36
QUESTION
WHEN SHOULD CATARACT SURGERY BE PERFORMED IF A VITRECTOMY IS PLANNED—BEFORE, DURING, OR AFTER?
Michael I. Seider, MD
Amar Patel, MD
There are many factors to consider when deciding to take a patient to the operating room for either pars plana vitrectomy (PPV) and/or cataract surgery. Do the risks outweigh the benefits? Does the patient really need surgery now, or can he or she wait? Surgical decision making has increased complexity when you have a patient who needs a vitrectomy, but also has a cataract. This chapter attempts to clear up some of the potential questions regarding this clinical scenario and provide a real-world rule-of-thumb algorithm for your next patient.
Performing Phacoemulsification and Intraocular Lens Implantation Before Pars Plana Vitrectomy
PROS
MAJOR
- As a general rule, PPV is more easily performed in a pseudophakic eye. The vitrectomy cutter can cross the midline to remove contralateral vitreous without phakic lens damage, the vitreous base can be more thoroughly shaved, the light pipe can be brought across midline to achieve improved visualization, and the view is usually clearer as the surgeon does not need to look through the cataractous crystalline lens.
- This approach allows for cataract surgery to be performed with an intact vitreous body and without the lens hardening that occurs following PPV, possibly reducing complication rates.1
- In cases of epiretinal membrane (ERM), performing the cataract surgery beforehand may achieve improved visual function without the need for PPV/membrane peeling.
- This approach allows for cataract surgery to be performed with an intact vitreous body and without the lens hardening that occurs following PPV, possibly reducing complication rates.1
MINOR
- By performing cataract surgery first, you can learn about patient’s tolerance of monitored anesthesia care during intraocular surgery.
CONS
MAJOR
- The caveat to PPV being easier in a pseudophake is that it is only true if the cataract surgery is done properly and without significant complication. If no suture is placed in the main corneal wound during cataract surgery (or by the retinal surgeon at the beginning of the PPV), the anterior chamber can burp during port placement or scleral depression, flattening the anterior chamber and possibly resulting in intraocular lens (IOL) decentration or even dislocation. Another way to prevent IOL dislocation out of the bag during PPV is performing cataract surgery with a small capsulorrhexis. A small rhexis, if opaque, however, can lead to decreased intraoperative visualization during PPV. Certain cataract surgery complications may seriously impair achievement of retinal goals. Consider the situation of a dropped crystalline lens or IOL enmeshed in vitreous atop a traction retinal detachment!
MINOR
- If posterior capsular opacification develops behind the IOL, this may require surgical posterior capsulectomy during PPV, which may destabilize the recently inserted IOL.
- Condensation or fogging on the posterior surface of the optic may occur if the posterior capsule is open; however, such condensation is often readily counteracted with wiping by the soft tip or the use of viscoelastic.
- If a patient has a scleral buckle placed or a silicone oil tamponade used (that is expected to be permanent) during PPV, the IOL power placed during the initial cataract surgery will have an incorrect power. It is not always possible to predict precisely what procedures will be performed during PPV.
Cataract Extraction With Intraocular Lens Implant During Pars Plana Vitrectomy
- Combined single-surgeon phacovitrectomy is often performed in Europe and in some places in the United States.2 Two-surgeon phacovitrectomy is much more common in the United States, with an anterior segment surgeon performing the cataract surgery in the same surgical session just prior to or following PPV.
- The feasibility and success of a combined technique depends highly on the level of skill of the retinal surgeon or the availability of a trusted anterior segment colleague. Indeed, combined surgery may be the most desirable approach for many patients, but logistical and competition-related concerns may be in the way.
PROS
MAJOR
- With combined cataract surgery and PPV, patients only need to go under the knife once, which saves time and money. Although safety and efficacy of treatment should be our primary concerns, convenience is quite important to patients! Phacovitrectomy also offers a significant cost-savings to payers such as Medicare2 and health maintenance organizations, such as Kaiser Permanente.
- In a combined procedure where the cataract surgery is done first, the aforementioned advantages of an intact vitreous are maintained for cataract surgery, yet the advantages of pseudophakia remain for PPV.
MINOR
- If complications occur during cataract surgery requiring vitrectomy (eg, posterior capsular rupture, dislocation of portions of crystalline lens) the retinal surgeon is present to assist. Fortunately, such complications are rare during otherwise routine cataract surgery.
CONS
MAJOR
- As mentioned previously, certain cataract surgery complications may seriously impair achievement of retinal goals.
- Corneal edema often occurs during cataract surgery because of instrumented intrastromal hydration and/or endothelial trauma, especially when cataract extraction with intraocular lens implant (CE/IOL) takes longer than expected. These types of corneal edema cannot usually be corrected by any means in the acute phase and may seriously impair the view to perform retinal surgery. Some of our colleagues who perform phacovitrectomy in the United States routinely approach CE/IOL with a scleral tunnel to decrease associated corneal edema.
MINOR
- Evidence exists that a minority of patients undergoing combined surgery may experience rapid development of posterior capsular opacification, IOL dislocation, increased intraocular pressure, posterior synechiae formation, or the development of anterior chamber fibrin.3
- IOLs fibrose into the capsular bag over time. When this has not yet occurred (ie, during combined cases or within a few weeks of cataract surgery), a higher risk of anterior IOL dislocation or decentration exists. The risk of this is higher when gas or silicone oil tamponade is used.
