I have been using the Stellaris (Bausch + Lomb, Aliso Viejo, CA) for coaxial microincision cataract surgery (С-MICS) since its launch in 2007 as my primary phacoemulsification system. The move to C-MICS with the Stellaris PC was natural, in my opinion. Decreasing incision size has been the trend in the history of cataract surgery, and with Stellaris PC, I routinely use a 1.8-mm incision. There was very little that I needed to change in my technique of handling a cataract when transitioning to C-MICS because the Stellaris PC has many useful features.
Safety, Efficiency, and Ease of Use
The basic function of a phaco system is to break up a
cataractous lens, commonly using ultrasound energy, and remove the fragments
from the eye without decreasing the overall volume of the anterior chamber or
damaging any intraocular tissue other than the lens. Working with surgeons, the anterior functionality
of the Stellaris PC system was designed with three goals in mind: safety,
efficiency, and ease of use.
Safety. Safety includes the fluidics components of the Stellaris PC system. StableChamber Fluidics were developed to minimize surge and stabilize the anterior chamber. The fluidics systems were also made robust enough to balance fluid inflow and outflow—even through the smaller phaco tips required for MICS procedures. There is no surge after occlusion break using a 1.8-mm MICS needle and high vacuum settings
Figure 1. There is no surge after occlusion break using an 1.8-mm MICS needle and high vacuum settings.
Efficiency. Efficiency includes the elements of controlling cutting dynamics and power modulation including increasing stroke length of the phaco needle to improve mechanical cutting efficiency. The Attune energy management system allows the surgeon to customize all aspects of the ultrasound pulse to their technique and allows customized pulse duration and interval, while the Advanced Waveform Modulation allows variable wavefront duration and depth
Figure 2. The Attune energy management system allows the surgeon to customize all aspects of the ultrasound pulse to their technique and allows customized pulse duration and interval, while the Advanced Waveform Modulation allows variable wavefront duration and depth.
The use of a 28-kHz frequency handpiece maximizes cavitation for enhanced nuclear emulsification and also eliminates the chance of thermal wound damage.
Ease of use. Ease of use includes improved interface and design features that ensure the system is simple and convenient to use for surgeons and OR staff alike. For example, the wireless footpedal is designed with an easy left/right offset for dual-linear mode. The footpedal controls power and vacuum, has an easy tension adjustment, is programmable, and is ergonomically designed. I use dual-linear for all my cases, which is helpful because I do not need to use multiple settings for the different steps in my surgery. For example, with other machines, a surgeon would need one setting for epinucleus, another for sculpting, and yet another for quadrant removal. With the Stellaris PC dual-linear footpedal control, I use only one setting.
For a quick chop technique, I most often use a linear ultrasound power of 30%, 80 pulses/s, and 50% duty cycle. My vacuum in ultrasonic phase is 400 mm Hg and the IV pole height is 100 cm. Although I use aggressive vacuum settings, the anterior chamber remains stable and the nucleus is effectively emulsified using vacuum-assisted ultrasonic aspiration of the lens. The stability of the chamber during the procedure can be gauged by pupil size as the fragment of the nucleus passes through the needle.
CLICK TO WATCH DR. MALYUGIN PERFORM QUICK CHOP PHACO
A Complete MICS Procedure
In my opinion, there is no reason to enlarge an incision to implant the IOL in a C-MICS procedure. I have been implanting the Akreos MICS IOL (Bausch + Lomb [available in Europe]), which has an innovative design that incorporates different haptic zones with an absorption zone that can adapt for the different capsular bag sizes and
capsular contraction that occurs in the postoperative period in some of
our patients.
Figure 3. The Akreos MICS IOL incorporates different haptic zones with an absorption zone that can adapt for the different capsular bag sizes and capsular contraction.
CLICK TO SEE ADAPTATION OF THE AKREOS IOL ABSORPTION ZONE
Figure 4. The injector stays outside the anterior chamber and the corneal tunnel is utilized as an extension of the cartridge.
I use a linear injection wound-assisted technique to maintain the 1.8-mm incision and to reduce stress on the cornea during the IOL injection portion of the surgery. In the linear injection wound-assisted technique, we use a corneal tunnel to inject the IOL. The injector stays outside the anterior chamber and the corneal tunnel is utilized as an extension of the cartridge.
Corneal stress is minimized because we are not introducing the cartridge inside the wound—the internal cartridge diameter (1.25 mm) fits to the linear incision size (1.8 mm).
CLICK TO SEE DR. MALYUGIN DEMONSTRATE THE LINEAR INJECTION WOUND-ASSISTED TECHNIQUE.
