Das flüssige Silikon in der Amotiochirurgie-Bericht über 90 Fälle

Main Principles of Vitrectomy Using Intraocular Tamponades - A Basic Course in Surgery

This article is intended to clearly present the basic principles for the use of intraocular tamponades in vitreous/retinal surgery in the event of retinal detachment and other pathologies using additional video footage. It examines the various gases, silicone oils and perfluorocarbon liquids with their indications, administration and in particular intraoperative handling including pitfalls and complications. Characteristic animations show the principles of use in surgery in a comprehensible way. The two lead authors dedicate this article to their teacher Prof. Dr. V.-P. Gabel, who in the early 1990s successfully established the first vitrectomy courses for ophthalmologists at Regensburg University Eye Clinic each year. Many colleagues who still work in retinal surgery today first started learning about this segment on these courses. The other coauthors participated under his supervision in annual vitrectomy wet labs run by the German Academy of Ophthalmology.

Incidence and management of elevated intraocular pressure after silicone oil injection

PURPOSE

To determine the incidence and clinical features of chronic elevated intraocular pressure after pars plana vitrectomy and silicone oil injection for complicated retinal detachments, and to evaluate the clinical management of eyes with secondary glaucoma.

METHODS

This was an observational consecutive case series of 450 eyes in 447 patients who were treated with pars plana vitrectomy and silicone oil injection. Patients who developed secondary glaucoma were treated medically with antiglaucoma medications and surgically with glaucoma drainage implants placed in an inferior quadrant. Main outcome measures were intraocular pressure, number of glaucoma medications, surgical success, and complications.

RESULTS

Fifty-one of 450 eyes (11%) developed elevated intraocular pressure after pars plana vitrectomy and silicone oil injection whereas 399 eyes (89%) did not have a rise in intraocular pressure. Of the 51 eyes that developed elevated intraocular pressure, 40 (78%) were treated only with glaucoma medicines. Medical therapy reduced the intraocular pressure from a mean +/- SD of 26 +/- 13.4 mm Hg before treatment to 18 +/- 9.1 mm Hg after medical treatment (P = 0.002). The 11 of 51 eyes (22%) with elevated intraocular pressure that failed medical therapy were treated surgically with Ahmed Glaucoma Valve implantation within 12 months of silicone oil injection. In the surgical group, intraocular pressure was reduced from a mean +/- SD of 44 +/- 11.8 mm Hg before surgery to 14 +/- 4.2 mm Hg at the most recent follow-up after surgery (P < 0.001). The number of antiglaucoma medications was reduced from 3.5 +/- 0.7 before surgery to 1.2 +/- 0.5 at the most recent follow-up after surgery (P < 0.001).

CONCLUSION

Chronic intraocular pressure elevation occurs in a minority (11%) of patients who are treated with silicone oil. Most of these eyes are effectively treated with antiglaucoma medications. Eyes that do not respond to medical therapy may be effectively managed with glaucoma drainage implant placement in an inferior quadrant.

Vitrectomy for traction macular detachment in diabetic retinopathy

BACKGROUND

A small number of eyes with proliferative diabetic retinopathy develop massive central fibrovascular membranes characterized by vitreoretinal tractions along the arcades and optic disk and retinal traction lines extending through the macula. The aim of our study was first to present the results of vitrectomy for removal of these central membranes and second to determine the correlation between preoperative parameters and postoperative visual outcome.

SUBJECTS AND METHODS

We treated 28 eyes with severe central fibrovascular diabetic membranes by a modified bi-manual en bloc excision technique during vitrectomy. Preoperative examination included general status, visual acuity, slit-lamp investigation, binocular funduscopy, ultrasound investigation and visual evoked potentials (VEP). Further, we analyzed intraoperative complications and postoperative anatomic and functional outcomes.

RESULTS

The retinas of 27 eyes with central traction retinal detachments were reattached by surgery. With a minimum of 6 months' follow-up, the macula remained attached in 24 eyes, while the retinas were completely attached in 22 eyes. Preoperative visual acuity was defective light perception to 0.1; an increase in visual acuity to maximal 0.1 was seen in 50% of the patients postoperatively. Preoperative visual acuity of light perception was associated with no functional improvement. Preoperative ultrasound investigation gave information about the real anatomic situation of the retina, especially if funduscopy was not possible. The other preoperative parameters could not predict correctly the functional outcome of vitrectomy in diabetics with severe central fibrovascular membranes because of the damage of the optic nerve and the retina.

CONCLUSIONS

The high rate of anatomical reattachment after vitrectomy in diabetic eyes with severe central fibrovascular membranes is associated with a slight improvement of function; only preoperative visual acuity of hand motions or better was associated with an improvement of function.

