June-July 2020

IN FOCUS

Ocular Surface Considerations For Surgery
Removal of primary pterygium: Techniques and other considerations


by Liz Hillman Editorial Co-Director


Large nasal primary pterygium before surgery

Four months after P.E.R.F.E.C.T. for PTERYGIUM
Source (all): Lawrie Hirst, MD

Preoperatively, this patient had a pterygium extending
2 mm onto the nasal cornea.

One month postoperatively, the patient’s conjunctival autograft is healing well with mild chemosis that will resolve over time.
Source (all): John Hovanesian, MD

 

When to take a patient to the OR for primary pterygium surgery depends on several factors. Lawrie Hirst, MD, said the indications for removal can depend on the success of your preferred pterygium surgery. For example, if you can’t promise a good cosmetic outcome, he said, you might have more stringent indications for doing surgery, which most often are visual changes and irritation.
John Hovanesian, MD, said large pterygium can be disfiguring, which is another indication for surgery. Many patients also have dry eye, causing even more irritation with the pterygium.
“You can’t fix dry eye, but you can manage it. Pterygium you can fix; you can take it out of the picture. Patients, whether they have dry eye or not, tend to have good results with pterygium surgery,” Dr. Hovanesian said.

Removal techniques

The seminal paper published more than 30 years ago by Ken Kenyon, MD, is still cited when discussing primary pterygium removal.1
“In my view the best substitute for conjunctiva is conjunctiva,” Dr. Hovanesian said, crediting Dr. Kenyon for this concept.
But the technique of conjunctival autografting for primary pterygium surgery has evolved in some ways since the 1985 paper, and there are other techniques for handling these cases.
Dr. Hovanesian described three pterygium removal techniques. He most frequently performs the classic conjunctival autograft, but it’s not his preferred technique. He said he actually gets a lower recurrence rate when he performs conjunctival autograft with an amniotic membrane, with the amniotic membrane serving as a biologic membrane surrounding the graft tissue.
Dr. Hovanesian said he reserves conjunctival autograft plus amniotic membrane for cases that are at higher risk for recurrence because there is not a mechanism to reimburse for the amniotic membrane.
The third technique Dr. Hovanesian described was amniotic membrane alone as the graft. He said this technique is not as technically difficult as conjunctival autografting, but it has a higher recurrence rate. Dr. Hovanesian reserves this technique for cases where there is not conjunctiva (due to scarring, for example) for him to harvest.
“Typically though, I don’t do that procedure because it is possible to harvest conjunctiva,” he said.
Taking it all a step further, Dr. Hirst described his intensive P.E.R.F.E.C.T. for PTERYGIUM (pterygium extended removal followed by extended conjunctival transplantation) technique for pterygium surgery, which he has shown in a prospective study to have a 0.1% recurrence rate.2 But first, he took EyeWorld on a history lesson that led to this technique’s development.
Moving back to Australia in 1986 from the U.S., Dr. Hirst said he was “astounded by the rate and size of pterygia here.” At that time, pterygia were snipped off and treated with radiotherapy. This dangerous method, Dr. Hirst said, could have severe complications, such as loss of the eye or thinning of the sclera. It’s now rarely used in Australia.
Dr. Hirst said he started using Dr. Kenyon’s conjunctival autograft technique shortly after the paper was published.
“The results were what everyone expected, between 5 and 15% risk of recurrence, and the cosmetic results were frequently horrible. That persuaded me that I needed to do something better,” he said.
Over the next decade, Dr. Hirst said he slowly expanded the quantity and quality of conjunctival autografting in his practice. One pivotal change he made was performing a large tenonectomy.
“When I did that, the recurrence rate dropped to almost zero, but as a secondary phenomenon, removing that much tenons allowed the conjunctiva to retract to its normal position, which left a huge hole.”
Dr. Hirst said he filled this hole with a large autograph (13x13–15x15 mm) from the superior conjunctiva. He sutures the graft with two radial incisions to the sclera with no tenons in between.
“Ultimately, that made sure the scar was invisible in those two areas. The only area where I still have a scar is nasally … because I’m suturing conjunctiva to conjunctiva,” he said. “The way I dealt with that was to excise the semi-lunar fold, and to use the suture line to create a new semi-lunar fold with the scar under the new semi-lunar fold.”
Dr. Hirst said he has performed more than 4,000 pterygium surgeries (3,500 primary pterygia) with this technique and has had only one recurrence following primary pterygium surgery, which he said was more than 8 years ago.
While Dr. Hovanesian said the traditional conjunctival autograft technique can take about 5 minutes in the OR, Dr. Hirst said his procedure takes upward of an hour. In Australia—and likely around the globe for that matter—Dr. Hirst said pterygium is viewed as a trivial disease deserving only a simple surgical solution. However, his technique is a complex, difficult surgery.
“In all my attempts to find ophthalmologists in Australia who wish to learn this, I’ve managed to find four,” Dr. Hirst said. However, he said that the technique’s low recurrence rate with good, predictable cosmetic outcomes makes the procedure worth it to him and his patients.

