SHORT TERM VISUAL OUTCOMES BOSTON KERATOPROSTHESIS TYPE I

Khalid M. Al-Arfaj, MDFatemah Al-Shamlan, MD Mohammed Hantera, MD

Financial Disclosure: NONE

Dammam University Dhahran Eye Specialist

Hospital

INTRODUCTION

• Clinical experience with keratoplasty over the past century showed that patients with Stevens-Johnson syndrome (SJS), ocular cicatricial pemphigoid (OCP), chemical burns, stem cell deficiencies, and severe vascularization have an extremely poor prognosis.1 In addition, patients with repeated graft failures also have poor likelihood of successful subsequent corneal allo-grafting.2

• Boston Keratoprosthesis (Massachusetts Eye and Ear Infirmary, Boston, MA) is the most commonly used keratoprosthesis.3• Our study was designed to evaluate the visual outcomes,

complications and retention of threadless type I Boston KPro. The snap-on threadless back plate facilitates easier intraoperative assembly and prevents any shredding of endothelium and descemet’s by the posterior plate screwing. To the best of our knowledge, such data has not been reported before in the Middle East.

• There are 2 variants of the device. Type I, the more common variant, is a collar button-shaped device with front plate (diameter 5.5–7.0 mm),3 a central optical stem, and a back plate (available in 8.5 mm diameter adult size and 7.0 mm diameter paediatric size),4 with eight holes that facilitate the nutrition and hydration of the corneal graft.5, 6

PATIENTS AND METHODS

• We undertook a retrospective analysis of 6 eyes of 6 patients (3 females and 3 males; age range: 48 to 72 years) who underwent Boston type I threadless keratoprosthesis implantation at a tertiary care eye hospital in Saudi Arabia by a single surgeon with similar surgical technique.

SURGICAL TECHNIQUE

• Standard surgical technique as described by Dohlman and Barnes was followed.8 • Donor cornea was trephined with a 3 mm trephine and

optical cylinder of the Kpro was passed through it. The back plate of the KPro was then snapped onto the stem with no rotating movement.• A titanium locking ring is finally snapped in place behind

the back plate to prevent loosening of the back plate. • The graft prosthesis combination is then transferred to the

patient’s trephined corneal opening and sutured with sixteen 10-0 monofilament nylon interrupted sutures.

• Finally, a soft contact lens (Kontur lens; Kontur Kontact Lens Co., Hercules, CA), 16 mm diameter and 9.8 mm base curve, plano power, is placed as a bandage lens.

• All patients received lifelong prophylactic antibiotics: gutt moxifloxacin 0.5% (Vigamox, Alcon Inc., Hunenberg, Switzerland), gutt Vacomycin fortified drops (25mg/ml) qid, gutt Prednisolone Acetate 1% (Predforte, Allergan, Inc. ,Irvine, CA, U.S.A.), and Tears Naturale Free (Alcon Inc., Hunenberg, Switzerland).

Pre Op. UCVA

Post Op. UCVA

Follow Up

1st Pt. HM HM 28 months

2nd Pt. CF Near face 20/50 22 months

3rd Pt. HM 20/80 20 months

4th Pt. LP 20/25 16 months

5th Pt. HM 20/60 5 months

6th Pt. HM 20/50 3 months

Results …

Results …

Retention Complication

1st Pt. No Graft melting required regular grafting

2nd Pt. yes None

3rd Pt. yes Retro prosthetic Membrane

4th Pt. yes None

5th Pt. yes None

6th Pt. yes None

• Careful follow-up for  patients with severe ocular surface disease with Boston Kpro is crucial for the long-term success and survival of the procedure.

• Boston Kpro has shown improved clinical results and decreasing complications.

• It has promising results especially in the category of non autoimmune patients but continued innovations and clinical trials are needed.

CONCLUSION

REFERENCES

1.Khan B, Dudenhoefer EJ, Dohlman CH. Keratoprosthesis: an update. Curr Opin Ophthalmol 2001;12(4):282-287.

2.Dunlap K, Chak G, Aquavella JV, Myrowitz E, Utine CA, Akpek E. Short-term visual outcomes of Boston type 1 keratoprosthesis implantation. Ophthalmology 2010;117(4):687-692.

3.Ilhan-Sarac O, Akpek EK. Current concepts and techniques in keratoprosthesis. Curr Opin Ophthalmol 2005;16(4):246-250.

4.Dohlman CH, Harissi-Dagher M. The Boston Keratoprosthesis: A New Threadless Design. Digital Journal of Opthalmology 2007 [Cited: August 05, 2010];13(3):[about 6 p.]. Available from: http://www.djo.harvard.edu/site.php?url=/physicians/oa/1055.

5.Dohlman CH, Dudenhoefer EJ, Khan BF, Morneault S. Protection of the ocular surface after keratoprosthesis surgery: the role of soft contact lenses. Clao J 2002;28(2):72-74.

6.Dudenhoefer EJ, Nouri M, Gipson IK, Baratz KH, Tisdale AS, Dryja TP, Abad JC, Dohlman CH. Histopathology of explanted collar button keratoprostheses: a clinicopathologic correlation. Cornea 2003;22(5):424-428.

7.Sayegh RR, Avena Diaz L, Vargas-Martin F, Webb RH, Dohlman CH, Peli E. Optical functional properties of the Bostonv Keratoprosthesis. Invest Ophthalmol Vis Sci 2010;51(2):857-863

8.Dohlman CH, Barnes S MJ. keratoprosthesis. In: Krachmer JH, Mannis MJ, Holland EJ, eds. Cornea, 2nd ed. St Louis, MO: Mosby–Year Book Inc., 2005.