角膜后弹力膜内皮移植术研究进展

角膜后弹力膜内皮移植术由于具有相对较低的移植排斥率以及较好的视力预后等优势,目前已成为部分发达国家治疗角膜内皮失代偿的主流手术方式,但限于手术难度较高,学习曲线较长,中国人前房偏浅,加之国内角膜内皮病变往往合并有其他较复杂的眼部疾病,目前国内尚未普遍开展这一手术。本文就角膜后弹力膜内皮移植术的手术适应证、供体植片制备(...     

Graft survival and endothelial outcomes in the new era of endothelial keratoplasty

Corneal endothelial cells do not proliferative in?vivo sufficiently to enable endothelial regeneration, and thus diseases of the corneal endothelium, which cause poor vision and discomfort, require treatment by transplantation of cadaveric donor corneal endothelial cells. The two major goals of any corneal transplant procedure are to restore vision and to promote longevity of the donor cornea by maintaining a healthy donor endothelial cell density. Over the last decade, the surgical treatment for endothelial disease has rapidly evolved toward endothelial keratoplasty, or selective tissue transplantation, and away from full-thickness penetrating keratoplasty (PK). While endothelial keratoplasty offers distinct advantages over PK in terms of visual outcomes and a smaller incision, the new surgical manipulations of the fragile donor tissue cause significant donor endothelial cell trauma. As a result, donor endothelial cell loss is much higher during the first month after Descemet stripping endothelial keratoplasty (DSEK) compared to after PK, and the primary (or more appropriately, iatrogenic) graft failure rate of 5% remains unacceptably high. Nevertheless, the rate of endothelial cell loss rapidly decreases beyond 6 months after DSEK, and thus endothelial cell loss at 5 years after DSEK appears to be lower than that at 5 years after PK. In the absence of primary (iatrogenic) graft failure, graft survival through 5 years after DSEK is similar to that after PK. Given the promising longer-term endothelial outcomes of DSEK, the quest for optimizing the visual outcomes has spurred interest in Descemet membrane endothelial keratoplasty (DMEK). While early results after DMEK suggest better visual outcomes than after DSEK, the technique needs to be simplified, and longer-term outcomes must show an advantage over DSEK with respect to vision, endothelial cell loss, and graft survival. DMEK also has a high rate of primary (iatrogenic) graft failure, and additional donor tissue wastage occurs when preparation of DMEK grafts is unsuccessful. This review discusses endothelial keratoplasty techniques and the associated endothelial outcomes.     

自动板层刀辅助的后弹力层前膜角膜内皮移植术

角膜内皮移植已成为治疗角膜内皮病变的首选方法.作为目前主流的2种角膜内皮移植手术——后弹力层剥除自动板层刀制备的角膜内皮移植术和后弹力层角膜内皮移植术,前者手术操作易于掌握,但角膜植片仍带有部分基质;后者术后视觉质量好,但手术操作较难掌握,二次手术率较前者高.大气泡和自动板层刀辅助的后弹力层前膜角膜内皮移植术在自动板层刀制备角膜内皮植片的基础上,用大气泡法暴露中央6.5 mm直径的后弹力层前膜,本术式既有后弹力层角膜内皮移植术后的视觉效果,手术操作又易于掌握,值得推广.     

Outcomes of the first 250 eyes of Descemet membrane endothelial keratoplasty: Canadian centre experience

Objective

To report and analyze the clinical outcomes of the first 250 cases of Descemet membrane endothelial keratoplasty (DMEK).

Causes of primary donor failure in descemet membrane endothelial keratoplasty

PURPOSE: To determine the causes of primary failure of donor Descemet membrane transplants in Descemet membrane endothelial keratoplasty (DMEK). DESIGN: Laboratory and clinical study. METHODS: From a larger series of eyes that underwent DMEK for Fuchs endothelial dystrophy or bullous keratopathy, 11 transplanted corneas did not clear within the first week after surgery. During a secondary 'Descemet stripping endothelial keratoplasty' procedure, the first graft was carefully removed and analyzed with light microscopy. For each patient, the surgical video of the initial DMEK procedure was analyzed to determine the cause of transplant failure. RESULTS: With light microscopy, all but two explanted transplants had a endothelial cell density of 1700 cells/mm2 or higher. Three Descemet grafts may have been positioned upside down and three may have failed due to manipulation. One transplant could not be properly attached onto the recipient posterior stroma because of insufficient air-support in a post-vitrectomy eye. For four eyes, no obvious cause of failure could be determined. CONCLUSION: Unexpectedly, graft failure after DMEK may not primarily result from tissue damage during implantation and associated endothelial cell loss. Detached grafts may therefore be managed by early reposition. When the graft is attached after surgery but fails to clear, secondary surgical intervention may be postponed, because these corneas may clear spontaneously after several weeks.     

