Ihave been performing bimanual microincision cataract surgery (MICS) for more than 5 years. Currently I use incisions of 1.8 mm or less in 99% of cases. I prefer a variation of bimanual MICS that I call bimanual cool mini incision phaco (BICONI). The only patients in whom I do not use BICONI are those with dark brown nuclei.
Six years ago, I began using the Megatron phaco system (Geuder, Heidelberg, Germany), because the combination of its cool phaco mode and dual-linear footpedal, which separates control of aspiration and ultrasound, enables me to use less energy in the eye. Additionally, the disposable tubing of the Megatron needs less maintenance and lowers the risk of infection or toxic anterior segment syndrome compared with reusable tubing.
I find that I have more control using my second hand for irrigation, as the flow itself can be used to steer the masses in the direction I desire. It is almost a third hand for me.
Eyes treated with this technique behave better than those treated in coaxial mode. Additionally, chamber stability increases because much lower parameters are used, creating less flutter in the posterior chamber and perhaps as a result less macular edema, although this must be confirmed with clinical studies.
THE BICONI TECHNIQUE
With 1.8-mm incisions, my current parameters are very low. Phaco power (in cool mode) is always less than 55%, vacuum is 150 mm Hg in sculpting mode and never more than 250 mm Hg in high vacuum mode, and bottle height is typically 75 cm. My effective phaco time is almost always between 1 and 2.5 seconds. The phaco tip and irrigating handpiece I use each have a diameter of 0.9 mm (Figure 1). This allows me to easily exchange instruments if necessary. I have also tried using smaller phaco tips; however, I found that they were less effective for hard nuclei.
I have been transitioning from a temporal main incision of 1.8 mm to 1.4 mm, which I prefer to use for phacoemulsification of softer nuclei. As a result, I can use the same knife for the main incision as I do for the sideport. Before IOL implantation, however, I must enlarge the incision to 1.8 mm.
<-p>A video demonstration of BICONI is available at http://eyetube.net/?v=gisee. In this case presentation, I had to enlarge the incision beyond 1.8 mm to implant the Micro AY 123 (PhysIOL, Liége, Belgium; Figure 2), a spherical lens with a C-loop design. This was an early case of 1.4-mm BICONI, and therefore my parameters were not yet adjusted for the mature type of lens that we encountered. During the final phase of surgery, you will notice a blockage in the tubing due to low suction.
For implanting a toric lens, I derive great benefit from using the Surgery Guidance 3000 (SG3000; SensoMotoric Instruments, Teltow, Germany) to align the IOL. The next generation of this technology will project the axis of alignment inside the oculars of the operating microscope.
I prefer using BICONI because it increases anterior chamber stability and allows me to direct the nuclear mass toward the phaco tip using fluidics alone. BICONI can be implemented through a 1.8- or 1.4-mm incision; however, at this time the smaller incision must be enlarged to facilitate IOL implantation.
Robert J. Van Horenbeeck, MD, is president of the Belgian Society of Cataract and Refractive Surgery, the president of the Belgian Eye Laser Society, the Head of the Anterior Segment Department at the St. Augustinus Ziekenhuis Hospital, and is in private practice at Oogkliniek-Antwerpen, Antwerp, Belgium. Dr. Van Horenbeeck states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +32 3 239 6767; fax: +32 3 239 8300; e-mail: email@example.com.
- When irrigation is performed with the second hand, flow can be used to direct the nuclear pieces toward the phaco tip.
- An incision size of 1.4 mm may be appropriate for softer nuclei.