wall, the anterior tracheal wall is closed with a myocutaneous island flap, rib cartilage or a myomucosal flap. The merits of the different methods are discussed. Dilatation of the trachea and reconstruction of the anterior tracheal wall over a silicone tube in a one stage procedure creates a sturdy trachea, which is better able to resist scar contracture and pressure from the soft parts of the neck than an open U-shaped gutter. The number of operations and days of treatment per patient are materially reduced by the closed method.

Adolescent↗
PubMed1986

How useful is tricalcium phosphate ceramic in middle ear surgery?

In our experiments on the hypotympanum of the pig, resorbable porous tricalcium phosphate ceramic has proved to be serviceable for reducing radical mastoidectomy cavities and as a substitute for osseous walls. For our initial clinical trials with porous tricalcium phosphate ceramic in middle ear surgery, we had implants made especially for the purposes of replacing osseous walls and reducing radical mastoidectomy cavities. When implants have been used to replace osseous walls, insufficient ventilation of the tympanic cavity has frequently coincided with complications in the covering between implant and auditory canal. Follow-up operations have afforded opportunities for histologic examination of fifteen implants, which served as wall replacements for nine to thirty months. There were only the slightest traces of resorption and replacement by bone. In contrast with our findings on the replacement of walls with ceramic implants, postoperative observation for periods of up to four years has shown that granules of porous tricalcium phosphate ceramic are well suited to reducing radical mastoidectomy cavities.

Animals↗
PubMed1985

The growth rate of acoustic neuromas: a report of three cases.

Until the present time, only a few CT air-cisternographic studies have been done to define the growth rate of acoustic neuromas. By using this method of study, we were able to observe a slow growth rate fo acoustic neuromas in a 41- and a 50-year-old woman over periods of 6-10 months. In contrast, we were unable to find any increase in tumor size during a period of 22 months in a 70-year-old woman.

Adult↗
PubMed1985

[Aluminum oxide ceramic implants (Tübigen type) in middle ear surgery. Report of clinical experiences].

Since 1980 we have used Tübingen middle ear implants of aluminum oxide in some reconstructions of the ossicular chain. So far such implants have been inserted in 129 operations on 106 patients. Follow-up examinations have been performed on 108 ears (91 patients). Post-operative observation periods have varied from 6 to 46 months, with an average duration of 22 months. In the last two years, since observing the first extrusions and imminent extrusions of implants, we have begun inserting a small autologous cartilage-perichondrium disk between implant and eardrum. Follow-up examinations have shown that insertion of cartilage lowers the rates of extrusion and imminent extrusion. It should be noted, however, that the average observation period for implants with cartilage has been somewhat shorter than for those without cartilage. Good audiometric results have been obtained with Al2O3-ceramic implants. Moreover, insertion of a cartilage-perichondrium disk demonstrably contributes to an improvement of audiometric results. As our clinical study shows, an Al2O3-ceramic implant is quite suitable for reconstructive surgery of the ossicular chain when an alloplastic implant is needed. At the same time we strongly advise insertion of a cartilage-perichondrium disk between the eardrum and the implant.

Aluminum↗
PubMed1984

Neuro-otological findings in patients with small acoustic neuromas.

The method of choice for the diagnosis of even the smallest acoustic neuromas is CT gas cisternography. Lumbar puncture and gas insufflation, however, is an intervention demanding strict indication. Neuro-otological examinations should lead to this indication. The aim of this paper is to demonstrate neuro-otological findings on 19 patients presenting small acoustic neuromas. These neuro-otological findings are not necessarily comparable to earlier reports in the literature dealing with mainly larger tumours at a time when early diagnosis was not so advanced.

Adult↗
PubMed1984

[Tracheopexy with support frames. An experimental and clinical study].

The use of acrylic frames to support a weak trachea has been successful in 62,9% of the treated cases (in 22 of 35 operations). The use of ceramic frames has been successful in 92,3% of the cases (in 12 of 13 operations). On the basis of experimental studies, we reconstructed in this manner two rigid stenoses of the trachea by a two-stage method. The first stage consists in expanding the stenosis by means of an endotracheal support of silicone rubber tube; the second stage, in suturing ceramic frames to the trachea. Both operations by this method have been successful. Our methods and results are discussed.

Adult↗
PubMed1983

[Differential diagnostic problems in cerebellopontile angle tumors? A case report].

A patient, suffering from otosclerosis of the right ear, was stapedectomized in 1977. Due to bleeding into the oval window during surgery, a persistent deficit of inner ear performance occurred, causing vertigo and hearing loss of high frequencies, in the right ear. As vertigo increased over the years, the patient underwent extensive otological and neurological examinations without result. Because of anamnestic data all interest was focussed on the right ear, and even gas cisternography was performed on the right side only. Due to a left-side sudden hearing loss, the patient came to the Freiburg ENT Hospital in 1981. ERA examinations and, finally, gas cisternography revealed a tumour--meanwhile confirmed by surgery (acoustic neurinoma)--of the left cerebello-pontine angle. As a consequence of this it must be pointed out that in all cases of unilateral or bilateral loss of hearing of the inner ear and vertigo of unclear etiology, ERA investigations and bilateral gas cisternography should be performed.

