41 Evisceration
Summary
Evisceration is a surgical method for eye removal while preserving the sclera of the eye. This is employed in cases of acute endophthalmitis, phthisis bulbi, or other causes of blind, painful eye without a known or suspected malignancy. Advantages of this surgery over enucleation include preservation of orbital anatomic relationships and a technically faster procedure. Prior to surgery, unless the posterior segment can be visualized, imaging must be acquired. Various techniques of scleral preservation or modification have been described and can be selected based on surgeon preference and patient factors.
41.1 Description
Evisceration is a technique in which the intraocular contents of the globe are removed without removal of the entire globe itself. This entails removing the vitreous, retina, and uvea, while preserving the sclera and the extraocular muscles that insert onto the sclera. This is in contrast to enucleation in which the extraocular muscles are disinserted and the globe is removed in its entirety.
41.2 Key Principles
The goal of evisceration is to maintain the nonvisual structure and functions of the adnexa, including providing adequate volume replacement and maintaining motility for maximal cosmetic outcome.
Evisceration allows the removal of the intraocular source of pathology without complete loss of the structure and function of the globe.
41.3 Expectations
The patient’s expectation is twofold: (1) relief of pain in a non-seeing eye and (2) a cosmetically acceptable outcome. The primary advantage of evisceration over enucleation is that the anatomical relationship of the extraocular muscles to the sclera is preserved. 1 This translates to a less complex surgery with anatomic motility giving the patient a higher likelihood of achieving his or her goal of a cosmetically acceptable outcome with relief from pain. In addition, evisceration may be psychologically easier for patients to accept than enucleation.
41.4 Indications
Indications include the following:
A blind painful eye (often with neovascular glaucoma or infectious endophthalmitis).
Cosmesis for phthisis bulbi.
Trauma.
41.5 Contraindications
The only absolute contraindication to evisceration is the presence of an intraocular malignancy because of the risk of incomplete removal of tumor and the risk of tumor spread. Relative contraindications include the following:
Blind painful eye in which pathologic review is necessary.
Severe phthisis bulbi or microphthalmos in which there is insufficient sclera to cover an adequately sized implant.
Large staphyloma that could complicate complete removal of intraocular contents.
Intraocular infection (endophthalmitis, panophthalmitis) due to theoretical risk of spread of infection to the cerebrospinal fluid space through the cut end of the optic nerve.
41.6 Preoperative Preparation and Considerations
41.6.1 Implant Choice
Implant choices in evisceration essentially break down into two categories: integrated and nonintegrated implants. 2 An integrated implant allows for fibrovascular ingrowth and possible peg placement, whereas nonintegrated implants do not. Nonintegrated implants include inert materials such as acrylic or silicone. They are relatively inexpensive and not prone to infection. Because there is no fibrovascular ingrowth, motility is not directly transmitted to the implant. Furthermore, they have higher rates of migration.
There are a number of materials used for integrated implants. Hydroxyapatite implants have been successfully used for many years. It is the main inorganic calcium phosphate salt that comprises bone. The pores within the material allow for fibrovascular ingrowth conferring increased motility and decreased migration compared to nonintegrated implants. Porous polyethylene (Medpor, Stryker, Kalamazoo, MI) and aluminum oxide bioceramic implants have been developed more recently. Various studies have revealed varying degrees of success of each implant type. A recent meta-analysis by Schellini et al that examined over 3,800 patients revealed no difference in implant exposure between porous polyethylene and hydroxyapatite implants. 2 There was a lower rate of exposure with porous polyethylene compared to bioceramic implants. The choice of implant can be a difficult one and often comes down to surgeon preference, although a few special circumstances, such as pegging or active infection, may help dictate selection.
41.6.2 Pegging
A pegged implant is one in which a sleeved socket is created within the integrated implant such that a prosthesis with a peg can fit into the socket. The advantage of this technique is that motion of the implant is directly transmitted to the prosthesis, potentially improving cosmesis. However, pegged implants have higher risks of side effects such as discharge, exposure, and infection compared to nonpegged implants. Many surgeons feel hydroxyapatite is superior to other materials in terms of the ability to support a peg sleeved socket in the long term. Typically, the peg socket is drilled into the integrated implant during a second procedure about a year after implant placement, once fibrovascular integration of the implant is complete. Therefore, patients can decide if they are pleased with the amount of motility they have without the peg before committing to this procedure. Magnetic resonance imaging with contrast can help confirm fibrovascular integration. However, in evisceration specifically, anecdotal experience has found that pegging confers too much movement to the prosthesis, allowing the edges of the prosthesis to become exposed during normal eye movement, detracting from the desired cosmetic outcome.
41.6.3 Endophthalmitis
An important consideration when considering evisceration versus enucleation is the presence of endophthalmitis or panophthalmitis at the time of surgery. Conventional wisdom dictates that placing an implant into a space that was infected would increase the risk of postoperative infection and secondary implant removal. However, numerous studies have demonstrated low complication rates in patients with endophthalmitis who have successfully received a primary, nonporous implant at the time of evisceration. 3 , 4 In these circumstances, preoperative intravenous antibiotics and postoperative oral antibiotics are indicated. At times, the sclera may become so necrotic and friable due to the inflammation from infection that an evisceration may need to be converted to an enucleation. Again, nonporous implants should be used primarily in these situations.
41.6.4 Malignancy
A criticism of evisceration in comparison to enucleation is that there is a risk of eviscerating an eye with an occult intraocular malignancy. Eviscerating in such circumstances can lead to local and distant spread of disease. In retrospective analyses of evisceration samples, malignancies have been found in 1 to 10% of cases. 5 , 6 , 7 Patients ought to be made aware of this risk prior to surgery. In addition, a dilated exam, B-scan ultrasound, CT, or MRI should be performed prior to all eviscerations to identify possible neoplasms before surgery. 8 If one has any suspicion of malignancy or the eye cannot be imaged adequately, evisceration is contraindicated.
41.6.5 Perioperative and Postoperative Antibiotics
Practice patterns have varied in regard to administering antibiotics in cases of eviscerations with implant placement. The use of perioperative and postoperative antibiotics has been a matter of physician preference. However, recent studies have suggested that both perioperative IV antibiotics and postoperative oral antibiotics do not alter the rate of surgical infections. 9 Perioperative antibiotics may be recommended in those with higher risk of infection, such as cases of poorly controlled diabetes, trauma, malnutrition, obesity, smoking, immunosuppression, or prolonged anticipated hospital stay and, of course, in cases of active infection such as endophthalmitis or panophthalmitis.
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