Biomedical subjects
Publications and source records attributed to R Rochels.
A case of bilateral microphthalmos with orbital cysts is presented with clinical, echographic, CT and genetical findings. An incomplete trisomy 22 is shown as the likewise cause of the malformation. No further symptoms known to be part of the cat-eye-syndrome could be detected.
BACKGROUND: Granulomas of the orbit can complicate Wegener's granulomatosis (WG). If they compress the optic nerve, blindness of one or both eyes may result. Therefore, early detection and sufficient treatment are important. MATERIAL AND METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) of the orbit and CNS were performed in patients suffering from WG and orbital granulomas (n = 6). The patients were seen interdisciplinary by internists, ENT-specialists, radiologists and ophthalmologists. RESULTS: 12 out of 121 biopsy proven WG-patients showed orbital granulomas during their disease process. Granulomas of the orbit could be best visualized by MRI. However, MRI and CT taken together were most informative. 6 patients with orbital granulomas are presented as case reports, in four of them WG lead to blindness of one eye. The course of orbital granulomas may be chronic progressive or acutely fulminant. Therapy of first choice is a high dosage, long-term immunosuppression with cyclophosphamide and prednisolone. CONCLUSIONS: The detection of orbital granulomas in WG is most successful using CT and MRI. In addition to that, the analysis of visual acuity and visual field are the most important parameters in the detection and follow-up of orbital granulomas. A high dosage, long-term immunosuppression is the treatment of first choice, but in rapidly progressive cases an early decompression of the orbit has to be discussed additionally.
Among the accepted advantages of general anesthesia in ophthalmic surgery is improved control of intraocular pressure (IOP). Although standard textbooks advocate deliberate arterial hypotension to facilitate intraocular surgery by reducing IOP, scientific proof of such an effect is lacking. The authors investigated effects of induced arterial hypotension on IOP in an anesthetized porcine model. Forty-two piglets were anesthetized with piritramide, were placed in the prone position, and had the anterior chamber of one eye punctured with a small Teflon cannula to measure IOP. Six pigs were used in a pilot study to establish dose-response relationships for the hypotensive agents; 36 pigs were randomly allocated to one of three groups (n = 12) to receive nitroprusside, adenosine, or isoflurane to reduce mean arterial pressure (MAP) by 50%. Measurements were made after initial stabilization of hemodynamic variables and IOP (control), when a stable MAP of 0.5x control was maintained for 10 min or longer, and after return of MAP to a posthypotensive steady state. The median of differences between time intervals was analyzed statistically for all variables. Nitroprusside and adenosine produced hyperdynamic hypotension (cardiac index increased); isoflurane-induced hypotension was hypodynamic. Control IOPs were 12.9, 12.5, and 11.1 mmHg in the nitroprusside, adenosine, and isoflurane groups, respectively. Median change in IOP during hypotension was -1.5, +1.5, and 0 mmHg in the nitroprusside, adenosine, and isoflurane groups, respectively. The IOP during adenosine-induced hypotension was significantly higher than that during either nitroprusside- or isoflurane-induced hypotension. Return of MAP to control levels was frequently associated with intraocular rebound hypertension when arterial hypotension had been induced with adenosine or nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)
A new endonasal microsurgical technique for decompression after traumatic optic neuropathy is presented. Compared to the external transethmoidal, the transfrontal or the pterional approach, the main benefit of this method is the superb stereoscopic vision of the medial aspect of the optic canal. The nerve is approached from a 60 degree to 90 degree angle and continuous suction irrigation allows for safe removal of the bony shell. This surgery is done via the endonasal route and therefore has fewer serious complications compared to intracranial, extradural or intradural approaches. Additional trauma due to retraction of the brain is avoided. The anterior ethmoidal cells and the nasofrontal duct remain untouched, avoiding late mucocele formation.
A major precondition for microsurgical removal of an orbital tumor is adequate topographic preparation of the structures involved. Cosmetic aspects also have to be considered. In this regard, the modified surgical approach presented here is superior to the familiar techniques of lateral orbitotomy. The surgical steps are as follows: hemicoronal incision of the skin starting from the superior end of the external ear, extending into the hairy temporo-frontal region, and ending close in front of the hair line. This incision is performed through the periosteum down to the bone, so that the forehead skin flap can be exposed to give complete exposure of the temporal muscle and the entire bony borders of the orbit. Following the osteoplastic removal of the lateral orbital rim and wall, the periorbita is opened and the intraorbital tumor can be removed microsurgically all along the superior, lateral, and inferior regions of the orbit and the muscle cone even in the orbital apex. The postoperative functional and cosmetic results are good.
Eleven patients (6 female, 5 male) with unilateral (6) or bilateral (5) (peri)orbital encephaloceles (nasofrontal in 4 cases, naso-orbital in 3, spheno-orbital in 4), were ophthalmologically examined. All had normal anterior segments, but ipsilateral or bilateral anomalies of the optic nerve head such as coloboma, pits, morning glory syndrome, dysplasia, tilted disk syndrome, hypoplasia, or a persistent hyaloid artery. In regard to the pathogenesis of (peri)orbital encephaloceles associated with optic disk malformations a common clefting defect in the neuroectodermal and neurocristal midline structures of the head is postulated, taking place in the fourth to sixth week of development.
A case of unilateral microphthalmos with orbital cyst is presented. This rare and severe malformation is a non-hereditary disorder. Pathologically it represents a failure in the closure of the embryonic fissure at the 7-14 mm stage of gestation. Staining for neurofilaments permitted the identification of rudimentary optic nerve fibers within the gliomatous cyst wall. Special stains for glial fibrillary acidic protein as well as scanning and transmission electron microscopy were used to characterise the neuroglial cell lining of the cyst wall, and to show microvilli on its inner surface.
