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COPE 28464-GL - Advances in Glaucoma Surgery (2hrs)
This course can be shortened to one hour but I would only discuss SLT/ECP, the new angle surgeries (Icanaloplasty, trabectome etc.) and limit the section on trabs and shunt tubes.
ABSTRACT
In spite of our many and varied pharmaceutical options for glaucoma treatment, some
patients don’t respond. In these cases, surgical intervention may be required. This
course discussion will include glaucoma laser procedures (SLT/ECP), filtering surgeries (trabeculectomy,
shunt tubes, express mini shunt) and the newest angle surgeries (I-canaloplasty, trabectome, I-stent).
Video presentations of surgical techniques, patient considerations and postoperative co-management will
be highlighted.
OUTLINE
1) Decision to Operate
a) Inadequate IOP control on maximum tolerated meds
b) Poor compliance with meds
c) Progressive ONH cupping and/or VF loss despite well controlled IOP
d) Surgery is primary approach in pediatric or pupillary block glaucomas
2) Patient Expectations
a) Arrest progression of ONH damage and VF loss
b) No visual improvement
c) Possible continued need for anti-glaucoma meds
3) Risk of complications
a) Visual loss
b) Surgical failure
c) Specific risks dependent on type of surgery
4) Choice of Procedure
a) Laser surgery
b) Iridotomy
c) Argon Laser Trabeculoplasty
d) Selective Laser Trabeculoplasty
e) Endocyclophotocoagulation
f) Filtering Surgery
g) Trabeculectomy
h) Shunt Tube Surgery
i) Ex-Press Mini filter
j) Angle Surgery
k) Canaloplasty iScience
l) Trabectome
m) iStent
5) Choice of Procedure- Other considerations
a) IOP Goal
b) Age
c) Race
d) Life expectancy/general health
e) Socioeconomic factors
f) Living arrangements
g) Ability to follow post op instructions
h) Personal hygiene
i) Status of other eye
6) Selective Laser Trabeculoplasty
a) Extrapolated from Argon Laser Trabeculoplasty (ALT)
b) YAG Laser- not Argon
c) 532nm wavelength
d) 3 nanosecond pulse
e) Selectively targets pigmented cells in TM where ALT is nonselective
f) Activated cells release cytokines that trigger a targeted macrophage response to the TM
g) Macrophages phagocytize matter in the TM increasing outflow
h) Heat diffusion confined to melanin-containing cells
i) Unlike ALT where ALT has:
(1) Permanent damage (same laser as focal/PRP)
(2) Peripheral Anterior Synechia (PAS)
(3) IOP spikes common (mild)
(4) Not repeatable
(5) 360 degree treatment common
(6) Can do 2 non-overlapping 180 degree treatments
(7) Coagulative damage as seen with ALT is a significant disadvantage
i) Laser pulse less than thermorelaxation time of cells
j) Thus cells don’t have the chance to turn laser energy into thermal energy
k) ALT causes crater formation, coagulative damage, fibrin deposition and disruption of
trabecular beams and endothelial cells
l) SLT does not show these findings
m) SLT's effect occurrs intracellularly, with disruption of the melanin granules
n) Thermal transfer indicated in red
o) SLT shows only melanin containing cells with thermal absorption
7) Video of SLT here
8) Selective Laser Trabeculoplasty
a) December 2007 Survey of Ophthalmology
b) 1-Year Combined Results
c) 59-96% Response Rate
d) 18-40% Average IOP Reduction
e) Recent data suggests similar efficacy to Latanaoprost (Xalatan)
i) Probably more like 4-6 mmHg lowering
9) Who is a Good Candidate?
