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Biomedical subjects

R Rochels

Publications and source records attributed to R Rochels.

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

Scanning electron-microscopic studies of the collagen architecture of the human sclera--normal and pathological findings.

The arrangement of the collagen fibrils of the human sclera was analyzed in the region of the limbus cornea, the corneoscleral trabeculum, at the zone of muscle insertion and at defined areas of the internal and external surface of the sclera. Adult eyes with no apparent pathological alterations and the sclera of a patient with staphyloma were examined by scanning electron microscopy. The investigations were performed to describe regularities in the collagen architecture in normal and pathologically altered eyes to understand pathomorphologic and pathophysiologic changes in scleral diseases.

Aged↗
PubMed1996

SEM studies of the collagen architecture of the human lamina cribrosa: normal and pathological findings.

The arrangement of the collagen fibrils of the lamina cribrosa was analyzed by using scanning electron microscopy with clinical regard to morphological alterations in cases of glaucoma at different stages. Adult eyes with no apparent pathological changes and specimens from patients with absolute glaucoma were studied. In the lamina cribrosa of nonpathological eyes the collagen fibrils are arranged circularly around the points of passage of axons and vessels. In specimens from glaucoma patients the characteristic circular alignment of the collagen fibrils around the penetrating axons is generally absent. The collagen fibrils are arranged in coarse bundles, showing no preferred alignment. The present study supports a new hypothesis for glaucoma pathogenesis.

Aged↗
PubMed1996

Circular surgical cyclopexy after extensive traumatic cyclodialysis.

The authors operated on a patient who had bilateral ocular hypotony after severe blunt ocular trauma with subsequent circular cyclodialysis and luxation of the lenses. Because of the specific situation, none of the previously reported procedures could be applied. A new surgical technique was used to circularly refixate the ciliary body ab interno. The method described here is simple and can be recommended as an alternative technique to refixate the ciliary body in all aphakic or pseudophakic eyes with persistent ocular hypotony caused by traumatic or surgically induced cyclodialysis.

Adult↗
PubMed1995

[Emergency therapy of traumatic orbital hematoma with acute visual impairment].

Midfacial injuries, surgery of the orbit or the paranasal sinuses as well as retrobulbar anesthesia can be the cause of a traumatic laceration of the ophthalmic artery and/or its branches prompting an extensive orbital hemorrhage with consecutive blindness. Since the neurosensory retina does not tolerate an ischemia of more than 1-3 hours, therapy has to be emergent: an extensive lateral horizontal canthotomy and vertical cantholysis, and if the hypertony of the globe persists, splitting of the periorbita in the temporal lower lid region are mandatory. The surgical details are presented.

Emergencies↗
PubMed1995

[Sandwich intraocular lens implant: a concept for aphakia correction in children].

BACKGROUND: In the management of congenital cataracts the correction of aphakia is still an unsatisfactorily solved problem. As far as surgical techniques and materials are concerned, the implantation of an IOL seems to be justified even in younger children; but choosing the refractive power of the lens is somewhat difficult regarding the expected growth of the eye. MATERIALS AND METHODS: A new type of IOL is presented as a solution for this problem. Being composed of a PMMA-fashioned optic and haptic it bears a silicone lens which is fastened on top of it. The supporting lens is made of PMMA (polymethylmethacrylate) with a biconvex surface with modified J-loops. The diameter of the optic is 6 mm, the overall diameter is 11 mm. The supplementary lens is made of the same silicone material as used for foldable intraocular lenses. Its diameter is 4.5 mm. This additional component can be removed from the implanted lens so that the needed reduction of refractive power after completed growth of the eye can be performed. The PMMA-fashioned basic component remains in situ just like a conventional posterior chamber lens. The lens was examined using scanning-electron microscopy. Im- and explantation was performed in isolated porcine eyes. RESULTS: The high quality of the lens could be demonstrated using scanning-electron microscopy. The technical feasibility of this concept could be demonstrated on isolated porcine eyes. DISCUSSION: Currently the sandwich lens is being tested in animal experiments. Our special interest is focussed on biocompatibility, formation of secondary cataract, biological reactions in the interface and the possibility of atraumatic explantation of the silicone lens.

Aphakia, Postcataract↗
PubMed1995

[Coronal incision as the surgical approach to the orbits].

The coronal incision of the skin extends from the ipsilateral preauricular region to the other side parallel to the coronal suture. The skin flap can then be mobilized down to nearly the floor of the orbits. We routinely use this incision in the following diseases and surgical procedures of the orbit: (1) osteo- and orbitotomies in premature synostosis of skull bones and craniofacial dysplasias; (2) frontobasal midface traumatology involving the orbit; (3) removal of fronto-ethmoidal mucoceles and tumors with orbital involvement; (4) bilateral medial three-wall and lateral one-wall decompression in Graves' disease; (5) removal of tumors from the upper and medial level of the orbit via a transperiostal incision or an extended supraorbital resection. The major advantages of the coronal incision are the excellent exposure of normal and pathological structures of the (peri-)orbital region and the highly satisfying late cosmetic results.

