Descemet-Stripping Automated Endothelial Keratoplasty

Delivering Endothelial Keratoplasty Grafts: Modern Day Transplant Devices

PURPOSE

To summarize the graft loading, transporting and delivery devices used for endothelial keratoplasty (EK).

METHODS

A literature search of electronic databases was performed.

RESULTS

New techniques and devices have been introduced and implemented to prepare, load, transport and transplant the grafts for EK. The advantages are not only limited to the surgical theatre but also widely spread across the eye banking field. Investigation of advanced materials and designs have been rapidly growing with continuous evolution in the field of eye banking and corneal transplantation. Innovative techniques and modern devices have been evaluated to reduce the endothelial cell loss and increase the precision of the transplant in order to benefit both surgeons and the patients.

CONCLUSIONS

It is extremely important to reduce any potential wastage and optimize the use of every available donor cornea due to the limited availability of healthy cadaveric donor corneas required for transplants. As a result, the use of pre-cut and pre-loaded grafts supplied by the eye banks in calibrated devices have been gaining momentum. Innovation in the field of bioengineering for the development of new devices that facilitate excellent clinical outcomes along with reduction in learning curve has shown promising results.

A New User-Friendly and Affordable Method in Descemet Stripping Endothelial Keratoplasty

Aims

To describe a new technique in Descemet Stripping Automated Endothelial Keratoplasty (DSAEK).

Materials and Methods

In this technique, we use easily available materials (mainly a Nelaton tube) to make an injector for loading DSAEK lenticule and also easily pulling it (using a gauge 23 needle) into the eye. In this paper, we report outcomes of this technique in four cases.

Results

Using these available instruments could easily lead to a clear postoperative cornea. Mean Endothelial Cell Density (ECD) loss at sixth postoperative month was 26%.

Conclusion

We proposed a novel effective user-friendly and affordable technique to perform DSAEK.

Corneal Endothelial Cell Loss in Femtosecond Laser-assisted Descemet's Stripping Automated Endothelial Keratoplasty: A 12-month Follow-up Study

Background:

Descemet's stripping automated endothelial keratoplasty (DSAEK) surgery offers a more standardized approach and reliable method to create corneal grafts with an instrument such as a microkeratome. With the development of Descemet's membrane endothelial keratoplasty, an excellent clinical outcome is seen in the treatment of corneal endothelial dysfunctions, which indicates that thinner corneal graft results in better clinical outcome. With the recent development of the femtosecond laser, ultrathin corneal graft preparation has become possible. This study aimed to report corneal graft endothelial cell loss (ECL) in a large series of cases undergoing DSAEK with femtosecond laser-assisted corneal graft preparation within a 12-month period.

Methods:

This study was designed as a prospective, noncomparative, interventional case series. Totally 126 consecutive eyes with endothelial failure of 120 patients, who had corneal endothelial decompensation and underwent femtosecond-assisted DSAEK using the VisuMax femtosecond laser system, were included in the study. Central endothelial cell density (ECD) was recorded postoperatively at 2 weeks (n = 126), 1 month (n = 126), 3 months (n = 110), 6 months (n = 101), and 12 months (n = 71) and then compared with the preoperative eye bank measurements. Pre- and postoperative central ECDs were evaluated using Heidelberg retina tomography-III confocal microscopy. ECL was calculated for each postoperative time point. Graft thickness was examined using anterior segment-optical coherence tomography.

Results:

Mean preoperative cell count was 3383 ± 350 cells/mm². Mean postoperative cell counts were 2382 ± 707 cells/mm², 2179 ± 685 cells/mm², 2074 ± 688 cells/mm², 1884 ± 662 cells/mm², and 1723 ± 624 cells/mm² at 2 weeks, 1, 3, 6, and 12 months, respectively; these represented the ECL of 29.7 ± 19.7%, 35.4 ± 19.5%, 38.6 ± 19.8%, 44.3 ± 18.9%, and 48.9 ± 18.4% at the each corresponding time point. The mean corneal graft thickness after surgery was 142 ± 48 μm, 118 ± 41 μm, 108 ± 37 μm, 100 ± 32 μm, and 99 ± 32 μm at each corresponding study visit, respectively. There was no correlation between corneal graft thickness and corneal ECL (R = 0.039).

