Trabeculectomy, trabeculotomy, goniotomy and their complications

surgical management of glaucoma- indications, procedure and complications- ophthalmology

1. Trabeculectomy , T rabeculotomy , G oniotomy and their complications DR. NAMRATA GUPTA

2. Incisional Surgery Frequently used for chronic forms of glaucoma in adults – Filtering procedure External filtration: Full thickness( S cheie ) procedures: Thermal sclerostomy , sclerectomy , Elliott’s trephination Guarded procedures: Trabeculectomy Internal filtration: Cyclodialysis Trabecular meshwork disruption: Trabeculotomy ab externo Goniotomy

3. Trabeculectomy

4. Introduction Trabeculectomy , a guarded filteration procedure remains the ‘gold standard’ for long lasting intraocular pressure reduction in uncontrolled glaucoma Popularized by Cairns (1968)

5. Mechanism of action Creation of a fistula at the limbus which allows a direct communication between anterior chamber and subconjunctival space bypassing the trabecular meshwork, schlemm canal and collecting channels

6. Theories of mechanism 1 5 4 3 2

7. Pre-operative evaluation

8. Indications Intraocular pressure too high to prevent future glaucoma damage and functional visual loss Documented progression of glaucoma damage at current level of intraocular pressure with treatment Presumed rapid rate of progression of glaucoma damage without intervention Poor compliance with medical therapy : cost , inconvenience, understanding of disease Intolerance to medical therapy due to side effects

9. Assessment of filtration risk factors Thorough slit lamp evaluation, gonioscopy , record review of past surgery Best site for filtration determined: PAS, IOL and haptic orientation, aberrant vessels, wound dehiscence, limbal scarring, vitreous prolapse Risk factors for filtration failure: African race, uveitis, aphakia , neovascular glaucoma, prior failed filtration, prolonged anti-glaucoma medication Ocular surface disease: ocular rosacea, blepheritis

10. Surgical Technique Perioperative preparations: Intravenous sedation : pediatric, adults unable to co-operate Local anesthesia: Retro-bulbar injection, peribulbar injection, subtenon , subconjunctival or topical anesthesia Positioning to maximize exposure to superior globe: protection by lid, no diplopia after PI

11. Traction sutures Superior rectus traction (or bridle) suture Complications: subconjunctival hemorrhage, conjunctival defects, scleral perforation postoperative ptosis

12. Traction sutures Clear Corneal traction sutures : A 7-0 polyglactin ( vicryl ) suture is passed through approx. ¾ th thickness of superior peripheral cornea(4-5 mm width) 1mm form limbus May distort the cornea and anterior chamber during surgery

13. Conjunctival flap General principles: Gentle handling- buttonholing ( antifibrotics ) Removal of portion of Tenon capsule : source of fibroblast (controversial)

14. Conjunctival flap Two types of conjunctival flap: Limbal based conjunctiva flap (LBCF) – incision deep in fornix with base at limbus Fornix based conjunctival flap (FBCF) – incision at limbus with base at fornix

15. Limbal based versus fornix based flap

16. Anti-metabolite decision Adjunctive antimetabolites inhibit the natural healing response that may preclude successful filtration surgery Stratified according to patient risk factors

17. 5-Fluorouracil Pyrimidine analogue antimetabolite Inhibition of thymidylate synthesis, blocks DNA synthesis Inhibit fibroblastic proliferation Concentration: Cellulose sponge soaked in 50mg/ml for 5 mins

18. Mitomycin C More potent than 5-FU Antineoplastic antibiotic isolated from Streptomyces caespitosus Selectively inhibits DNA replication, mitosis and protein synthesis-inhibits proliferation of fibroblast, suppresses vascular ingrowth Concentration: 0.2-0.5 mg/ml for 1-5 mins depending on magnitude of risk factors

19. Delivering the anti-fibrotic agent Cellulose sponge ̴ 5 × 3 mm soaked in antimetabolite is placed under dissected tenon’s capsule for 5 mins before paracentesis of AC followed by thorough irrigation with BSS

