Article

Strategies for Combination Vitreoretinal-Cataract Surgery in Pediatric and Adult Patients

Understanding the steps and techniques of combined surgery is critical to success.

Management of vitreoretinal pathology continues to evolve with an increasing trend toward pars plana vitrectomy in combination with phacoemulsification and intraocular lens implantation.1-3 The combination of phacoemulsification with or without IOL and pars plana vitrectomy may have numerous advantages when complex pathology is present. Several authors have described the therapeutic benefits of phacovitrectomy, including decreased macular edema, decreased postsurgical vitreous traction, optimized visualization of the posterior segment, and decreased total number of surgical procedures.1-11 Phacoemulsification following vitrectomy carries increased risks of posterior capsular tears, zonular dialysis, and loss of lens particles posteriorly.12 Combining phacoemulsification with vitrectomy speeds visual rehabilitation and decreases the risks and costs associated with a second surgery. This article focuses on addressing the ongoing challenges and potential benefits of combining vitrectomy surgery with cataract extraction.

ADULT AND PEDIATRIC PATIENT SELECTION CRITERIA

Appropriate patient selection is critical to maximizing visual and anatomic outcomes. Historically, the most common indication for phacovitrectomy surgery is the presence of a visually significant cataract that precludes visualization of vitreoretinal pathology. Patients with preexisting but early lenticular changes who would likely have visual loss due to cataract progression postoperatively are also excellent candidates. Most young patients with clear lenses may not benefit from surgical management of the lens and may be observed following vitrectomy surgery. However, certain pediatric subjects with clear lenses may also benefit from combined phacovitrectomy and lens implantation, especially those with significant comorbidities, such as recurrent retinal detachment, high refractive errors, anisometropia, and unilateral amblyopia. Children who require amblyopia management may benefit from the fast visual recovery and refractive shift.

Victor M. Villegas, MD, is assistant professor of clinical ophthalmology at Bascom Palmer Eye Institute in Miami, FL. Timothy G. Murray, MD, MBA, FACS, is with Murray Ocular Oncology and Retina in Miami, FL. The authors report no related disclosures. Dr. Murray can be reached at tmurray@murraymd.com.

Patients with complex pathology should be individualized. Posterior uveitis patients may benefit from lens extraction and aphakia at the time of primary vitrectomy. In quiet uveitic eyes, IOL placement may be performed. Subjects with retinal detachments and anterior proliferative vitreoretinopathy and/or recurrent retinal detachments may also benefit from phacoemulsification, aphakia, and capsulectomy at the time of primary retinal detachment repair. Also, patients with giant retinal tears may benefit from phacovitrectomy at the time of initial repair to better visualize and manipulate the peripheral retina during surgery. For optimal outcomes, a complete assessment of the pathology should be performed as well as anticipating future steps in management that may involve a second surgery or cataract progression.

PHACOVITRECTOMY PROCEDURE

Successful combination of phacoemulsification with or without IOL implantation and pars plana vitrectomy is dependent on many factors. Understanding the significance of each step and the possible variations in technique is critical to achieve optimal outcomes.

Presurgical Evaluation

Presurgical evaluation should include medical history and evaluation of pupil size after dilation. A history of prior ocular surgery should alert the clinician to the potential for iris sphincter loss, posterior synechia, peripheral anterior synechia, and zonular weakness. Patients with a medical history of benign prostate hyperplasia who have used α1-adrenergic receptor antagonists such as tamsulosin are at risk for intraoperative floppy iris syndrome.13-16 The reported incidence of floppy iris syndrome associated with tamsulosin ranges from 43% to 100%.13,15

Small pupil size may decrease the work field and increase the rate of complications, such as iris trauma, anterior capsular tears, posterior capsule rupture, and vitreous loss.17 Other drugs, such as saw palmetto, finasteride, antipsychotic agents, angiotensin antagonists, and β-blockers, have also been associated with floppy iris syndrome. Recognizing patients at risk for complications due to anterior segment pathology, including poor dilation, allows the surgeon to better counsel patients about risks associated with the individual surgery.

