Innovations enable safe, efficient sub-2-mm phaco, IOL insertion

Washington, DC-A new ultra-small sleeve is making sub-2-mm coaxial phacoemulsification possible.

Dr. Akahoshi was not comfortable with the surge in popularity experienced by bimanual phacoemulsification worldwide, so he took things into his own hands. He thought that the bimanual procedure is slow and inefficient due to limited irrigation, low vacuum, and an unstable anterior chamber. With this procedure, he explained, the size of all the incisions exceeds that of his 2.5-mm coaxial system.

"The new sleeve is called the nanosleeve. Compared with the conventional microsleeve, it is smaller in diameter and has a thinner wall. The nanosleeve fits beautifully over the 1.1-mm Akahoshi tip. As the port is occluded by the flared tip head, the irrigation comes mainly through the large side ports laterally," Dr. Akahoshi demonstrated at the American Society of Cataract and Refractive Surgery annual meeting.

The nucleus is removed using the karate pre-chop technique. The fragments can be removed using the linear burst mode through a 1.7-mm incision, using an aspiration flow rate of 50 ml/min and vacuum of 500 mm Hg. The bent Akahoshi tip was suitable for making a complete occlusion toward the nucleus, and ultrasound energy was effectively used for phacoemulsification, he explained.

During the procedure, the followability of the nuclear fragments was outstanding as the irrigation went out through the lateral ports, Dr. Akahoshi commented. The AcrySof IOL was implanted successfully utilizing a countertraction technique and the incision size was 1.9 mm. However, a disadvantage was that the anterior chamber was unstable.

"Although the procedure accomplished phacoemulsification through a sub-2-mm incision just by changing the sleeve, it was not as comfortable as our conventional 2.5-mm surgery during which the microsleeve is used," he stated.

This resulted in a series of tweaks that led to a much improved procedure.

With the microsleeve, he explained, the irrigation flow rate is 100 ml/min and the bottle was set at a height of 140 cm. With the nanosleeve, the irrigation flow rate was 88 ml/min, because the diameter of the sleeve was smaller; this reduced flow rate resulted in the instability of the anterior chamber using his normal parameters.

Improved safety Dr. Akahoshi improved the anterior chamber stability by exchanging the cassette-infusion tube for a larger one; the inner diameter of the original tube was 3 mm and that of the larger one 5 mm. Thus, the cross-sectional area of the larger tube is three times greater and the volume is three times larger.

A piece of the drip extension tube was used to connect the large silicone tube to the original small tube from the cassette. Because the outer diameter of this extension tube was 5 mm, it fit perfectly into the silicone tube. The male connector of the tube can be inserted perfectly into the small tube of the cassette. The drip chamber of the original cassette was cut off and easily inserted into the silicone tube. Two irrigating tubes from the cassette were also cut and silicone tubes were connected by the handmade connectors, Dr. Akahoshi demonstrated.

When this irrigation cassette is attached to the Infiniti system (Alcon Laboratories), the two silicone tubes are secured with tape to prevent kinks from forming. The original male connector was cut and inserted into the silicone tube and was connected to the unit handpiece.

Dr. Akahoshi reported that there were no problems manipulating the ultrasound handpiece with the larger silicone tube. However, when the large silicone tube was connected to the irrigation/aspiration handpiece, there were some difficulties with manipulation when removing the cortex.