20. Ring of steel Cover largest area possible for more diffuse noncystic bleb and prevent posterior limiting scar (‘ring of steel ’)

21. Moorfields Eye Hospital (More Flow) intra-operative Single Dose Anti- Scarring Regimen 2006 Low Risk Patients (Nothing or intra-operative 5-FU 50mg/ml) No risk factors Topical medications (beta-blockers/ pilocarpine ) Afro- Caribean Youth <40 with no other risk factors

22. Intermediate risk patients (intraoperative 5-FU 50mg/ml or MMC 0.2 mg/ml) Topical medications (adrenaline) Previous cataract surgery without conjunctival incision Combined glaucoma filtration surgery/cataract extraction Previous conjunctival surgery eg . Squint surgery/ detachment surgery/ trabeculotomy More flow contd.

23. High risk patients (Intra operative MMC 0.5 mg/ml) Neovascular glaucoma Chronic persistent Uveitis Previous failed trabeculectomy /tubes Chronic conjunctival inflammation Secondary glaucomas : inflammatory, post-traumatic angle recession, iridocorneal endothelial syndrome Aphakic glaucoma More flow contd.

24. Complication of antimetabolites Corneal epithelial defects Post-operative wound leaks Cystic thin walled bleb: C hronic hypotony , late-onset bleb leak, endophthalmitis

25. Scleral flap dissection Provide resistance to aqueous outflow and prevent hypotony Act as a safety valve to minimize IOP fluctuations Technique: Rectangular(3.5 x 4.5 mm) or triangular partial thickness ( ̴ 50%) Lamellar dissection anteriorly just into clear cornea

26. Difficulties T hin scleral flaps– reduced flap resistence and hypotony Flap dehiscence, full thinkness button holes, cheese wiring Important in eyes with low scleral rigidity: buphthalmos , myopia, antifibrotic use

27. Paracentesis An oblique paracentesis in inferior cornea allows fine control of the AC: IOP titration after tying the scleral flap sutures Reformation (or decompression ) of AC intra or post operatively- BSS or viscoelastics Infusion for continuous IOP maintainence in high risk Control and washout of AC hemorrhage

28. Sclerostomy Anterior corneoscleral entry into AC- reduces risk of iris incarceration and bleeding from iris root and ciliary body Punch sclerostomy - Khaw / Kelly descement membrane p unch Manual block removal clean 0.75mm round hole without tissue tags

29. Peripheral iridectomy Routine part of all standard filtering procedures Performed from sclerostomy site with extent beyond sclerostomy margins to avoid obstruction of sclerostomy by peripheral iris Complications: Hyphaema , inflammations, iridodialysis

30. Closure of the wound Approximation of scleral flap with nylon 10-0 that achieves mild to moderate resistance to aqueous flow maintaining AC depth is optimal Adequate flow resistance can be tested by injecting BSS into AC via paracentesis

31. Scleral flap sutures- Fixed, R eleasable , Adjustable

32. Fixed sutures and laser suture lysis Laser suture lysis introduced by Lieberman (1983) using argon laser Facilitated by compressing overlying conjunctiva to visualize scleral suture or high magnification suture lysis contact lens (Hoskins or Blumenthal lens) Argon laser: 50µm, 0.1 sec duration, 250-1000 mW power Within first 3 weeks: enhance filtration before scarring occurs Delayed ( upto 8 weeks) if intraoperative antimetabolite used

33. Laser suture lysis

34. Releasable sutures Preferred: Scleral flap sutures obscured by subconjunctival hemorrhage, thickened tenon’s capsule or fibrosis First originated from Shaffer et al (1971) Simple, low-cost and efficacious

35. Adjustable sutures Allows trans- conjunctival adjustment of tension post-operatively for gradual titration of IOP using specially designed forcep with blunt tip Khaw adjustable suture forcep

