Imaging Ahmed Glaucoma Tubes With a Pericardial Graft and Tissue Glue or Partial-Thickness Scleral Flap and Sutures

May 12, 2008 updated by: National University Hospital, Singapore

Anterior Segment Optical Coherence Tomography Findings in Patients With Ahmed Glaucoma Drainage Implants With Either a Pericardial Patch Graft and Fibrin Tissue Glue or a Partial-Thickness Scleral Flap and Conventional Sutures

When implanting an Ahmed glaucoma tube, a scleral flap is usually created to cover the tube, and the conjunctiva is stitched back in place with nylon 10-0 sutures. It is hypothesized that an equally safe or better method is using a bovine pericardial patch graft that can be secured in place over the tube with tissue glue, and using tissue glue to reposition the conjunctiva in place.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Unknown

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Glaucoma drainage devices (GDD) are usually reserved for cases wherein filtration surgery has failed, or for difficult cases that do not respond to filtration surgery, such as neovascular or uveitic glaucoma.

The Ahmed Glaucoma drainage implant (New World Medical, Rancho, Cucamonga,CA) was introduced to the market in 19942. It has a scarab-shaped end plate made of polypropylene (models S2, S3 and B1) or silicone models (FP7, FP8 and FX1). Fenestrations have been added to the end plate of the silicone models. Various sizes of the Ahmed drainage are available, including those with a surface area of 96 mm2 (S3 and FP8) or 184 mm2 (S2 and FP7); while the double-plate version has a surface area of 364mm2 (B1 and FX1). Aqueous humor passes from the anterior chamber through two thin membrane-like elastomer sheets that theoretically restrict flow until a pressure of greater than 8-12 mm Hg is exerted on them.

In the implantation of GDD, absorbable and non-absorbable sutures are used. Sutures are typically used in securing the plate to the sclera, securing the tube to the sclera, suturing a patch graft or scleral flap over the silicone tube, and for conjunctival closure. Post-surgical course can be marked by discomfort, depending on the type of suture used. Absorbable sutures can induce inflammation with localized surface and subconjunctival fibrosis that leads to uneven conjunctival surface and excessive scarring. On the other hand, non-absorbable sutures can erode through tissue post-operatively. Suturing the conjunctiva can cause button-holes and tears, and can be the most time-intensive portion of the surgery.

Fibrin glue has been used in various ophthalmic surgeries such as a sealant for perforated and preperforated corneal ulcers, in mucous membrane grafts, in the management of complicated hypotony and bleb leaks after trabeculectomy, and for preventing immediate postoperative hypotony after glaucoma drainage implant surgery.

In a paper by Kahook and Noecker published in 2006, the authors did a retrospective non-randomized case-control study that reviewed 28 cases of GDD implantations using traditional suture materials compared to 14 consecutive cases of GDD implantation using Tisseel fibrin glue (Baxter AG, Vienna, Austria) for closing the conjunctiva, securing the pericardium patch graft and securing the tube to the sclera. The authors concluded that Tisseel fibrin glue seems to be a safe substitute for some of the sutures used in GDD surgery; and it has no impact on IOP control or complications. It appears to reduce post-operative conjunctival inflammation and time of surgery.

Optical coherence tomography (OCT) is a high-resolution, non-invasive and reproducible imaging technology that was primarily developed to evaluate the retina and retina nerve fiber layer in patients with vitreo-retinal or optic nerve diseases11. Recently, the anterior segment OCT (AS-OCT) has been developed and used to image anterior segment structures. It has also been used to localize the Ex-PRESS miniature glaucoma implant in porcine eyes, while the conventional OCT was used to show the anterior segment findings after non-penetrating deep sclerectomy and the filtering blebs of eyes that underwent glaucoma filtering surgery.

Patients scheduled for Ahmed Tube surgery, with or without lens extraction and intraocular lens implant, will be recruited and randomized into two groups. The first group of patients will have a pericardial patch graft covering the tube, and fibrin glue will be used to attach the graft to the sclera and to close the conjunctiva. The second group will have a partial- thickness scleral flap raised to cover the tube, and the conjunctiva will be closed with conventional sutures.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

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Study Locations

  • Singapore
      • Singapore, Singapore, 119074
        • Recruiting
        • National University Hospital
        • Sub-Investigator:
          • Grace Dizon, MD
        • Sub-Investigator:
          • Jovina See, MMed,FRCS
        • Sub-Investigator:
          • Cecilia Aquino, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

41 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • More than 40 years old
  • Able to give informed consent
  • Diagnosis of any type of glaucoma needing a Glaucoma drainage device (Ahmed tube implant) with or without lens extraction and intraocular lens implant because of uncontrolled intraocular pressures inspite of maximum tolerated medical therapy

Exclusion Criteria:

  • Inability to give informed consent
  • History of ocular infection or inflammation in the past two months

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Intraocular pressure
Anterior segment optical coherence tomography appearance and measurements of the overlying conjunctiva, areas above and beneath the pericardial patch graft or partial thickness scleral flap, anterior chamber depth

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National University Hospital, Singapore

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Paul Chew, FRCSEd,MMed, National University Hospital, Singapore

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2007

Study Completion (Anticipated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 1, 2008

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 27, 2007

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 27, 2007

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 28, 2007

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 14, 2008

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 12, 2008

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2008

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DSRB A/06/375

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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