Chapter 58 - Ocular surgery part II Flashcards
What are the risks associated with corneal lacerations?
Vision and globe-threatening complications, infection, and compromised eye structure.
What do you check in ophtalmic exam when there is corneal laceration?
iris involvment
Lens and retina damage
How can iris involvement in a corneal wound complicate repair?
It increases risks like hyphema and endophthalmitis.
How can iris involvement in a corneal wound complicate repair?
It increases risks like hyphema and endophthalmitis.
concurrent trauma to the lens can result in what?
catarat formation and varying degree of uveitis if the lens capsule has been lacerated due to inflammatory reaction
Retinal detachmente due to coup-contrecoup injure can result in loss of globe pressure how is anmed?
(hypotony) occurring with leakage of aqueous humor and globe deflation when the eye is penetrated.
Uncomplicated corneal lacerations may be repaired by primary closure using
simple-interrupted absorbable 8-0 to 9-0 sutures of polyglactin 910 with a spatulated needle.
Why is foreign body depth assessment crucial in corneal injuries?
Removing deep-penetrating foreign bodies can collapse the anterior chamber.
What is the preferred anesthetic setting for surgical repair of corneal lacerations?
Under general anesthesia with magnification.
Describe how the spatulated semi-circular needle is inserted
the spatulated semi-circular needle is rotated in a circular path with no linear pushing, beginning with an entry angle of the needle point close to 90 degrees to the corneal surface. Sutures should be placed symmetrically 1 to 2 mm apart, ensuring the anterior chamber is not entered by the suture.
What is required to maintain an anterior chamber during corneal repair?
Reinflation with balanced salt solution or a viscoelastic agent (sodium hyaluronate 2%).
What is the risk if a suture accidentally enters the anterior chamber?
Possible damage to the iris and lens, and complications from hypotony
What is the recommended tool for manipulating a prolapsed iris?
A blunt spatula or muscle hook. Iris prolapsed should be gently manipulated back into the anterior chamber using blunt spatula or muscle hook while the corneal wound is being closed.
What should be avoided if the iris is incarcerated in the wound?
Excising the prolapsed iris to prevent hyphema and synechia.
How can hemorrhage in the iris be minimized during surgery?
By applying diluted epinephrine (0.1 mg/mL)
and a viscoelastic agent.
What is indicated if corneal tissue is missing and primary closure isn’t possible?
A conjunctival graft or other graft materials like amniotic membrane.
What postoperative therapy is required if the anterior chamber is opened?
Systemic antibiotics and topical anti-inflammatories.
What is the prognosis for uncomplicated corneal lacerations without globe penetration?
Good, with minimal scarring.
Why is prognosis more guarded if there is iris prolapse and large aqueous leakage?
There’s a higher risk of damage to intraocular structures and subsequent complications.
What postoperative complications are possible in corneal laceration repair?
.
Infection, scarring, astigmatism, suture dehiscence, and globe collapse
What tools and techniques are essential for advanced surgical corneal repairs?
General anesthesia, magnification, good illumination, and microsurgical instruments.
What purpose does a conjunctival graft serve in corneal repair?
It provides structural support and vascular supply, promoting healing.
What kind of corneal issues are conjunctival grafts typically used for?
Deep corneal ulcerations, melting ulcers, and corneal lacerations. Where the corneal lesion is deep, or if the dissection inadvertently proceeds to greater than 50% stromal depth, a graft will be indicated.Deep corneal stromal abscessation, corneal malacia, corneal perforations, and iris prolapse.
Why is thin conjunctival dissection important in grafting?
It reduces the risk of graft dehiscence and improves visual and cosmetic outcomes.
How much larger than the defect should a conjunctival graft be?
About 1–2 mm larger to accommodate contraction.
What should be removed if the corneal epithelium has grown around an ulcer before grafting?
The overgrown epithelium to expose the corneal stroma.
Which suture pattern is preferred for attaching a conjunctival graft?
Simple-interrupted suture pattern with polyglactin 910.
How should a defect in the graft created by scissors be addressed?
Close the defect with simple-interrupted sutures.
What are some types of conjunctival grafts?
Advancement grafts, hood grafts, and rotational pedicle grafts.
What additional materials may be needed for deep corneal defects?
Scaffolding materials like amniotic membrane or porcine submucosa.
What medications are typically used postoperatively after conjunctival grafting?
Broad-spectrum topical antibiotics, antifungals, and systemic NSAIDs.
What is the main complication associated with conjunctival grafting?
Graft dehiscence due to inflammation and improper grafting technique.
What strategy helps minimize graft dehiscence?
Minimizing postoperative inflammation and using proper suture depth.
Why is minimizing graft tension important?
It helps prevent graft dehiscence and ensures proper integration.
What issue can arise if collagenase activity continues post-grafting?
Melting of the surrounding cornea, leading to graft failure.
How can graft-induced scarring affect vision?
Large or centrally located grafts may significantly impair vision.
When should the attachment stalk of a conjunctival graft be trimmed?
About 6 weeks postoperatively to reduce scarring.
Why should forceps be avoided when trimming the graft stalk?
To reduce risk of trauma from head movement during trimming
What is the purpose of applying phenylephrine during stalk trimming?
To control hemorrhage.
ow long should postoperative topical antimicrobials be used after grafting?
Typically for about 2 weeks to support healing and prevent infection.
what is a rotational pedicle graft commonly used for?
For treating both centrally and peripherally located corneal defects.
Why is rotational pedicle graft considered versatile?
It suits various corneal defects and offers flexibility in donor site location.
What is essential in planning a rotational pedicle graft?
Ensuring the graft pedicle is of adequate length without excessive tension.
