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| ORIGINAL ARTICLE |
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| Year : 2023 | Volume
: 16
| Issue : 1 | Page : 23-29 |
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Complications in deep anterior lamellar keratoplasty – A retrospective cross sectional interventional analysis in a large series
Shreesha Kumar Kodavoor1, Neha Rathi2, Ramamurthy Dandapani1
1 Department of Cornea and Refractive Services, The Eye Foundation Hospital, Coimbatore, Tamil Nadu, India
2 Department of Cornea, Cataract and Refractive Services, The Eye Foundation Hospital, Coimbatore, Tamil Nadu, India
| Date of Submission | 15-Mar-2022 |
| Date of Decision | 13-Apr-2022 |
| Date of Acceptance | 22-Sep-2022 |
| Date of Web Publication | 21-Feb-2023 |
Correspondence Address:
Shreesha Kumar Kodavoor
582-A, Diwan Bahadur Road, R S Puram West, Coimbatore - 641 002, Tamil Nadu
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ojo.ojo_72_22
 Abstract | | |
AIM: To analyse complications in patients managed with deep anterior lamellar keratoplasty (DALK) for diseases of anterior corneal stroma.
MATERIALS AND METHODS: This was a retrospective analysis of all the patients who underwent DALK in a tertiary care center in South India from 2010 to 2021. A total of 484 eyes in 378 patients were included in the study. Patients who underwent DALK for advanced keratoconus, keratoconus with Bowman's membrane scar, healed hydrops, macular corneal opacity, macular corneal dystrophy, granular corneal dystrophy, spheroidal degeneration, pellucid marginal degeneration, post-LASIK ectasia, descemetocele, postcollagen cross-linking aborted melt and dense scar, and postradial keratotomy were included in the study. The patients were followed up for 17.6±9.4 months(1–10years).
RESULTS: Complications noted in the surgery were intraoperatively Descemet's membrane perforation in 32 eyes (6.6%), postoperatively secondary glaucoma in 16 eyes (3.31%), cataract in 7 eyes (1.45%), suture-related complications in 5 eyes (1.03%), graft rejection in 3 eyes (0.61%), traumatic dehiscence in 2 eyes (0.41%), filamentary keratitis in 2 eyes (0.41%), interface infiltrate in 1 eye (0.21%), and recurrence of disease in 4 eyes (8.77%) out of 57 eyes with corneal dystrophy.
CONCLUSION: DALK as an alternative to penetrating keratoplasty for anterior corneal stromal diseases has proven to be better time and again. It has become an automatic choice for diseases of anterior cornea requiring keratoplasty. Complications occurring at any stage of surgery can be identified and managed effectively resulting in optimal outcome. This article compiles complications post DALK.
Keywords: Deep anterior lamellar keratoplasty, Descemet's membrane perforation, double anterior chamber, graft rejection, interface infectious keratitis
How to cite this article:
Kodavoor SK, Rathi N, Dandapani R. Complications in deep anterior lamellar keratoplasty – A retrospective cross sectional interventional analysis in a large series. Oman J Ophthalmol 2023;16:23-9 |
How to cite this URL:
Kodavoor SK, Rathi N, Dandapani R. Complications in deep anterior lamellar keratoplasty – A retrospective cross sectional interventional analysis in a large series. Oman J Ophthalmol [serial online] 2023 [cited 2023 Mar 26];16:23-9. Available from: https://www.ojoonline.org/text.asp?2023/16/1/23/370062 |
| Introduction | |  |
Deep anterior lamellar keratoplasty (DALK) is performed in diseases of anterior corneal stroma in which the pathologic corneal stroma is replaced by donor graft sparing the corneal endothelium eliminating endothelial graft rejection and reduced rates of endothelial cell count. It overcomes multiple complications associated with penetrating keratoplasty being an open globe surgery, complications such as expulsive hemorrhage and endophthalmitis. The most commonly performed surgical technique is Anwar big-bubble technique invented in 1974;[1] this technique has multiple benefits over manual stromal dissection. Indications for DALK are advanced keratoconus, pellucid marginal degeneration, progressive post-LASIK ectasia, hereditary stromal dystrophies, corneal stromal scars, infectious keratitis, and tectonic indications. Contraindications include dysfunctional endothelium and deep scars involving Descemet's membrane in the visual axis.