a) COAG or MMG (certain cases)
b) Maximum medical therapy
c) Intolerance of medical therapy
d) On multiple drops
i) Can eliminate one or possible two meds
e) Non-compliant patients
f) Non-believers
g) Dementia / Alzheimers issues
h) Cost does matter
10) Selective Laser Trabeculoplasty
a) Easier and safer to perform than ALT
b) No damage to the meshwork
c) Effective
d) Possibly Repeatable
e) Works after ALT
f) Maximum IOP reduced at 5 weeks
g) Lotemax qid x 1 week for post op
h) Can adjust glauc gtts at 1 week pending
11) Endocyclophotocoagulation
a) Not the same as other cyclodestructive procedures for end-stage glaucoma
b) Old procedures (diatherymy or cryo)
i) Painful
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ii) Trans-scleral
iii) No direct visualization
iv) Aim to DESTROY
v) Mostly refractory glaucoma
Endoscope Details
a) Light Source - 175 watt Xenon
b) Laser Source – 810nm diode
c) Image – High resolution Toshiba camera with 110 degree field
d) Straight or Curved Fiber Optic Probe
e) Curved probe does not require additional incision for full 270 degree treatment
ECP
a) 270 degree treatment area (can do 360 or 180)
b) Phakic, pseudophakic, aphakic
c) Pars plana approach possible
d) Corneal opacity not an issue
e) Most common application is in conjunction with cataract surgery
i) Phacoemulsification as normal
ii) Place lens implant in the bag
iii) Inflate sulcus region (not the capsule)
iv) Insert endoscope through standard temporal incision to visualize ciliary processes
v) Apply laser treatment
Video of ECP procedure
ECP Candidates
a) Anyone with glaucoma on multiple medications
b) COAG
c) MMG
d) Can consider with NVG or CAC
e) Anyone with concurrent cataract
f) Pediatric glaucoma
g) Iritis is a relative contraindication
ECP Preoperative Care
a) Continue glaucoma medications
b) Add PO Diamox preop and continue 1 week
c) D/C Prostaglandin Analogs (CME risk)
d) CME prophylaxis
e) NSAID pre and postop
ECP Post-Op Regimen
a) Individualized Management
b) Steroid 6X-day initially
c) Diamox 250mg BID
d) Xibrom BID
e) Glaucoma Meds
f) Management based on severity of damage
g) Based on postoperative pressures
Postoperative ECP Care
a) Post-op pressure spikes
b) May need paracentesis ‘ burp’
c) Necessitates close monitoring (more visits)
d) Slightly increased risk of CME
e) NSAID for one month
f) Increased risk of late inflammation
g) Longer duration of Prednisolone Acetate 1%
h) May need switch to Lotemax after 3-4 weeks
ECP
a) Safe with minimal complications
b) Careful postoperative management
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c) Watch IOP closely in advanced damage cases
d) Stable long-term IOP reductions
e) Efficient in conjunction with phaco
f) Rarely used alone or in phakic patients
g) Cost effective
ECP Case Report
Filtering Surgeries
a) Indications
b) Disease progression despite all other efforts exhausted
c) IOP at episclerous venous pressure but worsening VF or cupping
d) IOP not at goal despite maximum meds or SLT
e) Poor compliance/ intolerance to drops
f) Will the patient go blind in their lifetime if surgery not performed?