Identifying causes for poor visual outcome after DSEK/DSAEK following secondary DMEK in the same eye

Purpose: To identify causes of reduced visual acuity after Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and to determine whether such eyes can be successfully ‘repaired’ with a secondary Descemet membrane endothelial keratoplasty (DMEK). Methods: Twelve eyes of 12 patients, who underwent secondary DMEK to manage poor visual outcome after initial DSEK/DSAEK, were evaluated with biomicroscopy, Pentacam imaging, and specular and confocal microscopy, before and at 1, 3 and 6 months after DMEK. Results: Four causes of reduced optical quality of the transplanted host cornea could be identified in DSEK/DSAEK: five eyes (42%) showed large host‐Descemet remnants within the visual axis during surgery; six eyes (50%) irregular graft thickness; six eyes subtle ‘stromal waves’; and nine eyes (75%) high reflectivity at the donor‐to‐host interface. After DMEK graft replacement, all corneas cleared and achieved a best corrected visual acuity of ≥20/25 (≥0.8), except for one with a partial Descemet graft detachment. Pachymetry values decreased from 670 (±112) μm before to 517 (±57) μm after secondary DMEK. Higher‐order aberrations (Coma and Trefoil) at the posterior surface tended to be lower (p = 0.07) in DMEK grafts than in DSEK/DSAEK grafts. Conclusion: Host‐Descemet remnants at the donor‐to‐host interface, interface reflectivity, graft thickness irregularity and donor stromal contraction may contribute to poor visual outcome after DSEK/DSAEK, without causing permanent host corneal damage, as in most cases, complete visual recovery could be achieved by performing a secondary DMEK.     

后弹力层角膜内皮移植术应用与手术技术

角膜内皮移植(endothelial keratoplasty,EK)是针对内皮细胞功能障碍的靶向性治疗方法.目前已成为国际上治疗角膜内皮病变的首选方法.而后弹力层角膜内皮移植术(Descemet's membrane endothelial keratoplasty,DMEK)是目前EK最新技术,也称为小切口角膜内皮移植术,从解剖学角度完美恢复了角膜组织的正常结构,可更好更快恢复视力,且术后排斥反应显著降低,受到了广泛关注和认可.然而,DMEK作为一项新技术,虽然具有显著的优点,也面临着技术上的挑战.最受关注的是供体制备过程中内皮片的丢失、植入受体的展开和位置调整.目前随着手术方法和设备的不断改进,植入技术不断改进,学习曲线正在逐渐减低,越来越多的眼科医生掌握了该技术.由于角膜材料与手术适应证等限制,目前我国尚无开展DMEK的报道.     

Therapie von Hornhautendothelerkrankungen mittels DMEK und UT-DSAEK

Various techniques for posterior lamellar keratoplasty have been established for the clinical routine and continuously improved during the last 15 years so that an extremely rapid recovery of vision is possible due to very thin transplants. Descemet membrane endothelial keratoplasty (DMEK) is the method of choice for simple corneal endothelial diseases and has already been applied in complex conditions of the anterior segment. The learning curve for DMEK is comparatively long and the risk of complications in complex anterior segment pathologies is higher than in Descemet’s stripping automated endothelial keratoplasty (DSAEK); however, DMEK results in better visual outcome and less graft rejections than DSAEK. The latest evolution in posterior lamellar transplant surgery is ultrathin DSAEK (UT-DSAEK), where the grafted lamella is much thinner than in conventional DSAEK. Currently available data suggest that the resulting visual acuity after UT-DSAEK is close to the visual acuity seen after DMEK; however, studies comparing the results after DMEK and UT-DSAEK are so far lacking. Whether the transplantation of these very thin DSAEK grafts also results in endothelial cell densities and graft rejection rates comparable to DMEK has to be proven.     

Graft survival and clinical outcomes of Descemet membrane endothelial keratoplasty: long-term results

International Ophthalmology - The aim is to report long-term graft survival rates and clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK). In this study 150 eyes that underwent...     

What does the future hold for the treatment of Fuchs endothelial dystrophy; will ‘keratoplasty' still be a valid procedure?

