miLOOP simplifies cataract surgery training for high-risk cases
The device helps build new surgeons' confidence through repetition and consistent outcomes.
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Training ophthalmology residents on complicated cataract cases can be, well, complicated. They need to be able to practice surgical maneuvers in a low-stress environment, allowing time for repetition and mastery of technique, so that their execution in the OR will be flawless. Encountering a complication that leads to an adverse outcome can be a devastating experience for a surgeon in the making, and the resulting hit to his or her confidence is a significant setback. Often these residents will become more timid and indecisive, which leads to an increased likelihood of more trouble.
Two years ago, at the Grady Eye Clinic as part of the Emory University Medical School’s resident training program, we incorporated the miLOOP device (Zeiss) as an additional tool for safer and less traumatic nuclear disassembly in very dense, hard black cataracts. The nature of these lenses poses an increased risk for complications such as posterior capsular rupture and zonular dialysis, raising the surgical stakes and increasing trainees’ anxiety during nuclear disassembly. Using the miLOOP to accomplish this step is a game-changer for our residents and, most importantly, our patients.
Snare-like filament takes advantage of geometry
The relatively inexpensive and disposable miLOOP is an endocapsular ring made of a strong nitinol filament. Injected through a small clear corneal incision, the loop ensnares the nucleus by extending under the anterior capsule and circling around the nucleus to the equator and then the posterior surface. As the loop is withdrawn, it bisects the cataract, making a full-thickness cut. The surgeon can use the device to rotate the nucleus and further break it into quarters or even smaller pieces if desired.
The miLOOP is designed to minimize capsular stress, including in dense nuclei, by using centripetal force, ie, “out-in” nucleus disassembly. In this manner, the super-elastic thin filament works to cut through the lens independent of phacoemulsification energy. Being able to reduce any unnecessary or additional trauma to the corneal endothelium is paramount for safety and protecting the integrity of the capsule.
How we teach it
Source: Gene Kim, MD
When residents begin practicing with any new techniques or devices in cataract surgery, there are certain elements to keep in mind. Easy access to wet labs is crucial, and I believe in removing all obstacles to their use. Surgeons in training should have good models to work with, instruments in proper working order, an emphasis on ergonomics and demonstrations of proper technique. Residents need supervision, and objective feedback is invaluable as they learn to master the steps of cataract surgery.
Here are some important instructional pearls for the miLOOP:
- Do not stress the zonules. We teach residents to take care not to stress the zonules when deploying the device and retracting the snare; unwarranted moves will apply translational forces through the loop. They should understand the geometry of the tool and how it fits the ocular anatomy, aiming slightly short of center when deploying so as not to affect the subincisional zonules. As the miLOOP fills the entire capsular bag, the surgeon must avoid pushing and pulling on the device or moving it right or left.
- Deploy under the capsule. We tell residents to ensure they deploy the miLOOP underneath the anterior capsule. It is possible to mistakenly go over the capsule and tear zonules as the tool rotates.
- Stabilize. When retracting the snare, it will be necessary for surgeons to practice stabilizing the lens with an instrument in their nondominant hand. This is helpful to ensure that the lens does not tilt up, especially in a very dense lens.
- Be flexible. To optimize the miLOOP’s entry into and exit from the eye, surgeons should have flexibility in terms of where their hands are positioned. The snare must be retracted tight, making the device as small as possible so as not to damage the cornea. To master this technique, residents need to learn to pivot almost 90° to safely remove the loop, especially with a smaller incision size.
There are no shortcuts
As with all surgical skills, there is a learning curve — and no substitute for a lot of practice. Our residents gain experience using the miLOOP in the wet lab, performing the techniques over and over again. They get used to the geometry of the device, develop a feel for the snare, and learn how it is best deployed, retracted and rotated.
We routinely see dense cataracts in our patient population at Grady, and the miLOOP has changed how we approach surgery. The tool has now made these potentially challenging cases into more routine surgeries that proceed seamlessly. Residents are intimidated by dense lenses, and certainly any complications they encounter can be shattering to their confidence, not to mention the adverse impact on patient outcomes. Yet, it is precisely these patients with severely compromised vision due to their dense cataracts who are the most appreciative of their postoperative results.
- For more information:
- Yousuf M. Khalifa, MD, chief of ophthalmology at Grady Eye Clinic and associate professor of ophthalmology, Section of Cornea, External Disease and Refractive Surgery, Emory University School of Medicine, can be reached at email: yousuf.khalifa@emoryhealthcare.org.
Disclosure: Khalifa reports he is a consultant for Carl Zeiss Meditec.