Fluid-gas Exchange Research Articles

Management of Traumatic Hemorrhagic Retinal Detachment With Pars Plana Vitrectomy

Traumatic hemorrhagic retinal detachment may prevent successful visual rehabilitation of eyes with severe posterior segment injury. We managed 19 consecutive cases of traumatic hemorrhagic retinal detachment with pars plana vitrectomy, scleral buckling, and fluid-gas exchange, with or without internal drainage of subretinal hemorrhage. We based our approach on the amount of subretinal hemorrhage present and the location of associated retinal breaks. Internal drainage of subretinal hemorrhage was performed in 16 eyes to allow adequate retinopexy to hemorrhagically elevated retinal breaks (9 eyes), to remove massive subretinal hemorrhage (4 eyes), and to allow intraoperative reattachment when the retina exhibited bullous retinal detachment (3 eyes). Overall, with a minimum of 6 months of follow-up, anatomic reattachment was achieved in 13 (68%) of 19 eyes, and functional success (visual acuity 5/200 or better) was achieved in 6 (32%) of 19 eyes. Anatomic failure resulted from proliferative vitreoretinopathy (4 eyes) and globe atrophy (2 eyes). Drainage of subretinal blood appeared to be beneficial for hemorrhagically elevated retinal tears to allow adequate retinopexy and may help to accomplish long-term anatomic attachment in eyes with massive subretinal hemorrhage or bullous retinal detachment.

Pars Plana Vitrectomy in the Management of Retinal Detachments Associated with Degenerative Retinoschisis

Pars plana vitrectomy and gas-fluid exchange were used to successfully reattach eyes of 12 patients who had symptomatic retinoschisis retinal detachments (RDs) associated with large or posterior outer-layer holes. Visual acuity improved postoperatively in seven (58%) eyes, was unchanged in two (17%) eyes, and decreased in three (25%) eyes. Loss of vision was secondary to a mild posterior subcapsular cataract in one eye and to epiretinal membranes in the other two. In two other eyes, cataracts developed that subsequently required an extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PC 10L) implantation with 20/20 visual acuity in both eyes after cataract surgery. All eyes with a macula-involved RD stabilized or improved in visual acuity. Surgical indications, techniques, and results in the management of these retinoschisis RDs are discussed.

Comparative Study of Different Techniques of Intraocular Gas Tamponade in the Treatment of Retinal Detachment due to Macular Hole (With 1 color plate)

The injection of sulfur hexafluoride (SF6) or perfluoropropane (C3F8) was used as a method of internal tamponade in 43 eyes affected by retinal detachment due to macular hole. The technique of ocular hypotension prior to gas injection varied according to the characteristics of each case, using vitrectomy and SF6 30% in 8 cases (group 1), fluid-gas (SF6) exchange through the pars plana in 10 cases (group 2), paracentesis of the anterior chamber prior to injection of SF6 in 12 cases (group 3) and injection of C3F8 without drainage in 13 cases (group 4). Retinal reattachment was initially achieved in 87 (group 1), 83.3 (group 2), 100 (group 3) and 92.3% (group 4), but 4 recurrences yielded a 6-month follow-up cure of 75 (group 1), 75 (group 2), 91 (group 3) and 84% (group 4). Postoperative complications included proliferative vitreoretinopathy (7%), endophthalmitis (2.3%) and subretinal hemorrhage (2.3%). The use of intraocular gas tamponade appears to be a procedure with an acceptable complication rate in the treatment of retinal detachment due to macular hole. This study suggests the use of paracentesis and SF6 in phakic eyes, C3F8 in aphakic eyes and vitrectomy plus 30% SF6 in eyes with proliferative vitreoretinopathy or vitreoretinal traction adjacent to the macular hole.

Early surgical management in bilateral acute retinal necrosis

One patient with bilateral acute retinal necrosis underwent encircling scleral buckle, vitrectomy, and intravitreal acyclovir on both eyes. This procedure was performed on the right eye while the retina was attached. The retina of the right eye was reattached by performing fluid-gas exchange and modified panretinal photocoagulation when the retina subsequently detached. Soon after the development of retinal detachment in the left eye, the above surgical procedures were performed on the left eye, and the retina was successfully reattached. Bilateral acute retinal necrosis with significant vitreous opacification, which is a devastating ocular disease causing possible blindness in both eyes, requires more aggressive, early surgical management.

The Surgical Management of Giant Retinal Tears with the Cannulated Extrusion Needle

In 18 eyes of 17 patients, we treated retinal detachment caused by a giant retinal tear by unfolding and repositioning the retina with a cannulated extrusion needle. After pars plana vitrectomy, a fluid-gas exchange was performed with the patient in the supine position. Using the cannulated extrusion needle to drain subretinal fluid posterior to the giant retinal tear, the retinal flap was manipulated into the correct anatomic position. With this technique, 18 of 18 eyes with retinal detachment caused by a giant retinal tear were successfully reattached intraoperatively. Although eight of these eyes subsequently redetached and required additional surgical procedures, 16 of 18 eyes remain attached with a mean follow-up of 11 months.

