Oral Buccal Mucous Membrane Allograft With a Corneal Lamellar Graft for the Repair of Boston Type 1 Keratoprosthesis Stromal Melts

Successful use of conjunctival flaps to prolong survival of type I keratoprosthesis in severe bilateral chemical burns: two case reports

INTRODUCTION

This report describes the use of conjunctival flaps to enable the survival of type I keratoprosthesis (KPro) in two cases of bilateral severe total limbal stem cell deficiency (LSCD) following chemical burns.

PRESENTATION OF CASE

Two patients had a history of bilateral chemical injury with lime. On examination, the presenting vision was light perception to hand motions and both cases had conjunctivalized ocular surfaces with symblepharon. A modified technique of type I keratoprosthesis was used, where the conjunctivalized corneal pannus was dissected and lifted off as an inferior fornix-based conjunctival flap. This was followed by a standard surgical technique of type I KPro. The flap was then secured over the device and optical opening was made two weeks later. Both the patients had stable ocular surfaces with visual acuity of 20/20 at 2-7 years of follow-up.

DISCUSSION

In patients with total LSCD with adnexal involvement, type I KPro has unsatisfactory long-term survival because of the risk of repeated epithelial breakdowns and stromal ulceration. With the innovative approach described in this report, type I KPro can be successfully used for sustainable visual improvement in the presence of severe ocular surface disease and symblepharon.

CONCLUSION

Conjunctival flaps can be used along with type I KPros to improve long-term survival and give sustainable visual outcomes in cases of bilateral corneal blindness due to advanced ocular surface damage.

Surgical Management of the Ocular Surface in Neurotrophic Keratopathy: Amniotic Membrane, Conjunctival Grafts, Lid Surgery, and Neurotization

PURPOSE

To review the surgical modalities available to treat Mackie stage 2 and stage 3 neurotrophic keratopathy.

METHODS

Literature review and technique descriptions.

RESULTS

The following procedures are described in detail with accompanying videos: temporary, permanent, and botox-assisted tarsorrhaphy; amniotic membrane transplant; keratoplasty with amniotic membrane and tarsorrhaphy augmentation; Gunderson and conjunctival pedicle flaps; buccal graft transplantation; and neurotization.

CONCLUSION

A variety of surgical options exist to manage neurotrophic keratopathy when medical treatments alone fail to resolve epitheliopathy. Ongoing protection and optimization of the ocular surface health remains crucial to prevent recurrent epithelial breakdown.

Transmucosal Boston Keratoprosthesis Type I in a Patient With Advanced Ocular Cicatricial Pemphigoid

PURPOSE

To describe a novel surgical technique using the Boston Keratoprosthesis (KPro) type I in a patient with advanced ocular cicatricial pemphigoid (OCP) using oral mucosa for covering the prosthesis.

METHODS

We present the case of an 85-year-old man previously diagnosed with type 2 diabetes and advanced OCP nonresponsive to immunosuppressive treatment, whose best-corrected visual acuity was light perception and projection in both eyes. After examination, Boston KPro type I in the right eye was contemplated because osteo-odonto KPro and Tibial bone KPro were not feasible because of the patient's osteoporosis and edentulism. Reconstruction of the ocular surface was first performed using oral mucosa to release the symblepharon and try to deep the fornices. Three months later, the oral mucosa was lifted, and the Boston KPro type I was implanted using the patient's own cornea. Then, a modification of the standard surgical technique was carried out, replacing the use of contact lens for covering the prosthesis with an oral mucosa graft with a central trephination as an alternative option in fornix foreshortening cases.

RESULTS

After 11 months, visual acuity was stable to 0.2 decimal. No postoperative complications have been encountered, and prosthesis was in place.

CONCLUSIONS

The surgical technique of transmucosal Boston KPro type I may be considered a surgical alternative in patients with advanced OCP who present with severe fornix foreshortening, where osteo-odonto KPro or Tibial bone KPro cannot be performed due to osteoporosis or edentulism or when the Boston KPro type II is not readily available.

