PAID ADVERTISEMENT FROM ALCON

Why You Should Be Using Valved Cannulas

Learn how one seemingly small modification has advanced vitreoretinal surgery

Skeptics and naysayers, take note. Miami retina specialist Timothy G. Murray, MD, MBA, once counted himself among your ranks when the discussion turned to valved cannulas. “I must admit, when we first discussed valved cannulas, before I had used them, I felt it was a relatively small improvement in the system and essentially unnecessary,” he says. “I like to think I don’t get things wrong too often, but I must say I truly did not appreciate valved cannulas until I had the opportunity to use them. Essentially, I went from having no interest in them to using them exclusively in virtually 100% of my cases. Placing a valve in a cannula, in my opinion, is one of the most significant advances in fluidic stabilization of the eye.”

Carl D. Regillo, MD, director of the retina service at Wills Eye Hospital in Philadelphia, agrees with that assessment. “For each and every case, whether simple or complex, I can think of at least one seemingly small advantage that makes using valved cannulas worthwhile,” he says. “Cumulatively, those small advantages create a very controlled, very gentle, more physiologic intraocular environment.”

We asked both surgeons to discuss how using the EDGEPLUS^® Valved Trocar Cannula System has improved their intraoperative experiences.

CONTROL OF FLUIDICS

Controlling intraocular pressure is a constant concern during vitreoretinal surgery, and the valved trocar cannula is first and foremost about control. “What I appreciated immediately with the valved cannulas is how much easier it is to put them into the eye,” Dr. Murray says. “If I start with a pressure of 20 mmHg and place 3 valved cannulas into an eye, I know when I’m done, the pressure will be 20 mmHg. That’s the big pivot point between valved and non-valved cannulas.”

What’s more, Dr. Regillo says, valved cannulas complement and optimize the IOP compensation technology of the CONSTELLATION^® Vision System. “With the CONSTELLATION^®, we can regulate the flow into the eye, essentially delivering the pressure we need,” he says. “Valved cannulas enable us to regulate the flow out of the eye. What goes into the eye is minimized, and what comes out of the eye is minimized. It’s the perfect marriage. We avoid having fluid gushing through the eye and out through a non-valved cannula, creating a potentially detrimental situation, especially in more time-consuming cases.”

Dr. Murray agrees. “When the sclerotomy sites with non-valved cannulas are open, you’re continuously pushing fluid from the infusion cannula into the eye and out the open port,” he says. “That is a significant disadvantage. You have the potential to incarcerate vitreous; you have the potential to incarcerate retina when pulling an instrument up and into the space.”

Dr. Murray notes initial concerns that small-gauge surgeries using transconjunctival trocar cannula systems would increase the incidence of peripheral retinal tears have been unfounded. “In fact, for me, it’s been exactly the opposite,” he says. “Part of the reason for that is because valved cannulas don’t allow fluid reflux from the eye. It decreases the likelihood of traction that sometimes occurs near our sclerotomy sites. This can be an additional benefit of the cannulated trocar system and the use of the valve.”

SMOOTH INSTRUMENT EXCHANGES

In addition to providing a closed system for IOP control, the EDGEPLUS^® Valved Entry System facilitates smooth instrument exchanges and eliminates the need for sclerotomy plugs. “Plugs can be a hassle,” Dr. Regillo says candidly. “Plugs can pop out or get lost. Plugs may get dropped or left in the cul de sac of the eye. Using them can be time-consuming and disrupt the rhythm of the surgery. Now, instead of removing an instrument, inserting a plug, removing the plug and reinserting the instrument, I can easily enter and exit the eye through the valved cannula, even with bi-functional instruments, such as curved endoprobes. The low-friction silicone valves are designed for smooth exchanges. This makes for a tremendously efficient, smooth surgical procedure.”

Dr. Murray notes, “Any time an instrument comes out of the eye for any reason, whether you change hands for the cutter or you exchange a cutter for a forceps or a scissor, the fundamental difference between valved and non-valved cannulas is apparent in how the eye maintains the fluid pressure and how the fluidics function during those exchanges.”

COMPLEX CASES

Both surgeons use the valved trocar cannula system for all of their cases, even the most complex.