Fuchs endothelial corneal dystrophy (FECD) is a well recognized corneal disorder characterized by the presence of collagenous warts extending from Descemet membrane (guttae) and endothelial cellular dysfunction due to cell loss and/or degeneration. Because of the characteristic abnormal cell morphology as seen with specular microscopy as well as the limited regenerative capacity in vivo, the endothelial cells were considered to be ‘dystrophic''. Hence, FECD is commonly managed by replacement of the endothelium with donor tissue by means of a penetrating or endothelial keratoplasty. The latter procedure has now been refined to the isolated transplantation of a donor Descemet membrane and its endothelium, referred to as Descemet membrane endothelial keratoplasty (DMEK). Unexpectedly, clinical observation made after DMEK seemed to challenge the current concept of the state of the endothelium in FECD; we actually observed an important role for the ‘dystrophic'' host endothelium in re-endothelialization of the denuded DM, and subsequent corneal clearance. In addition, recent studies regarding the pathophysiology of FECD made us realize that the endothelial cells are not ‘dystrophic'' per se, but in the course of time may have acquired a dysfunction instead. This paper describes the rationale behind this new concept and based on this, discusses the possibilities for future, less invasive treatment modalities for FECD.     

Donor tissue preparation for Descemet membrane endothelial keratoplasty

PURPOSE: To evaluate a technique for preparing a donor Descemet membrane carrying autologous endothelium for transplantation in Descemet membrane endothelial keratoplasty (DMEK). SETTING: Netherlands Institute for Innovative Ocular Surgery, Rotterdam, The Netherlands. METHODS: A 9.5 mm diameter DM carrying autologous endothelium was stripped from 10 corneoscleral rims that had been organ cultured for 1 week. The endothelial cell density (ECD) was evaluated with light microscopy before and immediately after DM was stripped and during 4 additional weeks of organ culture. RESULTS: The mean ECD was 2701 cells/mm(2) +/- 302 (SD) before and 2719 +/- 322 cells/mm(2) immediately after DM was stripped and declined from 2604 +/- 352 cells/mm(2) after 1 week to 2190 +/- 768 cells/mm(2) after an additional 4 weeks of organ culture (n = 10). Typical "endothelial streaks," ie, linear cellular disruptions observed immediately after DM was stripped, showed complete regeneration after the second culture period. CONCLUSIONS: Descemet grafts for transplantation in DMEK procedures can be surgically prepared from organ-cultured corneal rims and stored for an additional 3 weeks with acceptable endothelial cell loss. Because the donor tissue can be dissected directly from organ-cultured corneoscleral rims, donor preparation for DMEK can be readily accessible to most corneal surgeons.     

Aclaramiento corneal espontáneo tras desprendimiento del injerto en DMEK

Descemet Membrane detachment is a potential complication after Descemet Membrane Endothelial Keratoplasty (DMEK). Here, we present a unique case of a DMEK surgery in a complicated eye that suffered a nearly complete DMEK graft detachment and later a graft opacification with a pseudo-anterior chamber. In Mid-November 2020, a planned DMEK was performed in a 64-year-old male patient due to corneal decompensation. Four months after DMEK, a fibrotic DMEK graft was seen across the anterior chamber with a pseudo-anterior chamber; however, the recipient cornea showed complete clearance with an endothelial cell count of about 1204 cells/mm² and a best-corrected visual acuity of 20/25. Three months later, we observed a significant opacification of the detached graft, and the best-corrected distance visual acuity decreased to 20/63. We proceeded with the graft removal without performing a second DMEK. Ten months after graft removal, the cornea remained clear with an endothelial cell count of about 510 cells/mm², and the best-corrected visual acuity was 20/25.     

