|Home | About | Journals | Submit | Contact Us | Français|
Amniotic membrane (AM) transplantation has been used successfully for the treatment of ocular surface diseases for several years.1,2,3 Indications for use of AM at the cornea include persistent epithelial defects, corneal ulcers and chemical burns.1,2,3 Surgical strategies for AM placement onto the cornea are suturing AM onto the corneal surface (“patch”), into a corneal defect (“graft”) or a combination of both strategies (“sandwich”).1,2,3,4,5
All published reports for use of AM in patients are based on the use of sutures. Although most patients can be treated with the suture‐based approach, there are several situations in which sutures should be avoided: patients under intensive care, long‐lasting corneal epithelial defects causing a cornea too thin to support sutures or sutures may be technically difficult to place in the case of a previous graft, and, in addition, sutures can induce scarring and neovascularisation.6 Since the beneficial effects of AM are at least partially mediated by agents released from AM and by AM acting as a natural bandage contact lens,1,2,3,4,5 we reasoned that an AM‐covered “bio‐onlay” may have the same beneficial effects as a sutured graft while avoiding the detrimental effects of sutures. Here we describe a novel sutureless technique using AM to treat persistent corneal epithelial defects.
First, a novel technique for the coating of Illig shells (Müller & Söhne, Wiesbaden, Germany) with AM (bio‐onlays) was developed. Initially, the correct size of the Illig shell was determined for each patient (fig 1A1A).). Next, under sterile conditions in the operating room, a sheet of freeze‐stored AM (2.5×3.5 cm) was placed around the Illig shell and secured using 8‐0 vicryl sutures (fig 1B1B).). The epithelial side of the AM was placed outwards. Suturing takes more time compared with placing just a single AM patch. Finally, the AM‐covered bio‐onlay was placed onto the eye of the patient using topical anaesthesia (fig 1C1C).). AM‐covered bio‐onlays were left in place for 2 weeks under topical treatment with lubricants, antibiotics and serum eye drops. After 2 weeks, the device was removed at the slit‐lamp examination using topical anaesthesia.
This technique was used in two patients with persistent epithelial defects (after prior informed consent): a 36‐year‐old patient with neurotrophic keratopathy after keratoplasty (fig 1D1D)) and a 28‐year‐old woman with chronic graft‐versus‐host disease. Both defects had not healed with intensive topical treatment, including serum eye drops for several weeks (8 and 6 weeks, respectively). In both patients, AM‐covered bio‐onlays were tolerated well. When removed after 2 weeks, AM covering the surface was intact and the persistent epithelial defects were completely healed (fig 1E1E).). There was no evidence for induction of corneal angiogenesis due to the device.
To study the integrity of AM, the membrane was fixed and subjected to histological examination: as can be seen in fig 2A2A,, the AM covering the Illig shell was well preserved (fig 2B2B).). Epithelium and basement membrane of AM appeared intact (fig 2C,D2C,D).). Using immunohistochemical analysis with CD45 as panleucocyte and CD68 as macrophage marker (Dako, Hamburg, Germany),6 we ruled out a significant accumulation of inflammatory cells on the surface of or within the bio‐onlay (fig 2E,F2E,F).). This lack of inflammatory cell “trapping” within the AM‐covered bio‐onlay is in contrast with previous observations made with AM layered directly onto inflamed corneas,7 and may be due to (1) only partial direct contact of the bio‐onlay with the ocular surface and (2) lack of an inflammatory, chemotactic stimulus within the bio‐onlay attracting inflammatory cells in contrast with the scenario of an AM placed onto an inflamed corneal stroma.7
In summary, we demonstrate a novel sutureless method of application of AM onto the ocular surface using AM‐covered bio‐onlays. A small pilot study provides proof of concept and demonstrates that the technique was well tolerated. AM‐covered bio‐onlays seem to be beneficial because they act as a natural bandage contact lens and, in addition, exert trophic and anti‐inflammatory effects. More patients will have to be studied under controlled conditions to further evaluate this promising new technique. Our pilot study paves the way towards non‐surgical use of AM components for surface reconstruction and for anti‐inflammatory/antiangiogenic treatment.6,8
Funding: Interdisciplinary Center for Clinical Research (IZKF) Erlangen (A9), ELAN Fonds (AZ: 05.06.04.1).
Competing interests: None declared.