“I perform many combined phaco/vitrectomy surgeries,” Dr. Murray says. “Valved cannulas have an added benefit for combined procedures. I can place my cannulas before performing the anterior segment surgery without compromising the intraocular fluid volume.”

Dr. Regillo notes, “The valved cannula can be a tremendous advantage over the open wounds of the past, especially during complex cases (for example, those involving diabetic eyes and complicated retinal detachments) where you’re exchanging fluids, potentially using oil, and maneuvering within the eye. Nothing’s worse than having perfluorocarbon liquid (PFCL) bubble up and obscure your view. Now, I can carefully regulate fluids going in and out of the eye.”

Prior to using valved cannulas, Dr. Murray would routinely use one and sometimes two vials of PFCL during a complicated case. Many cases required two vials of PFCL when complex pathology was present. “In a valved cannula system, you don’t unintentionally lose any of the PFCL,” he says. “Our success as microsurgeons has everything to do with control and our ability to stabilize the tissue plane, to maintain IOP, to understand how the fluid moves in and out of the eye, and that movement really should be through your vitrectomy probe/aspiration port only.”

Some perioperative challenges have also decreased. “In the old days, before valved cannulas, we’d remove an instrument from an open wound and the fluid would stream out, dousing the microscope, the lens systems, even our clothing,” Dr. Regillo says. “At the end of every oil case, our instruments were slick with oil and difficult to handle, and we’d need to rinse the eye. These may seem like minor nuisances, but eliminating them creates a preferable environment.”

ENHANCED PROCEDURE

“By using valved entry systems, we have fundamentally improved our surgical procedures and standardized the fluidics within the eyes on which we’re operating,” Dr. Murray says.

Dr. Regillo believes widespread adoption of valved cannula systems will have a significant impact on complications. “On a more routine basis, our operations will be smoother and more efficient. In my opinion, there’s every reason to use valved cannulas for the full spectrum of cases, from the simplest to the most complicated.”

Dr. Murray is a paid consultant for Alcon.
Dr. Regillo is an advisor to Alcon.

MIVS Important Product Information

Caution: Federal law restricts this device to sale by, or on the order of, a physician.

Indications for Use: The CONSTELLATION® Vision System is an ophthalmic microsurgical system that is indicated for both anterior segment (i.e., phacoemulsification and removal of cataracts) and posterior segment (i.e., vitreoretinal) ophthalmic surgery.

The ULTRAVIT® Vitrectomy Probe is indicated for vitreous cutting and aspiration, membrane cutting and aspiration, dissection of tissue and lens removal. The valved entry system is indicated for scleral incision, canulae for posterior instrument access and venting of valved cannulae. The infusion cannula is indicated for posterior segment infusion of liquid or gas.

Warnings and Precautions:

• The infusion cannula is contraindicated for use of oil infusion.

• Attach only Alcon supplied products to console and cassette luer fittings. Improper usage or assembly could result in a potentially hazardous condition for the patient. Mismatch of surgical components and use of settings not specifically adjusted for a particular combination of surgical components may affect system performance and create a patient hazard. Do not connect surgical components to the patient’s intravenous connections.

• Each surgical equipment/component combination may require specific surgical setting adjustments. Ensure that appropriate system settings are used with each product combination. Prior to initial use, contact your Alcon sales representative for in-service information.

• Care should be taken when inserting sharp instruments through the valve of the Valved Trocar Cannula. Cutting instrument such as vitreous cutters should not be actuated during insertion or removal to avoid cutting the valve membrane. Use the Valved Cannula Vent to vent fluids or gases as needed during injection of viscous oils or heavy liquids.

• Visually confirm that adequate air and liquid infusion flow occurs prior to attachment of infusion cannula to the eye.

• Ensure proper placement of trocar cannulas to prevent sub-retinal infusion.

• Leaking sclerotomies may lead to post operative hypotony.

• Vitreous traction has been known to create retinal tears and retinal detachments.

• Minimize light intensity and duration of exposure to the retina to reduce the risk of retinal photic injury.

ATTENTION: Please refer to the CONSTELLATION^® Vision System Operators Manual for a complete listing of indications, warnings and precautions.