Corneal transplantation outcomes after the extrusion of an intrastromal keratoprosthesis: a pilot study

This short report includes 5 eyes of 5 patients (mean age 63.2 ± 12 years) who underwent a tectonic keratoplasty [deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK)] in order to rehabilitate the eye after the extrusion of the non-perforating keratoprosthesis (Kpro) KeraKlear (KeraMed, USA). The non-perforating Kpro was extruded after a mean period of 21.4 ± 21.8 months due to melting. In two cases, the keratoplasty was performed the same day of the non-perforating Kpro removal due to a severe melting, while in the other three cases it was performed one to 3 months later. Two eyes received a DALK, but in 3 eyes a macroscopic Descemet membrane perforation forced the conversion into a PK. The mean follow-up period after the keratoplasty was 16.8 ± 6.6 months. No cases of rejection were recorded. All the 5 eyes achieved “anatomical success” (transparent graft, with no signs of infection or inflammation). Two eyes showed limited “functional success” because the achievement of the best visual potential was prevented by the development of glaucomatous optic atrophy during the follow-up period. In conclusion, this short report presents an unexpected success of a keratoplasty performed with a tectonic purpose after the extrusion of the non-perforating Kpro because the corneal graft remained transparent, without neovascularization or scarring during the follow-up period. This initial evidence shows some encouraging results regarding graft survival rate and the achievement of a useful visual rehabilitation with keratoplasty after a non-perforating Kpro failure instead of repeating the Kpro implantation.

Boston Type 1 Keratoprosthesis: Updated Perspectives

The use of Boston type 1 keratoprosthesis (BKPro) has significantly increased worldwide. It is no longer considered a procedure of last resort but a reasonable option for patients with otherwise poor prognosis for a traditional penetrating keratoplasty. BKPro was approved by the Food and Drug Administration in 1992 for bilateral severe corneal blindness due to multiple corneal transplant failure. Over the years, indications have extended beyond recurrent immunologic rejection to include other conditions such as chemical injury and other causes of bilateral limbal stem cell deficiency, extensive corneal neovascularization, neurotrophic corneas and hypotony, among others. Numerous advances in the design of the BKPro, improvement of preoperative, intraoperative and postoperative management have resulted in favorable outcomes and a reduction in postoperative complications. Accordingly, many studies have shown that implantation of this device is highly effective in restoring vision with very good short-term outcomes. However, due to the lifetime risk of sight-threatening complications after BKPro implantation, a longer follow-up period should provide outcomes that are more realistic. In this review, the authors examined only the results of publications with an average of at least 2 years of follow-up. The overall intermediate to long-term visual outcomes and retention rate in BKPro seem to be favorable. However, autoimmune diseases and cicatrizing conditions continue to show a higher incidence of postoperative complications that require further management.

Assessing full thickness oral mucosal grafting: complications and postoperative outcomes in a broad collective of patients

Background

Conjunctival defects can be repaired with several mucosal tissues. The simplicity of harvesting oral mucosa and its wide availability makes it the preferred graft tissue for all indications requiring mucosal grafting. Through analysing the postsurgical outcomes and rate of revisions, this study explores the suitability of oral mucosa grafts, depending on the initial diagnosis.

Methods

We reviewed all the files of patients with a history of oral mucosal graft surgery, performed at our clinic between 2012 and 2018, focusing on complications and revision rates.

Results

In total, we analysed 173 oral mucosa grafts in 131 patients. The most common initial diagnosis was tumour resection, followed by surgical complications, postenucleation socket syndrome, trauma and ocular surface disorders. Complication and revision rates depended highly on the initial diagnosis. Revision rates were highest if the initial diagnosis included ocular surface disorders or chemical trauma.

Conclusions

Oral mucosa grafting (OMG) is the most effective treatment for a wide range of ocular conditions involving conjunctival defects. Conjunctival defects that result from trauma or cicatricial surface diseases seem less suitable for OMG and may benefit from alternative graft tissue or treatment options.

