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CASE REPORT
Year : 2023 | Volume
: 13
| Issue : 1 | Page : 101-105
Severe ocular alkali injury managed with an externally sutured amniotic membrane and customized symblepharon ring
Sophia S Lam1, Bonnie A Sklar2, Marisa Schoen2, Christopher J Rapuano3
1 Department of Medical Education, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
2 Department of Ophthalmology, Wills Eye Hospital, Philadelphia PA, USA
3 Department of Ophthalmology, Wills Eye Hospital; Cornea Service, Wills Eye Hospital, Philadelphia, PA, USA
Correspondence Address:
Dr. Christopher J Rapuano
Department of Ophthalmology, Wills Eye Hospital, 840 Walnut Street, Suite 920, Philadelphia, PA 19107
USA
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/2211-5056.362597
Alkali injuries are ocular emergencies that require immediate evaluation and therapy to preserve vision. Severe alkali injuries can result in long-term vision-threatening sequelae including symblepharon, corneal ulceration, corneal scarring, limbal stem cell deficiency, xerophthalmia, cicatricial changes of the eyelid and adnexa, glaucoma, uveitis, and permanent vision loss. Treatment is aimed at neutralizing the pH, controlling inflammation, and restoring the ocular surface. Here, we present the case of a 35-year-old male who sustained direct ocular exposure to sodium hydroxide, resulting in significant corneal and conjunctival epithelial defects despite aggressive initial medical therapy. The patient subsequently received a large, externally sutured amniotic membrane (AM) with a customized symblepharon ring to promote healing. The corneal and conjunctival defects resolved, and at 4 months after the initial injury, the patient's visual acuity had improved to 20/25. Clinicians should be aware of the various surgical techniques to place an AM transplantation and identify the best strategy based on clinical findings and the extent and severity of the injury.
Keywords: Ocular alkali injury, ProKera, surgical technique, sutured amniotic membrane transplantation
Ocular chemical injuries are vision-threatening ocular emergencies that require immediate evaluation and management by an ophthalmologist. Male patients between 20 and 40 years of age make up the highest-risk demographic for ocular chemical injuries.[1] One study found that 56.6% of ocular chemical exposures occurred in men, with a median age of 32 years.[2] Exposures may occur in a variety of locations such as industrial chemical laboratories, construction sites, and machinery factories.[1] Alkali chemical injuries are considered more harmful than acid injuries because the former can penetrate deeper into tissue due to their lipophilic nature.[1] acid injuries cause tissue protein denaturing and precipitation, creating a barrier on the ocular surface and limiting tissue penetration compared to alkali injuries.[1]
Chemical injuries can be challenging to manage due to the involvement of multiple ocular tissues, including the surface epithelium of the cornea and conjunctiva, limbal stem cells, corneal stroma, endothelium, and anterior segment structures. Even with immediate irrigation and medical treatment, chemical exposures can result in symblepharon, corneal ulceration, corneal scarring, limbal stem cell deficiency, xerophthalmia, cicatricial changes of the eyelid and adnexa, glaucoma, uveitis, and permanent vision loss.[1] The standard of care is immediate, continuous irrigation with normal saline or lactated Ringer's solution until the pH has been neutralized to the physiologic range. Medical therapy includes the use of topical antibiotics, topical steroids, cycloplegic agents, oral doxycycline, and Vitamin C. For more severe injuries, amniotic membrane transplantation (AMT) may be applied using various techniques. AMT is an ideal material for ocular surface reconstruction due to its epithelial wound-healing properties.[3] transparency, anti-inflammatory, antifibrotic, and anti-angiogenic properties. In this report, we describe the use of a large sutured AMT with a customized symblepharon ring made from intravenous (IV) tubing to manage the acute phase of a severe alkali injury.
Case ReportA 35-year-old male presented with pain and blurred vision after a solution containing sodium hydroxide splashed into his left eye while power-washing wood. He immediately irrigated the eye with hose water for approximately 30 min and subsequently removed a contact lens from the affected eye.