Cataract Extraction With Intraocular Lens Implant After Pars Plana Vitrectomy
PROS
MAJOR
- If the retinal indication for surgery is urgent (ie, retinal detachment), there is no delay in surgery.
MINOR
- If the retina is detached or if a scleral buckle or long-term silicone oil tamponade is placed during PPV, this approach allows for biometry readings to be performed more accurately. Fortunately, unexpected scleral buckle or long-term silicone oil placement during PPV is rare.
CONS
MAJOR
- The aforementioned advantages of performing PPV in a pseudophakic eye are not available, which may be very valuable in certain cases.
- Performing cataract surgery after PPV is associated with an increased risk of complications (when compared with combined surgery1) and, if one occurs, the retina specialist may not be readily available to assist.
MINOR
- Cataract surgery is associated with a small risk of macular hole reopening (especially if postoperative cystoid macular edema develops) and ERM reformation (secondary to inflammation), but these risks are quite low.
Algorithm for Patients With Significant Cataract and Indication for Pars Plana Vitrectomy
- If the cataract is impairing the view to perform PPV safely in a patient with an emergent indication (ie, fovea-on rhegmatogenous detachment), the patient will either need urgent combined surgery or PPV/pars plana lensectomy (PPL), which is usually performed without concomitant IOL implantation. PPV/PPL may also be considered the primary approach to patients with a dense cataract, urgent indication for PPV and poor visual potential (eg, a rhegmatogenous retinal detachment in a patient with a macular scar).
- If the crystalline lens has significant zonular instability, it is usually unsafe to approach vitrectomy in these patients without concomitant PPL, and the degree of lenticular opacity is not of essential importance to that decision per se.
- If the indication for PPV is nonemergent (ie, macular hole, ERM, certain traction retinal detachments), decide if the cataract is significantly impairing the view to retina enough to compromise the safety of PPV (usually a retinal colleague is needed to weigh-in on this). If so, it can be removed before PPV. As such, one may consider cataract surgery before PPV as a separate or combined surgery.
- If the aforementioned issues do not apply and the retinal indication is not urgent, next decide which problem is more relevant to the patient’s outcome—the cataract or the retinal issue. Usually this is a straightforward assessment, with phakic ERM cases being a notable exception. If the cataract is the primary issue and can be dealt with safely by an anterior segment surgeon, it may be preferable to do this first by itself. If there is an ERM and a significant cataract, it may be beneficial to perform cataract surgery first, as many patients may ultimately end up not needing the ERM peel.
- Is silicone oil planned during PPV for a nonurgent indication (ie, chronic macular hole)? If so, obtaining biometry readings before PPV and SO placement is indicated as the readings will be more accurate. Cataract surgery before PPV may also be preferred.
- If the aforementioned issues do not apply and the retinal indication is not urgent, next decide which problem is more relevant to the patient’s outcome—the cataract or the retinal issue. Usually this is a straightforward assessment, with phakic ERM cases being a notable exception. If the cataract is the primary issue and can be dealt with safely by an anterior segment surgeon, it may be preferable to do this first by itself. If there is an ERM and a significant cataract, it may be beneficial to perform cataract surgery first, as many patients may ultimately end up not needing the ERM peel.
That being said:
- For retinal surgery that is expected to be long in duration, require shaving of the vitreous base and is to highly likely result in the rapid development of a cataract, cataract surgery before or in combination may be preferred. The prototypical cases for this are retinal detachments caused by proliferative diabetic retinopathy or proliferative vitreoretinopathy where the advantages of an improved view and access during PPV are of critical importance and the likelihood of placement of a long-acting tamponade is high, which precipitates cataract. Such retinal cases may often be delayed by 1 to 3 weeks (to permit separate cataract surgery) without negatively affecting the outcome.
- Remember, for cataract surgery performed before/during PPV, the risk of IOL decentration or anterior dislocation may be reduced by placing a suture in the main wound (which may be removed by the retinal surgeon at the conclusion of the PPV). Additionally, try to avoid performing a particularly large capsulorrhexis, and consider placing a 3-piece IOL in the bag, as the haptics are less likely to prolapse into the anterior chamber than a 1-piece IOL.
- A savvy retinal surgeon with a preoperative plan to remove the lens and place an in-the-bag IOL will also be versed in scleral fixation as this allows placement of an IOL even when severe capsular compromise occurs during lens removal. The procedure of securing an Akreos IOL (Bausch + Lomb), in particular, to the sclera with 4-point suture fixation was originally described in China4 and has enjoyed significant popularity among retinal surgeons because of its ease and resultant IOL centration and stability. However, recent concern regarding possible permanent calcifications if the IOL comes in contact with air or gas5 has tempered initial enthusiasm for this approach.
- Lastly, if silicone oil is to be used as tamponade in a combined case (or possibly planned for the future), avoid placing a silicone IOL due to silicone oil droplet adherence.
Acknowledgments
The authors would like to thank Robin A. Vora, MD, medical retina specialist and cataract surgeon, for his assistance in preparing this chapter.
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