Craniotomy↗
PubMed1994

[Perspectives in diagnosis and therapy of orbital diseases].

New or prospectively promising developments in diagnostics and therapy of orbital diseases are presented. Essential improvement concerns computerized tomography (finer stratification) and magnetic resonance tomography (specific imaging methods like suppression of the orbital fat signal). Three dimensional reconstruction is particularly useful. Diagnostic of vascular processes is facilitated by color doppler imaging. The Doppler signal is superimposed in color over a conventional gray-scale ultrasound image, thus giving additional information about blood flow in vessels. Application of endonasal surgery, which in ENT has been developed to great perfection, enables different surgical interventions, e.g. extraction of favourably positioned foreign bodies and decompressive procedures in Graves' disease. More precise and less side-effect-producing radiotherapy is permitted by a new procedure in which special plastic tubes are implanted, which tips are positioned as closely as possible to the area to be irradiated. Irradiation commences by insertion of radioactive iridium into these tubes by a computer-controlled injection-device. As a prospect for near future the possibility of endoscopical orbital interventions, e.g. biopsies is to be mentioned.

Brachytherapy↗
PubMed1994

Pterional/Lateral approach to orbital tumors.

The purpose of this article is to detail our experience with an approach to primary pathologic conditions involving the orbit. In 27 patients these included tumors of the lacrimal gland, lymphangiomas, neurinomas, meningiomas, and various cysts of the orbit. Access to these lesions was gained by a lateral pterional approach with osteoclastic or osteoplastic removal of the lateral bony wall/roof of the orbit, and by entering adnexal contents following elevation of the lateral rectus muscle. This approach allowed for complete tumor removal in all patients. The specifics of this approach will be discussed and associated orbital complications will be detailed.

Journal Article↗
PubMed1994

[Functional results after implantation of Array type refractive multifocal intraocular lenses].

A prospective study is under way to assess the performance of refractive multifocal intraocular lenses (IOL) of the "Array" type. The results obtained in 35 patients who have been followed up for at least 3 months are reported. In the course of the study it is planned that 100 IOL of this type be implanted. The following parameters were evaluated: distance visual acuity, near visual acuity (Nieden, Jaeger), contrast sensitivity (Regan charts 96%, 50%, 25%, 11%), glare (Brightness Acuity Tester, BAT) for distance and near visual acuity, and other Regan charts. In 28% of the patients the best distance visual acuity was achieved without any correction, while 13% (Nieden 1-3) and 47% (Jaeger 1-3) did not need any correction for their best close visual acuity. Overall, an average correction of +2.6 D was necessary for best near-visual acuity. The average uncorrected distance visual acuity was 0.7, and the average best corrected distance visual acuity was 1.0. In contrast sensitivity testing with the 50% Regan chart, visual acuity decreased by an average of 16% compared with the 96% chart. Even lower contrast reduced visual acuity by 33% (25% chart) and 81% (11% chart) compared with the 96% chart. When glare was tested with BAT at the "high" position the average visual acuity against that without BAT decreased by 19% for the 96% chart, by 25% for the 50% chart, by 45% for the 25% chart and by 82% for the 11% chart. The Array-type IOL allows good distance and near visual acuity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Ophthalmologic symptoms in meningioma of the orbits and in the anterior and medial cranial fossa].

UNLABELLED: The records of 182 patients treated for a meningioma of the orbit or the periorbital region between 1971 and 1989 were analyzed. PATIENTS: There were 138 women (76%) and 44 men (24%). Twenty patients had a meningioma of the optic nerve sheath, 78 patients a meningioma involving the sphenoid wing, 29 a meningioma within the sella region, 36 patients a meningioma of the anterior cranial fossa and 19 patients a meningioma of the medial cranial fossa. RESULTS: As an initial symptom 53% complained of decreased vision, 25% of headaches and 16% had exophthalmos. At the first ocular examination visual acuity was decreased below 0.1 in 22%. In 58 eyes we found papilledema and in 60 eyes optic atrophy. Other manifestations were visual field defects, ocular motility deficits in 20%. Histologically the meningiomas were most commonly of the endotheliomatous type (72%). In 23% of the patients, the tumor recurred, which manifested itself in a third by ocular symptoms.

Adult↗
PubMed1993

Orbital involvement in Wegener's granulomatosis.

Orbital granulomas may complicate the course of Wegener's granulomatosis (WG). Granulomas that grow and compress the optic nerve may lead to blindness. Careful magnetic resonance imaging (MRI) is recommended for early detection and follow-up of intraorbital granulomas. Sufficient systemic immunosuppressive treatment should be given as usual for Wegener's granulomatosis. In order to preserve vision orbital decompression may be necessary in rapidly progressive pseudotumor of the orbit.

Adult↗
PubMed1993

[Excentric lentiglobus posterior].