Audiometry↗
PubMed1983

[Obliteration of the mastoid cavity with porous tricalcium phosphate ceramic. Results 12 and 18 months after ceramic implantation in the hypotympanon of the pig].

The paper reports on the obliteration of mastoid cavities with resorbable tricalcium phosphate ceramic. As a model, we chose the pneumatic air cell system of the pig's hypotympanon, which resembles the human mastoid. At the time of surgery, the specimens were 10-12 weeks old. In a first group the cells of the hypotympanon were totally removed and the operation cavity was obliterated with adjacent layers of porous tricalcium phosphate ceramic. In a second group of specimens the air cell system was partly removed, leaving the apical part of the hypotympanon intact; the operation cavity was obliterated again with porous tricalcium phosphate ceramic. After 12 and 18 months survival the hypotympanons were removed and prepared for histological investigations. Those ceramic plates, lying close to the bony shell were strongly resolved and replaced by new bone. Other ceramic plates, however, especially those in the center of the implant, showed few signs of resorption and bony remodelling. Inside the ceramic implant there was hardly connective tissue. The space between the still unsolved ceramic plates was filled up with new bony tissue. This bone was partly structured and adjoined directly to the ceramic. The ceramic was integrated into the new bony tissue without any sign of an inflammation.

Animals↗
PubMed1983

[Resorbable, porous tricalcium phosphate ceramic in middle ear surgery. Initial clinical results].

In our experimental study in the pig we could demonstrate that resorbable, porous tricalcium phosphate ceramic material is suitable for an obliteration of mastoid cavities (respectively the hypotympanon of the pig) or for the reconstruction of bony wall. To examine this material in a clinical study for middle-ear surgery, we chose 2 mm thick ceramic plates and segments of truncated cones. With the aid of a diamond drill and irrigation this ceramic can be treated easily. In 25 middle ears, the following reconstructive surgeries were performed with these ceramic implants: in 22 cases a partial replacement of the lateral attic wall, in one case a replacement of the total lateral attic wall, in one case a reconstruction of the canal wall after radical mastoidectomy, and in one case an obliteration of the mastoid cavity. These 25 ears have been followed up for 2-11 months with an average of 7,1 months. In 19 cases the implants showed no sign of any complication. In four cases, however, a dehiscence of the skinny covering (outer ear canal) was observed during the post-operative healing period. In one case this dehiscence closed spontaneously, in the other case we recovered the implant by surgery. In one patient we had to remove the implant, in another one the implant is uncovered and still under observation. An inflammation of the implant bed occurred once. One implant sank down into the middle ear cavity.

Animals↗
PubMed1982

[Brain stem audiometry and metrizamide-meatocisternography in diagnosis of small neurinomas of the acoustic nerve (author's transl)].

Reviewing the newest literature, an acoustic neuroma can be detected in 96% of the cases, employing brainstem audiometry. The present study aims to answer the question how good small acoustic neuromas can be detected using this method. Fifty patients with an asymmetric hearing loss, with unilateral caloric deficit and short lasting periods of dizziness when changing position were investigated. Brainstem audiometry as well as metrizamide-meatocisternography were carried out. Thus we were able to detect seven small acoustic neuromas; only one tumor could not be detected with the brainstem audiometry. The findings will be shown and discussed.

Adult↗
PubMed1982

[Are porous tricalcium phosphate ceramics suited for the replacement of bony walls in ear surgery? An animal experiment study of the hypotympanum of the domestic swine].

The purpose of this study was to examine the possibility of a partially or totally posterior canal and lateral attic wall reconstruction with a more stable and therefore less porous tricalcium phosphate ceramic plate (S8). The hypotympanon of 4 pigs was drilled out, leaving the bony shell intact. In the middle part of this cavity a 2 mm thick S8-ceramic plate was placed horizontally. The hypotympanon of further 11 pigs was drilled out and obliterated with a more porous tricalcium phosphate ceramic (S5). Additionally, a single S8 ceramic plate served as a wall to the cavum tympani. 1 to 18 months after operation the pigs were sacrificed; sections of the hypotympanon were investigated with light microscopy. After few weeks, the S8-ceramic plate was covered by granulation tissue and epithelium on the tympanic side. After three months newly formed bony tissue could be observed between the peripheral parts of the S8-ceramic plate and the tympanic epithelium. After six months both sides of the S8-ceramic plate were completely covered by new bone; moreover this bone is covered by the mucosa on the tympanic side. At this time the S8-ceramic plate has a tight bony contact to the shell of the hypotympanon and bone growth can be observed in the macropores of this plate. The bony layer on the tympanic side of the S8-ceramic plate remained slim, there was no exophytic growth after 12 months. After 18 months the S8-ceramic plate shows distinct signs of resorption and bony replacement. However, in comparison to the S5-ceramic this occurs slower and later.

