Surgical approach for scleral ischemia and melt

Management of scleral melt

Scleral melting, while rare, can lead to significant ocular morbidity. Several possible risk factors for scleral melt have been identified, such as infection, autoimmune disease, trauma, and post-surgical state, and these may act in combination with each other. Treatment should be tailored according to the etiology and severity of the scleral melt. Medical management may be indicated, especially in cases of autoimmune-related melt; however, surgical procedures are often necessary due to compromised ocular integrity and limited penetration of medications into the avascular sclera. An understanding of the surgical options available and their operative outcomes is particularly important when choosing the appropriate treatment protocol for each patient.

The role of Tenonplasty in the management of limbal and scleral ischemia due to acute ocular chemical burns

Of the various manifestations of ocular chemical burns (OCBs), ischemia of the limbus and the peri-limbal sclera indicates poor prognosis and in severe cases threaten the integrity of the globe. Tenonplasty is a surgical procedure which involves advancing the Tenon’s capsule over the ischemic areas to provide a vascular supply and to enable migration of the conjunctival epithelium. This review aims to provide an overview of the diagnosis of limbal ischemia and its management with Tenonplasty. A literature review was conducted using the keywords “Tenonplasty,” “Tenon’s capsule,” “ocular chemical injury,” “ocular thermal injury,” “Tenon advancement,” “scleral ischemia,” and “limbal ischemia,” and outcomes were studied from seven selected articles. In addition to clinical evaluation, in vivo imaging techniques such as anterior segment optical coherence tomography angiography can provide an objective method of measuring and monitoring the ischemia and re-perfusion of the peri-limbal vasculature. Tenonplasty can be performed in eyes with acute OCBs with scleral or limbal ischemia by dissecting the Tenon’s layer from the orbit and securing it to the limbus. The indications, mechanism of action, peri-operative considerations, surgical technique, and post-operative care of Tenonplasty are discussed in detail. The average time for post-operative re-epithelization ranges from 1 to 6 months with the formation of a symblepharon being the most common complication. In conclusion, Tenonplasty is a globe-salvaging procedure in cases with severe limbal and scleral ischemia because of OCBs and has good anatomical outcomes priming the globe for subsequent re-constructive and vision-restoring surgeries.

The clinical and pathogenic spectrum of surgically-induced scleral necrosis: A review

The onset of scleral necrosis after ocular surgery may have catastrophic ocular and systemic consequences. The two most frequent surgeries causing surgically-induced scleral necrosis (SISN) are pterygium excision and cataract extraction. Several pathogenic mechanisms are involved in surgically induced scleral necrosis. All of them are poorly understood. Ocular trauma increasing lytic action of collagenases with subsequent collagen degradation, vascular disruption leading to local ischemia, and immune complex deposition activating the complement system represents some of the events that lead to scleral necrosis. The complex cascade of events involving different pathogenic mechanisms and the patient's abnormal immune response frequently leads to delayed wound healing that predisposes the development of scleral necrosis. The management of SISN ranges from short-term systemic anti-inflammatory drugs to aggressive immunosuppressive therapy and surgical repair. Therefore, before performing any ocular surgery involving the sclera, a thorough ophthalmic and systemic evaluation must be done to identify high-risk patients that may develop SISN.

Management Strategies of Ocular Chemical Burns: Current Perspectives

Ocular chemical burns are absolute ophthalmic emergencies and require immediate management to minimize devastating sequelae. Management of alkali and acid burns is started at the scene of the accident by copious irrigation. Treatment is directed at improving epithelial integrity and stromal stability, reduction of undue inflammation, and prevention or timely management of complications. To ascertain the best possible outcome, numerous biological medications and surgical interventions have been merged into conventional therapeutic regimens. These include autologous and umbilical cord serum preparations, platelet-rich plasma, amniotic membrane transplantation, limbal stem-cell transplantation, and anti-angiogenic agents.

Preserved Corneal Lamellar Grafting Reduces Inflammation and Promotes Wound Healing in a Scleral Defect Rabbit Model

Purpose

To investigate the effect of preserved corneal lamellar grafting on inflammation and wound healing and to compare its effect with that of preserved scleral grafting in a scleral defect rabbit model.

