Surgical Options for the Back of the Eye

Recent innovations are changing the way eye care specialists manage vitreomacular pathologies.

By W. LLOYD CLARK, MD

There have been many advances in medical therapy for retinal diseases such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion. What surgical improvements are taking place?

Like the field of medical retina, the landscape of vitreoretinal surgery continues to evolve. Microincisional vitrectomy surgery, for example, has several advantages for physicians and patients. In many cases, procedures can be performed more efficiently and with less associated morbidity than conventional 20-gauge surgery. This article explores recent reports regarding small-incision surgery for the repair of retinal detachment (RD) and examines whether outcomes with modern techniques are comparable to those achieved with traditional ones. Included in the discussion will be intraoperative optical coherence tomography (OCT), an emerging technique designed to improve outcomes in epiretinal proliferations. The use of microplasmin (Ocriplasmin; ThromboGenics, Inc.) in the treatment of symptomatic vitreomacular adhesions (sVMAs) and macular holes will also be reviewed.

PRIMARY VITRECTOMY

Each year, the American Society of Retinal Specialists polls its membership about current treatment trends. Between 2006 and 2011, these polls indicate that primary vitrectomy became a more common procedure for the repair of rhegmatogenous RD. In 2006, 40.6% of respondents reported that their preferred technique for managing a pseudophakic, macula-on RD was pneumatic retinopexy, 26.7% reported primary pars plana vitrectomy (PPV) as their preferred strategy, 12.5% said PPV with a scleral buckle, and 20.3% chose a primary buckle.1 According to data compiled for 2011, the most popular procedure in this clinical setting was PPV (47.7%), followed by PPV with a scleral buckle (22.2%), pneumatic retinopexy (19.9%), and scleral buckle alone (10.3%).1 An increased use of primary vitrectomy was also reported in the repair of phakic detachment.1

Based on a recently reported case series, surgeons’ increased use of PPV may be associated with more positive outcomes. At the 2011 meeting of the American Society of Retinal Specialists, Robert Avery, MD, reported a retrospective review of 793 eyes with primary RD.2 Redetachment was highest in the pneumatic retinopexy group (31.9%), followed by relatively low rates among patients undergoing scleral buckle (9.9%), PPV (3.1%), and PPV with a scleral buckle (2.4%).

At the 2011 Annual Meeting of The Retina Society, two separate series demonstrated the effectiveness of primary vitrectomy for primary, uncomplicated RD. Mark Johnson, MD, reported primary anatomic success in 95.7% of eyes and final anatomic success in all but one of 93 reviewed.3 Final BCVA was at least 20/40 in 77% of eyes and 20/200 or better in 89%. Homayoun Tabandeh, MD, reported on a series of 156 consecutive eyes that underwent repair of primary RD with microincisional vitrectomy.4 He found that primary anatomic success was achieved in 94% of eyes. Visual outcomes were also excellent, with a BCVA of better than 20/40 in 44% of eyes, 20/50 to 20/100 in 24%, and 20/200 or worse in 32%. These data support the increased use of microincisional vitrectomy for the repair of primary RD.

OTHER INNOVATIONS

Microincisional vitrectomy is often ideal for the management of vitreomacular interface abnormalities (eg, macular hole, vitreomacular traction, epiretinal membrane), because it requires minimal ocular manipulation. Recent clinical trials suggest that some of these cases may be managed successfully without surgical intervention. Microplasmin, a recombinant protein shown to cleave at the vitreoretinal interface, is currently in the late stages of clinical development.

Also at The Retina Society’s Annual Meeting, Peter Kaiser, MD, presented findings from the MIVI-TRUST (Microplasmin for Intravitreous Injection-Traction Release Without Surgical Treatment) phase 3 clinical trial evaluating microplasmin in the nonsurgical management of sVMAs and macular holes.5 In the study, 464 of 652 eyes received 125 μg of the active drug, and the remainder received a placebo intravitreal injection of saline. Twice as many eyes (26.9% vs 13.3%) that received microplasmin experienced resolution of their sVMAs. In eyes with macular holes, 40.6% achieved closure with a single injection. Based on these encouraging results, the FDA is currently reviewing microplasmin for the treatment of sVMAs and macular holes.

INTRAOPERATIVE OCT

Finally, in a development that brings the clinic to the OR, intraoperative OCT is becoming technically feasible for select centers around the world. With the availability of handheld acquisition devices and portable, computer-based processors, OCT can be brought into the operating suite to examine patients with a wide array of pathology.

Sunil Srivastava, MD, reported on his experience with such a device at the American Society of Retinal Specialists Meeting.6 He presented video examples of patients undergoing surgery for macular hole and proliferative diabetic retinopathy. In both, the major benefit of intraoperative imaging appeared to be the ability to identify epimacular proliferations that were unrecognizable clinically. In another example, the decision to halt dissection was made based on the ability to identify any further membranes. As availability increases, OCT technology will undoubtedly give surgeons information that is critical in making decisions in the OR.

The drawbacks of handheld devices include difficulties in obtaining reliable scans due to movement of the handpiece and the inability of the patient to fixate under sedation as well as the potential for contamination of the surgical field. Several microscope-mounted prototypes are in development, which in the long run may represent a better alternative to portable devices.

Reimbursement, or the lack thereof, may be a limiting factor in the adoption of this technology. Just as the OCT device has revolutionized the medical management of macular disorders, however, intraoperative OCT has the potential to add significant value to the surgical management of retinal disorders.

CONCLUSION

Improvements in surgical results for vitreoretinal disorders have been incremental as technology and techniques have evolved. Recently, the adoption of microincisional vitrectomy surgery has further improved ophthalmologists ability to manage surgical cases. Medical adjuncts such as microplasmin and the integration of OCT into the OR are examples of the next phase of surgical advancement. The convergence of what were once exclusively medical or surgical techniques into integrated therapy will improve outcomes for patients with retinal diseases.

W. Lloyd Clark, MD, is in private practice at Palmetto Retina Center, LLC, in Columbia, South Carolina. He acknowledged no financial interest in the product or company mentioned herein. Dr. Clark may be reached at (803) 931-0077; lclark@palmettoretina.com.