TECHNIQUE

Perfect Flanger forceps: standardizing flange creation for intrascleral intraocular lens fixation

Amado, Sebastian F. MD

Author Information
JCRS Online Case Reports 11(1):p e00089, January 2023. | DOI: 10.1097/j.jcro.0000000000000089
  • Open
  • Associated Video

Abstract

The intraocular lens (IOL) scleral fixation using the Yamane technique was introduced in 2014 as a 27-gauge double-needle technique and then in 2017 as a 30-gauge double-needle technique.1 Although it has become the surgery of choice for many surgeons when dealing with aphakia and no capsular support, there are significant challenges when learning this technique. The original technique has suffered multiple modifications in an attempt to simplify or standardize several steps.2–4 Another issue is the material composing the lens's haptics because some of them tend to kink or break more easily than others.5 Standardization in the construction of a suitable flange is essential to keep the IOL in good support and providing for a long-term stability. As was previously demonstrated, the distance between the forceps grip of the haptic and the end of the haptic during heating with a low-temperature cautery is a critical factor for obtaining an optimal flange shape. It has been described that a suitable flange should have a mushroom-like shape and double the diameter of the haptic to provide maximum hold in the scleral tunnel and minimum leak to the subconjunctival space.6 This was possible using a 0.5 to 1.0 mm distance from forceps haptic grasping to the end of the haptic during heating. It has been reported that there were no differences in flange diameters between 1.0 mm and 2.0 mm haptic melt lengths across different IOLs (no forceps were used), but different shapes were reported depending on the haptic material.7

THE INSTRUMENT

The Perfect Flanger (Rumex 4-211T) is a forceps made of titanium which has a 150 μm deep groove (75 μm for each arm) at the grasping end, combined with a 1 mm long reference cylinder attached to it (Figure 1). Having a grooved grasping end allows for a gentle way of holding the haptics, thus diminishing the possibility of an unwanted trauma. This is especially important when holding poly(methylmethacrylate) (PMMA) haptics, which tend to kink more easily than polyvinyl fluoride (PVDF) ones, making it impossible to continue the surgery in a safe manner when it happens.

F1
Figure 1.:
a: Perfect Flanger is a titanium-made forceps. b, c: The Perfect Flanger has a 150 μm groove, a 300 μm grasping end, and a 1 mm long reference cylinder.

In addition, having a 1 mm reference cylinder saves surgery time by sparing the need for several measurements with different tools such as a caliper, professional ruler, or ink markers to assure the correct distance between the haptic tip and the forceps holding it.

TECHNIQUE

A 2-port (infusion-vitrector) 23-gauge vitrectomy set is used. A core vitrectomy and a shaving of the vitreous base are performed. The midline is identified with marks made on the limbal conjunctiva at the 3 o'clock and 9 o'clock positions. Two small peritomies are created next to them. A second set of marks is made 2 mm from the limbus and then 2.5 mm inferior or superior to the first mark to identify the future path of the intrascleral tunnel nasally and temporally. A 3.2 mm corneal incision is made at the 12 o'clock position. A thin-walled 30-gauge needle (TSK Laboratory Japan) is then bent at the hub to approximately 70 degrees and placed on a tuberculin syringe. A gradable diamond is set at 400 μm for a previous scleral groove. With a Sinskey hook, start a scleral pocket, and while holding up the roof of the scleral pocket, the TW needle is introduced in it. This maneuver (coined by the author as the shoehorn technique) avoids engaging scleral tissue with the needle and securing the correct initial path depth. A 2.5 mm long, angled 5 to 10 degrees downward from the iris plane and 20 degrees from the limbus scleral tunnel is made at the 3 o'clock position. Once the needle is inside the eye, the previously loaded 3-piece IOL is partially inserted into the anterior chamber, injection is then paused, and the leading haptic of the IOL is directly threaded into the 30-gauge needle. The IOL optic is then completely injected into the anterior chamber, while the trailing haptic is left securely into the main incision. The needle is left inside the eye. A second 2.5 mm intrascleral tunnel is created with a second 30-gauge needle, 180 degrees from the first tunnel. A 23-gauge microforceps (Microsurgical Technology) is used from the main incision to guide the trailing haptic into the second 30-gauge needle. The needles along the haptics are then externalized, once at a time, being the trailing haptic first.

