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When the Sides Collide

On Managing Crossover Complications

Although the anterior and posterior are two distinctly different segments, surgical complications can sometimes blur those lines of separation. Therefore, it’s critical that vitreoretinal surgeons not only recognize potential risk factors but can also manage complications that may arise in the front of the eye. 

This important topic was explored in a symposium called “Management of Anterior Segment Surgery Complications,” at the recently held 2018 Asia-Pacific Vitreo-retina Society (APVRS) congress in Seoul, Korea. Below, we look at some of the most important take-home messages from that symposium.

Regarding silicone oil removal and IOP

Based on a presentation called “Incidence and Management of Elevated Intraocular Pressure After Silicone Oil Removal” by Dr. Miho Nozaki, from Nagoya City University’s Department of Ophthalmology and Visual Science, Japan.

If silicone oil (SO) is not removed completely following retinal surgery, it can leave a nasty little reminder behind – in the form of elevated intraocular pressure (IOP). 

In a previous study, Dr. Nozaki reported that 21.7% of patients experience elevated IOP following SO removal using a 20- to 25-gauge system. This led her team to another study – this time, they would record the incidence of IOP using only a 25-gauge system. Would a smaller gauge make a difference?

It turns out, it did. In their latest study 16 of 61 eyes experienced elevated IOP during SO tamponade; and following SO removal, 11 of those 16 eyes returned to normal IOP.  This led the researchers to state that overall, 9.8% of eyes had elevated IOP following the procedure. 

Regarding SO removal, Dr. Nozaki suggests using the viscous fluid controller (VFC) system with fluid-air exchange. She also highlighted feedback from other experienced Asia-Pacific surgeons, many of whom prefer using the VFC system.

She and her team concluded that the duration of SO tamponade was significantly longer in the elevated IOP group – therefore the duration should be limited to three to four months. In addition, the likelihood of SO migration to the anterior chamber is more likely in IOP elevated eyes.

Choosing cases for combined cataract and vitrectomy surgery

Based on a presentation called “Combined Cataract and Vitrectomy Surgery: Pros and Cons” by Dr. Doric Wong, adjunct associate professor and senior consultant from Singapore National Eye Centre (SNEC).

According to Dr. Wong, the co-existence of cataract and retinal pathologies can occur – especially in older patients, whose cataract has been accelerated by intraocular procedures, like vitrectomy. Therefore, in certain cases, he suggests combining cataract and vitrectomy surgeries into one: phacovitrectomy. 

In his presentation, he discussed a few scenarios where this combined procedure would be ideal – for example, in patients with macular holes, myopic macular retinoschosis or with “simple” vitreous hemorrhage. 

In these instances, he says that phacovitrectomy has several advantages: it shows a better outcome; it helps decrease costs by avoiding two separate surgeries; and it reduces the number of visits, which saves patients’ time off work. 

“The procedure would also be useful for treating posterior polar cataracts,” noted Dr. Wong. 

Of course, the combined procedure may not be ideal for all patient cases. Dr. Wong notes that there could be potential complications in patients with iris neovascularization in diabetic vitrectomy, or those with intraocular lenses (IOLs). Therefore, Dr. Wong suggests that surgeons first perfect the phacovitrecomy technique and then choose patient cases wisely.

On managing dislocated IOLs

Based on a presentation called “Management of Dislocated IOL”, by Dr. Andrew Chang, from the Retinal Unit Sydney Eye Hospital, Australia.

A dislocated IOL is an unfortunate complication of cataract surgery. When this occurs, surgeons must consider several factors to manage and correct the problem.

Dr. Chang explained that there are several replacement options for dislocated IOLs, including one-piece IOLS, three-piece IOLs and anterior chamber IOLs (ACIOL). He advised that when selecting the replacement IOL, surgeons take into consideration the degree of capsule support required, as well as the skill and comfort level of the surgeon in each approach.

In addition, Dr. Chang explained that scleral fixation options can be used – including suture and suture-less options, noting that Prolene sutures were prone to breakage. However, he offered a tip learned from another surgeon to remedy these breaks: “If you tie the suture with two sutures in a one knot technique (within the scleral flap), it could last up to 25 years, with only a 0.5% breakage rate.”