Preliminary clinical results of Descemet membrane endothelial keratoplasty

PURPOSE: To describe the preliminary clinical results of selective transplantation of organ cultured, donor Descemet membrane (DM) carrying autologous corneal endothelium through a 3.5-mm incision, tentatively named Descemet membrane endothelial keratoplasty (DMEK), for the management of corneal endothelial disorders. DESIGN: Nonrandomized clinical study. METHODS: In 10 patients with Fuchs endothelial dystrophy or pseudophakic bullous keratopathy, DMEK was performed. A 3.5-mm clear corneal tunnel incision was made, the anterior chamber was filled with air, and DM was stripped off from the posterior stroma. A 9.0-mm diameter DM roll was harvested from an organ cultured donor corneo-scleral rim, and inserted into a recipient anterior chamber. The donor tissue was gently unfolded, positioned onto the posterior stroma, and secured by completely filling the anterior chamber with air for 30 minutes. RESULTS: At one month, six eyes had a best-corrected visual acuity of 0.5 (20/40) or better, and three eyes reached 1.0 (20/20). At six months, the endothelial cell density averaged 2030 (+/-373) cells/mm(2) (n = 7). Three eyes showed a complete detachment of the donor tissue in the early postoperative course that was managed by removal of the transplant and a secondary Descemet stripping endothelial keratoplasty procedure. CONCLUSION: DMEK may have potential to become the most preferable technique to manage corneal endothelial disorders, because it provides quick and nearly complete visual rehabilitation. Because the donor tissue required can be prepared from organ cultured corneo-scleral rims, the procedure may be readily accessible to most corneal surgeons.     

Donor descemet membrane detachment after endothelial keratoplasty

PURPOSE: To describe histopathologic characteristics of an endothelial keratoplasty (EK) that was performed to treat a previously failed penetrating keratoplasty (PK) and in which the cornea failed to clear after partial detachment of Descemet membrane from the EK donor button. The Descemet membrane and endothelium from the PK were intentionally retained during the EK procedure. METHODS: After EK, the cornea failed to fully clear in 5 months, and a PK was performed. The removed corneal button was grossly described and routinely processed for hematoxylin-eosin (H&E) and periodic acid-Schiff (PAS) staining, with photographs taken of any pertinent findings. RESULTS: Grossly on the endothelial side, there was some adherent iris pigment delineating an off-center fold in the EK Descemet membrane, consistent with intraoperative observation of a fold across the width of the donor button and postoperative slit-lamp images showing partial detachment of Descemet membrane. Microscopic examination revealed a recipient corneal button from a prior PK centrally and EK donor button attached posteriorly. Descemet membrane was not stripped from the prior PK during EK and was intact. No endothelial cells were detected on the PK Descemet membrane. The anterior stromal surface of the EK was well apposed to the prior PK Descemet membrane, with no pseudoanterior chamber or cleft of any type noted between them. The EK Descemet membrane had a central fold, and the endothelium was markedly attenuated. CONCLUSION: The EK graft was well apposed with apparent good adherence to the recipient's prior failed PK, and early endothelial failure was attributable to partial Descemet membrane detachment.     

DMEK: posteriore lamelläre Keratoplastiktechnik

Background

Penetrating keratoplasty is at present the gold standard for surgical treatment of corneal endothelial pathologies but tremendous progress has been made in recent years in improving the technology of (posterior) lamellar keratoplasty techniques, such as Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

A review of the literature was carried out using PUBMED and own clinical and experimental data.

Results

Isolated transplantation of Descemet’s membrane with endothelial cells after stripping the host Descemet’s membrane is a new surgical technique for Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation seems to be faster and better with DMEK compared to penetrating keratoplasty.

Conclusion

Posterior lamellar keratoplasty techniques such as DMEK will replace penetrating keratoplasty as the gold standard for treatment of a large segment of corneal endothelial pathologies.     

The correct graft orientation during descemet membrane endothelial keratoplasty (DMEK) using the “bubble-tap” technique

Purpose

To demonstrate a novel, alternative endothelium Descemet membrane layer (EDM) orientation method in Descemet membrane endothelial keratoplasty (DMEK) that does not involve prior ink or trepanation marking of the graft, or intraoperative ocular coherence tomography (OCT) guided graft implantation during surgery, thus preventing the occurrence of an upside-down graft implantation that leads with certainty to primary graft failure.

Methods

From 2017 to early 2020, 500 eyes underwent DMEK operation using the “bubble-tap” technique first described from Dr. Perdikakis in the department of ophthalmology of St.-Johannes- Hospital in Dortmund in Germany. Primary graft failure and re-bubbling results following “bubble-tap” assisted DMEK are presented.

Results

Primary graft failure due to upside-down graft implantation was not observed in any patient. Re-bubbling was performed in 4.8% of the eyes. In 1.8% of the cases, a re-DMEK was performed due to a graft failure.

Conclusion

The “bubble-tap” technique is a novel, reliable and easy to master orientation method of EDM that enables the surgeon to perform DMEK with safety even in complicated cases with poor visibility in the anterior chamber, while it yields superior or equal results in comparison to other graft marking methods or intraoperative OCT-guided graft implantation.

