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 mm2 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

 Valved tube shunt:

 Ahmed valve

 Non‐valved tube shunt:

 Baerveldt  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‐

• perative 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！