36. Adjustable suture forcep

37. Post-operative management Medications: Topical steroids: early restoration of blood aqueous barrier and suppression of wound healing Prednisolone acetate (1%) 2 hourly for 2 weeks and tapered over 8 weeks Topical antibiotics: 4 weeks post operatively Topical mydriatic / cycloplegic agent : Atropine 1% prevents AC shallowing and risk of malignant glaucoma Oral or IV steroids: not routinely used , in severe uveitic glaucoma

38. Scleral flap suture manipulation Removal of one or more releasable scleral flap sutures Laser suture lysis A djustable suture loosening Incorrect timing may result in hypotony or permanent subconjunctival fibrosis and GFS failure

39. Adjuvant subconjunctival 5-Fluorouracil Inhibits fibrosis in T enon’s layer After first postoperative week for up to several months to modulate wound healing (useful in presence of subtenon lake) 5mg (0.1 ml of 50mg/ml) 5-FU deep in superior fornix of 90° from the bleb

40. Adjuvant subconjunctival 5-Fluorouracil Signs of impending bleb failure Increased bleb vascularity Thickening of conjunctiva and tenon’s capsule Reduction in bleb size and height Reduction of conjunctival microcyst Progressive elevation of IOP

41. Bleb N eedling R evision Failure of previous methods Puncturing and loosening the scar tissue of filtration bleb to increase sub- tenon’s aqueous lake Two types of BNR: Sub- Tenon’s Needling Subscleral flap Needling

42. Subtenon’s needling

43. Subscleral Flap Needling Early post operative subscleral flap needling if sub tenon’s Needling fails

44. Complications Intra-operative complications Conjunctival tear Hemorrhage Scleral flap damage Supra- choroidal Hemorrhage Decompression Retinopathy

45. Intra operative Complications Tearing or buttonholing of cinjunctival flap: Prevention : M inimal handling Topical adrenaline to reduce vascularity and bleeding Stromal hydration- BSS injected under cinunctiva / tenon to make them thicker Blunt dissection

46. Tearing or buttonholing of conjunctival flap Management: Small holes- Tissue adhesives, light bipolar cautery Figure of 8 or mattress suture Large holes- Purse string vicryl suture

47. Hemorrhage: Should be minimized as blood is potent stimulus for fibrosis Risk factors: Long term anti-glaucoma medication Aspirin, anti-coagulants Management: Wet field diathermy Gentle sustained pressure over fistula Large air bubble or viscoelastic in AC

48. Scleral flap damage: tearing and buttonholing Avoid thin flap and excessive manipulation Management: Minor damage- repair Severe damage- autologous or donor sclera patch

49. Suprachoroidal hemorrhage: Sudden reduction in IOP with rupture of a large choroidal vessel Risk factors: High pre-operative pressure Generalized atherosclerosis Elevated intraoperative pulse Young patient Large eyes, nanophthalmos Sturge –weber syndrome Management: All wounds closed rapidly Peripheral SCH: conservative Extensive SCH- rainage

50. Decompression retinopathy Retinal hemorrhage following rapid IOP reduction Vitreous loss Inadvertent damage to lens/ zonule complex during PI Prevention: Anterior sclerostomy Avoid basal PI’s Tube surgery in iridolenticluar instability

51. Post operative complications Early post-operative complications: Hypotony and shallow anterior chamber Hypotony and deep anterior chamber Elevated intraocular pressure and flat anterior chamber Elevated intraocular pressure and deep anterior chamber

52. Spaeth classification of post operative shallow anterior chamber: Grade 1: peripheral iris- cornea apposition but preserved AC in front of pupillary space Grade 2: Greater apposition between mid iris and cornea but space between lens(or vitreous) and cornea in pupillary space is retained Grade 3: Flat AC with complete contact of iris and pupillary space with posterior surface of cornea

53. Hypotony with flat anterior chamber : Negative seidel test with grade I or II flat AC with hypotony with a formed bleb- Scleral flap leak Management: Conservative : Topical steroids and long acting cycloplegic Restricted activity and avoid Valsalva Pressure patch of filtration site

