In this issue of Retina Today, Tamer H. Mahmoud, MD, PhD, discusses surgical pearls for managing retained lens fragments by pars plana vitrectomy and lensectomy with mixed gauges.
We extend an invitation to readers to submit pearls for publication in Retina Today. Please send submissions for consideration to Dean Eliott, MD (deliott@doheny.org); or Ingrid U. Scott, MD, MPH (iscott@psu.edu). We look forward to hearing from you.
— Dean Eliott, MD; and Ingrid U. Scott, MD, MPH
Many vitreoretinal surgeons would agree that in the era of microincision vitrectomy surgery (MIVS) there is little place for 20-gauge pars plana vitrectomy (PPV). However, because small-gauge phacofragmatomes are not commercially available, surgeons may consider creating at least one 20-gauge sclerotomy for retained lens fragments. In this article, I describe my approach to managing retained lens fragments.
TIME TO INTERVENTION
Although in some facilities it may be possible for an
available retina surgeon to remove dropped lens material
during cataract surgery, this approach is not the standard
of care. Studies comparing same-day intervention vs later
PPV have demonstrated similar results with both
approaches.1 The determination of timing and the nature
of the intervention should be made on a case-by-case basis
after discussion with the cataract surgeon. I try to find out
if the procedure was performed under topical, retrobulbar
block, or general anesthesia; how the patient responded;
the stage of the procedure just before the lens material
dropped; the status of the capsule; the estimated size of the
retained lens material; the steps taken after the fragments
dropped; whether an anterior vitrectomy was performed;
whether any instruments were used to try to remove the
lens material from the vitreous cavity; whether the patient
has a history of previous retinal detachment or treatment
for any ocular disease, such as macular degeneration or diabetic
macular edema; and the status of the fellow eye.
I examine patients 1 day after the cataract procedure to assess the clarity of the cornea and the degree of anterior segment inflammation and to measure intraocular pressure (IOP). I discuss the details of the PPV procedure and plan with the patient and family, including when it would be most suitable to operate, which is usually within a few days of the cataract procedure. Before PPV is performed, patients may need to be examined daily to determine if the frequency of eye drop administration should be adjusted to ensure optimal control of IOP and intraocular inflammation and to minimize corneal edema.
I examine patients 1 day after the cataract procedure to assess the clarity of the cornea and the degree of anterior segment inflammation and to measure intraocular pressure (IOP). I discuss the details of the PPV procedure and plan with the patient and family, including when it would be most suitable to operate, which is usually within a few days of the cataract procedure. Before PPV is performed, patients may need to be examined daily to determine if the frequency of eye drop administration should be adjusted to ensure optimal control of IOP and intraocular inflammation and to minimize corneal edema.
INITIAL STEPS
I routinely plan for a 23-gauge PPV and pars plana lensectomy
(PPL). A detailed discussion with the cataract surgeon
regarding the patient's age and the size and density of the
retained lens material should indicate whether a fragmatome
will be needed; however, I have it ready in any
event. Regardless of whether the fragmatome will be needed,
I begin with a three-port 23-gauge PPV. I do not like to
use a 23-gauge probe through a 20-gauge incision because,
as more vitreous is removed, increased outflow through
the 20-gauge sclerotomy may result in a non-closed system.
If infusion does not keep up with aspiration, ocular collapse
ensues. This would be compounded if there is leakage from
the cataract wound, so I always check the wound's integrity
at the beginning of the procedure, and I always add a 10-0 nylon suture at the cataract wound for retina procedures
that are performed within 2 weeks of cataract surgery, even
with a self-sealing wound. PPV manipulations may change
wound architecture, and wound leakage may predispose
some patients to choroidal detachment and even choroidal
hemorrhage.2 One can imagine the potential risk of using a
23-gauge vitrectomy probe through a 20-gauge sclerotomy
with increased outflow and a leaky cataract wound.
ANTERIOR SEGMENT
To minimize retinal traction, the vitrectomy probe is
advanced to the pupillary area to cut any bands of vitreous
in the anterior chamber connecting with posterior vitreous.
The probe is then rotated into the anterior chamber to
remove lens material and vitreous. If a sulcus posterior chamber
or anterior chamber IOL has been implanted, the probe
is rotated around the lens.
In some instances, the entire lens is subluxed but remains in the pupillary area, so that the infusion cannula cannot be visualized. In these cases, I use a secondary infusion line attached to a 23-gauge butterfly needle that I bend and introduce through one cannula with the vitrectomy probe in the other hand (Figure 1). If I need to use the fragmatome, I remove the 23-gauge cannula and make a conjunctival peritomy and a 20-gauge sclerotomy in that area. Although I always use cannulas for 20-gauge cases, I do not introduce the fragmatome through a metal cannula because doing so may burn the sclera.
The secondary infusion hydrates the lens and makes it easier to remove. The needle tip helps bring the lens pieces into the fragmatome and prevents slippage into the posterior segment (Figure 1). The primary infusion is opened as soon as the cannula can be visualized, which keeps adequate balance between inflow and outflow. Most of the lens can be removed in this way, followed by bimanual removal of the capsule with retinal forceps and a probe. The assistant can help the surgeon by depressing the sclera all the way around to allow visualization of the edges of the capsule to confirm complete removal. If an assistant is not available, one cannula can be plugged and the surgeon can depress with one hand and remove the capsule with the forceps in the other hand.
