ASRS 2018: Instrumentation Symposium

Brian Do, MD Vitreoretinal Surgery Fellow USC Roski Eye Institute The 9th Session of the 6th Annual Meeting of the Vit Buckle Society, moderated by Dr.’s Tara McCannel, MD, PhD, Emmett Cunningham, MD, PhD, and Geeta Lalwani, MD, focused on tips and tricks for various types of surgical situations, as well as on the use of various surgical adjuncts in the appropriate scenarios.

Giant Retina Rock and Roll

The first of the presenters of this particular session, Thanos Papakostas, MD, of Weill Cornell College of Medicine, demonstrated and discussed various aspects of the surgical repair of giant retinal tear (GRT) -associated rhegmatogenous retinal detachments. Dr. Papakostas suggests pars plana vitrectomy in these cases, with careful shaving/dissection of the vitreous base, removal of the vitreous gel at the posterior edge of the GRT, as well as excision of the anterior retinal flap. Additionally, Dr. Papakostas recommends the use of perfluorocarbon liquid for flattening the retina, use of a Tano scraper or Finesse flex loop to unroll the posterior edge of the GRT under PFO, and slow and meticulous fluid-air exchange at the edge of the GRT to reduce the likelihood of posterior slippage of the retina under air. While data previously published by the group at the Wills Eye Hospital demonstrated no significant benefit in long-term reattachment rates when an adjunctive scleral buckle is placed, additional data presented suggest a trend towards higher primary success with buckle placement; Dr. Papakostas indicated a preference for a low-lying buckle when an inferior GRT is present, as well as when PVR is seen. In regard to tamponade agents, there appears to be a trend towards better visual acuity with gas when compared to that when silicone oil is used. panorama-2117310_1920

Deeper Dive Into Retinal Implants

The next presentation, from Dr. Alexandra Rachitskaya, MD, of the Cole Eye Institute, demonstrated the potential benefits of newer surgical visualization platforms and adjunctive intra-operative imaging in the implantation of the Argus II Retinal Prosthesis System. Dr. Rachitskaya showed several videos, the first of which utilized a 3-D heads-up visualization system. She indicated a preference for this visualization method during Argus II implantation due to greater depth-of-field, which is helpful during creation of the sclerotomy through which the electrode array is introduced prior to placement of the retinal tack. Dr. Rachitskaya also showed that intra-operative OCT, used in conjunction with the 3D visualization system, was helpful in assessment of the macular architecture, especially in the setting of a blonde fundus. Intra-operative OCT can also allow surgeons to assess the anatomic relationship of the electrode array with the macula, which is crucial for achieving optimal visual outcome in Argus II implantation. An additional video presented exhibited a case in which intra-operative OCT was able to detect a small fragment of epimacular retained lens material, which may have interfered with apposition of the electrode array of the Argus II to the epiretinal surface had it not been detected and subsequently removed. Lastly, swept-source OCT, in the outpatient setting, appears to be capable of capturing the Argus II electrode array and demonstrating retinal apposition, even when poor fixation (expected in patients receiving the implant) would likely prevent adequate imaging using spectral domain technology.

