Part 2

The Malyugin Ring 2.0 plays an expanding role in small pupil surgery

In this second article of the ‘Complex Cases, Simplified’ series, Dr. Boris Malyugin, M.D., the inventor of the Malyugin Ring (Figure 1), describes the device in complex small pupil cases and provides an overview of his surgical steps in cases requiring the use of the ring.

Figure 1: The Malyugin Ring 2.0 by MST (MicroSurgical Technology Inc.)

Prof. Boris Malyugin, M.D. , Professor of Ophthalmology, Deputy Director General (R&D, Edu) at the S. Fyodorov Eye Microsurgery State Institution, Moscow, Russia

Malyugin Ring 2.0 — Small pupil is a well-known risk factor associated with many complications in cataract surgery.1 To address this risk-factor, I developed (with MST) the new generation Malyugin Ring 2.0 which is available in 6.25 mm and 7.0 mm. The new version is made of smaller-gauge material than the Malyugin Ring Classic (5–0 polypropylene versus 4–0 polypropylene). This makes it thinner, more flexible and friendlier to the iris tissue. The injector has also been redesigned and is much slimmer, making it easier to pass through an incision of only 2.0 mm (Figure 2).

Figure 2. Scroll gap comparison between Malyugin Ring Classic and 2.0

Key considerations for the use of the Malyugin Ring 2.0 — The new generation Malyugin Ring 2.0 is in my opinion ideal in situations such as Intraoperative Floppy Iris Syndrome (IFIS). With IFIS patients there is no need to open the very small pupil because it is mostly mid-dilated or well dilated at the start of the case. It is during the surgery that the pupil begins to constrict, and the iris starts billowing.

Hint -The pupil is quite elastic in IFIS cases and so I use size 7.0 mm Malyugin Ring 2.0 here.

For Malyugin Ring 2.0 I do not like the pupil to be very small pre-implantation. If it is very small (~3.0mm) and the iris tissue is fibrotic, the Malyugin Ring can become distorted while engaging the lateral and/or proximal scrolls. Thus, the pupil size should ideally be slightly more than 4 mm. The Malyugin Ring 2.0 is a useful tool in more difficult surgeries as well.

Femtosecond laser-assisted cataract surgery (FLACS) is another situation where I use the Malyugin Ring 2.0 to dilate the pupil before applying the laser energy. I initially use only 2.0mm clear corneal incision and no additional paracenteses to implant the ring with the help of the Osher ring manipulator (MST). I leave dispersive ophthalmic viscoelastic device (OVD) in the anterior chamber, making sure there are no air bubbles entrapped. And in spite of the fact that the incision is very small, only 2.0mm — I nevertheless like to place a single 10–0 nylon suture to temporarily seal the wound in order to counter the presure from the laser interface.

The Malyugin Ring 2.0 in complex cases — Complexities, such as small pupil and weak zonules, challenge any surgeon. Not only do you need to open the pupil, but also you need to overcome the difficulties the weak zonules present.

In these complicated cases I implement the following surgical steps:

· To start, I implant the Malyugin Ring 2.0. At the very beginning I like to inject some viscoelastic behind the iris to lift it a little above the plane of the capsule which helps to engage the corner scrolls of the device more easily.

· Once the ring is in place, I perform the capsulotomy (Figure 3). At this stage it is easier to understand how much zonular laxity is present — for example, if there are capsular folds or the lens becomes mobile when you tear the anterior flap, that gives you an idea that the zonular laxity is quite significant.

Figure 3: Capsulorhexis- Video image — Dr Boris Malyugin using the new generation Malyugin Ring 2.0 intraoperatively during capsulorhexis procedure.

· Following the capsulorhexis, I begin hydrodissection, which is performed between the capsule and the cataract cortex to free the adhesions in between cataract and the capsular bag. Allowing the lens to rotate freely is very important, especially in weak zonules.

Hint — This needs to be a complete procedure leaving no adhesions behind. If its not complete, and you come to rotate the lens during phacoemulsification, it might cause stress to the zonules and you will cause damage to the zonules and also struggle with the evacuation of the cortical material.

· The next step is nucleus removal with a phaco-chop technique utilizing high vacuum settings, pulsed ultrasound and dual linear footpedal control.

· The residual cortical material is then evacuated from the capsule bag by bimanual irrigation and aspiration (I/A).

· In small pupil cases, I like to use bimanual I/A technique as it allows for more flexibility with access to the cortical material.

· The capsular tension ring (CTR) is best implanted as soon as the capsular bag is free from the cortical material.

· The IOL implantation comes next.

Removal of the Malyugin Ring 2.0 — The ring is removed by releasing the scrolls of the device and retracting it towards the centre. First, I disengage the distal scroll followed by the proximal scroll. I lift it above the iris plane. Then, the proximal scroll is positioned on the inserter footplate and caught by its hook.

The ring is then retracted and both the lateral scrolls glide into the injector tube (Figure 4 & Figure 5) with the assistance of the second instrument. Viscoelastic is removed and the pupil constricts spontaneously.

Figure 4: Removal of the ring with the assistance of the second instrument.

Figure 5: Removal of the Malyugin Ring 2.0 with the assistance of the manipulator. Here the lateral scrolls

In conclusion, the Malyugin Ring 2.0 helps to simplify cases complicated by small pupil and/or weak zonules. The new generation Malyugin Ring is thinner and more flexible, making the implantation and removal easier and gentler to the iris. It is important to know that the gap in between the uper and lower portions of the scrolls in Malyugin Ring 2.0 is wider, making it easier to engage with the pupillary margin.

Key learnings:

· It is important to be aware that small pupils are not only to be considered as a geometrical issue but also as an indicator of coexisting pathology within the eye, such as blood-aqueous barrier disruption, weak zonules, intraocular pressure spikes, etc. Obviously, these eyes are much more difficult to operate on.

· It is essential to fully understand the steps for using the Malyugin Ring 2.0; knowing to be gentle with the iris as each manipulation of the iris may potentially have consequences with post-operative reactions.

· Prior to implanting the Malyugin Ring 2.0, ensure the pupil is not very small to begin with. Its best if its wider than 4.0 mm. Ideally, try to have it mid-size. This is because with mid-sized pupils there is less manipulation and easier implantation of the ring. Sometimes in cases with fibrotic iris, pupil stretching technique helps to prepare the eye for ring implantation.

· Before injecting the ring, inject viscoelastic behind the iris to lift it a little the above the plane of the anterior lens capsule.

· Allow extra time in surgery with complicated cases. Additional surgical manipulations can be longer than anticipated so more time is advisable.

· Consider more aggressive postoperative anti-inflammatory therapy to compensate for the iris surgical trauma and coexisting pathology of the eye making it more prone to inflammation.

References

1. Malyugin, B. Cataract surgery in small pupils. Indian J Ophthalmol. 2017 Dec; 65(12): 1323–1328. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742960/