In most cases, both a cycloplegic (eg, tropicamide 0.5%) and sympathomimetic (eg, phenylephrine 2.5%) are used. Avoidance of long-acting cycloplegic drops may decrease the incidence of posterior synechiae.18 We routinely use 10% phenylephrine to maximize the visualization of the posterior segment during vitrectomy.

In cases where poor pupil dilation is expected, additional tools in the operating room can minimize the surgical complexity. Intracameral epinephrine injection may help maintain adequate pupil size during the procedure. The technique involves injecting epinephrine into the anterior chamber prior to viscoelastic placement. Cohesive viscoelastic agents may also aid in mechanically enlarging the pupil. Iris hooks and Malyugin rings more definitively manage intraoperative small pupils. These surgical devices are most important when managing cases of posterior synechiae and other iris membranes (eg, neovascular glaucoma, tumors, and iridocorneal endothelial syndrome). Patients with complex medical history and/or pathology may benefit from having multiple tools readily available in the operating room.

Vitrectomy Systems

Transconjuctival, sutureless trocar vitrectomy systems (23 g, 25 g, and 27 g) have progressed significantly during the past decade. Advantages of the smaller-gauge systems include improved safety of fewer iatrogenic breaks, less patient discomfort, less astigmatism, and enhanced visual rehabilitation. These risks may decrease with decreasing gauge. However, in patients with intraocular foreign bodies and in surgeries requiring the use of a fragmatome, a single 20-g sclerotomy may still be required.

Modern systems operate with faster cutting rates and smaller volumes per cut to allow the surgeon to minimize traction during surgery. This becomes particularly important while close shaving in cases of retinal detachment. Faster cutter rates may also decrease intraoperative iatrogenic tears and retinal hemorrhage due to traction.

The introduction of valved trocars has improved the fluidics of combined phacovitrectomy by preventing fluid reflux through an open cannula. Difficulty introducing instruments, such as the soft-tipped extrusion cannula, through the valved cannula may be experienced. However, this may be managed by using the push-pull technique or displacement of the valved leaflets. Another technique to avoid the difficulty of introducing flexible-tip instruments is using a larger-gauge valved cannula system than the instrument to be utilized. The stabilization of the fluid dynamics during surgery outweighs any difficulties, especially in complex, previously vitrectomized eyes.

We typically place the trocars at the beginning of surgery due to better globe stability. Alternatively, in Europe, patients undergo complete phacoemulsification with IOL placement prior to placement of the trocars. The infusion cannula may be placed but kept off until the phacoemulsification portion of the procedure is completed to decrease posterior pressure during cataract extraction.

Early trocar placement permits the surgeon to perform a limited core vitrectomy in situations in which increased posterior pressure makes the anterior chamber uncomfortably shallow for safe lens manipulation. Decompression of the posterior segment to relieve posterior pressure is particularly important in pediatric patients and in nanophthalmic eyes. In cases of a posterior capsule tear, it allows for rapid access to the posterior segment for added flexibility during surgery.

Incisions

Conjunctival displacement during sclerotomy construction maximizes the conjunctiva and scleral wound distance. The displacement of the conjunctiva is important for the transconjunctival sutureless technique to decrease the risk of a vitreous wick in the incision site as well as to minimize access of the tear film into the sclerotomy. Performing an oblique trocar wound construction provides added incision stability and reduces postoperative hypotony and air/gas leaks after retinal detachment surgery.

Sclerotomy location is also important and should be individualized to each patient. Sclerotomies should avoid conjuctival scars, filtering blebs, ocular tumors, implants, and prior grafts. The placement should optimize the angle for intraocular access and comfort. In naive eyes, trocars should be placed near the horizontal meridian to reduce the risk of touching the eyelids when manipulating the globe to visualize the inferior and superior retina.

Corneal incisions should be placed to optimize the surgical approach of the lens while considering existing trocar placement. Choosing the location of the corneal incisions at the steep axis of corneal astigmatism improves postoperative astigmatic correction. Biplanar clear corneal incision is preferred due to corneal wound stability. Closure of the main wound with 10-0 Nylon sutures prior to the pars plana vitrectomy minimizes the possibility of iris prolapse during vitrectomy and postoperatively. In pediatric patients, we prefer suturing the cornea with Vicryl sutures (Ethicon) to minimize postsurgical would manipulation.

