Aqueous Drainage Device Implantation

Water drainage device implantation is an extraocular filtration procedure. It drains aqueous humor from the anterior chamber to the outside of the eye through a aqueous drainage device. There are three main types of aqueous drainage devices: 1. The aqueous humor is drained from the anterior chamber to the anterior subconjunctiva. Since the fibrous tissue under the conjunctiva envelops the outer mouth of the aqueous drainage device, the surgery is prone to failure. 2 The aqueous humor is drained from the anterior chamber to the suprachoroidal space through the cleft of the ciliary body. Due to the difficulty of surgical operation, anterior chamber bleeding is prone to occur and has rarely been applied. 3 The aqueous humor is drained from the anterior chamber through the limbus to the aqueous humor collection device fixed to the equator of the eyeball. After nearly 30 years of clinical application and improvement, the curative effect has been continuously improved and the complications have been gradually reduced, which has been widely used. This article describes the implantation of this type of aqueous drainage device. Treatment of diseases: neovascular glaucoma congenital glaucoma Indication Mainly for refractory glaucoma, such as neovascular glaucoma and primary glaucoma surgery after scleral cerclage, surgical treatment of failed congenital glaucoma, adolescent glaucoma, traumatic glaucoma, aphakic and intraocular lens glaucoma Glaucoma after corneal transplantation, glaucoma secondary to uveitis, and other types of glaucoma. Contraindications The aqueous humor is drained from the anterior chamber to the anterior subconjunctiva. Since the fibrous tissue under the conjunctiva envelops the outer mouth of the aqueous drainage device, the surgery is prone to failure. Preoperative preparation Commonly used aqueous drainage devices are as follows: 1. The molteno aqueous water drainage device consists of a silicone tube with an outer diameter of 0.63 mm and an inner diameter of 0.33 mm and a polypropylene disk with a diameter of 13 mm. There is no valve in the silicone tube. The disc has a curved surface that is adapted to the shape of the outer surface of the sclera. The edge of the disc has a hard edge and a thickness of 0.7 mm. There are two types of single disc and double disc, which are selected according to the level of intraocular pressure that needs to be controlled. 2. The ahmed glaucoma aqueous drainage valve consists of a silastic tube bonded to an elliptical polypropylene plate. The front surface area of the polypropylene sheet was 184 mm 2 (13 mm × 16 mm). The valve consists of two pressure-sensitive, oppositely placed silastic membranes. When the intraocular pressure is 8 ~ 12mmhg, the valve is open, allowing the outflow of aqueous humor. 3. The baerveldt aqueous water drainage device is composed of a silicone tube having an inner diameter of 0.3 mm and a thin plate of a polymer material containing ruthenium having a thickness of 1 mm. The surface area of the sheet has three types of 200 mm 2 (20 mm × 13), 350 mm 2 (32 mm × 14 mm), and 500 mm 2 (36 mm × 17.5 mm). 4. The krupin aqueous water drainage valve disk is composed of a silastic tube with an inner diameter of 0.38 mm and a thin plate of 1.75 mm thick and 13 mm×18 mm. The tube is fitted with a one-way pressure sensitive slit valve. When the intraocular pressure is higher than 11mmhg, the valve is open, and when the intraocular pressure is lower than 9mmhg, the valve is closed. Surgical procedure The method of implanting various aqueous drainage devices is roughly the same. The following is a description of the molteno single-disc aqueous drainage device. 1. The surgical site of the conjunctival flap is generally selected in the upper quadrant, or in the nasal upper quadrant. After the device is opened, the bulbar conjunctiva and the fascia of the sclera are cut in the upper quadrant of the iliac crest, and the conjunctival flap is the base of the iliac crest, and is placed at both ends of the incision (at 12 o'clock and 3 o'clock or 9 o'clock) The Qianlong Department made a loosening cut. Make a blunt dissection to the Qianlong, fully burn and stop bleeding. 2. The superior rectus and lateral rectus muscles were separated by a squint hook, and the 4-0 silk thread was passed through the tendon as a traction line. Pull the pull line down to fully expose the surgical site. 3. The fixed room water mourning device places the plate end of the aqueous water drainage device on the sclera surface above the iliac crest. The front end is 9 to 10 mm from the limbus. A 5-0 non-absorbent suture is used to suture the two needle fixation lines in the scleral plate layer, and through the small hole in front of the plate end of the aqueous drainage device, the ligature is fixed. 4. Trim the silicon tube of the aqueous water drainage device so that the front end of the silicon tube is inclined, and the length can be 2~3mm long in the anterior chamber after insertion into the anterior chamber. 5. Perform a corneal puncture in the nasal or temporal sclerotomy to inject balanced saline into the anterior chamber during surgery. 6. Puncture the upper corneal limbus with a needle with a tube diameter similar to the outer diameter of the silicone tube. The needle is inserted about 2 mm from the corneoscleral margin, passes through the scleral lamina to the corneoscleral margin, and then penetrates into the anterior chamber. The needle should remain parallel to the iris plane. 7. Insert the trimmed silicone tube into the anterior chamber via the limbal needle, and fix the silicone tube to the superficial sclera with a 9-0 or 10-0 nylon thread. 8. A 5 mm x 6 mm allogeneic scleral lens was placed on the silicone tube, the front end of which was aligned with the corneal limbus, and a needle was fixed at each of its four corners with a 10-0 nylon thread. 9. Suture the bulbar conjunctiva and the fascia wound with a 10-0 nylon thread. complication The limbus drains aqueous humor from the anterior chamber to the aqueous humor collection device that is attached to the equator of the eyeball. The curative effect is continuously improved and the complications are gradually reduced, which has been widely used.