54. Pressure patch technique

55. Hypotony with flat anterior chamber : Positive Seidel test with grade I flat anterior chamber and low intraocular pressure- small leaks around sutures Increased frequency of topical antibiotics Pressure patching Therapeutic contact lens- Fibrin tissue glue or cyanoacrylate glue Simmon shell

56. Positive seidel’s test with low bleb height with grade II or III flat AC with hypotony : Conjunctival button hole Management: Conjunctival tear: Healthy conjunctiva: Purse string suture Fragile conjunctiva: Pressure patching, 20-22 mm BCL, Tenon capsule sutured a tear site AC reformation: Air, BSS, viscoelastics

57. Hypotony with flat anterior chamber : Excessive filtration: Loose scleral flap closure or large filtering bleb (anti-fibrotic) Large soft contact lens Symblepheron ring Simmons shell Surgical: Viscoelastics , BSS, 15% perfluoropropane (C3F8), 40% sulfur hexa fluoride(SF6) Symblepheron ring

58. Hypotony with flat anterior chamber : Serous choroidal detachment Mechanism: Pressure differential in hyotonic eyes causes fluid with small and medium sized proteins to diffuse from choroidal capillaries to extravascular space Prolongs hypotony by reduced aqueous production and increased uveoscleral outflow

59. Management: Resolve spontaneously after IOP rises above 7-9 mmHg: Atropine and oral and topical steroids Surgery : Persistence of grade 3 flat AC more than 1 week with corneal endothelial compromise or persistence of ‘kissing choroidals ’ or suspected SCH: O ne or more sclerotomies 4mmbehind the limbus over pars plana in inferior quadrants and deepening AC with BSS

60. Hypotony with deep anterior chamber: A lower-than-normal IOP in first 2 weeks with no associated complication resolve spontaneously Persistent hypotony (<6mmg): H ypotony Maculopathy Fine macular striae radiating from fovea Extensive choroidal folds Tortuous retinal vessels Disc edema No evidence of vascular leak

61. Risk factors : Young age, male gender, myopia, preoperative CAI, antimetabolites, iridocyclitis , cyclodialysis , ciliochoroidal detachment Management : Pressure patching Large BCL Autologous blood injected into bleb Surgical: C onjunctival compression sutures, resuturing of scleral flap, patch graft with donor sclera Return of good vision seen with reversal of over-filtration within 6 months of onset

62. Elevated IOP with flat anterior chamber Aqueous misdirection syndrome(malignant glaucoma) Delayed suprachoroidal hemorrhage An incomplete iridectomy with pupillary block glaucoma- P atentcy should be established immediately on diagnosis by laser or, if necessary, incisional surgery

63. Aqueous misdirection( ciliary block /malignant glaucoma) Misidrection of aqueous to circulate into vitreous Grade II or III shallow AC Higher than expected IOP in early post-operative period Patent iridotomy Rarity of spontaneous resolution- ‘malignant’

64. Malignant glaucoma Management: Atropine and topical steroids Aqueous suppressants: Brimonidine , T imolol , CAI’s, IV mannitol Surgical intervention: waiting period of 5 days advised Nd-Yag laser- pupillary block, retrocapsular block or hyaloid block Pars plana vitreous aspiration or Pars plana vitrectomy Cyclodiode photocoagulation (refractory cases)

65. Suprachoroidal hemorrhage Risk factors: Aphakic Post-traumatic Vitrectomised eyes Large eyes- Pathological myopia/Congenital glaucoma Systemic anticoagulants Significant post-operative hypotony

66. Suprachoroidal hemorrhage Sudden severe pain with loss of vision during first 4-5 post-operative days High IOP with nausea and vomiting Management: Aqueous suppressants/ hyperosmotic agents Surgical drainage: P osterior sclerostomy over area of elevated choroid after 7-10 days with simultaneous AC infusion Poor prognosis with concomitant RD or 360° SCH

