Transcript Cost-Effectiveness of the Type I Boston Keratoprosthesis

The Role for Ipsilateral Autologous
Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
Jared D. Ament, MD, MPH, Yonas Tilahun, MD,
Eiman Mudawi, MD, Roberto Pineda, MD
1Massachusetts
Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA; 2Menelick
II Hospital, Addis Ababa University, Addis Ababa, Ethiopia;
3Makkah Eye Complex, Makkah Ophthalmic Technical College, Al-Rayad,Khartoum, Sudan
FINANCIAL DISCLOSURE: Some of the authors of this poster have received
research funding and travel expense reimbursement from Dr. Dohlman’s
Keratoprosthesis research fund. Dr. Dohlman nor do any of the authors
receive any financial benefit from the sale of the Boston Keratoprosthesis.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
PURPOSE:
To report the use of the Boston Keratoprosthesis (KPro)
with ipsilateral autologous corneas in 4 eyes of 3 patients
in Ethiopia and Sudan.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
INTRODUCTION:
Currently, surgery with the KPro is performed using an allograft donor
cornea, sandwiched between two polymethlmethacrylate (PMMA)
plates during assembly. Autologous corneas have been used with the
Cardona “nut and bolt” prosthesis1, but to our knowledge, no reports
on its use with the Boston KPro exist. This approach is especially
important in non-industrialized nations, where the availability of
corneal allograft tissue, operational costs, and high corneal graft failure
rates remain significant challenges. Ipsilateral autologous corneas
would make the KPro more accessible in these regions. Even without a
formal cost-effective analysis, the savings are markedly apparent.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
METHODS:
Specific patient selection criteria in non-industrialized nations are
outlined in the International Boston KPro Protocol2. Additional
requirements exist when considering autologous grafts. Patients were
not appropriate candidates for anterior lamellar keratoplasty due to
severely scarred lids or full-thickness central corneal scars.
Inclusion Criteria:
-Bilateral blindness per WHO3
-Clinically normal peripheral endothelium by specular reflection
-Limited stromal thinning after trephination (<30%)
Exclusion Criteria:
-Uncontrolled glaucoma
-Extensive anterior synechiae
-Evidence of corneal perforation.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
METHODS:
All patients received an aphakic KPro with a 16-hole PMMA
backplate and titanium- locking ring assembled around a 8.5mm
trephinated ipsilateral autologous cornea. An ECCE was performed
on all patients through the corneal trephination opening. Five to 20
month postoperative data is reported, including compliance, visual
outcomes, complications, and results from quality of life (QOL)
surveys. Disabilities in activities of daily living (ADL) were evaluated
by interview, using standardized scales.4 The Human Studies
Committee at the Massachusetts Eye and Ear Infirmary granted a
waiver of informed consent and HIPPA authorization for medical
record review.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
RESULTS:
Surgery in three eyes was uneventful. In one eye, intraoperative vitreous
loss was effectively managed with Wek-cel vitrectomy. Patient
characteristics and follow-up data are presented in table 1. Corneal
pathologies included advanced ocular trachoma and previous measles
keratitis. Uncorrected visual acuity improved in 100% of the eyes. All
patients adhered to the protocol, retained their contact lenses, and
successfully administered their medications. Based on a culturally
sensitive VF-14 survey5, patients experienced substantial improvement
in ADLs, such as regaining the ability to wash clothes and manage
transportation needs.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
DISCUSSION:
There has been growing global interest in the use of KPro for the
treatment of corneal conditions not effectively treated by penetrating
keratoplasty. Despite this, and the overwhelming incidence of blindness
due to corneal pathology, the use of KPro in non-industrialized countries
remains equivocal and rare. The use of ipsilateral autologous cornea as
the skirt in transplantation of the KPro mitigates costs and eliminates
corneal allograft storage. This also avoids graft rejection and allocates
available donor corneal tissue for suitable keratoplasty patients.
Concerns regarding the postoperative management and complications of
international KPro surgery include: inadequate follow-up, poor
compliance, infection, contact lens loss, retro-prosthetic membrane
formation, glaucoma, retinal detachment, and extrusion.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
DISCUSSION:
Nevertheless, in our small sample of ipsilateral autologous KPro
recipients, retention is 100% without postoperative complications, and
vision improved in all patients to ≥ 20/60. There are inherent
weaknesses with this report. We discuss a small sample with limited
postoperative follow-up. Many common complications, such as glaucoma
and endophthalmitis, often manifest later in the postoperative period.
Additional follow up will help elucidate the long term success of this
procedure. In summary, the use of ipsilateral autologous corneas for
assembly of the KPro in certain populations appears feasible and also
practical and cost saving as shown in this small group of patients from
non-industrialized countries with limited resources.
The Role for Ipsilateral Autologous Corneas as a Carrier for the Boston
Keratoprosthesis: The Africa Experience
REFERENCES:
1) Cardona H. Mushroom transcorneal keratoprosthesis (bolt and nut). Am J Ophthalmol. 1969
Oct;68(4):604-12.
2) Jared D. Ament, Roberto Pineda, Bryan Lawson, Irmgard Behlau, Claes Dohlman. The Boston
Keratoprosthesis: International Protocol. Version 2: June 2009.
http://www.masseyeandear.org/gedownload!/KPro%20International%20Protocol2.pd
f?item_id=5816015&version_id=5816016Blindness.
3) The World Health Organization. Available at: http://www.who.int/topics/blindness/en/. Accessed
on June 16, 2009.
4) Katz S, Ford AB, Moskowitz RW, Jackson BA, Jaffe MW. Studies of Illness in the aged. The index of
ADL: A standardized measure of biological and psychosocial function. JAMA. 1963 Sep 21;185:914-9
5) Boisjoly H, Gresset J, Fontaine N, Charest M, Brunette I, LeFrançois M, Deschênes J, Bazin R,
Laughrea PA, Dubé I.Am J Ophthalmol. The VF-14 index of functional visual impairment in candidates
for a corneal graft.1999 Jul;128(1):38-44.
6) Aldave AJ, Kamal KM, Vo RC, Yu F.The Boston type I keratoprosthesis: improving outcomes and
expanding indications.Ophthalmology. 2009 Apr;116(4):640-51