Retina Today - Three Concepts to Buzz About (October 2016)

摘要

Introducing … the Squeezer By Karen Roman, Editor-in-Chief At a session titled RetinaTech: Where Surgery Meets Technology during this year’s Euretina meeting in Copenhagen, Denmark, Claus Eckardt, MD, took the podium to discuss a new device for the intraoperative injection of dyes and perflurocarbon liquid (PFCL). Dr. Eckardt began his talk by pointing out that the vast majority of surgical instruments are held using what he called the pencil grip, which in his opinion guarantees the best control of an instrument. He noted that even intraocular injections are often carried out using the pencil grip, which requires the surgeon to use his or her other hand to push down the plunger. Alternatively, he said, syringes can be held between the first two fingers to allow the thumb of the same hand to push down the plunger, although the length of the insulin syringe usually makes it difficult to stabilize the injecting hand against the patient’s head. Unfortunately, Dr. Eckardt continued, when staining agents are injected during vitreoretinal surgery, surgeons have to use this unsteady syringe grip because their other hand is normally busy with the light pipe, backflush needle, or another instrument. Furthermore, he said, the syringe grip can be risky when used in patients with small pupils because the grip makes it hard to guide the needle close to the retina. THE DYE SQUEEZER To address these and other issues, Dr. Eckardt developed a tool that he calls the squeezer to allow retina surgeons to perform injections with one hand using the preferred pencil grip. The squeezer consists of a silicone tube within a plastic frame. “Loading the squeezer with dye takes a few seconds, and it can be prepared by a nurse,” he said. Once the device is loaded, injection is performed by simply squeezing the silicone tube between the thumb and forefinger. At this point in his talk, he showed a video demonstrating how the squeezer allows perfect control over the timing, speed, and amount of dye injected. “Because it is given in such a controlled fashion, you actually use much less dye,” Dr. Eckardt noted. With the dye squeezer, surgeons can get close to the retina and suspected remnants of vitreous. The tool can be used with cannulas of all sizes: 23, 25, and 27 gauges. THE PFCL SQUEEZER According to Dr. Eckardt, another good indication for a squeezer is for the injection of PFCL. Because the volume of PFCL typically injected is much more than that of dyes, a squeezer with a longer tube had to be designed. Whereas the dye squeezer has a 1 cc capacity, the PFCL squeezer can hold up to 5 cc. Dr. Eckardt explained that the filling procedure is the same as that for the dye squeezer, and it can also be performed by a nurse. The surgeon receives the PFCL squeezer from the nurse just as he or she would most other vitreoretinal instruments. This is instead of holding the PFCL syringe with a pencil grip and potentially encountering difficulties inserting the cannula into the trocar or creating bubbles by not going close enough to the retina. Using the squeezer, he said, it is easy to guide the cannula into the trocar and to get close enough to the retina to inject a single bubble. Each squeeze of the PFCL squeezer releases approximately 1 cc, Dr. Eckardt noted. In an emmetropic eye, for example, one would need to squeeze three to four times to fill the eye to equator. He has compared the time needed to inject 4 cc using a typical syringe with that of using the squeezer, and he stated that the syringe was only a few seconds faster than the squeezer. SAFE AND DISPOSABLE Regarding whether the squeezer is safe, Dr. Eckardt said that it absolutely is—much safer than a syringe, in fact. When the squeezer is squeezed, the fluid can leave the tube only in the direction of the cannula. When pressure is released, the bottom of the tube is instantly refilled from above, so vitreous fluid can ne