Conclusions:

Corneal ECL remained relatively stable up to 12 months after femtosecond laser-assisted ultrathin DSAEK in a large case series. No correlation between cell loss and corneal graft thickness was found, which indicated that corneal graft preparation by the femtosecond laser was safe. ECL was faster within the first 6 months and relatively stable thereafter.

Vulnerability of corneal endothelial cells to mechanical trauma from indentation forces assessed using contact mechanics and fluorescence microscopy

Corneal endothelial cell (CEC) loss occurs from tissue manipulation during anterior segment surgery and corneal transplantation as well as from contact with synthetic materials like intraocular lenses and tube shunts. While several studies have quantified CEC loss for specific surgical steps, the vulnerability of CECs to isolated, controllable and measurable mechanical forces has not been assessed previously. The purpose of this study was to develop an experimental testing platform where the susceptibility of CECs to controlled mechanical trauma could be measured. The corneal endothelial surfaces of freshly dissected porcine corneas were subjected to a range of indentation forces via a spherical stainless steel bead. A cell viability assay in combination with high-resolution fluorescence microscopy was used to visualize and quantify injured/dead CEC densities before and after mechanical loading. In specimens subjected to an indentation force of 9 mN, the mean ± SD peak contact pressure P₀ was 18.64 ± 3.59 kPa (139.81 ± 26.93 mmHg) in the center of indentation and decreased radially outward. Injured/dead CEC densities were significantly greater (p ≤ 0.001) after mechanical indentation of 9 mN (167 ± 97 cells/mm²) compared to before indentation (39 ± 52 cells/mm²) and compared to the sham group (34 ± 31 cells/mm²). In specimens subjected to "contact only" - defined as an applied indentation force of 0.65 mN - the peak contact pressure P₀ was 7.31 ± 1.5 kPa (54.83 ± 11.25 mmHg). In regions where the contact pressures was below 78% of P₀ (<5.7 kPa or 42.75 mmHg), injured/dead CEC densities were within the range of CEC loss observed in the sham group, suggesting negligible cell death. These findings indicate that CECs are highly susceptible to mechanical trauma via indentation, supporting the established "no-touch" policy for ophthalmological procedures. While CECs can potentially remain viable below contact pressures of 5.7 kPa (42.75 mmHg), this low threshold suggests that prevention of indentation-associated CEC loss may be challenging.

Real-time assessment of corneal endothelial cell damage following graft preparation and donor insertion for DMEK

PURPOSE

To establish a method for assessing graft viability, in-vivo, following corneal transplantation.

METHODS

Optimization of calcein AM fluorescence and toxicity assessment was performed in cultured human corneal endothelial cells and ex-vivo corneal tissue. Descemet membrane endothelial keratoplasty grafts were incubated with calcein AM and imaged pre and post preparation, and in-situ after insertion and unfolding in a pig eye model. Global, macroscopic images of the entire graft and individual cell resolution could be attained by altering the magnification of a clinical confocal scanning laser microscope. Patterns of cell loss observed in situ were compared to those seen using standard ex-vivo techniques.

RESULTS

Calcein AM showed a positive dose-fluorescence relationship. A dose of 2.67μmol was sufficient to allow clear discrimination between viable and non-viable areas (sensitivity of 96.6% with a specificity of 96.1%) and was not toxic to cultured endothelial cells or ex-vivo corneal tissue. Patterns of cell loss seen in-situ closely matched those seen on ex-vivo assessment with fluorescence viability imaging, trypan blue/alizarin red staining or scanning electron microscopy. Iatrogenic graft damage from preparation and insertion varied between 7-35% and incarceration of the graft tissue within surgical wounds was identified as a significant cause of endothelial damage.

CONCLUSIONS

In-situ graft viability assessment using clinical imaging devices provides comparable information to ex-vivo methods. This method shows high sensitivity and specificity, is non-toxic and can be used to evaluate immediate cell viability in new grafting techniques in-vivo.