BACKGROUND: The posterior lentiglobe is a rare anomaly of the lens shape. Two cases of excentric protuberance of the posterior capsule are presented. To our knowledge, only one description of a similar case exists so far. PATIENTS: An eight-year-old girl (diagnosis by routine examination, V.A. 20/20) and a six-year-old boy (V. A. 20/200, esotropia) are presented. Apart from a persistent hyperplastic primary vitreous and a posterior pole cataract a vitreous cyst adherent to the posterior surface of the lens has to be considered as differential diagnosis. The etiology remains unclear. CONCLUSION: In excentric posterior lengtiglobe a good vision is possible. However, if visual acuity is impaired by posterior pole opacity or distortion of the spherical surface, removal of the lens followed by optical correction (contact lens, intraocular lens) of aphakia should be performed.

Cataract Extraction↗
PubMed1993

Bilateral severe keratomalacia after acute pancreatitis.

A rare bilateral severe keratomalacia occurred in an emaciated alcoholic, 57-year-old white man with acute necrotic pancreatitis. The patient had a 10-year history of chronic alcoholism. Laboratory and clinical findings were consistent with the diagnosis of a fat malabsorptive and malnutrition syndrome secondary to chronic and acute alcoholic pancreatitis. Visual acuity of both eyes was limited to light perception. Bilateral corneal necrosis after acute pancreatitis has not previously been reported.

Acute Disease↗
PubMed1993

[Mechanism of the formation of orbital floor fractures. Holographic interferometry studies].

To date, it has not been possible to answer the question of whether in the classic blow-out fracture the orbital floor is fractured by hydraulic force exerted by the orbital contents or by force transmission within the bony structures of the skull. The aim of our investigation was therefore to reveal the nature of orbital deformation mediated solely by the bone. In holographic interferometry the holographic image of the unstrained object is superimposed on the image of the same object after deformation. The resulting image of the object contains a pattern of interference lines representing the extent of the deformation. This image can be visualized on a TV screen after digital processing of a picture registered by a video camera. This method was used to analyze the deformation of the bony orbit by contact force applied to several points along the orbital rim (each application consisting of 1 N) and by strain distributed evenly upon the orbital rim of the human skull. In all cases maximal deformation occurred in the medial part of the orbital floor no matter where the stress was applied. This finding coincides with the fact that the majority of clinically diagnosed fractures are found in this area. In conclusion, force transmission within the bone is considered as being one determining factor for occurrence of orbital floor fractures.

Biomechanical Phenomena↗
PubMed1993

[HLA typing in high risk keratoplasty].

UNLABELLED: Improved microsurgical techniques and better immunosuppressive treatment have led to an increase in the number of corneal transplantations. However, graft rejection due to a disparity between donor and recipient major histocompatibility antigens remains the major complication. The risk of graft rejection is further increased in patients with vascularized graft beds and in presensitized persons. Well-designed experimental studies and clinical experience have clearly shown the importance of class-I-antigens. However, class-II antigens have not yet been studied to the same extent. METHODS: Multiorgan donors and corneal graft recipients were HLA typed using the lymphocytotoxicity test previously described by Terasaki. The recipients were typed retrospectively. Cadaver corneal graft donors were typed using a novel HLA typing technique on retinal pigment epithelial cells, as previously described by us. Postoperatively, all recipients were routinely examined for rejection over a period of 2 years. RESULTS: Graft rejection was observed in 25% of the 133 high-risk patients. Of the 13 class-I-typed patients who showed a rejection 9 persons had two or more major histocompatibility mismatches. Of the 12 patients without rejection problems only 5 had two or more HLA class-I-mismatches. Of the patients with one or two matches at the HLA-DR locus there were only 4 out of 9 patients with at least one graft rejection; 5 out of 6 patients showed no signs of rejection. CONCLUSIONS: Mismatches at either class-I- or class-II- gene loci lead to a higher frequency in corneal graft rejection. Apart from the major histocompatibility mismatches, other factors also influence graft rejection, such as the distance between the corneal transplant and corneal vessels, presensitization, and the indication for corneal grafting. If we are to define the factors influencing graft rejection better and further increase our knowledge on the role the major histocompatibility antigens play in corneal graft rejection in a larger patient group, then cooperation with other transplantation centers will be required.

Graft Rejection↗
PubMed1992

Aplasia of the retinal vessels combined with optic nerve hypoplasia, neonatal epileptic seizures, and lactic acidosis due to mitochondrial complex I deficiency.

A newborn male with mitochondrial complex I deficiency suffered from neonatal epileptic seizures, which later developed into infantile spasms. The infant was blind due to aplasia of the retinal vessels and hypoplasia of the optic nerve. There was congenital lactic acidosis, which persisted in later life. The boy was microcephalic and retarded. Muscular hypotonia later shifted to spasticity. Succinic acid was increased in urine. We assume that the aplasia of the retinal vessels is due to damage of the retinal ganglion cells caused by the mitochondrial disease in the first 3 to 4 months of pregnancy.

Acidosis, Lactic↗