For a right-handed surgeon, usually, it is more comfortable to hold the Perfect Flanger forceps in his right hand and a microforceps or similar conventional forceps in his left hand (Figure 2, a). Next, the microforceps is used to gently slide the haptic through the groove of the Perfect Flanger until the 1 mm reference cylinder is matched, and the forceps is then closed to keep the haptic in place (Figure 2, b and c). Then, the surgeon slowly approaches a low-temperature cautery (Accu-Temp Cautery, Beaver-Visitec International) to its tip until the flange reaches the grasping end (Figure 2, d). The reference cylinder also acts as a pusher, allowing the flange to be buried inside the scleral tunnel using this portion of the Perfect Flanger, with no further instruments (Figure 3, a–d).

F2
Figure 2.:
a: Perfect Flanger in right hand and Kelman forceps in left hand (right-handed surgeon). b: Holding the haptic securely with a Kelman forceps while closing the Perfect Flanger arms. c: Match the haptic tip with the reference cylinder to ensure proper melting distance. d: Flange creation using a low-temperature cautery until the flange reaches the grasping end.
F3
Figure 3.:
ad: The reference cylinder also acts as a pusher to bury both flanges completely inside the scleral tunnels.

Both flanges, temporal and nasal, are created in the same fashion, care must be taken to a complete burying of the flanges into the scleral tunnels, avoiding subconjunctival exposure, and assuring IOL centration, assuming both scleral tunnels have been constructed with the same length and 180 degrees apart.

The Perfect Flanger was tested with 2 different haptic materials (PMMA and PVDF) and a 6-0 polypropylene suture (Video 1 Perfect Flanger, https://links.lww.com/JC9/A368). Photographs were taken for evaluating flange shape, and every flange diameter was measured using ImageJ software. Surgical time from haptic tip grasping until flange was buried into the scleral tunnel was also measured by film elapsed time.

When measured from top view, PMMA haptic mean flange diameter was 374 (±10) μm, PVDF haptic mean flange diameter was 447 (±12) μm, and 6-0 prolene mean flange diameter was 448 (±17) μm (Figure 4, a).

F4
Figure 4.:
a: Top view: PMMA haptic flange mean diameter was 374 μm, PVDF haptic flange mean diameter was 447 μm, and 6-0 prolene mean flange diameter was 448 μm. b: Lateral view: PMMA haptic mean flange diameter was 364 μm, PVDF haptic mean flange diameter was 438 μm, and 6-0 prolene mean flange diameter was 453 μm. PVDF = polyvinyl fluoride

Lateral measurement of the same flanges gave a PMMA haptic mean flange diameter of 364 (±11) μm, a PVDF haptic mean flange diameter of 438 (±6) μm, and a 6-0 prolene mean flange diameter of 453 (±6) μm (Figure 4, b). There were different shapes between different materials, PMMA flanges adopted an inverted cone shape, opposed to PVDF and 6-0 prolene flanges, which had a mushroom appearance.

The mean individual flange construction time, from the first grabbing and extrusion from the needle with a Kelman forceps until flange was completed, was 47 seconds. The mean individual flange construction time until a complete burying of that same flange was 1 minute and 17 seconds. The mean surgical time since the first haptic was grabbed and extruded from the needle until a complete burying of both flanges was 5 minutes and 14 seconds.

DISCUSSION

Severe capsular bag dislocation, a posterior capsular rent, and loss of lens fragments are, generally, uncommon complications during cataract surgery.8 Nevertheless, every anterior segment surgeon will face them at some point and should be prepared to manage different methods of placing and fixating an IOL.

Since its introduction in 2014, the Yamane technique has provided a safe and successful method of IOL fixation. As in most medical procedures, preparation and practice help to ensure efficient and sufficient surgical skills.

