New Graft Insertion Device for Descemet Stripping Automated Endothelial Keratoplasty

Descemet stripping automated endothelial keratoplasty via a frown incision

PURPOSE

To assess the outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) via a sclerocorneal frown incision.

STUDY DESIGN

Retrospective comparative study.

METHODS

The outcomes of Descement stripping endothelial keratoplasty (DSAEK) were retrospectively compared between 36 patients (36 eyes) who underwent surgery via a 3.8-mm frown incision (frown incision group) and 20 patients (20 eyes) who underwent surgery via a 4.6-mm straight incision (straight incision group). In all patients, an NS Endo-Inserter was used as the graft inserter and the incision for a frown incision was via the superior sclerocorneal site and for the straight incision via the temporal cornea. DSAEK was performed by the standard technique, except for the incision. At 1 year after surgery, the two groups were compared with respect to the visual acuity, decrease of corneal endothelial cell density, the severity of corneal astigmatism (diopters), the number of sutures for wound closure, and intraoperative/postoperative complications.

RESULTS

There was no significant difference between the two groups in terms of postoperative visual acuity, corneal astigmatism, and intraoperative/postoperative complications one year after surgery. On the other hand, the number of sutures required for wound closure was 1.13 ± 0.42 in the frown incision group, whereas in the straight incision group, it was 3.20 ± 0.40, showing a significant difference (P<0.001). In addition, there was no decreased corneal endothelial cell density associated with the reduction in incision width.

CONCLUSIONS

A sclerocorneal frown incision is useful for performing DSAEK with an NS Endo-Inserter as it does not affect endothelial cell loss despite its short incision width.

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.

Intraoperative optical coherence tomography-guided nanothin Descemet stripping automated endothelial keratoplasty in a patient with a remarkably thickened cornea

Purpose

To report use of intraoperative optical coherence tomography (OCT) for nanothin Descemet stripping automated endothelial keratoplasty (DSAEK) in a patient with an extremely thickened cornea due to advanced bullous keratopathy.

Observations

A 90-year-old woman with a history of multiple trabeculectomies was referred to us for treatment of advanced bullous keratopathy (1400 μm central corneal thickness). Nanothin DSAEK was planned and performed. In brief, after the removal of the loose corneal epithelium, the anterior chamber was meticulously observed using a surgical microscope and oblique light via an endoillumination probe; however, the visibility of the anterior chamber was limited because of severe corneal edema. Subsequently, a nanothin (47 μm) DSAEK graft stained with trypan blue was inserted into the anterior chamber using an NS endoinserter. Intraoperative OCT was used successfully to visualize the graft unfolding, air tamponade, and graft attachment. At 3 months postoperatively, significant corneal clearing (625 μm central corneal thickness), improvement of visual acuity (decimal 0.04), and pain relief were obtained.

Conclusions and importance

Intraoperative OCT is useful for nanothin DSAEK even when the surgical microscope view is compromised by a remarkably thickened host cornea due to advanced bullous keratopathy. As an alternative to a penetrating keratoplasty, less invasive nanothin DSAEK was successfully performed.

Clinical Evaluation of the "Lifeline Suture" Technique for DSAEK in Cases Without Posterior Capsule Using a Novel Donor Insertion Device

PURPOSE

This study investigated preliminary clinical outcomes of a suture pull-through technique for Descemet stripping automated endothelial keratoplasty (DSAEK) termed the "lifeline suture" technique using a newly developed donor inserter (NS Endo-Inserter: NSI; Hoya Co, Ltd, Tokyo, Japan) in cases of bullous keratopathy without posterior capsule.

METHODS

Six aphakic eyes without posterior capsule from 6 patients (mean age 73.8 ± 11.9 years) with bullous keratopathy were enrolled. DSAEK alone or as a vitreocorneal surgery was performed. Donor tissue was pulled into the anterior chamber using the NSI and a 9-0 polypropylene "lifeline suture" to prevent donor tissue from slipping into the vitreous cavity, which was removed at the end of surgery. Intraoperative and postoperative complications and 6-month postoperative central donor endothelial cell densities were measured and compared with preoperative values along with 6-month best-corrected visual acuity.

RESULTS

All donors were successfully loaded into the NSI and then pulled into the anterior chamber using the lifeline suture. No intraoperative complications, graft dislocation, or primary graft failures were noted. Six months postsurgery, mean endothelial cell density was 2027 ± 747 cells/mm (mean loss 27.2 ± 28.1%) and mean best-corrected visual acuity improved to 0.31 decimal (P = 0.018).

CONCLUSIONS

In this preliminary case series of bullous keratopathy without posterior capsule, DSAEK outcomes using the novel NSI donor inserter with lifeline suture were comparable or better than the results expected with conventional strategies. Thus, this technique enabled apparently safe DSAEK, preventing donor migration into the vitreous cavity while maintaining a stable anterior chamber, and is suitable for complex eyes including aphakia, lacking posterior capsule, or avitreal.

