Fixation for Delayed Bag-IOL Subluxation—When and How






CHAPTER


14


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FIXATION FOR DELAYED BAG-IOL SUBLUXATION


WHEN AND HOW


Tyler Q. Kirk, MD; Michael J. Siegel, MD; and Garry P. Condon, MD


Since the introduction of continuous curvilinear capsulorrhexis in the 1980s, late in-the-bag intraocular lens (IOL) subluxation, especially in pseudoexfoliation, has been reported with increasing frequency.15 Advancements in surgical technique and the development of new devices, such as standard and modified capsular tension rings, capsular segments, capsular hooks and retractors, as well as intraocular microsurgical instrumentation, provide an array of options to place an IOL securely in the capsular bag.68


As a result of the improved technology, cataract surgeons are often able to safely place the IOL entirely within the capsular bag in more complex cases. However, despite successful placement of the IOL in the capsular bag, a number of patients will experience subluxation of the capsular bag-IOL complex months or even years later. Although minor degrees of subluxation may be associated with no visual symptoms, substantial degrees of subluxation or dislocation may be associated with lenticular astigmatism, glare, dramatically reduced vision, inflammation, or elevated intraocular pressure (IOP).


In cases with symptomatic or poorly tolerated subluxation, surgical intervention is generally indicated. In cases of subluxation with minimal or no visual symptoms, it can be difficult to determine the need and timing for surgical intervention. If a minimally invasive approach were available, early intervention might be advantageous in stabilizing the capsular bag-IOL complex and avoiding further subluxation or dislocation that would require a more invasive and riskier surgical treatment.


In-the-bag IOL subluxation is most commonly associated with pseudoexfoliation, but other conditions such as trauma and vitreoretinal surgery can lead to this complication.1,2,9,10 A variety of methods for revising bag-IOL dislocation have been described; recent methods have specifically addressed in-the-bag subluxation.13,1119 Approaches to delayed in-thebag subluxation are discussed in Chapter 2. The first is a simplified and minimally invasive method for repositioning and iris-fixating mild in-the-bag IOL bag subluxation.20 The ideal candidate for this approach is generally a patient with an inferior planar subluxation with a fibrotic anterior capsulorrhexis edge whose visual symptoms may not yet warrant a surgical approach (Figure 14-1). The second is a simplified technique for ab externo scleral suture fixation for late in-the-bag IOL subluxation in pseudoexfoliation that was a modification of a technique reported by Chan et al.15,19 With this technique, an iris hook is used for intraocular suture retrieval under direct visualization to minimize IOL and haptic manipulation and avoid the need for “needle docking.”19


Iris Suture Fixation Technique for Delayed Bag-IOL Subluxation


This surgical approach for iris fixation of delayed in-thebag IOL subluxation was first performed in patients with pseudoexfoliation glaucoma who required filtering surgery.20 The technique was employed during planned glaucoma surgery when a concurrent subluxation of the capsular bag-IOL complex was identified in the absence of related visual symptoms. This technique was later used in cases of moderate and more substantial subluxation associated with reduced vision. The first case was done under topical and intracameral anesthesia because it was unplanned; subsequent cases were done using a retrobulbar block. The main goal of this surgical approach is to minimize conjunctival and scleral manipulation.



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Figure 14-1. The subluxated IOL on presentation.




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Figure 14-2. A Sinskey hook engaging the anterior fibrotic capsular edge.




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Figure 14-3. The microforceps grasping the anterior capsule edge while engaging the midperipheral iris with a long curved needle.




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Figure 14-4. Long curved needle passed through anterior edge of capsule, ready to be routed back around fibrotic capsule edge.