Animals↗
PubMed1981

[Can the differential diagnosis cochlear-retrocochlear disorder be improved using the brain stem potentials with changing stimulus repetition rates? (author's transl)].

The influence of click stimuli delivered at different repetition rates upon the brainstem potentials was studied by various investigators some years ago. Until now only few reports are available using this technique in recognizing retrocochlear disorders. Moreover these studies yield contradictory results. Therefore the effect of changing stimulus repetition rates in patients with cochlear lesions as well as retrocochlear disorders was studied, when registering the brainstem potentials. Results show that regarding the three parameters amplitude of potential V, latency of potential V and latency difference of potential I-V, a similar influence of a changing stimulus repetition rate could be observed in normal hearing persons and patients with cochlear lesions. However, in some cases with retrocochlear disorders (acoustic neuroma) the technique demonstrated significantly different changes, regarding the above mentioned parameters. The technique thus proved to be sometimes a useful tool in the differential diagnosis of cochlear and retrocochlear lesions.

Audiometry, Evoked Response↗
PubMed1981

[Criteria for the differential diagnosis of cochlear-retrocochlear disorders with brain stem audiometry (author's transl)].

Brain stem audiometry turned out to be a useful tool in the differential diagnosis of cochlear-retrocochlear damage. Reviewing the literature of recent years it becomes clear that various criteria are used to distinguish such lesions when interpreting the brain stem potentials. The most frequently used parameters are: 1. ipsilateral latency of potential V as compared to mean of normal population; 2. difference of latency of potential V of ipsi- and contralateral side; 3. ipsilateral latency difference potentials I -- V as compared to mean of normal population; 4. difference of latency difference potentials I -- V of ipsi- and contralateral side. Evaluating the registrations of brain stem potentials of 50 patients with uni- or bilateral cochlear lesions these parameters had a different degree of liability. Comparing latency differences of potentials I -- V of ipsi- and contralateral sides was the safest method to avoid a false positive diagnosis. It is discussed why this parameter should be the most suitable in the distinction of cochlear and retrocochlear lesions.

Acoustic Stimulation↗
PubMed1981

[Obliteration of the mastoid air cell system with porous tricalcium phosphate ceramic. An animal experiment of the bulla tympanica of the pig (author's transl)].

The paper reports on an animal experiment on the obliteration of mastoid cavities with tricalcium phosphate ceramic. The pneumatic air cell system of the bulla tympanica of pigs of 11-12 weeks of age was totally removed in one group of animals and partially removed in the second group. In this second group, apical part of the bulla was left intact. The operation cavity was then obliterated with adjacent layers of porous tricalcium phosphate ceramic. Histological sections wee evaluated for both groups of animals after survival time of 1, 3 and 6 months. Initially, an ingrowth of granulated tissue between the ceramic layers and into the porous surface can be observed. This dissolves the ceramic material, which is substituted by bony tissue. Pneumatic cells in the apical part of the bulla, which were left intact in the second group of animals, do not obliterate after the air supply has been cut off by sealing the basal part. Cystic cavities remain which contain a serous exudate. After 6 months, the mucous membrane of such cells shows signs of "sclerosis". Formation of spongy bony tissue with marrow spaces can be seen in most of the apical areas of the growing bulla. There is no formation of air-containing cells. It appears from our preliminary results obtained from animal experiments that porous tricalcium phosphate ceramic may be a suitable material for the obliteration of mastoid cavities.

Animals↗
PubMed1980

[A case report of macroglossia following tongue bite (author's transl)].

A variety of congenital or acquired diseases may cause macroglossia. We report the case study of a 25 year old patient with Down's Syndrome who developed macroglossia after injury to the tongue from a self-inflicted bite. Conservative therapy for one month through wound revision, antibiotics and antiphlogistics was only successful in controlling infection but failed to prevent the occurrence of a massive macroglossia. This latter problem could only be managed through reconstructive surgery. Histological studies of tissue taken from the tongue revealed the presence of an interstitial edema containing protein, but without evidence for mucopolysaccharides, glycogen or amyloid. A network of dilated blood and lymphatic vessels with partial stenoses caused by organized thrombosis and proliferation of endothelial cells could be observed, suggesting the presence of a congenital lymphangio-hemangioma. However, we believe that these findings were the result of the obliteration of lymphatic and blood vessels through trauma and inflammation to produce the patient's macroglossia.

Adult↗