     

Standardized "no-touch" technique for descemet membrane endothelial keratoplasty

We describe a standardized technique for "no-touch" isolated Descemet membrane transplant, ie, Descemet membrane endothelial keratoplasty (DMEK). All essential steps, including patient preparation and descemetorhexis as well as DMEK graft implantation, orientation, unrolling, centering, appositioning, and fixation, are described in detail. In the management of Fuchs endothelial dystrophy, the technique may provide a best-corrected visual acuity of 20/25 or better (≥ 0.8) in three-quarters of cases and an endothelial cell density of about 1800 to 2000 cells/mm(2) at 6 months after surgery. No-touch DMEK may therefore be a safe and effective procedure for the treatment of corneal endothelial disorders, making endothelial keratoplasty accessible to most corneal surgeons without requiring major investments while providing an unprecedented visual rehabilitation rate and outcome.     

Deep anterior lamellar Keratoplasty

Keratoconus is a disease causing increased steepening of the cornea resulted in irregular astigmatism. Treatment options are Glasses, Hard contact lenses, Cross linking, Intracorneal Segments insertion, Refractive surgery (Gilda et al., 2008), or Keratoplasty. Lamellar Keratoplasty (LKP) can be a better choice to manage cases of moderate and some cases of severe Keratoconus without deep scarring and severe thinning, also in cases of corneal scarring not involving the deeper layers of the cornea. LKP is a corneal graft technique consisting of transplantation of partial-thickness donor tissue, devoid of endothelium, Descemet membrane (DM), and rear stroma into a recipient healthy stromal bed after dissection of pathologic anterior stroma. However, deep lamellar Keratoplasty (DLKP) is a surgical method that completely removes pathologic corneal stroma tissue down to the DM, followed by transplantation of donor cornea without endothelium over the host bed. DLKP has a number of advantages over penetrating Keratoplasty (PKP). Because it does not violate the intraocular structures of the eye, it diminishes or eliminates the chance of postoperative glaucoma, cataract formation, retinal detachment, cystoids macular edema, expulsive choroidal hemorrhage and epithelial ingrowths. Furthermore, this procedure avoids the replacement of host endothelium with donor endothelium and thus precludes endothelial graft rejection, with comparable visual outcomes and low rate of chronic endothelial cell loss compared to PKP.     

A Comprehensive Review of Postoperative Management of Descemet’s Membrane Endothelial Keratoplasty

ABSTRACT

Introduction: As Descemet’s Membrane Endothelial Keratoplasty (DMEK) continues to gain in popularity, the postoperative management of DMEK surgery is becoming increasingly important, as these management strategies may affect postoperative success rates. Materials and Methods: This article reviews the current evidence for postoperative management in DMEK. Results: There are variable strategies in the postoperative management of DMEK as it relates to postoperative positioning, need for and timing of rebubble, tamponade agent utilized (both primarily and at rebubble), steroid agent and tapering schedule, timing of secondary regraft when required, and postoperative monitoring. Discussion: While a great deal of attention is rightly devoted to developing better surgical techniques for DMEK, we believe it is also crucial to develop a better understanding of and evidence-based best practice in the postoperative management of DMEK, as this may have important implications for outcomes.     

Two-year clinical outcome after Descemet membrane endothelial keratoplasty using a standardized protocol

Purpose:The purpose of this study is to evaluate 2-year clinical outcome after Descemet membrane endothelial keratoplasty (DMEK) in a variety of endothelial dysfunctions using a standardized protocol.Methods:From a group of 230 eyes which underwent DMEK for Fuchs'' endothelial corneal dystrophy (FECD), aphakic and pseudophakic bullous keratopathy, failed full thickness corneal transplants, ICE syndrome, failed DSEK, and TASS the clinical outcomes [best spectacle-corrected visual acuity (BSCVA), central endothelial cell density (ECD)] were evaluated before, and at 6, 12, and 24 months and the success rate, failure rate and postoperative complications were also analyzed.Results:Out of 230 eyes, 144 eyes (70%) had BSCVA 6/9 or better 2 years postoperatively. Mean donor ECD was 2692.23 (range, 2300–3436) cells/mm² preoperatively, which was reduced to 1433.64 (range, 619.0–2272.0) cells/mm² 2 years after DMEK surgery, indicating a mean reduction of 1258 cells/mm² (46%) in ECD.Conclusion:DMEK is a highly successful surgical procedure when following a standard protocol for treating diseases of the corneal endothelium providing a near perfect anatomic restoration and a high degree of visual rehabilitation.