Methods

New Zealand White rabbits were assigned to a corneal lamellar grafting group (n = 5) or a scleral grafting group (n = 5). After lamellar dissection of superotemporal sclera using 6.0-mm trephine, the same sizes of preserved human corneal or scleral grafts were transplanted with 10-0 nylon interrupted sutures. The grafted areas were photodocumented at 3 to 21 days after surgery to evaluate epithelial wound healing index (%), neovascularization and presence of filaments. The existence of CD3⁺ T cells and CD34⁺ cells at the grafted areas was analyzed at 21 days.

Results

Epithelial wound healing index was significantly higher in the corneal grafting group at 9 days (P < 0.05). Scleral grafts showed copious formation of filaments adherent to the engrafted area from 9 to 14 days, whereas the corneal grafts were free of filaments. The numbers of inflammatory cells were significantly higher in the scleral grafts (P < 0.05), and CD3⁺ T cells and CD34⁺ cells were populated within inflammatory cells at graft-recipient junctions in both groups. The mean areas of the estimated perigraft and intragraft neovascularization tended to be higher in scleral grafts.

Conclusions

Preserved corneal lamellar grafting enhances epithelial wound healing and alleviates inflammation in a scleral defect rabbit model.

Translational Relevance

This work suggests that the preserved corneal graft may be considered as a favorable alternative option for repairing scleral defects.

Transplantation of autologous perichondrium with amniotic membrane for progressive scleral necrosis

PURPOSE

Scleral necrosis with severe ischemia is refractory to conventional treatment because of avascular progressive necrosis. We assessed the therapeutic efficacy and safety of autologous perichondrium transplantation in patients with progressive scleral necrosis (PSN) and analyzed the clinical effects.

METHODS

This study was a prospective, interventional, and noncomparative case series. Reconstructive surgery using autologous perichondrium and amniotic membrane (AM) was performed in patients with PSN who showed progressive ischemic scleral melting with impending perforation state and/or broad avascular area larger than 10 mm in diameter. The primary outcome was restoration of scleral integrity with healthy vascularized epithelium over the graft at six months after surgery. The secondary outcome was complication rate associated with autologous perichondrium graft use.

RESULTS

Eighteen eyes of 14 patients underwent reconstructive surgery using autologous perichondrium patch and AM grafts. Observations indicated the graft provided the eyeball with successful structural integrity in 17 out of the 18 cases (94.4%) at six months after surgery. One eye showed a small scleral defect due to wound dehiscence at four month after the surgery. Additional surgery using perichondrium and AM stabilized the eye. The scleral necrosis healed completely after perichondrium and AM transplantation, even in cases with full-thickness scleral defect. The scleral integrity was maintained until the last follow-up session. There were no serious complications of endophthalmitis or graft infection.

CONCLUSIONS

Reconstructive surgery using autologous perichondrium and AM is an effective method for restoration of scleral integrity and vascularization of the episclera and conjunctiva in eyes with PSN. Therefore, autologous perichondrium can be considered as an appropriate new biologic tissue for PSN.

Isolation of acid from eye drop bottles being used by patients presenting with presumed scleritis

Purpose:

The aim of the study was to report the occurrence of contamination/replacement of ophthalmic eye drops with liquids of acidic nature in patients treated for nonresponding scleritis.

Methods:

This was a retrospective interventional case series study.

Results:

Of the three patients (4 eyes) referred as necrotizing scleritis, two were found to have acid as the content in the bottle/s being used as eye drops, confirmed using biochemical tests. All four eyes had tarsal ischemia and tarsal conjunctival defect in addition to severe scleral ischemia involving the inferior bulbar area. All four eyes required tenonplasty with amniotic membrane transplant more than once for the ocular surface to heal. Two of the three patients were on systemic immunosuppressives including pulse cyclophosphamide for refractory necrotizing scleritis. Sulfuric and hydrochloric acid was isolated from the bottles of 2^nd and 3^rd patient using confirmatory biochemical tests.

