Surgical Pearls in Managing Surface Orientation During Corneal Patch Graft
Mona Bhargava, Pragya Shambhawi, Debasmita Bera, Neha ChaudharyAbstract
Background:
Full-thickness corneal patch grafts restore ocular integrity in eyes with perforation or structural instability, serving as a tectonic procedure to preserve the globe in emergencies such as immune-mediated peripheral melts, descemetoceles, and post-traumatic perforations. [1-6] The surgical approach to corneal perforation depends on the size and location of the defect. [3-7] Small patch grafts (diameter <6 mm) are increasingly used in these urgent settings. However, as diameter decreases, sagittal height reduces from 1.20 mm at 7.5 mm to 0.15 mm at 3.0 mm, rendering the normally reliable convex epithelial and concave endothelial surfaces geometrically indistinguishable, thus creating a risk of inadvertent graft inversion. [8]
Purpose:
This video aims to raise awareness about intraoperative complications while performing a small corneal patch graft. It also features the concept of geometrically predictable risk of inadvertent graft inversion in small-diameter full-thickness corneal patch grafts, and presents a simple, reliable protocol applicable in emergency surgical settings to prevent such complications.
Synopsis:
The video explains the geometric basis of orientation loss using sagittal height calculations across graft diameters, [9] demonstrating how corneal buttons under 6 mm flatten to near planarity and can flip effortlessly during handling, especially under the compounding pressures of poor illumination, hypotony, and operative urgency. [9,10] When inversion occurs, the endothelium faces anteriorly, potentially compromising graft clarity and tectonic function due to poor graft–host apposition. [9,10] A stepwise prevention protocol is then described, ranked as per reliability, along with demonstration videos. Each step is easily applicable and takes minimal additional time on the operating table. The video advocates institution-level written checklists mandating pre-trephination marking for all patch grafts under 6 mm. [3,6]
Highlights:
Sagittal height of donor buttons falls below perceptible limits at diameters under 4.5 mm, making tactile and visual orientation unreliable. [8] Inadvertent endothelial inversion is a geometrically predictable yet preventable cause of tectonic graft failure in emergency settings. [9,10] Pre-trephination anterior surface ink marking is a simple and reliable orientation method that can remain visible during media immersion and handling. Institutional written checklists enforcing pre-trephination marking for grafts under 6 mm are recommended as a systemic safety measure. [3,6]