Finite Element Analysis of Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) Surgery Allograft to Predict Endothelial Cell Loss

PURPOSE

To develop high fidelity finite element (FE) models of the Descemet's stripping automated endothelial keratoplasty (DSAEK) allograft to estimate the stress distributions generated on the allograft during its deformed state in popular allograft insertion configurations and qualitatively correlate the stress distributions to postsurgical endothelial cell (EC) loss.

MATERIALS AND METHODS

Corneal allograft simulation was performed using ANSYS (Canonsburg, PA, USA) utilizing isotropic nonlinear hyperelastic corneal material properties to evaluate the stress distributions generated on the DSAEK allograft during popular allograft insertion configurations, namely forceps, taco, and double-coil insertion configurations. The gathered FE simulation results were qualitatively compared with published clinical studies to verify the simulation results.

RESULTS

The FE simulation results demonstrate that high stress regions predicted by FE model results correctly predict the areas of postsurgical EC loss as published in the studies available in open literature. The FE simulation stress magnitude results suggest that highest EC loss due to mechanical bending trauma occurs in double-coil configuration followed by forceps and then taco configuration.

CONCLUSIONS

The results of the presented FE simulation study highlight that allograft regions with high stress distribution demonstrate postsurgical EC loss in clinical studies. The modeling procedures presented in this research can be utilized to develop novel surgical devices/techniques that can modulate the postsurgical EC loss due to mechanical bending trauma and facilitate allograft unfolding inside the AC, thereby improving the results of the DSAEK surgical procedure.

Descemet's Stripping Automated Endothelial Keratoplasty Tissue Insertion Devices

This review study provides information regarding the construction, design, and use of six commercially available endothelial allograft insertion devices applied for Descemet's stripping automated endothelial keratoplasty (DSAEK). We also highlight issues being faced in DSAEK and discuss the methods through which medical devices such as corneal inserters may alleviate these issues. Inserter selection is of high importance in the DSAEK procedure since overcoming the learning curve associated with the use of an insertion device is a time and energy consuming process. In the present review, allograft insertion devices were compared in terms of design, construction material, insertion technique, dimensions, incision requirements and endothelial cell loss to show their relative merits and capabilities based on available data in the literature. Moreover, the advantages/disadvantages of various insertion devices used for allograft insertion in DSAEK are reviewed and compared. The information presented in this review can be utilized for better selection of an insertion device for DSAEK.

Effects of a novel push-through technique using the implantable collamer lens injector system for graft delivery during endothelial keratoplasty

Purpose

To investigate effects of a new push-through insertion method for donor lenticules using an injector system on endothelial viability ex vivo and in a clinical case series of endothelial keratoplasty.

Methods

An ex vivo delivery model was used with porcine corneoscleral rims. We compared the endothelial viability in a new push-through insertion method using the Visian Implantable Collamer Lens (ICL) injector versus that of standard forceps-assisted insertion for lenticule delivery. Twenty porcine corneal lenticules were divided into four groups by insertion method and wound size. Vital dye staining was performed and devitalized areas were semi-quantitatively assessed by digital imaging. In the clinical case series, Descemet's stripping endothelial keratoplasty (DSEK) using the push-through method was performed in seven patients and endothelial outcome was determined six months postoperatively.

Results

Mean devitalized areas for the push-through method were significantly lower than for forceps-assisted insertion through 3.2 mm incision (23.99 ± 2.17% vs. 50.48 ± 5.07%, p = 0.009) in the ex vivo model. Average endothelial cell counts of donor tissues of patients who underwent DSEK were 26.4% lower six months postoperatively.

Conclusions

Push-through delivery of donor lenticules using the Visian ICL injector system appears to be less harmful to endothelial cells than conventional forceps-assisted delivery.

Small-incision Descemet stripping automated endothelial keratoplasty: a comparison of small-incision tissue injector and forceps techniques

PURPOSE

To describe a novel, small-incision, no-fold Descemet stripping automated endothelial keratoplasty (DSAEK) graft injector and to compare complications, visual acuity, and endothelial cell loss with a forceps technique.

