Historically, 360-degree laser retinopexy straddling the posterior vitreous base (360 LR) during pars plana vitrectomy (with or without scleral buckle) for primary repair of rhegmatogenous retinal detachment (RRD) (Figure 1) has been advocated by some in cases where no retinal break can be identified¹ or for detachments associated with giant retinal tears.² Surgical success when 360 LR has been employed has led to the use of this practice for routine retinal detachment cases also, in the hopes of improving surgical outcomes. Potential issues could include induction of inflammation, epiretinal membrane formation, and iatrogenic tonic pupil (from laser injury to the long posterior ciliary nerves).

However, until recently, critical evaluation for scientific evidence that this practice is effective has not been undertaken. Two relatively small retrospective studies have examined the use of intraoperative 360 LR during primary vitrectomy for RRD and have yielded conflicting results;^3,4 one relatively small prospective study has shown no benefit.⁵

A large, multicenter, retrospective study (PRO Study report number 4) was recently undertaken to evaluate the effectiveness of 360 LR in simple-to-moderately complex RRD: patients in the 360 LR group had significantly lower anatomical success and worse final visual acuity compared to control eyes that did not undergo 360 LR.⁶ The authors suggested that this outcome may have occurred due to induction of iatrogenic retinal breaks (at the posterior edge of the laser) and/or more significant proliferative vitreoretinopathy (PVR) in the failed cases. They proposed that laser spots placed more posteriorly during 360 LR may have indicated the need for larger retinectomies in subsequent surgeries that may have promoted secondary epiretinal membranes, which in turn could result in poorer final visual acuity.

The PRO Study found that surgeon preference was a significant factor in the application of 360 LR: institution and more years after completion of training were found to be influencing factors in the use of 360 LR. Twenty-one percent of surgeons used 360 LR in the majority of their cases. Therefore, a large group of surgeons currently use 360 LR.

Here we will discuss the merits and potential disadvantages of 360 LR and whether, or when, it should be considered. We are fortunate to have the commentary of Jayanth Sridhar, MD, and Edwin Ryan, MD.

When and How to Use 360 Laser Retinopexy

Jay Sridhar, MD

One of the fascinating aspects of being a retinal surgeon is the diversity of approaches to relatively common procedures, such as RRD repair. Given the limitations of even well performed surgical studies, there is wide variability in practice patterns as surgeons develop individual preferences based on a mixture of literature review, anecdotal experience, and risk tolerance. Whether to perform 360 LR routinely during pars plana vitrectomy for RRD is a classic example of a vitreoretinal conundrum.

The ultimate goal of routine 360 LR during vitrectomy is to reduce the risk of retinal detachment by barricading retinal breaks that were not identified intraoperatively. A handful of small retrospective studies have suggested benefits to 360 LR in different scenarios. Dirani et al reported a retrospective single-institution cohort study comparing patients receiving LR only to identified pathology vs 360 in the setting of RRD treated with vitrectomy and gas tamponade.⁷ They reported a 75% reduction in the odds of retinal redetachment without any difference between groups in epiretinal membrane formation. Similarly, Koh et al found that 360 laser during vitrectomy for vitreal and macular indications also reduced risk of postoperative detachment by 74%.⁸ The use of 360 LR may also be beneficial in eyes with history of retinal detachment undergoing silicone removal.⁹

No prophylactic treatment is without potential drawbacks, however. More laser equals potentially more inflammation, epiretinal membrane formation, and pupil issues due to damage to the long ciliary nerves. Also, excessive burn power may result in retinal atrophy and iatrogenic retinal breaks. Finally, in the case of subsequent proliferative vitreoretinopathy and redetachment, prior chorioretinal scarring from laser may interfere with maneuvers to increase retinal mobility and promote retinal reattachment, such as a relaxing retinectomy.

The PRO Study report number 4 offers the largest retrospective series examining the impact of 360 LR on retinal detachment repair outcomes.⁶ The authors reported that while 360 LR did not seem to result in statistically significant epiretinal membrane formation or cystoid macular edema development, it also did not improve final reattachment rates significantly. In addition, once case complexity was adjusted for, 360 LR was associated with higher risk of redetachment and worse final visual acuity.

How then should the vitreoretinal surgeon approach the decision to perform 360 LR during vitrectomy for RRD? In the author’s opinion, the evidence is not sufficient to suggest routine use in every retinal detachment case, and in fact may be overkill in those cases with localized pathology or a single retinal break. A meticulous peripheral scleral depressed examination should be undertaken in all vitrectomies, regardless of indication, and is especially important for RRD cases. An experienced surgeon with an adequate peripheral view should feel confident in relying on a depressed examination to guide peripheral laser treatment. Also, if a well placed scleral buckle supporting the vitreous base and peripheral pathology is placed at the time of vitrectomy, that should tip the scales away from routine 360 LR, as the buckle should achieve the same purported benefits of reducing risk of peripheral breaks and future redetachment.

