Small Gauge, high-cut advancements available for anterior vitrectomy
Upgrades in phaco platforms help cataract and anterior segment surgeons who perform vitrectomy.
Vitreous management, with the required tools and surgical skill set, should be an integral part of every cataract and anterior segment surgeon’s armamentarium in order to provide optimal visual outcome for patients after complicated cataract surgery or other anterior segment surgery, including penetrating keratoplasty and sutured or scleral pocket-fixated posterior chamber IOL implantation.
Vitreous in its undisturbed, resting state for the most part causes little visual compromise. However, when the anterior hyaloid membrane of the vitreous is violated and barriers such as the posterior capsule are accidentally torn during cataract surgery, or when ocular trauma is sustained preoperatively, the vitreous then follows via the path of least resistance and moves forward, often into the anterior chamber. This forward vitreous displacement results in the “slinky” concept, as described by Dr. Paul Koch, of being stretched anteriorly, and this can result in secondary traction in the posterior segment, namely on the retina. Such retinal traction can lead to macular edema, possible retinal detachment and compromised vision.
Cataract surgeons have traditionally performed vitrectomy through an anterior approach, but the time has come to consider a change in direction and transition to transconjunctival pars plana triamcinolone-assisted vitrectomy with a bimanual technique, in which the “slinky” will be less stretched compared with conventional anterior vitrectomy, which may contribute to an overall less amount of vitreous being removed and possibly an overall better surgical outcome. The standard approach for anterior vitrectomy is using a lower vacuum setting combined with an increased cutting rate that allows for a relatively safe vitrectomy procedure. Technological advances in phaco platforms can now offer an increased cutting rate from 600 cuts/minute to 2,500 cuts/minute, and the choice of using a 23- or 25-gauge cutter will further decrease the wound size.
While pars plana vitrectomy by retina specialists has advanced by leaps and bounds with smaller gauge instrumentation and higher cut rates, anterior vitrectomy technology has lagged behind. Most cataract surgeons are limited to the vitrectomy parameters of their phaco machines, which until recently have been 20 gauge and low cut.
Fortunately, recent upgrades in phaco platforms such as the WhiteStar Signature (Abbott Medical Optics) allow anterior segment surgeons to utilize the latest advancements in vitrectomy. Surgeons can now perform 23- or 25-gauge high-cut anterior vitrectomy without having to bring in additional specialized instrumentation. With the WhiteStar Signature, the 23-gauge vitrector comes standard (and for me has completely replaced the traditional 20-gauge cutter), while a third-party 25-gauge cutter can also be directly connected.
Advanced anterior vitrectomy
Older phaco machines limited their anterior vitrectomy to 600 cuts/minute, but the WhiteStar Signature offers cut rates up to 2,500 cuts/minute. Higher cut rates induce less traction and increase procedure safety. Furthermore, anterior segment vitrectomy has progressed from a coaxial procedure to a biaxial one, with irrigation separated from the cutter. This setup is preferred because it avoids hydrating or pushing the vitreous away from the cutting area. Using a 20-gauge cutter requires significant enlargement of the paracentesis and causes leaky wounds, but the 23-gauge cutter can fit through a 1-mm paracentesis, and the 25-gauge cutter through an even smaller paracentesis. This more watertight closure allows for better chamber maintenance with added maneuverability.
Planned or unplanned vitrectomy
While the frequency of vitreous loss during cataract surgery and unplanned vitrectomy has decreased, it is still a relatively common occurrence in the 3 million annual cataract surgeries performed in the U.S. By having a vitrectomy standard of 23 gauge and 2,500 cuts/minute, surgeons can perform a clean, efficient and safer anterior vitrectomy through any paracentesis. This prevents the frequent vitreous wicking to the wound that was commonly seen with less watertight 20-gauge systems.