This article is more than 5 years old. Information may no longer be current.
Sliding internal knot technique useful for late IOL dislocations
This technique has an advantage because of the external approach of the needle.
Click Here to Manage Email Alerts
Capsular bag IOL subluxations are a nightmare. With time, many IOLs are dislocated, and managing them is a headache. My special guest in this column is Thomas Oetting, who has devised a sliding internal knot technique to handle such cases.
Amar Agarwal, MS, FRCS, FRCOphth
OSN Complications Consult Editor
Late dislocation of the IOL is an increasingly common problem, especially in patients with pseudoexfoliation. Janet Tsui, Alton Szeto and I recently described a technique using a sliding knot for late dislocation that we have found useful for most types of IOLs. Our technique adapts from the previously published techniques of McCannel, Siepser, Chang, Oshika and Hindman. This technique has the advantage of an external approach of the needle with a sliding internal knot (SLIK) that does not require coverage or rotation.
Technique
The SLIK technique starts with conjunctiva dissections 180° apart to allow exposure of the sclera in the area of the sulcus close to the location of the IOL haptics. Retracting the iris with a hook may increase exposure of the haptics to ease suturing.
A 9-0 double-armed Prolene suture on a long curved needle is passed from the outside through the sclera about 1.5 mm posterior to the limbus under the haptic, through the capsular bag and out through the cornea, avoiding the iris (Figure 1). The other needle arm passes just over the haptic, under the iris and then again out through the cornea (Figure 2). One side of the suture is pulled with a hook through a paracentesis convenient to the surgeon (Figure 3). A loop of suture is pulled out through the same paracentesis (Figure 4). This leaves a loop and a free end through the same paracentesis, similar to that described by Siepser for iris repair or Chang for haptic fixation to the iris. The suture loop is wrapped around tying forceps, which in turn grabs the free end of the suture (Figure 5). The free end is pulled through the wrapped suture, and then forceps pull the other free end to slip the knot into the anterior chamber (Figure 6). Microforceps are used to snugly cinch down the knot to the sclera. Usually both haptics are tied down to fully secure the IOL. It is important to cut the suture close to the knot so the free ends do not irritate the iris.
Figure 1. Initial pass of the double-armed 9-0 Prolene suture goes under the haptic and through the capsule.
Figure 2. The other arm of the 9-0 Prolene suture is passed over the haptic, avoiding the capsule.
Images: Szeto A, Oetting TA
Figure 3. One end is pulled completely through the paracentesis.
Figure 4. The loop from the other end is pulled through the same paracentesis.
Figure 5. Suture from loop is wrapped around forceps, and the free end is pulled through and tied using the Siepser sliding knot.
Figure 6. Intraocular forceps are used to cinch down the knot to the sclera.
Complications
We described a few complications with the SLIK procedure in our review. In two patients, vitreous hemorrhage from the scleral passes led to a temporary decline in vision after the procedure, but this resolved without intervention. We also reported some temporary inflammation from irritation from suture ends that were not cut short enough, and this also resolved with limited intervention. We have used this technique on both three-piece and single-piece acrylic IOLs.
Conclusion
When the IOL is unstable, the external approach of the needle passes is easier than other techniques that we have tried. Additionally, the internal knot eliminates the need for a scleral flap to cover an external knot.
A video of the SLIK technique can be found at http://www.facebook.com/video/video.php?v=371436406140.