METHODS

An Institutional Review Board-approved, interventional, nonrandomized, consecutive case series analysis of 175 eyes undergoing DSAEK for Fuchs dystrophy and bullous keratopathy. The injector arm is prospective, and the forceps arm is retrospective. Seventy grafts were performed with a DSAEK graft injector, and 105 grafts were performed using a small-incision forceps technique. Preoperative and postoperative visual acuities at 3 and 6 months, 6-month endothelial cell counts, and complications, including graft dislocation, failure, and rejection, were recorded. Fifty-seven of 232 eyes met exclusion criteria for previous incisional corneal or glaucoma surgery.

RESULTS

There were 4 eyes (5.7%) in the injector group and 29 eyes (27.6%) in the forceps group that required a re-bubble procedure because of graft detachment. One graft (1.4%) failed in the injector group and 7 grafts (6.5%) failed in the forceps group. Excluding eyes with other ocular comorbidities (43), in the injector group 74% were 20/40 or better at 6 months and 100% were 20/60 or better. In the forceps group, 72% were 20/40 or better at 6 months and 98% were 20/60 or better. Six-month postoperative endothelial cell counts were available for 84 (46 injector and 38 forceps) eyes, with an average cell loss of 28.3% in the injector group and 44.1% in the forceps group.

CONCLUSIONS

DSAEK is an effective treatment of endothelial dysfunction. Surgical technique is important to limit endothelial cell loss and prevent complications, such as graft dislocation. The injector device has several advantages over the trifold forceps technique, including decreased endothelial cell loss, graft dislocation rate, and graft failure rate, and it reduces the DSAEK learning curve. DSAEK graft injectors likely will have a role in the future of endothelial keratoplasty.

A prospective study comparing EndoGlide and Busin glide insertion techniques in descemet stripping endothelial keratoplasty

PURPOSE

To compare a new insertion method using an EndoGlide (Angiotech/Network Medical Products) with the standard Busin glide (Moria USA) assisted insertion of the posterior lamellar corneal graft in Descemet stripping endothelial keratoplasty (DSEK).

DESIGN

Prospective, consecutive, comparative, nonrandomized study.

METHODS

Surgery was performed between October 2008 and October 2010 in 52 eyes of 52 consecutive patients with endothelial dysfunction suitable for DSEK. Twenty-two consecutive eyes underwent the new EndoGlide-assisted insertion of donor lenticule and 30 eyes underwent the surgery using the Busin glide. Six-month follow-up data are available for all patients. Clinical details, best-corrected visual acuity, manifest refraction, intraoperative and postoperative complications, and corneal endothelial cell loss were assessed at 6 months after DSEK.

RESULTS

At 6 months after surgery, the best-corrected visual acuity was similar in both groups (0.13 logarithm of the minimal angle of resolution in the EndoGlide eyes as compared with 0.15 logarithm of the minimal angle of resolution in the Busin group; P = .34). Mean spherical equivalent was 0.65 diopter (D) and 0.51 D, and mean refractory cylinder was 1.39 D and 1.08 D, respectively (P = .40). The endothelial cell loss was much lower in the EndoGlide group (25.76%) as compared with the Busin group (47.46%; P < .0001).

CONCLUSIONS

In conclusion, the new EndoGlide results in significantly less endothelial cell loss than Busin glide donor insertion in DSEK. The visual outcomes and refractive changes were similar in both groups.

Ophthalmic drug-loaded N,O-carboxymethyl chitosan hydrogels: synthesis, in vitro and in vivo evaluation

AIM

to investigate the ability of drug-loaded N,O-carboxymethyl chitosan (CMCS) hydrogels to modulate wound healing after glaucoma filtration surgery.

METHODS

the drug-loaded CMCS hydrogels were in situ synthesized using genipin as the crosslinker in the presence of 5-fluorouracil (5FU) or bevacizumab. Their structures were characterized by FTIR, ultraviolet-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). In-vitro drug release experiments and in vivo evaluation in rabbits were performed.

RESULTS

the results of FTIR, UV-vis spectroscopy and SEM analyses indicated that 5FU was encapsulated into the CMCS hydrogels that were crosslinked by genipin. The in vitro drug release experiments showed that nearly 100% of 5FU was released from the drug-loaded hydrogels within 8 h, but less than 20% bevacizumab was released after 53 h. The in vivo evaluation in rabbits indicated that the drug-loaded CMCS hydrogels were nontoxic to the cornea and were gradually biodegraded in the eyes. Furthermore, the drug-loaded CMCS hydrogels effectively inhibited conjunctival scarring after glaucoma filtration surgery and controlled postoperative intraocular pressure (IOP).

