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Synergetics’ 20-g cannula system


Synergetics’ 20-g Cannula System


Synergetics Inc. (O'Fallon, MO) has brought together the design technology of 1-step insertion coupled with a disposable 20-g cannula. Each cannula is preloaded onto a trocar. With an angled incision, the cannula is in place and ready to provide the surgeon with a 20-g passage to the retina.

The cannula is self-retaining in the eye and will not pull out when using different instruments, says the company. It has a slightly larger inner diameter, which allows non-angled 20-g instruments to pass through easily.

Wound architecture is considerably improved due to the razor technology used for the blade, says Gregg Scheller, president and CEO of Synergetics Inc.

The blade is beveled and has a slight step at the bottom, which facilitates insertion into the sclera and gives the cannula a tight fit. The blade is also slightly larger than normal due to its flat shape. The blade makes a longer incision at first, but ovalizes once instruments are introduced.

Because of the unique design, the surgeon will need to use a forceps to hold the cannula in place while removing the blade. Some added force is required during this motion. This blade design, especially the tip, is very delicate.

Dr. Awh is a paid consultant for Synergetics and an inventor of the 20-gauge cannulas. He does not receive royalties from the sale of the cannulas.


"The greatest benefit to this system is that it allows surgeons to operate in a transconjunctival, sutureless fashion, similar to 25- or 23-g vitrectomy, with 20-g instruments," says Carl Awh, MD, of Tennessee Retina, PC, Nashville, TN. Dr. Awh has been working on the development of the 20-g cannulas with Synergetics for at least the past 2 years.

"This device allows surgeons to use many of the instruments already present in the operating room (ie, no need to purchase new instruments)," says Dr. Awh. "A B&L 20-g fragmatome can be used through these cannulas. There is no 23- or 25-g fragmatome commercially available."

Additionally, patients have less postoperative discomfort, and the rate of postoperative recovery is similar to that achieved with smaller gauge sutureless systems (25- and 23-g), Dr. Awh says.

Operating times are reduced in many cases, Dr. Awh says, because of the increased flow of 20-g vitrectomy cutters and cannulas (compared to 25- or 23-g sutureless systems). "Compared to conventional 20-g vitrectomy with sutured sclerotomies and sutured conjunctival peritomies, the time saved is that required to open and close the eye, which in some cases can be significant," Dr. Awh says.

"In my opinion, the primary advantage of this system compared to 25- and 23- g systems is the superior wound architecture achieved by the ‘razor-edged,’ or blade-type trocar, compared to the solid or hollow core needle-type trocar of commercially available 25- and 23-g systems. This allows the use of 20-g instruments, the most robust instruments in our arsenal," Dr. Awh concludes. RP

For more information on Synergetics' 20-g cannula, please visit