Concept of ‘slow surgery’ aims for safer phaco

New philosophy championed for decreasing endothelial cell trauma.

The term “slow surgery” appears to suggest more meticulous surgery, but it is meant to challenge surgeons’ attitudes toward how they perform cataract procedures, according to a supporter of the concept.

Slow surgery actually has little to do with the duration of a cataract procedure. Rather, as Kotaro Oki, MD, explained, the term is meant to denote a sort of chivalrous view of surgery.

“The derivation of the name of slow surgery is slow life and slow food. The godfather of slow surgery is Yoshihiro Tokuda, MD, of the Inoue Eye Hospital in Tokyo,” said Dr. Oki, a Tokyo-based surgeon who formulated the concept last year. “Slow surgery is a campaign with the aim of the polite operation.”

Dr. Oki places the analogy of slow life and slow food in terms of developing good habits and showing proper respect for an experience – be it the experience of daily life, enjoying a meal or performing a cataract procedure.

Concrete criticisms

Slow surgery is not merely an abstract concept. Dr. Oki said that his concerns lie primarily with high flow and vacuum technology, which he suggested are the antithesis to slow surgery, both in action and in principle.

“High flow and vacuum surgery aims at the efficient operation, but slow surgery aims at the safe operation,” he said in an e-mail from Tokyo.

High flow and vacuum levels are inherently unsafe because they create anterior chamber instability, Dr. Oki noted. When phaco is performed with high flow and vacuum, the turbulence that is created sets off a “dangerous” chain of events, he added.

As the turbulence increases, viscoelastic is flushed from the eye, allowing the potential for nucleus fragments to collide with corneal endothelial cells and increasing the risk of injury to the endothelium, Dr. Oki explained. He said that the mean loss in endothelial cells is about 7% using high flow and vacuum technology, but a more important statistic is the potential for cell loss of more than 20%.

Even viscoelastics that are promoted as being highly cohesive, such as Healon5 (sodium hyaluronate 2.3%, Pfizer), are flushed under high flow and vacuum conditions, according to Dr. Oki.

“Slow surgery and Healon5 fit very well,” he said.

Alternate technique

Dr. Oki proposes that surgeons limit vacuum pressure to 150 mm Hg and flow rate to 20 cc/min. With lower vacuum levels, the rate of corneal endothelial cell loss can be decreased to about 2%, he said.

“[The anterior chamber] is very quiet for the [postoperative] period, when the operation is carried out at such a low set value,” he said.

Dr. Oki also expressed concerns about the phaco chop technique, which he said is also aimed at efficiency and not safety. He said proponents of slow surgery prefer the divide-and-conquer technique, which creates smaller nucleus fragments.

The key to successful slow surgery is vigorous hydrodissection, he said. With proper hydrodissection, a vacuum level of 150 mm Hg should be sufficient to emulsify the nucleus, he added.

An overview of current phacoemulsifiers in the United States suggests that most manufacturers are developing machines with vacuum capabilities of at least three or four times this amount.

Momentum

Although the concept of slow surgery is still new, the number of supporters has been gradually increasing, according to Dr. Oki. He noted that many surgeons have begun to question the merits of shorter cataract procedures.

He added that too much emphasis has been placed on the length of the cataract procedure, which he believes is already sufficiently short. As a result, many surgeons have been under pressure to use new technology, even while they have resisted “hurrying” through a cataract procedure, he said.

On the other side of the spectrum, Dr. Oki said that the emphasis on speedy phaco has become a marketing tool. He pointed to cataract surgeons in Japan who emphasize 3- to 5-minute procedures, a tactic he referred to as “regrettable.”

These comments through the mass media confuse patients by emphasizing the wrong aspects of what makes a successful procedure, Dr. Oki noted.

‘Safe and polite’

While lower levels of flow and vacuum may increase the amount of time in the operating room, the concept of slow surgery is not limited to the duration of procedure. It encompasses all aspects of a “safe and polite operation,” Dr. Oki said.

“Slow surgery is one approach, and it is one philosophy,” he said. “It is unrelated to the concept [of] time” as currently defined by cataract surgeons and manufacturers.

Slow surgery, therefore, is separate and distinct from the concepts of phaco power and phaco time, which center on how much and what sort of energy is placed in the eye.

Dr. Oki emphasized that slow surgery is being promoted as an educational initiative because a major aspect of it is teaching other surgeons about the principles of safe surgery as well as expanding their appreciation of it. Dr. Tokuda heads the educational initiative, according to Dr. Oki.

For Your Information:

• Kotaro Oki, MD, can be reached at the Oki Eye Surgery Center, 2-17-1, Ikebukuro, Toshima-ku, Tokyo 171-0014 Japan; (81) 3-3971-2598; fax: (81) 3-3986-2510; e-mail: kotaro-o@ma3.justnet.ne.jp.