Postsurgical hypotony: relationship to fistulization, inflammation, chorioretinal lesions, and the vitreous

Hypotony is a natural occurrence, symptom, and complication of surgical treatment. With more sophisticated and aggressive techniques, postsurgical hypotony recently has been given increased attention as an obstacle to success of surgery for glaucoma and retinal detachment. Whereas two standard deviations below normal pressure (15.9-5.8 = 10.1 mm Hg) can be called hypotonous, most eyes, depending on scleral rigidity, lid pressure, eye rubbing, or corneal or retinal edema, will be symptomatic at < 5 mm Hg. Hypotony can be defined as the low pressure (whether acute, transient, chronic or permanent) which, in an individual eye, leads to functional changes (whether asymptomatic or symptomatic) and structural changes (whether reversible or irreversible). Depending on its duration and degree, postsurgical hypotony produces characteristic tissue changes that often are modified by, but separate from, the tissue changes caused by an underlying disease or its surgical treatment. This review summarizes the situations, variably associated with hypotony, that occur after such interventions as cataract extraction, filtering surgery, cyclodialysis, cyclodestruction, and vitreoretinal surgery, in addition to the reported pathomechanisms of hypotony and its proposed treatments.

Vitrectomy in diabetic patients with a blind fellow eye

Results of pars plana vitrectomy for complications of proliferative diabetic retinopathy were analysed in 32 consecutive patients with a blind fellow eye due to diabetic eye disease. The mean follow-up period was 22.3 months. Only 16% of all eyes examined had received full scatter photocoagulation prior to referral for vitrectomy. Out of 9 eyes with vitreous haemorrhage, 8 improved to a visual acuity of > or = 0.2 postoperatively. Amid 23 eyes which were vitrectomized for advanced traction retinal detachment, only 4 eyes improved to a postoperative visual acuity of > or = 0.02. In this group 12 eyes deteriorated after vitrectomy, 3 eyes progressing to no light perception. The postoperative visual outcome after vitrectomy for traction retinal detachment in this group of diabetics with a blind fellow eye (mean postoperative visual acuity 0.03 +/- 0.05) was significantly worse (p < 0.000) compared to a group of 196 patients with a seeing fellow eye who were vitrectomized for traction retinal detachment at our clinic (mean postoperative visual acuity 0.09 +/- 0.11). Therefore we conclude that traction retinal detachment in this subgroup of patients is a particularly severe presentation of diabetic retinopathy with a guarded functional prognosis after vitrectomy. Our results demonstrate the importance of timely full scatter photocoagulation and early vitrectomy in eyes with progressive fibrovascular proliferation not responding to panretinal photocoagulation. We conclude that especially diabetic patients with a blind fellow eye must be followed closely and assigned to vitrectomy at an earlier stage of their disease in order to improve functional prognosis.

Temporary silicone oil tamponade in the treatment of complicated diabetic retinal detachments

A retrospective study is reported on 132 eyes with retinal detachment, resulting from advanced proliferative diabetic retinopathy, treated using vitrectomy techniques and silicone oil tamponade. Epiretinal surgery was performed using a bimanual technique. Silicone oil was removed in 64 eyes (49%) which regained an improved final vision of 5/200 or better. In 17 eyes (13%), vision was improved but silicone oil could not be removed. It is expected that the function of several of these eyes will eventually deteriorate because of progressive silicone-induced glaucoma. The remaining 51 eyes (38%) were surgical and functional failures.

Silicone oil for the treatment of severe proliferative diabetic retinopathy

Although silicone oil is being used with increasing frequency for proliferative vitreoretinopathy (PVR), few studies have reported on its use for severe forms of proliferative diabetic retinopathy (PDR). Vitreous microsurgery with silicone oil tamponade was performed on 34 patients (37 eyes) with refractory severe neovascular glaucoma and/or recurrent retinal detachment (RD) from PDR that failed to respond to conventional techniques including vitrectomy, membrane peeling, gas tamponade and photocoagulation. With all patients followed a minimum of 6 months (mean, 13 months), anatomic attachment was maintained in 26 (70%) of the eyes. At the last follow-up examination, a final visual acuity of at least 5/200 was found in 9 (24%) of 37 eyes and 9 (35%) of 26 anatomically successful cases. Regression of iris neovascularization occurred in 8 (36%) of 22 eyes with rubeosis and the silicone oil was removed in 3 (8%) eyes. Significant complications included band keratopathy in nine (24%) eyes, corneal decompensation in three (8%) eyes, and recurrent retinal detachment in seven (19%) eyes.