The purpose of this article is to evaluate the intraoperative and postoperative complications related to DALK.
| Materials and Methods | | |
The patients who had undergone DALK in a tertiary eye care hospital in South India from the period of 2010 to 2021 were retrospectively analyzed for complications after surgery. A total of 484 eyes in 378 patients were included in the study. Patients who had undergone DALK for (a) keratoconus, (b) macular corneal opacity, (c) postcollagen cross-linking aborted corneal melt, (d) hereditary stromal dystrophies, (e) corneal degeneration, (f) pellucid marginal degeneration, (g) post-LASIK ectasia, (h) descemetocele, and (i) postradial keratectomy were included in the study. [Table 1] shows indications for DALK in our study. | Table 1: Indications of deep anterior lamellar keratoplasty in our study
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Preoperative data collection included age, sex, visual acuity, ocular examination, surgical history, and anterior segment optical coherence tomography. Postoperatively, type of procedure, visual acuity, complications, and duration of follow-up were noted. Based on the type of corneal stromal disease, appropriate surgical technique of performing DALK was opted.
Most of the cases were done under peribulbar anesthesia using 5 ml 2% lignocaine and 5 ml 0.75% bupivacaine except a few which needed surgery under general anesthesia. For patients with stromal diseases not involving Descemet's membrane, big-bubble technique invented by Anwar and Teichmann was performed in which after approximately 70%-80% of host corneal trephination, a 26-gauge needle attached to a sterile air-filled 5 cc syringe is introduced into deepstroma with bevel facing downward toward central cornea. Air is then gently injected which forms a round, well-demarcated big-bubble extending to the borders or beyond borders of trephination. Trephination was performed of the same size in donor and recipient cornea in Keratoconus patients while a discrepancy of 0.25 mm was implied in all the other cases. Post this, debulking of the anterior 2/3rd of stroma is performed using crescent blade and Lim's forceps. Then, with no. 11 blade, a central bold nick is given to collapse the bubble post which viscoelastic is injected through the nick incision to keep the Descemet's away from all the manipulations. The posterior lamella was then divided into 4-5 segments and excised using Vannas' scissor to explore the smooth Descemet's. The donor corneal tissue Descemet's endothelial layer is scraped off using a Merocel sponge or a nontoothed forceps and is then placed over host cornea after thorough irrigation of host bed with saline to remove all viscoelastic substance and then secured with 16 interrupted sutures when the selected donor graft size is more than 8 mm and with 12 interrupted sutures when the donor graft size is 8 mm or less.
Manual layer-by-layer stromal dissection technique was performed in patients with healed hydrops, formation of type 2 or type 3 bubble intraoperatively, and those with descemetocele. A partial trephination of approximately 2/3rd of the total corneal thickness is performed, followed by stromal removal using a bevel-up crescent knife. Layer-by-layer stromal dissection and resection is repeated until deep stromal layer or predescemetic layer is approached. Then, donor graft is placed and secured with interrupted sutures.
Postoperatively, all the patients were started on topical antibiotics (0.5% moxifloxacin), 4 times/day for 2 weeks, topical steroids (1% prednisolone) 6 times/day for the first week and then tapered gradually, and preservative-free tear substitutes (0.5% carboxymethyl cellulose) for 6 weeks. The patients were followed at day 1, 2 weeks, 6 weeks, 6 months initially after the surgery, and then every 6 months thereafter. All the complications during and after surgery during the follow-up period were noted and appropriate corrective measures were undertaken to address the complications. The study was approved by the institutional ethics committee and adhered to the tenets of the Declaration of Helsinki.