On initial evaluation in the Emergency Department, he was found to have a pH of 7.5 in the upper fornix and 7.8 in the lower fornix of the affected eye. He was immediately irrigated with 2 L of normal saline with neutralization of the pH. His ophthalmologic examination revealed visual acuity of 20/20 in the unaffected right eye (OD) and 20/70 pinhole to 20/25 in the affected left eye (OS). He was found to have 2+ conjunctival injection and chemosis with sloughing of the inferonasal and temporal conjunctival epithelium OS. There was a central corneal epithelial defect (KED) that measured approximately 1.5 mm × 1.5 mm and diffuse 2+ stromal edema. Examination of the right eye was normal. Intraocular pressures (IOPs) were normal. The patient was discharged to home with instructions to use prednisolone acetate 1% ophthalmic drops every 2 h, ofloxacin four times daily, cyclopentolate 1% twice daily, doxycycline 100 mg twice daily, and Vitamin C 1 g daily.
The following day, the patient's visual acuity had decreased to 20/150 pinhole 20/50 OS. The exam showed 3+ conjunctival chemosis, extensive staining of the bulbar and palpebral conjunctiva, diffuse sloughing of the conjunctival epithelium, and four clock hours of perilimbal whitening OS [Figure 1]. The KED was larger (8 mm × 6 mm) and there was persistent diffuse 1 + stromal edema with Descemet's folds. The upper and lower eyelids were edematous with incomplete closure due to significant prolapsing chemosis.
Figure 1: Postchemical injury day 1: conjunctival chemosis, extensive bulbar, and palpebral conjunctival staining, diffuse sloughing of the conjunctival epithelium, and four clock hours of perilimbal whitening inferiorlyGiven the diffuse involvement of both the bulbar and palpebral conjunctiva, the patient was taken to the operating room that evening for the placement of a large 5 cm × 10 cm externally sutured AM with a customized symblepharon ring. After the eyelashes were trimmed, one edge of the AM was draped over the upper eyelid margin with the basement membrane side up and secured with a running 8-0 nylon suture. The remainder of the AM was draped over the cornea, conjunctiva, and inferior eyelid. A symblepharon ring large enough to press up against the fornices was fashioned from IV tubing. The symblepharon ring was carefully placed into the superior and inferior fornices on top of the AM ensuring it was properly oriented under the ring. After that, the inferior edge was secured to the lower eyelid margin with a running 8-0 nylon suture. To further secure the AM to the ocular surface, we used four 9-0 Vicryl mattress sutures to attach the AM to the episclera 2 mm from the limbus at the 3, 6, 9, and 12 o'clock positions.
On the 1st postoperative day, the AM was intact and the KED was grossly unchanged [Figure 2]. Postoperative medications included dexamethasone-neomycin-polymyxin B (Maxitrol) ointment every 2 hours, ofloxacin 0.3% drops four times daily, atropine 1% twice daily, doxycycline 100 mg twice daily, and Vitamin C 1 g once daily. Over the next few visits, the KED was noted to decrease in size, and the chemosis resolved. By the 3rd postoperative week, the AM had dissolved and slit-lamp examination showed resolved conjunctival staining, improved perilimbal whitening, and a smaller but persistent KED. In addition to the Maxitrol, erythromycin ointment four times a day was added. The eyelid sutures and symblepharon ring were removed and a ProKera Plus (TissueTech, Doral, Florida) was placed [Figure 3]. By postoperative month 2 and 4, the KED had resolved with mild residual central anterior stromal haze, there was minimal conjunctival scarring, and the patient's best-corrected visual acuity was 20/25 [Figure 4]. By postoperative month 4, the medication regimen included erythromycin ointment twice daily, timolol-dorzolamide drops twice daily for a prior IOP elevation, prednisolone acetate 1% drops four times daily, and preservative-free artificial tears four times daily.
