No Zonules? No problem
In this third part of the ‘Complex Cases, Simplified’ series, Dr Brandon Ayres, MD, shares his experience using the MST Capsule Retractors, Chang Modification to manage complicated cataract cases with zonulopathy.
Traumatic Zonulopathy & Global Zonulopathy
Brandon Ayres, MD. Willis Eye Hospital (Philadelphia, PA, USA); American Board of Ophthalmology; Instructor, Sidney Kimmel College of Medicine at Thomas Jefferson University (Philadelphia, PA, USA)
Deficiency of zonular support increases the risk of complications in cataract surgery, including posterior capsular rupture, vitreous loss, and lens dislocation and decentration. A quality capsular support system is therefore an essential management tool for patients with zonulopathy.[1]
Zonulopahty cases can be some of the most challenging that we deal with and one of my favorite devices to tackle these cases is the MST Capsule Retractors (MCR), Chang Modification. In this complex case described below, I used the MCR, Chang modification. This new generation capsule retractors benefit from a closed loop which minimize the risk of the capsular tension ring becoming entangled with the capsular support hook. It’s a little bit smaller than the classic version, with an improved angulation to keep the IOL in the equator of the bag further from the cornea, adding regional stability in patients with zonulopathy.
Tip — Given that it’s a disposable device, an ‘off label’ use is the ability to cut the ends on the retractors, preventing those little “spider” legs sticking out of the limbus from getting trapped on the surgical draping or lid margin.
Traumatic Zonulopathy — In this case, the patient, a police officer, presented with both a coloboma and a traumatic cataract in one eye. A large area of traumatic zonulopathy and zonular loss was evident.
I used two to three Chang modified capsule retractors to restabilize the lens, allowing me to move forward with the case without difficulty.
I used a capsule tension ring and it’s much easier and I feel much more comfortable putting in a capsule tension ring with the new Chang modification retractor. Why? because I can see the end of the capsule tension ring wrap around and I don’t have to worry about capturing the open loop design of the original capsule retractors.
The lens went in but was still shifting so I added a capsule stabilizing segment in this case.
Global Zonulopathy — In a recent case, a patient presented with a subluxated crystalline and high myopia, leaving basically no zonules. The patient had implantable collamer lens (ICL) placed some time ago, but these had to be removed due to dislocation.
As a result of the global zonulopathy, it can be challenging to puncture the capsule. By using a sharp blade, I was able to get a puncture wound in the capsule. I decided to do a bimanual capsulorhexis, holding a fragment of the capsule with the 25g Snyder Grasper (MST) and proceeding with the capsulorhexis using the 23g Güell Capsulorhexis Forceps (MST). The Güell forceps provide great visibility and control at the tip.
Then, I placed only three of the hooks, which were enough to hold the lens in place.
Even with global zonulopathy 3 to 4 MCRs will prevent posterior dislocation without trauma to the anterior capsule. The MCRs maintain stability, allowing lens removal via anterior approach.
My goal in this case was not to save the capsular bag, but to prevent the lens from falling into the vitreous cavity and so becoming a retinal issue. As the patient had a soft lens, I used a vitrector to be ready to remove any potential vitreous humor as well as for irrigation and aspiration of the lens, instead of the traditional phacoemulsification approach.
I concluded the surgery with an intrascleral haptic fixation which facilitates the placement of the IOL in eyes with lack of capsular and zonular support.
In cases like this one with zonules that are weakened, surgery can still proceed smoothly, with ease and safely, largely due to the capsule retractor’s ability to stabilize even the loosest lens, so, no zonules equals no problem!
They are also easily removed. I like to take them out through the main incision, but you can remove them through the primary paracenteses. Personally, I think if you have a main incision there, why not go ahead and use it.
Hint — You can rest assured with the new MCR, Chang modification that your case will be made much easier. What could be a very complex procedure can be transformed into a routine surgery.
Conclusion
The MST Capsule Retractors, Chang modification allow zonulopathy cases to be performed in a more standardized way, supporting the surgeon by their purposeful design, exact angulation, ability to support and stabilize the capsular bag.
Key Learnings
Creating a capsulotomy in cases with global zonulopathy can be challenging — bimanual approach using atraumatic forceps to hold the capsule and dedicated capsulorhexis forces to create the opening facilitates capsulotomy in subluxated lenses.
When using the MCR, Chang modification, introduce the capsule retractors slowly and precisely.
Maintaining capsular support throughout the surgery is a key step and a crucial element within the procedure.
Remove through the main incision to avoid or minimize surgical trauma.
References
1. Reidel PJ, Samuelson TW. Capsular tension rings. Colvard DM, editor. Los Angeles, CA 2009. 115–21 p. From an article by Eric Shieh, Kevin M. Miller, MD https://eyewiki.aao.org/Capsular_Support_Devices#cite_note-:0-1 Capsular Support Devices.
2. Yaguchi S, Yaguchi S, Asano Y, Aoki S, Hamakawa M, et al. (2015) Categorization and Surgical Techniques of Weak Zonule Based on Findings at Capsulorhexis during Cataract Surgery. J Clin Exp Ophthalmol 6: 407.
3. Shingleton BJ, Neo YN, Cvintal V, Shaikh AM, Liberman P, et al. (2017) Outcome of phacoemulsification and intraocular lens implantion in eyes with pseudoexfoliation and weak zonules. Acta Ophthalmol 95: 182–187.
