YAMANE DOUBLE-NEEDLE INTRASCLERAL HAPTIC FIXATION

MY TECHNIQUE

Steven G. Safran, MD

My variation of the Yamane double-needle intrascleral haptic fixation technique is based on the things I have learned from many years of experience with other methods of scleral fixation, including suturing and intrascleral haptic fixation in tunnels. The Yamane method simplifies intrascleral haptic fixation, but there are surgical concepts in common with all of these methods that surgeons should keep in mind when approaching these cases. The concepts I have found most important are as follows:

1. Working in a closed system. It is always important to work in a closed system with infusion control to maintain visibility and control of the ocular contents. Creating self-sealing incisions that do not leak during surgery is critical to maintaining control of the eye, and I prefer to use an infusion line on foot pedal control to apply infusion when needed to keep the pressure in the eye physiologic at all times. Hypotony during surgery is your enemy as it will reduce visibility and increase the risk of bleeding and of choroidal detachment. A pars plana infusion cannula has the specific advantage of providing better visibility during anterior chamber maneuvers (no distortion of the cornea) and less turbulence in the anterior chamber, which allows you to maintain viscoelastic in the anterior chamber. I prefer to control the infusion with a foot pedal rather than leave it on all the time because there are moments in the surgery where it is better to have the infusion off to prevent iris and viscoelastic from prolapsing through the incisions. If one is not comfortable with pars plana trocar placement, then an anterior chamber infusion line can and should be placed instead.
   
2. Performing an adequate and controlled vitrectomy. It is critical to do an adequate vitrectomy to avoid vitreous traction prior to doing complex maneuvers like docking haptics into needles. If the eye has not previously been vitrectomized, I recommend doing a pars plana anterior vitrectomy as this is the only way to ensure that the space you are working within has been adequately cleared. You will be working behind the iris so the vitreous must be completely removed from this space prior to other manipulations. Familiarizing oneself with pars plana anterior vitrectomy techniques will also make the surgeon much more comfortable with doing maneuvers behind the iris plane, which is where many of the steps in Yamane double-needle intrascleral haptic fixation are performed.
   
3. Protecting the corneal endothelium. Minimizing anterior chamber flow and the use of dispersive viscoelastic to protect the cornea endothelium are critical to avoid transient or permanent postoperative corneal edema. Dispersive viscoelastic can only be placed in a manner that protects the cornea when there is a “backboard” to inject against to support it. If the eye is not vitrectomized or if an intraocular lens (IOL) is present, dispersive viscoelastic can be injected at the beginning of the procedure. If the eye is vitrectomized and aphakic with a well-dilated pupil, injected viscoelastic will simply fall posteriorly and will not coat or protect the cornea. If the pupil is not widely dilated, one may often successfully use the iris to support the viscoelastic by starting the injection deep in the angle and working around the angle and then toward the center to create some endothelial protection and viscosity in the anterior chamber to “slow things down.” In vitrectomized aphakic eyes you can place the viscoelastic right after the IOL has been injected into the anterior chamber and use the IOL as a backboard to inject the viscoelastic against to support it and allow coating of the endothelium. Infusion should be off during viscoelastic injection.
   
   
   

   

   
   

   Figure 47-1. Marks are placed exactly 180 degrees apart for 30-gauge needle entry into the eye. Trocar for infusion is placed out of the way of surgical maneuvers. The hatched line demonstrates that marks for needle entry are exactly 180 degrees apart, and this line connecting them passes through the center of the cornea.

   
   
4. Fixating the haptics exactly 180 degrees apart and at the same distance from the limbus on each side is critical to achieving good centration without tilt. I always try to scleral fixate IOLs in the ciliary sulcus, which is just posterior to the root of the iris. Usually this is about 1.5 to 2 mm posterior to the limbus in my experience. The distance from the limbus to the ciliary sulcus varies depending on the meridian one is working on so I tend to go about 2 mm back if placing the haptics at a vertical meridian (12 to 6 o’clock). However, as I move toward more horizontal haptic placement I tend to place the needle passes a little closer to the limbus (1.5 mm). In some cases the surgeon has made a 12 o’clock incision to remove the IOL and will find it easier to place the haptics closer to the horizontal meridian, in which case I will place my marks for needle passes a little closer to the external limbus, 1.5 mm rather than 2 mm.

Place needle entry marks about 2 mm posterior to the limbus exactly 180 degrees apart at approximately 8:30 and 2:30. I only mark the external point of entry for the needle on each side. A straight instrument or suture connecting the 2 marks should pass through the center of the cornea. I place the mark on left side of the eye a little closer to the main incision than the mark on the right side of the eye to provide a better angle for docking the haptics into the needles later on. The pars plana trocar for infusion is placed 3.5 mm posterior to the limbus and out of the way of your work. If the eye has not been previously vitrectomized, a second pars plana trocar for the vitrector is placed in another quadrant. Paracenteses are ergonomically placed so that you have the best angle to access the haptics when you enter with microforceps to grab them. The main incision is placed slightly to the right of midline for a right-handed surgeon using a 2.75-mm keratome (Figure 47-1).

STEP 2: INSERTION OF IOL INTO THE ANTERIOR CHAMBER

After injecting a 3-piece lens into the anterior chamber, the IOL is now sitting on top of the iris with the trailing haptic left out of the eye. This is a good time to inject some dispersive viscoelastic to protect the cornea as you now have a backboard to inject against so the viscoelastic will not fall into the back of the eye.

STEP 3: INSERTION OF FIRST 30-GAUGE TSK NEEDLE AND DOCKING OF DISTAL HAPTIC

The first 30-gauge TSK needle is inserted on the left side through the previously placed scleral mark entering at about a 20-degree angle to the sclera and parallel to the limbus. A tunnel-through sclera about 1.5 to 2 mm long is created before redirecting the needle to a more acute angle and diving into the eye just under the iris. If the iris is engaged, then the needle should be withdrawn and a second attempt made slightly more posterior. The infusion line should be on during this maneuver to firm up the eye and provide counterpressure, making it easier to control the path of the needle through the wall of the eye. It is not advisable to pass the needle when the eye is hypotonous (Figure 47-2).

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