Figure 2: Postoperative day 1: intact AMT draped over the eyelid margins with the symblepharon ring in place. Note the running nylon suture near the inferior eyelid margin. Although not well shown, four 9-0 Vicryl sutures also secured the AM to the episclera about 2 mm from the limbus at the 3, 6, 9, and 12 o'clock positions. AMT: Amniotic membrane transplantation
Figure 3: Postoperative week 3: dissolved AMT, persistent corneal epithelial defect, and resolved conjunctival staining. The externally sutured AMT and symblepharon ring were removed with subsequent placement of ProKera Plus (TissueTech, Doral, Florida). AMT: Amniotic membrane transplantation
Figure 4: Postoperative week 8: the corneal epithelial defect has completely resolved and the conjunctiva is quiet with minimal scarring. There is a mild resolving corneal haze Discussion Ocular alkali exposures can constitute a severe injury with potentially vision-altering, irreversible sequelae if not immediately and aggressively addressed. In one study, industrial accidents led to 61% of ocular alkali burns, 37% occurred at home, and the remainder originated from an unknown source.[4] Common sources of chemical injuries include sulfuric acid (battery acid and industrial cleaner), acetic acid (vinegar and glacial acetic acid), hydrochloric acid (chemical laboratories), sulfurous acid (bleach and food preservative), ammonia (fertilizer and refrigerant), lye (drain cleaner), and lime (plastic, mortar, and cement).[1] Alkali chemical exposures are considered more harmful than acid to ocular structures, as these compounds penetrate tissue barriers more readily due to their lipophilic nature. Acidic compounds generally lead to denaturing and precipitation of proteins that limit tissue penetration.[1]
Sequelae from chemical exposures may evolve over time. Immediately postexposure, common findings include corneal and conjunctival epithelial damage, corneal opacification, increased IOP, lens opacification, and perilimbal blanching indicative of ischemia.[1] The presence and degree of perilimbal blanching are one of the most significant prognostic indicators for poor corneal healing due to the loss of limbal stem cells responsible for regenerating the corneal epithelium. The subacute recovery period is characterized by a transition from acute ocular surface inflammation to chronic inflammation, stromal repair, and scarring.[1] Long-term ocular complications include symblepharon, corneal scarring, limbal stem cell deficiency, xerophthalmia, cicatricial changes of the eyelid and adnexa, glaucoma, uveitis, and cataract.[1] Adnexal abnormalities such as lagophthalmos, cicatricial ectropion or entropion, trichiasis, and ankyloblepharon may occur.[1]
The standard of care for chemical injuries includes immediate, copious irrigation with isotonic saline or lactated Ringer's solution to neutralize the pH before ophthalmic evaluation.[1] A complete dilated examination should be performed, but phenylephrine dilating drops should be avoided to prevent the risk of vasoconstriction and further ischemia.[5] Topical steroids, topical antibiotic drops, and topical cycloplegics are recommended, as well as oral doxycycline and Vitamin C to reduce proteolysis and inflammation.[1] Retinoic acid has also been shown to improve ocular surface disorders associated with goblet cell dysfunction.[1]
Cryopreserved AMT is a promising treatment for severe ocular alkali injuries. AM comes from the innermost placental membrane and contains a single-epithelial cell layer, thick basement membrane, and stroma.[3] The basement membrane supports host epithelial cell migration, adhesion, and differentiation while inhibiting epithelial cell apoptosis. The stroma contains cytokines, growth factors, and protease inhibitors that promote anti-inflammatory, antifibrotic, anti-angiogenic, and antimicrobial effects.[3] As a result, the AM can suppress inflammation, promote epithelial growth, and help prevent potentially vision-threatening complications of chemical injuries.