POSTERIOR SEGMENT
Next, I focus on the posterior segment. Initially, I try to
visualize the dropped lens fragments and their relation to the
vitreous and determine the status of the posterior hyaloid. A
core vitrectomy is performed. The fragmatome should not
be used unless almost complete vitrectomy is achieved, to
avoid unnecessary traction that can lead to retinal breaks. I
begin by inducing a posterior vitreous detachment (PVD). It
may deceptively appear that there is a PVD because some
floating lens material comes to the probe tip with vitreous
and simulates the motion of a detached hyaloid. Triamcinolone
may be injected to help visualize the hyaloid.
However, I have found that the presence of lens material in
these patients provides good delineation of the hyaloid and
no additional visualization aid is needed.
A very adherent hyaloid may be managed with a bimanual technique. A 25- or 29-gauge chandelier can be introduced separately (Figure 2). I prefer 29-gauge because it provides adequate illumination and does not leak when removed. In my experience, the wound frequently requires suturing after removal of a 25-gauge chandelier. A pick can then be used in conjunction with the soft tip to detach the hyaloid. Another option when a 20-gauge sclerotomy is needed for the fragmatome is to use a 20-gauge lighted pick with the 23-gauge soft tip.
After detaching the hyaloid, one should focus on completing the PPV and not on the lens material that continues to come to the probe tip. At this stage, most of the lens fragments will be completely free in the vitreous cavity, and the fragmatome may be used to remove them. I like the linear aspect of fragmentation. Initially, I approach the lens piece without suction, and when I am almost touching it I start slow suction until I achieve occlusion. I then increase the suction and move the piece away from the retina and start the fragmentation.
I maintain some suction when I stop the fragmentation to keep the piece at the probe tip and not lose it back on the retinal surface. Because the fragmatome is 20-gauge, it may be necessary to increase the infusion pressure through the 23-gauge infusion line to keep up with the suction. Once most of the large, hard nuclear pieces are removed, I switch back to the vitrectomy probe, keeping it in the center of the vitreous cavity and increasing the suction so that the floating small nuclear and cortical material can come to the tip for removal. At this point, it is safer to switch to a soft-tip active suction cannula to remove the material that is left on the surface of the retina. The infusion pressure should continue to be higher when using 23-gauge instrumentation through a 20-gauge sclerotomy.
One of the most important steps of the procedure is a 360° exam with scleral depression to remove any residual lens material and check for peripheral breaks. I carefully remove almost every small piece in the vitreous base area (Figure 3). If they are not removed, these pieces can lead to residual persistent chronic inflammation with cystoid macular edema (CME). Breaks should be treated carefully with three contiguous rows of endolaser photocoagulation. A retinal detachment related to breaks may prevent good laser uptake, and fluid-air exchange may be required with complete flattening of the retina for good laser treatment. Careful shaving of the vitreous base is required if any breakrelated retinal detachment is seen, and the patient may require intraocular gas, preferably a short-acting gas such as non-expansile sulfur hexafluoride.
IOL CONSIDERATIONS AND CLOSURE
Most patients seen at our practice have had a sulcus lens
implanted at the time of cataract surgery. Care should be
taken during PPV not to remove the capsular support. Patients with good visual potential who were left aphakic
at the time of cataract surgery could benefit from IOL
implantation at the time of PPV/PPL. This should be part
of the preoperative discussion, and measurements for lens
implantation should be available. I prefer to place an anterior
chamber lens in most of these patients because longterm
complications are minimal with the new designs.
Secondary IOL implantation is another option, especially
with a complex PPV/PPL with retinal detachment and
intraocular gas injection.
After careful examination of the periphery with scleraldepression, the cannulas are removed and all leaking sclerotomiesare sutured. The 20-gauge sclerotomy is sutured with7-0 vicryl, and the conjunctiva in that area is closed with 6-0plain gut. I routinely give patients a posterior sub-Tenon triamcinoloneinjection to help control inflammation andsuppress any possible CME. This may also help decrease theburden of frequent drop administration early in the postoperativeperiod.
CONCLUSION
Methods of managing retained lens fragments after
cataract surgery are continuously evolving in the era of
MIVS. Careful patient history and surgical planning are
needed. Comfort with the use of mixed gauges in one
procedure, consideration of the proper choice of instruments,
and familiarity with bimanual technique and illumination
options are all important factors in achieving a
good final outcome.
Tamer H. Mahmoud, MD, PhD, is an Assistant Professor in the Department of Ophthalmology and Program Director of the Vitreoretinal Fellowship at Kresge Eye Institute, Wayne State University, in Detroit, MI. Dr. Mahmoud states that he has no financial interest in the material presented in this article. He may be reached at tmahmoud@med.wayne.edu.
Dean Eliott, MD, is Professor of Ophthalmology and Director of Clinical Affairs, Doheny Eye Institute, Keck School of Medicine at USC, and is a Retina Today Editorial Board member. He may be reached by phone: +1 323 442 6582; fax: +1 323 442 6766; or via e-mail: deliott@doheny.org.
Ingrid U. Scott, MD, MPH, is Professor of Ophthalmology and Public Health Sciences, Penn State College of Medicine, Department of Ophthalmology, and is a Retina Today Editorial Board member. She may be reached by phone: +1 717 531 4662; fax: +1 717 531 8783; or via e-mail: iscott@psu.edu.
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