Clinical efficacy of a new surgical technique of oral mucosal epithelial transplantation for severe ocular surface disorders

Abstract

Background: Severe ocular surface disorders are one of the major blinding diseases, and a paucity of original tissue obscures successful reconstruction. We developed a new surgical technique of direct oral mucosal epithelial transplantation (OMET) to reconstruct severely damaged ocular surfaces in 2011. This study elaborates on the clinical efficacy of OMET.

Methods: A retrospective review of patients with severe ocular surface disorders who underwent OMET from 2011 to 2021 at the Department of Ophthalmology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine was conducted. Patients who were followed up for at least 3 months postoperatively and had sufficient pre or postoperative records were included. Surgical efficacy was evaluated by comparing the best-corrected visual acuity (BCVA), corneal transparency, neovascularization grade, and symblepharon grade. Additionally, postoperative ocular surface impression cytology was used to study the morphology of the newborn epithelial cells.

Results: Forty-eight patients (49 eyes; mean age: 42.55 ± 12.40 years, range:12-66 years) were enrolled in the study. The etiology included chemical burns (30 eyes), thermal burns (16 eyes), explosive injuries (1 eye), Stevens-Johnson syndrome (1 eye), and multiple pterygiums (1 eye). The mean follow-up period was 25.97 ± 22.99 months. Postoperatively, 29 eyes (59.18%) showed improved corneal transparency, 26 eyes (53.06%) had improved BCVA, 47 eyes (95.92%) had a stable epithelium until the final follow-up, 44 eyes (89.80%) had a reduced neovascularization grade. Of the 20 eyes with preoperative symblepharon, 15 (75%) were completely resolved, and five (25%) were partially resolved. Impression cytological studies showed no postoperative conjunctival invasion onto the corneal surface.

Conclusions: OMET is a safe and effective surgical technique for reconstruction in severe ocular surface disorder by maintaining a stable epithelium and reducing the neovascularization and symblepharon grade.

Keywords: Limbal stem cell deficiency; Ocular surface disorder; Oral mucosal epithelia; Symblepharon.

Fig. 1

The surgical procedures of OMET. A: Subconjunctival injection of saline. B: Removal of the fibrovascular tissue to expose the sclera and corneal surface. C: Placement of the cryo-AM and suturing. D: Harvesting of the oral mucosa graft from the lower lip. A double-ring incision (black circle) was made, and the mucosa between the two circles was harvested. E: Shaving off the subepithelial tissue. F and G: Suturing the graft onto the cryo-AM in the limbus area. H: Suturing the other side of the graft to the conjunctiva. I: Temporary suturing of the eyelids at the end of the surgery. OMET, oral mucosal epithelial transplantation; cryo-AM, cryopreserved amniotic membrane

Fig. 2

Grading neovascularization in the eyes. A: Grade 0, no invasion of the cornea; B: Grade 1, peripheral invasion of the cornea (black arrows), 1 to 2 mm inside the limbus; C: Grade 2, mid-peripheral invasion; D: Grade 3, invasion of the entire cornea

Fig. 3

Pre- and postoperative slit-lamp photographs for four patients with symblepharon. A1, B1, C1, and D1 are preoperative photographs showing grades I, II, III, and IV symblepharon, respectively. A2, B2, C2, and D2 were taken 14 months, 8 months, 3 months, and 12 months, respectively, after surgery for patients A, B, C, and D. A2 has no symblepharon, B2 and C2 show grade I symblepharon, and D2 shows grade II symblepharon Patient A was a 56-year-old man, whose left eye was damaged by chemical burn. The oral mucosa graft was transplanted at the nasal half part of limbus as the yellow line shown in A2. The neovascularization (NV) in the non-operated area (A1, black arrows) were no longer seen after surgery (A2)

Fig. 4

BCVA measured before and after surgery (at the last follow-up). Twenty-six cases (53.06%) showed improved BCVA after surgery and the rest remaining showed no change. BCVA, best-corrected visual acuity; LP, light perception; HM, hand movement; CF, count finger

Fig. 5

Ocular surface changes after surgery A-C: In a 26-year-old male patient diagnosed with SJS. A: Preoperative ocular surface status. B: One month after OMET, the corneal surface epithelization had not been completed, and intensive tiny NV occurred. C: Seven months after OMET, corneal surface epithelization was completed, and the NV was diminished D-F: In a 40-year-old male patient sustaining a chemical burn. D: Preoperative ocular surface status. C: One month after OMET, the corneal surface epithelization had not been completed yet F: Six months after OMET, epithelization had been completed and the patient had a better cornea transparency compared to picture E SJS, Stevens-Johnson syndrome; OMET, oral mucosal epithelial transplantation; NV: neovascularization

Fig. 6

Features of the postoperative corneal surface epithelia A-E: From a 48-year-old female patient who sustained thermal burns. A: Preoperative ocular surface status. B: At 45 days after the OMET, the corneal surface epithelization had completed and less NV compared to preoperative status. C: High-resolution OCT (Zeiss, Oberkochen, Germany) examination for the cornea at 45 days after OMET showed a thick epithelial layer (red arrows). D: Fluorescein staining of tear fluid showed a complete and smooth corneal epithelium, the dark stained (black arrows) part represents clusters of mucins adhering on the corneal surface. E: After washing with artificial tear drops, the mucins in picture D are no longer seen F-H: From a 57-year-old male patient who sustained a chemical burn. F: Preoperative ocular surface status. G: Three months after OMET, showing a semi-transparent corneal epithelium. H: Thirteen months after OMET, the corneal epithelium becomes thinner and more transparent than at three months

Fig. 7

IC studies for corneal epithelium after OMET. A, B: Slit-lamp photographs. C-I: PAS staining for corneal surface epithelium, photographed under light microscope A-D: From a 34-year-old male patient who sustained chemical burns. chemical burn. A: Preoperative status of the ocular surface. The trapezoid shows the filtering paper sample position for IC. B: Twelve days after surgery, the trapezoid shows that the IC examination was taken at the same position as the preoperative site. C: IC results for A, showing conjunctival epithelia cell features. D: IC result for B, 12 days after OMET. Cells at the mucosal graft position, at the limbus and the cornea surface position were morphologically different E-G: IC control pictures. E: Normal oral epithelia cells, taken from the patient himself. F: Normal conjunctival epithelial cells. G: Normal corneal epithelia cells. F and G were taken from the healthy eye of a 30-year-old male patient with unilateral chemical injury H-I: IC results for the eye in Fig. 6H. H: Showing epithelial cells in the peripheral corneal area, next to the limbus. There were a lot of PAS-positive substances in the cells (black arrows). I: Showing cells in the central corneal area, next to the pupil, where the epithelium was nearly transparent. There were fewer PAS-positive substances in cells Scale bars: C, 100 μm; D, 500 μm; E-I, 50 μm IC, impression cytology; OMET, oral mucosal epithelial transplantation; PAS, Periodic acid–Schiff