Conclusion:

It is important to be aware of the possibility of contaminating or replacing contents of eye drops with harmful agents of acidic nature and should be considered in situations that resemble the clinical picture described herein.

Combined Tenonplasty and Scleral Graft for Refractory Pseudomonas Scleritis Following Pterygium Removal with Mitomycin C Application

Purpose

To report a surgical approach combining scleral patch graft and tenonplasty for successful management of refractory Pseudomonas scleritis following pterygium removal with mitomycin C application.

Case Report

A 75-year-old diabetic woman with a history of prior pterygium excision and mitomycin C application developed infectious necrotizing scleritis caused by Pseudomonas aeruginosa. Owing to progression of scleritis despite medical management, the patient underwent surgery. Intraoperatively, extensive scleral ischemia was noted. Therefore, debridement of the necrotic tissue, scleral graft, tenonplasty to bring blood vessels to the ischemic sclera, and amniotic membrane transplantation were performed. Postoperatively, no signs of ischemia or recurrence of infection were observed. During 6 months of follow-up, the patient achieved complete restoration of the globe integrity with a non-inflamed ocular surface.

Conclusion

Through restoration of blood supply to the ischemic sclera, tenonplasty is an effective adjunctive procedure in addition to conventional scleral patch graft for the treatment of refractory Pseudomonas scleritis associated with ischemia.

Current and Upcoming Therapies for Ocular Surface Chemical Injuries

Chemical injuries frequently result in vision loss, disfigurement, and challenging ocular surface complications. Acute interventions are directed at decreasing the extent of the injury, suppressing inflammation, and promoting ocular surface re-epithelialization. Chronically, management involves controlling inflammation along with rehabilitation and reconstruction of the ocular surface. Future therapies aimed at inhibiting neovascularization and promoting ocular surface regeneration should provide more effective treatment options for the management of ocular chemical injuries.

Update on amniotic membrane transplantation

Cryopreserved amniotic membrane modulates adult wound healing by promoting epithelialization while suppressing stromal inflammation, angiogenesis and scarring. Such clinical efficacies of amniotic membrane transplantation have been reported in several hundred publications for a wide spectrum of ophthalmic indications. The success of the aforementioned therapeutic actions prompts investigators to use amniotic membrane as a surrogate niche to achieve ex vivo expansion of ocular surface epithelial progenitor cells. Further investigation into the molecular mechanism whereby amniotic membrane exerts its actions will undoubtedly reveal additional applications in the burgeoning field of regenerative medicine. This article will focus on recent advances in amniotic membrane transplantation and expand to cover its clinical uses beyond the ocular surface.

Surgical treatment of necrotic scleral calcification using combined conjunctival autografting and an amniotic membrane inlay filling technique

PURPOSE

To introduce a novel technique to treat necrotic scleral calcification caused by previous regional conjunctivectomy using conjunctival autografting and amniotic membrane inlay filling, and to evaluate the clinical outcome.

METHODS

Ten patients (11 eyes, 12 regions) who had undergone regional conjunctivectomy with postoperative mitomycin C (MMC) for pterygia or pingueculae were included. Scleral calcification was removed using a bevel-down crescent knife. After the conjunctival donor tissue was harvested from the upper bulbar conjunctiva, the tissue was grafted to the scleral defect and secured with sutures. Amniotic membrane was inserted randomly into spaces between the conjunctival graft and the scleral bed. Protective amniotic membrane was transplanted over the graft, with stromal side up.

RESULTS

Scleral calcification developed in ischaemic areas in 11 of the 12 regions; 50% of cases had a surface defect seen with a fluorescent dye. The grafted conjunctiva epithelialized successfully in all cases. In 10 regions, the epithelialization occurred in 1 or 2 weeks. In the remaining two regions, one region required another surgery because of graft failure, and epithelialization occurred in the last region in 9 weeks. Vascular growth into the graft from the surrounding tissue occurred in all cases in 1 to 10 weeks. The surgical wound stabilized 3 weeks postoperatively.

