Abstract
Purpose
To report the outcomes of DSAEK surgery performed in pediatric patients.
Design
Noncomparative interventional case series.
Subjects and methods
All pediatric patients (age up to 16 years) undergoing Descemet automated stripping endothelial keratoplasty (DSAEK) at our Institution since January 2008 have been enrolled in a prospective study. A standard DSAEK, involving delivery of an 8.5–9.5 mm graft by Busin glide, was performed under general anesthesia in 19 eyes of 11 pediatric patients (congenital hereditary endothelial dystrophy n = 13; congenital glaucoma n = 2; posterior polymorphous dystrophy n = 2, and failed penetrating keratoplasty n = 2). Slit-lamp examination, refraction and visual acuity as well as endothelial cell density were evaluated preoperatively as well as 1, 3, 6, 12, and 18 months postoperatively.
Results
All surgical procedures were uneventful. Graft detachment occurred in 4 cases and was managed successfully with repeat air injection. All corneas cleared within a week from surgery. Follow-up was 3–18 months. At last follow-up examination, best-corrected visual acuity (BCVA) was better than 20/40 in 8 of the 13 cases of patients old enough to assess vision. A graft rejection episode was seen in 1 case within 3 months from surgery but was reverted with steroidal treatment. No graft failures were observed.
Conclusions
DSAEK is an appropriate surgical intervention for children with corneal endothelial failure. In contrast to penetrating keratoplasty (PK), DSAEK is performed under “closed system” conditions, thus minimizing intraoperative risks. Finally, healing is much faster than with PK and all sutures can be removed within 2–4 weeks from surgery, thus allowing fast visual recovery and prompt starting of amblyopia treatment.
Keywords: DSAEK, Corneal endothelial failure, Pediatric patients
Introduction
Corneal endothelial failure in pediatric age group may be secondary to many causes, including corneal dystrophies,1,2 trauma, and congenital glaucoma.3 Loss of corneal transparency by any of these etiologies causes visual deprivation and long-term changes in the central nervous system.4
Until recent times penetrating keratoplasty (PK) was the gold standard for the treatment of endothelial failure in children. However, open-sky surgery like PK is made difficult particularly in children by the high vitreous pressure and the low scleral rigidity of these eyes. In addition, especially in older children, sutures have to stay in place for several months, thus requiring a rather long time for visual rehabilitation, while exposing them to possible late suture-related complications.4
Descemet stripping automated endothelial keratoplasty (DSAEK) is now the standard procedure for the treatment of corneal endothelial dysfunction in adults,5 and its use in the pediatric age group has been described in sporadic cases, as well as in a series of eyes with congenital hereditary endothelial dystrophy (CHED).5,7–10 We report here the outcomes of DSAEK performed at our Institution in 19 eyes with endothelial failure of different etiology.
Subjects and methods
We reviewed the medical records of all pediatric patients who underwent DSAEK at our institution from January 2007 to January 2012.
All patients or legally responsible care takers provided informed consent for the procedures performed. Analysis of the data extracted from the medical records was performed using a standard spreadsheet program. A complete ophthalmological examination, including slitlamp examination, visual acuity and manifest refraction, applanation tonometry, ocular motility, and funduscopy, was performed preoperatively in all patients when possible and appropriate. Visual acuity was measured by Snellen chart or assessment of fixation patterns in infants. Follow-up examinations were not possible at regular intervals at our institution, as most patients were referred. However, each patient was seen at our facility at least once after suture removal, and additional information was retrieved from the referring ophthalmologists.
Surgical technique
Surgery was performed using general anesthesia. The surgeon sat at the 12-o’clock position in all cases. DSAEK was performed according to the standard technique described previously and illustrated in Fig. 1.11 Descemet membrane could not be identified in infants (age < 12 months) and therefore was not stripped in these eyes. In all phakic eyes (n = 16) the incisions sites were shifted 1 mm superiorly from the standard 3 and 9 o’clock position, as shown in Fig. 1, parts b and c. This was done to protect the crystalline lens from accidental trauma with the instrument, while performing the pull through maneuver for the insertion of the graft, which was 8.5–9.5 mm in diameter.10 In the 3 aphakic eyes venting incisions were used to drain fluid from the interface while the air tamponade was taking place.
Figure 1.
DSAEK standard technique. The procedure includes: Scoring and stripping of the Descemet membrane using a 25-gauge bent needle (part a); bimanual DSAEK graft delivery under continuous irrigation through incisions shifted superiorly by 1 mm to avoid contact with the crystalline lens (parts b and c); complete air fill at the end of the procedure to tamponade the graft and secure attachment to the posterior corneal surface after air-tight suturing of all incisions, including the side entries (part d).