The problem in question is the uni- and ipsilateral, acute and irreversible blindness following a minor blunt trauma to the skull without any evidence of a fundus pathology, a fracture in the optic canal or a nerve sheath hematoma. Human cadaver skull bases were examined under static load by means of holographic interferometry. It could be shown that stress lines run in a longitudinal and sagittal direction through the ipsilateral, but transversely through the contralateral optic canal. The complex arrangement of the collagen fibers in the optic nerve sheath and its tough fixation to the bony canal allow only longitudinal-sagittal stress forces to be conducted to the nerve itself, which is consequently stretched and compressed. The transverse direction of the stress lines in the contralateral optic canal, however, are without any mechanical influence on the nerve.
Acoustic microscopy permits a native, nondestructive and artefact-free analysis of the surface of intraocular lenses with regard to manufacturing defects, biologic cellular and membranaceous layers, and signs of degradation. Furthermore, it enables structures below the surface to be evaluated, so that inclusions, pores, microcracks and zones of deformation can be detected. In addition to performance of a one-dimensional, relative intensity profile of the surface and the corresponding pseudo-3D image, the properties of the materials inside the intraocular lens can be characterized by computerized analysis of the reflected ultrasound energy.
Unilateral congenital vitreous cysts (VC) were observed in two young patients. The vitreous was highly liquefied in both. Biomicroscopially, the ball-shaped VC in the first patient was seen to be detached from the surrounding tissues and hence highly mobile. The potato-shaped VC in the second patient was attached to the posterior lens surface by a short, thread-like strand and was therefore only slightly mobile. Partially vascularized prepapillary strands were observed in the patient's fellow eye. Two different pathogenic mechanisms may be postulated, namely (1) that the VC was squeezed or jarred loose from the ciliary body pigment epithelium (first patient), or (2) that the VC resulted from impaired retrogression of the primary vitreous or the hyaloid artery (second patient).
Case report on a 39-year-old man who for five years suffered from a recurrent, firm, crepitant swelling in the medial canthal region after coughing and sneezing. The swelling could be eliminated by digital compression. During a severe bout of sneezing a walnut-sized swelling suddenly occurred which could not be eliminated by compression. Echographic and intraoperative findings confirmed the diagnosis of a large, diverticulous pneumatocele that had compressed the lacrimal sac to such an extent that the entrapped air could not escape. Endoscopy of the nose revealed a wide nasolacrimal ostium, without a Hasner's valve. It was thus possible for air to flow back into the lacrimal drainage system from the nasal cavity.
In this review the indications for ophthalmic sonography are presented along with the variety of diseases of the eye, orbit, its bony walls, and the lacrimal system that can be differentiated and diagnosed by ultrasound. The predictive value, and thus the clinical significance, of sonography are compared with those of other imaging procedures for sensitivity, specificity, radiation exposure, and expense in terms of time and financial resources. The use of prenatal sonography in the detection of ocular and orbital malformations is discussed. Acoustomicroscopy and angiodynography are presented as recent advances in diagnostic sonography, along with examples of application.
Laser-scan microscopy permits the evaluation of surfaces and deeper layers of an object by computer-assisted scanning with a laser beam. The reflected helium-neon or argon laser light is transmitted to a photodetector and after signal processing, to a frame store and a TV monitor. Imaging is realized by synchronous scanning and modulation of light intensity. Laser-scan microscopy revealed a smooth surface of both PMMA and HEMA lenses, whereas tears were detected in folded silicone implants. The physical and chemical homogeneity inside the three different materials was optimal. Compared to scanning electron microscopy, the quality of imaging is not as good with laser-scan microscopy. Nevertheless, one decisive advantage of the latter method is an analysis free of processing and artifacts, which permits a routine control of brand new and folded intraocular lenses.
A total of 284 patients with posterior chamber lenses (Sinskey-Kratz type) implanted in the capsular bag were re-examined on average 14 months after implantation. In 87% optical centration was excellent; 12% showed a minimal displacement exceeding 0.4 mm. In four patients (1%) gross displacement of the lens within the capsular bag was seen, caused by proliferation of residual lens cortex, asymmetric shrinkage of the capsular bag, and perforation of the bag by a lens loop.
76 patients with tumorous swellings of the salivary glands were examined by means of standardized A-scan and B-scan sonography. B-scan echography allowed a differentiation between benign and malignant tumours in all cases. Analysis of the various A-scan criteria (internal structure, reflectivity, borders, consistency and sound attenuation) provided a pathognomonic combination of these criteria for each lesion, enabling further histological diagnosis.
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Standardized sonography and CT scanning have distinct advantages and disadvantages in the evaluation of patients with orbital diseases. Echography provides an efficient screening examination in patients presenting with signs and symptoms of orbital pathology. It allows the detection, localization, measurement and in almost 80% differentiation of orbital lesions. High resolution CT scanning gives an excellent topographic display of masses in the orbit. In visualization of intracranial causes of orbital processes and demonstration of changes in the posterior third of the orbit, in the orbital bones and the periorbital sinuses it is superior to ultrasonography.
A rigid one-piece PMMA anterior chamber lens (Scharf type) had to be removed 30 years after implantation because of diffuse bullous keratopathy and painful secondary glaucoma. Scanning electron microscopy showed the IOL to have a crater-like surface, while the haptics, having been in contact with intraocular tissues, were superficially and deeply eroded. Comparison with two identical anterior chamber lenses which had not been implanted revealed that the changes seen in the removed IOL must have been the result of degradation of the PMMA material.