Biomedical subjects
Publications and source records attributed to R Zivojnović.
A new feature has been developed to increase the efficiency of the widely used back-flush needle aspirator. The main feature of the new design is its almost completely nontraumatic effect on the retina, increasing the scope of application of the instrument.
In the aphakic eye, with intact iris diaphragm, silicone oil has frequently caused a pupillary block. In this situation aqueous humour accumulates behind the iris and forces silicone oil through the pupil into the anterior chamber. An iridectomy at the 6 o'clock position can effectively prevent this pupillary block. The iridectomy allows free passage of aqueous to the anterior chamber which remains free of silicone oil. No permanent contact with silicone oil and the cornea is established, and development of keratopathy is prevented. The effect of this iridectomy in 62 eyes with intact iris diaphragm in patients in Rotterdam (35 cases) and Nagoya (27 cases) is demonstrated. Only in 6.5% of the cases was silicone oil present in the anterior chamber at the end of the follow-up period of 7 months.
Eighteen consecutive patients with proliferative vitreoretinopathy following retinal detachment were treated with radical pars-plana vitrectomy and silicone oil injection. At least 6 months follow-up demonstrated fully attached retinas in 12 patients, partly attached retinas in 3 patients and primary failure in 3 patients. The visual fields revealed serious defects in 50% of those patients with attached retinas. The expected complications such as cataract (100%), glaucoma, corneal decompensation and subretinal oil were seen as well, but the complication rate is expected to diminish with newer surgical techniques.
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A penetrating corneal graft was performed in 12 patients for corneal opacification induced by silicone oil. The patients were all aphakic. They had had vitrectomy and silicone oil injection for complicated retinal detachment, often with periretinal proliferation. The average follow-up time was 13.7 months, during which four out of 11 grafts failed (one case was lost to follow-up). One patient developed severe calcific band keratopathy, and three grafts failed from endothelial decompensation. Changes induced by silicone oil include band keratopathy, thinning, and endothelial damage. The indications for keratoplasty for these corneal changes are discussed.
In clinical and in vitro conditions, the effect of intravitreously injected silicone oil upon the electroretinogram and electrooculogram was investigated. The recorded potentials were lower in the eyes with silicone oil compared to those in which the retinas were reattached without silicone. Retinal changes, caused by the previously existing detachment and the operations already performed, are discussed as possible factors responsible for lower values of the recorded potentials. No arguments could be found in favor of silicone retinopathy.
Indications, results, modified techniques and complications in 280 cases treated with fluid silicon are reported. In about 80% of the cases intravitreal silicon injection under binoscopic control was performed according to the principles described by J. Scott. In the most difficult cases a vitrectomy was carried out and silicon was used only as an internal tamponade. In certain situations the retina itself was treated. The new techniques developed for that purpose are discussed. The follow-up period was between six months and four years. An anatomic success was achieved in more than 70% of the cases. Causes of late complications with the first 100 patients who underwent surgery are discussed. Removal of silicon after a certain period appears a real possibility in spite of initial complications.
Indications, results and complications in 90 consecutive cases of intravitreal silicon injection are reported. Intravitreal silicon injection was performed according to the principles described by J. Scott. The patients, mostly cases which were inoperable with standard techniques, underwent surgery in the period between the beginning of 1978 and the end of 1979. The follow-up period was between five months and two years. An anatomic success was achieved in about 70% of the cases. The intraoperative complications were mostly hemorrhages and new retinal tears. Most of the late complications, such as cataract and glaucoma, could be surgically treated. The advantages and disadvantages of this procedure are discussed.
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