CONCLUSION

the drug-loaded CMCS hydrogels provide a great opportunity to increase the therapeutic efficacy of glaucoma filtration surgery.

A new method of harvesting descemet membrane-endothelium complex approaching from the suprachoroidal space for descemet membrane endothelial keratoplasty: an experimental animal study

PURPOSE

To report the study in rabbits of a new method of harvesting Descemet membrane-endothelium complex approaching from the suprachoroidal space for Descemet membrane endothelial keratoplasty.

MATERIALS AND METHODS

Twenty-four eyes of 12 rabbits were used for microscopic analysis, whereas 24 eyes of 12 cats were used for gross photographic analysis. The enucleated eyeballs of the rabbits and cats were incised 360 degrees circumferentially along the equator. Manual separation was performed between the sclera and the underlying connective tissue approaching from the suprachoroidal space in the direction of the central cornea step by step in spiral pattern. After complete separation of the stroma from the Descemet membrane-endothelium-iris complex, it was excised from the globe at the outside of the iris root. The synthetic carrier (soft contact lens) was laid down on the punch block, and then the excised complex was brought over the carrier with the endothelium-iris side upward. Two steps of down punch for the designed graft size were performed. The harvested complexes were processed for vital stains and were evaluated through photography taken under a light microscope and gross close-up. The endothelial cell loss rates were calculated by a computer software.

RESULTS

The overall harvest success rate was 89.6% (43 of 48). The overall structural cell loss rate was 1.83 +/- 2.34 by microscopic analysis and 4.68% +/- 1.68% by gross photographic analysis.

CONCLUSION

The new method of en bloc harvesting Descemet membrane-endothelium complex approaching from the suprachoroidal space could provide minimal damage to the endothelium during harvesting, and it can be carried and passed through an injector.

Clinical and histopathologic features of failed descemet stripping automated endothelial keratoplasty grafts

PURPOSE

To study the histopathologic features of Descemet stripping automated endothelial keratoplasty (DSAEK) grafts removed after graft failure and to correlate with relevant clinical features.

METHODS

Retrospective study of 8 cases in 7 patients who experienced DSAEK graft failure during the surgeons' learning phase. Perioperative clinical findings were correlated with pathologic findings of the explanted graft specimens. Imaging software was used to measure the central and peripheral thickness of each graft.

RESULTS

Graft failure occurred in association with graft detachment or excessive surgical manipulation. In 4 cases, the donor tissue detached, including 2 cases with routes for bubble escape. In 3 cases, the graft remained attached but failed to clear. The mean preoperative DSAEK button thickness was 205 +/- 61.8 microm. Average death to preservation time was 8 hours 47 minutes, and average preservation to surgery time was 2 days 22 hours. By light microscopy, explanted donor tissue showed varying degrees of keratocyte degeneration and marked endothelial cell loss. Two specimens with bubble escape had less endothelial loss, and 1 specimen showed epithelial ingrowth at the interface. Repeat keratoplasty (5 DSAEK, 2 penetrating keratoplasty) was successful in 6 of 7 cases.

CONCLUSIONS

This series correlates factors that may play a role in DSAEK failure with histopathologic features of explanted DSAEK lenticules. Marked endothelial loss was common in cases with surgical trauma but was less in cases with bubble escape. One specimen showed an epithelial membrane on the stromal interface. Outcomes of repeat DSAEK in these patients seem promising.

Descemet's stripping endothelial keratoplasty: safety and outcomes: a report by the American Academy of Ophthalmology

OBJECTIVE

To review the published literature on safety and outcomes of Descemet's stripping endothelial keratoplasty (DSEK) for the surgical treatment of endothelial diseases of the cornea.

DESIGN

Peer-reviewed literature searches were conducted in PubMed and the Cochrane Library with the most recent search in February 2009. The searches yielded 2118 citations in English-language journals. The abstracts of these articles were reviewed and 131 articles were selected for possible clinical relevance, of which 34 were determined to be relevant to the assessment objectives.

