The learning curve for Descemet membrane endothelial keratoplasty performed by two experienced corneal surgeons: a consecutive series of 40 cases

Abstract

Purpose: To describe the learning curve for Descemet's membrane endothelial keratoplasty (DMEK) in the Rotterdam Eye Hospital and to evaluate safety and visual outcome. Methods: This was a single-centre prospective study of 40 consecutive patients with Fuchs' endothelial dystrophy who underwent a DMEK procedure in the Rotterdam Eye Hospital. The performance of two corneal surgeons, each conducting their first series of 20 procedures, was examined with the cumulative summation test for the learning curve (LC-CUSUM). The surgical procedure was considered unsuccessful when >30% of the graft was not attached at any time during the first 12 postoperative weeks and a mixture of SF 6 (20%) and air (80%) had to be injected in the anterior chamber (rebubbling) to reattach the graft. Also assessed were visual outcome, intraocular pressure and peri-and postoperative complications. Results: In total, nine rebubbling procedures were performed in seven eyes. Following repeated rebubbling, two eyes did not achieve a satisfactory result and secondary surgery was required to restore visual function. Complications were usually manageable. The last 13 DMEK procedures (33%) of this series did not require rebubbling. After 3 months, 86% of the eyes had reached a Snellen visual acuity of 0.5 or more. Conclusion: Together with the two surgeons' personal experience, the aggregate learning curve was considered to justify incorporation of Descemet membrane endothelial keratoplasty as a regular option of the standard of care for endothelial dysfunction in the Rotterdam Eye Hospital.Key words: cornea surgery -cumulative summation test for the learning curve -descemet membrane endothelial keratoplasty -learning curve Acta Ophthalmol. 2020: 98: 74-79

Cumulative Sum Analysis of the Learning Curve of Ptosis Surgery: External Levator Advancement versus Müller Muscle-conjunctival Resection

“…CUSUM is a statistical tool, which is increasingly used to objectively evaluate the learning curves of surgical techniques [11][12][13][14][15][16][17][18][19][20][21]. It enables us to quantitatively compare two surgical methods (in this case, ELA vs. MMCR) using statistical process control method depending on consecutive operations [16,17].…”

“…However, more objective analytic methods are required when comparing two different surgical techniques. Therefore, the cumulative sum (CUSUM) analysis has been developed to assess the learning curves of surgical procedures and is accepted in ophthalmology and many surgical fields [11][12][13][14][15][16][17]. CUSUM analysis, which is a statistical process control method, provides an objective and quantitative evaluation of surgical learning curves [11][12][13][14][15][16][17][18][19][20][21].…”

Effects of Combined Cataract Surgery on Outcomes of Descemet's Membrane Endothelial Keratoplasty: A Systematic Review and Meta-Analysis

“…After excluding 96 ineligible studies, 36 studies ( n = 11,401 eyes) were included in this systematic review. These included 17 non-randomized studies comparing DMEK alone to “triple DMEK” ( n = 8,304 eyes) with a mean follow-up duration of 12.8 ± 15.9 months (ranged, 6–60 months) ( 21 , 22 , 34 – 48 ), 14 studies on DMEK ( n = 2,609 eyes) with a mean follow-up duration of 20.0 ± 21.9 months (ranged, 3–42 months) ( 49 – 62 ), and five studies on “triple DMEK” ( n = 495 eyes) with a mean follow-up duration of 8.0 ± 3.4 months (ranged, 6–12 months) ( 63 – 67 ). Studies included were conducted at The Netherland (12 studies), Germany (nine studies), United States of America (seven studies), Canada (two studies), Egypt (one study), France (one study), Italy (one study), Nepal (one study), Spain (one study), United Kingdom (one study), and a multicenter study (23 countries).…”

“…The meta-analysis demonstrated that there was no statistical difference between DMEK alone and “triple DMEK” in terms of postoperative re-bubbling rate (RD −0.06; 95% CI: −0.13 to 0.00; I 2 = 73%; p = 0.07; Figure 4A ). Based on the findings of non-comparative studies, the overall re-bubbling rate following DMEK was estimated at 3.9% (95% CI: 1.9–5.8; n = 950 eyes from five studies; Figure 4B ) ( 52 , 55 , 58 , 59 , 62 ). No relevant data was available from “triple DMEK” studies.…”

“…Amongst the non-comparative DMEK studies, four studies ( n = 1,085 eyes) and five studies ( n = 1,152 eyes) that reported the rate of complete and partial graft detachments postoperatively respectively ( 52 , 58 , 59 , 61 , 62 ). The overall rate of complete and partial graft detachment was 8.3% (95% CI: 4.2–12.4) and 8.3% (95% CI: 5.1–11.5), respectively ( Figures 4C,D ).…”