Many anterior segment surgeons, trained primarily to perform phacoemulsification, have relatively little experience with manual small incision cataract surgery ( MSICS). The ability to perform MSICS, however, should be in every cataract surgeon’s skill set. In select cases with extremely dense nuclei and/or endothelial dystrophy, a well-performed MSICS procedure can provide a superior surgical option to phacoemulsification. This video describes a step-by-step approach to manual small incision cataract surgery that can be easily learned and successfully performed by any experienced phaco surgeon.
Lecturer: D. Michael Colvard MD FACS, Clinical Professor of Ophthalmology, volunteer faculty, UCLA Geffen School of Medicine, Los Angeles, CA
The cornerstone of manual small incision, extra capsular surgery is, incision construction. The idea was to create a six to eight millimeter scleral incision that is frown shaped, and 1.5 to two millimeters from the Limbus. A scleral tunnel incision is then carried, 1.5 to two millimeters into clear cornea. The goal is to try to create an incision that is watertight. But it’s important to say from the outset, that this isn’t always possible. Often when the surgeon is dealing with a very large, dense cataract with a nucleus is enormous and there’s virtually no cortex is necessary to enlarge the incision. This increases the likelihood that you may have to suture this incision. But having said this, it’s very easy for an experienced physical surgeon to perform sutureless extra capsular surgery. In most cases, it’s all about good incision construction. The internal corneal incision is best made with a bevel up Crescent blade with a goal of creating a funnel shaped incision. The cord length of the internal incision should be approximately 12 millimeters. The trick to creating this large internal incision is burrowing laterally into the Peripheral Cornea and slightly under the Limbus on both sides of the internal incision. The next step is to enter the anterior chamber using a keratome. Many surgeons prefer to make a three millimeter internal incision first, this allows the surgeon to have better anterior chamber maintenance during the creation of the anterior capsulotomy. But whether you start with a three millimeter entry or open the internal incision completely before creating the anterior capsulotomy, take care not to lose the internal corneal shelf that you’ve made by entering the anterior chamber prematurely. There are many different types of anterior capsulotomies used by MSICS surgeons. But most surgeons trained to perform phacoemulsification, prefer either capsulorrhexis or a can opener capsulotomy. Trypan blue is always helpful in these eyes with very dense cataracts especially if one is performing capsulorrhexis. Capsulorrhexis in MSICS procedures has all the advantages that are well known to phaco surgeons. But one disadvantage is that with these very large dense cataracts with virtually no cortex, it’s difficult to prolapse the huge nucleus through the smaller capsulorhexis opening. In these cases, a can opener capsulotomy comes in handy because it can make nucleus delivery much less difficult. After the anterior capsulotomy has been performed, the internal incision may then be opened fully with a keratome. To maintain the full extent of the internal corneal shelf, it is helpful to open the internal incision with forward strokes of the blade. If the incision is cut with downward strokes or in a saw like fashion, it’s much easier to lose the full extent of the corneal shelf that you’ve created. The greatest challenge facing a surgeon who is inexperienced in performing manual extracapsular cataract surgery, is the delivery of the nucleus out of the capsular bag. There are dozens of ways to do this but one way that is safe and reliable and easily performed by a surgeon who is experienced in phacoemulsification, is a method that I call the slip and slide technique. The first step is to hydro dissect the nucleus, then place some OVD in the anterior chamber, not too much and then introduce a bent needle or sinskey hook into the anterior chamber through a side port. Gently push the tip of the needle or the hook into the anterior surface to the nucleus slightly distal to the center of the nucleus and gently push the nucleus away from the primary incision while pressing slightly downward. This will cause the proximal edge in the nucleus to rise up slightly.
At the same time, gently depress the edge of the incision and the edge of the capsulotomy, with the edge of the OVD cannula. This will shallow the anterior chamber slightly, and the nucleus will rise up even higher. Then slip the edge of the cannula under the nucleus and inject a little OVD. Once you’ve created a space between the nucleus and the posterior capsule, slide the OVD cannula under the nucleus, inject more OVD and lift the nucleus out of the capsular bag. The nucleus can then be safely removed either by using an irrigating vectors or Lens Loop. A key point is to remember to press down gently on the incision as you extract the nucleus. This allows the nucleus to be removed from the anterior chamber without rubbing against the corneal endothelium. You will be inclined to lift up When extracting the nucleus at first, try not to do it. Also, if the nucleus can’t be extracted with relative ease through the incision that you have made, enlarge the incision. It’s better to have to suture the incision than to try to muscle the nucleus out of the eye through an incision that’s too small. After removal of the nucleus, there is always some residual lens material in the anterior chamber or stuck in the incision. This material can be irrigated out of the eye with a Simcoe cannula through the primary incision. Cortex removal can be accomplished by introducing the Simcoe cannula through the side port. This provides good chamber maintenance, with excellent visualization to an irrigation aspiration and easy access to sub-incisional cortex. After IOL placement, the Simcoe device can be used to remove OVD from the anterior chamber and from behind the IOL. The incisions are then hydrated, checked with gentle pressure and a fluorescent strip to ensure watertight closure. If there is evidence of a leak, a single running 10-0 nylon X suture with a knot buried within the incision will generally provide a watertight closure. The suture material is then covered with conjunctiva. A running nylon suture without external knots that is completely covered by conjunctiva, generally will not erode, will not need to be removed and tends to remain comfortable for patients indefinitely.
April 14, 2022
2 thoughts on “Surgery: MSICS for the Phaco Surgeon”
very great thank you