Mitomycin adjuvant

Both Dr. Hirst and Dr. Hovanesian have strong reservations about use of mitomycin in pterygium surgery. Dr. Hirst said mitomycin has its uses in ophthalmic surgery, but not for pterygium.
“It’s unnecessary and far too dangerous for pterygium surgery,” he said.
Dr. Hovanesian said that a technique that includes amniotic membrane as the graft would need to be combined with mitomycin, due to its higher recurrence rate. Even in low doses though, Dr. Hovanesian said there is risk for serious complications with mitomycin.
“Most people would agree it’s best to avoid mitomycin, but it’s what you use if you need to,” he said.

Postop regimen

Dr. Hovanesian said his use of a retrobulbar block (bupivacaine mixed with lidocaine 2%) allows the patient to be comfortable on the first night postop. He also patches the eye. The next day, Dr. Hovanesian said the patient is started on a steroid.
“I’ve had good success with Lotemax SM [loteprednol etabonate ophthalmic gel 0.38%, Bausch + Lomb] four times a day for a week, then I see them 1 week after surgery and adjust accordingly,” he said, explaining that he’ll taper over a month for low-risk patients and longer for higher-risk patients.
Dr. Hirst also said he’ll patch for the first night and advises patients wear a patch for the following 2 weeks when taking a bath or shower. He starts patients on intensive topical steroids (prednisolone every 2 hours for the next 2 weeks, then continued four times a day for a further 6 weeks). He also puts them on an antibiotic drop for a week. Dr. Hirst said patients often have pain the first night, but when the patch is removed the following day, 80% don’t require further pain medication.

Final thoughts from Dr. Hirst

Dr. Hirst had a few final thoughts regarding pterygium removal and published research on techniques. First, he said he thinks recurrence needs to be defined as any new fibrovascular growth, not just growth that manages to cross 1–2 mm over the limbus, a threshold set by many studies.
“That means that all those people where it has crossed the limbus but less than 1 mm, in these studies, aren’t a recurrence,” he said.
Dr. Hirst said patients need to be followed for at least a year to pick up on 97% of recurrences.
Finally, he added, it’s not good enough to just have a low recurrence rate.
“You’ve got to now meet the gold standard and also give patients a good cosmetic appearance,” Dr. Hirst said.

At a glance

• There are several methods for primary pterygium removal, but the most common uses a conjunctival autograft.
• Typical conjunctival autografting has a recurrence rate from 5–15%, but one surgeon published a series showing a more surgically involved technique that has a recurrence rate of less than 1%.
• Pterygium can be irritating to the ocular surface, and removal of these growths can improve some of the patient’s sensations, though it won’t resolve underlying dry eye.
• Experts did not recommend mitomycin as an adjuvant for pterygium surgery.

About the doctors

Lawrie Hirst, MD
The Australian Pterygium Centre
Queensland, Australia

John Hovanesian, MD
Harvard Eye Associates
Laguna Hills, California

References

1. Kenyon KR, et al. Conjunctival autograft transplantation for advanced and recurrent pterygium. Ophthalmology. 1985;92:1461–1470.
2. Hirst LW. Prospective study of primary pterygium surgery using pterygium extended removal followed by extended conjunctival transplantation. Ophthalmology. 2008;115:1663–1672.

Relevant disclosures

Hirst: None
Hovanesian: Bausch + Lomb, Katena

Contact

Hirst: lawrie@tapc.net.au
Hovanesian: johnhova@gmail.com

Removal of primary pterygium: Techniques and other considerations Removal of primary pterygium: Techniques and other considerations
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