Slit-lamp fluid-gas exchange and other office procedures following vitreoretinal surgery

The efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment

Purpose

This study was designed to evaluate the efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment.

Methods

We retrospectively reviewed the records of 33 consecutive patients (35 eyes) who underwent fluid-gas exchange treatment for postvitrectomy retinal detachment using the two-needle pars plana approach technique.

Results

The retinal reattachment rate was 80.0% after complete intravitreal gas disappearance following the fluid-gas exchange; the overall success rate was 65.7%. Visual acuity was improved or stable in 80.0% of cases; a two-line or greater vision improvement or a best-corrected visual acuity of 0.4 or better occurred in 62.9% of cases. The success rates for superior retinal detachments and posterior pole retinal detachments were 76.5% and 85.7%, respectively.

Conclusions

Fluid-gas exchange represents a simple and cost-effective alternative outpatient procedure for retinal reattachment without reoperation for the treatment of superior and posterior pole retinal detachments.

Management of postvitrectomy diabetic vitreous hemorrhage with volume homeostatic fluid-fluid exchanger

BACKGROUND

To evaluate the clinical outcome of patients with postvitrectomy diabetic vitreous hemorrhage (PDVH) who underwent vitreous cavity lavage (VL) by volume homeostatic fluid-fluid exchange.

METHODS

We performed a retrospective chart review for 88 eyes of 80 consecutive patients who underwent VL for PDVH. Final best-corrected visual acuity after VL was compared to those before VL. Anatomic outcome, including rate of fundus clear-up, recurrent vitreous hemorrhage, increased intraocular pressure, iris neovacularization and anterior hyaloid fibrovascular proliferation were considered.

RESULTS

Between July 1999 and January 2006, 88 eyes of 80 patients underwent this procedure. Significant visual improvement was observed after VL (2.86 +/- 0.40 logMAR at baseline vs 1.71 +/- 0.97 logMAR at last visit, p < 0.0001). The fundus clear-up rate after VL was achieved in 84 out of 109 times (77.1%). Recurrent vitreous hemorrhage was found in 17 of 88 eyes (19.3%) with the mean interval of 92.6 +/- 126.7 days after VL.

CONCLUSIONS

For patients suffering from postvitrectomy diabetic vitreous hemorrhage, volume homeostatic vitreous cavity lavage can be an alternative method for removing the bloody content in the vitreous cavity efficiently and permitting rapid visual recovery.

Management of post-vitrectomy persistent vitreous hemorrhage in pseudophakic eyes

PURPOSE

To prospectively assess the effect of neodymium:yttrium-aluminum-garnet peripheral capsulotomy on postvitrectomy hemorrhage in diabetic patients with a posterior chamber intraocular lens (IOL) implant and an intact posterior capsule.

DESIGN

Interventional case series.

METHODS

This is a prospective case series, clinical practice.

PATIENTS

Five vitrectomized, diabetic, pseudophakic patients with persistent vitreous cavity hemorrhage remaining after vitrectomy were selected. They all had a posterior chamber IOL implant with an intact posterior capsule. Additionally, they had all undergone laser panretinal photocoagulation in the involved eye in the past for diabetic retinopathy. Neodymium:yttrium-aluminum-garnet laser capsulotomy outside the optic of the IOL was performed in victrectomized diabetic patients to treat the remaining vitreous cavity hemorrhage. Visual acuity, intraocular pressure (IOP), and fundus examination were measured and done immediately after the laser procedure, in 7 days and in approximately 3 months.

RESULTS

The visual acuity was improved at the time of the first follow-up. However, a mild elevation of IOP was noticed in some patients, which was treated with topical dorzolamide. The final visual acuity was dramatically improved, to 20/30 or better, and the IOP was normalized without medication within a few weeks in all five cases. No neovascularization of the iris or elsewhere was noticed in any case.

CONCLUSIONS

Neodymium:yttrium-aluminum-garnet laser peripheral capsulotomy appears to be a safe and effective management procedure in treating postvitrectomy hemorrhage in diabetic patients who have previously undergone cataract surgery with posterior chamber lens implant, intact posterior capsule, and extensive panretinal photocoagulation. The vitreous hemorrhage cleared completely in all five cases.

Experimental study of viscoelastic in the prevention of corneal endothelial desiccation injury from vitreal fluid-air exchange

PURPOSE

To evaluate the usefulness of viscoelastic in protecting the corneal endothelium from desiccation injury associated with fluid-air exchange in a rabbit model.

DESIGN

Experimental study.

METHODS

Rabbit eyes undergoing pars plana lensectomy and vitrectomy were insufflated with either dry or humidified air for 20 minutes following introduction of either Opegan (sodium hyaluronate 1.0%; Santen, Osaka, Japan) or Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%; Alcon, Tokyo, Japan) into the anterior chamber. In two other groups of rabbit eyes, the same procedure was performed without using any viscoelastic agent. Corneas obtained from rabbits undergoing surgery were compared with corneas obtained from rabbits not undergoing surgery. Potential alterations in the corneal endothelium were investigated by scanning electron microscopy, by Phalloidin-FITC staining of actin and by in vitro measurements of corneal permeability for carboxyfluorescein using a diffusion chamber.

