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An efficient vitrectomy may make the difference when faced with a broken capsule
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NEW YORK — If a surgeon employs proper surgical technique, uses modern instrumentation and adheres to four simple principles, the majority of broken capsule cases, even those requiring a vitrectomy, will enjoy an excellent visual and anatomic outcome.
During the Eighth Annual Ocular Surgery News Symposium on Cataract, Glaucoma and Refractive Surgery, Louis D. “Skip” Nichamin, MD, explained his procedure for an efficient vitrectomy for a cataract surgeon.
Dr. Nichamin said he regularly performs both anterior and posterior segment surgeries. “Over the years, it’s afforded me some very deep-seated feelings and convictions as to how we, as anterior segment surgeons, should manage an open capsule and vitreous loss.”
The process for a good vitrectomy
What happens when a surgeon recognizes a problem and is in the midst of phaco? According to Dr. Nichamin, first, surgeons must develop the discipline to stop working the instant they suspect that there is a problem.
A classic sign of danger is deepening of the anterior chamber. But Dr. Nichamin said he looks for a more subtle and important sign — the deepening of the posterior chamber. A surgeon must look for a slight increase in space between the posterior aspect of the iris and the anterior lens capsule, looking for lens tilt.
A sudden decrease in the ability to rotate the lens may mean a change in the integrity of the zonules and one must be on the lookout for any change in fluidics. Such a change may be a loss of followability or cutting action, it may be a technical or equipment problem, but it also may be a breach in the integrity of a capsule.
The goal in this situation is to remove the remaining lens material. With the proper technique, a surgeon can access 360° of the capsular fornix and clean up the anterior segment to the point where it should be indistinguishable from an uncomplicated case. If vitreous presents, it is mandated that a proper vitrectomy be done.
Be careful
Secondly, one must not simply withdraw the instrument from the eye. The surgeon must stabilize the anterior chamber with viscoelastic and at the same time support the remaining lens material with the viscoelastic. At this point, one can carefully exit the eye, avoiding sudden decompression, and then take a moment to assess the anatomy. If appropriate, based on surgeon experience and on the clinical situation, he or she can continue phacoemulsification by plugging the capsular rent with a retentive and dispersive viscoelastic, Dr. Nichamin said.
Surgeons have two enemies when faced with an open capsule, the first of which is hypotony. Therefore, the appropriate thing to do is to fill the anterior chamber with viscoelastic immediately. “I rather rudely grab the viscoelastic, come in through the side port and stabilize the anterior chamber and then gradually withdraw either the phaco instrument or the irrigation and aspiration [I&A] instrument from the main wound,” Dr. Nichamin said.
Don’t make matters worse
The third point is to avoid enlarging the posterior capsular tear once it is detected. “How do we avoid enlarging the capsular tear? Well, I said our first enemy is hypotony. Our second enemy is unnecessary infusion. It is typically high volumes and high flow rates of infusion that, literally, blow open the capsule and force the vitreous forward,” Dr. Nichamin said.
A surgeon only wants to use that amount of infusion that will equal the amount of material that he or she is removing. And in this situation, a surgeon is going to be removing very small amounts of material. So only use the most minimal infusion and, in some cases, a surgeon can actually eliminate infusion and work in a dry state maintained with viscoelastic, he added.
The key to using low levels of infusion is to maintain a closed chamber, and to do so there must be watertight incisions. And as soon as it is possible, convert an irregular tear into a continuous posterior capsulorrhexis.
If the situation dictates conversion, then it is important to be generous and enlarge the wound. If necessary, abandon a clear corneal incision and create a new scleral tunnel incision several clock hours away. Then, gently extrude the lens material. Dr. Nichamin said he prefers to try to glide the material out either with a modified lens loop, viscoelastic or lens hooks.
Dr. Nichamin said he routinely avoids any type of automated I&A and turns to a manual form of cortex removal, or at least cortex mobilization wherein he uses cannulas. “I simply bend a 27-gauge cannula, attach it to a TB syringe filled with balanced salt solution and then gently tease the cortical material out of the capsular fornix. If we make two, three or four additional side port incisions or paracenteses, we can then access 360° of the capsular fornix, and gently tease this material up and into the anterior chamber.”
The surgeon does not necessarily have to remove the material at this point, he said. “Just bring it up into the anterior chamber, place the implant, bring the pupil down, and then one may enter with some degree of impunity, using infusion, and remove the remaining viscoelastic and lens material. If vitreous is already mixed into the situation here, then the surgeon should use a vitrectomy instrument to remove the remaining lens material,” Dr. Nichamin said.
Save the capsule
In regards to vitrectomy, the same principles hold true. It is important to try to save as much capsule as possible, using only a minimal amount of infusion. The goal is to remove only that vitreous that presents anterior to the plane of the capsule. This must be done without conveying unnecessary vitreoretinal traction forces.
Surgeons should separate infusion from the vitrectomy tip. Infusion should not be placed in the same location where one is trying to gently aspirate and cut vitreous. The technique of a bimanual vitrectomy, as expounded upon by many others, is absolutely essential.
Finally, surgeons should be using the lowest possible vacuum settings. According to Dr. Nichamin, 50 mm Hg to 100 mm Hg will suffice at the highest possible cutting rates. Some of the new instrumentation will cut at rates of 1,500 cuts/minute.
Preparing for a vitrectomy
Dr. Nichamin explained how his operating room is prepared to deal with the capsular rupture. He has on standby a vitrectomy “kit” containing a 20-gauge vitrector and a separate dedicated infusion cannula (Storz E-4421-S21). Though not a regular user of chondroitin sulfate, Dr. Nichamin wants it around when faced with an open capsule, so a vial of Viscoat (chondroitin sulfate, sodium hyalur-onate, Alcon) also is contained within the kit. Visitec (Grevesmühlen, Germany) and other companies make downsized lens glides that will fit through a 3-mm incision. He usually has a microvitreoretinal (MVR) blade handy to create the exact sized incisions for a 20- gauge instrument. And, of course, sutures are available.
For Your Information:
- Louis D. “Skip” Nichamin, MD,can be reached at the Laurel Eye Clinic, 50 Waterford Pike, Brookville, PA 15825; (814) 849-8344; fax: (814) 849-7130; e-mail: nichamin@laureleye.com. Dr. Nichamin has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.