Trabeculectomy
a) Most common filtering operation
b) Lowers IOP by creating a fistula between the inner eye and subconjunctival space
c) Choosing a surgical site
d) Limbus or fornix-based conjunctival flap
e) Tenon’s capsule is grasped and cut
f) Create scleral flap
g) Apply MMC, 5FU
h) Sclerectomy done using Kelly or Agarwal punch
i) Iridecotmy performed to prevent obstruction of the sclerectomy
j) Closure of scleral flap w/ sutures
k) Tightness regulates aqueous flow to bleb
l) Conjunctival closure
m) Trabeculectomy Post Op
n) Prednisolone 6-8x a day to prevent scarring and tapered over 3 months
o) Topical antibiotic qid 2 wks
p) Establish elevated bleb early on- no flat or inflamed bleb
q) Post operative goals:
r) Lower IOP
s) Prevent vision loss
t) Prevent bleb failure due to scarring
u) Minimize post surgical complications
Prevention of Bleb Failure
a) Role of antimetabolites 5-fluorouracil / mitomycin C
i) Inhibits fibroblast proliferation → subsequent scarring
ii) MMC more potent than 5FU
iii) Can be toxic to the endothelium
iv) Higher success rate but higher complication rates
v) Hypotony, bleb leaks, choroidal effusions, endophthalmitis
vi) 0.2-0.5mg/ml solution MMC or 50mg/ml 5-FU applied for 30 sec to 5 min using a cut,
cellulose sponge
vii) Applied over episclera to the site of planned scleral flap or under scleral flap
viii) Afterwards, entire area irrigated with BSS
ix) Can also use 5-FU in immediate post op and injected into subconj space
b) Digital compression of bleb
c) Digital pressure applied at inferior sclera through closed lid for 5-10 secs
d) Helps elevate bleb and reduce IOP in early post op period
e) Do several times a day
Post Operative Complications
a) Suprachoroidal Hemhorrage
b) Infection/Endophthalmitis
c) Hypotony → maculopathy →choroid effusions
i) Fluid in suprachoroid space/ detachment= choroidal effusion
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ii) Cycloplegics, steroids, autologous blood, resuture scleral flap, drain choroids
d) Shallow Chamber
e) Aqueous Misdirection
f) Bleb Leaks → endophthalmitis, hypotony
g) CME
h) Loss of BCVA
i) Bleb Failure/ Scarring
j) Higher IOP than goal
k) Argon laser suture lysis
l) Bleb Leaks→→ endopthalmitis
i) Large BCL, fibrin tissue glue, blood injection, antibiotic
m) Encapsulation/ Tenon’s Cyst
i) Occurs during 1st month post op
ii) IOP becomes elevated
iii) Treatment
iv) Diamox, aggressive steroids
v) Bleb needling
vi) Adjunct 5 FU
EX-Press Filtering Device
a) New implant designed to enhance trab surgery
b) Better control of aqueous through fistula
c) Exact trabeculectomy surgery except for sclerectomy
d) Insert shunt under scleral flap into anterior chamber via a 27 gauge needle track
i) Close flap with interrupted nylon sutures that can be laser lysed “shunt under a trab flap”
Express video
Ex-Press
a) Consistent aqueous flow through a 50-μm opening that allows for formation of a posterior,
low-diffuse bleb
b) Long-term results may be equal to those produced by trabs, but with less short-term risks
associated with trabs
c) Less hypotony, inflammation
d) Expensive and may not deliver as low of IOP but if worried about hypontony, may be worth
it
e) Can repeat surgery w/ standard shunt if ExPress fails
Tube Shunt Surgery
a) Suture plate to sclera posterior to recti muscles
b) 22 gauge needle enters eye and creates entrance track for tube
c) Tube placed through track and sutured to sclera
d) Sclera or pericardium sutured over tube from limbus to plate base
e) Patch graph laid over tube to prevent erosion
f) Tenon’s and conjunctiva closed
Implant Types
a) Non-valved (free flow)
i) Tube usually ligated with dissolvable suture in beginning until bleb forms
ii) Tube is like a straw
b) Valved (resisted flow)
i) Have flow resistant leaflets similar to cardiac valves
ii) Valve automatically close if IOP too low
c) Important because before bleb forms in post op, aqueous flows unimpeded through
