Surgery and Complications



Surgery and Complications





CATARACT EXTRACTION AND INTRAOCULAR LENS IMPLANTATION

Cataract extraction and intraocular lens (IOL) implantation involve removal of a cloudy crystalline lens and replacement with an artificial lens. It is one of the most commonly performed surgical procedures.



Surgical Technique

• Anesthesia: topical or local

• Extracapsular method: An incision is made near the limbus, an anterior capsulotomy is performed, the lens nucleus is prolapsed out of the eye, the residual cortical material is removed, an IOL is placed, and the wound is usually sutured.

• Phacoemulsification method: A small limbal or clear corneal incision is made, an anterior capsulotomy is performed, the lens nucleus is fragmented and removed with an ultrasound probe, the residual cortical material is removed, and an IOL is placed. Often, no sutures are required. More recently, femtosecond laser technology has been used to perform certain aspects of cataract surgery, such as creating the anterior capsulotomy and softening the lens making removal less traumatic to the eye, and performing astigmatic keratotomy (AK) incisions with potential benefits over standard phacoemulsification surgery.

• Postoperative management: topical corticosteroid and antibiotics, often a nonsteroidal anti-inflammatory drug (NSAID)



Success Rate

• Excellent. PCO may require a laser capsulotomy.







FIGURE 10-1. (continued) C. This posterior chamber IOLs has subluxed inferiorly. An oblique rent in the posterior capsule can be seen, compromising capsular support. An inferior subluxation is often termed a “sunset syndrome.” Pupillary capture. D. This posterior chamber IOL is partially captured by the iris in this eye 2 weeks after cataract surgery. It was repositioned into the posterior chamber in the operating room.







FIGURE 10-1. (continued) Posterior capsular opacity (PCO). E. A moderate PCO is evident in this eye several years after cataract surgery. Fibrosis of the initially clear posterior capsule often occurs after cataract surgery and can affect visual clarity. Note the arc of opacified anterior capsular rim inferiorly and the fibrotic posterior capsule centrally. When this affects visual function, treatment is with a laser capsulotomy. F. Using retroillumination of the retina, significant posterior capsule opacity is readily appreciated in this eye after combined penetrating keratoplasty and cataract surgery.



FULL-THICKNESS CORNEAL TRANSPLANTATION (PENETRATING KERATOPLASTY)

Penetrating keratoplasty (PK) involves removal of diseased host tissue and replacing it with full-thickness normal donor cornea. It is one of the most successful transplant operations today, depending on the primary corneal disease.



Donor Tissue Contraindications

• Death from unknown cause

• Death from central nervous system diseases of unknown etiology

• Central nervous system infections (e.g., Creutzfeldt-Jakob disease, subacute sclerosing panencephalitis, progressive multifocal leukoencephalopathy)

• Systemic infections (e.g., AIDS, viral hepatitis, rabies, septicemia, cytomegalovirus infection)

• Reye syndrome

• Lymphoma and leukemia


Unfavorable Prognostic Factors

• Severe stromal vascularization

• Previous graft rejection

• Decreased corneal sensation (e.g., herpes keratitis)

• Pediatric patients

• Active uveitis

• Significant anterior synechiae

• Uncontrolled glaucoma

• Active corneal or intraocular infection

• Severe dry eyes

• Ocular surface inflammation, cicatrization, and keratinization

• Significant limbal stem cell deficiency

• Extreme thinning or irregularity at the intended graft-host junction

• Eyelid disorders: ectropion, entropion, exposure


Surgical Technique

• Anesthesia: local or general anesthesia

• Preparation of operative eye: Often, placement of a Flieringa ring helps to stabilize the globe.

• Determination of graft size: Routine graft sizes vary from 7.25 to 8.5 mm.

• Trephination of donor cornea: typically performed using a posterior endothelial punch method, but can also be performed with a femtosecond laser. The trephine is usually 0.25 to 0.5 mm larger than that for host cornea trephination.