Treatment of Postvitrectomy Fibrin Pupillary Block With Tissue Plasminogen Activator

We injected 25 micrograms of recombinant tissue plasminogen activator into the anterior chamber or the vitreous cavity in seven aphakic patients for pupillary block caused by a complete fibrin pupillary membrane that formed after vitrectomy with fluid-gas exchange. Progressive fibrin deposition resulted in pupillary block by three days after vitrectomy surgery in six patients, and seven days after vitrectomy in one patient. The pupillary block was associated with increased intraocular pressure in six patients. Tissue plasminogen activator was injected via the corneoscleral limbus in five patients and via the pars plana in two patients. In all patients, injection of tissue plasminogen activator resulted in complete fibrinolysis of the fibrin pupillary membrane within four hours, associated with a deepening of the anterior chamber. In the six patients with increased intraocular pressure at the time of tissue plasminogen activator injection, dissolution of the fibrin membrane was associated with a decrease in pressure. In all patients, intraocular pressure had returned to normal by three days after the injection. No complications were associated with the injection.

Posterior Chamber Intraocular Lens Insertion During Pars Plana Lensectomy and Vitrectomy for Complications of Proliferative Diabetic Retinopathy

We inserted posterior chamber lenses into 21 eyes with complications of diabetic retinopathy upon completion of pars plana lensectomy and vitrectomy in a single session. After the original surgery, two eyes developed retinal detachments and underwent vitrectomy revisions with scleral buckling, one eye had a fluid-gas exchange for residual vitreous cavity blood, one eye had supplemental laser treatment, and one eye had intraocular antibiotics for endophthalmitis. Six months later, postoperative vision was better in 16 of the 21 eyes (76%), the same in four eyes (19%), and worse in one eye (5%). In 16 eyes visual acuity was 20/200 or better, and in six eyes it was 20/40 or better postoperatively. Decreased vision was caused by preexisting macular disease; two eyes had corneal edema with iris neovascularization associated with residual retinal detachment. The procedure and lenses were well tolerated and provided good pseudophakic vision.

An Automated Aspirating-Backflush System for Fluid-Gas Exchange and Retinal Manipulation

We have designed a new instrument for use in fluid-gas exchange and retinal manipulation that combines automated aspiration with reflux capabilities. Reflux capability further reduces trauma to the retina when performing procedures using active linear aspiration.

Oculab Tono-Pen, Goldmann Applanation Tonometry, and Pneumatic Tonometry for Intraocular Pressure Assessment in Gas-Filled Eyes

We performed 84 intraocular pressure measurements with the Oculab Tono-Pen, Goldmann applanation tonometer, and pneumatic tonometer in 47 eyes that had undergone pars plana vitrectomy and gas-fluid exchange. Measurements made by using the Tono-Pen were accurate when compared to those made by Goldmann tonometry (mean difference, 0.74 mm Hg). In a subset of eyes with increased intraocular pressure (greater than or equal to 25 mm Hg), the Tono-Pen provided measurements similar to those made by Goldmann applanation tonometry (P greater than .60), with only three of 39 readings (8%) underestimating the Goldmann pressure by more than 3 mm Hg. Pneumatic tonometry significantly underestimated the intraocular pressure in eyes with increased pressure (P less than .001), with 20 of 39 readings (51%) underestimating the Goldmann pressure by 5 mm Hg or more.

Cardiopulmonary responses after spontaneous inhalation of Douglas fir smoke in goats.

In the majority of clinical cases, smoke inhalation results in a self-limited lung injury mostly confined to the airways. In this study, an animal model of inhalation injury was developed that reflected similar pathophysiology. Cardiopulmonary parameters were studied in awake, instrumented goats following spontaneous inhalation of characterized Douglas fir smoke. Peak carboxyhemoglobin levels averaged 37% during a mean exposure time of 33 minutes. All animals survived the 24-hour study period, and showed only transient abnormalities in lung fluid balance and gas exchange, with no change in lung mechanics or plasma eicosanoid (TxB2 and 6-keto-PGF1 alpha) levels. However, extravascular lung water at 24 hours was increased 33%, suggesting the presence of some airway edema and retained secretions. We feel this model fairly represents the majority of clinical smoke inhalation cases. This model is compared to other large animal inhalation injury models producing more severe lung injury.

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.

Pasteurella multocida Endophthalmitis After a Cat Bite

We treated a patient with Pasteurella multocida endophthalmitis associated with a retinal detachment resulting from a cat bite. To our knowledge, endophthalmitis from an animal bite has not been described previously. Organisms were directly inoculated from a perforated wound through the globe. The patient was vigorously treated with intensive systemic antimicrobial chemotherapy and pars plana vitrectomy. The inflammation subsided after repeated vitrectomies. A subsequent retinal detachment was treated with fluid-gas exchange and 360 scleral buckling with a silicone implant. Eight months after surgery the visual acuity was 40/200.