In addition to ocular alkali injuries, AMT has various indications in corneal surface disorders.[3] AMT has been employed to treat thermal burns, Stevens–Johnson syndrome with ocular involvement, corneal ulceration, symptomatic bullous or band keratopathy, pterygium excisions, and conjunctival and ocular surface tumors.[3] Prior studies have shown better visual outcomes with AMT placement in acute chemical burn cases compared with chronic cases.[6],[7],[8] In one study of patients with ocular chemical or thermal burns, the overall success rate with AMT was 87.5% in the acute group (<1 month of injury) and 73% in the chronic group (>1 month) in terms of ocular surface reconstruction, healing of epithelial defects, improving limbal stem cell function and symptomatic relief.[8] In another study, patients with AMT placement within 5 days of an ocular chemical or thermal injury had faster epithelial healing compared to the patients who received AMT after 5 days and the control group.[7] Multiple studies have shown that eyes with acute ocular burns and AMT placement in the acute phase have greater epithelization healing, corneal vascularization, and improved visual acuity compared to AMT patching in the chronic phase.[6],[7],[8],[9],[10],[11],[12],[13]
AMTs can be secured to the ocular surface through several approaches. The AM may be sutured to the eyelid only and draped over the conjunctiva and cornea or sutured directly to the conjunctiva. Sutureless AMT may be performed with fibrin or cyanoacrylate glue in isolation or in combination with sutures. Overall, multiple studies have shown similar long-term visual outcomes between sutured and glued AMT.[14],[15] The AM may be oriented with the basement membrane side facing upward, such that the stromal surface faces the patient's cornea, and provides a substrate for the growth of corneal and conjunctival epithelial cells. The alternative is to place the AMT with the basement membrane side facing down, such that the stromal AM faces the patient's eyelids.[3] The stromal AM can entrap and induce the apoptosis of inflammatory cells, which reduces the inflammatory response when facing the patient's eyelids.[3]
A ProKera is a self-retaining alternative to the traditional AMT based on a dual polycarbonate ring system that acts as a small symblepharon ring to support the AM.[16] The indications for ProKera overlap with those for AMT and include a variety of corneal surface disorders, particularly neurotrophic keratopathy.[16] An advantage of ProKera is that it may be placed easily in a clinic setting, whereas AMT placement generally requires sedation and an operating room with associated costs, staffing, and time. However, ProKera covers only the cornea and perilimbal conjunctiva, whereas sheets of AMT may additionally cover the full extent of the bulbar conjunctiva, palpebral conjunctiva, and fornices.[16] The traditional AMT technique includes multiple discrete sheets that may be sutured or glued together, thereby providing greater coverage, although gaps may exist between pieces.[16]
In our case, we placed an externally sutured single 8-0 nylon suture on each eyelid, a large 5 cm × 10 cm sheet of AM, and a customized forniceal ring made with IV tubing. The symblepharon ring was made from sterile IV tubing [Figure 5]. The length of IV tubing was estimated by measuring the distance between the patient's upper and lower fornices and calculating the circumference of the circle (diameter × π) plus ~5 mm to account for the overlap of the tubing ends. One end of the IV tubing was cut with a straight edge and dilated with closed scissors, and the other end was cut with a tapered end and inserted into the straight edge using hemostats. The tubing was trimmed to adjust the size of the symblepharon ring and ensure that it was fully expanded in the fornices without causing lagophthalmos.
Figure 5: a. Construction of symblepharon ring using sterile IV tubing. b. The diameter of the ring was ~30 mm. IV: IntravenousA similar technique has been described by Ma et al. in the setting of acute Stevens–Johnson syndrome.[17] To date, there have been no published reports in the literature describing the use of this technique to treat severe alkali chemical injuries.[17] Compared with suturing multiple juxtaposed pieces together, using the large sheet of AM maximizes coverage of the affected ocular surface, may better prevent cicatrization of opposing ocular surfaces, and may result in fewer ocular complications such as temporal symblepharon.[17] Anchoring the membrane to the external skin of the upper and lower eyelids and holding the AM in place with the IV tubing eliminated the need for conjunctival suturing. In our case, decreasing manipulation of the AM and friable conjunctiva during placement greatly reduced operative time, led to decreased intraoperative bleeding, and eliminated susceptibility for bacterial superinfections at puncture sites. Shanbhag et al. further demonstrated that a similar procedure can be performed with cyanoacrylate glue rather than external skin sutures.[18] The use of readily available, low-cost IV tubing allowed for adjustment of the ring diameter to ensure the ring was appropriately sized for the patient's fornices. Our patient tolerated this procedure well and significantly improved in terms of visual acuity and ocular surface as described.
Overall, AMT can be effective in promoting re-epithelization and controlling inflammation in acute alkali injuries. The specific orientation and technique of applying the AM should be tailored to each patient based on the indication and degree of severity. Further studies with larger patient populations should be conducted to better characterize differences in outcomes between the various AMT techniques.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Acknowledgments
Financial support and sponsorship
Nil.
Conflicts of interest
The authors declare that there are no conflicts of interest of this paper.
References
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