PVD Struggles

Emmanuel Chang, MD, PhD, of Retina & Vitreous of Texas, then discussed his experience in lifting and removal of the posterior hyaloid, especially in cases of pediatric vitrectomy. He emphasized that we, as vitreoretinal surgeons, often take the vitreous anatomy for granted, especially since most of us operate primarily on adult patients. He also suggested a conservative approach to hyaloid removal in children, stating that “less is always more.” We know from histologic analysis that the hyaloid is itself a true basement membrane, and therefore a scaffold for proliferative processes – hence, the necessity of its removal. Per Dr. Chang, this is particularly true in both rhegmatogenous retinal detachments, when performing vitrectomy, as well as in diabetic tractional retinal detachments (TRD). In diabetic TRD, hyaloidal contraction may cause re-bleeding, as well as macular distortion/contraction. IMG_4449 Dr. Chang also shared his “personal rules” for hyaloidal elevation, which included: 1) avoid breaks, 2) if a break is inevitable, try to ensure that your break(s) is/are in the periphery (due to the likely loss of retinal real estate when posterior PVR develops), and 3) be patient and humble while lifting hyaloid. Additional tips included sizing instrumentation and gauging the use of vacuum appropriately, as well as careful identification and development of a surgical plane. Dr. Chang also recommends peeling the hyaloid in a direction as tangential as possible to the retinal surface, as one might when peeling a sticker off of a smooth surface. He also recommended aiming the infusion cannula posteriorly, to provide a hydrodissection effect that may aid in elevating the hyaloid as well. Instruments that can be used in various combinations for the elevation of the posterior hyaloid include the vitreous cutter, soft-tipped cannula, Tano scraper, Finesse flex loop, as well as various types of forceps. Several other pearls provided by Dr. Chang:
  • smaller gauge vitrectomy may be helpful in engaging the hyaloid edge in optically empty vitreous, e.g. Stickler’s
  • perfluorocarbon liquid may be used to exert counter-traction when dissecting the hyaloid from detached retina
  • forceps may be preferred over the vitreous cutter to peel the hyaloid peripherally from detached retina
Lastly, tips for situations in which the hyaloid simply cannot be elevated from the retinal surface:
  • Consider peeling ILM to prevent posterior macular contraction
  • Try to be as clean and complete as possible (make sure tissues are relaxed, maintain good hemostasis, use laser prudently) to minimize the likelihood and effects of PVR
  • Make sure to fill the eye with oil as completely as possible without overfilling

Viscodissection-Assisted Microincisional Vitrectomy Surgery for Management of Diabetic TRD’s

First described in Skentula and Tornquist in 1983, and later described by McLeod et al in 1988, Dr. Luis Haddock, MD of the Bascom Palmer Eye Institute introduced this technique as a helpful adjunct in delamination of fibrovascular membranes in diabetic TRD surgery. IMG_4451 Dr. Haddock indicated that while viscodissection is not necessary in most cases, there are several situations in which it can be particularly helpful:
  • Broad attachments between membranes and retina
  • Mid-peripheral / equatorial proliferation
  • Combined TRD / RRD
  • Minimal / no separation of posterior hyaloid
While this is a technique that has been adopted by a number of vitreoretinal surgeons in tackling TRD’s, there is not a great deal of literature supporting its use at this time, and we have not yet seen widespread adoption of these techniques. Dr. Haddock recommends use of the Hubbard viscodissector for these types of cases, which is easy to use, can be used with small gauge systems, is controllable with the foot pedal, and also has a flexible tip for expansion within surgical planes. His tips for intra-operative use include:
  • Finding and/or creating and opening in the posterior hyaloid to allow access of the instrument
  • Using a combination of both viscodissection-aided delamination, as well as mechanical delamination using the cannula itself (when indicated)
  • Using the cutter to segment membranes once a plane has been created
Lastly, Dr. Haddock recommends the use of cohesive viscoelastic devices. Please stay tuned for coverage of one of the first post-FDA approval deliveries of gene therapy for Leber Congenital Amaurosis by Dr. Audina Berrocal. VBS VI Coverage: 3/27/2018  VBS VI: Historic Delivery of Gene Therapy for LCA 3/27/2018  VBS VI: Surgical Adventures - Curing One Eye at a Time 3/26/2018  VBS VI: Retinaws 3/26/2018  VBS VI: Complications Session 3/26/2018  VBS VI: Women of VBS Breakfast 3/26/2018  VBS VI: Endophthalmitis Session 3/25/2018  VBS VI: Retina Caliente 3/25/2018  VBS VI: Lifetime Mentorship Award: Jay Duker 3/24/2018  VBS VI: Surgical Adventures - Bridging the Gap 3/24/2018  VBS VI: Real World Retina - Practice Management, Private Equity, Advice for Young Retina Specialists 3/24/2018  VBS VI: Medical Retina 3/24/2018  VBS VI: Live Surgery Session 3/23/2018  VBS VI: Fellows' Forray 3/24/2018  VBS VI: Welcome to Miami