Precise and standardized surgical steps will improve IOL stabilization and refractive results. Today we have a myriad of tools such as the Yamane needle stabilizer or the “forceps-needle” as a useful instrument to make a more precise and standardized surgical technique.4,5

To our knowledge, there are no reports of a standardized way of making a flange. The Perfect Flanger forceps is intended to fill the gap between precise scleral tunnel construction and flange creation by adding a safe and reproducible method for melting the correct amount of IOL's haptic, aiming for a well-centered IOL.

Apart from all different techniques for intrascleral haptic fixation, the Perfect Flanger forceps could also be used for creating a flange with a 6-0 prolene suture when suturing iris, IOLs, and CTRs to the sclera.9,10 It could also improve the accuracy of how much suture is being heated, delivering a suitable flange diameter (not too big or small) avoiding dangerous exposures or asymmetries in tension adjustments.11

Further prospective studies are needed to prove the benefits of this new tool, but it is the author's belief that it serves as a useful and simple way of standardizing flange creation for intrascleral fixation techniques.

WHAT WAS KNOWN

  • The distance between the forceps grip of the haptic and the end of the haptic is a critical factor for obtaining an optimal flange shape.
  • There are no differences in flange diameters between 1.0 mm and 2.0 mm haptic melt lengths across different IOLs.
  • PMMA haptics tend to kink more easily than polyvinyl fluoride (PVDF) haptics.

WHAT THIS PAPER ADDS

  • The Perfect Flanger forceps allows for an accurate, simple, and reproducible method for measuring and melting a 1 mm haptic end.
  • A grooved grasping end forceps facilitates the surgeon not to put “excessive-pressure” on haptics avoiding the possibility of kinking the haptics (especially PMMA's).
  • Using the Perfect Flanger, mean flange diameters were 374 (±10) μm for PMMA haptics, 447 (±12) μm for PVDF haptics, and 448 (±17) μm for 6-0 prolene.

REFERENCES

1. Yamane S, Sato S, Maruyama-Inoue M, Kadonosono K. Flanged intrascleral intraocular lens fixation with double-needle technique. Ophthalmology 2017;124:1136–1142
2. Kim DB. Trailing-haptic-first modification of double-needle intrascleral haptic fixation technique. J Cataract Refract Surg 2018;44:424–428
3. Gelman RA, Garg S. Novel yamane technique modification for haptic exposure after glued intrascleral haptic fixation. Am J Ophthalmol Case Rep 2019;14:101–104
4. Amon M, Bernhart C, Geitzenauer W, Kahraman G. The forceps-needle: combining needle and grasping functions in a single instrument. J Cataract Refract Surg 2021;47:123–126
5. Besozzi G, Posarelli C, Costa MC, Montericcio A, Nitti G, Giancipoli E, L'Abbate M, Pignatelli F, Parolini B, Figus M. Standardized Flanged intrascleral intraocular lens fixation with the double-needle technique for cataract luxation in the vitreous chamber during phacoemulsification. J Ophthalmol 2021;2021:9998482
6. Kronschläger M, Blouin S, Roschger P, Varsits R, Findl O. Attaining the optimal flange for intrascleral intraocular lens fixation. J Cataract Refract Surg 2018;44:1303–1305
7. Ma KK, Yuan A, Sharifi S, Pineda R. A biomechanical study of flanged intrascleral haptic fixation of three-piece intraocular lenses. Am J Ophthalmol 2021;227:45–52
8. Lundström M, Brege KG, Florén I, Lundh B, Stenevi U, Thorburn W. Postoperative aphakia in modern cataract surgery: part 1: analysis of incidence and risks based on 5-year data from the Swedish National Cataract Register. J Cataract Refract Surg 2004;30:2105–2110
9. Kusaka M, Miyamoto N, Akimoto M. Repairing iridodialysis by riveting with a double-flanged polypropylene suture. J Cataract Refract Surg 2019;45:1531–1534
10. Canabrava S, Canêdo Domingos Lima AC, Ribeiro G. Four-Flanged intrascleral intraocular lens fixation technique: no flaps, no knots, no glue. Cornea 2020;39:527–528
11. Werner L. Flange erosion/exposure and the risk for endophthalmitis. J Cataract Refract Surg 2021;47:1109–1110

Supplemental Digital Content

Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of ASCRS and ESCRS
Data is temporarily unavailable. Please try again soon.