In what cases should 360 LR be considered? The PRO study, among other studies, have suggested that redetachment rates are higher in phakic patients undergoing primary vitrectomy than in phakic patients undergoing scleral buckle or scleral buckle vitrectomy.^6,10 For this reason, the author prefers avoiding primary vitrectomy in most phakic patients with RRD; however, in the instance that one does elect to perform primary vitrectomy in a phakic patient, perhaps a lower threshold should exist for 360 peripheral laser to try and reduce this known higher rate of redetachment. Some eyes, especially pseudophakic ones with capsular phimosis or a multifocal intraocular lens, may not allow for as optimal a peripheral view during intraoperative scleral depressed examination, and as such, 360 LR may be beneficial to barricade potentially missed small retinal breaks (on the other hand, adding a scleral buckle instead may also offer a similar benefit). Finally, for the eye with multiple retinal breaks (greater than 7) across all 4 quadrants, it may be reasonable for the surgeon to “connect the dots” and fill in small gap areas between lasered breaks as part of 360 laser retinopexy along the vitreous base.

One final point: how 360 laser retinopexy is performed is almost as important as the decision to perform it. If possible, try to identify and avoid the ciliary nerves to reduce risk of postoperative neurotrophic cornea and mydriasis. Avoid placing random scattered posterior rings of laser and concentrate on meticulous laser with scleral depression from the vitreous base out to the ora serrata. Finally, avoid overcooking the retina with small white-hot burns that may atrophy and focus on larger greyish-white laser marks that are semi-confluent; using a continuous or long-duration endolaser with lower power may help titration of these applications.

Data That Inform a Decision to Perform 360 Laser Retinopexy

Edwin Ryan, MD

Routine application of 360 LR during PPV or PPV with scleral buckling (PPVSB) for primary RRD is advocated by some. The rationale is that this may treat unseen breaks or act as prophylaxis against future breaks. However, there are theoretical risks that unnecessary or excessive laser may induce inflammation and lead to complications such as PVR¹¹ or, in the case of redetachment, lead to multiple small breaks from the area of laser scarring.

There have been relatively few papers looking at this clinical question, and findings are conflicting. Most are small, single-site retrospective series. A recent paper compared 2 cohorts that underwent 23-gauge primary PPV for RRD repair.⁷ One group (n=86) was treated with laser retinopexy around tears/holes/lattice, and the other (n=65) received 360 LR. Redetachment was significantly less common in the group treated with 360° LR. Another retrospective study reviewed cases with undetected breaks and found 360 LR to be more effective than targeted laser in this uncommon setting.⁴ Bilgin et al, in a prospective randomized trial, divided 50 patients into 2 groups, one receiving 360 LR and the other laser to the breaks alone.⁵ They found no statistical difference in anatomic or functional outcomes.

The PRO Study, which I organized and ran, was a large multicenter retrospective cohort study of primary RRD.¹² Five centers were involved, including 61 surgeons and more than 2,700 cases, with the intent of creating a very detailed database from which cohort studies could be performed.

To date, 15 have been published. Documentation of 250+ data points including use of 360 LR was performed on each case. Wang et al reviewed the 2,240 cases that underwent PPV or PPVSB regarding use of 360 LR and found that its use was associated with worse final anatomic and visual outcomes.⁶ He found that 360 LR was used in 23% of cases, but 21% of the surgeons used it in most of their cases. Multivariate analysis indicated that surgeon preference was the main driver of its use. A subsequent analysis of the PRO database examining surgeons with high vs low single-surgery success (>90% single surgery success vs <80%) found a higher usage of 360 LR (29% of cases vs 14%) in the low-success group.¹³

My approach to primary PPV and PPVSB is supported by these PRO substudy findings. I treat breaks and lattice and do not routinely do 360 LR. Two exceptions to this rule are total detachments, because I treat the areas where the retina was detached with endolaser, and giant tears. Another consideration that has not been examined because it is difficult to quantify is the intensity of laser application. The heavier the laser, the greater the risk of inflammation, fibrin formation, and risk for PVR. My endpoint is a gray laser take, not a chalk white one. Every case is different, and the treatment plan needs to be individualized, but it appears that the routine application of 360 LR is not beneficial and may be detrimental. RP

REFERENCES

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