Plasma ablation capsulotomy: Without the need of femtosecond laser

Take-Home

A plasma blade and femtosecond laser technologies both create a perfectly round capsulotomy by plasma ablation, but any similarity between the devices ends there.

Dr. FugoBy Cheryl Guttman Krader; Reviewed by Richard Fugo, MD, PhD

Norristown, PA-Though a plasma ablation incising device (Fugo Plasma Blade, MediSURG Research & Management Corp.) and femtosecond laser are fraternal technologies with enormous synergistic capabilities for use in cataract surgery, they are distinctly different, said Richard Fugo, MD, PhD.

“Both . . . allow surgeons to create a perfectly round capsulotomy, but each has its own advantages and additional applications,” Dr. Fugo said. “Surgeons should recognize that the (blade) represents not only an alternative tool for creating a precise capsulotomy, but offers the ability to salvage femtosecond procedures that have not gone as planned.”

Dr. Fugo is the ophthalmologist-inventor of the plasma blade.

Both devices, he said, create capsulotomy by plasma ablation. For example, transferred energy shatters the molecular lattice structure of the capsule and causes transient formation of a microscopic plasma in the tissue. In fact, the FDA used the plasma blade as the predicate unit to approve femtosecond lasers for capsulotomy.

Differences

However, the plasma blade creates a “postage-stamp capsulotomy” in which the rim is characterized by a series of wavelets, Dr. Fugo said, whereas the femtosecond laser creates a smooth-edged capsulotomy.

“As noted in research¹ performed by the late David Apple, MD, the postage-stamp rim geometry is desirable for its strength and stability that make it resistant to radial tears,” said Dr. Fugo, chief executive officer, MediSurg, Norristown, PA.

Also in contrast to the femtosecond laser, the plasma blade can be used to perform capsulotomy easily, even with a highly fibrotic capsule and regardless of pupil size.

“Using the femtosecond laser, the capsulotomy diameter can be no larger than 2 mm less than the pupil diameter,” Dr. Fugo said. “For example, if the pupil enlarges only to 6 mm, the largest possible capsulotomy is only 4 mm.”

Since plasma blade capsulotomy is performed after entering the eye, surgeons can first enlarge non-dilating pupils using various stretching techniques or devices. However, it can also be done without performing any of those maneuvers, he said, as the surgeon can simply slip the handheld probe’s ultrathin cutting filament under the iris.

“I find that I perform capsulotomy by ablating under the iris in about 40% of cases,” said Dr. Fugo. “The cutting filament is not within the surgeon’s view with this technique, but it can be easily done by any surgeon who has used the (plasma blade) to perform about 20 standard capsulotomies.”

Since capsulotomy using the plasma blade is created during the main surgical procedure after the keratome incision is made, surgeons can also easily revise the capsulotomy size or shape. The device can also be used to perform a primary posterior capsulotomy, like what is done in pediatric eyes.

The plasma blade also offers a tool for salvaging cases where anterior capsule rim tears or posterior capsule tears develop. In these situations, the device is used to quickly and safely plasma ablate around the entire capsule tear.

It can also be used to ablate safely and complete an incomplete femtosecond laser-created capsulotomy, as well as enlarge or modify the shape of a femtosecond capsulotomy.

“Even if the surgeon must turn to the (plasma blade) in one in 20 cases where the femtosecond laser was used for capsulotomy, it represents a valuable parachute that will allow the surgeon to face the patient with a smile rather than with bad news,” Dr. Fugo said. “Therefore, it has positive implications for the surgeon’s emotional well-being as well as possible medicolegal ramifications.”

Both the plasma blade and femtosecond laser offer versatility, but their capabilities differ, and there are obvious differences between them in affordability and physical features.

Femtosecond lasers have other applications for cataract surgery-and some platforms can be used to make a LASIK flap or for other corneal applications-while the plasma blade also has FDA approvals for peripheral iridotomy and glaucoma filtering surgery.

In contrast to femtosecond lasers that have a fixed-floor console powered by AC wall current and cost hundreds of thousands of dollars, the plasma blade is a portable device that weighs only around 5 lbs., runs on “C” cell flashlight batteries, and sells for less than $25,000.

Reference

1.     Izak AM, Werner L, Pandey SK, Apple DJ, Izak MGJ. Analysis of the capsule edge after Fugo plasma blade capsulotomy, continuous curvilinear capsulorhexis, and can-opener capsulotomy. J Cataract Refract Surg. 2004;30:2606–2261.

Richard Fugo, MD, PhD

E: medisurgltd@yahoo.com

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