NS Endo-Inserter: A New Graft Inserter for Descemet Stripping Automated Endothelial Keratoplasty

Although Descemet stripping automated endothelial keratoplasty (DSAEK) has become widespread as a first choice for the treatment of bullous keratopathy, corneal endothelial cell loss during the early postoperative period caused by intraoperative mechanical stress to the donor endothelium remains a clinical challenge. At present, a pull-through technique is the standard procedure for graft delivery in DSAEK. However, the anterior chamber is likely to collapse during graft delivery in patients with a small eye or shallow anterior chamber, as often seen in Asian patients, leading to endothelial cell damage. To solve this problem, we developed a new device for DSAEK, known as NS Endo-Inserter, in which the graft flows into the anterior chamber in a balanced salt solution in one step. This article reviews the features of NS Endo-Inserter and the outcomes of DSAEK using this device.

Clinical Evaluation of the NS Endo-Inserter, a Novel Donor Inserter for Descemet's Stripping Automated Endothelial Keratoplasty

Purpose

This study investigated the clinical outcomes achieved with a newly developed donor inserter (NS Endo-Inserter [NSI], HOYA Co., Ltd., Tokyo, Japan) for Descemet's stripping automated endothelial keratoplasty (DSAEK) in Japanese eyes with bullous keratopathy secondary to argon laser iridotomy (BK-ALI). The NSI device utilizes pressure flow to push the DSAEK donor tissue into the anterior chamber.

Methods

Six eyes of 6 patients (1 male, 5 females; mean age, 78.5 years) with BK-ALI were enrolled. Donor tissue was pushed into the anterior chamber using the NSI. Intraoperative complications, graft dislocation, and iatrogenic primary graft failure were recorded for all eyes. Six-month postoperative central donor endothelial cell densities (ECD) were measured prospectively and compared with preoperative values, along with 6-month best corrected visual acuity (BCVA).

Results

In all cases, donor loading onto the NSI spatula and donor insertion into the anterior chamber using the NSI was smooth and successful; no intraoperative complications were noted. There were no cases of graft dislocation or IPGF. Postoperative ECD was 2,187.2 cells/mm² (mean loss, 14.8%) and mean BCVA increased from 0.27 decimal to 0.8 at 6 months.

Conclusion

In this small preliminary case series, clinical outcomes for patients with BK-ALI undergoing DSAEK using the NSI were comparable or better than those achieved with conventional DSAEK insertion techniques.

Clinical evaluation of a newly developed graft inserter (NS Endo-Inserter) for Descemet stripping automated endothelial keratoplasty

Purpose

The aim of this study was to describe the postoperative outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) performed using our newly developed graft inserter (NS Endo-Inserter) and compare the findings with those for DSAEK performed using the Busin glide.

Patients and methods

In this retrospective, case-control, institutional study, we studied the clinical outcomes of DSAEK performed using the NS Endo-Inserter (NS group, n=13) or the Busin glide (Busin group, n=10) for patients with corneal endothelial dysfunction. Clinical parameters, including the distance-corrected visual acuity (DCVA), endothelial cell (EC) loss, and intraoperative/postoperative complications, were assessed over a 6-month follow-up period.

Results

At 6 months after surgery, the mean DCVA showed no significant difference between the two groups. EC loss at 3 and 6 months after DSAEK was 9.1%±20.7% and 18.2%±22.6%, respectively, in the NS group and 44.0%±25.5% and 46.5%±23.3%, respectively, in the Busin group; differences between groups were statistically significant at both 3 and 6 months (P=0.024 and P=0.016, respectively). Anterior chamber hemorrhage was observed in one patient in the Busin group. Rebubbling after surgery was required for one eye in the Busin group. No complications were observed in the NS group.

Conclusion

Our newly developed graft inserter for DSAEK may cause significantly less EC damage than the conventional pull-through technique using the Busin glide. Our inserter permits safe endothelial graft delivery without anterior chamber collapse and can result in successful graft attachment without complications at 6 months after surgery.

Measuring Endothelial Cell Loss on DMEK Grafts After Transplantation in Human Cadaveric Whole Eyes: Description of the Technique and Pilot Study

PURPOSE

To describe a novel method for analyzing Descemet membrane endothelial keratoplasty (DMEK) graft damage after implantation into human cadaveric donor eyes and to compare results achieved by performing DMEK with a surgeon's long-established technique compared with those of an unfamiliar technique.

METHODS

Eight DMEK grafts were implanted into previously frozen human cadaveric eyes. Four grafts were implanted using a Straiko injector and tap technique familiar to the surgeon (C.S.S., 3-yr experience), and 4 grafts were implanted using the Tan EndoGlide and "donor mat device" pull-through technique new to the surgeon. After implanting a DMEK graft and attaching it to the recipient stroma with an air bubble tamponade, the corneoscleral cap was "recovered" from the cadaveric globe using standard techniques. The DMEK graft was stained with Calcein-AM. After staining, a 9.5-mm stromal "carrier button" was punched, and the carrier and graft were transferred to a microscope slide. Grafts were imaged and analyzed using FIJI trainable segmentation.

RESULTS

Donor graft characteristics were similar between both groups. Grafts implanted using the surgeon's routine technique showed an average endothelial cell loss (ECL) of 31% ± 4% (n = 3). Grafts implanted using the technique unfamiliar to the surgeon showed an average ECL of 47% ± 24%, but with a trend toward improvement (1 = 76%, 2 = 65%, 3 = 32%, 4 = 17% ECL).

CONCLUSIONS

Our proof-of-principle experiment shows that this imaging approach enables quantification of ECL caused by different instruments and surgical techniques after graft implantation. We have used this method to visualize the learning curve of 1 surgeon when learning a new surgical technique.