Expert perspectives on the evolution of retina practice, procedures, technologies and instrumentation.
Rajeev H. Muni, MD, MSC, FRCSC, FASRS
Describing the history of a procedure can be challenging, as the published literature alone often does not paint the full picture. This history of pneumatic retinopexy (PnR) is based not only on what has been published, but from discussions with some of the giants in retina.
In 1911, Ohm published cases where he injected air into the vitreous cavity in an attempt to reattach the retina, with variable success.[1] At that point there was no awareness of the causative role of the retinal break.[2,3] Subsequently, Jules Gonin famously determined that the causative retinal break must be treated and closed to allow the retina to reattach.[4–6] This was an important turning point in retinal detachment repair, as it led to a series of innovations that improved primary reattachment rates over the decades.
Arruga later injected air into the vitreous cavity as a “vitreous expander” in combination with diathermy and external drainage to treat retinal detachment.[7,8] However, it was Rosengren who introduced the concept of “tamponade” of the retinal break in 1938 when he published an article about injecting air into the vitreous cavity in combination with external drainage and diathermy with reasonable reattachment rates.[9]
Custodis in 1949 was the first to perform scleral buckling; he taught us that a retinal detachment could be repaired without drainage of subretinal fluid (SRF) by closing the break and allowing the retinal pigment epithelium pump to reabsorb the SRF.[10] This was an important concept, that Paul Tornambe once said, “is largely ignored by modern-day vitreoretinal surgeons”. Gonin and Custodis thus laid an important foundation for PnR to be developed; and Ohm, Arruga, and Rosengren were key in introducing the use of air in retinal detachment repair. This was followed by decades of fierce debates about drainage vs non-drainage scleral buckle (SB) surgery.
As the scleral buckle era was in full force, several individuals were important in introducing the use of intraocular gas in ophthalmology. Edward Norton published a paper [11] in 1969 on using intravitreal air and SRF drainage to manage giant retinal tears. In 1973, he published another paper [12] on intravitreal gas with drainage for select retinal detachments. Norton introduced sulfur hexafluoride[11,12] to vitreoretinal surgery and Harvey Lincoff introduced the perfluorocarbon gases.[13,14]
Ingrid Kreissig published a paper [15] in 1979 in which she described a treatment for complex retinal detachments where multiple expansile bubbles were injected without SRF drainage in cases not amenable to scleral buckle. She presented this data at a Club Jules Gonin meeting in the early 1980s, where Alfredo Dominguez was in the audience. (Figure 1)
On the North American side, Edwin Boldrey presented at the 1981 Paul Cibis Club Meeting on bedside injection of air to salvage a failing scleral buckle.[16] Robert Machemer famously said after Boldrey’s presentation, “The retina wants to heal itself and if you don’t do too much to it, it probably will.” It was at this same meeting where Paul Tornambe later said he and George Hilton’s “lightbulbs” went off regarding the possibility of PnR. Shortly after this, George Hilton presented 7 PnR cases at the West Coast Retina Study Club. Paul Tornambe and Neil Kelly had also commented at that meeting that they had tried a few.
In 1985, Dominguez published the first paper [17] in the Spanish literature on what he referred to as pneumocausis—an outpatient procedure for repairing routine retinal detachment with cryopexy and intraocular gas injection (Figure 2). A year after Dominguez’s paper in the Spanish literature, George Hilton presented on “pneumatic retinopexy” at the American Academy of Ophthalmology (AAO) Annual Meeting (Figure 3). Hilton and Grizzard subsequently published an initial paper on PnR with 90% primary reattachment rate in 1986.[18]
According to a book [19] by Dominguez (Figure 4), he was surprised that Hilton was slated to present about PnR at the 1986 AAO meeting (Figure 5)—and the day before the presentation, Dominguez approached Hilton and gave him a copy of his Spanish paper that had been published the prior year.
In Dominguez’s book, he wrote about how he was very upset that when Hilton presented the data, he did not acknowledge Dominguez’s prior publication, nor did Hilton reference it in the subsequent publication in Ophthalmology; rather, he listed it in an appendix, which Dominguez felt was not appropriate. This issue led to years of behind-the-scenes controversy, with Dominguez writing multiple letters to the editor-in-chief of Ophthalmology attempting to set the record straight with a manuscript he wrote. However, his paper was rejected by the journal. Dominguez spent many years in bitterness over this, leading him to write his book detailing the entire ordeal.