Multidisciplinary Treatment to Restore Vision in Ocular Burns

Periorbital burns generate contraction and distortion of periorbital soft tissue, causing eyelid malfunction, further contributing to loss of vision from corneal scarring or perforation. We present our multidisciplinary algorithm to restore vision in patients with burn-related bilateral corneal blindness with light perception. Chart review was performed for four consecutive burn patients requiring periocular reconstruction and keratoprosthesis. Initial treatment included globe coverage with eyelid releases and grafts. Strategy of corneal replacement was determined by eyelid position and function and sufficiency of tear production. All patients were corneal blind with light perception only and cicatricial ectropion. The eye with better visual prognosis was reconstructed. Eyelid reconstruction procedures consisted of lid releases with full-thickness skin graft (FTSG) or split-thickness skin graft (STSG). Two patients regained adequate lid function and underwent standard keratoprosthesis placement. Two underwent mucous membrane grafts followed by keratoprosthesis. All patients experienced improved postoperative vision in their reconstructed eye. Corneal injury due to periocular burns can lead to blindness. Early involvement of ophthalmology, protective measures, and early ectropion release are critical. For severe burns, a multidisciplinary approach, where adequate globe protection is followed by keratoprosthesis placement, can effectively restore vision in patients with burn-related corneal blindness.

Oral mucosa grafting in periorbital reconstruction

To provide an extensive literature review on the clinical indications of oral mucosa grafts (OMG) and minor salivary gland grafts (MSGG) in periorbital reconstruction together with safe practice graft harvesting techniques to minimize donor-site morbidity. A literature review was performed by searching the databases of PUBMED, EMBASE, and COCHRANE library using the keywords: minor salivary glands; oral mucosal graft; orbit; and eye. The bibliographies of the pertinent articles were examined for additional papers. Indications for OMG include treatment of recurrent pterygia; socket contracture in anophthalmic patients; repair of eyelid deformities; ocular surface and fornix reconstruction following tumour resection, cicatricial ocular surface disorders, or chemical burns. More novel uses include repair of glaucoma aqueous drainage device erosions or leaking trabeculectomy blebs; scleral buckle exposure; and keratoprosthesis-related corneal melts as well as lining the dacryocystorhinostomy tract to prevent closure. Simultaneous MSGG transplantation may be used in the treatment of severe dry eyes or dry anophthalmic cavities. Harvesting from the inner cheek is preferred to lower lip as it causes less post-operative discomfort and neurosensory deficits. Suturing is recommended for smaller ovoid grafts as it allows less painful closure without tension, while larger rectangular defects are best left to heal by secondary intention. OMG and MSGG transplantation is a viable alternative to replace conjunctiva and restore the ocular surface. The donor site is readily accessible and widely available in most patients, grafting is fast and cheap, and the same site may undergo repeated harvesting with few donor site complications.

Extraoral Uses of Autologous Oral Soft Tissue Grafts: A Different Bridge Between Mouth and Body Health

Focused Clinical Question: Are there any extraoral uses for intraoral soft tissue grafts? Summary: Despite extensive literature on the intraoral uses of soft tissue autografts harvested from oral sites, the periodontal literature is lacking information on the extraoral uses of such grafts. The purpose of this article is to review the autologous use of certain oral soft tissue grafts for extraoral indications. A literature search revealed that several medical specialties, including otolaryngology, ophthalmology, dermatology, plastic surgery, and urology, have a track record of positive outcomes with the use of free gingival, buccal fat pad, and buccal mucosa grafts for a wide variety of reconstructive procedures at diverse body sites. Conclusions: The numerous successful extraoral uses of oral soft tissue autografts underscore the versatility of these tissues in reconstructive surgery and suggest there is potential for collaboration between periodontal and medical specialists for the benefit of patients in need of such reconstructions. Broader awareness of these applications of oral soft tissue grafts could help expand their current uses and would allow practitioners to better answer possible patient inquiries.

Incidence, Risk Factors, and Surgical Management of Boston Type 1 Keratoprothesis Corneal Melts, Leaks, and Extrusions

PURPOSE

To determine the rate of Boston type 1 keratoprosthesis (Kpro)-related corneal melts, leaks, and extrusions requiring surgical repair and to analyze possible risk factors and visual outcomes.

METHODS

Retrospective chart review of 110 patients (128 eyes) who received a Kpro between November 2004 and December 2010 (average follow-up of 29 mo). The rate of corneal complications, risk factors for melts, and postmelt repair visual outcomes were evaluated.

