Positioning tools for ring device facilitate pupil engagement

Two new instruments engage the scrolls of the Malyugin ring to assist with positioning.

Introduction

Thomas John

Small pupil cataract surgery can be challenging and may be associated with a higher risk of potential intraoperative complications, including vitreous loss, iris damage and retained lens material.

Ophthalmic surgeons have used various techniques to deal with small pupil phacoemulsification, including the use of pharmacologic agents and mechanical pupil dilation using bimanual stretching, nylon iris hooks, extendable titanium fingers (Beehler pupil dilator, Ambler Surgical), and rings made of silicone (Graether 2000 pupil expander, Eagle Vision), flexible polyurethane (Perfect Pupil, Ambler Surgical) and elastic PMMA (Morcher pupil dilator, FCI Ophthalmics).

The recent addition to this list of instruments is the Malyugin ring, which is gaining in popularity among ophthalmic surgeons. However, there appear to be difficulties in intraocular manipulation and proper intraocular placement of this ring to engage the pupillary margin. In this column, Dr. Howard Krausz describes two new instruments to facilitate the use of the Malyugin ring in both the pupillary engagement and disengagement during small pupil cataract surgery.

– Thomas John, MD
OSN Surgical Maneuvers Editor

Howard I. Krausz

Many eye surgeons now prefer the Malyugin ring rather than iris hooks for dilating small pupils.

The new 7-mm Malyugin ring (MicroSurgical Technology) is particularly useful for maintaining mydriasis in intraoperative floppy iris syndrome cases due to Flomax (tamsulosin, Boehringer Ingelheim).

Iris hooks have the disadvantages of requiring multiple incisions, pulling the iris anteriorly, notching the pupil sphincter and sometimes being displaced by contact with eyelids. They can be particularly difficult to place in myopic eyes with very deep anterior chambers.

Technique for Malyugin ring

The Malyugin ring nicely dilates the pupil without displacing the iris plane or requiring additional incisions. Injection into the anterior chamber through the temporal cataract surgical wound is easily accomplished with the accompanying injector supplied by MicroSurgical Technology. Usually the leading scroll of the ring will capture the opposite nasal pupil margin during injection, but further manipulations of the ring may be required to place one or both of the lateral (superior and inferior) scrolls and are always needed for the proximal (temporal) scroll.

Typically, a Sinskey or Lester hook is used to manipulate the scrolls of the Malyugin ring to capture the pupil between the two coils of each scroll. This can be difficult to accomplish for several reasons. The instrument must cross over the ring to gain access to the inside of each scroll. The Sinskey hook in particular can easily slip through the scroll and continue posteriorly. Hooks have no means of grasping the scrolls. Placement of the proximal scroll is especially difficult due to its subincisional location, requiring a hook to dive down posteriorly and then somehow move the scroll centrally. An option is to dial the ring around to move the proximal scroll away from the incision before trying to hook and place it in the pupil. Because hooks cannot grasp and direct the rings, there is a risk of losing a scroll behind the pupil, where its retrieval can be time-consuming and potentially dangerous.

Tools for Malyugin ring

I designed new Malyugin ring tools to engage the upper coil of each scroll from the outside so that the scroll can be moved centrally and also positioned up or down as needed to capture the pupil. In the process, the scroll is also spread apart slightly, which also facilitates pupil engagement or release.

Figure 1. Placing a lateral scroll in the pupil. Images: Krausz HI

One instrument (Figure 1) is double-ended, with “spoons” for engaging either the scroll to the right or the scroll to the left of the cataract incision (lateral scrolls). The spoon ends are angled up from the instrument shaft so they act parallel to the iris and ring. The instrument also fits through an enlarged side-port incision to allow manipulation of the distal scroll or even the proximal scroll.

A second instrument (Figures 2 and 3) was designed just for accessing and engaging the outside of the proximal (subincisional) scroll. Its engagement surface is also angled up from the instrument shaft. This “Malyugin ring pusher” is likely the more indispensable of the two instruments.

Figure 2. Placing the proximal scroll.

Figure 3. Releasing the proximal scroll for ring removal.

There are several advantages of these Malyugin ring manipulators:

• The Malyugin ring scrolls can be engaged, cupping the coil with a miniature spoon.
• Manipulation of the ring scrolls is enabled in three dimensions, anterior and posterior as well as in the iris plane.
• The scroll coils can be spread apart slightly to facilitate pupil engagement and release.
• Double-ended instruments work for both opposing pairs of scrolls.
• The ring pusher tool easily engages and releases the more challenging proximal scroll.
• Patient safety is increased because the Malyugin ring can be positioned more reliably than with other instruments.

The new Krausz Malyugin ring manipulators are available from Rhein Medical.

• Howard I. Krausz, PhD, MD, can be reached at Hidden Valley Eye Associates, 800 E. Ohio Ave., Escondido, CA 92025; 760-746-3937; fax: 760-746-3991; e-mail: krausz@roadrunner.com.
• See video of this technique at http://www.youtube.com/watch?v=wUZ4hMXCu6c.