Microincision cataract surgery: has bimanual had its day?
When considering surgical technique in cataract surgery, a consensus will probably never be reached on what the best method is. One of the major driving forces behind improving techniques, however, has undoubtedly been the prospect of reduced incision size.
When bimanual microincision cataract surgery (MICS), a term created by Dr Alió in 2001,2 first graced cataract surgeries some years ago, many felt that it marked a turning point in the way the technique would be performed forever. Indeed, in some ways it did in that surgeons were finally able to create very small incisions. However, despite the enthusiasm, several years on, bimanual MICS accounts for less than 10% of cataract surgeries. Surgeons faced new issues with bimanual MICS, including sub-optimal infusion, wound leakage, thermal injury, anterior chamber instability and turbulence. Importantly, IOL development had still not reached that of cataract surgery instruments; no IOLs were available that could be implanted through a sub 1.5 mm incision.
Today, there has been little change. Although IOL technology is progressing towards the bimanual MICS ideal, many surgeons feel disappointed by the complications that have been associated with the technique so far.
"…bimanual phaco has represented
one of the most important
innovations in cataract surgery
during the last decade.
Despite this, I have stopped
performing it in my routine cases"
"I do believe that bimanual phaco has represented one of the most important innovations in cataract surgery during the last decade. Despite this, I have stopped performing it in my routine cases, rather I reserve it for select cases only," admitted Dr Franchini. He now opts to perform microcoaxial surgery, which combines the principles of coaxial surgery with those of bimanual MICS to yield a technique that is simple to perform in standard cases and is associated with far fewer complications. As with most cataract surgeons, Dr Kuchynka also abandoned the bimanual technique in favour of microcoaxial surgery through a 2.2 mm incision.
"This year has certainly witnessed a change in the way cataract surgery is performed, not only with regards to the implantation of premium lenses, but thanks to new phaco machines with better ultrasound delivery systems and better fluidics control, there has definitely been a trend towards microcoaxial and microincisional surgery," said Dr Vergés.
In fact, thanks to some recent innovations in instrumentation, coaxial microincision cataract surgery (CO-MICS; Oertli Instruments) has allowed surgeons to perform coaxial cataract surgery through incisions of between 1.6 and 1.8 mm. As a result, surgeons can enjoy the benefits of bimanual's small incision size and coaxial's stable anterior chamber.
Accommodating IOLs could spur a bimanual MICS revival
Dr Alió has successfully implemented MICS technology into his practice this year by introducing the acrylic, aspheric and multifocal Acri.LISA 366D MICS IOL (Acri.Tec), the toric microincision IOLs from the same company and Bausch & Lomb's new microincision lens MI60. "Surgeons are not happy to enlarge bimanual MICS incisions to accommodate the currently available lenses. I am, however, certain that companies, such as Acri.Tec (now supported by the marketing prowess of Zeiss) and Bausch & Lomb will develop lenses that are small enough to be implanted through these microincisions. As such, I believe they will push the market towards bimanual microincision practice," predicted Dr Alió.
Dr Franchini agrees. He believes that microincision coaxial surgery has reached its final stage of evolution and he also feels that, once IOLs are developed that can be implanted through sub 1 mm incisions, the practice of bimanual phaco will become the gold standard.
Dr Faschinger, on the other hand, characterizes himself as a conservative cataract surgeon, who does not try new products, instead he prefers watchful waiting whilst admiring all new inventions. He also concedes that the little money available to his University precludes him from taking on the latest in IOL and phaco technology. In particular, he voiced his admiration for a recent study performed by Dr Rupert Menapace, in which he examined the efficacy of posterior optic buttonholing (POBH) in 500 eyes through a primary posterior capsulorhexis (PPCCC) to preserve full capsular transparency and its potential as a routine alternative to standard in-the-bag implantation of a sharp-edged IOL.3 Dr Menapace was able to successfully and safely perform surgery and avoided secondary cataract formation, leading him to predict that POBH might become a routine alternative to standard in-the-bag IOL implantation.
"I admire innovative surgical techniques such as Dr Menapace's. In addition, I visited a high volume surgeon in France recently. He performed perfect surgeries, implanting a foldable lens through a 2.2 mm incision simply by bringing the tip of the injector to the beginning of the tunnel and using a spatula in the paracentesis to counteract. I do, however, question the advantage afforded by a 2.2 mm incision over a 2.5 mm cut. Does 0.3 mm really make a clinical difference?" Dr Faschinger questioned.
All quiet on the phaco front
The procedure of phacoemulsification has changed little during the course of 2007. Alcon's introduction of torsional ultrasound in 2006, although hailed by some to be a revolution in cataract surgery, has yet to make its true mark on the global community. According to Alcon, the manufacturers of the OZil handpiece, which was introduced as a new component of its Infiniti Vision System phaco machine, in the second quarter of 2007, approximately 98% of all phaco machines it sold worldwide were equipped with the OZil handpieces, which enables torsional ultrasound phaco. Based on these estimations and Alcon's strong presence in the cataract market, maybe adoption of torsional ultrasound will be more widespread next year. Time will tell, however, in 2007, there were few new market entrants in the field of phaco technology.
Dr Faschinger concedes that, although his University does not have the funds to introduce torsional ultrasound, he is still happy with the results he obtains with the Ocusystem (Surgical Design) machine. He also uses Oertli's OS3 when combining cataract and vitreoretinal surgeries.
Still, one of the biggest issues affecting the cataract industry today, according to Dr Franchini, is the economic restriction imposed on surgeons, particularly those working in district hospitals and university departments, forcing them to use obsolete machines and to implant standard lenses. Dr Faschinger agrees to an extent although urges surgeons to look beyond the gloss of advertisements and to use evidence-based medicine to assess the true value of innovations. "Companies need to increase their profit and, although I appreciate some of the innovations that our field has witnessed, I do feel that some of the traditional approaches do still work," said Dr Faschinger.
"I was really impressed by the introduction of new software for phaco machines, which have partially changed my surgical habits this year," admitted Dr Franchini. In the past, phaco machines were hardware driven and hence required a complete shut down in order to make setting changes. Now, according to Dr Franchini, because phaco technology is software driven, not only can he change the pump that he uses during surgery, but he can also change the fluidics. "This allows me to avoid post-occlusion surge whilst increasing anterior chamber stability and I can now happily operate on the hardest and softest nuclei with peace of mind," he added.