RESULTS

Twenty eyes from 18 patients developed Kpro-related melts requiring surgical repair. The incidence of melt-related complications was 16%. In total, there were 33 episodes of melt-related complications. Surgical repair included lamellar patch grafts (15), Kpro removal with penetrating keratoplasty (7), reassembly of Kpro onto a new cornea (4), replacement of Kpro (3), suturing of a leak (3), and enucleation (1). The majority of eyes (18/20) did not regain their best post-Kpro vision at final follow-up (average 10 mo and range, 1-36 mo after melt repair). Significant risk factors for melt included previous infectious keratitis [P < 0.0001, odds ratio (OR) = 12.50, 95% confidence interval (CI), 4.02-38.9] and conjunctival deficiency (ie, a diagnosis of Stevens-Johnson syndrome, mucous membrane pemphigoid, or chemical injury, P = 0.043, OR = 2.66, CI, 1.01-7.02).

CONCLUSIONS

Patients who undergo Kpro with severe ocular surface disease are at greater risk for corneal melts, leaks, and extrusions. Patients with infectious keratitis and conjunctival deficiency are at an increased risk of developing corneal melts. Visual outcomes are poor after surgical repair of these complications.

Type 1 Boston keratoprosthesis: outcomes at two Canadian centres

OBJECTIVES

To report the outcomes of patients who underwent Boston type 1 keratoprosthesis (Kpro) surgery at the University Health Network (Toronto, Ont.) and the University of Ottawa Eye Institute (Ottawa, Ont.) between June 2008 and July 2013.

DESIGN

Retrospective case series.

PARTICIPANTS

Forty-four eyes of 43 patients who underwent Kpro surgery.

METHODS

A retrospective review was conducted of all Kpro procedures performed by 4 attending cornea surgeons. The preoperative characteristics and postoperative course of each patient were analyzed.

RESULTS

In 31 eyes (70%), the primary indication for a Kpro was failed corneal transplantation. The remaining 13 eyes (30%) had Kpro as a primary procedure. In all eyes, preoperative visual acuity (VA) was 20/150 or worse, with 39 eyes (89%) having a VA of counting fingers, hand movement, or light perception. Mean follow-up time was 21 ± 12 months (range 12-57 months). The retention rate at the last follow-up was 95%. Best-achieved median VA was 20/100 (range 20/20 to no light perception [NLP]), with 37% of patients achieving a VA of >20/40 at some point during their postoperative course. At the last follow-up, median VA was 20/400 (range 20/30 to NLP). The 2 most common complications included retroprosthetic membrane formation (23 eyes, 52%) and elevated intraocular pressure (10 eyes, 23%). There were 5 cases (11%) of stromal melt and 1 case (2%) of infective keratitis.

CONCLUSIONS

This study demonstrates that Kpro improves VA in a majority of cases, and is a viable option in situations in which there is a poor prognosis for traditional penetrating keratoplasty.

The Usage of a Conjunctival Flap to Improve Retention of Boston Type 1 Keratoprosthesis in Severe Ocular Surface Disease

PURPOSE

The Boston keratoprostheses type 1 devices (KPro) are utilized in cases unfavorable to penetrating keratoplasty. The prognosis remains guarded in cases of ocular surface disease due to risk of tissue necrosis. We describe a novel surgical approach using a conjunctival flap with a delayed opening to improve retention.

METHODS

In three patients with advanced cicatrizing conjunctivitis, a Type 1 keratoprosthesis was stabilized using a full tarsal conjunctival flap. Three months postoperatively, an opening was created in the flap overlying the optical portion of the device.

RESULTS

All patients had no device related complications over a mean follow-up period of 17.7 months (range 15-21 months) and vision remained excellent at better than 20/200 for all patients.

CONCLUSIONS

Utilization of a tarsal flap either primarily as part of a two stage modified technique or secondarily in cases of tissue necrosis and impending device extrusion might maximize retention of the type 1 KPro.

Long-term safety and efficacy of high-fluence collagen crosslinking of the vehicle cornea in Boston keratoprosthesis type 1

PURPOSE

The aim of this study was to evaluate the safety and efficacy of very high-fluence collagen crosslinking (CXL) as a means of achieving increased corneal rigidity and reduced enzymatic digestion in the vehicle cornea of Boston keratoprosthesis (KPro) type 1.

