Glaucoma Trabeculectomy Surgery Video
Trabeculectomy, also called Filtration Surgery, is a surgical procedure performed for treatment of glaucoma. The treatment involves removing part of the trabecular meshwork and creating a new escape route for the aqueous humor. When successful, it allows the aqueous fluid to drain from the eye into an area underneath the conjunctiva where it is subsequently absorbed by the body’s circulatory system or filtered into tears.
In this procedure:
– A conjunctival pocket is created and maybe treated with Mitomycin or other antimetabolites for a few minutes. These drugs are used to prevent scarring of the operation site. Scarring, if occurs, may clog the new drainage canal, and is therefore the major reason the procedure may fail.
– A half thickness flap is then made in the sclera and is dissected all the way to the clear cornea.
– A block of scleral tissue including part of the trabecular meshwork and Schlemm’s canal is then removed to make a hole into the anterior chamber of the eye.
– As the iris may plug up this hole from the inside, a piece of the iris maybe removed at this time. This is called iridectomy.
– The scleral flap is then sutured loosely back in place. These sutures can be released gradually during a couple of weeks after surgery. This allows adjustment of the aqueous flow in order to achieve target pressure and to avoid the complication of having a too low intraocular pressure.
– The conjunctiva is sewn back in place to cover the area.
After surgery, aqueous humor drains into a filtering area called a “bleb” under the conjunctiva. Since the surgery is usually performed near the top of the eye, the bleb can easily be concealed behind the upper eyelid.
Another Video illustrates my technique that I have been following for the last 25 years, thanks to the teaching of Dr R J Simmons MD, of Harvard University, & the New England Glaucoma Foundation.
This is a case of congenital glaucoma that failed previous treatments and surgeries. In this video, Dr. Kwon demonstrates a combined surgical approach using Mitomycin C trabeculectomy with trabeculotomy.
Mitomycin C Trabeculectomy & Trabeculotomy in Glaucoma
Professor Anthony Molteno developed the first glaucoma drainage implant, in Cape Town in 1966. Following on the success of the Molteno implant, several varieties of device have been developed from the original, the Baerveldt tube shunt, or the valved implants, such as the Ahmed glaucoma valve implant and the later generation pressure ridgeMolteno implants. These are indicated for glaucoma patients not responding to maximal medical therapy, with previous failed guarded filtering surgery (trabeculectomy). The flow tube is inserted into the anterior chamber of the eye and the plate is implanted underneath the conjunctiva to allow flow of aqueous fluid out of the eye into a chamber called ableb.
The ExPress Mini Shunt is a newer, non-valved device that was originally designed to provide a direct conduit from the anterior chamber to the sub-conjunctival space or bleb. In this position it was unstable and tended to erode through the conjunctiva. Now the more common use is as a modification of the trabeculectomy procedure, placed under a scleral flap, replacing the sclerostomy step
Ahmed Valve Surgery
The Ex-Press Mini Glaucoma Shunt has been available internationally for almost a decade with almost 35,000 implantations world wide. The device shunts aqueous from the anterior chamber to a subconjunctival reservoir in a similar fashion as trabeculectomy, without removal of any sclera or iris tissue. Developments in ophthalmic surgery have been focused on smaller incisions to improve patient outcomes and visual recovery. The Ex-Press is an example of these developments. This article will review the surgical technique for implanting the Ex-Press Mini Glaucoma Shunt and will highlight the clinical experience with the device.
Phaco Trabeculectomy – combined surgery