"Two-Flaps" Technique- safe, reproducible, and consistent means for Descemet Stripping: Study
Fuchs endothelial dystrophy (FED) remains the most common indication for corneal transplantation in the United States. Surgical management of FED has undergone multiple iterations over the recent decades from initially performing penetrating keratoplasties to its current state of endothelial keratoplasty, which includes Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty. The evolution of surgical management of FED has now continued to progress to Descemet stripping only (DSO) in appropriate cases. DSO has gained popularity after observations of endothelial "rejuvenation" in FED despite complete Descemet membrane endothelial keratoplasty graft detachment. The proposed mechanism for this phenomenon was thought to be either migration and regeneration of the host endothelium or transfer from the donor endothelium free-floating graft.
There are a number of critical steps in the DSO surgical technique that must be implemented to optimize surgical success. These include optimal Descemet stripping centration, size of descemetorhexis, and achieving a smooth curvilinear descemetorhexis edge. Depending on the techniques, current success rates for DSO range between 63% and 100%. Currently, there is no step-by-step description of a safe and reproducible technique for the removal of Descemet membrane in the literature during DSO. Authors describe their current technique, the "two-flaps" technique, which they felt allowed for accurate, consistent, and minimally disruptive peeling of Descemet membrane.
An ink-marked caliper set at 4.0 mm was applied to the dry surface of the cornea with 8 points applied centrally over the nondilated pupil. The "two-flaps" technique uses the Gorovoy DSO forceps. The technique takes advantage of the flat and smooth surface of the forceps to create the desired 4-mm Descemet stripping with minimal stromal trauma along with a continuous curvilinear descemetorhexis, minimizing the risk of postoperative stromal scarring and extension of the rhexis beyond 4 mm. Holding the Gorovoy forceps closed and taking advantage of its wide and flat surface area, a small nick in Descemet membrane was made using the friction of the metal against Descemet membrane. This nick creation was first performed in an anticlockwise fashion and once formed, the Gorovoy forceps was then opened and grasped to encourage further guided peeling along the preplaced marking points, creating a 2 clock hours flap. With the opening of Descemet already created, the Gorovoy forceps are then used to peel in a clockwise manner for another 2 clock hours with the newly formed 4 clock hour Descemet crescent-shaped flap opening, Descemet was grasped in the middle of this opening and peeled toward the center of the 4-mm circumference up to the halfway point. The Gorovoy forceps was then used to perform a continuous curvilinear descemetorhexis, keeping within the 8-point marker. Once this was completed, the Descemet tissue was removed from the eye through the main wound. A well-centered descemetorhexis on visual axis was performed.
This technique has been used successfully in 11 cases performed by 1 surgeon or directly supervised by him. All cases achieved the desired 4-mm circumference without any residual tags or visually significant stromal scarring, with successful clearing of the central cornea and endothelial cells repopulating the central stripped area.
Peeling of Descemet membrane rather than scoring with inadvertent excessive pressure into the deeper stroma is important for surgical success. It has been observed that avpostoperative deep stromal scar usually corresponds to the location of where the scoring has taken place. The theory, therefore, is that the surgical trauma induced by the reverse Sinskey hook to score the endothelium/Descemet membrane complex initiates an inflammatory proscarring response, leading to stromal keratocyte activation, proliferation, fibrosis, and deep Stromal scarring.
The technique described reduces the complications associated with the use of a reverse Sinskey Hook. Using the smooth, nonsharp surface of the Gorovoy forceps for creating the first nick in Descemet membrane which then extends, by peeling only, to 2 flaps of 2 clock hours for each side reduces trauma to the underlying stroma and thereby reduces the risks of stromal scarring and stromal trench formation. This technique described provides a consistent, reproducible, and relatively trauma-free peeling of Descemet membrane and associated endothelial cells/guttae to optimize the success of DSO.
This "two-flaps" technique provides a broad edge of Descemet membrane to grip with initial 4 clock hours opening in Descemet membrane, which enhances peeling of a single continuous curvilinear sheet in a more controlled and accurate manner to the desired diameter size. Akin to a capsulorhexis, the surgeon has better control to manipulate the Descemet tear at the appropriate angle to ensure no tags or Descemet membrane remnants are left behind.
In conclusions, the "two-flap" technique described provides a safe, reproducible, and consistent means of performing a 4-mm descemetorhexis, which limits the trauma and possible subsequent scarring thus optimizing the success of DSO.
Source: Cohen, Eyal; Din, Nizar; Mimouni, Michael MD; Trinh, Tanya MD et al;