METHODS

Eleven consecutive patients fitted with a KPro (5 with a previous repeat cornea graft failure, 4 with ocular cicatricial pemphigoid, and 2 with chemical burn) underwent donor vehicle cornea pretreatment with very high-fluence prophylactic CXL in a 2-step procedure. First, the donor cornea was crosslinked with an intrastromal riboflavin instillation through a femtosecond laser-created pocket. This was followed up with a superficial CXL treatment. On the completion of the CXL pretreatment, the cornea center was trephined with the femtosecond laser, and the KPro was fitted onto the crosslinked donor cornea. Visual acuity, corneal surface, and donor vehicle cornea stability were evaluated. Follow-up evaluations were conducted over the next 9 years with a mean of 7.5 years.

RESULTS

Mean uncorrected visual acuity improved from light perception to 20/60. One patient required a follow-up surgery, because of significant melt in the host cornea. None of the eyes developed melts and/or infection, especially on the vehicle cornea on which the KPro was fitted.

CONCLUSIONS

Pretreatment with intrastromal and superficial very high-fluence CXL in conjunction with Boston type 1 KPro seems to be a safe and effective adjunctive treatment for achieving increased vehicle donor cornea rigidity. Additionally, there is an increased resistance to enzymatic degradation. This application may serve to enhance the biomechanical stability and external disease resistance of the donor vehicle cornea in patients with advanced external disease.

A year of cornea in review: 2013

PURPOSE

The goal of this study was to provide an update of significant corneal literature published in 2013.

DESIGN

This study is a systematic literature review.

METHODS

We conducted a systematic review of the English-language literature published from January 1, 2013, to December 31, 2013, using the following PubMed search and Medical Subject Headings terms: cornea transplantation, keratoplasty, Descemet membrane endothelial keratoplasty, Descemet stripping endothelial keratoplasty, cross linking, pre-Descemet's layer, Rho-associated kinase, keratoprosthesis, infectious keratitis, corneal dystrophy, corneal astigmatism, and keratoconus.

RESULTS

This review summarizes relevant and innovative original articles, review articles, and novel techniques from the following journals: American Journal of Ophthalmology, British Journal of Ophthalmology, Cornea, Graefe's Archive for Clinical and Experimental Ophthalmology, Investigative Ophthalmology & Visual Science, JAMA Ophthalmology, Journal of Cataract and Refractive Surgery, Journal of Refractive Surgery, and Ophthalmology. Case reports, abstracts, letters to the Editor, and unpublished work were excluded, as well as articles e-published ahead of print in 2012 that were discussed in the previous review. One hundred twenty-seven articles met the criteria for this review.

CONCLUSIONS

This review summarizes significant cornea-related literature from 2013.

Collagen cross-linking of the Boston keratoprosthesis donor carrier to prevent corneal melting in high-risk patients

OBJECTIVE

To examine the clinical relevance and pathophysiology of Boston keratoprosthesis (B-KPro)-related corneal keratolysis (cornea melt) and to describe a novel method of preventing corneal melt using ex vivo crosslinked cornea tissue carrier.

METHODS

A review of B-KPro literature was performed to highlight cases of corneal melt. Studies examining the effect of corneal collagen cross-linking (CXL) on the biomechanical properties of corneal tissue are summarized. The use of crosslinked corneal tissue as a carrier to the B-KPro is illustrated with a case.

RESULTS

Corneal melting after B-KPro is a relatively rare event, occurring in 3% of eyes during the first 3 years of postoperative follow-up. The risk of post-KPro corneal melting is heightened in eyes with chronic ocular surface inflammation such as eyes with Stevens-Johnson syndrome and mucous membrane pemphigoid. This chronic inflammation results in high tear levels of matrix metalloproteinases, the enzymes responsible for collagenolysis and corneal melt. Crosslinked corneal tissue has been shown to have stiffer biomechanical properties and to be more resistant to degradation by collagenolytic enzymes. We have previously optimized the technique for ex vivo corneal CXL and are currently studying its impact on the prevention of corneal melting after B-KPro surgery in high-risk eyes. Crosslinked carrier tissue was used in a 52-year-old man with familial aniridia and severe post-KPro corneal melt. The patient maintained his visual acuity and showed no evidence of corneal thinning or melt in the first postoperative year.

CONCLUSION

Collagen crosslinking was previously shown to halt the enzymatic degradation of corneal buttons ex vivo. This study demonstrates the safety and potential benefit of using crosslinked corneal grafts as carriers for the B-KPro, especially in eyes at higher risk of postoperative melt.