Descemet's Stripping Without Endothelial Keratoplasty

Daniel Garcerant; Nino Hirnschall; Nicholas Toalster; Meidong Zhu; Li Wen; Gregory Moloney

Disclosures

Curr Opin Ophthalmol. 2019;30(4):275-285. 

In This Article

Surgical Factors

We have observed that posterior stromal scarring is often present in slow or nonresponders at the site of recalcitrant edema during the clearing process. Analysis of surgical video demonstrated that this scarring was associated with stromal scoring in every case (Figure 1). At times this stromal response assumes characteristic patterns, with our initial publications describing the formation of posterior stromal nodules at the stripped margin. The nodules observed may represent new collagen laid down in a scarring response, or epithelial mesenchymal transformation of healing endothelial cells, locally acted upon by cell signals from injured stroma. Fortunately, these are seen to fade over time, but are still detectable at 4 years (Figure 2).

Figure 1.

The correlation between surgical trauma and persistent stromal scarring. (a) Surgical still image demonstrating traction on overlying stroma from grasping forceps, light reflex demonstrates downwards traction. (b) Slit lamp photograph demonstrating corresponding area of posterior stromal scarring and fibrosis persisting at 12 months postsurgery. (c) Surgical still image demonstrating scoring of stroma with Sinskey hook. Light reflex demonstrates upwards indentation. (d) Slit lamp photograph demonstrates curvilinear stromal scar in corresponding area. This was a persistent focus of edema in healing phase.

Figure 2.

Posterior stromal nodules visible in cases scored with a Sinskey hook at the Descemetorhexis margin. (a) Anterior segment optical coherence tomography demonstrating hyperreflective nodule at descemetorhexis margin. Nodule is sub Descemet's in parts suggesting stromal origin. (b) Corresponding slit lamp image at 3 months post surgery, nodules seen as whitish opacities at descemetorhexis margin. (c) Same patient, 4 years postsurgery demonstrating flattening of nodule with reduced reflectivity. (d) Slit lamp image 4 years post surgery demonstrating fading of nodules.

The assumption therefore was that surgical trauma to the stroma initiated an unpredictable healing response favoring fibrosis, possibly mediated by stromal keratocytes. A surgical technique to avoid stromal contact was felt necessary.

Unpublished in-vitro work also demonstrated a more favorable healing response in cases without surgical trauma to the stroma. Specular microscopic analysis of the descemetorhexis margin created with both scoring technique and a peeling technique was analyzed utilizing human donor tissue consented for research and not fit for transplantation. In techniques in which constant pressure is created during Descemet's scoring (trephination or scoring) we observed the creation of a stromal trench, presenting a possible challenge to cell locomotion. Loss of cells in the stripped area was of course anticipated. In scoring technique, loss of cells on the host side of the wound was also observed, indicating some trauma is sustained on both sides of the stromal trench (Figure 3a and c). In descemetorhexis wounds created with a peeling technique, preservation of cell morphology was observed to the very margin of the wound (Figure 3b and d).

Figure 3.

Specular microscopic images obtained with a Nikon CCD camera on light microscope connecting to computer (Software Tomey EM-1020 version 1.2, Nagoya, Japan). Human donor corneas with Descemetorhexis created via scoring (a and c) or peeling (b and d). Note creation of a trench with scoring techniques and loss of cells on host side of margin. Note peeling techniques with preservation of cells to wound edge.

Based on our experience we strongly recommend using a peeling technique, both to maximize cell preservation and migration. This recommendation is reinforced by Davies et al.,[45] who found that in their cohort all cases who failed to heal after DSO had the common factor of a 360-degree scoring technique followed by stripping, conversely all cases stripped without scoring cleared successfully.

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