EyeWorld Asia-Pacific June 2018 issue

Adopting MIGS into practice by Ellen Stodola EyeWorld Senior Staff Writer AT A GLANCE • Most surgeons agree that there is a learning curve associated with MIGS, and this often involves making sure you’re familiar with intraoperative gonioscopy and angle anatomy. • Several surgeons noted that they use a Swan-Jacob gonio lens when doing intraoperative gonioscopy. • MIGS may be a particularly good option for cataract and refractive surgery patients because of its microinvasive nature. On the learning curve, barriers to adoption, and how comprehensive and refractive surgeons can use MIGS W ith the approval of many new MIGS de- vices in the past sev- eral years, surgeons choosing to incorporate them into practice must consider the learning curve that comes with each device and the skillsets needed to develop expertise with these procedures. Linda Huang, MD , Glaucoma Institute of Northern New Jersey, Rochelle Park, New Jersey, Thomas Samuelson, MD , Minnesota Eye Consultants, Minneapolis, Jacob Brubaker, MD , Sacramento Eye Consultants, Sacramento, Cali- fornia, and Michael Patterson, DO , Eye Centers of Tennessee, Crossville, Tennessee, shared their views on the MIGS learning curve and highlighted considerations for comprehensive and refractive sur- geons wanting to use these devices. Some MIGS procedures include the iStent (Glaukos, San Clemente, Cali- fornia), XEN Gel Stent (Allergan, Dublin, Ireland), and CyPass Micro- Stent (Alcon, Fort Worth, Texas). MIGS learning curve There is a learning curve for adopt- ing MIGS, Dr. Huang said. “Many procedures involve the angle, and intraoperative gonioscopy is a skill that is not commonly used in the operating room,” she said. “Rec- ognizing and identifying angle anatomy intraoperatively is also a skill to develop.” Dr. Huang added that once these two are mastered, they can be applied to many MIGS devices. “Then there are specific skills unique to individual devices, but mastery of one device usually translates to other devices.” Dr. Patterson agreed that there is a learning curve, particularly in making sure that physicians are capable of understanding the angle and are proficient at doing intraoperative gonioscopy. “That is a totally different animal for MIGS surgery than it is in the clinic,” he said, adding that if you can under- stand placement and anatomy of the angle, you’re pretty much set. Dr. Patterson is a big proponent for doing preoperative gonioscopy. A lot of ophthalmologists rely on optometrists or outside providers to do the preoperative exam, he said, but then you don’t know what you’re looking at when you get into the OR. The biggest learning curve with MIGS is using the gonioprism for good visualization of the angle structures, Dr. Brubaker said. “The other challenge that can be dif- ficult initially is that the surgeon is restricted to using only one hand in the eye while the other hand is oc- cupied holding the gonioprism,” he said. Most surgeons learning MIGS begin with trabecular meshwork- targeted procedures like the iStent, Dr. Brubaker said. “Although the iStent has a slightly longer learning curve than some of the other MIGS, I think this is a good place to start,” he said. “This procedure has a lower risk profile than other MIGS.” He noted that the “trick” with iStent placement is ensuring that the stent is well seated in the canal and not placed too superficially. “I think this takes 10–15 cases to get a com- plete feel for proper placement,” he said. Dr. Brubaker added that from a placement standpoint, he thinks the CyPass has the shortest learning curve. “The gonioscopic challenge with CyPass is that the surgeon has to make sure to not press down on the lip of the corneal wound during placement,” he said. “Because the CyPass is inserted in the more pos- teriorly located supraciliary space, the surgeon needs to raise the wrist and the handle of the inserter to prevent downward force on the cor- neal lip.” Dr. Brubaker said that this helps to avoid distortion of the cor- nea, making visualization difficult. “Another challenge with the CyPass is recognizing differences in iris root appearances among patients,” he said. “Rather than focusing on the apparent insertion of the iris at the more posterior root, it is crucial to target insertion of the CyPass just below the scleral spur.” This is a constant anatomic feature that can reliably direct CyPass placement in every case, he said. With the other trabecular meshwork targeted MIGS such as gonioscopy-assisted transluminal trabeculotomy (GATT) and Kahook Dual Blade (KDB, New World Medi- cal, Rancho Cucamonga, Califor- nia), one can rely on the techniques used in learning the iStent, Dr. Brubaker said. “A good feel for the location and depth of the mesh- work and canal are particularly helpful during one’s progression to- ward these more advanced MIGS,” he added. “Both of these procedures require the use of interocular micro- incision forceps under gonioscopic visualization.” He added that this is a technique that can be helpful in these procedures but also if reposi- tioning is necessary with CyPass or iStent. Finally, Dr. Brubaker said that the use of the XEN Gel Stent is on a different spectrum when compared to internal MIGS. “The (indirect) gonioprism is only used to guide initial targeting of the needle,” he said. “The stent is injected with direct visualization.” He added that the learning curve with the XEN is making sure the stent is well placed. Advanced placement just under the conjunctiva is a technique that usu- ally requires more than a handful of cases before this can be mastered, Dr. Brubaker added. continued on page 36 September 2017 June 8 EWAP SECONDARY FEATURE 35