No financial disclosure How do they work? Silicone tube to - PDF document

Ying Han, MD, PhD Associate Professor of Ophthalmology University of California, San Francisco No financial disclosure

How do they work?  Silicone tube to equatorial plate  IOP reduction is a function of plate surface area  Larger plate=lower IOP  350 mm 2 is likely the limit  Thickness of plate capsule  Plate material (polypropylene more inflammatory) Heuer, et al 1992, Lloyd et al, 1994 Types of Tube shunt implants  Non ‐ valved tube shunt:  Valved tube shunt:  Baerveldt  Ahmed valve  Molteno tube shunt

Indications  Refractory glaucoma:  Neovascular glaucoma  Uveitic glaucoma  Pediatric glaucoma (failed angle surgery)  Failure of trabeculectomy  Iridocorneal Endothelial Syndrome (ICE)  Eyes with prior extensive conjunctival surgery  CL wear, meibomitis, personal hygiene issues Complications  Corneal failure  Tube erosion/extrusion  Hypotony  Hypertensive phase/high rate of long ‐ term failure  Avoid complications for secondary glaucoma

How to avoid corneal complication • Angle of the tube relative to the cornea • Tube length in the anterior chamber from the point of insertion to the tip • Distance between the tip of the tube and cornea Koo, et al 2014

Regression analyses of tube parameters to predict endothelial cells loss Koo, et al 2014 Consideration  The best tube position is inserted parallel to iris  If a tube is placed pointing to cornea, the tube needs to be short  Consider cataract surgery to create more anterior chamber space  Consider sulcus placement in aphakic or pseudophakic eye  Bevel down instead of bevel up to avoid iris to plug tube

Ahmed valve surgery with Sulcus insertion How to treat tube erosion/exposure

How to treat tube erosion  Directly cover with tutoplast (donner sclera) or cornea tissue  When there is no kink of the tube  Redirect tube into sulcus  Recurrent tube exposure  Pseudophakic patient  Avoid kink of tube and pressure from eyelid  Redirect tube into vitreous cavity  Recurrent tube exposure  Require vitrectomy Tube exposure/erosion  Cover with Tutoplast/corneal tissue  Make sure there is no kink of the tube, otherwise it could erode again in 1 ‐ 2 years

Tube exposure/erosion  Reposition tube into sulcus Tube exposure/erosion  Reposition tube into vitreous cavity

How to treat hypotony Hypotony  Insert Prolene suture into the lumen of tube

How to avoid hypertensive phase and improve long term IOP control Current Regimen  Intraoperative injection of MMC (0.4 mg/ml) for 0.1ml  Postoperative injection of MMC at POW#1 and POM#1: 0.4 mg/ml for 0.1ml.  Injections are held if  IOP <5  choroidal detachment  shallow or flat anterior chamber  Timing of injection is critical – before dense capsule formation

How to avoid complications from treating secondary glaucoma Secondary glaucoma  Uveitic glaucoma  Control underlying inflammation  Non ‐ infectious uveitis: large dose of intra ‐ and post ‐ operative steroid  Infectious uveitis: regular dose of postoperative steroid  Neovascular glaucoma  Preoperative anti ‐ VEGF  Consider Micropulse TCP or ECP plus

Eye pressure in the fellow eye Problems  Elevated eye pressure during immediate postoperative period time, especially for uveitic glaucoma patients who is sensitive to steroid Jiang et al.

Summary  Insert the tube posteriorly and parallel to iris  Early use of aqueous suppression  Consider intra ‐ and post ‐ operative use of antifibrotic agents  For secondary glaucoma:  Treat underline diseases  Consider other treatments: micropulse TCP, ECP, ECP plus, TCP Thank you ！