RESULTS

Scanning electron microscopy displayed less distortion of corneal endothelium with Opegan and Viscoat compared with the dry air-only exposed corneas. Using humidified air in Opegan and Viscoat coated corneas maintained the normal actin cytoskeleton during fluid-air exchange. Paracellular leakage was much less with Opegan and Viscoat use following infusion of dry air comparing to that of dry air-only group (P =.026 and P =.041). The difference was much more striking following humidified air infusion in Opegan or Viscoat coated corneas comparing to dry air-only infused corneas (P <.002 and P <.002).

CONCLUSIONS

Coating of rabbit corneal endothelium with Opegan or Viscoat before fluid-air exchange largely prevents dry air damage to the endothelium. Infusion of humidified air further protects corneal endothelium during fluid-air exchange in aphakic rabbit eyes.

Management of postvitrectomy diabetic vitreous hemorrhage with tissue plasminogen activator (t-PA) and volume homeostatic fluid-fluid exchanger

The incidence of recurrent vitreous hemorrhage of proliferative diabetic retinopathy following posterior vitrectomy ranges from 29% to 75% in reported series. Fluid-gas exchange and vitreous cavity lavage are the popular methods of treating this kind of recurrent hemorrhage. The fluid-gas exchange cannot offer clear vision immediately after the procedure. To improve the function of the classic vitreous cavity lavage, we designed a volume homeostatic fluid-fluid exchanger - Chen's I/A device. Tissue plasminogen activator (t-PA) is a protease that preferentially converts fibrin-bound plasminogen to the active proteolytic enzyme, plasmin. It has been clinically and experimentally proven effective in lysis of postvitrectomy blood clot and fibrin formation. When the blood clot is formed in the vitreous cavity, intravitreal injection of t-PA can convert plasminogen to plasmin and remove the clot. From July 1999 to January 2000, ten eyes of postvitrectomy diabetic vitreous hemorrhage (PDVH) were collected. In each case, 4 days after intravitreal injection (IVI) of t-PA (30 microg), vitreous cavity lavage was performed with Chen's I/A device. Of these cases, 8 eyes (80%) experienced an immediate clearing of the vitreous cavity. Early complications included anterior hyaloid fibrovascular proliferation (2 eyes) and postoperative intraocular pressure elevation (3 eyes). On the basis of the results of this study, our conclusion is that volume homeostatic vitreous cavity lavage, combined with intravitreal injection of t-PA, is an excellent method for treatment of postvitrectomy diabetic vitreous hemorrhage but, in cases of PDVH with iris rubeosis, the advantage of this procedure is uncertain.

Efficacy of fluid-air exchange for postvitrectomy diabetic vitreous hemorrhage

We reviewed the records of 33 fluid-air exchanges to assess the efficacy of fluid-air exchange in the management of recurrent vitreous cavity hemorrhage after vitrectomy for proliferative diabetic retinopathy. Fluid-air exchange alone was successful in clearing the vitreous cavity in ten of 20 eyes after a mean of 1.5 exchanges per eye. Repeat vitrectomy was required in the remaining ten eyes and anterior hyaloidal fibrovascular proliferation was frequently found. Hemorrhages that occurred in the late postoperative period (more than nine months) appeared more likely to be successfully treated with fluid-air exchange alone. Failure of the initial fluid-air exchange to induce clearing immediately after the procedure appeared to be associated with subsequent exchange failures and need for surgical intervention. Complications from the exchange procedure were infrequent with the development of peripheral retinal detachment in one eye. Our current recommendation for nonclearing recurrent postvitrectomy diabetic vitreous hemorrhage is to perform a fluid-air exchange, provided no other high-risk characteristics are present. If clearing occurs in the immediate postexchange period but rebleeding occurs at a later period, we recommend a second fluid-air exchange. If clearing does not occur in the immediate postexchange period, we recommend proceeding directly to revision of vitrectomy.

Useful adjuncts for vitreoretinal surgery

Many vitreoretinal procedures are performed in offices and hospitals where cost control is important. We describe three useful devices and techniques that facilitate these procedures at minimal expense and often greater convenience. These include an accurate method for localising the pars plana without the use of callipers, an inexpensive, reliable, pressure regulated air pump for fluid-air exchange, and an easy method for intraocular injection of silicone oil through 20 gauge instrumentation without the need for expensive pumps. These procedures and techniques should prove to be useful in the treatment of vitreoretinal disease.