Why is the lateral or dorsal bulbar conjunctiva preferred as a donor site?
It is easier to expose and has less risk of trauma, improving graft success.
How should the patient be positioned during rotational graft surgery?
In lateral recumbency to centralize the corneal position.
Why is graft harvesting typically done before corneal débridement?
To allow rapid closure in case of inadvertent globe penetration.
What is the initial incision location in rotational graft harvesting?
Parallel to and 1-2 mm from the limbus at the flap’s apex.
Why is it important to maintain a thin flap during harvesting?
To prevent excessive tissue and reduce tension on the graft.
What blade is used to prepare the recipient bed?
A 69 Beaver blade.
What type of suture is typically used to secure the graft in place?
Simple-interrupted 8-0 to 9-0 polyglactin 910.
What additional precaution is needed when placing sutures?
Ensure sutures go through the conjunctiva before the corneal lesion edge.
What differentiates an advancement pedicle graft from a rotational graft?
It is used for corneal lesions closer to the limbus.
Why aren’t advancement pedicle grafts ideal for central corneal defects?
Limited flap length creates tension, restricting central defect coverage.
What is the first incision in an advancement pedicle graft?
Parallel to the limbus, slightly longer than the defect’s width.
Why isn’t donor site closure necessary in advancement pedicle grafts?
The advanced conjunctiva naturally covers the site.
What is a hood graft mainly used for?
For lesions adjacent to the limbus.
What is unique about a hood graft’s attachment process?
It can provide temporary coverage and eventually detaches on its own.
How is a hood graft positioned relative to the corneal epithelium?
It may overlay the intact corneal epithelium for temporary protection.
What are bipedicle and bridge grafts used for?
For linear corneal defects or axially located lesions.
How is a bipedicle graft secured?
By suturing the graft tips over the lesion.
What is a potential drawback of a bipedicle graft?
It may offer a less secure attachment than other graft types.
How is a bridge graft different from a bipedicle graft?
It anchors on either corneal side, reducing need for central sutures.
What should be done after a bipedicle or bridge graft?
Close the donor sites with simple-continuous sutures.
What is amniotic membrane transplantation primarily used for?
Promoting corneal wound healing and reducing inflammation.
What layers make up the amniotic membrane?
Epithelial layer, basement membrane, and stromal matrix.
How should a frozen amniotic membrane be prepared?
Thaw and wash in balanced salt solution for 30 minutes.
What are the two main types of amniotic membrane grafts?
Inlay graft and overlay patch.
What is the orientation for an inlay graft of the amnion?
Epithelial/basement membrane side facing upwards.
What role does an overlay patch serve?
Temporary structural support and inflammation reduction.
What is required if the overlay patch does not detach?
Removal from the cornea in about two weeks.
Figure 58-11. 4.0× surgical loupes with light source (Heine).
Figure 58-12. Instruments commonly used for conjunctival surgery, from left to right: Westcott tenotomy scissors, Stevens tenotomy scissors, Bishop-Harmon forceps, Derf needle holder.
Figure 58-13. Guyton-Park eyelid speculum.
Figure
Figure 58-14. Instruments commonly used for corneal surgery, from left to right: Castroviejo needle holder, Colibri corneal forceps, Martinez corneal dissector, Castroviejo corneal section scissors, Castroviejo universal corneal scissors, straight suture-tying forceps, curved suture-tying forceps.
Figure 58-15. Beaver scalpel blades and Beaver handle, from left to right: No. 69 blade, No. 65 blade, No. 64 blade, blade handle.
Figure 58-16. (A) Correct placement of sutures to a depth of 80% of the cornea. (B) Close-up view.
Figure 58-19. Cellulose ocular stick (top), and Weck-Cel cellulose sponge spear (bottom).
Figure 58-20. Protective eye-cup mask to prevent damage to the surgical site.
Figure 58-21. Intraoperative image of a superficial keratectomy performed with a 69 Beaver blade and Martinez corneal dissector.
Figure 58-22. Ophthalmic cryoprobe tips (Cooper-surgical N2O cryotherapy unit) suitable for direct ocular surface application for adjunctive therapy of ocular surface neoplasia.
Figure 58-26. Hood conjunctival graft. (A) An incision is made 1 mm from the limbus, and the bulbar conjunctiva is undermined toward the fornix. (B) Both ends of the graft are sutured to the adjacent limbus. (C) The hood is advanced and sutured to the cornea.
Figure 58-27. Bridge conjunctival graft. (A) Bulbar conjunctival incisions parallel to the limbus, undermined and isolated from underlying Tenon’s capsule. (B) The bridge of conjunctiva is sutured to the cornea along two sides of the corneal ulcer.
Figure 58-28. Sliding lamellar keratoplasty. (A) Diverging corneal incisions extending from the lesion into the conjunctiva, a Martinez corneal dissector is used to elevate the flap of cornea, and tenotomy scissors are used to undermine the bulbar conjunctiva. (B) The graft is advanced over the defect and sutured along the edges of the incisions.
Figure 58-30. Posterior lamellar keratoplasty. A three-sided incision is created with a 69 Beaver blade and undermined with a Martinez corneal dissector. A punch biopsy is used to delineate the circular deep stromal lesion. The lesion is removed and a button of donor tissue is sutured into the resulting defect. The anterior flap is subsequently sutured closed.
Figure 58-31. Deep lamellar endothelial keratoplasty. A limbal-based incision is undermined with a Martinez corneal dissector and elevated. A punch biopsy delineates the circular deep stromal lesion. The button of donor tissue is placed into the resulting defect without suturing. The anterior flap is sutured closed at the limbus.