CONCLUSION

The combined technique had high success rates of graft survival and good revitalization of the necrotic area of scleral calcification, eliminated the need for invasive and time-consuming scleral autografting or allografting, and provided good cosmesis. Scleral ischaemia, which was caused by MMC, may induce scleral calcification.

Late-onset intrascleral dissemination of Stenotrophomonas maltophilia scleritis after pterygium excision

PURPOSE

To report a case of pterygium excision-related infectious scleritis with late-onset intrascleral dissemination.

METHODS

Case report.

RESULTS

A 72-year-old female patient was referred for Stenotrophomonas maltophilia scleritis after undergoing pterygium excision 18 years earlier. Surgical debridement and a tectonic corneal patch graft, along with conjunctival flap, were performed to repair the scleral defect after treatment with fortified topical and systemic antibiotics. However, intrascleral dissemination of scleritis occurred 5 months after the initial episode.

CONCLUSIONS

Intrascleral dissemination of S. maltophilia scleritis after pterygium excision might be delayed because of limited invasiveness and inherent resistance to several antibiotics. Long-term follow-up may be needed to protect against the possibility of late-onset intrascleral dissemination.

Temporary sutureless amniotic membrane patch for acute alkaline burns

OBJECTIVE

To evaluate the clinical outcome of a new sutureless approach for a temporary amniotic membrane patch (ProKera; Bio-Tissue, Inc, Miami, Florida) in eyes with acute burns.

METHODS

Retrospective review of 5 eyes of 5 patients with grades I to III acute alkaline burns, receiving ProKera insertion within 8 days of injury.

RESULTS

These eyes had either total (2 cases) or extensive (60%-75%, 3 cases) corneal epithelial defects with limbal (120 degrees -360 degrees ) and conjunctival (30%-60%) epithelial defects. ProKera was inserted within a mean (SD) of 3.7 (3.1) days after burn and repeated 1 to 3 times for 3 cases. Conjunctival defects reepithelialized in 8.2 (5) days (range, 5-17 days), while limbal and corneal defects healed in 13.6 (8.3) days (range, 5-25 days). The latter was completed with circumferential closure of limbal defects followed by centripetal healing of corneal defects. In 3 eyes, early peripheral corneal neovascularization was followed by marked regression on completion of healing. During 16.8 (10.8) months of follow-up, all eyes retained a stable surface with improved corneal clarity, and without limbal deficiency or symblepharon.

CONCLUSION

This sutureless application of an amniotic membrane patch allows for early delivery of its biologic actions, which may help preserve remaining limbal stem cells for rapid expansion and prevent late cicatricial complications in eyes with mild and moderate acute alkaline burns.

Sutureless amniotic membrane transplantation for partial limbal stem cell deficiency

PURPOSE

To evaluate the results of sutureless amniotic membrane (AM) transplantation using fibrin glue for reconstructing corneal surfaces with partial limbal stem cell deficiency (LSCD).

DESIGN

Retrospective noncomparative interventional case series.

METHODS

Eleven eyes of nine patients that had LSCD with 120 degrees to almost 360 degrees of limbal involvement underwent superficial keratectomy to remove the conjunctivalized pannus followed by AM transplantation using fibrin glue. Additional sutureless AM patch (ProKera; Bio-Tissue, Inc, Miami, Florida, USA) was used in seven patients, and mitomycin C was applied on the cornea in four eyes and during fornix reconstruction in seven eyes. The surgery was repeated in three eyes for residual pannus.

RESULTS

During a mean follow-up of 14.2 +/- 7.7 months (range, six to 26 months), all eyes maintained a smooth and stable corneal epithelial surface without recurrent erosion or persistent epithelial defect, and showed less stromal cloudiness and vascularization. Best-corrected visual acuity improved in nine eyes (81.8%). Corneal epithelialization proceeded by epithelial growth over AM (n = 4), accompanied by dissolution of AM (n = 4) or a combination of both (n = 3). No complication was noted regarding initial or repeated uses of fibrin glue.

CONCLUSION

AM transplantation using fibrin glue appears to be a safe and effective method of restoring a stable corneal epithelium for cases with partial LSCD. This approach avoids the need of transplanting limbal epithelial stem cells.