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Outcomes of Descemet stripping endothelial keratoplasty in cases of corneal endothelial dysfunction
Dubbaka Srujana, Nabaratna Bista, Mohini Agrawal
Department of Ophthalmology, Armed Forces Medical College, Pune, Maharashtra, India
|Date of Submission||24-Apr-2021|
|Date of Decision||02-Nov-2021|
|Date of Acceptance||06-Nov-2021|
|Date of Web Publication||03-Aug-2022|
Department of Ophthalmology, Armed Forces Medical College, Pune - 411 040, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
BACKGROUND: Automated microkeratome is commonly used to get donor lenticules for Descemet stripping endothelial keratoplasty (DSEK); however, manual dissection of donor lenticules is also being done with good outcomes.
AIM: The aim of this study was to describe the results of manual DSEK performed in cases of corneal endothelial dysfunction caused due to pseudophakic bullous keratopathy, iridocorneal endothelial syndrome, and postpenetrating keratoplasty graft failure.
MATERIALS AND METHODS: This was a retrospective observational study. The medical records of all patients with corneal decompensation who underwent DSEK at a tertiary care center performed by the same surgeon were reviewed. A standard DSEK with manually dissected donor lenticules was performed in all cases with the exception of the Descemet membrane not being removed in two cases. A comprehensive ophthalmic examination was performed preoperatively and at each postoperative visit in all patients.
RESULTS: Eight eyes of seven patients (four males and three females) were included. The mean age was 64.8 years (range, 49–74 years). The average follow-up was 10.9 months (range, 5–22 months). There was one case of primary graft failure which was managed by repeat DSEK. In the rest, corneas remained clear at the last follow-up. No rebubbling was done as none of the cases showed graft detachment. The preoperative best-corrected visual acuity (BCVA) was 20/2000 or less, and postoperatively, BCVA attained was 20/30 in four eyes and one eye achieved 20/80.
CONCLUSIONS: Manual DSEK performed in eyes with corneal decompensation allowed rapid restoration of corneal clarity while minimizing intraoperative and postoperative complications.
Keywords: Donor lenticule, endothelial keratoplasty, manual dissection, pseudophakic bullous keratopathy
|How to cite this URL:|
Srujana D, Bista N, Agrawal M. Outcomes of Descemet stripping endothelial keratoplasty in cases of corneal endothelial dysfunction. Oman J Ophthalmol [Epub ahead of print] [cited 2022 Sep 29]. Available from: https://www.ojoonline.org/preprintarticle.asp?id=353266
| Introduction|| |
In adults, corneal decompensation due to endothelial dysfunction with the resultant edema is seen most commonly in pseudophakic bullous keratopathy, the other causes being Fuchs' corneal dystrophy, post penetrating keratoplasty (PK) graft failure, and iridocorneal endothelial (ICE) syndrome. Earlier, these cases were managed with full-thickness PK; however, there were many drawbacks in the form of postoperative astigmatism, slow visual stabilization, graft rejection, and risk of dehiscence at the host-graft interface, in addition to intraoperative complications of open sky procedure. To overcome these difficulties, various posterior lamellar keratoplasty techniques have been introduced, of which Descemet stripping endothelial keratoplasty (DSEK) has gained tremendous popularity. In DSEK, the diseased endothelium along with Descemet membrane is selectively replaced by a healthy donor lenticule consisting of endothelium, Descemet membrane, and posterior stroma. The donor lenticule is apposed against the back of the recipient cornea with an air bubble without the use of sutures. As compared to PK, DSEK offers many advantages such as rapid visual recovery, no suture-related sequelae, better corneal structural integrity, and innervation. The donor lenticule dissection for DSEK is most commonly done using automated microkeratome to obtain lenticule of predictable thickness. At centers without automated microkeratome, donor lenticules are obtained by manual dissection or by using precut tissues from nearest eye bank.
