Reducing Complications in Diabetic Retinal Detachments
A state-of-the-art surgical platform helps this surgeon stay a step ahead of bleeding and iatrogenic breaks.
By Maria H. Berrocal, MD
Since I first began using microincision vitrectomy surgery (MIVS), my thinking about its usefulness has evolved. Today, I use MIVS not only for routine but complex cases, as well (Figure 1). From the start, MIVS was a promising opportunity to use small, self-sealing incisions to reduce surgical trauma, induced astigmatism, inflammation and patient discomfort and foster more rapid visual recovery. Among the most complex cases I see in my practice setting, which has a large diabetic patient population, are traction retinal detachments and combination traction/rhegmatogenous retinal detachments. An impressively long list of factors has increased my use of MIVS in these cases over time.
Compared with earlier years, we now have more rigid 23- and 25-gauge instruments, a wider variety of compatible instruments, brighter light sources, more efficient vitreous removal thanks to specially designed higherspeed cutting probes and fluidics, insertion systems that ease entry into the eye and create more securely sealing incisions, and surgical platform features that enhance surgeon control of several surgical parameters. My surgical platform of choice, the CONSTELLATION® Vision System (Alcon), incorporates all of the latest advancements in these areas. However, in this article, I highlight how I use it in the high-risk eyes of diabetic patients with traction and combination traction/rhegmatogenous retinal detachments.
INDICATIONS, GOALS FOR SURGERY
Surgical intervention becomes necessary when a traction detachment involves, or is threatening to involve, the fovea. In order to reattach the retina, we must remove the fibrovascular tissue that is causing the detachment. Surgery is needed for a combination traction/rhegmatogenous detachment because we have not only the traction component but also the entire retina may be detached and mobile. In order to reattach in these cases, we must remove all of the tractional fibrovascular tissue from all areas of the retina and treat the retinal tears with laser.
REDUCING SCLEROTOMY-RELATED ISSUES
We see the benefits of MIVS from the outset of each case because the smaller sclerotomies and trocars have addressed most of the complications experienced with this aspect of vitrectomy in the past. For example, we no longer have to worry that when we raise IOP to control bleeding, the detached retina might come out of the wound, causing a retinal break. Also, the smaller trocars and cannulas may be less traumatic to the vitreous base. Therefore, postoperative neovascularization of the vitreous base, growing in through the sclerotomies, is maybe less of an issue.
New valved cannulas are now available for the CONSTELLATION® System. The valves prevent fluid from leaving the eye as instruments are being inserted and removed, which contributes to a more stable operative environment.
PREVENTING IATROGENIC BREAKS
As we are all well aware, iatrogenic breaks in the retina are one of the most unfortunate potential complications we face while working in diabetic eyes with retinal detachments. 25-gauge surgery with the CONSTELLATION® System contributes to a reduction in vitreous traction as vitreous is removed. I describe the system's performance as essentially erasing vitreous without significant movement of the underlying retina. The small probe, with the port closer to the tip than in earlier designs, allows us to get under membranes and work very close to the retinal surface in a safe manner. The efficiency at which the probe cuts, even at 5000 cpm, and the control over duty cycle that the system gives us are also major assets for preventing iatrogenic breaks.
Figure 1. Traction and rhegmatogenous retinal detachment before and after 23-gauge surgery.
Figure 2. The 25-gauge ULTRAVIT® High Speed Vitrectomy Probe utilized as a forceps with suction only during surgery performed with the CONSTELLATION® Vision System.
Figure 3. The 25-gauge ULTRAVIT® High Speed Vitrectomy Probe utilized as scissors to segment membranes during surgery with the CONSTELLATION® Vision System.
Figure 4. Reduced vascularity of abnormal tissue in an eye treated with an intravitreal injection of bevacizumab prior to vitrectomy for retinal detachment repair.
Figure 5. Viscodissection helps to lift fibrovascular tissue so it can be removed more easily with the vitrectomy probe.
Figure 6. The CONSTELLATION® Vision System has an embedded 532-nm laser with a curved probe. Here the probe is used with chandelier illumination during scleral depression.
