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Thoughtful innovation

Advancing medical science through creative thinking

Dermot McGrath

Posted: Friday, December 6, 2019


Ehud Assia delivering the Binkhorst Medal Lecture at the 37th Congress of the ESCRS

The capacity to “think outside the box” and not be afraid to challenge conventional thinking represents a powerful means to advance medical science and has been the creative starting point for many key innovations in cataract surgery, said Ehud Assia MD in his Binkhorst Medal Lecture, delivered at the 37th Congress of the ESCRS in Paris, France.
“In order to come up with new ideas and innovations we often need to think differently, to approach things from a different perspective or in an unconventional way so that we can see things that we have not imagined or thought of before,” he said.
In a wide-ranging lecture, Prof Assia spoke about the power that comes from challenging conventional thinking and how this approach directly led to his own various innovations in the field of cataract surgery.
Innovation is a continuous and ongoing process, said Prof Assia, citing the amusing quote of the Commissioner of the United States patent office Charles Holland Duell who in 1889 stated that “everything that can be invented has been invented”.
“I think he got that one wrong,” said Prof Assia, noting that there are now more than 10 million patents in the United States alone and the number continues to increase every year.
Prof Assia’s own research has sought to develop new surgical devices and technologies by considering issues from different angles and with a non-conventional view.
One such example is the side-view technique that Prof Assia developed with Dr David Apple as a new method for studying the anterior chamber anatomy in post-mortem eyes.
The problems encountered by lens subluxation, usually managed by capsule-stabilising devices such as Cionni Ring and its modifications or capsule hooks, also prompted Prof Assia to develop an alternative approach using a capsular anchor (Hanita Lenses).
The anchor comprises a central rod placed in front of the anterior capsule and two lateral prongs placed under the anterior capsulorhexis edge, with the tips of the prongs extending to the capsule equator to provide localised support. A new second-generation version of the anchor is currently under development, he said.
Prof Assia cited yet another example of innovation, which came from dealing with small pupils during cataract surgery. Instead of iris hooks or iris-expanding rings such as the Malyugin Ring, he proposed a pupil expander that uses two spring-loaded devices inserted through 1.1mm sideport incisions opposite each other to create a rectangular pupil opening and facilitate surgery.
Dr Assia devoted the greater part of his lecture to his research efforts to improve fluidics during phacoemulsification, with an emphasis on maintaining corneal endothelial safety.
“There is so much more than we can do to improve phaco fluidics if we are prepared to just think unconventionally about the problems involved,” he said.
He noted, for example, that phaco surgery depends largely on fluid irrigation and maintaining the volume of the anterior chamber and intraocular pressure, usually with a passive irrigation of fluid (BSS) delivered through the machine handpiece.
“This has not changed in the last 50 years since the early days of phacoemulsification. And it works well in keeping a stable anterior chamber and intraocular pressure, but only as long as the phaco tip is in the eye. Once we pull the tip out, the pressure drops and the chamber can collapse until we reinsert the irrigation line to re-establish the pressure,” he said,
Maintaining a stable anterior chamber and IOP during surgery requires continuous irrigation throughout surgery, said Prof Assia. He proposed that this separate irrigation line would be the sole fluid source for the surgery which could be performed through a 1mm incision when 1mm IOLs eventually become available, he added.
“My idea was to identify a method for maintaining steady pressure throughout surgery, independent of the phaco handpiece, and utilising an automated pump to achieve continuous active maintenance of anterior chamber pressure,” he said.
Such an approach combines the advantage of active fluidics and the stability of an anterior chamber maintainer and works well with Prof Assia’s novel three-port mini-incision phaco technique (Tri-MICS).
Prof Assia also proposed using a diluted viscoelastic substance, instead of BSS, to give “slow motion” protection to the endothelium.
“This would provide a comfortable surgical environment with low turbulence to protect the corneal endothelium. The advantage is that it its use would not be restricted to phacoemulsification but could also be used in vitreoretinal or glaucoma surgery as required,” he said.
The new diluted viscoelastic substance could also incorporate ascorbic acid as a non-toxic free radical scavenger to protect against corneal endothelial damage caused by ultrasound energy-generated free radicals.
“Phaco energy generates free radicals that initiate the process of apoptosis and programmed cell death. We have carried out extensive animal studies that show that free radical scavengers added to the phaco fluid may protect cells from chemical damage,” he said.

Ehud Assia: assia@netvision.net.il