Trabeculectomy

Drug and laser treatments do not prevent glaucoma of various types of progressive optic nerve damage and visual field defects. Due to improvements in surgical techniques and the use of antimetabolites, intraocular pressure levels after trabeculectomy can be similar to those of full-thickness scleral penetrating filtration, so trabeculectomy is now available for almost all needs. Glaucoma for extraocular filtration. Treatment of diseases: trauma-related glaucoma primary open angle glaucoma glaucoma chronic angle-closure glaucoma Indication Drug and laser treatments do not prevent glaucoma of various types of progressive optic nerve damage and visual field defects. Preoperative preparation Patients should be informed enough about their condition and prognosis. Adjust the preoperative medication. Proine or 1% adrenaline, anti-cholinesterase inhibitors such as iodine phosphate, superior gaze, etc. should be discontinued for two weeks in order to reduce vascular congestion and intraoperative bleeding. The carbonic anhydrase inhibitor and the -adrenergic blocker were stopped for 2 to 3 days, so that the formation of aqueous humor was normal after the operation, which was conducive to the formation of filtration bleb. Antibiotic eye drops such as 0.3% tobramycin were added 3 days before surgery. Gentamicin eye drops may stimulate the bulbar conjunctiva, causing conjunctival hyperemia and avoiding it as much as possible. 1% prednisolone can be started on the day before surgery, 4 times a day. If the patient has not used pilocarpine, use it 1 or 2 times a day before surgery. If the preoperative intraocular pressure is significantly elevated (above 40mmHg), 20% mannitol should be administered intravenously to reduce intraoperative complications. If the patient takes aspirin, it should be discontinued for 5 days. If there are new blood vessels in the iris or anterior chamber angle, panretinal photocoagulation should be performed first to increase the success rate of filtration. Surgical procedure 1. Angle of the limbal corneal puncture: generally located under the ankle, the size should be sufficient to allow the fine irrigation needle to penetrate into the anterior chamber. Intraocular filtration during corneal puncture provides intraoperative anterior chamber water injection, irrigation, examination of the degree of scleral flap water permeability, and the passage to restore the anterior chamber at the end of surgery. 2. Sew the rectus muscle traction line. 3. Do the bulbar conjunctival flap: the position of the bulbar conjunctiva is generally selected above. It can also be selected in other quadrants or even below, as needed. The conjunctival flap has two types, the limbus as the base and the dome. For young patients with thick conjunctiva, it is hoped that postoperative intraocular pressure will be controlled to remove the fascia. (1) The conjunctival flap with the limbus as the base: the assistant grasps the bulbar conjunctiva with the toothless flat jaw and pulls it toward the pupil side. A full-thickness incision is made by clamping the bulbar conjunctiva and the fascia with a gum. The incision is 8 to 10 mm from the limbus. It is separated forward along the scleral plane under direct vision until the limbus. (2) The conjunctival flap of the iliac crest is the base: the upper or other quadrant of the limbus cuts the bulbar conjunctiva and the fascia for about 3 hours. Backward separation, appropriate exposure of the area where the scleral flap is prepared. 4. Doing the scleral flap: The shape of the scleral flap has no relationship with the postoperative intraocular pressure control level. Quadrilateral, triangular, etc. can be used. Use a cautery to burn and stop the incision at the incision for the scleral flap, but the burning should not be excessive. Use a sharp knife to make the scleral flap based on the limbus. Make two incisions perpendicular to the limbus, the front end to the clear cornea, but not the conjunctival flap. Then make a slit parallel to the limbus and connect the three sides to make a 4 mm × 3 mm quadrilateral. The depth of the incision is approximately 1/2 or 1/3 of the scleral thickness. Hold the edge of the scleral flap with tweezers, flip it as far as possible, and gently pull it toward the pupil side. Use a sharp knife to gently cut the fibers between the sclera layers in a direction that almost flattens the sclera. Separate forward until clear 1 mm in the corneal area. 5. Excision of deep sclera tissue: The anterior chamber angle partially determines the location of deep scleral tissue resection. In the narrow angle of the anterior chamber, especially in the peripheral part of the anterior iris, the deeper part of the sclera should be removed more than usual to avoid injury to the iris root and ciliary body. The assistant clamped the edge of the scleral flap with tweezers and gently pulled it toward the pupil side. The surgeon used a sharp knife tip to make two parallel scleral incisions with a spacing of about 1.5 to 2 mm from the anterior border of the limbus to the posterior border. An incision parallel to the limbus is then made at the anterior border of the limbus between the two incisions. The free edge of the corneoscleral tissue was clamped with forceps and turned backwards, and then the deep tissue of the cornea was cut with scissors by 1.5 mm × 1 mm or 2 mm × 1.5 mm. Partial corneal sclera deep tissue can also be removed by bite cutting. 6. Peripheral iridotomy: Use the forceps to clamp the exposed iris tissue in the corneoscleral incision, gently lift it and turn it slightly back. The iris scissors were made parallel to the corneoscleral limb for peripheral iridotomy. Rinse the corneal scleral resection and gently massage the cornea from the corneoscleral resection to the pupil with the iris restorer to restore the iris. 7. Stitching the scleral flap: the scleral flap is repositioned. Knotted with the 10-0 nylon thread intermittently sutured at the two free angles. Then, the balanced saline was injected into the anterior chamber through the corneal puncture, and the liquid extravasation on the side of the scleral flap was observed. If there is too much extravasation, the scleral flap should be added. If the extravasation is too small, it indicates that the scleral flap is too tight and should be adjusted. 8. Stitching the conjunctival wound: If the conjunctival flap is the base of the limbus, the wound is sutured with a 10-0 nylon thread intermittently or continuously. If the conjunctival flap is based on the iliac crest, a needle is sutured at the ends of the conjunctival incision. In order to prevent the leakage of the wound in the early postoperative period, the edge of the conjunctival incision can be sutured parallel to the corneal limbus, so that the edge of the conjunctival wound is in close contact with the cornea of the peripheral part. 9. Restoration of the anterior chamber: After suturing the conjunctival wound, inject the balanced saline into the anterior chamber through the corneal puncture to restore the anterior chamber and understand the leakage of the conjunctival wound. If leakage is found, suture should be added.