The ability to modify duty cycle to control flow, independent of vacuum and cut rate, allows us to use the vitrectomy probe slowly to shave tissue without it jumping into the probe. Thick blood clots are removed quickly, and membranes can be peeled from blood vessels. The ability to manipulate cuts per minute and duty cycle also expands the utility of the vitrectomy probe. Many tasks that we would have performed with other instruments in the past can be performed with just the probe. We can get under membranes to lift and dissect them. We can use the probe as forceps, scissors or a pick (Figures 2 and 3).
The CONSTELLATION® System also has advanced reflux capabilities, which the surgeon controls with the foot pedal. We can use proportional reflux for membrane dissection and also continuous reflux to “blow” blood and fluid out of the way.
PREVENTING INTRAOPERATIVE BLEEDING
In addition to iatrogenic breaks, intraoperative bleeding is a primary complication in diabetic eyes. One step I often take to reduce the vascularity of the abnormal tissue is to perform an intravitreal injection of bevacizumab within five days prior to vitrectomy (Figure 4).
Also, once inside the eye to treat a diabetic traction detachment, I try to remove all of the vitreous and the blood in the vitreous before addressing the fibrovascular tissue. This improves my view into the eye and allows me to quickly handle any new bleeding that may emerge, before clotting occurs. A strategy I use to prevent bleeding in traction/rhegmatogenous cases is to viscodissect the abnormal tissue (Figure 5). This creates a plane between it and the retina so it can be removed more easily with the vitrectomy probe. Again, as I mentioned previously, I am able to work very close to the retina in this scenario, which was unthinkable with earlier technologies.
The multifunctionality of the CONSTELLATION® System vitrectomy probe, as described above, requires fewer instrument exchanges are typically required, which means fewer undesired changes in IOP. When instruments do need to be moved in and out of the eye, however, or when pressure would typically surge after scleral depression, the system's integrated pressurized infusion with IOP control keeps globe pressure steady within +/– 2 mmHg. Flow sensors in the cassette continuously monitor infusion flow and the system directly compensates for that to maintain the desired overall pressure. In contrast to previous strategies for intraoperative IOP control, this occurs quickly and automatically in real time.
A COMPLETE PACKAGE
In addition to helping us address the main complications associated with vitrectomy in diabetic eyes, the CONSTELLATION® Vision System provides a host of other benefits. It has made setup for procedures quicker than ever, and gives the entire case what I call better overall “flowability.” Everything can be done in a seamless manner. For example, the embedded 532-nm PUREPOINT® laser comes with a flexible tip laser probe, so we can treat the retina all the way to the ora serrata (Figure 6). This was not possible in phakic eyes with previously available straight probes. The intensity of the laser burns is surgeon-controlled with the foot pedal, and we can transition from liquid to gas to laser and so on, in a seamless manner.
The CONSTELLATION® Vision System has dramatically changed the way we tackle these difficult cases.
Dr. Berrocal is a professor of Ophthalmology at the University of Puerto Rico School of Medicine. She practices in San Juan.
CONSTELLATION® Vision System Indications for Use With Laser
Indications for Use: The CONSTELLATION® Vision System is an ophthalmic microsurgical system that is indicated for both anterior segment (i.e., phacoemulsification and removal of cataracts) and posterior segment (i.e., vitreoretinal) ophthalmic surgery.
The PUREPOINT® Laser is indicated for use in photocoagulation of both anterior and posterior segments of the eye including:
• Retinal photocoagulation, panretinal photocoagulation and intravitreal endophotocoagulation of vascular and structural abnormalities of the retina and choroid including: Proliferative and nonproliferative retinopathy (including diabetic); choroidal neovascularization secondary to age-related macular degeneration; retinal tears and detachments; macular edema, retinopathy of prematurity; choroidal neovascularization; leaking microaneurysms.
• Iridotomy/Iridectomy for treatment of chronic/primary open angle glaucoma, acute angle closure glaucoma and refractory glaucoma.
• Trabeculoplasty for treatment of chronic/primary open angle glaucoma and refractory glaucoma.
• And other laser treatments including: internal sclerostomy; lattice degeneration; central and branch retinal vein occlusion; suturelysis; vascular and pigment skin lesions.