| Results | | |
The study included 484 eyes of 378 patients, and these patients were retrospectively analyzed. Three hundred and thirty-one eyes were treated for patients with keratoconus out of which 118 eyes had keratoconus with bowman's membrane scar 197 eyes had advanced keratoconus and 27 eyes had healed hydrops with paracentral scars, 35 eyes for patients with macular corneal opacity, 29 eyes for macular corneal dystrophy, 27 eyes for granular corneal dystrophy, 18 eyes for spheroidal degeneration, 10 eyes for post-LASIK ectasia, 7 eyes for patients who had aborted corneal melt post collagen cross-linking, 6 eyes for progressive corneal ulcer with descemetocele, 6 eyes with multiple linear irregular scars post radial keratotomy, and 5 eyes for pellucid marginal degeneration. Out of 378 patients, 177 patients were male and 201 patients were female. The follow-up period ranged from 1 year to 10 years, with an average of 16 months. Demographic data, number, types of anterior corneal stromal diseases included in the study, and the follow-up period are shown in [Table 2].
Intraoperatively 31 (6.54%) eyes had Descemet's membrane perforation among which 18 eyes had perforation during layer-by-layer dissection of stroma in healed hydrops [Figure 1], 10 eyes had perforation during dissection of type 2 bubble in macular corneal opacities and 1 eye had perforation while suturing of donor graft. The following postoperative complications were noted in these 484 cases. Various causes of intraocular pressure (IOP) rise were noted in 16 eyes (3.31%); postoperative steroid use induced in 11 eyes (9.07%), due to angle closure by air bubble in anterior chamber in 4 eyes (0.82%), and due to angle closure by big bubble in anterior chamber in 1 eye (0.21%). Cataract was also observed as a postoperative complication in 7 eyes (1.45%). Stromal graft rejection was observed in 3 eyes (0.61%). Suture-related infiltrates were seen in 2 eyes (0.41%), and dense infiltrate in the interface was seen in 1 eye (0.21%). There were uncommon complications such as graft dehiscence due to trauma in 2 eyes (0.41%), filamentary keratitis in 2 eyes (0.41%), abscess related to sutures were observed in 1 eye (0.21%), vascularization of sutures was observed in 2 eyes (0.42%) with vernal keratoconjunctivitis, recurrence of corneal dystrophy was observed in the donor tissues in 2 eyes (6.8%) out of 27 eyes of macular corneal dystrophy and with 2 eyes (7.4%) out of 29 eyes with granular corneal dystrophy [Figure 2]. [Table 3] shows the list of all the complications with their respective percentage. | Figure 1: Intraoperative complications (a) Outcome after macroperforation of Descemet's membrane (b) Outcome after microperforation of Descemet's membrane (c) Preoperative anterior segment optical coherence tomography picture of healed acute hydrops (d) Postoperative picture of the same patient showing healed Descemet's perforation
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 | Figure 2: Slit-lamp photograph of postoperative complications showing (a) Double anterior chamber (b) postoperative picture of the same patient after management (c) raised intraocular pressure with graft edema (d) Therapeutic DALK performed in descemetocele with minimal central scarring (e) Interface infectious keratitis (f) recurrence of granular corneal dystrophy (g) Descemet's membrane detachment after suture removal (h) same patient after corrective suturing of detached Descemet's membrane (i) stromal graft rejection
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The best corrected visual acuity postoperatively was in the range of 6/6-6/12 in 438 eyes (90.6%), 6/18-6/36 in 41 eyes (8.5%) which included 12 eyes treated for macular corneal dystrophy, 8 eyes for granular corneal dystrophy, 6 eyes for descemetocele, 6 eyes had amblyopia, 4 eyes had high astigmatism and 2 eyes had macular scar. <6/36 was observed in 4 eyes among which 1 eye had traumatic aphakia, 1 eye had retinal detachment, 1 eye had neurotrophic keratitis, and 1 eye had abscess at suture tract.