Postoperatively, patients were instructed to lie supine for 2 h, when possible. All patients were examined 2 h after surgery at the slitlamp or again using the operating microscope, and some air was removed when the air level failed to lie above the inferior peripheral iridotomy by this time.
Patients were given topical tobramycin, 0.3%, and dexamethasone, 0.1%, suspension (TobraDex; Alcon, Fort Worth, Texas) combination therapy every 2 h after surgery; this was reduced as clinically indicated throughout the postoperative period. All patients were seen at days 1 and 2, as well as week 1 after surgery. Later follow-up examinations were scheduled at months 1, 3, 6 and 12, and were performed elsewhere for all patients referred from other countries.
Results
Nineteen eyes of 11 patients 16-year old or younger (7 were males and 4 females) who underwent DSAEK at our institution were identified. Patients’ age ranged from 6 months to 16 years. The average follow-up in this series was 14.5 months (range 3–48 months). Causes of endothelial decompensation included: CHED, Fig. 2 part a (n = 13); posterior polymorphous dystrophy, Fig. 2 part c (PPD) (n = 2); multiple intervention for congenital glaucoma, Fig. 2 part e (n = 2); and failed PK, Fig. 2 part g (n = 2). Sixteen eyes had clear crystalline lens at the time of presentation, 3 eyes were aphakic. Four eyes had a history of previous ocular intervention. Table 1 summarizes the demographics of population.
Figure 2.
Preoperative and postoperative slit-lamp pictures of eyes undergoing DSAEK for various indications: CHED (parts a and b), PPD (parts c and d), congenital glaucoma (parts e and f) and failed PK (parts g and h).
Table 1.
Demographic data.
| Patient | Eye | Age/sex | Diagnosis | Country | Lens status |
|---|---|---|---|---|---|
| 1 | OD | 6 m/F | CHED | Abroad | Phakic |
| 1 | OS | 7 m/F | CHED | Abroad | Phakic |
| 2 | OD | 6 m/M | CHED | Abroad | Phakic |
| 2 | OS | 7 m/M | CHED | Abroad | Phakic |
| 3 | OD | 8 m/M | CHED | Abroad | Phakic |
| 3 | OS | 9 m/M | CHED | Abroad | Phakic |
| 4 | OD | 7 y/M | CHED | Abroad | Phakic |
| 5 | OD | 7 y/F | CHED | Abroad | Phakic |
| 5 | OS | 7 y/F | CHED | Abroad | Phakic |
| 6 | OD | 9 y/M | CHED | Abroad | Phakic |
| 6 | OS | 10 y/M | CHED | Abroad | Phakic |
| 7 | OD | 16 y/F | CHED | Italy | Phakic |
| 7 | OS | 16 y/F | CHED | Italy | Phakic |
| 8 | OS | 12 y/F | PPD | Italy | Phakic |
| 8 | OD | 14 y/F | PPD | Italy | Phakic |
| 9 | OD | 15 y/M | Buphthalmus | Italy | Aphakic |
| 9 | OS | 15 y/M | Buphthalmus | Italy | Aphakic |
| 10 | OD | 13 y/M | Failed PK | Italy | Phakic |
| 11 | OS | 14 y/M | Failed PK | Italy | Aphakic |
Abbreviations: m = months; y = years; M = male; F = female.
All surgeries were uneventful. No pupillary block was observed. Graft dislocation occurred in 4 eyes (all infantile) within the first two postoperative days, and was managed successfully in all eyes by re-bubbling under general anesthesia.
All corneas cleared by 1 week postoperatively and remained so for the whole period of follow-up (Fig. 2, parts b, d, f, and h). The only late complication observed was an immunologic rejection episode, easily reverted with topical and systemic steroids. No lenticular opacities were seen postoperatively in any eye.
The outcomes of DSAEK in our pediatric population is summarized in Table 2.
Table 2.
DSAEK outcomes in pediatric population.
