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Four-flanged intrascleral IOL fixation technique: Where are we?
The technique is used to fixate a non-foldable IOL, and research is underway on using a foldable IOL.
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In recent years, several IOL fixation techniques have been proposed. Nowadays the tendency is to evolve from time-consuming techniques that use knots and big incisions to easier, faster and sutureless techniques.
In the 1980s, Malbran and colleagues were the first to propose an IOL scleral fixation technique. They used a 10-0 polypropylene suture to fixate the IOL haptics to the sclera at 3 and 9 o’clock, 2 mm posterior to the limbus. In 1991, Lewis proposed the classical scleral fixation technique with scleral flaps, which guided and inspired more recent techniques. This technique is still used with good IOL stability and visual acuity results. The main complications observed include knot erosion, IOL tilting and decentration in the initial postoperative weeks and IOL dislocation due to suture breakage several months later. It happens because 10-0 polypropylene sutures are susceptible to degradation over time, which can lead to long-term IOL dislocation.
Source: Sergio Canabrava, MD, Ana Carolina Canedo, MD, Pedro Henriques Rezende, MD, Natan Halabi, MD, and Ana Clara Rezende, MD
Recently, Yamane and colleagues published a sutureless transconjunctival intrascleral technique, the elegant double-needle technique, which introduced the concept of the use of a flange created by a thermocautery tucked into the scleral wall for IOL fixation.
Also in 2017, inspired by Yamane, our group described a technique for subluxated cataracts. The technique was named the double-flanged technique and uses a 5-0 polypropylene haptic, which was initially removed from a three-piece IOL, to fixate the capsular bag to the sclera through a capsular tension segment. It was the first paper to propose the use of a flange at the opposite sides of the polypropylene monofilament in order to fixate a capsular bag through a capsular tension segment.
In 2019, we have proposed a novel sutureless scleral fixation technique, named the four-flanged technique, inspired by Lewis and based on Yamane’s flanged technique, using a 5-0 polypropylene suture, in order to simplify and improve the safety of scleral fixation using single-piece non-foldable IOLs. We would like to present the four-flanged technique and its evolution using a foldable IOL and show the stages of our research in this technique.
The four-flanged technique
When using the four-flanged technique in order to fixate a non-foldable IOL, we need to perform a 6-mm main incision by scleral tunnel or a cornea incision. After that, two 26-gauge hypodermic needles are used to performed two sclerectomies, each one 90° from the main incision. These needles work as an external guide to remove two pieces of 5-0 polypropylene suture from the eye. Then, we have two adjustable pieces of polypropylene suture in the main incision. Outside of the eye, the two polypropylene sutures ends are passed through the two eyelets of a non-foldable IOL (OP-72, Mediphacos) and heated by the thermocautery to create the first and second flanges. The first haptic of the IOL is then drawn into the eye using McPherson forceps while the other hand pulls the externalized suture to aid the correct positioning of the first haptic. Next, McPherson forceps are used to make a pronation movement in the second haptic while the surgeon uses the other hand to pull the other limbus externalized suture to aid the positioning of the second haptic in the sulcus. The IOL is centered using the two polypropylene suture ends externalized 2 mm from the limbus at each side. The sutures are cut 2 mm from their base and heated to form the third and fourth flanges, which will be inserted into the sclera (Figure 1).
Is it possible to reproduce the four-flanged technique using a foldable IOL?
The answer is yes. The basic steps would be the same as the technique with non-foldable IOLs. However, at this time, we are still defining the best strategy and steps to perform the technique with a foldable IOL. We have designed and created an IOL punch (Figure 2) to make two holes in the IOL, and through these holes the polypropylene sutures are fixated. The IOL haptics are then cut in order to prevent iridociliary touch and its possible complications. The first surgeries were performed using a vertical punch, and the holes were created in the vertical axis. After that, the technique steps are the same as for non-foldable IOLs (Figures 3 to 6).
Advantages
We believe that this novel technique simplifies, improves and quickens the IOL intrascleral fixation technique. It also has a low cost and gradual learning curve, as is based on classic scleral suture fixation techniques; however, unlike the Lewis technique, this approach does not require scleral flaps or knots. Furthermore, this technique overcomes the issue concerning the insertion of the trailing haptic in Yamane’s technique, which is the most challenging step of the procedure, as the 5-0 monofilament has a fully adjustable length.
Clinical application
An important question that arises is: Do we already recommend the use of the four-flanged technique with a foldable IOL? Not yet.
At this moment, we can say that the four-flanged technique with a non-foldable IOL is tested and approved. However, the IOL punch and the four-flanged technique with a foldable IOL is under study.
The next step is testing the technique in creating a hole in the horizontal axis, and the last step is to perform the technique using a foldable IOL specifically designed for this technique. However, as it is a novel technique, further studies, a greater number of cases and a longer follow-up are necessary to verify its safety and efficacy.
- References:
- Canabrava S, et al. Int Ophthalmol. 2018;doi:10.1007/s10792-017-0746-5.
- Cavallini GM, et al. Eur J Ophthalmol. 2015:doi:10.5301/ejo.5000652.
- Lewis JS. Ophthalmic Surg. 1991;22(11):692-695.
- Malbran ES, et al. Int Ophthalmol. 1986;doi:10.1007/BF00159844.
- Stem MS, et al. J Vitreoretin Dis. 2017;doi:10.1177/2474126417690650.
- Vote BJ, et al. Am J Ophthalmol. 2006;doi:10.1016/j.ajo.2005.09.012.
- Yamane S, et al. Ophthalmology. 2017;doi:10.1016/j.ophtha.2017.03.036.
- For more information:
- Edited by Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: aehl19c@gmail.com; website: www.dragarwal.com.
- Sergio Canabrava, MD, can be reached at Cataract Department, Santa Casa of Belo Horizonte 197, 1704 – Claudio Manoel Av. Belo Horizonte, Minas Gerais, Brazil; email: sergiocanabrava@hotmail.com.
Disclosure: Canabrava reports agreement royalties for the Canabrava Ring with AJL Ophthalmic, agreement royalties for the flanged CTS with Madhu Instruments and PCT pending patent about the four-flanged IOL.