| Discussion | | |
DALK has been performed for anterior corneal diseases by experienced surgeons as it demands special skills with a longer learning curve. Over the period of time DALK procedure has been evolved for the benefit of surgeons and also to reduce the intraoperative complications associated with the conventional penetrating keratoplasty. However, multiple complications are reported intraoperatively and postoperatively in DALK and various measures are adopted to overcome these complications. Here in this article, we analyzed various complications which occur during various stages of surgery and after the surgery. [Table 4] shows the comparison of incidence of complications of other studies with our study. | Table 4: Comparison of deep anterior lamellar keratoplasty complications of other studies with our study
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Descemet's membrane perforation
Descemet's membrane perforation has been reported as one of the intraoperative complications in various studies. This complication can happen during trephination, during stromal air injection, during manual layer-by-layer dissection, or during suturing. In our study, perforation occurred in 32 cases (6.51%) which was observed during layer-by-layer dissection in 18 eyes (58.06%) of patients treated for healed hydrops, 2 eyes (6.45%) during air bubble injection, 10 eyes (32.2%) during Type 2 big-bubble formation, and 1 eye (3.22%) during suturing. Olivia S Huang et al. conducted a study showing perforation in 101eyes (18.7%) which included 79 eyes (78.2%) with microperforations and 15 eyes (14.9%) with macroperforation. During deep lamellar dissection (32 cases; 31.7%), air injection (27 cases; 26.7%), and during suturing (21 cases; 20.8%).[4] Lecissotti A et al.[4] conducted a study on prognosis of patients with intraoperative Descemet's membrane perforation which occurred in 8 eyes (23%), in 5 eyes during manual deep dissection and in 1 eye each during trephination, suturing, and while collapsing Big Bubble.[3] A similar outcome was noted with other studies.[5],[9],[10] Its management depends on the size and location of perforation and stage at which the perforation happened, if it happened during initial stage of trephination then depending upon the size of perforation, micro perforations toward the end of dissection were continued as DALK and macroperforations in the initial stage of dissection, especially if central were converted to penetrating keratoplasty. When the perforation happened during layer-by-layer stromal dissection then the dissection was performed away from the perforation site, all around the perforation first leaving a small bit of posterior stroma above the perforation and eventually sealing it with air bubble in the anterior chamber. Perforation which happened during suturing technique was also managed with air bubble in anterior chamber.
Graft rejection
Graft rejection is comparatively uncommon in DALK as it overcomes endothelial rejection,[11] however, epithelial and stromal graft rejections are still bound to happen. Antigen-presenting cells should be able to reach the donor stroma through 2 pathways: (1) via intrastromal recognition, that is, antigen-presenting cells could migrate into the stromal tissue via stromal fibers, or (2) via infiltrating vessels in the high-risk model.[12] In our study, stromal graft rejection occurred in 3 eyes (0.61%), all 3 eyes had vernal keratoconjunctivitis with active inflammation, which were successfully managed with topical steroids. Stromal graft rejections can be well managed with aggressive topical steroids (prednisolone 1% hourly) as observed in many studies,[6],[13],[14] also prompt treatment avoids its long-term complications such as graft vascularization and poor visual outcomes. Its incidence can range from 1 to 29%.[14]
Rise in intraocular pressure
Rise in Intraocular pressure is a rare occurence but needs attention and prompt treatment. Its incidence is observed from zero to 9%.[15] Overall this rise in IOP was observed in 16 eyes (3.31%) due to long-term steroid use in 11 eyes (68.75%) which was treated by regulating its dose, due to air bubble injection in anterior chamber was seen in 4 eyes (25%) leading to pupillary block and subsequent secondary angle closure.[16] In 1 eye (6.25%), it was due to reverse pupillary block due to big bubble. Muse et al. conducted a study to report the incidence of raised IOP post DALK, which happened in 12 eyes (17%) out of 69 cases and all were related to temporary rise due to prolonged topical steroid use in the postoperative period.[8] Multiple other studies have been documented showing raised IOP post DALK.[17],[18]