There is no published literature on manual DSEK from this part of the country. In this study, we report outcomes of DSEK using donor lenticules obtained by manual dissection done for consecutive cases of corneal decompensation in PBK, post-PK graft failure, and ICE syndrome.
| Materials and Methods|| |
A retrospective study was done on data containing all the operative and follow-up details of consecutive cases with manual DSEK managed by a single surgeon (standard deviation [SD]) between 2018 and 2020. Eyes with a preoperative diagnosis of corneal decompensation were selected for analysis regardless of the presence of comorbidities, including glaucoma and macular edema [Table 1]. The outcome measures were taken as incidence of intraoperative complications, postoperative complications (including interface fluid, dislocation, raised intraocular pressure (IOP), primary graft failure, rebubbling, and rejection), best-corrected visual acuity (BCVA), donor lenticule thickness, host cornea thickness, and graft survival. Informed consent was obtained from the patients for their medical records to be used. The study was approved by the Institute's Ethics Committee and adhered to the tenets of the Declaration of Helsinki.
|Table 1: Patient demographics, prior ocular surgeries, and preoperative assessment|
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The mean preoperative donor endothelial cell density was 2519.8 cells/mm2 ± 258.9 (range, 2083–2849 cell/mm2). Donor lenticule was prepared on artificial anterior chamber using the Melles technique of deep manual dissection. Donor insertion was performed using Busin glide (Moria USA, Doylestown, PA) through a clear corneal tunnel incision of 4 mm. In one case (case 6) of ICE syndrome with immature senile cataract, DSEK triple procedure (DSEK + phacoemulsification + posterior chamber intraocular lens implantation) was done. Follow-up was done as per our center's standard DSEK protocol – patients were reviewed at 1 day, 3 days, 1 week, 1 month, 3 months, 6 months, and thereafter 3 monthly. Postoperative antibiotic steroid drops were started 2 hourly initially and tapered slowly over 6 months with a maintenance regimen of dexamethasone twice daily from 6 months onward.
At each routine visit, the following measurements were taken: BCVA by the Snellen chart, IOP by noncontact tonometry (Topcon CT-800, Topcon Corporation, Tokyo). Cornea scan of Cirrus HD OCT 5000 (Carl Zeiss Meditec Inc, CA) was used to assess the overall integrity of the donor lenticule, its thickness, host stromal thickness, interface fluid, dislocation, rejection, and failure. Time to graft failure was taken as the first follow-up visit at which the cornea was irreversibly decompensated.
Descriptive statistics for continuous variables were reported as mean ± SD and range. Statistical analysis was performed using SPSS software, version 17.0 (SPSS Inc., Released 2008, Chicago, IL, USA).
| Results|| |
Eight eyes of seven patients with a mean age of 64.8 years (range, 49–74 years) were included. There were five cases of PBK, one post-PK graft failure, one ICE syndrome, and one failed DSEK. Preoperative BCVA was 20/2000 or less with an average preoperative central corneal thickness of 757.4 μ±92.4 (range, 640–924) by cornea scan of OCT [Figure 1]. Additional procedure of phacoemulsification with posterior chamber implantation was done in one case of ICE syndrome [Figure 2]. Nonstripping DSEK (nDSEK), wherein host Descemet membrane is not removed, is performed in case 2 (post-PK graft failure) and case 7 (PBK). Mean follow-up after the DSEK surgery was 10.9 months (range, 5–22 months). The mean donor lenticule thickness at day-1 postoperative and last follow-up is 215.8 μ ± 33.8 (range, 176–288) and 155.5 μ ± 29.9 (range, 117–194), respectively. The preoperative, intraoperative, and postoperative details for each graft are shown in [Table 1], [Table 2], [Table 3], respectively.
|Figure 1: Clinical photographs (a-c) and HD cornea OCT (d-f) of preop, day 1 postoperative and at 20-month follow-up, respectively, of pseudophakic bullous keratopathy (case 1)|
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|Figure 2: Clinical photographs (a-c) and HD cornea OCT (d-f) of preoperatie, day 1 postoperative and at 6-month follow-up, respectively, of iridocorneal endothelial syndrome (case 6)|
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There was perforation of donor cornea during manual dissection of donor lenticule for case 5 while trying to achieve thin donor lenticule with curved lamellar dissector, for which donor cornea was changed with a new one. In two grafts (case 3 and case 4), there was traumatic graft insertion with donor-iris contact and excessive donor lenticule manipulation.