The basics of the technique are as follows. Topical tetracaine 10.0%, tropicamide 1.0%, and phenylephrine 2.5% ophthalmic drops are applied 30 minutes before surgery. A 5-mL retrobulbar block of a 50:50 mixture of lidocaine 2.0% and bupivacaine 0.75% is administered under monitored anesthesia care. Superotemporal and superonasal limbal stab incisions are created with a diamond blade at approximately 10 and 2 o’clock. Following this, a dispersive sodium hyaluronate ophthalmic viscosurgical device is injected to provide anterior chamber stability and to hold vitreous posteriorly during IOL manipulation. If vitreous is noted in the anterior chamber, a limited 23-gauge anterior vitrectomy can be performed to free the IOL and capsule from vitreous entanglement. One must be careful not to excise or cut the fibrotic edge of the anterior capsulorrhexis rim, which will be used to secure the subluxated IOL-capsule complex. If a significant amount of vitreous is present and a significant anterior vitrectomy is required, the technique is less likely to be successful.


After the capsular bag-IOL complex is freed from any vitreous entanglement, a Sinskey hook or a pair of microsurgical forceps is placed through a paracentesis to engage the fibrotic edge of the anterior capsulorrhexis and capsule rim (Figure 14-2). The capsular bag-IOL complex is then gently engaged to see if it can be freely pulled superiorly toward its original position. If it is sufficiently mobile, the nondominant hand continues to hold the capsule in place while a 10-0 polypropylene single-armed suture on a long curved needle (PC-7; Ethicon) is passed through the other paracentesis into the anterior chamber with the dominant hand (Figure 14-3). A modified McCannel suture21 is then attempted in which the needle is carefully routed into and through the midperipheral iris into the sulcus, where it engages the fibrotic capsulorrhexis rim that is being held in place by the intraocular forceps (Figure 14-4). The suture is directed back around the fibrotic superior rim of the capsule and up through the midperipheral iris (Figure 14-5). In essence, the surgeon hooks the suture around the fibrotic edge after initially penetrating just above it on the first needle pass. The intraocular forceps can be used to guide the needle as it passes up through the iris and externally out the second paracentesis.



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Figure 14-5. Long curved needle wrapped around fibrotic capsule edge and back out midperipheral iris.




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Figure 14-6. Injecting carbachol to achieve pupil miosis and better secure the IOL.




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Figure 14-7. Intraocular snare retrieving distal suture end in preparation for Siepser knot.




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Figure 14-8. Externalization of the distal suture end with snare.




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Figure 14-9. Tying the modified Siepser knot.


At this point, the needle and suture should be outside the eye; the needle is cut off, leaving sufficient suture length to allow an intraocular slip knot to be placed. Some manipulation of the capsular bag-IOL complex with the intraocular forceps may be required using the previously placed suture to safely hold the complex in a more centered position for permanent suture fixation. When the IOL appears well centered and in a desirable position, an intraocular miotic is given to induce pupillary miosis (Figure 14-6). The intraocular suture snare (MicroSurgical Technology) is then used to retrieve the suture in order to tie a modified Siepser knot2225 that carefully secures the IOL and fibrotic capsule to the underside of the iris (Figures 14-7 through 14-9). The knot is secured with 2 additional throws and then cut intraocularly with microscissors. Following the knot placement, the superior pupillary margin can be retracted slightly superiorly. The intraocular microforceps can be used to gently pull the superior margin inferiorly to help create a more rounded pupillary appearance. If any vitreous has presented, a limited 23-gauge anterior vitrectomy should be performed to prevent any traction on the now-centered IOL from causing postoperative complications (Video 14-1). In these situations, we recommend a small peripheral iridectomy to prevent postoperative pupillary block.



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Figure 14-10. Needle engaging capsule from inferior approach.




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Figure 14-11. Needle through capsule, midperipheral iris, and exiting through peripheral cornea.




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Figure 14-12. Second needle from inferior approach through midperipheral iris 2 clock hours away and exiting peripheral cornea.




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Figure 14-13. Snare through paracentesis retrieving suture in preparation for Siepser knot fixation.




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Figure 14-14. Centered IOL with fixation suture in midperipheral iris.