Double anterior chamber
This complication occurs commonly in patients with breaks in Descemet's membrane and air bubble in anterior chamber.[19] In our study 3 eyes (0.61%) had double anterior chamber and were managed conservatively in 2 cases The incidence of double anterior chamber has been quite common post DALK and is reported in multiple studies.[20],[21]
Suture-related complications
As an observation suture-related complications like suture loosening, vascularization, and sterile reactions and infiltrates are observed more commonly in DALK.[19] In our study suture infiltrates were seen in 2 eyes (0.41%), suture-related vascularization observed in patients with vernal keratoconjunctivitis was seen in 2 eyes (0.41%) and one of the dreadful complications as suture-related abscess was observed in 1 eye (0.21%). El Sayed et al. study encountered loosening of the sutures in 11 cases (23.4%) and vascularization of the sutures in 3 cases (6.4%).[2]
Interface-related complication
As interface is a potential space for growth of micro-organisms, interface keratitis has been one of the intractable complications because of its location as the sample collection and drug penetration is remotely accessible. Thankfully its incidence is very low and most commonly occurs after contamination of donor graft and mostly with Candida species.[22] In our study, it occurred only in 1 eye (0.21%) and was successfully managed by modified debulking. Kodavoor et al. also reported a case of interface fungal keratitis which was successfully managed aggressively with topical antifungal medication.[23] The rate of interface keratitis caused by fungal agent post DALK is reported as 0.052%.[24] Multiple case reports are documented and were treated successfully.[22],[25]
Recurrence of hereditary stromal dystrophies
Until now 18 cases of recurrence in Granular corneal dystrophy have been recorded from 6 months to 8.5 months with varying patterns.[26] In our study, 2 eyes (0.41%) showed its recurrence hence, it becomes source of its incidence. A study conducted by Sogutlu Sari et al. on recurrence of macular corneal dystrophy reported it as 5.7%,[27] however it was observed only in 2 eyes (0.41%) in our study. A comparative study was conducted by Kodavoor et al. between the outcome of macular and granular corneal dystrophy which concluded comparable results.[28]
Miscellaneous complications
Some uncommon complications were observed in our study which are necessary to be reported such as filamentary keratitis was observed in 2 eyes (0.41%) and was well managed with lubricating drops also traumatic dehiscence of the graft was observed in 2 eyes (0.41%). Traumatic dislocation was reported in one case (0.21%) which required penetrating keratoplasty on an emergency basis. Also, traumatic aphakia, neurotrophic keratitis, and retinal detachment were observed as a solitary postoperative complication. Descemet's membrane separation after suture removal was observed in 1 eye, and the patient was successfully managed with corrective resuturing at the site of detachment.
Cataract
Cataract was observed in 7 eyes (1.45%) post DALK, mostly steroid induced causing posterior subcapsular cataract among which 3 cases needed cataract surgery with IOL implantation. A number of studies have already confirmed lesser incidence of cataract post DALK as compared to penetrating keratoplasty.[29],[30]
In our study, therapeutic DALK was performed in 6 eyes with descemetocele and all had successful outcomes, a study was conducted by Nguyen et al. in which Therapeutic DALK was performed successfully in all 24 cases.[31]
| Conclusion | | |
DALK as an alternative to penetrating keratoplasty for anterior corneal stromal diseases has proven to be better time and again. It has become an automatic choice for diseases of anterior cornea requiring keratoplasty, but it is not without complications. Complications occurring at any stage of surgery can be identified and managed effectively resulting in optimal outcome. This article compiles complications post DALK.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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| 31. | Nguyen HT, Pham ND, Mai TQ, Do HT, Nguyen DT, McCluskey P, et al. Tectonic deep anterior lamellar keratoplasty to treat corneal perforation and descemetocele from microbial keratitis. Clin Ophthalmol 2021;15:3549-55. |
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]
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