When endophthalmitis strikes

Based on a presentation called “Updates on the Prevention and Management of Post-Operative Endophthalmitis” by Dr. Manoharan Shunmugam, a Paediatric Vitreoretinal Surgeon at Pantai Hospital Kuala Lumpur in Malaysia.

Endophthalmitis is a severe complication of ocular surgery. Fortunately, it occurs rarely following surgery, affecting 0.03 to 0.70% of cataract patients; 0.2 to 1.5% of glaucoma patients; and 0.052% of vitrectomy patients.

However, he notes there is also a risk of developing endophthalmitis through other procedures, like intravitreal injections: “Being prone to endophthalmitis after intravitreal injections is something we’re hearing more of, sometimes with devastating effects, so we need to be aware of this,” he explained.

It has various risk factors, including: local factors like blepharitis; systemic factors like diabetes renal disease; and intraoperative complications such as posterior capsule ruptures or vitreous loss. Dr. Shunmugam also says that longer surgeries pose an increased risk – he says that after 45 minutes, endophthalmitis could develop. 

Cleanliness and hygiene are key measures to prevent endophthalmitis. “Be careful about factors within the clinical environment – this includes air-conditioning, solutions and medications, surgical instruments, gloves and face masks, as well as tissues like skin, lashes and mucus,” cautioned Dr. Shunmugam.

If a patient develops endophthalmi-tis, they must be monitored and treated immediately. So, how do we treat it? Dr. Shunmugam shared insights from the recent Complete and Early Vitrectomy for Endophthalmitis (CEVE) study, which concluded that patients should not be operated on too early: If there’s good red reflex, or some visible retinal details, treat it with intravitreal antibiotics and corticosteroids and monitor it closely. If there’s no improvement, no red reflex and no red retinal visibility, then a complete vitrectomy should performed, regardless of visual acuity. (This is in contrast with older protocol suggested by the Endophthalmitis Vitrectomy Study (EVS), which prescribes early vitrectomy surgery to treat postoperative endophthalmitis.

Insights in choroidal complications

Based on a presentation called “Management of Choroidal Problems” by Dr. Sung Soo Kim, a professor at the Department of Ophthalmology at the Institute of Vision Research at Yonsei University College of Medicine, Korea.

Dr. Kim defines choroidal effusion (either serous or hemorrhagic) in two ways: as the clinical observation of abnormal serous fluid in the ciliary body and choroid; or the condition with abnormal accumulation of serous or blood in the suprachoroidal space. Any condition that results in low IOP can be considered a risk for choroidal effusion development – this includes: glaucoma surgery, and systemic and topical medications, among other factors.

He iterated that acute or chronic hypotony after ocular surgery may induce critical choroidal effusion and suprachoroidal hemorrhage in patients with risk factors such as old age, those on anticoagulants or high myopia, among other conditions. 

That’s why, according to Dr. Kim, a big part of management lies in prevention including reducing preoperative IOP; using medication to optimize perioperative heart rate and blood pressure; ceasing anticoagulant medication and observing intraoperative and postoperative hypotony control. Medical management, with the use of topical or systemic steroids, cycloplegics and analgesics has been recommended.

To manage vision threatening postoperative choroidal complications, he suggests that physicians identify the reason for hypotony, control inflammation, and choose the proper technique for effusion and treat concurrent vitreoretinal complications. 

In addition, other presenters described other instances of posterior-anterior crossover – including cataract surgery in cystoid macular edema (CME) to a dropped nucleus – and provided tips to resolve each complication. 

Overall, it’s safe to say that the main take-home message was this: When vitreoretinal surgery causes an anterior issue, it’s critical that surgeons anticipate and recognize signs and that they are proactive in treatment, despite lack of guidelines or standardized therapy (in some cases). 

Editor’s Note: The APVRS 2018 Congress was held in Seoul Korea, on December 14-16, 2018. Media MICE Pte Ltd, PIE Magazine’s parent company, was the official media partner of APVRS 2018. Reporting for this story also took place at APVRS 2018.

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