Capsulorhexis

A continuous curvilinear capsulorhexis is a critical step during phacovitrectomy surgery. In contrast to a “can opener” approach, this technique creates a stable opening in the anterior capsule and allows access to the nucleus. In adults, we perform a capsulorhexis of approximately 6.5 mm in diameter to maximize the view postoperatively in patients at risk for developing significant posterior capsule opacification. The larger capsulorhexis also allows for easier manipulation of the nucleus during phacoemulsification and chopping. However, a smaller capsulorhexis may be preferred, especially in cases of premium IOLs or if a sulcus lens is planned.

In pediatric patients, we perform a smaller capsulorhexis of approximately 4.5 mm in diameter because extensive nuclear manipulation is not performed. It also allows for better lens stability both in the sulcus and in the capsular bag.

Patients with complex cataracts, including anterior capsule fibrosis, anterior polar cataracts, and white cataracts, should undergo preoperative examination with ultrasound biomicroscopy. Sonography allows evaluation of the ciliary body, zonular complex, and iris diaphragm to identify uveal tumors, zonular dehiscence, and anatomical variants prior to surgery. Staining the anterior capsule in complex cases improves visibility and anatomical landmarks. If a continuous curvilinear capsulorhexis cannot be completed due to anterior capsule fibrosis, the vitrector or intraocular scissors can be used to perform the capsulorhexis.

Femtosecond laser–assisted capsulorhexis has been performed in cases of combined phacovitrectomy.19-21 Significant controversies continue to exist regarding the use of the femtosecond laser to assist in cataract surgery since numerous reports of posterior capsule tears and other complications have been published.22 However, case series of femtosecond laser-assisted phacovitrectomy are limited and long-term follow-up unavailable.

Lens and Cataract Extraction

Phacoemulsification may be performed before vitrectomy to optimize the view of the posterior segment during subsequent vitrectomy. However, in cases where an adequate view is present, cataract extraction may be performed following the vitrectomy. In cases of vitreous hemorrhage, clearing the hemorrhage from the posterior segment to elicit a red reflex may be beneficial.

Phacoemulsification should be performed at the iris plane whenever possible to minimize both corneal edema and posterior capsular breaks. We prefer to use a quick chop technique to minimize ultrasonic energy. However, phacoemulsification techniques vary widely depending on surgeon experience and pathology. Recent reports have successfully reported on phacofragmentation with femtosecond lasers.19-21 However, economic and long-term safety concerns continue to prevent most large medical facilities from performing this technique.

Pediatric patients do not need to undergo phacoemulsification of the nucleus because the lens material is mostly soft. However, the lens in pediatric patients is thinner, and inadvertent rupture of the posterior capsule is possible with minimal manipulation. We routinely use the vitrector in aspiration mode to remove the lens nucleus and the cortical material. When using the vitrector in the anterior chamber, it is important to place the infusion into the anterior chamber via a paracentesis to minimize anterior chamber collapse. Other variations in technique include using the irrigation-aspiration handpiece, Simcoe cannula, or phacoemulsification handpiece in aspiration mode.

Intraocular Lenses

IOL implantation at the time of primary combined cataract extraction and vitrectomy depends on many factors. Pediatric patients younger than 1 year of age may not be good candidates for IOL implantation because of unreliable refractive outcomes and inadequate anterior segment space. Patients with anterior proliferative vitreoretinopathy, endophthalmitis, retinal detachment associated with retinopathy of prematurity, and uveitis may benefit from aphakia and secondary lens implantation.

