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.

Tissue Complications During EK:Purpose, Method

• Purpose: To report six cases of inseparable corneal lamellae during preparation of tissue for Descemet’s 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.

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.

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.

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 recipient’s 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.

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.

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.

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

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

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

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

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.