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.

Clinical Applications of Auto Indirect Ophthalmoscopy

A phakic eye that has undergone vitrectomy and gas-fluid exchange produces a real, inverted aerial image anterior to the cornea similar to that produced by a lens for indirect ophthalmoscopy. This image can be used during surgery to perform a variety of maneuvers that would otherwise require a contact prism, high-minus contact lens, or handheld indirect ophthalmoscope lens. Applications of auto indirect ophthalmoscopy include visualization of the retina and vitreous during endophotocoagulation and while using a vitreous cutter.

Management of Fibrin Pupillary-Block Glaucoma After Pars Plana Vitrectomy With Intravitreal Gas Injection

After pars plana vitrectomy and fluid-gas exchange, two patients developed fibrin membranes across the pupillary space resulting in pupillary block and subsequent glaucoma. In one case the angle was closed; in the second case the angle was open because of gas in the anterior chamber. In both cases the argon laser made permanent openings in the fibrin pupillary membrane that relieved the pupillary block.

Treatment of Giant Retinal Tears Combined with Proliferative Vitreoretinopathy

Giant retinal tears with foreshortened and stiffened retina secondary to advanced proliferative vitreoretinopathy (PVR) pose a complex problem for the retinal surgeon. In the past, tractional forces on the retina in these eyes have been counteracted temporarily by retinal sutures, retinal incarceration, or retinal tacks, often combined with fluid-gas exchange in the prone position. These techniques are complex and add multiple additional maneuvers to the surgical procedure. The current report describes the use of a simple, stepwise fluid-gas exchange technique with the patient in the supine position in which the expanding gas bubble traps the edge of the stiffened and foreshortened retina against the pigment epithelium. Long-term counteraction of tractional forces was achieved by the use of intraocular silicone oil. Using this technique, 18 of 19 eyes with giant retinal tears and PVR Grade D1 to D3 could be successfully reattached. Four of these successfully reattached eyes had 360° giant retinal tears. The most common and significant complication in our series was the recurrence of periretinal membranes. All 18 eyes that were initially reattached suffered the recurrence of significant periretinal membranes. Four of those 18 eyes developed recurrent inferior traction detachments one to four months postoperatively.

Ultrasonography as a routine examination before treatment of retinal detachment due to macular hole.

Twelve of 25 patients were treated at the University Eye Clinic in Münster because of retinal detachment due to a macular hole. Partial fluid gas exchange (SF6), vitrectomy and SF6, or vitrectomy and silicone instillation, were used, and the patients were examined both pre- and postoperatively by ultrasonography with particular attention to the situation at the posterior pole. These echographical examinations enabled us to evaluate the following three criteria: staphyloma posticum, stiffness of the retina, and vitreous adhesions. All of these conditions mean that the prognosis will be worse if SF6 gas instillation is used alone. In these cases, a vitrectomy should also be performed or a Klöti-Klemme procedure is useful when stiffness of the retina or staphyloma posticum is present. Preoperative ultrasonography is useful when setting up an adequate therapy plan.

Fluid-gas exchange and photocoagulation after vitrectomy. Indications, technique, and results.

We describe the indications, complications, and results of postvitrectomy fluid-gas exchange and laser photocoagulation for management of complicated vitreoretinal disease. Indications include proliferative vitreoretinopathy, vitreous opacities associated with proliferative diabetic retinopathy, giant retinal tear, recurrent rhegmatogenous retinal detachment, and trauma. Eyes treated with 50% sulfur hexafluoride gas rather than sterile air demonstrated a higher intraocular pressure on the first postexchange day, which was not a significant source of disease. There was no statistically significant difference in retinal reattachment between eyes treated with gas and those treated with air. Fluid-gas exchange in eyes with partial or total retinal detachment resulted in total or partial retinal reattachment, with the macula attached in 82% of cases within the first 48 hours following exchange. Final reattachment rate, with a mean follow-up of 8.9 months (range, six to 36 months), was 55%. In eyes with proliferative vitreoretinopathy, the combination of postoperative argon or krypton laser photocoagulation with fluid-gas exchange was associated with a final reattachment rate of 75%. Postoperative fluid-gas exchange and photocoagulation appear to be safe and effective advances in the treatment of complicated vitreoretinal diseases requiring vitrectomy.

Simultaneous perfusion of air and irrigating solution in the management of traumatic posterior segment injuries.

A technique to perfuse air and infusion fluid simultaneously in the management of severe posterior segment injuries has been developed. The technique requires air infusion through an infusion cannula while fluid is introduced and aspirated by a full-function vitrectomy instrument. This technique can be used in the primary procedure, or in secondary procedures in which the retina has been reattached by a fluid-gas exchange postoperatively.