| Patient | Eye | Preop. BCVA | Graft size (mm) | Postop. BCVA | Refraction | F/U (months) | ECL at last F/U |
|---|---|---|---|---|---|---|---|
| 1 | OD | No FF | 8.5 | FF | FF | 9 | NA |
| 1 | OD | No FF | 8.5 | FF | FF | 9 | NA |
| 2 | OD | FF | 8.5 | FF | FF | 3 | NA |
| 2 | OS | FF | 8.5 | FF | FF | 4 | NA |
| 3 | OD | FF | 8.5 | FF | FF | 4 | NA |
| 3 | OS | FF | 8.5 | FF | FF | 3 | NA |
| 4 | OD | 20/200 | 9.0 | 20/25 | +7.0/+1.5 × 80 | 48 | 19% |
| 5 | OD | 20/200 | 9.0 | 20/40 | +2.0/−0.5 × 90 | 18 | 43.0% |
| 5 | OS | CF | 9.0 | 20/70 | +2.0/−3.0 × 80 | 24 | 25.9% |
| 6 | OD | 20/200 | 9.0 | 20/25 | +7.0/+1.5 × 80 | 18 | 29.7% |
| 6 | OS | CF | 9.0 | 20/27.5 | +6.0/+0.5 × 90 | 9 | 37.5% |
| 7 | OD | 20/100 | 9.0 | 20/25 | +1.5/−2.0 × 60 | 24 | 30.5% |
| 7 | OS | 20/70 | 9.0 | 20/22.5 | +0.5/−1.0 × 90 | 30 | 34.8% |
| 8 | OS | 20/100 | 9.0 | 20/20 | −1.25 × 15 | 24 | 28.2% |
| 8 | OD | 20/100 | 9.0 | 20/22.5 | −0.25/−0.5 × 180 | 12 | 36.2% |
| 9 | OD | <20/200 | 9.5 | 20/200 | +10 sphere | 18 | 53% |
| 9 | OS | <20/200 | 9.5 | 20/200 | +10 sphere | 12 | 49.7% |
| 10 | OD | HM | 9.0 | 20/100 | −4.0/−1.0 × 20 | 3 | 36.1% |
| 11 | OS | 20/100 | 9.0 | 20/70 | +10 sphere | 12 | 36.2% |
Abbreviations: BCVA = best-corrected visual acuity; CF = count fingers; HM = hand motion; ECL = endothelial cell loss; FF = fix and follow; F/U = follow-up; NA = not available.
All 6 eyes of the 3 infants included in this series could fix and follow as early as 1 week after surgery, whereas 2 of the 6 eyes could not preoperatively. In elder children, whose visual acuity could be assessed by means of Snellen charts, best-corrected visual acuity (BCVA) improved to 20/40 or better in 8 of 13 eyes (61.5%), of which 3 eyes (23.1%) reached 20/20 and 2 eyes 20/25 vision. Reasons for vision worse than 20/40 were glaucomatous damage (n = 2), amblyopia (n = 3).
Postoperative refractive astigmatism was within 3 Diopters (D) in all cases (range from 0.5 to 3 D).
Endothelial cell density could be evaluated in 13 eyes. At the time of this review, the average endothelial cell loss from the cell count obtained at the eye bank was 35% (range from 19% to 53%).
Discussion
Penetrating keratoplasty in children, especially infants, is a challenging task. Low scleral rigidity and high intraoperative vitreous pressure increase the surgical difficulty and may lead to vision-threatening complications, such as suprachoroidal hemorrhage. Children are difficult to examine and are more prone to trauma3 and infection as well as immunologic allograft rejection. All of these factors may contribute to the high incidence of graft failure reported after pediatric PK.12–14
DSAEK offers several advantages over PK in general, but also in particular for the treatment of endothelial failure in pediatric age. It is performed under “closed system” conditions and therefore the risk of intraoperative complications is minimized.10 The small corneal incision required for DSAEK is less likely to dehisce, thus making this procedure safer than PK especially in children, who are more exposed to trauma than the adult population.15 Also, DSAEK sutures can be completely removed much earlier than after PK, thus allowing prompt treatment of amblyopia and more rapid visual recovery.16
Only few case reports of DSAEK in pediatric age have been published to date. Two reports concerned DSAEK in CHED. In one of these cases DSAEK was converted into PK due to poor visualization.7 The other article reported a successful DSAEK in a 10 years old boy, whose vision did not improve substantially due to amblyopia.17 More recently, several children together with adults were included in a series of DSAEK procedures performed for CHED.10 Successful DSAEK was also reported in one child with bullous keratopathy.6,8 To our knowledge this is the first series to report DSAEK performed for various indications exclusively in pediatric age.
In our study all grafts cleared within 1 week and remained so for an average follow-up time of over 1 year. Instead, graft failure after PK is reported in a high percentage of patients, ranging from 18.4% to almost 50% with a follow-up period up to 2 years.12,18–23
The most common post-PK complications possibly leading to graft failure in children are infection, immunologic rejection and secondary glaucoma.
Infection may occur in up to 50% of children undergoing PK and is usually related to the presence of sutures.13 Instead, infections were not seen in our series, probably because all sutures were removed as early as 2 weeks postoperatively.
Endothelial immune rejection is usually irreversible in children and is therefore one of the main causes for graft failure.3 Yang et al.24 observed graft rejection to be the most frequent cause for graft failure in their series (25%), with 48% of the rejection episodes involving the first graft. Rejection was reversible in only 28% of episodes, showing a much lower reversal rate in pediatric grafts compared to that of 50–78% in adult grafts.25 In the series by Comer et al.26 53% of the rejection episodes were not reversible and resulted in failure. Vajpayee et al.27 also noted rejection in 22.5% of cases with 55% of them not being reversible, and all of these children had reported late for management. Seventeen of 19 grafts with rejection failed in the series reported by Cowden.22 Stulting et al.20 reported 11% of graft failures to be related to allograft rejections; whereas more than 50% of the graft failures in the series by Dana et al.21 were attributed to graft rejection. In contrast to this data, we observed only 1 case of immunologic rejection in our series of patients, and it was easily reversed with steroidal treatment with a final visual acuity of 20/20.
