Modified adaptation of the twist-and-out technique for intraocular lens exchange

Abstract

Many methods can be used to explant an intraocular lens (IOL) after prior cataract surgery. Here, we describe a modified approach to the twist-and-out technique for IOL removal. The IOL is dissected and brought into the anterior chamber (AC), where 1 haptic is externalized. The adaptation in this technique occurs next; an additional paracentesis is made 180 degrees away from an adjacent side port, and the shaft of a 25-gauge cannula is threaded across the AC to connect these incisions. This maneuver frees both hands to use forceps within the incision, grasp the IOL, and rotate it around the forceps. The use of both hands allows for a smaller, more controlled movement than the original 1-handed pronation. The cannula shaft aids in twisting the IOL tightly around the forceps while protecting the corneal endothelium. The forceps-lens complex is then withdrawn, extracting the IOL whole with 1 efficient movement.

Certain circumstances may require intraocular lens (IOL) explantation after cataract surgery. These include dislocation, decentration, incorrect lens power, and undesirable photic phenomena, such as glare or optical aberrations.¹ The incidence of IOL removal with or without subsequent lens exchange was historically estimated at 2 per 1000 surgeries in Saudi Arabia but could readily be higher at present in the United States.² Nearly 4 million cataract surgeries are performed in the United States annually, and this number is expected to climb substantially as the population continues to age and life expectancy increases.³ Accordingly, more cases will require surgical removal after IOL implantation, most often due to late lens dislocation in addition to the other reasons listed above.⁴

Ernest first described intraocular folding to explant an IOL by using a spatula through a side-port incision to apply upward force on the underside of the optic and lens insertion forceps through the main incision to apply downward force over the optic. These opposing motions combined with a 90-degree rotation allow for the IOL to be refolded around the forceps and extracted through a 3.0 mm corneal incision.⁵ IOL exchange surgery has continued to evolve, producing various explantation techniques through increasingly smaller incisions. This movement has been aided by the introduction of microinstruments, such as intraocular scissors, forceps, and micrograspers, designed to facilitate controlled lens removal through small incisions while reducing the potential for associated anterior segment trauma.

Many different techniques may be used to remove an IOL. These include retraction of the IOL through a surgical wound or an IOL cartridge, cutting the optic into smaller segments and removing piecemeal, cleaving the haptics before retraction of the remaining optic, and rotational maneuvers to remove the entire IOL.^6–13 The method of IOL explantation that we aim to enhance with modification uses rotational manipulation of the lens called the twist-and-out technique. This technique externalizes the leading haptic and uses a spatula above the IOL to protect the corneal endothelium. Forceps are used to grip the IOL, and a rotational movement allows for rolling of the IOL around the forceps. Retraction of the forceps then explants the IOL through an incision as small as 2.2 mm.¹³ Here, we describe an adaptation of this technique to remove a foldable acrylic IOL.

SURGICAL TECHNIQUE

Case 1

A patient presented with a possible variant of dead-bag syndrome and a dislocated IOL through a posterior capsular break (Video 1, https://links.lww.com/JRS/A679). The decision was made to exchange the IOL. Two paracenteses were created with a 1 mm side-port blade, and the anterior chamber (AC) was filled with a dispersive ophthalmic viscosurgical device (OVD). The IOL was carefully dissected away from the capsular bag and prolapsed into the AC. Anterior vitrectomy was performed to free the IOL of any vitreous before extraction. The right-sided paracentesis was enlarged with a 2.4 mm keratome, and the IOL was positioned with 1 haptic in the main wound. A paracentesis was created 180 degrees away from the left-most paracentesis, and the shaft of a 25-gauge cannula was placed across the AC connecting these 2 incisions. Toothed 0.12 forceps were used to grasp and slowly twist the IOL counterclockwise, away from the hub of the cannula, using the cannula shaft placed across the AC to guide the IOL around the forceps while protecting the endothelium. Once the IOL was well-wrapped, the forceps were withdrawn and the IOL inspected to ensure complete removal. The 25-gauge cannula shaft was removed and OVD inserted to enlarge the sulcus. A 3-piece IOL was then inserted into the sulcus, OVD was removed with bimanual irrigation/aspiration, and the wounds were sealed.

Case 2

A patient presented for an IOL exchange after a large hyperopic surprise (Video 2, https://links.lww.com/JRS/A680). A paracentesis was created with a 1 mm side-port blade, and the AC was filled with OVD. A 2.4 mm keratome was used to create the main wound. The IOL was carefully dissected away from the capsular bag and prolapsed into the AC. The IOL was then positioned with the proximal haptic out of the main wound. A paracentesis was created 180 degrees away from the left-most paracentesis, and the shaft of a 25-gauge cannula was placed across the AC connecting these 2 paracenteses. The IOL was grasped with 0.12 forceps and slowly twisted clockwise, using the cannula shaft placed across the AC to force the IOL around the forceps while protecting the endothelium. Once the IOL was well-wrapped around the forceps, the forceps were withdrawn and the IOL was inspected to ensure complete removal. The 25-gauge cannula shaft was removed and cohesive OVD used to enlarge the capsular bag. A new single-piece IOL was then inserted into the capsular bag and the OVD removed with irrigation/aspiration. Intracameral moxifloxacin was injected into the AC, and the incisions were sealed (Figure 1).