RESULTS

The most common complications from DSEK among reviewed reports included posterior graft dislocations (mean, 14%; range, 0%-82%), followed by endothelial graft rejection (mean, 10%; range, 0%-45%), primary graft failure (mean, 5%; range, 0%-29%), and iatrogenic glaucoma (mean, 3%; range, 0%-15%). Average endothelial cell loss as measured by specular microscopy ranged from 25% to 54%, with an average cell loss of 37% at 6 months, and from 24% to 61%, with an average cell loss of 42% at 12 months. The average best-corrected Snellen visual acuity (mean, 9 months; range, 3-21 months) ranged from 20/34 to 20/66. A review of postoperative refractive results found induced hyperopia ranging from 0.7 to 1.5 diopters (D; mean, 1.1 D), with minimal induced astigmatism ranging from -0.4 to 0.6 D and a mean refractive shift of 0.11 D. A review of graft survival found that clear grafts at 1 year ranged from 55% to 100% (mean, 94%).

CONCLUSIONS

The evidence reviewed is supportive of DSEK being a safe and effective treatment for endothelial diseases of the cornea. In terms of surgical risks, complication rates, graft survival (clarity), visual acuity, and endothelial cell loss, DSEK appears similar to penetrating keratoplasty (PK). It seems to be superior to PK in terms of earlier visual recovery, refractive stability, postoperative refractive outcomes, wound and suture-related complications, and intraoperative and late suprachoroidal hemorrhage risk. The most common complications of DSEK do not appear to be detrimental to the ultimate vision recovery in most cases. Long-term endothelial cell survival and the risk of late endothelial rejection are beyond the scope of this assessment.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Endothelial keratoplasty: the influence of insertion techniques and incision size on donor endothelial survival

PURPOSE

To determine the acute endothelial cell damage from trephination and tissue insertion in endothelial keratoplasty (EK) surgery. The influence of insertion technique (forceps insertion vs "pull-through" insertion) of donor tissue and incision size (3 vs 5 mm length) was assessed.

METHODS

Forty precut 8.-mm-diameter donor posterior buttons were used in this study. Thirty-five buttons were inserted through a limbal incision of either 3 or 5 mm length into the anterior chamber of cadaver eyes and then removed through an open sky technique without further trauma. Five buttons that were trephined but not inserted served as a control group. Vital dye staining and computer digitized planimetry were used to analyze the tissue and quantify the total damaged area over the entire endothelial surface. Five buttons for each of 7 insertion techniques were used. The 8 tissue groups evaluated were as follows: group 1: control group of trephination only, with no insertion; group 2: forceps with folded tissue through 5-mm incision; group 3: suture pull through of nonfolded tissue through a 5-mm incision; group 4: forceps pull through of Busin glide folded tissue through a 5-mm incision; group 5: forceps with folded tissue through a 3-mm incision; group 6: suture pull through with folded tissue through a 3-mm incision; group 7: suture pull through with nonfolded tissue through a 3-mm incision; and group 8: forceps pull through of Busin glide folded tissue through a 3-mm incision.

RESULTS

The control group demonstrated 9% +/- 2% peripheral cell damage from simple trephination of the tissue but without insertion. In the 5-mm incision surgeries, forceps insertion (group 2) caused 18% +/- 3% loss, suture pull-through insertion (group 3) caused 18% +/- 2% loss, and Busin glide pull through (group 4) caused 20% +/- 5% loss. There were no significant differences in damage between any of the 5-mm incision group techniques (P > 0.99). In the 3-mm incision surgeries, forceps insertion (group 5) caused a 30% +/- 3% loss, pull through with folded tissue (group 6) caused 30% +/- 5% loss, pull through with nonfolded tissue (group 7) caused 56% +/- 4% loss, and Busin glide pull through (group 8) caused a 28%+/- 5% loss. There was no difference in damage among the 3-mm groups (P > 0.96), with the exception of group 7 where pulling the unfolded tissue through a 3-mm incision was significantly worse than all other techniques (P < 0.001). There was significantly greater cell area damage in the 3-mm groups (36%) than in the 5-mm groups (19%) (P <0.001). Large patterns of striae with cell loss were seen in the 3-mm groups emanating from the peripheral traction site, regardless of whether the traction to pull the tissue through the incision and into the chamber was generated by a suture or cross-chamber forceps. Direct forceps insertion caused circular patterns of injury at the tip compression site regardless of incision size, but this damage was multiplied and exacerbated by insertion through a smaller incision.