Performing a C-MICS procedure without enlarging the wound for IOL implantation has been shown to significantly reduce surgically induced astigmatism and increase visual recovery postoperatively when compared with small incision (2.8 mm) cataract surgery. 1
Figure 5. Performing a C-MICS procedure without enlarging the wound for IOL implantation has been shown to significantly reduce surgically induced astigmatism and increase visual recovery postoperatively when compared with small incision (2.8 mm) cataract surgery.
Incision Site Study
My colleagues and I performed a study to compare the structure of clear corneal incisions using 1.8-mm C-MICS procedure in 30 eyes vs standard 2.8 mm coaxial phaco in a second group of 30 eyes. We imaged the incision structure with anterior segment optical coherence tomography (Visante OCT; Carl Zeiss Meditec, Dublin, CA) and evaluated corneal thickness, incision length, and angle of incision at 1 day, 1 week, 2 weeks, and 4 weeks postoperative. At 1 week, more eyes in the 2.8-mm group had endothelial gaping, Descemet
Figure 6. At 1 week, more eyes in the 2.8-mm group had endothelial gaping, Descemet membrane detachment, and endothelial side misalignment than those eye in the 1.8-mm group.
Figure 7. The corneal thickness returned to normal values during the first week postoperative in the 1.8-mm group, but took longer in the 2.8-mm group.
Figure 8. A sharper incision angle resulted in less trauma and corneal thickening at the wound site.
membrane detachment, and endothelial side misalignment than those eye in the 1.8-mm group. The corneal thickness returned to normal values during the first week postoperative in the 1.8-mm group, but took longer in the 2.8-mm group.
We also observed that the angle of incisions is important. A sharper incision angle resulted in less trauma and corneal thickening at the wound site supporting the theory that making longer tunnels provides more favorable outcomes.
Clinical Case
I have used C-MICS with good results in a variety of complicated cases. An example of such as case is a woman who had a previous 12-incision radial keratotomy and a cataract associated with severe zonular weakness. The 1.8-mm C-MICs incision fit well in between 12 incisions with no risk of incision enlargement or rupture during or after the procedure.
Figure 9. The 1.8-mm C-MICs incision fit well in between 12 incisions with no risk of incision enlargement or rupture during or after the procedure.
The capsulorrhexis was moving under the current of the irrigation aspiration, giving an idea as to the weakness of the zonular fibers. Because of this, I decided to proceed with a capsular tension ring to stabilize the bag and extend the equator. After stabilization, I implanted the Akreos MICS IOL. As the IOL is taken from its holder and placed in the transferring cartridge, the front and back of the IOL is easily identified.
Figure 10. As the IOL is taken from its holder and placed inthe transferring cartridge, the front and back of the IOL is easily identified.
Figure 11. The Akreos MICS IOL in the bag.
I used the wound-assisted technique to implant the IOL. Because of the excellent design of the Akreos, I only had to press lightly on the optic and the IOL was already in the bag
What is very good in this design is that you only have to slightly press on the optic and the lens is already in the capsular bag, obviating the need for special maneuvers for haptic implantation.
CLICK TO SEE DR. MALYUGIN PERFORM C-MICS ON A POST-RK PATIENT WITH CATARACT ASSOCIATED WITH SEVERE ZONULAR WEAKNESS.
Conclusion
Why should we perform C-MICS with
the Stellaris PC? First, we can use small incisions without changing our preferred technique. Smaller incisions are better because they promote less surgically induced astigmatism, less trauma and inflammation, leading to faster visual recovery.2 Secondly, C-MICS results in a high level of chamber stability. We can use high vacuum settings without compromising chamber stability, while maximizing the holding force to make emulsification more effective. C-MICS provides optimal wound protection around the sleeve and induces no leakage during or after the surgery. The thinner needle penetrates more easily into hard cores and in cases of small pupils, the ability to visually monitor the process is enhanced. Finally, C-MICS can be used effectively and safely for more complicated cases.
In my opinion, it is clear that advanced technology, such as the Stellaris PC, promotes an ongoing amalgam of efficiency and improved outcomes for both anterior and posterior surgeons.
Boris Malyugin, MD, PhD, is the Chief of the Department of Cataract and Implant Surgery, and the Deputy Director General of the S.Fyodorov Eye Microsurgery Complex State Institution, Moscow, Russia. Dr. Malyugin states that he is a consultant for Bausch + Lomb and Microsurgical Technology, Inc. He may be reached at +7 495 488 8511; fax +7 499 905 8051; or via e-mail at boris.malyugin@gmail.com.
1. Heng WJ. Surgically induced astigmatism in standard vs microincision coaxial phacoemulsification. Paper presented at the 11th Conference of the China Cataract Society; September, 2008; Xi'an, China.
2. Braga-Mele RM. Is smaller truly better? An evaluation of phaco incision size and astigmatism. Paper presented at the 2009 American Society of Cataract and Refractive Surgery meeting; April 3-8; San Francisco.
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