deep lamellar endothelial keratoplasty

Deep lamellar endothelial keratoplasty (DLEK) is a new lamellar keratoplasty developed in recent years. It replaces the lesional posterior corneal layer with a healthy donor posterior lamina and corneal endothelium. Endothelium, therefore also known as posterior lamellar keratoplasty (PLK) or endothelial lamellar keratoplasty (ELK). There are currently two procedures, the lamellar bag method and the pedicled flap procedure. The former has little effect on the anterior corneal 80% matrix and epithelium, so it has small astigmatism, small reaction, avoiding the risk of wound rupture and rapid vision recovery. In the latter case, the slice of the receptor and the donor layer are neat and smooth, and the intraocular operation can be conveniently performed through the opening in the center of the cornea. However, postoperative astigmatism is larger than the former, which is obviously due to suture stitching. Treating diseases: corneal diseases Indication Deep lamellar endothelial keratoplasty is suitable for: 1. Corneal endothelial decompensation caused by various reasons, corneal edema and turbidity. In particular, bullous keratopathy caused by corneal endothelium injury after cataract extraction combined with intraocular lens implantation, Fuchs' corneal endothelial dystrophy. 2. Corneal endothelium is cloudy. 3. The corneal matrix is cloudy. Contraindications With shallow corneal scar formation, endothelial function recovery, edema disappeared, and the cornea could not restore transparency. Surgical procedure Laminate bag method (1) Opening: The suture or the opening device can be used. (2) conjunctival incision: generally cut the ball conjunctiva about 8 ~ 10mm in the upper limbus, separated backwards. Place the rectus muscle fixed traction line to stop bleeding. (3) The posterior border of the limbus is parallel to the limbus incision and is about 9 mm long. The corneal lamellar pocket (about 9 mm in diameter) of 80% thickness is separated and made. In order to accurately grasp the depth of the separation layer, air is injected into the front chamber through a puncture port, and the reflection between the air in the room and the interface of the inner surface of the cornea guides the separation of the layers. (4) A special corneal ring is drilled into the corneal pocket to remove the central posterior corneal stroma and endothelial layer of 7.0-7.5 mm diameter. (5) Donor corneal preparation: The donor cornea cuts the 60% deep anterior layer, retains the deep lamellar layer with the corneal endothelium, and drills the same size of the graft. (6) The deep lamellar graft is placed on a special spoon-shaped skateboard that is covered with a viscoelastic agent and sent to the implant bed. (7) Inject air into the anterior chamber so that the grafts are naturally attached and fixed without suturing. (8) suture the plate layer incision. At present, the procedure can be completed by a self-closing incision of about 5 mm, and the posterior layer can be cut off with scissors, and the incision does not need to be sutured. 2. The combined operation of the pedicled flap method may include: anterior vitrectomy, anterior vitrectomy combined with intraocular lens extraction, extracapsular cataract extraction combined with intraocular lens implantation. (1) Opening: The suture or the opening device can be used. (2) Preparation of superficial corneal flap: the recipient corneal epithelium is removed first. As with the Lasik procedure, an automatic lamellar keratome was used to make a 9.5 mm diameter, 160 m thick (or thickness) pilating pedicle flap upward. (3) The upper rectus muscle fixed traction line. (4) 6.5mm ring drill to drill deep layer. (5) Completion of other intraoperative intraoperative operations, such as intraocular combined surgery, and suture fixation after completion. (6) Preparation of donor graft: The donor corneal surface was first removed with an automatic lamellar keratome. The grafts were drilled from the endothelium using a 7.0 mm trephine. (7) After filling the anterior chamber with viscoelastic agent, place the graft on the planting bed, firstly fix the intermittent suture with key line in the 10-0 nylon line, and then suture it continuously with 8-0 absorbable line. Nylon fixed stitching. (8) BSS liquid rinses out the anterior chamber viscoelastic. (9) pedicle flap replacement and suture. complication 1. Rejection is the same as other corneal transplants, but it is theoretically lighter than full-thickness corneal transplantation. At the same time, most of the surgical cases are simple decompensation of the endothelium, and there are few new blood vessels. It is easy to control the condition through drug treatment. 2. The lamellar bag method occasionally has postoperative graft reversal and corneal endothelium decompensation. Mainly because the intraoperative implants are not fixed. In fact, filling the anterior chamber with air keeps the graft in place, and despite the rapid absorption of the gas, the graft adheres firmly to the recipient cornea. The adhesion of this implant is reliable and independent of the action of the endothelial pump. Therefore, during the operation, the graft is delivered to the implant bed and pressed into place by the gas, and the correct head position can be maintained after the operation to prevent the postoperative implant displacement. 3. Interface scar formation. Sometimes a small amount of scar formation and normal histological healing between the interfaces is shown under the microscope. No need for any processing. 4. Corneal astigmatism. The astigmatism associated with the suture is occasionally used in the lamellar bag method up to 3.5D. However, in the newly reported case of Melles (2000), the average postoperative astigmatism was only 1.54D, and the average postoperative endothelial density was 2520/mm2. All the grafts were in place and transparent 6 to 12 months after surgery, and the best corrected visual acuity was 20/80-2020. Terry et al (2001) evaluated the changes in diopter and astigmatism before and after surgery, and found no significant difference. Even with the pedicled flap, the regular astigmatism of the cornea did not exceed 4D within 4 months after surgery. Compared with penetrating keratoplasty, it shows advantages in controlling postoperative astigmatism. 5. The pedicled flap method generally re-epithelializes the cornea within 4 weeks. However, occasionally, the epithelial endogenous corneal flap is dissolved. In the literature, 1 case of epithelial corneal flap was severely dissolved in 3 months after operation. The corneal flap was removed and the suture was re-surgery.

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