Dominguez stated in that book that he was unaware of Kreissig’s 1979 paper when he started thinking about injecting gas for managing routine retinal detachments. Rather, he mentioned learning Landers’ fluid-gas exchange technique in-office to repair some retinal detachments that occurred after vitrectomy. Dominguez credited this experience as instrumental in his progress toward “pneumocausis”.
Although Dominguez did concede that Kreissig had the first paper on gas injection without drainage, he also stated that this was for complex detachments and that Kreissig and Lincoff were not in support of a “gas” technique for routine retinal detachments. Around 1984, Dominguez started performing “pneumocausis” as an in-office procedure with laser or cryopexy to treat routine retinal detachments.
Much evidence suggests that Kreissig may have inspired several surgeons to use expansile gas without drainage for retinal detachment repair. However, it appears that Dominguez was the first to perform in-office primary retinal detachment repair for routine cases with what is now known as PnR. Hilton started performing PnR around the same time after Edwin Boldrey’s presentation. Based on the published literature, priority goes to Dominguez for introducing PnR as an in-office procedure for routine retinal detachments.
Hilton initiated the multicenter Pneumatic Retinopexy Trial; however, Tornambe deserves a lot of credit for carrying it out and coordinating this first randomized controlled trial in rhegmatogenous retinal detachment repair, as Hilton left the United States on a mission.[20] The Pneumatic Retinopexy Trial demonstrated no statistically significant increase in primary failure with PnR vs scleral buckle and that fovea-off cases had superior final visual acuity with PnR vs SB (Figure 4).
Tornambe mentioned to me that there was always fierce opposition to PnR; he said it would be an uphill battle to convince people to adopt PnR despite the superior functional outcomes. Paul Tornambe was a big supporter of PnR right up to his last days. He participated in our instructional course at the AAO meeting virtually or by pre-recorded talks in 2019 as he was not able to travel in his final years.
In 2018 and 2019, the PIVOT trial [21] results were published. This randomized trial compared PnR to vitrectomy, the most popular method of treating retinal detachment over the preceding 2 decades. The popularity of PPV for retinal detachment rose in large part due to tremendous advances in vitrectomy platforms and surgical instrumentation.
However, there was never a randomized trial that showed a functional outcomes benefit of vitrectomy over other surgical procedures. The PIVOT trial tried to address this gap in the literature. The results showed superior visual acuity and vertical metamorphopsia outcomes for PnR compared to PPV despite the 12% lower primary reattachment rate and similar secondary reattachment rate with PnR (Figure 6).
The PIVOT trial[21] and the subsequent imaging work in retinal detachment repair allowed us to understand several important concepts that led to suboptimal outcomes as a result of anatomic abnormalities such as retinal displacement,[22–25] outer retinal folds, and outer retinal band discontinuity.[26–28] These anatomic abnormalities tend to be worse with procedures such as vitrectomy, where large gas tamponades are used and the retina is often forcefully and rapidly attached with internal drainage. Thus, the more recent interest in PnR stems from an interest in reducing the risk of unwanted anatomic abnormalities and improving functional outcomes for patients.
Understanding these novel concepts has led to a recent rethinking how we do other procedures such as vitrectomy and scleral buckle. The historical emphasis of focusing only on primary reattachment rate is now evolving among today’s vitreoretinal surgeons into considering a variety of outcomes, including integrity of retinal reattachment and functional outcomes for patients.
This is a great example of how a specific surgical technique has taught us so much about the disease and about the principles that ideally should be followed to repair routine cases. The foundation of closing the retinal break and not requiring drainage first introduced by Gonin and Custodis respectively remain important fundamental principles.
The principles we have been taught from the exploration of PnR with imaging, specifically that large gas bubbles and rapid internal drainage may not be ideal, will certainly lay the foundation for new and improved techniques of treating rhegmatogenous retinal detachment with better functional outcomes for patients in the near future.
Paul Tornambe prepared a narrated video, “The Evolution of RD Surgery Over the Last 40 Years,” for our PnR course at the 2019 AAO meeting, just prior to his passing.
Acknowledgements: Dr. Muni acknowledges Dr. Reut Shor for assisting with references and Dr. Alvaro Fernandez-Vega for assisting with research around the introduction of PnR in the literature. Images courtesy Rajeev Muni, MD.
References
(Milestone essay published 2024)
Additional Resources