CONCLUSIONS

Smaller size (3 mm) incisions for EK surgery result in greater acute endothelial area damage than larger size (5 mm) incisions. Pull-through insertion techniques through a 5-mm incision seem equivalent in the amount of induced area damage to that of forceps insertion. Compressive injury from the incision appeared less when the tissue was folded than when not folded. Insertion with any technique through a 3-mm incision resulted in larger areas of endothelial damage. All these iatrogenic death zones outside the central endothelial area would be missed clinically by standard early specular microscopy after EK surgery.

Busin Guide vs Forceps for the Insertion of the Donor Lenticule in Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To compare two insertion methods in Descemet stripping automated endothelial keratoplasty (DSAEK): Busin guide-assisted vs Forceps-assisted insertion of the corneal lenticule graft.

DESIGN

Prospective, consecutive, comparative, nonrandomized study.

METHODS

setting: Cornea clinic at the Toronto Western Hospital. study population: Sixty-three eyes of 63 consecutive patients were included. All patients underwent DSAEK for Fuchs endothelial dystrophy, pseudophakic bullous keratopathy, aphakic bullous keratopathy, failed graft, or iridocorneo endothelial syndrome. Twenty-six consecutive donor discs were inserted with the Busin guide and 37 consecutive eyes underwent forceps assisted insertion of the donor. main outcome measures: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, corneal endothelial cell loss, and postoperative complications.

RESULTS

Busin guide-assisted DSAEK group had significantly worse UCVA and lower donor endothelial cell counts preoperatively. No significant differences were noted in the intraoperative or postoperative complications. Six months following surgery, BCVA was not significantly different between groups: 20/37 in the Busin guide-assisted DASEK group vs 20/42 in the Forceps-assisted group (P = .39). Mean spherical equivalent was -0.02 diopters (D) and 0.82 D (P = .06), and mean refractive cylinder was 2.2 D and 1.31 D (P = .0006), respectively. Endothelial cell loss was significantly lower in the Busin guide-assisted DASEK group: 25% loss vs 34.3% loss in the Forceps-assisted DSAEK group. (P = .04).

CONCLUSIONS

Although visual outcomes were not different between the groups studied, Busin guide-assisted DSAEK resulted in lower percentage of endothelial cell loss compared with forceps insertion, six months following surgery.

Suture-assisted vs forceps-assisted insertion of the donor lenticula during Descemet stripping automated endothelial keratoplasty

PURPOSE

To compare a new insertion method using a suture with the standard forceps-assisted insertion of the lamellar corneal graft in Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

Interventional, comparative case series.

METHODS

DSAEK was performed on 28 consecutive eyes of 28 patients (mean age +/- standard deviation, 72.5 +/- 9.7 years; 12 males). The donor tissue was prepared using the Moria automated lamellar therapeutic keratectomy microkeratome head with a 300-mm blade depth on a Moria artificial anterior chamber (Moria, Antony, France). The central 9 mm of the recipient's Descemet membrane were stripped through a superior limbal incision. In eight consecutive unselected patients, a 10-0 monofilament suture on a long straight needle was used to insert the folded donor lenticula into the recipient's eye, whereas in the other 20 patients, a standard insertion forceps was used. During the suture insertion, an anterior chamber maintainer was used to fill the anterior chamber continuously with balanced salt solution to prevent its collapse.

RESULTS

Suture-assisted DSAEK did not differ significantly from forceps-assisted DSAEK in any of the preoperative parameters. No significant differences were noted in the intraoperative or postoperative complications. Six months after surgery, there were no significant differences in endothelial cell counts (1804 vs 1935 cells/mm(2), respectively), visual acuity (20/40 vs 20/36, respectively), or refraction (spherical equivalent, 0.93 vs 1.05 diopters, respectively).

CONCLUSIONS

Suture-assisted DSAEK is a valid alternative to forceps insertion; however, it does not seem to offer a significant advantage.