Dr.(Lt Col) Alok Sati, Dr.(Brig) Parthasarathi Moulick,Dr.Jaya Kaushik,Dr.(maj) Shankar Sandeep
Introduction:
Simple Limbal Epithelial Transplantation (SLET) is a surgical technique first described by Dr Sangwan in 2012, 1 for patients with unilateral limbal stem cell deficiency (LSCD). Traditionally, in this technique, the limbal pieces from the contralateral eye are placed over the amniotic membrane (AM) and made adhered to with the fibrin glue. However, in children, the potential of dislodgement of limbal pieces is more as compared to adults. Hence, we modified the traditional technique by placing the limbal pieces underneath the AM in order to prevent their inadvertent dislodgement. Herein, we report two cases, successfully managed by the modified technique.
Methods:
Case 1: 5-years-old male, presented with history of fall of ‘chuna’ in right eye (RE) while playing about eight months ago. Initial ocular examination revealed best corrected visual acuity (BCVA) as 3/60 in RE (less visual acuity due to irregular astigmatism) and 6/6 in left eye (LE). RE examination showed superior symblepharon involving approximately 2 clock hours of limbus. Conjunctivalisation with vascularisation was present in almost superior 1/3rd of cornea. Rest of the RE examination was within normal limits. Left eye examination revealed no abnormality. The patient was diagnosed as a case of partial LSCD RE. In view of affection of visual acuity, the child was undertaken for symblepharon release and SLET under general anaesthesia in RE. One clock hour of limbus along with the adjacent conjunctiva (CAG) was obtained from the superotemporal aspect of the contra lateral eye. CAG was used to cover the bare sclera after release of symblepharon. Pannus was removed from the affected eye followed by placement of limbal stem cells contained limbal pieces (prepared from 1 clock hour of limbus from the contra lateral eye) at the affected site. AM was subsequently placed over the limbal pieces and made adhered with the fibrin glue. Bandage contact lens (BCL) was then subsequently applied.
Case 2: 10-years-old male, presented with history of fall of ‘chuna’ in left eye (LE), again while playing about eleven months ago. Initial ocular examination revealed best corrected visual acuity (BCVA) as 6/6 in RE and 6/36 (less visual acuity due to irregular astigmatism and superficial corneal scar) in left eye (LE). RE examination was within normal limit. LE examination showed conjunctivalisation with vascularisation almost at nasal 1/2 of cornea including inferior periphery from 5 to 8 o’clock hour positions. The patient was diagnosed as a case of partial LSCD LE. In view of affection of visual acuity, the child was undertaken for SLET under general anaesthesia in LE. One clock hour of limbus was obtained from the superotemporal aspect of the contra lateral eye. Pannus was removed from the affected eye followed by placement of limbal stem cells contained limbal pieces (prepared from 1 clock hour of limbus from the contra lateral eye) at the affected site. AM was subsequently placed over the limbal pieces and made adhered with the fibrin glue. Bandage contact lens (BCL) was then subsequently applied.
Results:
Both the patients were reviewed on postop day 1, 7, 28 and every month till six month. In donor eye, topical steroid (started 4 times/day) was weekly tapered. Topical antibiotic was administered till the epithelial defect healed. In recipient eye, topical steroid (started 6 times/day) was monthly tapered. Topical antibiotic was administered till the epithelial defect was noted. BCL was removed once the epithelium stabilised in the recipient eye.
Case 1: At 6 month, BCVA was 6/9 (p) in RE. There was no recurrence of symblepharon. Ocular movement was full and free in downgaze. Ocular surface is healthy with no recurrence of pannus.
Case 2: At 6 month, BCVA was 6/12 in RE (Less BCVA due to central corneal scar). Ocular surface is healthy with no recurrence of pannus.
Discussion:
Lime injury is the most common cause of unilateral LSCD in India and is invariably manifested by the classic triad i.e. conjunctivalisation, vascularisation and inflammation of cornea. The treatment strategies for unilateral LSCD include conjunctival limbal autograft (CLAG), cultivated limbal epithelial transplantation (CLET) and SLET. SLET was developed to address the limitations of other techniques, 2 i.e. the technical difficulty of ex-vivo expansion of cells in CLET (require expensive laboratory facilities) and the larger amount of valuable limbal tissue harvested in CLAG (potential for creating LSCD at donor site). The current report highlights the successful outcomes of SLET in children with modifications.
In routine SLET, limbal pieces are placed over the amniotic membrane which serves as a medium for proliferation of the progenitor cells. In modified technique, the limbal pieces are placed underneath the amniotic membrane. Hence the stromal surface acts as a medium on which the progenitor cells proliferate. However, amniotic membrane provides a conducive niche for progenitor cells to proliferate by its anti-inflammatory property. In addition, amniotic membrane prevents the dislodgement of limbal pieces especially in children.
The current report is unique in many aspects. First, the modified technique of SLET has been reported for the first time. Second, this technique provides evidence that progenitor cells can even proliferate on corneal stroma with a successful outcome. Though the sample size of the current report is extremely less, more such studies with a larger sample size is required in future to validate the results.
References:
- Sangwan VS, Basu S, MacNeil S, Balasubramanian D. Simple limbal epithelial transplantation (SLET): a novel surgical technique for the treatment of unilateral limbal stem cell deficiency. Br J Ophthalmol. 2012 Jul;96(7):931-4.
- Sangwan VS, Sharp JAH. Simple limbal epithelial transplantation. Curr Opin Ophthalmol. 2017; 28:382-386.
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