67. Elevated IOP with deep anterior chamber: Indicates inadequate filtration Tight scleral flap Obstruction of fistula by iris, ciliary process, lens, blood or vitreous Management: Tight flap: Laser suture lysis Obstruction of fistula: Retraction of obstructing tissue with argon laser of Nd-Yag disruption under gonioscopy Pressure on posterior lip: clot or vitreous at sclerostomy site Internal bleb revision: C yclodialysis spatula inserted 90-180° away through clear corneal incision into the fistula to elevate scleral flap

68. Failing bleb Characteristics: Typically low-flat Heavily vascularized No microcysts Management: Increased frequency of topical steroid ± subconjunctival steroid/5-FU Intermittent digital pressure Laser suture lysis / removal of adjustable suture Failure of above: Anti-glaucoma resumed and revision of surgery

69. Bleb manipulation techniques Bleb massage Digital pressure through upper lid as posterior as possible to scleral flap under direct slit lamp visualization Steady pressure with index finger to inferior sclera through lower lid for 15 seconds Repeated several times over first few weeks

70. Encapsulated filtering bleb In 3.6% - 28% within first 2 months after surgery Tenon capsule cysts: Highly elevated, smooth doomed bleb with intervening avascular spaces and no microcysts Patent sclerostomy on gonioscopy Management: Resume anti-glaucoma medication until improvement occurs Subconjunctival needling with 5mg of 5-FU subconjunctivally

71. Other early post-operative complications Uveitis Hyphaema Dellen : Adjacent to large filtering bleb Loss of central vision: “Snuff-out syndrome”- common in old age, hypotony , macular splitting(visual field loss within 10° of fixation)

72. Late post operative complication Late failure of filtration : Fibrosis of scleral flap Scarring of conjunctiva Poor response to drugs or digital pressure Management: Ab externo or ab interno incision of membranous tissue over fistula Argon laser for pigmented membrane Nd-Yag laser for non pigmented membrane Incisional surgery

73. Late post operative complication Leaking filtering bleb Thin walled large avascular blebs are at risk Use of adjunctive anti-metabolite Management: Cyanoacrylate glue, autologous fibrin, large BCL Bleb revision: New conjuntival flap or rotational conunctival flap

74. Bleb related infections Blebitis and endophthalmitis are potentially blinding emergencies Tends to occur months or years after surgery Prevention of late infection Avoid excessive antifibrotic treatment Avoid thin scleral flaps Bleb under upper lid

75. Blebitis White bleb with surrounding intense conjunctival injection Variable anterior chamber reaction Clear vitreous Risk factors: Early chronic intermittent bleb leak Myopia: thin scleral flap Intra-operative MMC Blepheritis Diabetes mellitus Chronic antibiotic use Treatment: T opical antibiotics

76. Bleb-related E ndopthalmitis Early postoperative E ndophthalmitis : Onset within first 3 months Staphylococcus epidermidis Delayed- onset E ndophthalmitis Onset after 3 months Streptococcus, staphylococcus, H. influenzae

77. Bleb-related Endopthalmitis Milky white appearance of bleb, fibrin or hypopyon in AC and vitritis (distinguishes from blebitis ) Management: Aqueous and vitreous aspirates High dose parenteral and periocular antibiotics Intravitreal antibiotics Poor visual prognosis

78. Other late post operative complications Development and progression of cataracts Spontaneous hyphaema Hypotony and ciliochoroidal detachment: inflammation, aqueous suppressants Rare: U pperlid retraction, sympathetic ophthalmia

79. Goniotomy and T rabeculotomy

80. Definition Goniosurgery First introduced by Barkan (1938 ) Specific surgical techniques applied to the anterior segment of the eye for the treatment of childhood glaucoma Principle: Incision of the obstructing trabecular meshwork tissue allows direct conduit between anterior chamber and schlemm’s canal