Caution: Federal (USA) law restricts this device to sale by, or on the order of, a physician.
Contraindications: Patients with a condition that prevents visualization of target tissue (cloudy cornea, or extreme haze of the aqueous humor of the anterior chamber of vitreous humor) are poor candidates for LIO delivered laser treatments.
Complications: Corneal burns, inflammation, loss of best-corrected visual acuity, loss of visual field and transient elevations in intraocular pressure can occur as a result of ophthalmic laser treatment. Unintentional retinal burns can occur if excessive treatment beam power or duration is used.
Warnings and Precautions:
• The disposables used in conjunction with Alcon instrument products constitute a complete surgical system. Use of disposables and handpieces other than those manufactured by Alcon may affect system performance and create potential hazards.
• Attach only Alcon supplied consumables to console and cassette luer fittings. Do not connect consumables to the patient's intravenous connections.
• Mismatch of consumable components and use of settings not specifically adjusted for a particular combination of consumable components may create a patient hazard.
• Vitreous traction has been known to create retinal tears and retinal detachments.
• The closed loop system of the CONSTELLATION® Vision System that adjusts IOP cannot replace the standard of care in judging IOP intraoperatively. If the surgeon believes that the IOP is not responding to the system settings and is dangerously high, this may represent a system failure. Note: To ensure proper IOP Compensation calibration, place infusion tubing and infusion cannula on a sterile draped tray at mid-cassette level during the priming cycle.
• Leaking sclerotomy may lead to post operative hypotony.
• Back scattered radiation is of low intensity and is not harmful when viewed through a protective filter. All personnel in the treatment room must wear protective eyewear, OD4 or above at 532nm, when the system is in Standby/Ready mode as well as during treatment. The doctor protection filter is an OD greater than 4 at 532nm.
• Important Safety Information: Warnings and Cautions: A complete listing is available in the CONSTELLATION® Vision System Operators Manual. To obtain a copy, please contact Alcon Customer Service.
INFINITI® System Indications for Use
Indication: The INFINITI® Vision System with OZil® IP is indicated for emulsification and removal of cataracts, vitreous aspiration and cutting associated with anterior vitrectomy, and bipolar coagulation.
Caution: Federal (USA) law restricts this device to sale by, or on the order of, a physician.
Warnings: Appropriate use of INFINITI® Vision System parameters and accessories is important for successful procedures. Use of low vacuum limits, low flow rates, low bottle heights, high power settings, extended power usage, power usage during occlusion conditions (beeping tones), failure to sufficiently aspirate viscoelastic prior to using power, excessively tight incisions, and combinations of the above actions may result in significant temperature increases at incision site and inside the eye, and lead to severe thermal eye tissue damage.
Adjusting aspiration rates or vacuum limits above the preset values, or lowering the IV pole below the preset values, may cause chamber shallowing or collapse which may result in patient injury.
When filling handpiece test chamber, if stream of fluid is weak or absent, good fluidics response will be jeopardized. Good clinical practice dictates the testing for adequate irrigation and aspiration flow prior to entering the eye.
Ensure that tubings are not occluded or pinched during any phase of operation.
The consumables used in conjunction with Alcon instrument products constitute a complete surgical system. Use of consumables and handpieces other than those manufactured by Alcon may affect system performance and create potential hazards.
AEs/Complications: Use of the NeoSoniX®, OZil® torsional, U/S, or AquaLase® handpieces in the absence of irrigation flow and/or in the presence of reduced or lost aspiration flow can cause excessive heating and potential thermal injury to adjacent eye tissues.
ATTENTION: Reference the Directions for Use labeling for a complete listing of indications, warnings and precautions.
Maria H. Berrocal, MD, has consulted for Alcon and Alimera.
Timothy G. Murray, MD, is a consultant for Alcon and ThromboGenics, Inc.
Carl D. Regillo, MD, has received research support from, and provided consulting for, Alcon and Bausch + Lomb. He has consulted for Abbott Medical Optics (AMO).
Wayne A. Solley, MD, has received honoraria and educational grants from Alcon.
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