Finally, glaucoma has been reported in up to 16% of post-PK pediatric patients.12,18,19 Although most of the eyes included in our series presented normal anterior segment anatomy, glaucoma was present in 3 of them (congenital in 2 acquired in 1). After DSAEK, none of our patients newly developed glaucoma or required intraocular pressure (IOP) lowering medications additional to the ones used preoperatively.
The most common postoperative complication in our DSAEK series was graft detachment, which occurred in 4 infants of the total 19 eyes (21%). This complication is obviously unique to DSAEK, but can be easily managed successfully by simple air injection, as it was in all 4 cases of our series.
Also visual results obtained after DSAEK in children compare favorably with those of PK performed in the same age group.12,18–23 Table 3 summarizes the visual outcomes of pediatric PK in different studies published to date. Main factors affecting post-PK visual acuity in children include age at the time of surgery and indication for surgery. Elder children and acquired corneal disease (including keratoconus) have a better visual prognosis than infants and congenital corneal disorders.23 However, in general, BCVA of 20/40 or better is seldom achieved, despite PK being often performed at an early age. As with adults, also children usually experience a prolonged time of visual impairment after PK, due to corneal distortion secondary to the presence of sutures. In addition, high-degree astigmatism, often of the irregular type, may persist in up to 21% of eyes even after suture removal is completed.28 Under these conditions, treatment of amblyopia may be impossible and therefore visual acuity would not improve. In DSAEK the few sutures required can be removed within 2 weeks postoperatively. In bilateral cases, this is usually done at the time of the second eye undergoing DSAEK. The optical correction of the residual refractive error can be prescribed as early as one month postoperatively and amblyopia treatment started. In addition, as opposed to PK, spectacle correction is possible in all cases, as the final astigmatism is of the regular type and low in absolute value. In our series, we did not observe any post-DSAEK astigmatic error higher than 3.0 D. As a result, 8 of 13 eyes (61.5%) of our verbal patients enjoyed 20/40 BCVA or better, with 3 of 13 eyes (23.1%) seeing 20/20.
Table 3.
Literature review of graft failure and visual outcomes of PK in children.
| Paper | Age criteria | Number of eyes | Postoperative complications | Graft failure |
BCVA |
||
|---|---|---|---|---|---|---|---|
| F/U 12 m | F/U 24 m | ⩾20/40 | ⩾20/200 | ||||
| Sharma et al.18 | ⩽15 y | 168 | Infection 28.6%. 2ry glaucoma 16.01%. Graft rejection 10.11% | 13% | 23% | NA | 30.1% |
| Al Ghamdi et al.12 | ⩽12 y | 165 | Infection 26.6%. Glaucoma 33.3% (new or pre-existing). Graft rejection 8.48% | 36.3% | 49.1% | 4.8% | 19.4% |
| Aasuri et al.19 | ⩽14y | 154 | Infection 26.9%. 2ry glaucoma 13.4%. Graft rejection 42.3% | NA | 42.3% | ⩾20/50 23.9% | 43.8% |
| Stulting et al.20 | ⩽15 y | 107 | NA | 44% | NA | NA | NA |
| Dana et al.21 | ⩽12 y | 131 | Infection 8%. Secondary glaucoma 29%. Graft rejection 31% | 20% | 33% | NA | 33% |
| Cowden 22 | ⩽15 y | 57 | Graft rejection 33.3% | NA | 46% | NA | NA |
| Patel et al.23 | ⩽15 y | 58 | Graft rejection 10%. Primary failure 4% | 18% | NA | ⩾20/30 38% | ⩾20/60 60% |
It is certainly difficult to compare trials directly, given the differences in patient ages and disease severity and/or amblyopia as well as the differing proportions of patients being of verbal age and therefore able to comply with visual acuity testing.12,18–23 However, based on our experience DSAEK has proven superior to conventional PK in terms of safety and efficacy for the treatment of endothelial decompensation in the pediatric age group. If our preliminary data will be confirmed in a larger number of patients followed for a prolonged period of time, DSAEK surgery will soon replace conventional PK also in the pediatric population.
Financial disclosure
Massimo Busin receives travel expenses reimbursement and Royalties from Moria (Antony, France). Silvana Madi and Paolo Santorum have no financial interest to disclose.
Footnotes
Presented in part at the Annual Meeting of the American Society for Cataract and Refractive Surgery, San Diego, California, March 25–29, 2011.
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