Bleb leak characteristics and success of repair following trabeculectomy with Mitomycin C

1
Bleb leak characteristics and success of repair
following trabeculectomy with Mitomycin C

• Amy Hennessy, MD MPH
• Harold Bernstein, MD
• Medical College of Virginia
• Richmond, VA
• Authors have no financial interests to disclose

2
Background

• Mitomycin C and 5-fluorouracil are the most
  common adjunctive agents used in filtering
  surgery today
• Blebs may be thinner with more irregular
  epithelium, breaks in basement membrane, fewer
  goblet cells, and atrophic and avascular stroma
  1,2,3,4,5
• Thin, avascular, leaking blebs commonly
  associated with blebitis or endophthalmitis
  1,2,3,4

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Bleb leaks are relatively common and can be
potentially serious

• 4.2-10 incidence of late bleb leak after
  trabeculectomy with MMC 5
• Risk of bleb leak, blebitis or endophthalmitis
  during the first 5 years after trabeculectomy is
  4.4 per year 1
• 3 times greater incidence of bleb leak in eyes
  treated with MMC compared with eyes treated with
  5-FU (5.9 vs 1.7) 5
• In a group of 123 eyes of POAG patients followed
  for 6.8 years after trabeculectomy, 9 with bleb
  leak, 4 with blebitis 6
• In 258 trabeculectomies DeBry and colleagues
  identified 9 incidence of bleb leak 2
  blebitis, 3 endophthalmitis 1
• Infection 25 times greater in eyes with bleb
  leaks compared to those without leak 7

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Bleb leak management

• Goal
• Eliminate leak and hypotony while
• preserving filtration function and
  maintaining target
• IOP 2,7,8
• Surgical bleb leak management
• Conjunctival advancement with or without excision
  of the existing bleb, free conjunctival graft,
  scleral patch graft, amniotic membrane graft
  2,3,4,7,9
• 2 most frequent techniques free conjunctival
  graft and advancement of adjacent conjunctiva
  4,7,9
• Best surgical approach unclear 2

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Purpose of Study

• Characterize a population of patients who
  experience bleb leaks following trabeculectomy
  with mitomycin C
• Determine predictors of successful outcome of
  surgical repair by 1 surgeon
• Determine outcomes (visual acuity, IOP, Seidel
  status) before and after typical conjunctival
  advancement repair of bleb leak

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Methods

• Retrospective medical record review of 16
  patients with documented bleb leaks found over a
  3 year period
• At least 1 month of post-operative follow-up
• 2 with associated blebitis
• SAS statistical program used to analyze data
• Initial conservative treatment (aqueous
  suppression, bandage contact lens, topical
  antibiotic, eye shield) followed by surgical
  repair 2 possibilities
• If mobile conjunctiva and bleb not extending onto
  cornea, then
• conjunctival advancement with cautery to
  de-epithelialize thin conjunctiva (10/16)
• If need for bleb excision or patch graft
  required, more difficult repair performed,
  sometimes including entry into anterior chamber
  (6/16)

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Definition of successful repair

• No blebitis, no endophthalmitis, no bleb
  dysesthesia
• Resolution of leak
• No further surgery
• lt 1 additional IOP-lowering med
• IOP maintained between 6 and 21
• Grading success
• Complete success
• All criteria met no surgery or medical problems
  post-op
• Partial success
• No return to surgery, no infection, no
  dysesthesia but additional meds required to
  maintain IOP between 6 and 21
• Failure
• Return to surgery
• Need for 2 or more medications for IOP control

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Results

• 16 patients with bleb leak
• 9 male (56.25), 9 white (56.25)
• Average age at initial surgery 66.6 (9) years
• 15 POAG, 1 unintentional filtering bleb (ICCE)
• 14 trab, 1 combined procedure
• All 15 received MMC with initial trabeculectomy
• Mean concentration 0.5mg/cc
• Mean duration 1.8 minutes
• 68.75 limbal-based flap, 3 unknown, 1
  fornix-based
• Average age at leak 74.3 (7.9) years
• Mean of 95.4 months (8 years) from initial
  surgery to leak
• Surgical repair 6.1 months after leak noted
• Range 21 days-21 months
• Given 2-3 office visits with non-surgical
  measures
• Large range of delayed repair due to patient
  issues
• Refused surgery, not medically stable

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Results

• Mean follow-up after repair 8.1 months /- 4.7
  (range 1 month to gt12 months)
• Intraocular pressure significantly increased
  (plt0.0001)
• Pre-op IOP 5.3 4.1 (range 0-15)
• Post-op IOP 12.6 3.4 (range 6-21)
• Visual acuity improved (p0.09)
• Mean pre-op logMAR 0.56 (VA 20/70)
• Mean final post-op logMAR 0.33 (VA 20/40)

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Success of repair

• Complete success
• 11/16 (68.75)
• At least Partial success
• 14/16 (87.5)
• Failure 2/16 (12.5)
• IOP 27 on 4 medications
• Persistent leak
• No clinical factors predicted success or failure
• 5-FU not given in post-op period may be
  associated with failure (OR 4.8, CI 0.4-58.0)
  (p0.21)

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Conclusions

• Bleb leak is an infrequent yet significant
  problem complicating filtering surgery
• This small study on bleb leak repair shows
  similar results to studies by Catoira 2 and
  Tannenbaum 8
• Bleb repair by conjunctival advancement appears
  successful in correcting bleb leak, maintaining
  IOP, improving visual acuity and preventing
  bleb-related infection when other methods have
  failed
• It may be that 5-FU given in post-operative
  period affects the outcome of bleb leak repair

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References

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  advancement with bleb preservation. Am J
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• 3. Wadhwani RA, Bellows AR, Hutchinson BT.
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