DISCUSSION
detachments, tightness
DETACHMENTS, SCARRING, DECAY
We report an analysis of surgical video recordings to explore risk factors for GD and rebubbling after DMEK. This study provides a rare opportunity to analyze surgical DMEK videos in-depth, in a well-controlled cohort of corneal transplant procedures performed by various surgeons in 3 clinics, with well-defined procedural trial parameters. We focused on the contribution of surgical manipulations, tissue handling, and (unnoticed) practice pattern variations to identify risk factors for GD and rebubbling. GDs have a notorious multifactorial origin, and several strategies to investigate this are reported, for example, case–control,The main findings of this study are that direct manipulation of the graft (ie, judicious grabbing with a pair of forceps) is not associated with poor surgical outcome nor was overlap of the graft with host Descemet membrane. The gas-bubble size at the end of surgery did seem clinically relevant: bigger is better in maintaining an attached graft. Commensurate to the primary outcomes of the ADVISE trial,There is limited evidence regarding the causality of surgical decision making and detachment/rebubbling rates. Our results underlines that it is very difficult to predict GD or rebubbling, based on how the surgery faired. Several recommended practices were not supported by our results, such as not directly manipulating the graft and preventing overlap with host Descemet membrane. One of those recommended practices is avoidance of direct manual manipulation of the graft, which may lead to endothelial damage and GD.In our study, we did not find an association between graft overlap with recipient Descemet membrane and GD or rebubbling contradicting the findings of Rock et al On the other hand, our results support that a larger gas-bubble size may be protective for a GD as previously reported by Leon et al and Cirkovic et al.Endothelial decay at 3 months and 6 months was higher in eyes with a partial GD compared with eyes with an attached graft and eyes that required a rebubbling. A similar association between partial detachments and endothelial cell loss was found by Baydoun et alFurthermore, several limitations should be addressed. This study was a post hoc analysis of a trial that was not powered to determine associations between intraoperative factors and GD/rebubbling. Notwithstanding, the data were derived from a well-controlled sample of corneal transplant procedures and the video analysis enables an objective in-depth observation of the surgical course. In this study, we focused on intraoperative factors affecting graft disadherence. However, an analysis including recipient and additional donor factors may reveal additional insights, including graft quality or posterior stromal scarring. Several factors were assessed in the video analysis (eg, presence of Descemet remnants and stromal damage resulting from the descemetorhexis), although not included in the analysis because the incidence of these factors either was low or could not reliably be estimated in the video analysis. Similarly, some factors that were scored are inherently subjective, for example, the surgeons' assessment of how loose/tight the DMEK rolls were. What is considered tight or loose DMEK roll by 1 surgeon can be different for another surgeon. In this study, we cross-checked the video feed with the surgeons assessment; however, as this process is subjective, we chose not to report on the scroll tightness. During determining the graft shape, grafts were only classified as a tight roll if the graders' assessment on the video image matched the surgeons' assessment. Information on noncompliance of the patient and resorption time of the gas bubble was not collected and could not retrospectively be retrieved.In conclusion, using a structured video analysis, we explored intraoperative determinants for GD and rebubbling after DMEK. Our analysis revealed that the gas-bubble size and graft shape/geometry seem to be relevant clinical factors. GD and rebubbling were not associated with the degree of graft manipulation, graft positioning, surgical iridectomy, or overpressuring the eye.