• Excision of host cornea: Trephination of host cornea can be done by using a manual trephine (e.g., Weck trephine), a vacuum trephine (e.g., Barron-Hessburg or Hanna trephine), or a femtosecond laser. A partial-thickness trephination is first carried out, the anterior chamber is then entered using a blade, and finally excision is completed using corneal scissors.


• Wound closure: Various suture methods, including interrupted, running, double running, or a combination, may be used. 10-0 nylon is usually used (Fig. 10-2A-C).

• Postoperative management: topical corticosteroids and antibiotics


Combined Procedures

• Where indicated, PK can be combined with any of the following procedures:

▪ Cataract extraction with IOL implantation (PK triple procedure)

▪ Anterior vitrectomy with IOL implantation

▪ IOL exchange, either anterior chamber lens or scleral or iris fixated posterior chamber lens

▪ Glaucoma drainage devices or trabeculectomy

▪ Pars plana vitrectomy, often with a temporary keratoprosthesis



Success Rate

• Poor to excellent, depending on the indication for surgery







FIGURE 10-2. Corneal transplant. A. A clear corneal transplant is seen 6 weeks after surgery for herpes simplex scarring. Sixteen interrupted 10-0 nylon sutures are in place. B. A clear corneal transplant is seen 4 months after a corneal transplant for worsening Fuchs dystrophy with scarring after cataract surgery. Also, 12 interrupted and 12 bite running 10-0 nylon sutures are present. C. An old square corneal transplant performed by Dr. Castroviejo in New York City about 40 years earlier. The graft remains remarkably clear, although a cataract is developing.







FIGURE 10-2. (continued) Corneal transplant complication—early endophthalmitis. D. Ten days after a corneal transplant, severe intraocular inflammation with fibrin in the anterior chamber and a small hypopyon at the graft-host margin inferiorly can be seen. Endophthalmitis was suspected, and a vitreous tap revealed Staphylococcus epidermidis, which responded well to antibiotic treatment. Corneal transplant complication—primary graft failure. E. Diffuse severe corneal edema with whitening of the corneal stroma is present 1 day after a corneal transplant in an eye with primary graft failure. Primary graft failure generally occurs as a result of poor-quality tissue or damage to the corneal endothelium during surgery. Corneal transplant complication—wound leak. F. A wound leak is seen 3 days after a corneal transplant. Dark, concentrated fluorescein dye was placed at the graft-host margin at the 9 o’clock position. Aqueous fluid leaking through the graft-host wound can be seen to dilute the dye and turn it bright yellow-green. If the leak is minimal and the anterior chamber is formed, it can be treated medically and followed closely. If the leak is significant or the chamber is flat, the leak should be repaired surgically.







FIGURE 10-2. (continued) Corneal transplant complication—wound melt. G. A severe corneal wound melt is present in the inferior half of this cornea 5 months after a corneal transplant. Multiple loose sutures can be seen. A small, permanent lateral tarsorrhaphy had already been performed. Corneal transplant complication—suture abscess. H. A broken corneal transplant suture and underlying abscess are present at the 10 o’clock position. A large hypopyon with a second small hypopyon at the graft-host junction can be seen inferiorly. Corneal transplant complication—epithelial downgrowth. I. A curvilinear retrocorneal membrane can be seen from 9 o’clock toward 12 o’clock and back down toward 3 o’clock. It is again visible around 5 o’clock. It advanced centrally over several weeks. It was diagnosed as epithelial downgrowth.







FIGURE 10-2. (continued) Corneal transplant complication—broken interrupted suture. J. A broken corneal transplant suture is present at the 2 o’clock position. Fluorescein dye and cobalt blue light demonstrate the “windshield wiper” effect of the broken suture. Corneal transplant complication—loose, exposed running suture. K. An extremely loose and exposed running suture can be seen a year after corneal transplant. There is mucus adherent to the suture and secondary peripheral corneal neovascularization superiorly and corneal edema centrally. Expulsive hemorrhage after a corneal transplant wound dehiscence. L. Several years after a penetrating keratoplasty, blunt trauma caused the wound to dehisce that resulted in an expulsive hemorrhage. Note the large clot of blood exiting the wound. Iris pigment and vitreous jelly can be seen on the inferior cornea.



