Glaucoma Drainage-Device Surgery Pf. 박찬기/R3.염혜리

Open-Tube Drainage Device Baerveldt Molteno Schocket Flow-restricted Drainage Device Ahmed Krupin

Molteno Krupin Ahmed 1973 1976 1981 1992 1993 Baerveldt Double plate Molteno Molteno Krupin Baerveldt Ahmed 1973 1976 1981 1992 1993

Baerveldt Implant In 1992 Non valved silicone tube + soft barium-impregnated silicone plate (surface area: 250mm2, 350mm2) Fenestration: allow growth of fibrous tissue, reduce height of bleb -> reduce the risk of diplopia & help to secure Under rectus m. at superotemporal Q

Baerveldt Implant Indication NVG PPKP c glaucoma RD surgery with glaucoma ICE synd. Traumatic glaucoma Uveitic glaucoma Previous failed trabeculectomy Epithelial downgrowth Refractory infantile glaucoma

Fibrous capsule : post op. 3~6wks IOP<21mmHg : 87%(350mm2) Success rate : 79 %(350mm2) at 5 yrs 350mm2 implant similar to double plate Molteno & Ahmed valve lowering IOP FU 1yr & 4yrs -Syed et al. and Tasi et al. similar to trabeculectomy with MMC for IOP control and avoiding hypotony & reoperation FU 1 yr -Gedde et al.

Molteno Implant In 1973 : prototype device Polypropylene plate + silicone tube Single plate(137mm2) : outer circular ridge containing a triangular pressure ridge In 1981, Double plate Molteno implant : increase surface area(274mm2): success rate 25~46% -> 40~71%, Molteno 3: single plate (175mm2, 230mm2), thinner & more flexible plate and elliptical pressure ridge, limiting the available area of filtration during low aqeous production

Molteno Implant Indication Infantile and juvenile glaucoma Aphakic or pseudophakic glaucoma Traumatic glaucoma Uveitic glaucoma Glaucoma secondary to previous intraocular surgery Neovascular glaucoma Failed previous trabeculectomy Complications of trabeculectomy on fellow eye

Outcome Baerveldt versus double-plate Molteno :similar reduction in IOP (greater than 44%), success rates, and visual outcomes with almost 1 year of follow-up - Smith et al. Ahmed versus double-plate Molteno: Molteno produced a statistically significant lower IOP at 12 and 18 and lower risk of developing a hypertensive phase(43.5%) compared with the Ahmed(83.5%). ultimate success rates that were similar (approximately 50%) at 24 months. -Ayyala RS et al.

Schocket tube shunt 360-degree silicone band(reservoir for aqeuous drainage)+silicone or silastic tube Modification: 90 degree beneath 2 rectus m. Schocket tube vs double plate Molteno : lower final IOP-double plate Molteno

Open tube drainage Cx. ) hypotony, flat anterior chambers, and choroidal effusions To prevent hypotony d/t lack of outflow resistance ligate the tube with dissolvable suture: dissolve in 6-8wks(fibrous capsule formed around the plate providing some resistance) thread a suture into the tube to obstruct implant 2 stage: 1) end plate implant 2) tube implant after forming the capsule

Krupin Implants produced in 1976 oval silastic disc(13mm x 18mm)+tube pressure sensitive unidirectional valve to provide resistance to outflow and prevent post op.hypotony Valve effect: making slits in the closed ext. end of the tube open at IOP 11mmHg & close at IOP 9mmHg 113 eyes: transient post op.hypotony-3 eyes chronic hypotony-1 eye

Other

Ex-PRESS Ex-PRESS glaucoma drainage divice 3mm long stainless steel tube without external plate excellent biocompatibility implant under a traditional trabeculectomy flap or scleral flap IOP 27.2±7.1mmHg ->14.5±5.0mmHg over 12months -Dahan et al.

Solx Gold Shunt Solx Gold Shunt: 3x6mm sized 24K gold that connect the AC & suprachoroidal space-> no subconj.drainage(no bleb)

iStent iStent trabecular microbypass stent stainless steel stent Undergoing cataract surgery delivered ab interno through a clear corneal incision, advanced through the trabecular meshwork and implanted into Schlemm canal for aqueous humor to drain directly from the anterior chamber into Schlemm canal avoids any manipulation of the iris, conjunctiva, or sclera

Outcome No statistical difference according to the surface area of plate Maximum end-plate area to achieve IOL lowering with additional surface area

Outcome The success rates : about 70% of mean IOP lowering at least 50% from the pre op (all) The failure rates : about 10% per year, leading to only 50% functional drainage devices at 5 years.

Long term outcomes More than 12 months Success: low end cutoff- 5~6mmHg, high-end cutoff-21~22mmHg c/s medication Molteno: 73~74 %(18mo), 57%(43~44mo) 76% in uveitic glaucoma(5~10yrs) 72% in black patients(30mo) Double plate> single plate Failure: m/c in 1st post operative yr Failure increase in pseudophakia & NVG

Schocket-type drainage device Baerveldt implants 91%(10mo), 81%(17.5mo), 30%(36mo) Baerveldt implants 93%(350mm2)(18mo) 71%(2yr) Krupin eye valve & disc 84%(6mo)m 66%(12mo) 80%(25mo) Ahmed drainage device 77~87%(1yr), 75%(2yr)

Complications Early postoperative hypotony Diplopia Tube extrusion No valve mechanism Ahmed valve:8~13%, Krupin valve: 8% Diplopia Highest with the Baerveldt implant(3~18%) (large size & shape, ins.underneath the rectus m.->direct disturbance, scar formation, height of the bleb) Tube extrusion infection

Causes of Failure Bleb encapsulation(early), fibrosis(later) Two stage of bleb Hypotensive phase: 1st lasting 1-4wks diffuse edema, congestion of blood vessel in the tissue covering the episcleral plate of implant Hypertensive phase: >21mmHg, begins 3-6wks, last for months, definite layer of fibrous tissue at deepest layer of bleb capsule Hypothesis Glaucomatous aqeuous lead to fibroproliferation

GDD as Drug Delivery System end-plate: reservoir for drug Tube: instead of draining aqeous, deliver drug from end-plate into the eye via one-way pressure-dependent valve External pr.>cracking pr. of one way valve Limitation Mark Humanyan: wireless programming system (accuracy rate of±2%)