implant → hypotony
Non-valved
a) Molteno- 1st aqueous shunt
b) Molteno 3 reduces postoperative hypotony by restricting aqueous drainage to small
primary drainage area until the IOP rises sufficiently to allow drainage of aqueous over the
entire plate
c) Baerveldt (350mm)
i) Increased capacity to drain aqueous and relieve pressure than smaller plates long term
31) Valved
a) Ahmed
i) Slightly lower risk of hypotony due to valve
ii) Smaller plate than baerveldt (180mm)
b) ? Long term IOP control
c) Sometimes fails to bring the IOP into the low teens needing adjunctive topical medication
d) Easier to implant than Baerveldt
32) Ahmed Baerveldt Comparison Study
a) 276 patients received either a Ahmed or Baerveldt 350mm2 implant
b) Avg. IOP reduction at one year post op
i) Ahmed = 15.4mmHg
ii) Baerveldt = 13.2mmHg
c) Failure rate at 1 year (IOP>22mm or lower than 6mm or not reduced by 20% from baseline)
i) Ahmed = 16.4%
ii) Baerveldt = 12.3%
d) If failure defined IOP > 17mm
i) Ahmed = 22%
ii) Bearveld = 16%
33) Solx Gold Shunt Tube
a) 3 x 6 mm 24K gold plate containing microtubular channels- blebless
b) Bridges AC and suprachoroidal space
c) Indicated for patients with
i) Target IOP 15 /16 mm Hg
ii) Failed Trab or Schlemm’s canal procedures
d) Not yet FDA approved but approved in Canada
e) Easy surgically- may be for general OMD
f) Some of micro-channels on plate not open and opened by a laser
g) 6 month studies show IOP at 16mm
34) Post Operative Complications Shunt Tube
a) Early post-operative hypotony, choroidal effusions
b) Failure of the shunt tube to adequately lower intraocular pressure
c) Implant extrusion, wound leaks, tube blockage, and endophthalmitis
d) Double vision (6-9%)
e) Plate placed and sutured near/under recti muscles
f) Corneal endothelial decompensation
35) Trab vs. Shunt?????
a) TVT (trab vs. tube) Study (Steve Gedde)
b) 212 randomized patients to 350-mm2 Baerveldt tube or trab with MMC
c) Already had cataract surgery and/or failed trab
d) Tube shunt more likely to maintain IOP control, avoid hypotony and reoperation than trabs
3 yrs post op
e) Both had similar IOP reduction and need of adjunct drops at 3 yrs.
f) No difference in visual loss
g) 1 in 3 had a loss of 2 lines in acuity in either group
h) Primary tube vs. trab study underway
36) Trab vs. Tube?
a) Tube better suited for
b) Aphakic, Previous Retinal or Failed Trab Surgery
c) Scleral/Collagen Vascular Disease
d) Corneal Transplant patients
e) Risk of endothelial decompensation and rejection
f) NVG or Uveitic Glaucoma
g) Pediatric Glaucoma
h) Can do tube shunt after trab but once you move to tube shunt, you can’t do a trab later
37) Filtering Surgery Summary
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a) Each surgeon will have their favorite procedure
b) Fine balancing act between too much drainaige (hypotony) and not enough (IOP not below
9mm Hg)
c) All other medical/ surgical options should be tried first due to risk of complications
Trabeculotomy- Angle Surgery
a) Remove a 60-120 degree strip of TM and inner wall of Sclemm’s canal
b) Removal done by electrocautery using a trabectome (neomedix)
c) Direct visualization with gonio lens during procedure
d) Goal is to achieve direct flow of aquesous into canal then to collector channels
Video trabectome
Angle Surgery with Trabectome
a) Post op regimen
i) Pilocarpine 1-2% BID for two week
ii) Topical antibiotic QID for one week
iii) Topical steroid QID, continued as needed depending on degree of hyphema
iv) Resume glaucoma medications
b) 40% mean decrease in IOP
c) 70% patients respond to treatment
d) Possible first line in glaucoma surgery
e) Need to visualize TM (no corneal scar, open angle)
f) IOP does not go below low-mid teens
g) Not for advanced COAG
h) Can be used for those starting with high IOPs
i) Can be combined with phaco (trabectome first)
j) Can do a trabeculectomy after
k) Before or after SLT???