Figure 1.: A: Preparing for the modified twist-and-out: The proximal haptic is externalized through the wound and the shaft of a 25- or 27-gauge cannula is placed across the anterior chamber connecting two 1 mm incisions created 180 degrees apart. b: The IOL is grasped with a forcep and rotated against the cannula and away from the hub (clockwise in this example). c: After 1 complete turn of the forceps. d: The IOL has been maximally wrapped around the forceps and is now ready to be removed after 2 complete revolutions, compared with the maximum single revolution possible with the unmodified technique. Note how the distal haptic maintains a planar orientation.

DISCUSSION

IOLs can be surgically removed by a variety of techniques. A commonly used method involves raising the IOL into the AC and cutting the optic and then removing these smaller fragments through the corneal wound. However, the incision size often must be expanded to extract the pieces, and the process of removing them may cause mechanical loss of corneal endothelial cells. Amputation of haptics and removing the optic only may be necessary in cases of capsule fibrosis.¹⁴ A method to explant the lens whole using toothed forceps was described by Henderson et al., but this method requires a larger 2.75 mm incision.⁹ Finally, refolding of the IOL can be performed in various ways. Bhaumik et al. used a wire noose to refold and load an IOL into a modified lens cartridge and then removed it through the main incision. Disadvantages of this method include that it cannot be used with thicker IOLs and it can be challenging, requiring a high level of surgical skill.⁷ A similar recently described technique uses forceps inserted through a D1 implantation cartridge that has been repurposed for extraction of an IOL. This method also allows retrieval of a lens that has descended into the vitreous cavity, without raising it above the level of the iris. However, removal by Fukuoka's cartridge pull-through is not suitable for withdrawal of rigid or hydrophilic IOLs, unless a specific pair of serrated forceps are used. Special attention must be paid to precisely grasp the IOL or else rotation of the haptics may cause endothelial cell or iris damage.⁸ By contrast, Pandit's twist-and-out method of refolding around standard forceps may be more easily reproducible and adds a layer of protection to the overlying corneal endothelium.¹³

Our simple modification of the twist-and-out technique may allow for wider adoption of this method because it replaces the large 1-handed pronation with a 2-handed approach. By using the shaft of a 25-gauge cannula from one side port to another, the surgeon still protects the corneal endothelium and provides a surface to roll the IOL against. This action requires creating a second paracentesis, which is a common practice in IOL exchange surgery and does not pose increased risk of postoperative complications. Spanning the cannula shaft across the AC eliminates the need to hold a spatula in the off-hand. This facilitates the use of both hands to easily rotate the forceps while gripping the IOL. The forceps may be rotated either clockwise or counterclockwise, as long as the rotation occurs away from the hub of the cannula. For instance, the forceps should be rotated clockwise if the hub of the cannula is located near the paracentesis on the left of the main wound and counterclockwise if the hub of the cannula is located nearest the right most paracentesis of the wound (Videos 1 and 2). Failure to rotate the correct direction may cause the cannula to retract into the AC, which could lead to endothelial damage. Using both hands allows for more precise control and additional rotations to be completed, thus rolling the IOL tighter around the forceps. This decreased circumference of the combined IOL and forceps allows the IOL to be extracted through an even smaller incision. Some IOLs may not exhibit the same ease of foldability, which increases the risk for enlargement of the corneal incision, and subsequent wound leak and residual astigmatism. When explanting less flexible lenses, the trailing haptic should be oriented in the planar position to minimize potential damage to the iris root. This adaptation has been successfully used on a range of acrylic lenses, including Clareon, AcrySof, Tecnis, and Envista IOL platforms. Overall, this modified technique is easy to reproduce, can be applied with a wide variety of IOLs, and uses surgical instruments that are readily available in most ophthalmology operating rooms.

WHAT WAS KNOWN

• Many methods have been described to explant an IOL and often require cutting the IOL into smaller pieces, or enlarging the main wound for retraction through the incision.
• The twist-and-out method for IOL removal was recently described using a large 1-handed rotational movement to extract an entire lens through a 2.2 corneal incision using forceps.

WHAT THIS PAPER ADDS

• This modification allows easily reproducible IOL removal with routinely available instruments and facilitates more precise control by allowing 2 hands to execute the twist, which may minimize potential complications during IOL explantation.