Pars plana vitrectomy and silicone oil injection in proliferative diabetic retinopathy

A retrospective study is reported on 106 eyes with proliferative diabetic retinopathy, treated by vitrectomy and silicone oil injection. Indications were traction detachment in 91 eyes and nonclearing rebleeding in 15 eyes; 31 eyes had previously had vitrectomy. Anatomical success was obtained at the end surgery in 91 eyes, and after a minimum follow-up of 6 months in 68 eyes (64%). Functional results were as follows: satisfactory visual acuity (0.5-0.05) in 23 eyes (22%), ambulatory vision (0.03-CF) in 14 eyes (13%), HM-LP in 54 eyes (51%), and NLP in 15 eyes (14%). The functional results are limited by recurrent detachments due to characteristic reproliferations under the silicone bubble or by ischemic diabetic angiopathy in the attached retina. A positive effect of silicone oil is demonstrated in the reduction of preexisting or postoperatively new iris neovascularization and in preventing postoperative rebleeding.

Repeated fluid-gas exchange for hypotony after vitreoretinal surgery for proliferative vitreoretinopathy

Three patients with prolonged hypotony after vitreoretinal surgery for proliferative vitreoretinopathy were treated with repeated fluid-gas exchanges to maintain intraocular pressure and prevent the development of phthisis bulbi. We performed fluid-gas exchanges solely to treat the hypotony beyond the period when tamponade of retinal breaks was required, and without specific positioning of the bubble. In these patients, the intraocular pressure eventually returned to normal and useful vision was retained.

The physical and surgical aspects of silicone oil in the vitreous cavity

Silicone oil inside the vitreous cavity exerts forces on to the retina as a result of buoyancy, volume displacement, and surface tension. Surface tension rather than viscosity is the key to understanding why the oil seals retinal breaks effectively. The physics of the tamponade was studied quantitatively. Retinal traction can be counteracted by the oil up to a calculated threshold value, depending on the size and shape of the tear, the strength of the surface tension and, most importantly, the distance between the retina and choroid. For a nearly flat retinal hole, the tamponade is very effective. These theoretical results imply straightforward rules for surgery, rules that have been tested in 150 operations. An attempt must be made to fill 100% of the vitreous cavity. Since the air-water boundary has 3 times the surface tension of the water-oil boundary, the most effective procedure is to flatten the retina by means of a fluid-gas exchange and then clamp it in a flat position, implanting the silicone oil. Silicone in the subretinal space or the anterior chamber tends to retract spontaneously, for surface tension causes the smaller bubble to blow up the larger one. Surgical methods are described to make use of it.

Photodisruption of intraocular gas bubbles

During gas-fluid exchange bubbles can form in the vitreous cavity. These bubbles can interfere with visualization of the fundus for retinal examination, photocoagulation, or cryopexy. We used the Nd:YAG laser to eliminate these bubbles in vitro and in two patients.

Major ambulatory surgery of the ophthalmic patient

Ophthalmology, by means of its increased technologic abilities, has been a driving force in the movement toward ambulatory surgery over the past decade. In appropriate situations, nearly any ophthalmic procedure can be done in an outpatient setting. However, even though ophthalmic advances have helped the push toward ambulatory procedures, the future cohesiveness, as well as the superb patient care of ophthalmology, may be threatened in the pressure for cost reductions and efficiency.

Intraoperative use of pure perfluoropropane gas in the management of proliferative vitreoretinopathy

A single-step technique for fluid-gas exchange with pure perfluoropropane gas in proliferative vitreoretinopathy (PVR) is described. The technique was used in 38 eyes of 38 patients. Permanent and total retinal reattachment, with a minimum follow-up of 6 months after gas disappearance, was achieved in 24 eyes (63%). The anatomical success rate was 80.9% (17/21 eyes) in PVR grade C and 41% (7/17 eyes) in PVR grade D. Twenty-two of the successful eyes (92%) underwent a single operation. Thirteen of the successful eyes (54%) obtained final visual acuities of 0.1 or better. Severe increase of intraocular pressure postoperatively, due to overestimation of the intraocular space available for gas expansion, is a potential risk of the technique. This risk should be avoided by means of preoperative evaluation of the vitreous cavity volume with A-scan ultrasonography and intraoperative measurement of the intraocular fluid volume displaced by scleral buckling.

Pneumatic retinopexy. A two-step outpatient operation without conjunctival incision

1,000 consecutive patients operated for retinal detachment were studied prospectively to determine the incidence of complications. Two parts of the operation were responsible for most of the vision-threatening complications: subretinal fluid drainage and the scleral buckle. In an attempt to reduce the complications of retinal detachment surgery, we have utilized a simplified procedure of transconjunctival cryotherapy and intravitreal gas injection with postoperative positioning. This study was limited to detachments with one or more breaks within one clock hour located within the superior eight clock hours of the fundus without signs of proliferative vitreoretinopathy. In a series of 20 consecutive patients, retinal reattachment was initially achieved in all cases. There were two recurrences that were reattached with scleral buckling. The final cure rate for the single pneumatic procedure, with six months follow-up, was 90%. No major complications were observed. This preliminary report suggests that pneumatic retinopexy has the advantages of reduced tissue trauma, no hospitalization, minimal complications, and reduced expense. The major disadvantage is the need for postoperative positioning for five days.