ENDOTHELIAL KERATOPLASTY

Endothelial keratoplasty (EK) involves removal of diseased Descemet membrane and endothelium (most commonly) and replacement with healthy Descemet and endothelium alone (Descemet membrane endothelial keratoplasty [DMEK]), or with some posterior stroma (Descemet stripping endothelial keratoplasty [DSEK]).


Advantages over a PK

• More rapid visual recovery (Fig. 10-3A-E)

• Stronger wound

• No corneal sutures

• Less change in corneal curvature

• Not an open-sky procedure

• Lower risk of rejection


Disadvantages Compared to a PK

• Technically more challenging; more difficult to perform other intraocular surgeries

• Potentially more traumatic to the donor endothelium

• Possibly higher risk of postoperative infection in the lamellar interface


Most Common Indications

• Fuchs dystrophy

• Pseudophakic bullous keratopathy


Surgical Technique

• Anesthesia: topical, local, or general anesthesia

• Determination of graft size: Routine graft sizes vary from 7.5 to 8.5 mm.

• Preparation of donor cornea: DSEK graft is typically fashioned with a microkeratome but can be fashioned with a femtosecond laser using an artificial anterior chamber or manually using a whole globe. DMEK tissue is generated manually.

• Removal of host Descemet and endothelium: Through a small scleral, limbal, or clear corneal incision, Descemet membrane is scored, stripped, and removed from the eye.

• Insertion of the donor cornea: Numerous insertion methods, including folding and using a variety of inserters, are used to place the donor cornea in the eye. An air bubble is used to push and hold the donor cornea up against the posterior stroma. A nonexpansile gas (e.g., 18% sulfur hexafluoride) may be used for DMEK. The wound may be sutured closed; 10-0 nylon is usually used.

• Postoperative management: topical corticosteroid and antibiotics. Patients are instructed to lay supine as much as possible for 1 to 5 days, less for DSEK, more for DMEK.


Combined Procedures

• As in PK, EK can be combined with other intraocular surgeries.



Success Rate

• Good to excellent, depending on the indication for surgery







FIGURE 10-3. (continued) C. Five weeks after DSEK surgery, the graft is perfectly centered and clearing nicely. D. Slit-beam view 5 weeks after surgery showing that the DSEK graft has minimal edema. The slit beam highlights the interface between the host anterior cornea and the thin posterior donor DSEK graft.







FIGURE 10-3. (continued) E. Dual Scheimpflug photography using the Galilei system showing the DSEK graft to be attached to the recipient cornea on postoperative day 1. There is mild DSEK edema centrally, but moderate edema at the edge of the graft. This peripheral graft edema typically resolves over several months. F. Moderate folds in this DSEK are seen a few days after surgery. Note the small air bubble still present superiorly. While the folds improved somewhat with time, vision did not improve significantly until the DSEK was repeated.







FIGURE 10-3. (continued) G. On postoperative day 1, the host cornea and DSEK button are severely edematous because of a large fluid cleft in the interface. The edema did not resolve over the next 2 weeks. The DSEK graft was rebubbled in the office 2 weeks postoperatively and was 100% attached and essentially clear the following day! H. One day after surgery, this DSEK graft is detached and inferiorly displaced. There is also a large inferior epithelial defect. It was thought that the eye’s low pressure from previous glaucoma surgery predisposed it to poor graft adherence.







FIGURE 10-3. (continued) I. A fairly prominent reticular interface haze is seen in this eye 1 week after DSEK. It resolved slowly over many months.

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Oct 13, 2019 | Posted by in OPHTHALMOLOGY | Comments Off on Surgery and Complications
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