Limbal stem cell graft technique

New transplant approach may reduce risk of conjunctivalisation.Roibeard Ó hÉineacháin reports

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A new limbal stem cell transplant (LSCT) technique employing vacuum-dried amnion and fibrin glue to redirect conjunctival epithelium from encroaching on the cornea during re-epithelialisation appears to be a safe and effective technique for eyes with total limbal stem cell deficiency (LSCD), reported Darren Shu Jeng Ting MBChB FRCOphth at the 25th ESCRS Winter Meeting. “This limbal stem cell transplantation technique serves as an effective ocular surface reconstruction technique in managing total LSCD and improving vision, said Dr Ting, who is currently a Medical Research Council / Fight for Sight Fellow at the Queen’s Medical Centre, Nottingham, UK. The retrospective, interventional case series study included 10 eyes of 10 patients with a mean age of 46.2 years who were diagnosed with total LSCD. Causes of LSCD were chemical eye injury (30%), congenital aniridia-related keratopathy (30%), ocular surface malignancy (20%), Steven-Johnson syndrome (10%), and contact lens overuse (10%). All procedures were performed by Prof Harminder S Dua.All eyes underwent a modified form of the amnion-assisted conjunctival epithelial redirection (ACER) procedure, a technique first described by Prof Dua at Queen’s Medical Centre, Nottingham, UK, in 2017 as a means of preventing re-conjunctivalisation of the cornea after LSCT. After mean follow-up duration of 21.4 months, 60% of eyes had a complete corneal epithelialisation without conjunctivalisation and 20% had a complete epithelialisation but with partial conjunctivalisation sparing the visual axis. The remaining 20% were treatment failures, defined as conjunctivalisation not sparing the visual axis. The mean time to complete corneal re-epithelialisation was 1.14 months. Corrected distance visual acuity improved in 70% of eyes. Corrected distance visual acuity improved from 1.53 logMAR to 0.23 logMAR (p=0.004). The success rate was significantly higher among the 50% of patients receiving autologous grafts compared to those receiving allogeneic grafts (p=0.048). The original ACER technique involves removing fibrovascular pannus from the diseased cornea then performing a 360-degree peritomy and suturing the graft tissue in place at 12 and six o’clock. Then a small amniotic membrane is placed on the cornea and a large amniotic membrane is draped over the cornea and sutured into place with the peripheral conjunctiva. The new version of the technique involves using vacuum-dried amnion (Omnigen), instead of cryopreserved amnion, and fibrin glue instead of sutures, Dr Ting explained. The fibrin glue acts as a physical barrier for conjunctival cells and when they start to grow after dissolution of the fibrin, they are re-directed on to the amnion graft preventing admixture with limbal-explant derived cells. The amnion sheet was removed at two-to-four weeks postoperatively. “Vacuum-dried amnion has the advantages of being used off-the-shelf and of having higher transparency, allowing a better visualisation of the corneal healing postoperatively. The use of fibrin glue, instead of sutures, helps shorten intraoperative time and obviates suture related complications and the need for suture removal postoperatively,” he added. Darren Ting: ting.darren@gmail.com