l) Unclear if IOP in low teens can be achieved routinely with adjunct medical therapy
iScience Canaloplasty
a) 250 um microcatheter with fiber optic tip passed through Schlemm’s canal
b) Healon injected and this dilates canal
c) Then 10-0 prolene suture dragged through canal by catheter
d) Suture ends tied together so tension on inner wall opens canal
e) Can be primary procedure
f) Combined with phaco
g) Before trab
h) FDA approved 2008
Canaloplsty video
Canaloplasty
a) Much less intense follow up
b) Learning curve: identify the canal
c) Extent of suture tension in canal
d) Complications
e) Hyphema
f) Not as low of IOPs early on as other surgeries
g) 25% Failure rate
Other Types
a) Eyepass Implanti) Not FDA approved yet
ii) Y shaped device shunts aqueous into Schlemm’s canal
b) Eximer Laser Trabeculostomy
i) Fiberoptic probe lasers TM
ii) Creates micro perforations that connect AC to Schlemm’s canal w/o thermal damage
iii) Avail in Europe not FDA approved
c) Glaukos iStent
i) Titanium L shaped micro stent that fits in Schlemm’s canal
ii) Weighs 60ug and is 120um in diameter
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iii) 1/5000 the size of Baerveldt shunt
iv) In phase 3 clinical trials- not yet FDA approved
v) Make insertion into cornea, bypass TM
vi) Use gonio lens to view angle
vii) Insert microstent into Sclemm’s canal near lower nasal quadrant and collector channels
viii) Bypasses obstructed TM
ix) For early to moderate glaucoma
x) Can be combined with cataract surgery
i-stent video
Glaukos iStent
a) Study 240 patients
b) 73% achieved IOP <21mmHg without meds vs. 50% controls
c) Study 58 patiens
d) 62% had IOP 18mm, 26% had IOP 15mm without meds at 1 year
e) Pressures won’t fall below episcleral venous IOP (10mm HG)
Filtering Surgery vs. Angle Surgery
a) Trab is still gold standard for adv. glaucoma
b) Angle surgery will not yield IOPs <10-12
i) Cannot have multiple types of angle surgeries
ii) Can only choose one
iii) Need an open angle/ view of Schlemm’s
iv) May be more difficult to do trab after angle surgery
v) Angle surgery viable option for patients on multiple meds/high initial IOP before trab/tube
with less risks
c) Think of cardiovascular analogy
i) Angioplasty or stent used for angina, 1st heart attack (re-establish flow)
ii) Bypass surgery for when that doesn’t work or disease too advanced
Case Report
Summary
a) Laser surgery option is an alternative to meds
b) Angle Surgeries may be an option before trab/shunt tube
c) Invasive surgery only when all other options utilized
d) Procedure selection depends on type of glaucoma, previous history of failed trab or
corneal transplant, age, ability to comply, IOP goal
e) Educate patient on risks
f) Close monitoring afterwards
References
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Yaniv Barkana, MD1 , Michael Belkin, MA, MD. Selective Laser Trabeculoplasty. Survey Opthlamology: Vol. 52,
Issue 6, Pages 634-654
Maris, Peter J. G. Jr MD; Ishida, Kyoko MD; Netland, Peter A. MD, PhD. Comparison of Trabeculectomy With ExPRESS Miniature Glaucoma Device Implanted Under Scleral Flap. Journal of Glaucoma: January 2007. Volume
16 - Issue 1 - pp 14-19.
Steven D. Vold, MD; Laurie Dustin, MS; and the Trabectome Study Group
Impact of Laser Trabeculoplasty on Trabectome® Outcomes. Ophthalmic Surgery, Lasers& Imaging Vol. 41, No.
4, 2010
Speigel D, Wetzel W, Neuhann T, et al. Coexistent primary open angle glaucoma and cataract: an inteim analysis
of trabecular micro-bypass stent and concurrent cataract surgery. Eur J Opthalmol.2009;19:393-9
Gedde SJ, Schiffman JC, et al. Three-Year Follow-up of the Tube Versus Trabeculectomy Study . AJO.
2009;148:670-684 .