81. Goniotomy Indications: Primary congenital infantile open angle glaucoma(3- 12 months) Other primary glaucomas Juvenile open angle glaucoma Axenfled R ieger syndrome, L owe syndrome Neurofibromatosis, S turge weber syndrome Selected secondary glaucoma Open angle glaucoma after congenital cataract surgery Glaucoma with chronic anterior uveitis

82. Goniotomy is advisable as soon as possible after diagnosis as early as second or third day of life in glaucoma present at birth It is recommended once or twice in children younger than 2-3 years Shaffer reported that one to two goniotomies cured 94% of cases between 1 and 24 months Advantages: Does not disturb conjunctiva, direct visualization of trabecular meshwork

83. Goniotomy Preoperative care: Preoperative glaucoma medications to reduce IOP and clear cornea Beta-blockers (0.25%), Oral acetazolamide (10-15 mg/day) or topical dorzolamide with apraclonidine 0.5% Pilocarpine 1-2% just before surgery to promote miosis Rule out congenital NLD block or URTI Isopropyl alcohol 7-% to remove corneal epithelium if edema persists( intraoperatively )

84. Procedure: Eye positioned with plane of iris tilted away from surgeon at 45° Locking fixation forceps on vertical recti, if nasal or temporal goniotomy is to be performed Operating microscope tilted towards the surgeon for comfortable view of angle through goniolens

85. Swan goniotomy knife Swan Jacob goniolens

86. Complications: Risk of general anesthesia in neonates and infants Hemorrhage: Incision into anterior ciliary body, sclera Cataract: lens injury I nfection Epithelial ingrowth Failure: Incision anterior to schwalbe line

87. Post-operative care: Patient’s head turned towards side of puncture wound for first hour that facilitates blood from goniotomy incision to flow away Routine F/U: Infection, cornea, AC, IOP EUA after 4-6 weeks Reoperation may be performed after 3 weeks Trabeculotomy : If two goniotomies fail

88. Trabeculotomy Performed by cannulating the schlemm canal from an external approach with subsequent centripetal rupture through the trabecular meshwork into the anterior chamber Indications: Same as that of goniotomy in presence of corneal edema or opacification After failure of two previous goniotomies Combined with trabeculectomy (failure to cannulate schlemm canal)

89. Harms trabeculotome McPherson probe

90. Procedure Thick scleral flap created(deeper than trabeculectomy ) Radial incision made in bed of flap at s clero -corneal junction and deepened until schlemm canal identified anterior to scleral spur(near posterior limbal gray zone) A 6-0 blunt tip prolene is threaded on either side of radial incision to confirm patency Internal arm of trabeculotome passed gently into canal and rotated into AC through intervening TM

91. Purse- string 360° Trabeculotomy After unroofing and identifying schlemm’s canal, a 6-0 prolene suture is threaded 360°around After reappearing form the opposite direction at initial surgical site, suture is drawn like a purse string rupturing the entire canal in centripetal fashion

92. Complications Intra or Post operative hyphaema Descement’s detachment Iridodialysis Iris prolapse

93. Summary Trabeculectomy is a surgical procedure featuring a partial thickness scleral flap that creates fistula between anterior chamber and subconjunctival space for filtration of aqueous fluid and formation of bleb ± antimetabolites Gold standard for glaucoma surgery Associated features- Hypotony , choroidal detachment, bleb leak and bleb associated endophthalmitis Goniotomy and trabeculotomy are specific surgical techniques applied to anterior segment for treatment of childhood glaucoma

94. Bibliography R.Rand Allingham . Shields Text Book of Glaucoma, 6 th edition , 2011 Robert L Stamper, Marc F Lieberman, Michael V Drake. Becker- Shaffer’s Diagnosis & Therapy of the Glaucomas , 8 th edition, 2010. Daniel M Albert, Joan W Miller, Dimitri T Azar . Albert & Jakobiec’s Principle and Practice of Ophthalmology, 3 rd edition, 2008. American Academy of Ophthalmology. The Glaucoma, Section -7, 2011-12. Myron Yanoff and Jay S. Duker – Ophthalmology, 3 rd edition, 2009.

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