Complications associated with the use of silicone oil in 150 eyes after retina-vitreous surgery

Complicated retinal detachments (RDs) were successfully managed in 150 eyes of 170 consecutive patients by one surgeon (JLF) using silicone oil in conjunction with modern pars plana vitrectomy. Long-term postoperative complications were observed between 6 months and 5 years of follow-up. Cataracts developed in all phakic eyes and all corneas with oil-endothelial touch showed band keratopathy within 6 months. Recurrent detachments were noted in 22% of eyes during silicone oil tamponade and occurred in 13% of eyes after the oil had been removed. Other complications associated with the use of oil for vitreous surgery included pupillary block glaucoma (3%), closure of the inferior iridectomy (14%), fibrous epiretinal and subretinal proliferations (15%), pain (5%), and subconjunctival deposits of oil (3%). Without exception, within a period of 1 year the intraocular silicone oil showed some degree of emulsification, suggesting that the physicochemical characteristics of the oil injected may be an important variable in long-term complications.

The treatment of giant tear detachments using retrohyaloidal perfluorocarbon gases without drainage or vitrectomy

In a pilot study, an expanding perflurocarbon gas was injected into the retrohyaloidal space for treating giant tear detachments. Using the balloon-gas procedure with a single gas injection, a bubble was obtained that was large enough to tamponade a giant tear without prior drainage of subretinal fluid or vitrectomy. The procedure was performed under subconjunctival anesthesia in order to preserve the patient's light perception, the fading of which served as a safeguard against excessive gas injection. The posterior hyaloidal membrane was only attached to the anterior flap of the tear and to the circumference of the retina anterior to the equator. The retrohyaloidal gas injection was not followed by star-fold formation or other evidence of preretinal proliferation. During the follow-up, the detached posterior hyaloidal membrane appeared to have collapsed on the anterior retina in concertina-like folds. Reattachment occurred in four of the five cases; no retina redetached during an average follow-up of 2 years.

Basal iridectomy at 6 o'clock in the aphakic eye treated with silicone oil: prevention of keratopathy and secondary glaucoma

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.

Specular microscopy of the corneal endothelium after liquid silicone injection into the vitreous in complicated retinal detachments

Twenty-one patients were followed up for at least 6 months after pars plana vitrectomy and liquid silicone injection into the vitreous for complicated retinal detachment by means of specular microscopy. In 17 eyes without silicone penetration into the anterior chamber, only insignificant changes were observed. In contrast, in 4 eyes, where a large drop of liquid silicone penetrated into the anterior chamber, the cell densities rapidly decreased to critical values and a marked pleomorphism of large endothelial cells with abnormal intracellular details indicated serious damage of the surviving cells. A characteristic structureless reflecting layer with contourlike lines in some areas of the specular image was a newly observed bizarre change that was caused by the replacement of the anterior chamber fluid by liquid silicone with markedly different optical properties.

Temporary use of intraocular silicone oil in the treatment of complicated retinal detachment

Complicated retinal detachments in 99 eyes were successfully managed by intraocular injections of silicone oil with or without pars plana vitrectomy. The silicone was then subsequently removed after panretinal photocoagulation. Any remaining anterior vitreous cortex near the vitreous base and/or preretinal proliferative tissue causing traction of the retina was also removed by a vitrectome or extracted by a hooked needle after the silicone-fluid exchange had been performed. The preretinal proliferation occurred in some cases even after silicone oil had been removed. Recurrent detachments were discovered in 8 of the 99 eyes and were managed successfully by reinjections of the silicone. Other silicone reinjections were required in two eyes with diabetic retinopathy and two nondiabetic eyes because of frequent rebleeding into the vitreous cavity.

Electroretinographic studies following vitrectomy and intraocular silicone oil injection

Vitrectomy was performed bilaterally in pigmented rabbits and followed by silicone oil injection in one eye only. Electroretinographic studies were performed preoperatively and at selected postoperative intervals. In the early postoperative period both eyes showed an initial reduction in a and b wave amplitudes, followed by a return to baseline values. The amplitudes were symmetrically and equally affected. Sequential studies over a 20-month period showed no deterioration in electroretinographic response in eyes with and without silicone oil injection.

Silicone oil and its influence on electrophysiologic findings

Twenty patients with complicated retinal detachments who were treated with scleral buckling procedures, vitrectomy, and temporary silicone oil filling underwent electrophysiologic tests before and after silicone oil removal. Electroretinographic responses were markedly low or even absent as long as the silicone oil was in the eye but a few days after silicone oil removal the electroretinographic amplitudes had increased in all 20 patients and did not change significantly thereafter. In 12 patients the basic level of the electrooculogram was low as long as the oil was in the eye but was at least twice the previous value in seven patients after oil removal. A light peak of more than 150% occurred in two patients before oil removal and in six after oil removal.

Ultrasonic findings after treatment of retinal detachment by intravitreal silicone instillation

Postoperative A- and B-scan ultrasonography in 55 patients with complicated retinal detachment who had undergone pars plana vitrectomy with intravitreal silicone oil tamponade showed that the position of the retina could be demonstrated. The reproducible phenomena in eyes with clear media indicated that the same characteristics could be used for diagnosis in eyes with opacification of the lens or cornea.