Do you ever look at a patient’s chart and your eyes cross from all the surgical abbreviations? It looks something like this: s/p PPV/FAx/EL/SO. s/p cryo/PR. s/p PPV/PFO/MP/FAx/C3F8. s/p SB/LPexy.
As optometrists, we aren’t going to be performing these surgeries, but we are going to be comanaging patients who’ve had these surgeries – sometimes in the immediate postop period and sometimes later on. And like I always say, if you want to be called an eye doctor, you have to know everything about the eye. This includes surgeries. So let’s break down this alphabet soup of retinal surgeries, specifically focusing on vitrectomies.
First things first: s/p. Most of us know this stands for status-post, but what does that even mean? Well, like most Latin phrases, you translate it to English backwards: Post-state. Which is quite descriptive of a patient after surgery, isn’t it? Any surgery big or small forever alters a person’s body, and the state of their body (or eye) can be described as before/after (pre/post) that surgical alteration.
PPV: Pars plana vitrectomy (as opposed to anterior vitrectomy). An anterior vitrectomy is typically done during cataract surgery if a posterior capsule is torn and some lens fragments fall into the anterior vitreous. A PPV is a planned surgery to remove the entire vitreous (except the vitreous base), and the surgeon makes the incisions (called sclerotomies) through the pars plana, to avoid piercing the retina. This is typically done 3.5 mm from the limbus, and there are typically three sclerotomies, so observe these areas of the sclera at post-op visits.
FAx: Fluid-air exchange. A PPV is more complicated than just sucking out the vitreous. Whatever volume of material is removed from the vitreous chamber must be equally and immediately replaced, lest the eye lose pressure and suffer choroidal detachment or suprachoroidal hemorrhage. While the vitrector is cutting and removing vitreous, there is an infusion cannula bringing balanced salt solution (BSS) into the vitreous chamber. So after the vitreous is completely removed, the vitreous chamber is filled with a saline-like fluid. But in cases of retinal break/detachment, more treatment is needed than simply removing the vitreous. The fluid is exchanged for air, in a process known as FAx. Remember that whatever is listed last (fluid-air exchange, air-fluid exchange, air-gas exchange, etc.) is what remains after the procedure. So in cases of retinal detachments, the BSS fluid is removed and replaced with air to help push out subretinal fluid. After that, it’s common to do an air-gas or air-oil exchange to give a stronger tamponade to keep the retina affixed to the retinal pigment epithelium.
EL: Endolaser. This is just like typical laser retinopexy, but it’s done with a laser probe that’s inserted into the vitreous chamber and shoots the retina in a point-blank fashion. It is typically performed in a PPV after all the vitreous is removed.
C3F8/SF6/SO: Perfluoropropane/sulfur hexafluoride/silicone oil. How does the surgeon know which gas to use? How does he or she know when to use oil vs. gas? C3F8 has a longer half-life than SF6, so it will remain in the eye for a longer time and yield a longer tamponade. These are mostly positive characteristics, and many surgeons go with C3F8 for most PPVs, but there are situations when gas staying in the eye for a longer time is not necessarily a good thing. Remember that the gas bubble will negatively affect vision until it dissipates, and the patient is not allowed to get on a plane until it dissipates. So scenarios like a small retinal detachment in a patient who is monocular or really needs to get on a plane soon are times when a quicker bubble may be called for. Silicone oil actually has a weaker tamponade than gas, but the benefit here is that it doesn’t dissipate, so its tamponade effect lasts longer – months to years, in fact. Silicone oil can stay in the vitreous chamber as long as it takes to reattach the retina. It’s just that it requires another surgery to remove it.
Of course there are many more abbreviations when working with retinal surgeries, such as PFO [perfluoro-N-octane], MP [microparticle], SB [scleral buckle] and PR [pneumatic retinopexy]. Keep reading up on surgeries – even if you’re not performing them it’s important that you know every step. And don’t be afraid to ask; most retinal surgeons are pretty friendly in my experience.
Schachat AP, et al. Ryan’s Retina. 6th ed. Elsevier. 2017.