Interface fluid was noticed in one graft [case 7, [Figure 3]], which resolved on its own within the 1st week without requirement of rebubbling. There were no dislocated grafts. Primary graft failure was noted in one graft (12.5%, case 4). Raised IOP occurred in four grafts on day 1 postoperative which was managed with oral Diamox 250 mg TDS for 2 days. Case 5 had preexisting secondary glaucoma in which IOP was controlled with eyedrop timolol + brimonidine combination preoperatively, and the same was continued postoperatively.
|Figure 3: Interface fluid (white arrow) on day 1 postoperative in case 7|
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[Figure 4] and [Figure 5] show donor lenticule thickness and host corneal thickness, respectively, for the eight grafts at day-1 postoperative and last follow-up. BCVA of 20/30–20/80 was achieved within the first 3 months postoperatively in five of eight grafts. Vision did not improve in two cases despite functioning graft due to refractory cystoid macular edema in case 3 and preexisting glaucomatous damage in case 5. In one case, primary graft failure was noted, probably attributed to excessive tissue manipulation, which underwent repeat DSEK (case 8) with good anatomical and visual outcomes.
|Figure 4: Donor lenticule thickness on day 1 postoperative and at last follow-up|
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|Figure 5: Host cornea thickness on day 1 postoperative and at last follow-up|
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One out of eight grafts showed primary graft failure, the rest showed clear cornea at the last follow-up, and none of them showed any rejection episodes/secondary graft failure. An interesting fact noted in the case with failed graft was that despite primary graft failure, there was a definite reduction in host corneal thickness, resolution of bullae, and relief from pain in the follow-up visits; however, there was persistent microcystic edema, few DM folds in the stroma of donor lenticule at 5-month follow-up.
| Discussion|| |
As compared to conventional PK, DSEK gives excellent anatomical and visual outcomes in corneal endothelial dysfunction disorders such as PBK, Fuchs' corneal dystrophy, post-PK graft decompensation, and ICE syndrome.,, Availability of automated microkeratome with single-use microkeratome blades for donor lenticule dissection is a limiting factor for this increasingly popular procedure performed by corneal surgeons worldwide. However, with surgical experience, this can be circumvented with manual dissection of donor corneas to give good donor lenticules with a regular stromal surface. A study of DSEK cases with manual dissection of donor corneas reported a 3.5% incidence of donor dissection and insertion-related complications, of which 1.4% cases required replacement with new donor buttons. Another study reported a 4.4% incidence of donor cornea perforation during manual dissection. In our limited case series, we had one donor corneal perforation during manual dissection of donor corneas which had to be replaced with another donor cornea and we did not encounter any donor lenticule insertion-related complications such as reverse unfolding or donor tissue extrusion.
At 6 months after transplant, Price et al. reported BCVA of 20/40 or better in 69% of the eyes without documented retinal problems or amblyopia with manually dissected donor lenticules, as compared to 79% with microkeratome-dissected donor tissue. In our series, out of six cases without posterior segmented related problems, four (66.7%) achieved BCVA of 20/30 at the last follow-up. In one case of post-PK, DSEK BCVA of 20/80 was achieved.
In the immediate postoperative period, the most commonly reported complication is donor lenticule dislocation.,, An incidence of 50% was reported by Price et al. in their series of first 10 eyes, which was reduced to 6% in the last 64 cases in their study of 200 DSEK cases. Various techniques have been developed to reduce this complication such as completely removing entrapped fluid from the interface by massaging and making fenestrations in the host cornea. Donor lenticule detachment is managed by intracameral reinjection of air also called rebubbling. In our series, none of the cases had graft dislocation; however, interface fluid was noted on day 1 postoperative in one case [case 7, [Figure 3]] which spontaneously resolved without the need for rebubbling.
Another complication after DSEK is primary graft failure which is attributed to poor donor cornea or excessive tissue manipulation during surgery. The rates of primary graft failure reported in various studies ranged from 0% to 29%.,, In our study, there was traumatic insertion with excessive donor lenticule manipulation in two cases, of which one showed primary graft failure (case 4) and the other showed delayed visual recovery (case 3). Despite primary graft failure in case 4, interestingly, it was noted that there was a definite decrease in host corneal thickness over a follow-up period of 5 months [Figure 5]; however, there was the persistence of microcystic and stromal edema. Graft rejection is another cause of graft failure with reported rates of 7.3% to 8.5%,,, and most of the cases occur between 8 and 34 months postoperatively. There was no case of graft rejection in our series with follow-up ranging from 5 to 22 months.
| Conclusions|| |
DSEK is a safe and effective procedure for cases of corneal endothelial dysfunction. Manual dissection of donor lenticules is a good alternative to automated microkeratome. Learning curve of manual dissection can be definitely reduced with simultaneous wet laboratory practice on nonsurgical grade donor corneas. Intra- and postoperative complications could be minimized by adhering to the techniques evolved over the past decade.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]