5 Malyugin Ring Despite the different treatments available to expand the iris during cataract extraction, performing surgery on an eye with a small pupil remains technically challenging. Complications that can occur during small pupil phacoemulsification surgery include iris damage and bleeding, iris prolapse through the paracentesis or the main wound, anterior capsule damage, incomplete evacuation of the cortical material, and difficulties with placing and aligning the intraocular lens (IOL) in the capsular bag. Various pupil expansion devices are currently available, such as iris hooks, rings, and expanders. Among them, the Malyugin ring (MicroSurgical Technologies [MST], Redmond, WA) is currently one of the most popular. It was developed to give surgeons a reliable device that is easy to use, expands the pupil up to 7.0 mm, and protects the iris from damage.1,2 This chapter describes the technique of implantation and removal of the Malyugin ring in patients with small pupils or intraoperative floppy iris syndrome (IFIS) through various size incisions. Tips on how to better manipulate the device in and out of the eye and to avoid complications are provided. Special attention is paid to the use of the Malyugin ring pupil issues in femtosecond laser–assisted cataract surgery (FLACS). The Malyugin ring is made of 4/0 polypropylene, and has a one-piece design with a square shape and four equidistantly located circular loops (Fig. 5.1). The loops located at each corner have a wedge-shaped gap used to accommodate the iris tissue. The thin scroll design has eight points of fixation, providing the surgeon with a round pupil instead of the square one that is formed after using four iris hooks (Fig. 5.2). The Malyugin ring comes in two sizes: 6.25 mm and 7.0 mm. The advantage of the smaller ring is that it is easier to insert and to remove. It is better for eyes with a small white-to-white diameter. The advantage of the 7.0-mm ring is that one can use it if the pupil is larger at the start of the procedure, as occurs often in IFIS cases. The Malyugin Ring System produced by MST consists of a presterilized single-use holder containing the ring and injector. The hook of the injection device is used to catch the proximal loops of the Malyugin ring and retract it inside the tube as well as expel it from the injector. A stepwise approach to manage small pupils is preferable. It is recommended to start with an intracameral injection of phenylephrine or epinephrine and eventually work up to mechanical pupil expansion. Surgical steps of the Malyugin ring implantation are as follows. After topical anesthesia is applied, a clear corneal incision is performed and anesthetic solution and ophthalmic viscosurgical device (OVD) are both injected into the anterior chamber in a sequential manner. It may be helpful to inject a small amount of OVD under the iris, at the pupillary margin, to slightly elevate the pupillary margin. This will facilitate the positioning of the ring loops. The Malyugin ring is loaded into the injector. The injector tip is inserted through a 2.2-mm or wider clear corneal incision. The tip of the injector is passed through the anterior chamber toward the pupillary margin (Fig. 5.3). While slowly pushing on the injector plunger, the ring is released from the tip ∼ 1.0 to 2.0 mm forward, and the distal scroll is engaged in the distal iris. Continued pressure on the injector plunger, while simultaneously slowly withdrawing the injector, permits injection of the remainder of the ring. The lateral scrolls emerge from the injector tube and one (or both) of them simultaneously catches the iris margins. If the lateral scrolls do not engage the pupillary margin, they are positioned with the Osher/Malyugin ring manipulator as noted below. When the proximal scroll is expelled from the injector, the injector hook is moved forward to the point when it is no longer holding the ring (Fig. 5.4). At this moment the scroll is usually lying on top of the injector platform. The injector is withdrawn from the eye, and the Osher/Malyugin ring manipulator is used to engage the proximal ring scroll (Fig. 5.5). In some cases the ring manipulator is inserted through the paracentesis, which helps to disengage the proximal scroll from the injector hook by displacing the scroll to the side and away from injector tip. The next steps of the surgical procedure are straightforward and are mostly specific to the lens capsule properties and nucleus hardness. These steps include anterior curvilinear capsulorrhexis, hydrodissection and hydrodelineation, ultrasonic nucleus fragmentation, evacuation of the cortical material, and IOL implantation (Figs. 5.6, 5.7, 5.8). The Malyugin ring is removed from the eye in reverse order of its implantation. The anterior chamber should be re-formed with cohesive OVD. The Malyugin ring manipulator inserted through the main incision catches the distal scroll and moves it toward the center of the pupil and up until it disengages. Then this scroll is moved back toward the iris periphery to displace the ring downward. This maneuver helps to expose the proximal scroll, which is then disengaged by the manipulator from the iris and placed onto the anterior iris surface. Then the injector’s platform is positioned under the proximal scroll, with the hook fully deployed from the tube. The proximal scroll catches with the hook and the plunger is moved backward (Fig. 5.9). The ring is retracted inside the injector tube. Being retracted halfway inside the injector, one of the side scrolls sits on top of the injector tube and does not allow the ring to go inside the injector completely. To fully retract the ring, I recommend pressing with the side-port instrument on both lateral scrolls simultaneously when they merge together near the tip of the injector. With this maneuver the surgeon guides the scrolls inside the injector. With a 2.75-mm main incision, it is possible to stop retracting the ring when one of the lateral scrolls rides above the cannula and then remove the whole assembly.
Malyugin Ring Design and Characteristics
Surgical Technique with the Malyugin Ring
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