Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04931290 |
| Other study ID # |
R.21.03.1246.R1.R2 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
April 6, 2021 |
| Est. completion date |
February 1, 2022 |
Study information
| Verified date |
September 2022 |
| Source |
Mansoura University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
This study aims to assess the safety and efficacy of supracapsular Ahmed Glaucoma Valve plate
delivery for management of encapsulated bleb in pediatric patients with failed Ahmed Glaucoma
Valve.
This is a prospective interventional study. It will be conducted in Mansoura University in
the duration from April 2020 to January 2021. The study will include pediatric patients less
than 18 years with failed AGV with encapsulated bleb and high IOP above 21 mm Hg in two
consecutive visits inspite of topical glaucoma medications
Description:
Introduction Refractory glaucoma is a complicated type of glaucoma that is characterized by
high intraocular pressure (IOP), making it difficult to treat by traditional medical or
surgical therapies. Trabeculectomy has shown poor long-term outcomes for refractory glaucoma,
making shunt surgery a better alternative. [1]Ahmed glaucoma valve (AGV) is effective
procedure in management of refractory glaucoma with long-term follow-up in Egyptian
patients.[2] AGV, a shunt device, is used either initially or after conventional procedures
fail to treat refractory glaucoma. It helps the aqueous humor flow directly into the silicone
tube.[3] Encapsulation of the AGV is an early complication especially in pediatric patients
leading to postoperative elevation of intraocular pressure [4]. Encapsulation inhibits the
fluid drainage leading to failure of the procedure. The valve mechanism is blocked by
contracted scar tissue, but the device itself is not affected by the encapsulation..[5] The
reasons for this excessive fibrotic reaction and capsule impermeability are not fully
understood. Apart from implant properties, such as size, shape, surface properties and
biomaterial other mechanisms leading to collagen distribution, proliferation and adhesion of
fibroblasts have been suggested to contribute to the encapsulation process .[6]
Different techniques were developed for revision of this encapsulated bleb. Surgical excision
of the capsule immediately leads to an aqueous flow and drop of intraocular pressure [4, 7],
but it carries the risk of reformation of the capsule again. Bleb needle revision is another
method that targets the fibrosis tissue and has long been employed in the treatment of
encapsulated bleb following trabeculectomy. Despite the favorable outcomes after
trabeculectomy, this modality is not generally used after AGV implantation. A few reports
have investigated the application of needle revision in AGVs[8] Using antimetabolites as
mitomycin c and 5-FU during needling over the plate of an AGV may also be an effective and
safe choice in patients with elevated IOP due to encapsulation or fibrosis.[9] Aim of the
Study This study aims to assess the safety and efficacy of supracapsular Ahmed Glaucoma Valve
plate delivery for management of encapsulated bleb in pediatric patients with failed Ahmed
Glaucoma Valve.
Patient and methods This is a prospective interventional study. It will be conducted in
Mansoura University in the duration from April 2020 to January 2021. The study will include
pediatric patients less than 18 years with failed AGV with encapsulated bleb and high IOP
above 21 mm Hg in two consecutive visits inspite of topical glaucoma medications. Patients
with intraocular inflammations or ocular surface diseases will be excluded from the study.
The outcome will be measured as IOP and its association with the number of postoperative
glaucoma medications. IOP ≤ 21 mmHg without medications indicates complete success while IOP
≤ 21 mmHg with medications indicates qualified success, an IOP <6 mmHg i defined as hypotony
and IOP above 21 mm Hg with medications indicates failure Cooperative patients will
preoperatively be subjected to IOP measurement using hand held Perkin's applanation
tonometer, visual acuity (VA) assessment using a Snellen E chart, optic disc examination by a
Volk+90 lens, slit lamp examination for assessment of corneal clarity, and assessment for any
corneal tube-touch and measurement of anterior chamber depth. Examination under anesthesia
will be done in younger or uncooperative children.
The following operative technique will be followed: incision of the perilimbal superior
temporal conjunctiva with separation of the conjunctiva from the Tenon's capsule till
reaching the encapsulated valve plate. Incision of the capsule in a z pattern will be done
then the plate is dissected from the tissues and delivered out of the capsule through the
opening to the subconjunctival space.The mobility of AGV and its tube will be evaluated and
refixation of the plate will be done if needed. The plate will be covered with ologen implant
sizing 12mm width and 1 mm thickness. The conjunctiva will be closed by 10/0 nylon sutures.
A postoperative treatment course of combined antibiotic and steroid eye drops every four
hours in the first week, gradually tapered over the next 2 weeks, will be prescribed. IOP,
VA, and optic disc examination by Volk+90 lens, and slit lamp examination will be performed
at the follow-up period at 1st day, 1st week , 1st month and 3rd month postoperatively.
Ethical Consideration:
Study protocol is approved by medical research ethics committee, faculty of medicine,
Mansoura University.Informed written consent will be obtained from each patient's parents
after being informed of the risks, benefits, and alternatives of surgery. The confidentiality
of participant data is ensured. The participants are free not to participate or to leave the
research at any time, without penalty Statistical analysis Statistical analyses will be
carried out using the Statistical Package for Social Sciences (SPSS 19.0 for windows, SPSS
Inc, Chicago, IL, USA). Results will be considered statistically significant when P is <
0.05.