In cases where the capsule of the subluxated IOL is not as robust, an inferiorly directed approach to this fixation strategy may be most successful and atraumatic. Create a paracentesis at 6 o’clock and pass one end of the double-armed 10-0 polypropylene suture on a long curved needle through this site until it engages first the superior capsulorrhexis edge (Figure 14-10), then passes through midperipheral iris, and finally exits out through peripheral cornea (Figure 14-11). The second needle pass goes through the same inferior paracentesis, up through superior midperipheral iris 2 clock hours away from the first pass, and out through peripheral cornea (Figure 14-12). The needles are cut with the suture ends left long and retrieved through the 10 and 2 o’clock paracenteses so that a Siepser sliding knot can be tied to secure and center the bag-IOL complex (Figures 14-13 and 14-14 and Video 14-2).


Patients with inferior planar IOL subluxation and a fibrotic anterior capsulorrhexis edge (see Figure 14-1) present a unique type of late in-the-bag IOL subluxation that has allowed successful application of this new technique. This method avoids other, more complex IOL suturing techniques such as scleral fixation, full iris-haptic fixation, or IOL exchange with anterior chamber IOL (ACIOL) placement. This technique is unique by being minimally invasive and avoidance of intraocular manipulation. Experience with passing McCannel sutures and tying Siepser knots are key to maintaining the minimally invasive nature of this technique.2125


As with all IOL-iris fixation techniques, the usual concerns such as long-term IOL stability with polypropylene suture use, pigment dispersion or uveitis-glaucoma-hyphema (UGH) syndrome, and cystoid macular edema (CME) exist. The concern about long-term stability of the polypropylene suture may be alleviated by the fact that these patients are often relatively older when the subluxation occurs, and this type of suture material might be sufficient for their lifespan. CME is of particular concern because it has been reported to be the most common cause of postoperative visual acuity decrease in iris- and scleral-fixated IOLs.26 As noted in previous studies, CME rates with iris-fixated IOLs are equal to or lower than the CME rates with scleral fixation and open-loop ACIOLs.12,26 We have not observed significant iris chafing or UGH syndrome with this technique. This might be because these patients already had a loose capsular bag-IOL complex with ample prior opportunity for posterior iris trauma and pigment loss, which is often seen prior to fixation intervention. Thus, the risk for developing UGH may actually be less than if one elects not to intervene. Prior evidence, well summarized by Wagoner et al26 in their IOL technology assessment for the American Academy of Ophthalmology, showed that although these are possible risks, iris-sutured IOLs were equally safe and had outcomes similar to those with scleral-fixated posterior chamber IOLs (PCIOLs) and open-loop ACIOLs.


Due to iris manipulation and the possible need for a more complex surgical technique, a retrobulbar block provides a more stable operative setting in our experience. However, topical and intracameral anesthesia may suffice. We have not witnessed any postoperative infections using this technique, and the risk of endophthalmitis should equal that of any other IOL procedure that does not involve scleral manipulation or fixation.27,28 No postoperative refractive changes due to the IOL repositioning have occurred in our cases, and the corrected distance visual acuity in each patient either improved or remain unchanged. There were no documented complications relating to IOP elevation, hyphema, corneal decompensation, or retinal detachment during the follow-up period. Many patients with late in-the-bag IOL subluxation have significant ocular comorbidities, and consideration of these, particularly pseudoexfoliation, are key to optimal patient outcomes.25,1013


For patients presenting with a late in-the-bag, straight inferior subluxation with minimal vitreous presentation and a moderately fibrotic anterior capsular, this simplified IOL repositioning technique is less traumatic and invasive than previously described methods.



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Figure 14-15. Dislocated in-the-bag IOL prior to scleral fixation.

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Jan 13, 2020 | Posted by in OPHTHALMOLOGY | Comments Off on Fixation for Delayed Bag-IOL Subluxation—When and How
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