The IOL can be implanted after cataract extraction or after vitrectomy completion. The lens should be placed in the capsular bag unless there is any concern of a posterior capsule rupture. Sulcus lens placement is recommended every time a posterior capsule break is seen or suspected. To minimize IOL pupillary capture and IOL subluxation or decentration during vitrectomy or postoperatively, we routinely place viscoelastic into the anterior segment and bag prior to IOL placement. After placement, we do not remove the viscoelastic material from the anterior segment, and we suture the main corneal wound. This minimizes flow through the anterior segment during vitrectomy and possible IOL movement. Although some patients may experience a transient IOP increase due to the presence of the viscoelastic agent, almost all patients have a normal IOP pressure 48 hours after surgery. In cases of aphakia and silicone oil tamponade, we also place viscoelastic material into the anterior chamber to minimize the possibility of anterior chamber silicone oil migration early in the postoperative period.

Silicone IOLs should be avoided in all cases of combined cataract and vitrectomy surgery. Silicone oil beads and condenses on the surface of the IOL when intraocular silicone oil is present. Additionally, during fluid-air exchange, tiny droplets of fluid coat the exposed posterior surface of the silicone IOL and impair the surgeon’s view. Because of their physical properties, acrylic IOLs are the preferred choice for most vitreoretinal surgeons.

A recent study investigated whether complication rates are comparable in patients undergoing phacovitrectomy using multipiece IOLs vs single-piece foldable IOLs.23 The study included 184 subjects who underwent phacovitrectomy in a single-center, multisurgeon study. There was no difference in the total incidence of postoperative complications between combined surgery using single-piece and multipiece intraocular lenses (P=.80) or among individual complications between the 2 groups, including synechiae (2.7% vs 5.3%; P=.61), pupillary capture (0.7%% vs 2.6%; P=.36), and lens subluxation (1.4% vs 0%; P>.99).

Studies have also reported the outcomes of combined cataract surgery with toric IOL implantation when performed in conjunction with transconjunctival sutureless pars plana vitrectomy.24-25 Results of these studies suggest that toric lens position and axis remained stable after implantation during combined cataract and small-gauge vitrectomy surgery.

Currently, we prefer to use a 3-piece IOL due to dual stability in the sulcus and the capsular bag. However, the choice of IOL varies depending on surgeon expertise and IOL availability. No significant studies to date have evaluated the outcomes of multifocal or accommodative IOL implants in patients undergoing combined cataract extraction and vitrectomy surgery.

Primary Posterior Capsulectomy

Visually significant opacification of the posterior capsule is the most common postsurgical event after phacovitrectomy.18 In many patients with combined surgery for macular hole or diabetic retinopathy, significant posterior capsular opacification occurs within the first 2 months.26 Other postoperative findings of combined surgery may include increased IOP, corneal epithelial defects, corneal edema, vitreous hemorrhage, and retinal detachment.

Recent studies have reported that a primary posterior capsulotomy with or without posterior optic buttonholing in phacovitrectomy can successfully achieve IOL stability during and after surgery.27-28 This technique may also prevent posterior synechiae and posterior capsule opacification formation after phacovitrectomy.

In pediatric patients, due to a high incidence of posterior capsule opacification, it is important to perform a small central posterior capsulectomy in children who may not cooperate for YAG capsulotomy after surgery. In adults, a small capsulectomy may also be performed to avoid the need for a second procedure and to ensure complete separation of Wieger’s ligament.

Vitrectomy as Part of Combined Surgery

Both instrumentation and technique for pars plana vitrectomy continue to evolve. Significant benefits exist in select adult and pediatric patients who may already have early cataracts, in whom progression to a visually significant cataract is expected after vitrectomy, or in those who need cataract extraction for better intraocular management of posterior segment pathology.

Several studies have shown that combined phacovitrectomy has a similar risk profile as compared with vitrectomy alone in patients undergoing small-gauge surgery.29-30 The complications and difficulties related to phacoemulsification surgery following vitrectomy are avoided by performing combined surgery. This approach also allows a more extensive peripheral vitrectomy while minimizing iatrogenic damage to the crystalline lens. Further evolution of this technique may lead to better visual outcomes in patients with complex vitreoretinal conditions.

CONCLUSION

Phacovitrectomy at our institution has had an outstanding success rate. More than 95% of our patients have 2-line improvement 6 weeks after surgery. We have had no cases of hypotony, endophthalmitis, or lens displacement. The retinal detachment rate is 5% in patients with high-risk characteristics for retinal detachment. RP

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