Tissue Complications During Endothelial Keratoplasty

1
Tissue Complications During Endothelial
Keratoplasty

• David B. Glasser, M.D.
• Columbia, MD

The author has no financial interest in the
subject matter of this poster.
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Tissue Complications During EKPurpose, Method

• Purpose To report six cases of inseparable
  corneal lamellae during preparation of tissue
  for Descemets stripping automated endothelial
  keratoplasty (DSAEK).
• Method Collection of clinical case reports from
  an e-mail survey of Cornea Society and
  endothelial keratoplasty discussion group
  participants and Eye Bank Association of America
  member eye banks.

3
Tissue Complications During EK Results

• Five cases involved eye bank pre-cut tissue.
  Surgery was aborted in four of these cases. In
  the fifth, a free anterior cap was identified and
  the posterior lamella was successfully
  transplanted.
• In the sixth case, an incomplete lamellar cut was
  made in the operating room. Surgery was
  continued after manual completion of the lamellar
  dissection.

4
Tissue Complications During EK Conclusions

• The most likely causes of inability to separate
  the lamellae after punching a DSAEK donor are
• A decentered or incomplete lamellar cut, and
• Unsuspected premature separation of the lamellae
  
• Detached anterior cap prior to central
  trephination, or
• Posterior lamella inadvertently removed from the
  field after central trephination.
• Careful inspection under the microscope can
  reduce the risk of a decentered cut and identify
  the presence of both lamellae.
• DSAEK may be completed successfully with an
  intact posterior lamella.

5
Case Reports

• Case 1 After punching the central button of a
  pre-cut donor, a plane for separating the
  lamellae could not be found. A search for a free
  anterior cap on or off the sterile field or in
  the transport vial was unsuccessful. The central
  button appeared much thicker than usual. A
  smaller central punch did not produce two central
  lamellae. It was unclear if any lamellar cut had
  been made. The case was aborted. A review of
  the eye bank records revealed no deviation from
  the standard pre-cutting protocol.
• Case 2 After punching the central button of a
  pre-cut donor, the tissue appeared thinner than
  usual. The recipients endothelium was stripped,
  and when attention was returned to the donor
  button it was impossible to find a plane to
  separate the corneal lamellae. A search for a
  free cap was unsuccessful. The case was aborted.

6
Case Reports

• Case 3 After punching the central button of a
  pre-cut donor, the tissue could not be separated.
  The posterior lamella was detected adherent to
  the internal wall of the trephine. It was gently
  rinsed from the trephine with balanced salt
  solution, but the surgeon was not certain if
  irreparable endothelial damage had occurred, and
  the case was aborted.
• Case 4 After punching the central button of a
  pre-cut donor, the tissue appeared thinner than
  usual. Attempts to separate the lamellae were
  unsuccessful. A search revealed a free cap,
  presumed to be the anterior lamella, in the
  tissue transport vial. The case was completed
  with the posterior lamella, and the patient
  experienced an uneventful postoperative course.

7
Case Reports

• Case 5 An eye bank reported the return of a
  pre-cut donor due to an eccentric lamellar cut
  noted by the surgeon intraoperatively. The case
  was aborted prior to punching the central donor.
  A review of eye banking procedures resulted in a
  revision of their protocols to reduce the risk of
  similar future occurrences.
• Case 6 After making the microkeratome pass in
  the operating room, the surgeon was unable to
  identify a free anterior lamellar cap and
  presumed it was lost. The central button was
  trephined. During the attempt to fold the
  tissue, a partial lamellar cut was noted. A
  manual dissection was completed with the
  assistant providing counter traction. The
  surgery was completed successfully but a small
  area of non-attachment was noted in the immediate
  postoperative period.

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Summary of Cases
Case Lamellar Cut Donor Punch Lamella Found? Outcome
1 Eye bank, centered Central No Aborted
2 Eye bank, centered Central No Aborted
3 Eye bank, centered Central Yes Aborted
4 Eye bank, centered Central Yes Completed
5 Eye bank, eccentric NA, tissue returned NA Aborted
6 Surgeon, centered Eccentric Yes Completed
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Causes of Inseparable Lamellae After Central
Trephination

• No lamellar cut in tissue shipped by eye bank
• Anterior cap separated prior to central punch
• In eye bank, in transit, or in operating room
• Check tissue vial, area around operative field
• Posterior lamella inadvertently removed from
  field after central punch
• Check trephine barrel
• Trephine punch intersects lamellar cut
• Small diameter or incomplete lamellar cut
• Eccentric trephination

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Avoiding Complications

• Inspect donor under operating microscope to
  confirm presence and diameter of lamellar cut
  prior to central punch
• Mark edges of gutter to aid in centering trephine
• Manual extension of lamellar cut into periphery
  reduces risk of eccentric trephination
• Perform central punch and confirm presence of
  complete lamellae prior to stripping host
  endothelium

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Managing Complications

• Search for free anterior cap
• Transport vial, operative field
• Inspect barrel of trephine for posterior lamella
  after central punch
• Hand dissection if incomplete lamellar cut noted
• Easier, less traumatic if prior to central punch
• Artificial anterior chamber facilitates
  dissection
• Cases can be completed successfully with an
  intact posterior lamella
• Trypan blue can confirm integrity of endothelium

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Conclusions

• Case cancellation due to unusable tissue is
  detrimental to the patient, the surgeon, the
  operating room, the eye bank and the overall
  supply of tissue for the general public.
• Cancellations can be minimized by following the
  above recommendations.
• Communication with the eye bank about donor
  tissue problems is a critical driver for
  improvement in eye banking techniques.