Frozen Versus Fresh Corneal Carriers for the Boston KPro Type I Donor Carriers
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|ClinicalTrials.gov Identifier: NCT01950598|
Recruitment Status : Completed
First Posted : September 25, 2013
Last Update Posted : January 28, 2021
The purpose of this study is to determine whether frozen corneas are as safe and effective as fresh corneas for use as carriers with the Boston Keratoprosthesis type I (KPro) over long term follow-up.
Corneal transplantation is typically performed using fresh, transparent corneas. With KPro surgery, the corneal transplant only serves as a carrier to suture the KPro in place. The cornea used in KPro surgery does not need to be clear like a normal transplant. Frozen corneal tissue can be used to repair the cornea in cases of emergency but the tissue is not transparent and does not allow good vision. We hypothesize that frozen grafts are equivalent as fresh grafts when used as carrier for the KPro.
|Condition or disease||Intervention/treatment||Phase|
|Corneal Blindness Boston Keratoprosthesis Type I Candidate||Procedure: Boston KPro type I - fresh graft Procedure: Boston KPro type I surgery - frozen graft||Not Applicable|
The Boston Keratoprosthesis (KPro) is a collar-button shaped device made from a specialized clear plastic material. This device is used to replace a diseased and opaque cornea with a clear window so that vision can be improved. KPro surgery is an alternative to a traditional corneal graft and is used when a traditional corneal graft has failed or has a very poor probability of success.
During KPro surgery, the KPro needs to be incorporated into a corneal graft before it is sutured to the patient's cornea. The corneal graft serves as a support to the KPro and helps to re-establish vision. The corneas typically used as carriers for the KPro are fresh corneas provided through donors. These fresh corneas are also used in traditional corneal transplantation, without KPro implantation.
Due to shortage of fresh corneas in the province of Quebec, this project is interested in evaluating if corneas that have been previously frozen can act as carriers to the KPro. The frozen corneas cannot be used in traditional corneal transplantation surgery because they are not transparent. However, they can act as a support to the KPro, as in this case, it is the KPro and not the corneal graft that re-establishes vision. The use of frozen corneas for KPro surgery has the potential to improve access to corneal donor tissue and improve the wait-times for KPro surgery.
37 patients were be recruited from the Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital between October 2008 and November 2009. Participants were divided into 2 groups: the first group will receive a KPro in a fresh corneal carrier graft while the second group will receive a KPro in a frozen carrier graft. The use of a fresh or frozen corneal graft depended on the availability of fresh tissue on the morning of surgery. 19 patients received a fresh carrier graft and 18 received a frozen carrier graft.
Patients were followed on postoperative day 1, week 1 and 2, month 1, 3 and 6 and every 1 to 3 months thereafter up to 2 years. At each follow-up visit, a complete ophthalmological examination was performed, including best-corrected Snellen visual acuity and slit lamp assessment for leaks, tissue necrosis, melts, extrusion, inflammation, retroprosthetic membrane formation and infectious endophthalmitis.
The current study aims re-consent patients previously enrolled in this study to prospectively evaluate the long-term outcomes of KPro surgery using either a fresh or frozen carrier graft. IRB approval was obtained from the CHUM. Written informed consent from the concerned patients will be obtained for this extension study during their routine visits at the CHUM Ophthalmology department.
Patients in this study will continue their routine follow-up at the frequency determined by their surgeon, which may vary from every 3 to 6 months.
Outcome measures include surgical feasibility, level of preoperative and postoperative visual acuity (VA), retention of the device and complications as stated above. Outcomes will be compared at 5 and 10 years.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||37 participants|
|Intervention Model:||Parallel Assignment|
|Official Title:||Boston Keratoprosthesis Type 1 Surgery: Use of Frozen Versus Fresh Corneal Donor Carriers|
|Actual Study Start Date :||September 2013|
|Actual Primary Completion Date :||November 2020|
|Actual Study Completion Date :||November 2020|
Active Comparator: Fresh carrier graft for KPro
KPro implanted using fresh cornea, preserved in optisol GS
Procedure: Boston KPro type I - fresh graft
Boston KPro mounted on fresh corneal carrier graft for implantation
Experimental: Frozen carrier graft for KPro
KPro implanted using frozen cornea, which was supplied as a whole globe cryopreserved at -80°C in gramicidin 0.025 mg/mL and polymyxin B sulfate 10 000 U/mL ophthalmic solution.
Procedure: Boston KPro type I surgery - frozen graft
Boston KPro mounted on frozen corneal carrier graft for implantation
- Extrusion rate [ Time Frame: 10 years post-KPro implantation ]
- Best-corrected visual acuity [ Time Frame: 10 years ]
- Retroprosthetic membrane formation [ Time Frame: 10 years ]
- Endophthalmitis rate [ Time Frame: 10 years ]
- Sterile vitritis rate [ Time Frame: 10 years ]
- Intraoperative complications [ Time Frame: time of surgery ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01950598
|Centre Hospitalier de l'Université de Montréal|
|Montréal, Quebec, Canada, H2L 4M1|
|Principal Investigator:||Mona Harissi-Dagher, M.D.||CHUM - Hôpital Notre-Dame|